REMEDIAL INVESTIGATION REPORTREMEDIAL INVESTIGATION REPORT UNION SCRAP IRON AND METAL COMPANY 1608...

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REMEDIAL INVESTIGATION REPORT

UNION SCRAP IRON AND METAL COMPANY

1608 WASHINGTON AVENUE NORTH

MINNEAPOLIS, MINNESOTA

DELTA NO. 1149.185

Delta Eavtatmartal Consultants, Inc1W1 H10mqr 9, Suite 114

SLPttLMN 55112(f U) O4-2427

22, 1*89

EPA Region 5 Records Ctr.

22*8*3

EXECUTIVE SUMMARY

This report presents the results of a Remedial Investigation (RI) conducted at the Union Scrap Iron andMetal Company site located at 1608 Washington Avenue North in Minneapolis, Minnesota. Thisinvestigation was performed by Delta Environmental Consultants, Inc. for the Minnesota Pollution ControlAgency (MPCA).

This RI was conducted to characterize near surface soils as a potential source of ground watercontamination, characterize potential ground water contamination, evaluate ground water as a potentialpathway of contamination and evaluate potential risks of the contamination to human health and theenvironment from this site. The investigation consisted of researching current and background informationon the site and the area and evaluating the physical characteristics of the study area, the nature and extentof contamination, contaminant fate and transport, and performing a baseline risk assessment

The Union Scrap Iron and Metal Company owned aad operated a scrap metal and battery top and casingprocessing facility in north Minneapolis from the early 1970s until 1983. Several investigations of theUnion Scrap facility during the early 1980s determined that operations at the site had caused significantlead and porychJorinated biphenyl (PCS) contamination of site soils. Because of the threat to humanhealth and the environment from this contamination, the Environmental Protection Agency (EPA)conducted two Emergency Removal Actions in 1968. These Removal Actions involved excavation of thetop one to three feet of soil from the site and replacement with clean backfill

The RI field activities at the Union Scrap site were conducted from July 31 through September 19,1989.The activities performed include: site surveying, surface water investigation, geological investigation,soil/vadose zone investigation, and ground water investigation. The geological investigation included theadvancement of 23 soil borings terminated at varying depths to provide a complete lithologic descriptionof the site and provide soil samples for chemical analyses. The soil/vadose zone investigation focused onthe old (III material and natural soils beneath the base of the new fill brought in following the EPARemoval Action in 1988. Thirty six soil samples were collected at various depths from the site. Soilsamples were analyzed for organic compounds including volatile and semi-volatile compounds and PCBs.Soils were also analyzed for inorganic metals and cyanide.

Seven monitoring wells were installed to evaluate aquifer parameters and ground water quality. Six watertable monitoring wells were completed in the snrfidal aquifer and one deep monitoring well wascompleted in a deeper aquifer. Two rounds of ground water samples were collected from all monitoringwells. These samples were analyzed for organic compounds including: volatile and semi-volatilecompounds, and PCBs. Ground water was also analyzed for inorganic metals and cyanide. A third setof ground water samples "were taken from three weUs and analyzed for PCBs.

The local geology consists of four major units: a surficial sand and gravel unit, a sflty clay and clay unit,a deeper sand and gravel unit, and a bedrock unit The surficial sand and gravel unit was found to bebetween 43 and 51 feet thick. Based on one deep boring, the clay unit appears to be about 50 feet thick.The deeper sand and gravel unit extends to bedrock, at about 192 feet The clay unit present below thesand and gravel unit was found beneath the entire site aad appears to be acting as a confining unit in thevicinity of the site separating the surficial sand aad gravel aquifer from the deeper sand and gravel aquifer.

Ground water occurs at about 30 feet below bad surface. Ground water flow in the surficial aquiferabove the clay unit is to the southeast towards the Mississippi River. Single well recovery tests werecompleted and used to calculate the local hydraulic conductivities with these results used in the calculationof ground water flow velocity. Using the change in ground water elevation across the site as the hydraulicgradient, flow velocities ranging from 0.16 feet/day to 0.48 feet/day were calculated for the surficial aquifer.A hydraulic head difference of approximately 8 feet was observed between the surficial aquifer and thedeeper aquifer.

Executive SummaryPage 2

Two volatile organic, tetrachloroethene and irichloroethene, were detected in low part per billionconcentrations in two different soQ samples. The only other organic detected in the soil was a PCB(Arochlor 1248). It was found in low part per billion concentrations at four locations.

Seven different volatile organics were detected ia shallow ground water samples. These includedtrichloroethene, 1,1-dichloroethene, 1,2-dkUoroeihaae, 1,1 • dichloroethane, 1,1,1-trichloroethane, benzene,and xylenes. Only trichloroethene and benzene were found in ground water in concentrations greater than100 parts per billion (ppb). Several organic contaminants were found in upgradient wells and areoriginating from off-site. These contaminants are trichloroethene, 1,1, -dkhloroethene, 1,2 •dichloroethane, benzene, and xylenes. Ground water contaminants apparently originating on site are 1,1,1• trichloroethane and 1,1 - dichloroethane.

No cyanide or semi-volatiles were detected in shallow ground water. Metal concentrations were foundto either be within ranges comparable to a spring water sample from the twin cities area or, if higher thanthe spring water concentrations, to be uniformly higher upgradient, beneath the site and down gradient

No organic contaminants, cyanide, or elevated levels of inorganics were detected in the deep aquifermonitoring well

The RI also evaluated potential routes of contaminant migration at the Union Scrap site. Routes ofmigration considered were leaching from soils and transport via ground water. Transport via airbornepaiticulates is not a concern at this site because the site is covered with one to three feet of clean soil

Contaminant persistence, mobility, and transport in soils and ground water were evaluated for lead, 1,1,1 -trichloroethane, 1,1 • dichloroethene, trichloroethane, tetrachloroeihcne, and PCBs. Lead was considereddue to the very high concentrations in soO prior to the EPA Emergency Removal Actions. Soil leadconcentrations were found to be within the range of concentrations found in natural soils. Lead was notdetected in ground water samples. 1,1,1 • Trichloroethane and 1,1, - dichloroethane were found in lowppb levels in only two shallow ground water Monitoring wells, one on site and the other down gradientoff site. These contaminants may have originated at this site and appear to be migrating off site.Trichloroethene was found in only one soil sample bat was present in all shallow ground water monitoringwells. The limited extent and low concentrations of trichloroethene in on-site soils are not expected tosignificantly impact ground water. The trichloroethene concentrations in ground water are significant andare originating from an unknown, upgradient source. Tetrachloroethene was found in low concentrationsin only one on-site soil sample. Because of the low levels, limited amount and extent of this contaminantin soils, it has not and b not expected to impact ground water. PCBs were found in low part per billionconcentrations in several sofl samples, but were not detected in ground water. Because of the limitedmobility of PCBs they are expected to remain attached to soil particles and not migrate to ground water.

Human health and environmental risks were evaluated in the risk assessment The indicator chemicalsused in the evaluation were 1,1 - dkhloroethaae nod 1,1,1 - trichloroethane. All other contaminants areeither present in extremely low concentrations, of limited extent or are originating from off-site sources.

According to the risk characterization, which included evaluation of human health and environmental risks,current on-site concentrations of 1,1, • dichloroethane and 1,1,1 - trichloroethane are below bothMinnesota Department of Health Recommended Allowable Limits and Federal EPA MaximumContaminant Levels (MCLs) and also below any water quality criteria for aquatic toxiciry. Therefore,there is negligible potential for increasing public health on environmental risks from this site.

Executive SummaiyPage 3

The investigation of soil and ground water at the Union Scrap site was thorough. Minor data limitationswere found regarding detection limits for semi-volatile organics, information on the Oil material broughton site following the removal actions and sou* chemistry data between the deep soil samples and the watertable. These data limitations do not alter the conclusions of this RI report

Future work is recommended to investigate and identify the sources) of the ground water contaminationfound to be originating upgradient of the site.

Remedial action objectives and alternatives developed in the Project Support Document for soil andground water were reviewed. Alternatives to addrev soil contamination were evaluated to limit humanexposure to contaminants in soil and to limit leaching of contaminants from sofl to ground water.Alternatives for ground water were reviewed so remediation levels with a risk range of 10* and 10*7 formaximum lifetime risk would be defined. Based OB the evaluation of the RI results for both soils andground water, the recommended alternative for both media is no action.

Since no further work related to the former activities at the Union Scrap site is recommended, a feasibilityreport is not applicable.

Charter Lf Introduction

1.1 Purpose ............................................................ 11.2 Organization of the RI .................................................. 113 Site Background ...................................................... 2

13.1 Physical and Environmental Setting .................................. 2U.l.l Area of Investigation ...................................... 213.1.2 Site Description ......................................... 313.13 Topography and Surface Drainage ............................ 3

132 Site History and Operations ........................................ 413.2.1 Summary of Previous Land Uses ............. . ................ 41322 Description of Union Scrap boa and Metal Company Operations ....... 51323 Current Operations ....................................... 6

133 Previous Site Investigations ........................................ 613.4 History of Response Actions ....................................... 8

liaptcr 2.0 Stadr Area Inv

2.1 Remedial Investigation (RI) Field Activities ................................... 12.1.1 Site Surface Topographic and Area Mapping ............................ 1

2.1.1.1 Site Surface Topographic Mapping ............................ 111.12 Local Area Mapping ...................................... 2

112 Surface Water Investigation ........................................ 2113 Geological Investigation .......................................... 3

113.1 Existing Ground Water Wefl Review ........................... 3113.2 Soil Borings ............................................ 3

113.11 General Drilling, Sampling, and ClassificationMethodologies .................................... 3

1132.2 Deep Sofl Borings ................................. 4113.13 Water Table Well Borings ........................... 71132.4 Shallow Sofl Borings ............................... 7

11.4 Soil and Vadose Zone Investigation .................................. 811.4.1 Shallow Chemical Samples .................................. 1011.42 Intermediate Chemical Samples .............................. 1011.43 Deep Chemical Samples ............... . ................... 11

11.5 Ground Water Investigations ....................................... 1111.5.1 Water Table Monitoring Welb ............................... 1111.52 Deep Aquifer Monitoring Well ............................... 1211.53 Well Development ....................................... 1211.5.4 Ground Water Sampling ................................... 1311.5.5 Well Survey and Water Level Measurements ..................... 1411.5.6 Hydrogeologic Field Tests .................................. 14

Chapter 3.0

3.1 Surface Features ...................................................... 13.1.1 Topography ................................................... 13.12 Area Reconnaissance Survey .................................... 1

3.2 Surface Water Hydrology ................................................ 233 Geology ............................................................ 3

33.1 Regional Geology ............................................... 3

322 Site Geology 433.2.1 Surficial Sand Unite 43322 day Unit 53323 Deep Sand and Gravel Unit 63.3.2.4 Bedrock 7

3.4 Hydrogeology 73.4.1 Regional Hydrogeology 73.43 Site Hydrogeology 8

3.4.2.1 Surficial Sand and Grave] Aquifer : 93.422 day Layer 113.4.23 Deep Sand and Gravel and Prairie du Chien - Jordan Aquifers 12

3.5 Demography and Land Use 1333.1 Land Use 13332 Demography 14

Chapter 4.0 Nature and Brttot of Contamination

4.1 Introduction 14.2 Characterization of Contamination in Soil 2

4.2.1 Volatile Contamination 24.2.2 Semrvolatile Contamination 2423 Potychlorinated Biphenyl Contamination 242.4 Inorganic Contamination 3

4.14.1 Cyanide 34.2.4.2 Lead 342.4.3 Remaining TAL Metab 34.14.4 Summary of Inorganic Leach Testing 4

4.15 Summary of Soils Contamination 443 Characterization of Contamination in Ground Water 8

43.1 Volatile Contamination 8432 Semivolatile Contamination 9433 Polychlorinated Biphenyl Contamination 943.4 Inorganic Contamination 10

43.4.1 Cyanide 1043.42 Common Ground Water CoBCtftoents 1143.43 Trace Anarytes 11

433 Summary of Ground Water Contamination 124.4 Conclusions 14

4.4.1 Volatfle Organic* 144.42 PorychJorinated Bypaenyb 154.43 Inorganic Anarytes 15

Chanter S.O

5.1 Potential Routes of Migration 152 Physical/Chemical Properties 1

52.1 Lead 3522 1,1,1- Trichloroethane 4523 1,1- Dichloroethane 452.4 Trichloroethene 4523 Tetrachloroethene 452.6 Polychlorinated Biphenyls (PCBs) 5

53 Contaminant Persistence and Mobility 5

53.1 Acton Affecting Environmental Persistence and Mobility 5532 Lead 6533 1,1,1- Trichloroethane 653.4 1,1- Dichloroethane 753.5 Trichloroethene 853.6 Tetrachloroethene 953.7 PCBs 10

5.4 Contaminant Migration, Transport, and Fate 115.4.1 Site Conditions 115.4.2 Lead 125.43 1,1,1- Trichloroethane '. 125.4.4 1,1- Dichloroethane 135.4.5 Trichloroethene 145.4.6 Tetrachloroethene 145.4.7 PCBs 15

6.1 Public Health Evaluation . . : ............................................. 16.1.1 Indicator Chemicals ............................................. 16.1.2 Exposure Assessment ............................................ 3

6.12.1 Human Receptor Populations .......................... .' ..... 36.122 Exposure Point Concentration Estimate (fate) .................... 5

6.13 Toricity Assessment ............................................. 96.13.1 Tooticity of 1,1-Dkhloroethane ............................... 96.132 Tenacity of l.U-TrichJoroethane .............................. 10

6.1.4 Risk Characterization ............................................ 106.2 Environmental Assessment ............................................... 1363 Risk Assessment Summary ............................................... 15

* Concln*tons

7.1 Summary ........................................................... 17.1.1 Nature and Extent of Contamination ................................. 17.1.2 Fate and Transport of Contamination ................................. 17.1.2 Risk Assessment ................................................ 2

12 Conclusions .......................................................... 47.2.1 Data Limitations and Recommendations for Future Work ................... 4

Remedial Action Objectives ............................. 5

Chapter l.Q

Table 1-1

Chapter 2.0

Table 2-1Table 2-2Table 2-3Table 2-4

Chapter 3.0

Table 3-1Table 3-2Table 3-3Table 3-4Table 3-5

Table 3-6

Chapter 4.0

Table 4-1Table 4-2Table 4-3Table 4-4Table 4-5Table 4-6Table 4-7Table 4-8

Table 4-9

Historical Summary of Area Businesses

Summary of Local Well Lop Vidaily of Union Scrap SiteTarget Compound List (TCL)Target Anafyte List for Inorganics (TAL)Short List Target Compounds for Sofl Samples

Mississippi River Stage Elevation ReadingsMonitoring Well Elevation SummaryGround Water Elevation MeasurementsSummary of Hydraulic Conductivity EstimatesSummary of Moisture Content, Vertical Permeabilities,and Density of the Surficial Sand UnitSummary of Moisture Content, Vertical Permeability, andDensity of the day Layer

Chemical Sofl Sample SummarySoil Sample AnalysesVolatile Organic Contamination in SoflPCB Contamination in SoilsSummary of Inorganic Results in SoOsTrace Metal Concentrations in Natural SoilsVolatile Organic Contamination in Ground WaterContaminant ConcentratioM at Upfradient andDowngradieat WellsSummary of Inorganic Results ni Ground Water

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Chapter 5.0

Table'5-1

Chapter 6.0

Table 6-1Table 6-2

Physical and Chemical Data for Organic Contaminants

ARARs for Site ContaminantsConcentration of Pollutants 10 AquaticOrganisms at Equilibrium

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FIGURES

Chapter 1.0

Figure 1-1Figure 1-2Figure 1-3Figure 1-4Figure 1-5Figure 1-6

Chapter 2.0

Figure 2-1Figure 2-2Figure 2-3Figure 2-4Figure 2-5Figure 2-6Figure 2-7Figure 2-8Figure 2-9Figure 2-10Figure 2-11Figure 2-12Figure 2-13

Chapter 3.0

Figure 3-1Figure 3-2

Figure 3-3Figure 3-4Figure 3-5Figure 3-6Figure 3-7Figure 3-8Figure 3-9Figure.3-10Figure 3-11Figure 3-12Figure 3-13Figure 3-14

Chapter 4.0

Figure 4-1Figure 4-2Figure 4-3Figure 4-4

Site Location MapArea Topographic MapVicinity MapSite MapMaterials Processing SchematicPrevious Sofl Boring Locations

Site Topographic MapLocal Area MapGeologic Cross SectionCross Section A-A'Cross Section B-B'Deep Soil Boring LocationsWater Table WellShallow Soil Boring LocationsGeneralized Shallow Soil Boring SchematicShallow Chemical Sofl Sample LocationsIntermediate Chemical Sofl Sample LocationsDeep Chemical Sofl Sample LMonitoring Well Location Map

Sorficial Geology MapGeneralized Geologic Cross Section of MetropolitanArea (from Horn, 1983)Bedrock Geology MapSoil Boring and Monitorial Well Location MapCross Section C-C and D-D'Cross Section (XTCross Section D-D'day Unit Surfece Elevation Contour MapGeologic Cross Section Location MapCRMS Section A-A'Cross Section B-B*Monitoring Well Location MapWater Table Contour MapPrairie da Odea-Jordan Aquifer Map

Lead Concentration ProfilesVolatile Contamination in Grand WaterPolychlorinated Biphenyl Concentration in Ground WaterTrichloroethene Concentration ContourContour Map (August 7,1989)

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Chapter 7.0

Figure 7-1 Sofl ContaminationFigure 7-2 Volatile Contamination in Ground Water

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APPENDICES

Appendix A Union Scrap Preliminary Evaluation Report Prepared by International Technology Corporation1988

Appendix B Site Assessment Report for Union Scrap Prepared by Roy F. Weston, Inc. 1985Appendix C Report of Soil Borings and Analyses at Union Scrap Prepared by Sofl Exploration Company

and Twin City Testing. Inc. 1980Appendix D Soil Borings and Analysis at Union Scrap Prepared by Braun Environmental Laboratories, 1986Appendix E Summary Report of October 1987 EPA TAT (Weston • Sper) InvestigationAppendix F CERCLA Removal ActionsAppendix G MPCA Sample ResultsAppendix H Minnesota Geological Survey Water Well Logs Identified Within a One Mile Radius of the

Union Scrap SiteAppendix I Union Scrap RI Soil Boring LopAppendix J Monitoring Well Construction Forms, Minnesota Department of Health Well Records, and

Precision Environmental Well Development ReportAppendix K Surficial Sand and Gravel Sample Particle Size Distribution CurvesAppendix L Clay Layer Particle Size Distribution CurveAppendix M Slug Test Analyses, Regression Curves, and Raw Field DataAppendix N Soil and Ground Water Sampling Information SheetsAppendix O Analytical Results

REMEDIAL flfVESTIGATION REPORT

UNION SCRAP IRON AND METAL COMPANY

1608 WASHINGTON AVENUE NORTH


DELTA NO. 1149.185

L6 INTRODUCTION

LI PurposeThe purpose of this Remedial Investigation (RI) Report is to present the results of Delta Environmental

Consultants, Inc. (Delta's) investigation of soils aad ground water at the Union Scrap Iron and MetalCompany site located at 1608 Washington Avenue North in Minneapolis, Minnesota (Figures 1-1 and 1-

2). The objectives of the RI were to:

• Characterize near surface soils at a potential source of contamination to ground water.

• Characterize potential ground water contamination and evaluate ground water as a potentialpathway of contamination; and,

• Evaluate potential risks of the contamination to human health and the environment.

1.2 Organization of the RI

The results are presented in seven chapters. These are outlined below with a brief description of content.

Chapter 1 Introduction - This chapter provides background information on the site and the problem.

Chapter 2 Study Area Investigation - This chapter describes all RI field activities.

Chapter 3 Physical Characteristics of the Study Area • Results of the soils and ground waterinvestigation are presented along with interpretation of the physical setting.

Chapter 4 Nature and Extent of Contamination - This chapter presents the chemical characterizationresults for the site; focusing primarily on soil and ground water.

•

Chapter 5 Contaminant Fate and Transport • Chapter 5 utilizes information from Chapters 3 and4 to evaluate contaminant persistence, potential routes of migration and actualcontaminant migration.

Chapter 6 Baseline Risk Assessment - In this chapter, exposure to contaminants is evaluated,contaminant tenacity twnH, and risks posed by contamination from the sitecharacterized.

Chapter 7 Summary and Conclusions • This chapter provides a summary of Chapters 3, 4, S, and 6and presents conclusions and recommendations concerning site characterization, futurework, and remedial action objectives. It also provides a preliminary identification ofapplicable or relevant aad appropriate requirements (ARAR's) by specific media.

CANADA

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MINNEAPOLIS •• STXPAUL

ROCHESTER ,

^ "AUSTIN

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FIGURE 1-1SITE LOCATION MAP

UNION SCRAPMINNEAPOLIS, MINNESOTA

PftOJCCT NO.

10-89-185QME

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MINNEAPOLIS NORTH. MINN.MINNEAPOLIS SOUTH, MINN.

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PHOTOREVISED 1972 AND 1980DMA 7374 III SE-SERIES V|72

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PROJECT NO.

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Remedial Invettintton ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis MinnesotaDelta No. 11-89-185Page 2

L3 Site Background

This chapter introduces the Union Scrap Iron and Metal Company site located at 1608 Washington

Avenue North, Minneapolis, Minnesota (Figure 1-1). The purpose of this chapter is to provide, from

easting data, background information on the site aad • description of relevant area and site, surface, and

subsurface features. This information summarizes previous site activities, problem(s) associated with and

resulting from these activities, and provides an overview of the physical and environmental setting.

U.I Physical and Environmental Setting

L3.1.1 Area of Investigation

The Union Scrap site is located in the SWl/4 , Section IS, T29N, R24W. The site's latitude and

longitude are 44° 59.73'N, 93° l&CTW, respectively. The site is approximately 1,200 feet west of the

Mississippi River and one mile north/northwest of downtown Minneapolis, Minnesota (Figure 1-2).

The area surrounding the site is a general manufacturing area. The major businesses in the area are

involved in scrap metal processing. Other businesses scattered throughout the area consist of taverns,

cafes, and service stations.

This area of the city is generally depressed. Heavy equipment, cranes, loaders, etc. are used throughout

the area. Oily patches of soil, and oOy residua are common on the streets and in many of the scrap yard

areas.

The areas north and sooth of the site are relatively Oat, with most businesses residing on either

Washington Avenue or Second Street This business district extends over a mile in both directions.

*

East of Second Street there b a gradual decline in elevation toward the Mississippi River. Approximately

100 feet to the west of the site is Interstate 94 (1-94). Further to the west beyond 1-94 are residential

areas of North Minneapolis.

Aerial photos predating 1-94 construction ia the tote 1970's show the area along the west side of

Washington Avenue from several blocks sooth to several blocks north of the site to be businesses similar

to those now existing on Washington Avenue and Second Street, Le. scrap yards and auto salvage yards.

Remedial Investigation ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page}

An October 1953 aerial photo from the photographic analysis performed by Lockheed (Lockheed, 1985)

shows auto salvage and scrap yards on both sides of Washington Avenue. Review of Minnesota Historical

Society records shows many of these businesses have existed in the area at least since the early 1930's.

13.1.2 Site Description

The Union Scrap site is located on the northeast comer of the intersection of Washington Avenue North

and 16th Avenue North (Figures 1-2 and 1-3). The site extends approximately 155 feet east to west and

125 feet north to south.

The site is bounded on the south by 16th Avenue beyond which is currently an empty k>L The aerial

photo sequence (Lockheed, 1985) shows the empty lot to have been an auto salvage area in '1953, 1964,

and 1969. In the 1979 photo, this area appears to be a scrap or waste processing area. Immediately east

of the site are two sets of Soo Line railroad tracks that serve the scrap yards and tie into Burlington

Northern Railroad (BNRR) lines northeast of the site. East of the tracks in the same block are two scrap

metal salvage yards. North of the site is an E-Z Stop convenience store and gas station. Several

underground storage tanks are located on the station property which are used for storage of kerosene,

diesel, leaded, and unleaded gasolines, and racing fuel In addition, fuel offloading piping and pumps are

still in place along the Soo Line Railroad tracks on the east side of the station. Immediately west of the

site is Washington Avenue. Continuing west, the land surface drops off sharply to an 1-94 access road;

then further west, 1-94. The elevation of the access road, which was apparently excavated during 1-94

construction, appears to be 25 to 35 feet below the site elevation. The site vicinity is shown in Figure

1-3.

m

The site is currently vacant aad level except for some concrete debris and minor subsidence in thenorthwest corner (Figure 1*4). Activities while the site was active are discussed in Section 1.3.2 SiteHistory and Operations. Additionally, a description and chronology of response actions at the site ispresented in Section 13.4, History of Response Actions.

L3.1J Topography and Surface DralnateThis area of Minneapolis, which borders the Mississippi River, is underlain by terraced alluvial deposits

(Meyer, 1985). This type of terrace deposit is typically flat with little vertical relief, as evidenced by the

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CONVENIENCESTORE '

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UNION SCRAP SITE1608 WASHINGTON AVENUE

17TH AVENUE

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UNION SCRAP SITEMINNEAPOLIS, MINNESOTA

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10-89-185oat

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UNION SCRAPMINNEAPOLIS. MINNESOTA

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10-89-185OMC.

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CnvlronnMntolConsultant!, Inc.

Remedial Investiiation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149-185Page 4

natural terrain surrounding the site (Figure 1-2). The primary vertical relief in the area is the 1-94 road

cut to the west of the site and the slope adjacent to the Mississippi River to the east Surface drainage

and runoff are directed to the combined sanitary and storm sewers on Washington Avenue. This

combined sewer system is routed to the Pip Eye Sewage Treatment Facility located south of St Paul.

Line flow is bypassed to the Mississippi River during extreme precipitation events when the excess stormflow volume exceeds the capacity of the sewer lines and the treatment capabilities of the facility. Figure

1-3 from the Preliminary Evaluation Report by IT Corporation 1988 (Appendix A) presents the locations

of the storm and sanitary sewers which serve the area.

L3.2 Site History and Operation*

1.3.2.1 Summary of Previous Land Uses

Records of the Minnesota Historical Society (specifically the Polk Directories for the city of Minneapolis

subsequent to 1930) have been screened for previous uses of the Union Scrap site and nearby properties.

Table 1-1 presents a summary of businesses by address and date(s) of occupancy.

The area has seen a mixture of residential, commercial, and industrial properties. However, the most

enduring and largest area businesses were automobile salvage yards, scrap metal yards and petroleum

product storage and retail sales facilities.

The 1600 block of Washington Avenue has been the site of auto salvage operations from the 1930s until

the 1970s (Table 1-1). These salvage yards lined both sides of Washington Avenue north and south of

the site for many years. The property north of the site, at the location of the current E-Z Stop gas

station, has been the location of retafl gasoline sales since the 1930s. The Old Colony gas station

operated there for about 40 years. There is also a 1930 reference to BB Fuel Company located directly

west across Washington Avenue.

Northwest of the site across Washington Avenue, probably on the corner of Washington and 17th Avenue,

two manufacturing facilities operated for many yean. From some time in the 1940s until the 1960s,

Great Western Laboratories operated a soap manufacturing plant During the later 1960s and 1970s,

Advance Rubber Company operated in the same location.

TABLE 1.1

Historical Summary of Area Businesses9

1600 and 1500 Blocks of Washington Avenue NorthMinneapolis, Minnesota

Delta No. 1149-185

Yearfsl Address Business

1930 1514 Residence1529 Sussman's Auto Parts1601 B-B Fuel Company1616 Minneapolis Auto Parts Company (ret)1629 Cleaners Equipment Supply Company

1937 1500 Vacant1514 Residence1529 Sussman's Truck and Auto Parts1601 B-B Fuel Company1608 Midwest Auto Wrecking1616 Minneapolis Auto Parts1629 Vacant

1946 1500 Vacant1514 Residence1529 Sossman's Auto Parts1601 B-B Fuel Company1608 Residence1616 Minneapolis Auto Parts1622 Old Colony Gas & Oil1629 Great Western Laboratories (soap mfrs)

1952 1500 Nate's Auto Parts (ret)1514 Residence1529 SatMian Auto Parts (wreckers)1601 Vacant1608 Arrow Auto Parts1616 Minneapolis Auto Parts Company (ret)1622 ' Old Colony Gas & Oil (station)1629 Great Western Laboratories (soap mfrs)

1957 ' 1500 Nate's Auto Parts (ret)1514 Residence1529 Sussman Auto Parts (wreckers)1600-08 Speed Gems, a Division of Arrow Auto Parts Co.1601-23 Minneapolis Auto Parts Company (yds)1616 Minneapolis Auto Parts Company (ret)1624 Old Colony Gas A Oil Company (station)1629 Great Western Laboratories (soap mfrs)

Table 1-1 ContinuedPage 2

1962 1500 Kate's Auto Parts (ret)1514 Rctidence1529 Sussman Auto Parts (wreckers)1601-23 Minneapolis Auto Parts (yds)1608 Metal Tool & Equipment Company (mill sups whol)

Alliance Steel Service Company (junk dealers)WQlman & Son Trucking Company

1616 Minoapolis Auto Parts Company (ret)1624 Old Colony Gas A Oil Company (station)1629 Great Western Laboratories (soap mfirs)

1966-67 1500 Nate's Auto Parts (ret)1514 Vacant1529 Lisbon Truck Sales (used)1600 Auto Parts Inc. (used)1601 Minneapolis Auto Parts Company (yd)1608 Vacant1616 Minneapolis Auto Parts Company (ret)1624 OU Colony Gas & Oil Company (station)1629 Advance Rubber Company (mfrs)

1972 1500 Vacant1514 Vacant1529 Lisbon Truck Sales (used)1600 United Auto Parts, Inc. (stge)1601 United Auto Parts, Inc. (yd)1616 Mapco Minneapolis Auto Parts, Inc. (ret)1617 Mapco Minneapolis Auto Parts, Inc (yd)1624 Old Colony Gas & Oil Company (station)1629 Advance Rubber Company (mfrs)

1976 1529 Lisbon Truck Sales (used)1600 Union Scrap Iron and Metal Company (stge)1601 United Auto Parts, Ins. (yd)1616 Mapco Minneapolis Auto Parts, Inc (ret)1617 Mapco Minneapolis Auto Parts, Inc (yd)1624 Old Colony Gas & Ofl Company1629 Advance Rubber Company (mfrs)

*

1977 1500 Union Scrap Iron and Metal Company (stge)1514 Union Scrap Iron and Metal Company (stge)1529 Lisbon Truck Sales (used)1600 Union Scrap Iron and Metal Company (stge)1617 Mapco Minneapolis Auto Parts, Inc (yd)1624 Vacant1629 Advance Rubber Company (mfrs)


1981-82 1500 Union Scrap Iron and Metal Company (stge)1514 Union Scrap Iron and Metal Company (stge)1600 Union Scrap Iron and Metal Company (stge)1616 Vacant1617 Mapco Minneapolis Auto Parts, Inc. (yd)1624 OU Colony Gas & OH Company (station)

1987 1500 Union Scrap Iron and Metal Company (stge)1514 Union Scrap Iron and Metal Company (stge)1600 Union Scrap Iron and Metal Company (stge)1616 Vacant1624 E-Z Stop - Crown Oil (station)

1989 1500 Union Scrap Iron and Metal Company (stge)1514 Union Scrap Iron and Metal Company (stge)1600 Union Scrap Iron and Metal Company (stge)1624 E-Z Stop - Crown Ofl (station)

• Information obtained from Polk Directories; City of Minneapolis, for yean listed above. The PolkDirectories are located either in the Minnesota Historical Society or the Minneapolis City Library.

Even numbered addresses are on the east side of Washington Avenue North; odd numbered addresses areon the west side.

klw.706

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMioneapolif, MinaetotaDelta No. 11-89-185

5

Land use east and south of the site has been primarily scrap metal processing yards.

The first references to Union Scrap Iron and Metal Company at this location date back to the mid-1970s.

As can be seen in Table 1-1, this company also used portions of the 1500 block on Washington Avenue

for storage.

Description of Union Scran Iron and Metal Company Operations

The Union Scrap Iron and Metal Company owned and operated a scrap metal and battery top and casingprocessing facility at 1608 Washington Avenue North, Minneapolis, Minnesota. The company has

occupied the property since the early 1970's and operated the facility on and off from the early 1970's

(approximately 1972) until 1983 (MPCA file information). The company filed for bankruptcy in 1985.

The principal operation at the site was processing of used battery tops and casings. These were hauled

by truck from the "Shaffer* site several blocks to the sooth. The "Shafer* site is owned by the Minnesota

Department of Transportation and was leased to the Union Scrap Iron and Metal Company. These

operations are described in Section 1.3, Operations and History, of the evaluation report of the

preliminary RI/FS Work Plan prepared by International Technology (IT) Corporation in March 1988(Appendix A). Additional information is provided in the site assessment report Section 2.0, Site Location

and History, for the Union Scrap Iron and Metal Company prepared by Roy F. Weston, Inc. (Weston)

for the Environmental Protection Agency in May 1965 (Appendix B).

Briefly, the battery parts were crushed in a hammer mill and sorted on a shaker table. Resulting

recyclables were lead oxide, battery posts, and the casing 'pulp*. The rubber wastes were generally.*

landfilled. As recycling economics proved unfavorable and area landfills no longer accepted these wastes,

they were stockpiled on site. The Minnesota Pollution Control Agency (MPCA), Weston. and IT

Corporation all found large piles of these and other wastes on site. Figure 1-5 presents a materials

processing schematic for the site. A materials balance for the operation b not available.

In addition to the battery operations, other materials were collected on site. MPCA and city of

Minneapolis file references indicate large quantifier* of electric motors were occasionally stockpiled. Also

electrical equipment such as transformers were found 00 site. The final item of significance b that drums

BATTERY TOPS ANDPOLY CASES FROMTHE SHAFER PLANT

HAMMER MILLSHAKER TABLE

LEADOXIDE

BATTERYPOSTS RUBBER

POLYPULP

BACK TOSHAFER TOBE MIXED

WITH PLATESAND SENT TOTARA CORP.

TOTARA CORP

TOLANDFILL

TOPLASTIC

RECYCLER

OPERATIONAL LIQUID DISCHARGE TO SANITARY SEWER

VSITE RUN-OFF DISCHARGE TO STORM SEWER

VFIGURE 1-5

MATERIALS PROCESSING SCHEMATICUNION SCRAP SITE

1608 WASHINGTON AVENUE N.MINNEAPOLIS, MINNESOTA

PROJECT na11-89-185wit8-29-89

PMPAMD ftBDO/LS

OoltaEnviron mentalConsultant*. ln«.

Remedial Investigation ReportUnion Scrip Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 6

of material have been observed on site. These were observed to contain lead battery posts, but othersmay have held various fluids.

L3.2J Current Operations

There are no activities currently taking place at this site. In 1988, MPCA and EPA arranged for removal

and proper recycling and disposal of on-site soOs and wastes. Additionally, the city of Minneapolisdemolished and removed the building. Following the removal actions, the site was backfilled and leveledwith clean fill material The removal actions are dboitv^ in greater detail in Section 13.4, History of

Response Actions.

1.3J Previous Site Investigations

Several short term, limited scope investigations have taken place at the Union Scrap site over the past

ten yean. This section supplements the reports by Weston, 1985 (Appendix B) and IT Corporation, 1988

(Appendix A) and provides a summary of previous investigative activities and results with a focus on on-

site, subsurface investigations.

The earliest investigations concerning this site are recorded in MPCA file memos and correspondence

between and among the MPCA, the city of Minneapolis, and the Union Scrap Iron and Metal Company.

One early reference to the kinds of materials and wastes associated with the site is a ktter from theMetropolitan Waste Control Commission to Union Scrap Iron and Metal Company dated April 1980.

This letter makes reference to discharges from the site to a 30-inch sanitary sewer line draining south

along Washington Avenue. The line was inspected and found to contain Tead material as much as one

foot. deep*. Preliminary results showed a total solids level of 714 percent with the lead concentration

being 55.4 percent expressed as lead (Pb) Le. approximately 550,000 parts per million (ppm).

From 1979 through 1988, there were several limited scope investigations related to this site. Results are

briefly discussed in Section 1.4 • Problem Assessment of the IT Corporation report (Appendix A). A

summary of investigations and findings are presented in Table 1-1 of the same report

Abo shown in Table 1-1 of the IT report, is that most sampling between 1980 and 1986 was related to

piles of on-site wastes, surface soils, surface water run-off and ambient air. These wastes, including

Remedial Investigation ReportUnion Scrap Iran and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page?

surface soils, were removed during the two EPA Emergency Removal Actions in 1988. The importance

of including this information lies in presenting the magnitude and duration of serious contamination

problems on this site. Nearly all materials • waste or otherwise • which at various times covered most of

the site were contaminated wastes subject to leaching during precipitation and melting events.

Very little subsurface information was available prior to this RL There were only two instances of soil

borings, along with subsurface sampling and analyse*. These were performed by Sofl Exploration

Company in 1980 and Braun Environmental Laboratories in 1986. The remainder of this section identifies

specific site activities from these investigations which provide background for the current RI/FS activities.

Copies of original documents are presented in Appendix C, Report of Soil Borings and Analyses at Union

Scrap Iron and Metal Company prepared by Sofl Explorating Company and Twin City Testing, Inc., 1980,

and Appendix D, Soil Borings and Analyses at Union Scrap Iron and Metal Company prepared by BraunEnvironmental Laboratories, 1986.

In August 1980, Union Scrap Iron and Metal Company hired Soil Exploration Company along with Twin

City Testing and Engineering Laboratory, Inc. to advance two soil borings and take continuous soil

samples at two on-site locations. These locations are shown on Figure 1-6. Boring logs and chemistry

results are presented in Appendix C On-site soils were found to consist of fill materials underlain by

sandy alluvium. Boring SB-D showed a lowered pH of 43 standard units (s.u.) from five to nine feet

below the land surface (BLS). The remainder of the soil column generally had pH values ranging from

6 to 8 s.u.

The depths at which lowered pH values were found correspond closely with a zone of elevated sulfate

levels ranging from 1,400 to 5,000 ppm from seven to thirteen feet BLS. Boring SB-E did not show

elevated, teachable metal or sulfate contamination or lowered pR

In 1986, Braun Environmental Laboratories condocted a limited investigation at the Union Scrap site for

the Minneapolis Community Development Agency (MCDA). The investigation consisted of two test

borings with subsequent analysis for porycUorinated biphenyls (PCS), volatile organic compounds (VOCs)

and teachable metals including Arsenic (As), Barium (Ba), Cadmium (Cd), Chromium (Cr), Lead (Pb),

Mercury (Hg). Selenium (Se), and Silver (Ag>

CONVENIENCESTORE

ASPHALT

CONCRETE RUBBLE IN ASURFACE DEPRESSION

CU

FORMERBUILDING

FORMER^CONCRETE

PADAREA '

/ST-6

sT-7

I ___ /

16TH AVENUE

PREVIOUS SOIL BORING BYSOL EXPLORATION CO.. 1980

PREVIOUS SOIL BORING BYBRAUN ENVIRONMENTALLABORATORIES. 1986

VACANTLOT

~1

0

I40

SCALE: 1 IN. - 40 FT.

BUUXNO

FIGURE 1-6PREVIOUS SOIL BORING

LOCATIONSUNION SCRAP

MINNEAPOLIS. MINNESOTA

PMJtCT NO.

10-89-185MIC

8/29/89EnvfrwHTMntolConsultants. Inc.

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis MinneaotaDelta No. 1149-185PageS

Boring locations are shown on Figure 1-6 and the logs and chemistry results are presented in Appendix

D. Both borings show GU materials to five or six feet underlain by alluvial sands to the end of theborings, approximately 30 feet BLS.

Depth of sampling for Volatile organic compounds (VOCs) is not indicated; however, no detectableamounts of VOCs were detected in either boring.

Leachable metals (E.P. Toxicity Method) were analyzed in samples from a depth of 15 and 7.5 feet in

both borings. No significant teachable metals were found except lead. Leachable lead concentrations atthe 15 foot depth ranged from &5 milligrams per liter (mg/1) in ST-7 to 40 mg/1 in ST-6. Both of these

samples would be considered hazardous waste according to the Resource Conservation and Recovery Act

(RCRA) standard of 5.0 mg/1 in State and Federal regulations. At the 7.5 foot depth, ST-6 showed

teachable lead of 0.59 mg/1 and ST-7 at 5.4 mg/L The sample from ST-7 would be considered hazardouswaste.

Soils were analyzed for PCB's at the same depths as metals. PCBs were found in all samples. ST-6

showed a consistent profile with about 12 milligrams per kilogram (mg/kg) at both depths. ST-7 had 130

mg/kg at 15 feet and 5.0 mg/kg at 7.5 feet The shallow sample in ST-7 exceeds the federal and state

criteria of 50 mg/kg for PCBs in the Toxic Substances Control Act (TSCA) and the Minnesota HazardousWaste rules (Chapter 7045).

In summary, these investigations indicate that lead aad PCB contamination were present and widespread

in surficial soils. Elevated levels of sulfate and depressed soil pH were also in evidence. Leaching of

contaminants to underlying soils was also occurring at the site. This is seen in boring ST-7 with teachable

lead above the standard of 5.0 mg/1 for hazardous waste at a depth of 7.5 feet

1.3.4 History of Response Actions

This section presents a chronological listing of Response Actions at the Union Scrap site located at 1608

Washington Avenue. Each listing b supplemented with a short description of activities.

Remedial Investigation ReportUnion Scrap Iron and Meul Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 6

determine depth to bedrock and deep glacial stratigraphy and, to install a deep aquifer monitoring well,

respectively. The remaining soil borings were not advanced to sufficient depth to identify the clay unit

The clay layer surface elevations for the three day definition borings were contoured and are presented

on Figure 3-8. Based on the three observation points, the clay surface has a slope of five percent towards

the east-northeast

The thickness of the clay unit was defined at only one location, bedrock boring B-14B. The top of the

clay unit was observed at 43 feet below the ground surface and continued to a depth of 84 feet below

the ground surface. Samples of the unit were collected and described at five foot intervals from B-14A

from 43 to 57 feet where this boring was terminated. Samples were collected at 10 foot intervals from

60 to 86 feet from B-14B. The upper 10 to 15 feet of the unit consists of interlayered gray sflt with very

fine sand grading to a gray lean clay. A dease gray, clay till was observed from 57 feet to approximately

65 feet From 65 to 84 feet, the unit consists of a moderately dense, brown clay till with sand.

One lined spoon sample was collected from the bate of B-14A from 55 feet to 57 feet below the ground

surface. A grain size distribution curve was developed for this sample based on the sieve analyses and

hydrometer tests. This curve is presented in Appendix L The particle size distribution analysis showed

that 56.4 percent of the sample was clay, 32.7 percent silt, 10.1 percent sand, and 0.7 percent as gravel

This distribution is characteristic of a glacial tin with the primary particle size being clay, but also

including percentages of coarser material Therefore, for purposes of this report, this unit will be referred

to as clay.

3.3.1.? Deep Sand and Gravel Unit

The deeper sand and gravel unit was investigated by completing boring B-14B, to the first bedrock unit

The deep sand and gravel unit began at a depth of approximately 84 feet below the surface, although the

boundary between the base of the clay unit and this unit was somewhat gradational The split spoon

sample from 79 feet to 81 feet showed a dense brown clay. The sample from 84 to 86 feet showed a

coarse sand with gravel and clay but was lets dease. The sample at 89 feet to 91 feet was a medium to

coarse sand with only a trace of clay. The distinction of 84 feet as the base of this unit was determined

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 9

August1980

May1985

November1985

October1986

December1986/January1987

October1987

December1987

April1988

Union Scrap Iron and Metal Company hired Soil Exploration Company and Twin CityTesting and Engineering. Inc. to advance on-site soil borings and take soil samples formeasurement of pH, teachable metab and sulfates. Results indicated a shallow soil zoneof elevated sulfate levels and lowered pH No significant teachable metab were found(Appendix C).

EPA Technical Assistance Team (TAT) performed a Site Assessment at the Union ScrapSite. Samples were collected of on-tite water, soil and rubber chips. Results showed highlead contamination in all samples. Recommendations were to control site access, removewaste piles, sample soils, cap the area to control airbora contaminants and install groundwater monitoring wells (Appendix B>

A security fence was constructed and waste piles were stabilized with tarpaulins asreferenced in Appendix E

The Minneapolis Community Development Agency (MCDA) retained BraunEnvironmental Laboratories to advance two borings on the site and collect soil samplesfor analysis of PCBs, VOCs, and teachable (E.P. Tenacity Method) metals. Results showedno indication of VOCs; however, PCBs and significant lead contamination was found(Appendix D).

Mr. Richard Rosen, a potentially responsible party (PRP) arranged for removal of 773tons of battery casing material to Louisiana (Appendix F).

To confirm that a removal action was stfll required and what magnitude of action, EPA's,TAT took soil profile samples at six on-site locations. Results for total lead showedsignificant contamination in surface soils up to 87,600 mg/kg. Lead contamination at onefoot dropped off significantly with the highest being 285 mg/kg. The highest concentrationat 3 feet was 242 mg/kg and at 4 feet, 34 mg/kg. An off-site background surface sampleshowed 492 mg/kg with 333 mg/kg at six inches. These were taken in a field 1/4 milesoutheast of the site (Appendix E).

EPA Region V approves removal action (Appendix T).

EPA emergency removal action performed by O.R Materials Corporation removed scrapmaterials for recycling or proper disposal and upper one to three feet of contaminatedsoils for disposal. An underground storage tank was discovered and removed from the

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMurneapoiif, MinnesotaDelta No. 11-89-185Page 10

September1988

September1988

east central property boundary. Some debris, the cement pad, and the building remainedon site. Waste materials were visible beneath the cement pad. The removal action reportand analytical results from samples collected during the Geld activities are presented inAppendix F.

SurOcial soils were most highly contaminated - up to 66£00 mg/kg total lead in theconcrete pad area south of the building. Other site areas showed less lead contamination.Lead levels decreased with depth, generally down to background levels Le. less than 300mg/kg total lead within a couple of feet of the surface.

The site was backfilled with clean fill from a residential area in north Minneapolis. Thefill was obtained from Mill City Excavating and Landscaping.

MPCA staff sampled several site areas for teachable metals and PCBs. Results indicatedelevated total lead in several samples and teachable lead levels (EP Toxicity Method) intwo samples making the sediment hazardous waste. These results are presented inAppendix G.

The city of Minneapolis arranged for demolition and disposal of the on-site building(MPCA Project File).

November/December1988 EPA performed a second removal action at the site removing debris, the cement pad, and

additional contaminated sofls. The site was backfilled and leveled with clean fill. Theonly remaining debris on site is some concrete foundation rubble in the northwest cornerof the site. This material tested ion-hazardous for lead.

In total, 3,000 tons of hazardous materials from the site were disposed. Additionally, eightrail cars of battery casings were recycled at a processing facility in Louisiana (Appendix

2.0 STUDY AREA INVESTIGATION

2.1 Remedial Investigation ntT> Field ActMttei

Remedial Investigation field activities were carried out at the Union Scrap site from July 31 through

September 19, 1989. Field activities were designed to provide information on site geology, and

hydrogeology, and to enable the evaluation of the extent and magnitude of soil and ground watercontamination originating from the site.

Specific RI field activities included the following:

• Surface Topographic and Area Mapping

• Surface Water Investigation

• Geological Investigation

• Soil and Vadose Zone Investigation

• Ground Water Investigation

The following sections describe the activities completed during the RI field investigations.

2.1.1 Site Surface Topographic and Area Mapping

2.1.1.1 Site Surface Topographic Mapping

A detailed site topographic survey was performed by Delta. The purpose of the site topographic survey

was to provide a detailed site map with a scale of at least one inch equals 40 feet and a d5 foot contour

interval showing surface elevations, contours, and all significant site features. Additionally, the survey was

utilized to accurately identify and locate all boreholes and monitoring wells.

From the corner of 16th Avenue and Washington Avenue, the rectangular shaped property extends

approximately 125 feet north and 155 feet east (Figure 1-4). To provide a detailed map, a 20 foot by 20

foot grid was established on site by placing temporary metal stakes along the north and west sides of the

prdperty. This produced a 7 x 9 grid with 63 survey points. In addition, a grid of 10 feet by 10 feet was

used in the northwest corner of the property where the former building was located and which presently

contains a concrete rubble pile. This is the only site area with any significant relief. The city of

Minneapolis fire hydrant located on the corner of 16th Avenue and Washington Avenue was used as the

reference point for the surveying. The elevation of the hydrant is referenced to the National Geodetic

Vertical Datum (NGVD). This elevation was acquired from the city and used to calculate the elevation

at all of the surveyed locations. The survey also included 15 proposed boring locations, 12 on site and

3 off site, and 7 additional elevations of significant points. The additional points included the centerline

Reniedfat Involution ReportUoioo Scrip Iran and Meul Company1606 Washington Avenue NorthMinneapotii, KGnoetouDelta No. 11-89-185Pa|e2

of 16th Avenue, the curb edge adjacent to Washington Avenue, and the edge of the asphalt parking lot

to the north of the site (Figure 2-1). A total of 109 points were identified, surveyed and referenced to

theNGVD.

These elevation data were contoured and a plan view contour map with a O5 foot contour interval was

generated. This map is presented as Figure 2-L

Site surveying was completed prior to initiation of Held activities. Due to standing water on the site,

approximately 36 cubic yards of clean fill material was placed at four on-site locations to provide a

suitable working area to complete several soil borings and install a monitoring well Consequently, Figure

2-1 represents the site topography immediately prior to initiation of the field work. Elevation changes

due to the fill do not significantly affect site topography.

2.1.1.2 Local Area Mapplni

A reconnaissance survey to identify active businesses and industrial facilities within a two block radius

of the site was also completed. This survey was undertaken specifically to identify above and below

ground storage tanks, processing plants, cleaning facilities, scrap piles, or any other feature or activity

which may have or potentially could have affected the Union Scrap site. The local area map is presented

as Figure 2-2.

2.1.1 Surface Water Investigation

Due to the size, location,'generally level nature of the site and the backfilling associated with the EPA

Emergency Removal Action in 1988, a surface water investigation was not included as part of the scope

of-work in the RI Work Plan. However, some ponding of rain water occurs on the site at locations

primarily along the southern and eastern boundaries. On Jury 31,1989, the day RI field activities were

initiated, standing water was present at four previously marked soil boring locations. One representative

water sample was collected for chemical analysis for potychlorinated biphenyb (PCB's) and total lead.

The sample was collected from the discharge note wed to direct the flow as pumping was initiated. The

analysis was used to characterize the water far sanitary sewer discharge to the Metropolitan Waste

Control Commission (MWCC) collection line. Portable pumps were used to pump the standing water

eastward to the combined storm and sanitary sewer along 16th Avenue.

GRASSYAREA

LEGEND

i>

CO

FENCE-I—I 1- RAILROAD TRACK

O LIGHT POLE

» UTILITY POLE

GROUND SURFACE CONTOUR

LOCATION OF SURFACE WATER (PUDDLE)GRAB SAMPLE

SIGNE - Z STOP

CONVENIENCE STOREPARKING LOT

NORTH

NOTE. HAP COMPLETED PRIOR TO RI FIELD ACTIVITIES

40

SCALE M FEET

FIGURE 2-1

SITE TOPOGRAPHIC MAP


Ma

11-89-185DATE

8/28/89

PREPARED W

MVM/PRDelta

IIM.

18TH

UNIONPHOTOGRAPHIC

SPECIALISTS

(PHOTOGRAPHICPROCESSING)

B t MSERVICE

(AUTOMOMLCSTARTER ANDALTERNATOR

RCPA1R StO»>

17TH

E ZSTOP(RETAIL

GASOLINESTATION)

UNIONSCRAP

SITE

16TH

Ul

•z.u

a

VACANTLOT

EMITSSURPLUS SHOES

CEILINGS INC.AARCQ RADIATORS

. dWBlATORREPAIR SHOP)

VACANTLOT

15TH

CHICAGOSUPPLY CO

(INACTIVEWAREHOUSE)

SAWYERLUMBER<LUMJERSTORAGE

VARK>

AVENUE

AUTOTRUCK PARTSWAREHOUSE

KIRSHBAUMAND KRUPP

AVENUE

MARTINBUSH

(ACTIVESCRAPMETAL

AVENUE

VACANTLOT

ONACtlVCSCRAP METALPROCESSING)

SCRAPCO

AVENUE

BAKERPLUMBING

ANDPUMP

WAREHOUSE

SAWYERLUMBER

YARJ&

KIRSHBAUMAND KRUPP

(ACTIVE SCRAPMETAL PROCESSING)

RECEIVINGVARB

SAM BLOOMIRON ANDMETAL

(ACTIVEMETAL PROCESSING)

VACANT •- - -

14TH AVENUE

NORTH

200

SCALE IN FEET

FIGURE 2-2LOCAL AREA MAP

UNION SCRAPMINNEAPOLIS, 'MINNESOTA

PROJECT NO.

11-89-185DATE

8/28/89

PREPARED IY

ERN/DD DeltaEnvironmentalC«nMiltant«, Inc.

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolit, MinnesotaDelta No. ll-W-185Page3

2.13 Geological Investigation

The RI field work activities included the completion of a geologic investigation designed to characterize

the geologic conditions and materials beneath and adjacent to the site. Specifically, the geologic

investigation was to provide information on subsurface stratigraphy, sediments and bedrock necessary to

evaluate vadose zone and saturated zone migration of water and contaminants. This work consisted of

the following activities:

• Compilation and review of available well logs from the Minnesota Geological Survey (MGS) withina one mile radius of the site and preparation of geologic cross sections based on the well logs andthe review of available geologic literature.

• Completion of 23 soQ borings using hollow stem auger, mud rotary, and combined hollow stemauger and mud rotary drilling methods. Collection of soil samples for lithologic description andphysical testing by split spoon and lined spoon sampling techniques at various intervals and depth*.

The following sections present specific activities carried out to complete the geologic investigation.

2.1.3.1 Edstlnt Ground Water WeB Review

A well log search conducted at the MGS, identified the locations of 33 wells present within a one mile

radius of the site (Table 2-1). Two geologic cross sections have been prepared for the purpose of defining

the regional glacial and bedrock stratigraphy. Figure 2*3 presents the locations of the two cross sections,

A-A' and B-B'. Figures 2-4 and 2-5 present the cross sections A-A* and B-B', respectively. Copies of the

33 well logs are located in Appendix R

2.1.3.2 Soli Borints

Twenty three (23) soil borings were completed both oa and off site. The following discussions present•

specific information on the number, locations, depths, and sampling for each type of boring completed

during RI field work.

1.1.3.2.1 General Drilling. Sampling, and Classification Methodologies

Twenty one (21) of the 23 soil borings were completed using hollow stem anger (HSA) drilling techniques

incorporating split spoon sampling by standard penetration methods (ASTM D1586-7). For this project,

the split spoons were hammer driven through a 24 inch interval Twelve of the soil borings were on-site

shallow borings completed between 12 feet and 17 feet in depth using a continuous split spoon sampling

TABLE 2-1

Summary of Local WeD Logs Vicinity of Union Scrap SiteMinneapolis, Minnesota

Delta No. 1149-185

UniqueWell #

151591151600200255200265200266200267200268200269200270200271200348200349200350200353200588200589200590200593200609200610200611200612200615200616223722223995226101232307234562236155240632241275.'429308

T/R/S

29-24-22 ABBC-24-24-22 ABBC-29-24-10 DDBDBA29-24-14 BBBBAC29-24-14 BDBCB-29-24-15 ADDCBD29-24-15 ADCDCB29-24-15 ADCDBD29-24-15 BCBCCC29-24-15 CAACCB29-24-22 BCBBAA29-24-22 BBCDDD29-24-22 BBBDDB29-24-22 CACBCB29-24-10 DCBABA29-24-10 CCBACD29-24-15 BDBDCD29-24-16 BADBAB29-24-14 DDCBCD29-24-15 CDCBCA29-24-15 BCCDAA29-24-15 DADDDA29-24-22 ABCCBD29-24-22 DBBD-29-24-15 BDBDBB29-24-22 BAAABD29-24-16 CABD-29-24-11 CCCCDC29-24-15 ADBDBB29-24-09 DCDCCA29-24-10 DDBBDC29-24-22 CAABBB29-24-22 CAAB-

Date

19861986NA19341948193819621951NA195719591969NA195219301909NA1912NANANA19551932NA1972190119241933NANANA1939NA

Hrrlmtcvn

827827823834835815810812842825830835835845812871830895838828834815835840834835869834818890826820822

i Depth(Feet)

3803806756503177009517096751313753642233776082107102321318536015238330793033021862630540957530154

DepthTo Water

5140NANA604352NANA1560497877NA50NA71NANANA4044NA4514353548NA172312

ElevationWater

776787NANA775772758NANA810760791757768NANA821824NANANA775791NA790821799799770NA809797798

DevelopedFormation

Ostp-OpdcOpdc-OjdnUnknownOpdc-CjdnOpdc-CjdnOpdc-CmtsCmtsOpdc-CmtsOpdcPLT»Opdc-CjdnOpdc-CjdnPLTiUnknownUnknownOstp-OpdcUnknownUnknownUnknownUnknownUnknownUnknownUnknownUnknownCmtsOstp-CjdnOstp-OpdcUnknownOpdcOpdc-CjdnUnknownOpdc-CjdnPLTs

NGVD • National Geodedic Vertical DatumT/R/S - Township, Range, SectionNA - Information not availableOstp • Ordovician St Peter SandstoneOpdc - Ordovician Prairie du Chien GroupOjdn -Ordovician Jordan SandstoneCmis - Cambrian ML Simon SandstonePLTS - Unconsolidated Sands and GravelsSource: Minnesota Geological Survey - Well Log Data Base

1*6101 . MINNESOTA UMQUE WELL NU

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SCALE IN FEET

FIGURE 2-3GEOLOGIC CROSS SECTION

LOCATION MAPUNION SCRAP

MINNEAPOLIS, MINNESOTAPMOJCCT NO.

10-89-185BATE

6/26/89

PREPARED BY

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MOJCCT NO. nen11-89-185 BDC

M1E MCW<

6/29/89 ^>

SANDS AND GRAVEL

CLAY

DECORAH PUTTEVnXEGLENWOOD FORMATIONS

ST. PETER SANDSTONE

PRAIRIE OU CHIEN GROUP

ELEVATION OF BOTTOM OF WELL

DATA UNAVAILABLE

INFERRED CONTACT

URE 2-4SECTION A - A'ON SCRAP)LIS, MINNESOTA

MO> IT

(/PR A

Jr ^KnL Cn«kMMn«ntalm) B///m. CenMltonto. Inc.

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FIGURE S-5CROSS SECTION B - B'


MIOJECT NO.

11-89-185DATA UN

6/30/89

PREPAK£D §T

BDO/PR 0«l»oenvironmentalCensuKanta. Inc.

Remedial Invotintion ReportUoioo Scnp Iron and Meul Company1608 Wasbin|toa Avenue NorthMinneapolis, MinoetouDelu No. 11-89-185Page 4

interval through a 3.25 inch interior diameter (ID) HSA. Three and one quarter inch LD. HSA was used

only where the soil borings were not completed a* monitoring wells. Three additional deeper soil borings

completed to between 57 feet and 67 feet abo wed 125 inch LD. HSA. These were completed using a

five foot split spoon sampling interval due to the greater completion depths. The remaining six soil

borings were completed using 4.25 inch LD. HSA with split spoon samples collected at five foot intervals.

Boring B-13A required the use of mud rotary drilling techniques using a non-bentonite, biodegradable

drilling mud (REVERT) and a 1875 inch tiicone ML The alternate drilling method was required due to

substantial "blow up* of sand into the HSA alter penetrating the water table. The blow up of sand into

the HSA hampered the collection of split spoon samples within the HSA. The split spoon sampling was

continued once the switch over to mud rotary was made.

The remaining two soil borings were deep litholofy borings completed to 196 feet and 98 feet Both were

completed utilizing mud rotary drilling technique*, REVERT as the drilling fluid additive and either 12

inch or 7.875 inch tricone roller bits. Split spoon samples were collected at 10 foot intervals using a

wire line sampling mechanism as described in Section 2.1.3.22.

All split spoon samples were visually classified ia the field by the drill crew chief and the Delta geologist

Portions of the split spoon samples, except those from the 12 shallow soil borings were placed in jars and

later described according to ASTM D2487. The boring logs for all 23 soil borings are located in Appendix

L

All soil borings not completed as monitoring weDl were abandoned by grouting using portland cement

The grout was trended through the HSA if the boring penetrated the water table and was poured from

the surface for the 12 shallow soil borings. The deep mud rotary boring was pressure grouted from the

base to the surface.

2.L3.2.1 T>*o Sell Bortnti

Five deep soC borings were completed as part of the RI Geld investigation. The purpose of three of the

deep borings (B-7C, B-13A, and B-14A) was to define the depth and orientation of the first clay layer

greater than 10 feet in thickness. A fourth deep boring, B-14B, was completed to define stratigraphy down

to bedrock. A fifth boring, B-14C, was completed to collect a sediment sample from beneath the clay

Remedial Invitation ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Pafe 5

layer and provided a borehole for deep well installation. The locations of these five borings are presentedin Figure 2-6.

The three clay definition borings were completed by Geotechnkal Engineering Corporation (Geotech)

using a Mobile Drill Company B-57 HSA rig. Splh spoon sampling was conducted at five foot intervals

in all three borings. Boring B-14A located northwest of the site was the first deep boring completed.

This boring was completed using 3.25 inch LD. HSA and mud rotary drilling techniques. A clay layer was

observed beginning approximately 43 feet below the surface and continued for at least 14 feet to the

boring termination depth of 57 feet The HSA was used to a depth of 40 feet with mud rotary from 40to 57 feet This was required due to blow op of sand as discussed in Section 2.132.1, General Drilling,

Sampling, and Classification Methodologies.

A brass tube lined, 15 inch split spoon was used to collect an undisturbed sample of the clay unit in B-14A. The sample was collected from between 55 feet and 57 feet below the surface. This sample was

submitted for laboratory analysis to determine the vertical permeability, moisture content, and particle

size distribution.

The second clay definition boring was B-13A located southwest of the site across 16th Avenue as shown

on Figure 2-6. The clay layer was observed at a depth of 45.5 feet below the surface and continued to

the boring termination depth of 61 feet HSA was the only drilling method used in this boring.

Precautions were taken to minimize sand blow up aad permitted the continued advancement of the HSAand collection of representative split spoon tarnpkt for Uthologk description. These precautions consisted

of adding water from the city of Minneapolis water system to the interior of the HSA to maintain a

vertical head of water within the HSA. This prevented sand from entering and rising in the auger.

The third clay definition boring, B-7C, was completed on the east central edge of the site as shown on

Figure 2-6. HSA drilling methods along with the addition of water to prevent blow up, as discussed above,

was used to advance the boring. The clay unit was encountered at a depth of 51 feet below the surface

and was observed until the boring termination depth at 67 feet Split spoon samples had been collected

previously at five foot intervals in B-7A bom the surface to 42 feet Split spoon samples were collected

from B-7C at five foot intervals from 45 feet to 67 feet

B-14A*

B-14B •

B-14C

GRASSYAREA

4, „

a

v><c

SIGNE - 2 STOP


B-7C

HYDRANT

16TH AVENUE

LEGENDFENCERAILROAD TRACK

LIGHT POLE

UTILITY POLE

DEEP SOIL BORING LOCATIONS

B-13A

NORTH

40

SCALE M FEET

FIGURE 2-6DEEP SDIL BDRING LDCATIDNS


PROJECT NO.

11-89-185CATC

8/88/89

PREPARED VT

MVM/PRBIT Delta

Remedial Investigation ReoonUnioo Sertp Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149-185Page 6

The fourth deep boring was designed to be completed to the first bedrock unit encountered. This boring,B-14B, was completed by Thein Well Company (Thein) using a EWBANKS-51 drill rig. 7.875 inch rotary

bit and mud rotary drilling techniques. This boring was located approximately 10 feet south of B-14A asshown on Figure 2-6. It was advanced directly to the termination depth of 196 feet As the boring was

advanced, samples were collected from the drilling fluid as it circulated through the hole using a straining

screen. The borehole was cleaned of cuttings at various intervals by allowing circulation of the drilling

fluid without advancing the drill stem. This allowed for the collection of more representative samples as

drilling progressed. Bedrock was encountered at 192 feet below the surface and was penetrated four feet

to insure proper identification. After reaching the termination depth of 196 feet, the hole was cleanedand the drill stem removed.

Soil samples were collected from the sides of the muddled borehole utilizing a split spoon sampler and

specialized, direcUonally diverting drive shoe. This allowed the split spoon sampler to be driven at an

angle into the side of the borehole. A three inch diameter, low carbon steel casing, equipped with the

diverting drive shoe device at the base, was set 180 feet into the borehole. The diverting device allowed

for the collection of split spoon samples driven with a wireline operated, downhole hammer. The spoon

and hammer were lowered down through the three inch casing until reaching the diverter at the base.

The diverter then angled the spoon, which was equipped with a series of joints, into the side of theborehole at a 20 degree angle. The hammer was then operated by the wireline to drive the spoon into

the formation. Samples were collected at ten foot intervals from 180 feet upward. After collection of

a sample the diverting device was raised 10 feet and the next sample collected. Samples were collected

at Gve foot intervals from 90 feet up to 80 feet for better definition of the base of the day layer.

Sampling was discontinued at 60 feet, three feet below the termination depth of B-14A at 37 feet»

The final deep soil boring was B-14C as sbowa oa Figure 2-6. A deep aquifer monitoring well was

completed in this boring. After completion of B-UA and B-14B, the entire nnconsolidated stratigraphy

was known at this location, B-14A identified a day layer approximately 43 feet below the land surface.

B-14B identified the base of the clay at approximately 84 feet below land surface. Consequently, B-14C

was advanced to approximately 14 feet below the bate of the clay layer. B-14C was completed using a

12 inch diameter drill bit from the surface to a depth of 55 feet, 12 feet into the clay. An eight inch

surface casing was then installed into the 12 inch borehole. A 7.875 inch roller bit was then used to

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinoeapoli>, MinnesotaDelta No. 1149-183Pa|e7

complete the hole from 55 feet to the termination depth of 98 feet An effort was made to collect a

lined split spoon sample for grain size analysis from 96 feet to 100 feet However, the sample could not

be collected due to a boulder or very coarse gravel at the base of the borehole. Upon completion of the

boring, monitoring well MW-14d was installed. Monitoring wells and the ground water investigation are

discussed further in Section 2.1.5, Ground Water Investigation.

2.1.3.23 Water Table WcB Borings

Six water table well borings were completed as part of the RI Geld activities. The purpose of these

borings was to provide lithologic information and provide a suitable borehole for monitoring well

installation. The locations of these borings are shown on Figure 2-7. The borings were completed by

Ceotech using either their Mobile B-57 or CME-550 drill rigs. The borings were completed using 4.25

LD. inch HSA and were advanced approximately 10 feet into the water table. Split spoon samples were

collected at five foot intervals from four of the six locations. These four locations were B-3A, B-7A, B-

10A, and B-15. Boring locations B-14D and B-13B had samples collected previously (B-14A and B-13A,

respectively) during completion of the clay definition borings. Consequently, these two borings were offset

approximately 5 feet from the clay definition borings and advanced approximately five feet into the

observed water table. At that point in all six borings, a split spoon sample was collected and the sediment

submitted for particle size distribution testing. The borings were then advanced another five feet into the

water table. The termination depths of these borinp varied from between 40 feet to 43.5 feet below the

surface depending upon the observed water table elevation. Abo, water was added at each location to

prevent sand blow up into the HSA bore which woold have prevented proper installation of the screen

and filter sand pack. Installation of monitoring wells in these borings is discussed further in Section 11.5.

«

Shallow Sofl

Twelve shallow sofl borings were completed on site at part of the RI field activities. The purposes of

these shallow soil borinp were to collect shallow sofl samples for chemical and physical analysis and to

determine the shallow vadose zone stratigraphy. The locations of these borinp are shown on Figure 2-

8. The borinp were completed by Geotech using either a CME-550 or CME-55 auger rigs.

The interface between the fill or native sand and the clean backfill material used during the Emergency

Actions was generally a well defined boundary and was observed between 1.0 foot and 3.5 feet below the

LEGEND• - "- FENCE

^ — I — I- RAILROAD TRACK

Ofa

I

a

in<

SIGNE - Z STOP


.B-10A

B-7A

B-3A,

HYDRANT

-I-16TH AVENUE

B-15

B-I3B

O LIGHT POLE

* UTILITY POLE

WATER TABLE WELL* SOIL BORING LOCATIONS

tSCM£ M FEET

FIGURE 2-7WATER TABLE VELL

SOIL BORING LDCATIDNSUNION SCRAP

MINNEAPOLIS, MINNESOTANO.

11-89-185DATE

8/28/89

PREPARED 91

MVM/PR

BY DeltaCnvtn n«alCenwiHanli. Inc.

4,

,4, si/

GRASSY

AREA

LEGEND

-— •— FENCE

Ofa

u

aI—II

I—I- RAILROAD TRACK

O LIGHT POLE

f UTILITY POLE

O SHALLOW SOIL BORING LOCATION

SIGN

HYDRANT

-t-

E - Z STOPCONVIENIENCE STORE

PARKING LOT

B-10B

B-5O

B-7B

B-3B

B-8

8"2

16TH AVENUE•I-

-• • * H • »

0

-*-•

_L

tSCALE M FEET

FIGURE E-8SHALLOW SOIL BORING LOCATIONS


PROJECT NO.

11-89-185DATE

8/38/89

PREPARED BY

MVM/PRREMMU) BY

•SLDeltaCwimltanto. Ina.

Remedial Invettlntton ReportUnion Scnp Iron tad Metal Company1606 WMbinpoo Avenue NorthMinneapolis, MinnesotaDelta Na 11-89-185FafeS

surface. The definition of this interface was very critical because it determined the depth at which the

chemical sampling protocol was initiated. The interface was visually identified by an abrupt change inlithology, usually within the first split spoon sample taken. Once the interface was identified, twoconsecutive split spoons were taken and sofl samples collected for chemical analyses. These samples are

identified as shallow and intermediate soil sampka. The next two continuous split spoons were used for

lithologk classification. A deep soil sample was collected from the next spoon for chemical analyses. This

sampling sequence was completed for all 12 of the shallow soil borings. A generalized schematic showing

shallow soil boring sampling intervals is presented as Figure 2-9.

At four locations, B-l, B-8, B-ll, and B-12 an additional lined spoon sample was collected one foot below

the last split spoon sample collected for chemical analyses. These samples were submitted for tests for

vertical permeability, moisture content, and particle sixe distribution.

Chain of Custody (COC) procedures were followed for the collection and handling of all of the physical

sofl samples. The COC form was initiated by the Delu geologist upon collection of the sample. The

samples were relinquished to the Delta sample custodian until completion of the field work, at which time

they were transported to Braun Engineering and Testing and relinquished for completion of the physical

analyses.

1.1.4 Soil and Vadose Zone InvesHaatioo

The soil and vadose zone investigation field activities were designed to evaluate the nature and

approximate lateral and vertical extent of any remaining soil contamination. This portion of the RI fieldactivities focused 00 the old fill material and natural soils located beneath the base of the new fill brought

in following the EPA Emergency Removal Action in November and December 1988. It was assumed the

imported backfill material was free of contamination and therefore these cover materials were not

evaluated during this investigation.

The 12 sofl boring locations used for the soO and vadose zone investigation are presented in Figure 2-&

Three predetermined intervals were chosen for the collection of sofl samples for chemical analyses. The

sampling intervals are shown on Figure 2-9 and are referred to as:

MATERIAL DESCRIPTIONSHALLOW SOILBORING LOCATION

2 —

6 -

a -

10 -

11 -

12 -

SHALLOWSOL

SAMPLE

MTERMEDIATEsot.

SAMPLE

umoLoerSPLIT

SPOONSAMPLE

UTHOLOGYSPUT

SPOONSAMPLE

DEEPSOIL

SAMPLE

BASESOIL

SAMPLE

INTERFACE

FILL ORNATURALSEDIMENT

FIGURE 2-9GENERALIZED SHALLOW

SOIL BORING SCHEMATICUNION SCRAP


PMMCCT NO.

10-89-185DATE

8/28/89

PREPARED BV

MVM/PRD«HoEnvironmentalConsultant*. Inc.

Remedial Invotintioo ReUnion Scrip Iron and Metal Company1606 WaduojtoQ Avenue NorthMinneapolis MinnesotaDelta No. 11-89-185Page 9

• Shallow soil sample • first split spoon sample below backfill

• Intermediate soil sample - split spoon sample immediately below shallow chemical sample.

• Deep soU sample - fifth continuous split spoon sample below backfflL

The chemical samples were collected by split spoon sampling technique. During sample collection, themost critical delineation was determining the interface between the new fill and the underlying old fill or

native sand. Fortunately, this boundary was generally distinct and was identified between 1.0 foot and

3.5 feet below the surface. The chemical sampling sequence was initiated after identifying the interface.

A specific sampling sequence was followed during the collection of all 36 soil samples which were

submitted for chemical analysis. After the split spoon was driven 24 inches, it was removed from the HSA.

The split spoon was opened and immediately screened by the Delta geologist for volatile organics using

an hNu photoionization detector. Immediately after that, a sample for VOC analyses was collected where

required. This sample was collected from a discrete zone identified as being the most accessible to be

quickly inserted into the sample jars. The remaining sample was then homogenized in a large, stainless

steel mixing bowl using a stainless steel spoon. Once the soil was completely mixed, the remaining sample

containers were filled. A separate steam cleaned split spoon, mixing bowl, and spoon was used for each

of the shallow, intermediate and deep chemical samples. All sampling equipment was thoroughly steam

cleaned between borings. This included the back of the rig, the drilling angers, split spoons, wrenches,

drill stem and center plug, and all of the Delta sampling utensils.

After a sample was collected and placed into the sample containers, the Delta geologist completed the

sample identification labels, the sampling information form, and completed and initiated the COC form.

Once all labelling was completed, the Delta geologist relinquished the forms and samples to the sample

custodian who brought the samples through a decontamination line where they were rinsed with soapy

water, then deionized water, dried and the label! attached to the appropriate sample container. The

samples were then logged in by sample identification number by the sample custodian and placed into a

cooler containing ice. At the end of each day, the samples were either relinquished to another Delta

employee or maintained by the sample custodian and transported to PACE Laboratories where the COC

was transferred to the receiving PACE personnel

Remedial Invenlotion ReportUnioo Scrap Iron and Metal Company1606 Wtihingtoo Avenue NorthMinneapolis, MtaoeeotaDelta No. 1149-185Page 10

During the completion of the shallow soil borings and chemical sample collection, an x-ray fluorescence

spectrometer and operating technician from the Minnesota Pollution Control Agency (MPCA) were

present at the site. The x-ray fluorescence spectrometer is a transportable Geld instrument used to screen

for specific metal content In this instance, the instrument was calibrated specifically for lead. Portions

of all but three of the 36 samples collected for chemical analysis were analyzed for lead content The

three samples which were not analyzed, B-3 shallow, B-S intermediate, and B-10 shallow, were locations

where field duplicates were taken and the entire SOD sample volume was used.

Upon completion of all the soil borings, the sofl cuttings were transported to a location in the northeast

corner of the site where they were deposited over plastic. At the end of each day, the pOe was covered

with weighted plastic to prevent infiltration of rain water and wind erosion. Composite samples have been

collected of the cuttings and analyzed for PCB» and EP Toxicity method teachable metals.

2.1.4.1 Shallow Chemical Sameley

Shallow chemical samples were collected at all 12 boring locations. The depth of these samples was from

0.0 to 10 feet beneath the interface. Six of the 12 samples were submitted for chemical analyses for the

Target Compound List for organic* (TCL) (Table 2-2) and Target Anaryte List for inorganics (TAL)

(Table 2-3). The remaining six samples were submitted for chemical analyses for a short list of

parameters. Table 2-4 presents the short list of parameters. The short list parameters includes soil

analyses for PCBs and total and EP Toxidty Methods for metals. In addition, all soil samples were

laboratory tested for pR Figure 2-10 presents the locations for the 12 shallow soil samples and the six

samples which were submitted for the TCL/TAL analyses. These six locations, B-2, B-3B, B-4, B-5, B-

6, and B-7B, were chosen because previous sampling showed elevated levels of contaminants in that area

and/or it is an area where extensive site operations occurred. Table 4-1 is a summary of all soil samples

that were collected for chemical analysis. The information in Table 4-1 includes sample identification

number, depth interval below surface, and actual elevation interval

2.1.4.2 Intermediate Chemical Samples

The intermediate chemical samples were collected at all 12 boring locations with all 12 samples being

submitted for the short list analyses and laboratory pH. The intermediate samples were collected from

10 to 4.0 feet below the interface. Figure 2-11 presents the 12 intermediate sample locations.

TABLE 2-2

Target Compound List (TCL)Union Scrap Iron and Metal Company

Minneapolis, MinnesotaDelta No. 1149-185

Volatlles

ChloromethaneBromomethaneVinyl chlorideChloroethaneMethylene chloride

AcetoneCarbon disulfide1.1 - Dichloroethene1.1 • Dichloroethane1.2 - Dichloroethene (total)

Chloroform1,2 - Dichloroethane2 • Butanone1.1.1 • TrichloroethaneCarbon tetrachloride

Vinyl acetateBromod ichloromethane1,2 • Dichloropropanecis - 13 - DichloropropeneTrichloroeihene

Dibromochloromethane1.1.2 - TrichloroethaneBenzenetrans - 13 - DichloropropeneBromoform

4 •* Methyl 1 • 2 • pentanone2 • HexanoneTetrachloroetheneToluene1.1A2 • Tetrachloroethane

ChlorobenzeneEthyl benzeneStyreneXylenes (Total)

74-87-374-83-975-01-475-00-375-09-2

67-64-175-15-075-35-475-34-3540-59-0

67-66-3107-06-278-93-371-55-656-23-5

108-05-475-27-478-87-510061-01-579-01-6

124-48-179-00-571-43-210061-02-675-25-2

108-10-1591-78-6127-18-410848-379-34-5

108-90-7100-41-410O42-51330-20-7

101010105

105555

551055

105555

55555

1010555

5555

Contract Required Detection Limit

CAS Number WaruBi Low-Soil ue/Rg

101010105

105555

551055

105555

55555

1010555

5555

Table 2-2 ContinuedPage 2Delia No. 11-89-185

Semlvolatlles

Phenolbis (2-Chloroethyl) ether2 • Chloropbenol1.3 - Dichlorobenzene1.4 • Dichlorobenzene

Benzyl alcohol1,2 - Dichlorobenzene2 • Methylphenolbis (2 - Chloroisopropyi) ether4 • Methylphenol

N • Nitroso-di-n- dipropylamineHexachloroe thaneNitrobenzeneIsophorone2 - Nitrophenol

2,4 - DimethylphenolBenzoic acidbis (2 - Chloroethoxy) methane2,4 • Dichlorophenol1,2,4 • Trkhlorobenzene

Naphthalene4 - ChloroanilineHexachlorobutadiene4 • Chloro • 3 • methytphenol(para-chloro-meta-cresol)2 • Methylnaphthalene

Hexachlorocycloentadiene2,4,6 • Trichlorophenol2,4^ • Trichlorophenol2 • Chloronaphthakae2 • Nitroaniline

DimethylphtbalateAceaaphtykne2j6 - Dinitrotoluene3 • NitroanilineAceaaphtheoe

Contract Required Detection LimitCAS Number Wfcruri Low Soil ue/ke

108-95-2111-44-495-57-8541-73-1106-46-7

100-51-695-50-195-48-7108-60-1106-44-5

621-64-767-72-198-95-378-59-188-75-5

105-67-965-85-0111-91-1120-83-2120-82-1

91-20-3106-47-887-68-359-50-7

91-57-6

77-47-48846-295-95-491-58-788-74-4

131-11-3208-96-8606-20-299-09-283-32-9

1010101010

1010101010

1010101010

1050101010

10101010

10

1010501050

1010105010

330330330330330

330330330330330

330330330330330

3301600330330330

330330330330

330

33033016003301600

3303303301600330

Table 2-2 ContinuedPage 3Delta No. 11-89-185

SemlvolaUles

2,4 - Dinitrophenol4 - NitrophenolDibenzofuran2,4 - DinitrotolueneDiethylphthalate

4 • Chlorophenyt • phenyl etherFluorene4 • Nitroaniline4,6 - Dinitro - 2 - methylphenolN - Nitrosodiphenylamine

4 - Bromophenyl - phenyletherHexachlorobenzenePentachlorophenolPhenanthreneAnthracene

Di - n - ButylphthalateFluoranthenePyreneButylbenzylphthalate33* - Dichlorobenzidine

Benzo(a)anthraceneChrysenebis (2 • Ethylhexyl) phthalateEH - n - octylphthalateBenzo (b) fluoranthene

Benzo (k) (luorantheneBenzo (a) pyreneIndeno (1,2\3 - cd) pyreneDibenz (aji) anthraceneBenzo (|JM) perykne

Peitldde«/PCB«

Aroclor • 1016Aroclor • 1221Aroclor - 1232Aroclor • 1242Aroclor -1248

Aroclor - 1254Aroclor • 1260

CAS Number

51-28-5100-02-7132-64-9121-14-284-66-2

TO05-72-386-73-7100-01-6534-52-186-30-6

101-55-3118-74-187-86-585-01-8120-12-7

84-74-2206-44-0129-00-085-68-791-94-1

56-55-32184)1-9117-81-7117-84-0205-99-2

207-08-950-32-8193-39-553-70-3191-24-2

12674-11-211104-28-211141-16-553469-21-912672-29-6

11097-69-11109642-5

Contract Required Detection LimitLow Soil ue/kg

16001600330330330

33033016001600330

330330 .1600330330

330330330330660

330330330330330

330330330330330

80.080.080.080.080.0

160.0160.0

5050101010

1010505010

1010501010

1010101020

1010101010

1010101010

O5<X5O50.505

1.01.0

Target Anatyte Lift tor Inorganics (TAL)UnJon Scrap Iron and Metal Company

Minneapolis, MinnesotaDelta Na 1149-185

Analvte

AluminumAntimonyArsenicBariumBerylliumCadmiumCalciumChromiumCobaltCopperIronLeadMagnesiumManganeseMercuryNickelPotassiumSeleniumSilverSodiumThalliumVanadiumZincCyanide

Contract Required Detection Limit fug/1)

2006010

20055

50001050251003

500015O240

5000510

500010502010

Uw.719

TABLE 14

Short List Target for Soil SamplesUnion Scrap Iron and Metal Company


Organ Ics • PCBs Contract RequiredQuantification Limits

Aroclor •Aroclor •Aroclor •Aroclor -Aroclor •Aroclor •Aroclor •

1016122112321242124812541260

80.080.080.080.080.0160.0160.0

Inorganic • Metals

ArsenicCadmiumChromium

CopperLead

MercuryNickel

Of/1

10510253

0.240

klw.807

*

V

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NORTH

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PARKING LOT

B-10B

B-5

B-7B

B-3B

B-2 B-6

16TH AVENUE

40

SCALE IN FEET

FIGURE 2-10SHALLOW CHEMICAL

SOIL SAMPLE LDCATIDNSUNION SCRAP

MINNEAPOLIS, MINNESOTAHUMECT NO.

11-89-185DATE

8/21/89

PREPARED BT

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4, 4,

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r 16TH AVENUE r •

0 0 0

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* FIGURE 2-11INTERMEDIATE CHEMICAL

SCALE M FEET


MINNEAPOLIS, MINNESOTAMOJCCT NO.

11-89-185DATE

8/E1/89

PREPARED BT

MVM/PR DeltaE nvf ra nmcnfolConsultant*. Inc.

Remedial Investigation ReportUnion Scrap Iron and Meul Company1606 Washington Avenue NorthMinneapolis, MinncarnaDelta No. 1149-185Page 11

2.1.43 Deep Chemical Samntea

The deep chemical samples were collected at all 12 boring locations with 8 of the 12 samples being

submitted for the short list analyses. The Tg»"""!fag four samples were analyzed for the TCL/TAL All

samples were also tested for laboratory pR The locations of the deep chemical samples and the four

which were submitted for TCL/TAL, B-2, B-3, B-5, and B-7, are presented in Figure 2-12. The deep

samples were collected from 8.0 to 10.0 feet beneath the interface.

2.L5 Groond Water Investigations

The ground water investigation portion of the RI field investigation was designed to:

• Evaluate the hydrogeologic conditions immediately beneath and within 100 feet of the site.

• Evaluate ground water quality.

• Evaluate the potential of ground water as a pathway for migration of contaminants originatingfrom the site.

To accomplish these goals, seven ground water monitoring wells were installed on and adjacent to the site.

Six of the wells are water table monitoring wells with the seventh a deep aquifer monitoring well Figure

2-13 presents the locations of the seven monitoring wells. All monitoring wells were installed and

completed according to the Minnesota Department of Health Water Well Codes, Chapter 4725.

2.1.5.1 Water Table MonltoriM WtUs

As shown on Figure 2-13, three water table monitoring wells MW-3, MW-7, MW-10 were installed on site.

Two additional wells, MW-13 and MW-15, were installed south of the site across 16th Avenue and a sixth

water table monitoring well, MW-14*, was installed west of Washington Avenue, northwest of the site.

The six water table monitoring wells were constructed of two inch diameter, 15 foot stainless steel screens

connected to a two inch diameter, low carbon riser using a stainless steel coupling. The 15 foot screens

were all O010 inch slot Johnson continuous wire wrapped screens. The screens were installed

approximately 10 feet into the saturated zone. The filter pack set around the screen consisted of a #30

size Red Flint from the base to two feet above the screen. An additional two foot layer of a graded #45

• #55 Red Flint sand was then placed above the #30 sand. The increased sand pack height was added

to decrease the chance of having grout migrate down around the screened area. The remaining annular

4* 4?

-4,

GRASSY

LEGEND

»- FENCE

Qta

u

aa

I—^ RAILROAD TRACK

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• DEEP SAMPLE LOCATION (TCL/TAL)

SIGN

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B-l

HYDRANT

t


PARKING LOT

B-10B

B-5

B-9

B-3B

B-8

B-8 B-6

16TH AVENUE

B-ll

B-7B

B-12

SCAl£ M FtET

FIGURE 2-12DEEP CHEMICAL


MINNEAPOLIS, MINNESOTAPHOJCCT NO.

11-89-185DATE

8/21/89

PKPAMCD rrMVM/PR

DeltaCnvtrennwntolCanwltante. Inc.

MV-14S

GRASSY

40

a

a

U)<£

U

SIGNE - Z STOP

CONVENIENCE STORELOT

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-t-16TH AVENUE

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LEGEND—« »- FENCE-I—I—I- RAILROAD TRACK

O LIGHT POLE

0 UTILITY POLE

fc MONITORING WELL LOCATION

HI N

MW-15

NORTH

FIGURE 2-13MONITORING WELL LOCATION MAP


HIOJGCT NO.

11-89-185

7/31/89

PMPAMCD BT

MVM/PR

/ Deltatn«tr>n«v«niolCenMiltonto. hw.

Remedial Invention ReportUnion Scrip Iron and Metal Company1608 Wathington Avenue NorthMinneapolis Minne*ouDelta No. 1149-185Pa|e 12

space was grouted using portland cement A locking protective casing was set with concrete over the two

inch riser and three steel protective bumper potts were emplaced on a two foot radius from each well

1.1.5.2 Deep Aoulfer MonltortM WeB

As described in Section 2.132 - Soil Borings, the deep aquifer well, MW-144, was completed west of

Washington Avenue, northwest of the site (Figure 2-13). The deep aquifer well was installed in the sand

and gravel unit encountered beneath the clay layer. The well was completed to a depth of 98 feet below

the surface using a Ove foot long 4 inch diameter t*yfpV*« steel, 0.010 slot Johnson screen. The screen

was welded to a 10 foot long section of 4 inch Afaff**r stainless steel riser. The remaining 85 feet of

riser consisted of 20 foot sections of four inch diameter, low carbon steel pipe welded at the joints. The

four inch riser and screen was set through an eight inch surface casing which was installed to a depth of

55 feet into a 12 inch diameter borehole. The eight inch surface casing was required due to the

penetration of the clay aquitard. The sand pack set around the screen was a #30 Red Flint and was

brought five feet over the top of the screen. The remainder of the annular space of the borehole or eight

inch casing and the four inch riser, and the annular space between the eight inch surface casing and the

12 inch borehole were grouted to the surface using portland cement A locking well cover which enclosed

the four inch riser was placed on the eight inch surface casing and three steel bumper posts were set on

a two foot radius around the well.

2.1.5.3 Well DevetomneiU

The development of the six water table wefls was completed by Precision Environmental Services, Inc.

(Precision) on August 4,1989. Specific weD development information is presented in Appendix J. The

development procedure involved pumping and surging the well using a QED airlift pump to remove any

Cite sediment which had accumulated in the well and to develop the sand pack. After the majority of the

fines had been removed, a 1.75 inch Grundfos MP-1 electric submersible pump was used to further develop

the sand pack and remove a greater volume of water. The MP-1 was operated until a minimum total

volume of 100 gallons had been purged from each well The initial sediment-loaded water was allowed

to settle in 55 gallon drams prior to being discharged to the sanitary sewer. The accumulated sediment

was then placed on the soil cuttings pile.

Remedial Investigation ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149-185Pafe 13

Three composite samples from the cutting! pfle were analyzed for PCBs and EP Toxicity (teachable)

metals. No detectable leveb of PCBs or teachable metals were found.

The development of the deep aquifer monitoring well was completed by Thein using a pressurized water

jetting tool The wefl was then surged and pumped using an air flow rate of approximately 100 cubic feet

per minute for 100 minute*. A total of 1,500 gallon of water was purged during development The water

was clear upon completion. The water was footed through a settling trough prior to being discharged to

the sanitary sewer.

2.LS.4 Ground Water Sampling

Ground water samples were collected by PACE Laboratories from the seven monitoring wells on two

separate occasions. A third confirmation round of ground water samples was collected from the water

table monitoring wells MW-7, MW-10, and MW-15 on September 19. 1989.

The first two rounds of samples were collected by stainless steel bailer after completion of a well

stabilization test The well stabilization tests for the water table monitoring wells involved monitoring the

ground water as it was removed from the well by bailer until the temperature, pH, and specific

conductance had reached consecutive readings that were within ± <L5 degrees Celsius, ± Oil standard pH

units, and ± 5 percent, respectively. The deep well. MW-14d, was stabilized by continuous pumping with

a submersible pump and measuring temperature, pH, and conductivity until the above criteria were met

The first round of samples were collected on August 7,1989 and the second at collected on August 10,

1989. All samples were analyzed for the TCX/TAL constituents as presented in Tables 2-2 and 2-3.

Third sampling rooad was completed by PACE Laboratories on September 19,1989. This round began

with the completion of a stabilization test conducted by bailing each well After well stabilization was

accomplished, a ground water sample was collected using the dedicated bailer and a sample collected for

PCBs analysis following EPA contract laboratory program (CLP) procedures and detection limits. An

Aqnarious II teflon lined bladder pump was then used to purge the well unto the discharge water was

visually clear and free of sediment After the water was determined to be clear, three samples were

collected over the next half boor, one initial sample, then one each 15 minutes. These samples were

collected into four liter closed atmosphere containers. The containers were equipped with a fitting that

Remedial Invotlntion ReportUoioo Scnp Iron and Metal Company1606 Wathtaftoa Avenue NorthMinoeapoiii, KfinneaouDelia No. 11-89-185Page 14

attached directly to the pump discharge hose and another that allowed air to exit the container. With

this collection procedure, the ground water samples were not exposed to the atmosphere. This same

sampling procedure was completed in order on MW-10, MW-7, and MW-15. These samples were then

analyzed for PCBs using a modified EPA Method 606 which provides for lower detection limits than the

CLP procedure. The bladder pump was dismantled and rinsed with hexane and deionized water between

2.1.5.5 Well Survey and Water Ivtfti Measurements

Upon completion of the installation of the wells. Delta surveyed the top of the riser for each well to the

top of the fire hydrant, the same vertical benchmark as discussed in Section 2.1.1 - Site Surface

Topographic and Area Mapping. This data has been tabulated and presented on Table 3-2.

Water levels in the monitoring wells have been measured, recorded, and referenced to the NGVD on six

separate occasions. Ground water elevations have been collected prior to well development, prior to each

round of sampling, prior to completion of single weO recovery tests, and on two additional occasions. The

water levels were measured using a Slope Indicator Company water level indicator which audibly indicated

when the water table had been encountered. This data has been tabulated and is presented in Table 3-

3, Mississippi River elevations at the NSP Riverside Plant (approximately 8,000 feet upstream) and the

Si. Anthony Lock and Dam #1 (approximately 7,500 feet downstream) have also been obtained from the

US. Army Corps of Engineers. The river elevation data b presented in Table 3-1.

Hvdroteologtc Field Tests

Single wen recovery tests have been conducted on each monitoring well These tests were used toestimate the horizontal hydraulic conductivity of the material in which the well is screened. These tests

«

were conducted OB August 11, 1989 with one retett conducted on August 17, 1989. Water level changes

created by the insertion of a stainless steel slug of known volume, were recorded by a pressure transducer

and data logger. This data was then analyzed to estimate hydraulic conductivity using a computer program

(Thompson, 1987). These results were compared with estimates of hydraulic conductivity based upon the

particle size distribution and the Hazen Approximation (Freeze and Cherry, 1979) (see Table 3-4). The

raw field test data is located in Appendix M.

3.» PHYSICAL CHARACTERISTICS OF THE STUDY AREA

3.1 Surface Features

3.1.1 Topography

The general area surrounding the site is comprised of a glacial till upland area to the west and the

Mississippi River Valley to the east The site is located on river terrace deposits as shown on Figure

3-1.

The till upland consists predominantly of the Superior Lobe St Croix phase terminal and end morraine

deposits. The morraine surface b gently rolling with small hills and valleys and occasional kettle lakes.

A topographic high for the area lies approximately 0.75 miles west of the site.

The site a located on post-glacial river terrace deposits that are approximately <X5 miles wide. The

deposits run parallel to the Mississippi river and east of the till upland. The terrace is relatively flat,

containing no significant topographic feature* with the exception of the road cut associated with Interstate1-94.

The Mississippi River is located approximately (X2 miles directly east and is the lowest topographic feature

in the area.

The area directly adjacent to the site b relatively flat, consistent of the river terrace on which it is located.

The primary vertical relief in the area b doe to the 1-94 road cut to the west of the site and the river

bank slope adjacent the Mississippi river to the east

The site itself b relatively flat and holds no buildings or other structures. The main surface feature b a

depression and concrete nibble pile in the northwest corner as discussed in Section 2.1.1.1, Site Surface

Topographic Mapping.

* i * Am RftCMinftlftttficc Snnrcr» IBAtita^0ftJSaJUiUIUttBIaa&SU£JiC3UMflUfei

A walking survey was conducted of the area within two blocks of the site. Because the survey was limited

to viewing the properties from off site, a detailed compilation of all processing activities, materiab stored,

and the presence of welb was not possible. The survey, however, provides a good perspective regarding

the potential environmental risk associated with the area surrounding the Union Scrap site.

The majority of the property surrounding the site has been, or b presently involved in the processing of

•crap metal Properties within the survey area which are or have been involved in metal processing are:

DESCRIPTION OF MAP UNITS

POSTGLACIAL DEPOSITSORGANIC DEPOSiTS-Peal ml organic-rich aadkmm;

rrclooVa small bodies of open waier Maay bop me tooman10 show, eapecialry within aniu <k and de

ORGANIC DEPOSITS, DRAINED AND FILLED—Organic deports largely removed prior lo filling: hKkjdeasmall mrJnined areas, hi places, loo thin lo show on iheCfOU SCCtlOns

•LACUSTRINE DEPOSITS—Sand, loamy sand, and tarn

wi* tool oonc-iick bym: ncbdef mmde bacha.In placet overlies muck or peal. L«r|e deposit in T. 29N.. R. 24 W. a chiefly thick clay, but ii overlain byareas of thick artificial fln o»cr pen dial omul be atownat the scale of ihis map. Many depoaai along takes mlbop tin are loo narrow to be shown. Ocean as fine-grained sediment beneMh lakes but is loo dim to *ow oncross axlimu

I -| FLOODPLAIN ALLUVIUM (O>YEY>—Chiefly clay mlI k J lik. commonly miied with variable imoMi of »ojr fine

und md orpnic miucr, onrlata by dick aRfficiil fill ndeveloped amu. Modi thicker to OK MMK*OU Rinr

DES MOINES LOBE AND GRANTSBURG SUBLOBEDEPOSITS (Twto Cllki Formalin)

LACUSTRINE CLAY AND SILT—LnunMed clay to rihteneraDy (en man 10 fed kick. Commonly overlie* dt,die. dB. and locaDydtt hi the rianni pan of the comty.Thin bedi of fine filly and to gravelly and oeear atbomhvief and at or near me baas fat pkcei

LACUSTRINE SAND AND SILT—Sill U medium and:contain interbedi and lenes of filty clay u (nvellyland. Coarae. gravelly und ocean locally alongbomknm. Where k a thick, can include bed. of loamyto •Hoy iiiHQitow HotnicMs

LACUSTRINE SAND AND GRAVEL— Medhjm to coneand u fine travel: may overlie coaner ooiwah admem

| OUTWASH—Sand, loamy and, and gravel: overlain byloen lea man 4 fen thick

ICE-CONTACT STRATIFIED DEPOSITS—Sand, loamyand. md gravel; locally interbedded wilh uniu du anddts, and with d*t in the eastern pan of the coonty.Cobbles and bouldco commonly preseni

GLACIAL TILL—Untoned sediment ranging from clay ubonlden. CafcareoM eicept for a leached zone eiiendingafewtatbelowikeMrface OxkUaedyellowiaktoollve

I—j —1 FLOODPLAIN ALLUVIUM (SANDD-ChM*

COLLUVIUM AND SMALL ALLUVIAL PANS—CkWIy

TERRACE DEPOSm•• LOWER TERRACE—Sml ml I

MIDDLE TERRACE—Smd. gravelly Md. •and: overlain by thin tfepood of rih. loan, or organicaedimenL Covered by Ihick anificW fill wfcere heavilydeveloped. Where terrace and b lea dm 10 feet Mck,modifiers d, •. and r denoK undeilyli Da Monet totetill, Superior tobe till, and bedrock. BooMer lap arecommon at contact wilh Superior tote tin. and where I2rii very thin, il comittt mooly of boaUer laf or anincialTill

UPPER TERRACE-Sediment fame ai middle Kfnee tMat higher elevation

LOAMY TlU -Caaafly torn ta knaara; faw ka«a aaalleaaaj af •taHaaJ MsavMac UaaMm vy Saaasrior Ma

20 bat aa «at eaam pan of *e cmary. aaal swra «m SOfeel hi ttv veMoni pvt. IsctvdBai ISMH «VQM of Aide,lav.lra.aqrcolla.taai

TILL OF MIXED COMtXKITlON-Cijaataexiv raacr-miied ydtowisii-brown u gray and reddish-tern ureddish-gray, loam to sandy loam. Reddish (111 orstratified sediment commonly within 20 feet of thesurface. Locally includes small areas of thick reddish-brown tin and thick loamy to stndy collurium Lensesof stratified sediment, primarily sand and gravel, arecommon. Included in unit dt on cross lections

RET: MEYER. G.N. AND HO68S, H.C., 198*

Mw md Mcami lenbK) by to Geography t*t*mrnniCartographic Laboratory. UnivvrMly ot UnnMola

•IS I f " "l 1

SCALE 1:100.000

FIGURE 3-1SURFICIAL GEOLOGY MAP


Remedial Involution ReportUnion Scnp Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149-185Page 2

The Martin Bush property adjoining the site to the east; the Sam Bloom property on the east side of 2ndStreet; the Kinhbaum and Knipp properties north of 17th Avenue; the abandoned lot on the corner of16th and Washington Avenues; and the abandoned lot on the corner of 16th Avenue and 2nd Street(Lockhead, 1985)(Figure 2-2). Potential contamination emanating from these sites includes battery wastes,waste oils, automotive fluids, solvents, metals, robber, and plastic products.

Two automotive parts service shops are located southwest of the site. These are the B and M Serviceand AARCO properties on Washington Avenue. B and M Service rebuilds motor starters and alternators.AARCO Radiators rebuilds automobile radiators. The potential contaminants at these two locations areradiator fluid, solvents and possibly dissolved trace metals with the solvents.

Photographic Specialties fa a photographic processing shop north of the site on Washington Avenue.Potential contaminants from this property would be associated with photographic development andcleaning fluids.

The E-Z Stop gasoline station adjoining the site to the north fa known to have underground storagetanks handling gasoline and diesel fuel Potential contaminants emanating from this property are primarilypetroleum products, and possibly solvents.

Sawyer Lumber fa located on 14th Avenue south of the site. The Sawyer property fa a retail lumberyard on which lumber products are stored. Potential contaminants at this location are wood treating

Several warehouse properties and vacant lots are also located within two blocks of the Union Scrap site.No known environmental risk fa currently associated with these properties.

Al Surface Water Hydrology

Due to the small size, location, generally levd nature of the site, and the backfilling associated with the

EPA removal action, a surface water investigatiom and evaluation was not included as part of the scopeof work in the RI Work Plan. However, as discussed in Section 2.12, Surface Water Investigation.

Remedial Invocation ReportUnion Scrip Iron and Meul Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 3

ponding of water does occur over certain areas of the site after significant rainfall events. Surface waterrunoff from the site in its current condition Is t"faim«1 Any runoff which does leave the site would flow

west along 16th Avenue on the south side of the site and then north along Washington Avenue to the

storm sewer entrance at the corner of Washington and 17th Avenues. The combined sewer system is

routed to the Pip Eye Sewage Treatment Facility located south of SL Paul During periods of extreme

precipitation, sewer system flow is bypassed to the Mississippi River. Some minor runoff from the site

may occur on the northeast corner paralleling the Soo Line railroad tracks; however, except for extreme

precipitation events, precipitation which falls on the site either infiltrates into the soil or evaporates.

The major surface water feature in the vicinity of the site is the Mississippi River located approximately

1,200 feet to the east (Figure 1-2). The river flows to the south. Pool elevation in this area is controlled

by the SL Anthony Lock and Dam #1 located approximately 7,900 feet to the south-southeast River

stage elevations from the upper pool at the SL Anthony Lock and Dam #1 and the Northern StatesPower (NSP) Company Riverside Plant located approximately 8,000 feet north of the site were obtained

from the U.S. Army Corps of Engineers for use in this investigation. The Union Scrap site is located

approximately half way between the two measurement points. Therefore, for the purposes of this report,

the Mississippi River pool elevation directly east of the site is assumed to be the mid value between the

two points.

Table 3-1 presents river stage elevations for ate dates which correspond to the dates ground water

elevation measurements were recorded. This information is discussed relative to ground water elevations

in Section 3.4, Hydrogeology.m

*

3J Geologr

3.3.1 Regional Geology

The regional geology in the metropolitan area was influenced by two main factors: the regional structural

effects of the Hollandale Embayment and Twin Cities Basin and the effects of recent glacial activity.

The late Cambrian Hollandale Embayment is a regional trough-shaped geologic structure that trends from

southwest to northeast beneath the southeastern comer of Minnesota. The Twin Cities Basin, centered

200593 WEST EAST •B1

900 —

850 —

800 —

750 —

700

650 —

eoo —

663

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633

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— 900

— 850

— 800

— 750

— 700

— eso

— 600

P

FIGURE 3-11CROSS SECTION B - B'


PROJECT NO.

11-89-185out

9/5/89

MtPAMEO fT

BDO/PR

mm^.0«Ha

Inc.

Remedial Invettintjon ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinneaouiDelta No. 11-89-185Page 8

du Chien Croup and Jordan Sandstone, the Irontoo and Galesville Sandstones, and the Mount Simon andHinkley Sandstones (Norvitch, eLal, 1973). As of 1982, approximately 80 percent of all ground water

withdrawals in the metropolitan area were taken from the Prairie du Chien-Jordan Aquifer with the next

largest amount being from the Mount Simon • Hinkley Sandstones at 10 percent (Horn, 1983)

The major river systems in the region are the ultimate discharge areas for almost all of the aquifer

systems. This is primarily due td the incised bedrock valleys that have been filled with coarse grained

alluvial sediments. These valleys provide hydraulic connections between the deeper confined aquifers and

the surficial water table. In the region of north Minneapolis, the Mississippi River is the primary

discharge area for the glacial drift aquifer as well as several of the bedrock aquifer systems.

Site Hydrogeotocr

In Section 332 • Site Geology, four major geologic units were defined during the RI Geld activities.

These were the surficial sand and gravel, the clay layer, the deeper sand and gravel, and the Shakopee

Formation, which is the upper formation of the Prairie do Chien Group. Each of these units is significant

in the evaluation of the hydrogeologfc setting at the site.

The site hydrogeology was investigated by the insinuation of seven ground water monitoring wells. Thelocations of the seven monitoring wells is presented in Figure 3-11 Six of the wells are water table

monitoring wells completed within the surficial sand and gravel unit The seventh well is a deeper aquifer

monitoring well completed approximately 10 feet beneath the clay layer. Monitoring welb MW-14s and

MW-14d are nested together and are completed in the different aquifers. The V designates the surficial

sand and gravel unit while *d* designates the deeper sand and gravel unit The following discussions of

the site hydrogeology incorporate information obtained from the monitoring wells which included ground

water elevation measurements, hydrogeologic field tests, and physical testing of soil samples. Monitoring

well construction forms and Minnesota Department of Health well records for the seven monitoring wells

are located in Appendix J.

MV-14D

MV-14?

4, 4, 4,

4, 4, 4,

4, 4, 4>

4, GRASSYAREA

LEGENDFENCE

ot

a

z

-I—I 1- RAILROAD TRACK

O LIGHT PDLE

* UTILITY PDLE

• MONITORING WELL LOCATION

SIGN

HYDRANT

-I-


PARKING LOT

MV-10

MV-7

MW-3

16TH AVENUE

MV-15MW-13

NORTH

FIGURE 3-12MONITORING WELL LOCATION MAP


fHOJGCT NO.

11-89-185DATE

8/38/89

MVM/PRRcvieweo BY Delta

Consultant*. Inc.

Remedial Invqdntion ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapofe, KfinoeaottDelta No. 1149-185Fife 9

Surfldai Sand and Gravel Aonlfer

The fint ground water beneath the site was evaluated by the completion of six water table monitoring

wells as described in Section 2.1.5.1 • Water Table Monitoring Wells. Figure 3-12 presents the locations

of six of the wells, MW-3, MW-7, MW-10, MW-13 MW-14s, and MW-15. Table 3-2 presents a summary

of monitoring well elevation data for all seven welb. This table includes the ground elevation, top of riser

(TOR) elevation, top of screen elevation, and bottom of screen elevation.

The surficial sand and gravel unit was defined to be between 43 feet and 51 feet thick with the greatest

thickness being to the east side of the site near MW-7. The thicker area corresponds with the east-

northeast downward slope of the top surface of the day layer. The water table was observed between

approximately 30 and 31 feet below the surface within the sand and gravel The saturated thickness of

the surficial sand and gravel unit varies from lest than 12 feet at MW-14s to greater than 21 feet at MW-

7. This variation is due to the slope of the clay unit surface and the generally flat water table surface

across the site. Table 3-3 presents six ground water elevation measurements taken over a 13 day period.

As shown in Table 3-3, very little fluctuation of the water table elevation was observed over this short

monitoring period. There was a significant change in the potentiometic ground water elevation in MW-

14d. It is not known if this was due to the well stabilizing or other influences, such as pumping of other

wells in the vicinity.

The water table elevations from August 11, 1989 for the six water table wells was contoured and is

presented in Figure 3-13. The remaining water table measurements exhibit a similar flow pattern when

contoured, and, therefore, are not presented. The water table elevation contour map shows a general flow

direction to the soatheast The flow direction to the southeast rather than directly to the east suggests

that there may be some influence created by the St. Anthony Lock and Dam #1. The controlled pool

level of the river had only a 0.09 foot average elevation drop (Table 3-1) from the NSP Riverside Plant

to the Lock and Dam #1, during the 13 day monitoring period. This is a distance of over 3 miles. The

river is the discharge area for the surficial sand and gravel unit The average horizontal hydraulic gradient

of the water table across the site for the period of measurement b 0.0005 feet per foot This very flat

hydraulic gradient is common for coarse alluvial sediments such as the sand and gravel observed at the

site.

TABLES-!

Monitoring WtB Elevation SummaryUnion Scrap Ira and Metal Company


Well

MW-3

MW-7

MW-10

MW-13

MW-14s

MW-14d

MW-15

GroundElevation

829.61

829.75

83038

83085

830.76

830.51

829.97

Top of RiserEkvatton

831.41

831.59

83161

83187

83182

83154

831.93

Top of ScreenElevation

804.6

803.9

804.9

803.6

803.4

738.1

805.4

Bottom of SaElevation

789.6

788.9

789.9

788.6

788.4

733.1

790.4

All elevations in feet NGVD.

klw.830

TABLE 3.3

Ground Water Elevation MeasurementsUnion Scrap Iron aad Metal Company

Delta No. ll-W-l&S

WeB

MW-3

MW-7

MW-10

MW-13

MW-14S

MW-14d

MW-15

9/409

799.42

799.43

799.46

799.40

799.49

789.97

79937

S/7/89

799.45

799.48

799.47

799.37

799.50

79131

79936

S/1M»

799.42

799.44

799.47

79937

799.45

79LS9

79935

1/1LK9

79938

79938

79938

79934

799.45

791.42

79930

8/15/8*

799.41

799.41

799.51

79939

799.46

791.42

79937

8/17/89

79924

79925

79928

79920

79930

791.48

799.17

|Mfl if • ittilili

Change

021

023

023

020

020

234

020

Average

79939

799.40

799.43

79935

799.44

79132

79932

All elevations in feet NGVD.

khv.830

E - 2 STOPCONVENIENCE STORE

PARKING LOT

ff—• • • • •(799.34) /9 MV-13 |

LEGENDFENCE

-J—I—I- RAILROAD TRACK

O LIGHT POLE

* UTILITY POLE

(799.34) WATER TABLE ELEVATION <IN FEET)

—— WATER TABLE CONTOUR

NORTH

40

S01£ M FEET

FIGURE 3-13WATER TABLE CDNTDUR MAP

AUGUST 11, 1989UNION SCRAP

MINNEAPOLIS, MINNESOTAPNQJECT NO.

11-89-185DATE

8/32/89

PREPARED BY

MVM/PRREVIEWED BY Delta

EnvtnnmMiM

Remedial Invocation ReportUofca Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149-185Page 10

Single well recovery rate tests were conducted on an of the monitoring wells at the site as described in

Section 2.1.5.6 Hydrogeologic Field Tests. The data collected during the test was analyzed using a

computer program (Thompson, 1987) to estimate the hydraulic conductivities of the sediment adjacent to

each well screen. Water levels were recorded as the slug was suddenly introduced into the well and as

it was quickly extracted. In addition, particle size distribution tests were completed for sediment samples

collected from the screened interval at each water table well location.

The hydraulic conductivity was estimated by the Hazea Approximation (Freeze and Cherry, 1979) which

uses the effective grain size (as determined from the particle size distribution tests):

K - A d192 (Equation 3-1)

Where: K - Hydraulic Conductivity (centimeters per second (cmAec))A » 1.0 if the units of en/tec and millimeters (mm) are useddu « effective grainsize (nun) (grainsize diameter at which 10% by weight are finer)

The equation was used to calculate hydraulic conductivities (COI/MC) which were then converted to feet

per day.

Table 3-4 presents a summary of the hydraulic conductivity estimates for the slug in, slug out, and Hazen

Approximations and an average value for each well The averaged values for the surficial sand hydraulic

conductivity range from 110 feet/day to 285 feet/day. These values fall within expected estimates of

hydraulic conductivities for sands and gravels (Freeze and Cherry, 1979 and Driscoll, 1986> The slug test

computer analysis printout, plot of the drawdown data and regression curve, and the raw field test data

are included in Appendix M. Particle size distribution curves are found in Appendix K.

The primary component of flow within the coarse alluvial sediments a assumed to be horizontal, especially

if there is a defined less permeable base to the formation. This is the setting at the Union Scrap site.

The surficial sand unit is bounded at the base by the less permeable clay unit Therefore, the primary

component of flow of the water table may be considered horizontal The horizontal flow velocity may

then be calculated using Darcy's Law:

TABLE 3-4

weaSnrfldalSand

MW-3

MW-7

MW-10

MW-13

MW-14*

MW-15

ShMlB

140

140

110

140

NA

140

v*

O23

023

O18

023

NA

023

v*

O20

020

016

020

NA

0.20

kr**MBO^B^M w w mmw^mm • •••••

Union Scrap Iron iMlnneapoll

Delta No

Slut Pot VM VM

85

NA

85

85

110

110

014

NA

O14

014

O18

0.18

O12

NA

0.12

012

0.16

0.16

and Metal Companys, Minnesota. 11-49.185

Hasena mmmmm**mt^»tt ~ ** * *ADpronnuilf

550

550

280

280

110

85

S9 M

O92

O92

O47

047

0.18

014

O79

O79

O40

O40

O16

014

WenAverage

255

285

170

170

110

110

Average

038

O48

O28

0.28

0.18

0.18

032

O41

O24

024

0.16

0.16

Deep Sand

MW-14d 55 NA

Data presented as feel/dayNA • data not availableVM • Horizontal flow velocity calculated using porosity of 30%Vj5 - Horizontal flow velocity calculated using porosity of 35%

klw.830

NA

Range: lit-285 H48-O.U

Remedial Invtttintton ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149-185Page 11

V - Ki (Equation 3-2)D

Where: V - Average Horizontal Flow Velocity (feet per day)K - Hydraulic Conductivity (feet per day)i - Horizontal hydraulic gradient (feet per foot)n • Porosity (unities*)

Using the range of averaged well hydraulic conductivity estimates presented in Table 3-4, the average

hydraulic gradient of 0.0005 feet per foot, and a range of porosity for medium to coarse sands of 30 to

35 percent (Freeze and Cherry, 1979 and DriscoU, 1986) the horizontal flow velocity varies from 0.16

feet/day to 0.48 feel/day.

As stated previously, ground water is present beneath the site at approximately 30 to 31 feet The vadose

zone is then considered the unsaturated portion of the surfirial sand above the water table and capillary

fringe. This zone is also an important part of the hydrogeologk evaluation of the site because the

migration of any contaminant to the water table would occur by infiltration through this zone, either as

a separate phase or carried by the infiltrating water. Four representative undisturbed vadose zone soil

samples were collected using a lined split spoon from the shallow on site borings B-l, B-8, B-ll, and B-

12. These samples were tested to determine the moisture content and saturated vertical permeability of

the soil from approximately midway between the surface and the water table. Table 3-5 presents the

results of the constant head vertical permeability tests. Three identical tests were completed on each

sample and the avenge of the three is the value presented. The sample interval, soil moisture content,

average vertical permeability, and soil density are tilted. The vertical permeabilities of the vadose zone

soils (saturated) ranged from 23 feet/day to 57 fcetAIay. The soil density ranged from 983 pounds/cubic

foot to 1033 pounds/cubic foot The grain size distribution curves, located in Appendix K, showed that

all four samples consisted of greater than 91 percent sand sized particles with very little clay or silt

3.4.11 Clav Lover

The occurrence of the clay layer fa hydrogeologicalry important not as an aquifer system but as an aquitardbetween the surficial sand and gravel water table and the deeper sand and gravel unit below the clay.

TABLE 3-5

Summary of Moisture Content, Vertical Permeabilities, andDensity of the Snrfidal Sand Unit

Union Scrap Iron and Metal CompanyMinneapolis, Minnesota

Delta No. 1149-185

SampleLocation

B-l

B-8

B-ll

B-12

SampleInterval

13 - 15 feet

13 • 15 feet

13 - 15 feet

15 • 17 feet

MoistureContent

5.5%

3.7%

5J6%

1O2%

AverageVertical Permeability

26

57

57

23

Density(KT\

98.9

1017

103J

983

Permeability presented in feel/day

PCF • pounds per cubic foot

khv.830

Remedial Investigation ReportUnion Scrap Iron cod Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 12

The clay layer was defined at borings B-14A and B-14B to be present from 43 feet to 84 feet below thesurface. It was also observed across the site showing a slope of five percent to the east-northeast. The

clay appears to act as an aquitard between the surffdal sand and gravel and the deeper gravel

A lined spoon sample of the clay was collected at B-14A from 55 to 57 feet below the surface, 12 feet

to 14 feet into the clay layer. This sample was tested for particle size distribution, moisture content,

vertical permeability and density. Table 3-6 presents the results the moisture content, vertical permeability

and density analyses. The particle size distribution was plotted on a curve that is located in Appendix LThe vertical permeability of the clay or glacial till is 6 x 10*5 feet/day.

3.4.} 3 Deep Sand and Gravel and Prairie du Chlcn • Jordan Aquifers

The primary hydrogeologic objective of the RI field investigation was to define and characterize the

snrficial sand and gravel water table aquifer because it is the first aquifer system that would be impacted

by site derived contamination. The second hydrogeologic objective was to determine if a confining layer

was present and to identify the next significant water bearing unit beneath the confining layer.

The clay unit as described in Section 3.4.Z2, day Layer was defined as being an impermeable unit incomparison to the surficial sand and gravel The next significant water bearing unit was identified to be

a sand and gravel unit from 84 feet beneath the site to the top of the bedrock at 192 feet below the

surface. This unit has a total thickness of 108 feet No secondary confining layers were identified within

the sand and gravel between the day and the bedrock.

Monitoring wed MW-14d was completed to a depth of 98 feet below the surface and is screened from 93

to 98 feet Potentiometric head elevations collected from MW-144 are presented in Table 3-3.

Monitoring well MW-14*, which is nested with MW-144, has had consbtanUy higher water elevation than

MW-14A Using the averaged ground water elevations of 799.44 for MW-14s and 79132 for MW-14d, a

total of 8.08 feet of elevation difference exists between the two wells, displaying a significant downward

gradient This lower elevation in MW-14d may be due to the hydraulic connection of the deeper sand

and gravel unit to the bedrock aquifer, the Prairie do Chien • Jordan Aquifer.

TABLED

Summary of Moisture Content, Vertical Permeability andDensity of the Clay Layer


Delta No. 1149-185

Sample Sample Moisture VerticalInterval Content Permeability Density fPFQ

B-14B 55- 57 feet 47% 6x10^ 96.6

Permeability presented in feet/day

PCF » pounds per cubic foot

klw.830

Remedial Invenlattoo ReportUnion Scrap Iron and Metal Compuy1606 WMtaio|toa Avenue NorthMinoeapolif, MinneiouDelta No. 1149-185Page 13

A recovery rate test was performed on MW-14d and evaluated using the same method as the six water

table wells. An estimate of the horizontal hydraulic conductivity for the deeper sand and gravel at the

screened interval b 55 feet/day. Because there is only one monitoring well completed into the deeper sand

and gravel unit, the flow direction, hydraulk gradient, and velocity cannot be calculated. However, if the

sand and gravel unit is in direct hydraulic commuaicaUoD with the Prairie dn Chkn - Jordan aquifer, it

can be assumed that the discharge areas would be similar. The discharge area for the Prairie du Chien -

Jordan in this area is the Mississippi River. Figure 3-14 presents a hydrogeologic map of the Prairie du

Chien • Jordan Aquifer in the east central area of Hennepin County, Minnesota. Figure 3-14 shows the

regional flow direction in the Prairie du Chien • Jordan Aquifer to the east in the area of the site. The

potenUometric head measured in MW-14d compares closely to that presented on the map. Abo shown

on Figure 3-14 b a hatched area to show a aone of significant seasonal drawdown within the downtown

area of Minneapolis. This drawdown b due to increased pumpage of many high capacity welb during

summer months. A 234 feet rise in the poteatkMnetric elevation of MW-14d was observed between

August 4 and 7. This may be the result of variable pumping of the high capacity welb. The flow regime

within the Prairie du Chien would be altered depending upon the area, location, and amount of drawdown.

3^ Demography araj* |<*nfl VfT

3A1 Land Use

The area surrounding the Union Scrap site b vied primarily for commercial/ industrial purposes (Figure

2-2). With the exception of Washington Avenue, traffic into and out of thb area b related primarily to

the local businesses and industries. Washington Avenue b a busy four-lane street that borders the site

to4he west and carries traffic to and from Minneapolis. Just beyond the avenue b a grassy border and

a fence restricting access to the freeway, Interstate 94. The freeway b a major commuter route for

Minneapolis. An off-ramp from the north-bound freeway lanes directs traffic onto Washington Avenue

at 17th Avenue, one-half block north of the site.

Immediately north of the site b an E Z Stop gasoline station and convenience store. The E Z Stop b

heavily used primarily by the local working population, and b busiest in the morning, at lunch, and after

work. To the north of the E Z Stop b 17th Avenue, and a business called Photographic Specialties.

II

• UJ.

-- 900

In fed tbovt K* levd:

Good direction of p<

W«er«dl

mt JO tea

c«wi30fca)

[ POOD 1000-2000 L>a»p,FOKMW yiddi In frikn per

tOCATBMIMfiHM

WT: KXXTTSKT. R.. I9M

FIGURE 3-MPRAIRIE DU CHIEN-JOROAM AQUIFER MAP


11-M-I65MES-24-M

JMK/ISmoD*BDO MM^

Delta

Remedial Invention ReportUnfcm Scrap Iron and Meul Company1606 Washio|too Avenue NorthMiooMpolif, MinnetouDelta No. n-»-\8SPage 14

Photographic Specialties is a high-end company that caters more to professional photographers and

corporations than to the general public. Traffic into and out of this location b not great East of

Photographic Specialties and northeast of the Union Scrap site are the Kirshbaum-Knipp Metals Co. and

an Auto-Truck Parts Warehouse. Both operations are enclosed in buildings.

The Union Scrap site is bordered to the east by a Soo Line railroad spur, and beyond the spur, by Martin

Bush Iron and Metal Company. The company's property coven an area approximately twice the size of

the Union Scrap site, extending beyond the site boundary to the northeast One or two crane operators

work along the western border of the property each day. The Martin Bush property is bordered to theeast by 2nd Street, and beyond 2nd Street by an even larger scrap recycler, Sam Bloom Iron and Metal

This company's property extends south between 2nd Street to the west and railroad tracks to the east, to

beyond 15th Avenue.

Another recycling company, SCRAPCO, is located on the northwest corner of the 2nd Street and 15th

Avenue intersection. South of 15th Avenue are more vacant lots and businesses including a plumbing and

pump supply store and a lumber yard.

Demography

There are three categories of human population associated with the area around the Union Scrap site.

Pint, the workers and customers associated with the local businesses constitute an adult, daytime

population. Second, a larger number of adult workers pass through the are* commuting to and from more

distant Jobs, and using the E Z Stop. Finally, an unknown number of transients frequent the area both

day' and night Although no residential property if officially located in this area, some transients are

believed to live in various shelters near the Union Scrap site. The size and characteristics of these three

populations has not been further defined.

4.0 NATURE AND EXTENT OF CONTAMINATION

4.1 Introduction

Union Scrap site soils and ground water were characterized for possible contamination by collecting and

analyzing 36 soil samples and 14 ground water samples.

The thirty six (36) soil samples were collected from twelve on-site sofl borings (Figure 2-8) at threespecified depths within each boring (Figure 2-9). Table 4-1 MunmariMa the intervals from which soil

samples were collected. Twenty six (26) soil samples were analyzed for potychlorinated biphenyls (PCBs)

and a minimum of seven metals; arsenic, "frtmi*"''. chromium, copper, lead, mercury, and nickel

Polycblorinated biphenyls and the seven metals comprise the short list target compounds (Table 2-4).

Ten (10) soil samples had additional analyses performed to identify volatile*, and semivolatiles, Le., the

complete Target Compound List (TCL) for organic compounds (Table 2-2), and 17 additional inorganicanalytes, the Target Anatyte List (TAL) for inorganic analytes (Table 2-3). Table 4-2 lists all thirty six

soil samples and duplicates upon which the various analyses were performed.

Ground water samples were obtained from seven monitoring wells located on and off site (Figure 2-13).

During August, two rounds of ground water samples were collected from each well The initial round of

samples was collected on August 7,1989 and the second round was collected on August 10. 1989. All

of these ground water samples were analyzed for the TCL and TAL compounds.

Additional ground water samples were obtained from monitoring wells MW-7, MW-10, and MW-15 on

September 19,1989. These samples were collected to verify the presence (or absence) of PCBs in groundwater. Consequently, these samples were only analyzed for PCBs. Four ground water samples were

collected from each monitoring well One sample was collected using a bailer and analyzed for PCBs

similar to the previous two rounds of samples. The subsequent three samples were collected utilizing a

teflon bladder pump. These samples were coOected by pumping the water directly into the sample

container to eliminate the possibility of surface dost contaminated with PCB from entering the bottle.

These pumped ground water samples were analyzed for a modified PCB analysis to obtain a method

detection limit of 0.05 micrograms per liter.

Appendix N contains sampling information for the soil and ground water samples collected. Appendix

O contains the analytical data for these samples.

800a i2i

a^

a^

0 0 0 0a st*» o

0 0 0 0s a

00fl

00a

00s

a s s^•4 ^* ***

2o

aAs

fiflfiooaafi? 3 5 j y - . r o o < N

$ & & &

iD D 3

1 a f l f l f l a a a a a f i a a§ § §

ii |

§s s s s s a s s s a s s

ce!1 is

iif! Ill2

s e si i

i:1 3 S S S

S *M »M. = aS s? s?W CO CrtD D D

§ a ia s s f l a a a a a a a a

S s a 5 B s sS

3 a a s 2 2 2 2 2 2 2

s s

*%* nr il i t 3 S

e e

^ « i

D 3 S

TABLE 4-2

Soil Sample AnalysesUnloo Scrap Inn and Metal Company


Soil Sample

Boring

B-l

B-2

B-3

Parameters Analyzed

B-4

B-5

B-6

B-7

B-9

Intermi Volatile! Semhoiatn

shallowintenneddeep

shallow x zintenneddeep x x

shallow x xshallow (D) xintenned•denned P)*** xdeep x x

shallow ••• x xintenneddeep

shallow x xintennedintenned (D)deep x x

shallow x xintenneddeep

shallow x xintenneddeep x x

shallowintenneddeep

shallowintenneddeep

fi PCBi 14 Anahrtes(TAL)'

xxX

X X

X

X X

X X

X

X X

X X

X X

X

X

X X

X

X

X X

X X

X

X

X X

X

X X

X

X

X •

X

X

X

TAnaMes(short Bst) ••xX

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X


Soil Sample

Boring

B-10

B-ll

B-12

shallowshallow (D)interneddeepdeep(D)

shallowin termeddeep

shallowin termeddeep

Parameters Anlayzed

Volatile* PCBs 24 Analvtes(TAL)

7 Anatvtes(short list)

zX

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

D - indicates duplicate sample taken* TAL - Target Anahyte List (Table 2-3)•• Short List « Short list of parameters (Table 2-4)*•• Analyses represented is consistent with analytical results, field sheets may differ.

khv.920

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDeha No. 1149-185Page 2

4.2 Characterization of Contamination In Sofl

4.2.1 Volatile Contamination

Ten toil samples were each analyzed for thirty torn volatile organic compounds. These ten samples

include six shallow samples and four deep samples. As shown in Table 4-3, volatile organic compounds

(VOCs) were found in only two of the ten samples, B-5 (deep) and B-7 (shallow). Only one VOC wasfound in each sample: tetrachloroethene was found at a concentration of 6 micrograms per kilogram

(ug/kg) in B-5 (deep) and trichloroethene was found at 11 ug/kg in sample B-7 (shallow). These

concentrations correspond to 6 and 11 parts per billion, respectively. Boring B-5 is located in the

northwest quadrant of the site and boring B-7 it near the middle of the eastern boundary of the site(Figure 2-8). (Note: The laboratory reports in Appendix O identify these compounds as

tetrachloroethylene and trichloroethylene. The root word ethylene and ethene are synonyms and identify

the same chemical structure. This report utilizes ethene for the double bond carbon organic compounds).

As described in Chapter 3, all soil samples were scanned with an hNu photoionization detector

immediately upon sample retrieval from the boring. The hNu scans of soil samples collected from depths

greater than those which were anlayzed in the laboratory did not show any volatile organic content: It

should be noted however, that the detection limit for the hNu detector is approximately one pan per

million or roughly a thousand times greater than the laboratory detection limit for these compounds. The

hNu data are presented on the boring logs in Appendix L

4*2.2 Semivototite ContanUnattoB

Ten soil samples were each analyzed for sixty five semivolatile organic compounds. The ten soil samples

include six shallow samples and four deep samples (Figure 2-9).

No semivolatile organic compounds were detected in the soil samples.

4.2.? Porvchlorinated BlPhenvl Q>n**'i>tnatton

Thirty six sofl samples were -analyzed for seven PCS compounds. The results of these analyses are

presented in Table 4-4.

TABLE 4-3

Volatile Orfank Contamination in SoilUnion Scrap Iron and Metal Company


Soil Sample Comnonnd Concentration fog/ki)

B-S deep tetiadiloroethene 6

B-7 shallow trichloroethenc 11

klw.829

PCB Cootaatfnattoo lo SoilsUnion Scrap Iron and Metal Company

Minneapolis, MinnesotaDelta No. 1149.185

Soil Sample PCB Detected Concentration

B-4 ihallow Arocator-1248 120

B-S ihallow Arochlor-1248 220

B-S deep AncUor-1248 1000

B-10 shallow Arochlor-1248 94

B-10 shallow (duplicate) Arochlor-1248 200

khv.920

Remedial Invettintlon ReportUokxi Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MfoneaotaDelta No. 11-89-185Page3

Ooe commercial PCB mixture, Arochlor - 1248, was detected in four soil samples. This includes three

shallow soil samples and one deep sample. The three shallow samples were from borings B-4 located in

the west central side of the site, B-8 located in the south central portion of the site, and B-10 located in

the east central portion of the site. In B-4, the concentration was 120 ug/kg in B-8, 220 ug/kg, and in B-

10, 94 ug/kg. A duplicate analysis from B-10 showed 200 ug/kg. A single deep sample, B-8, contained

1,000 ug/kg. These concentrations are equivalent to parts per billion (ppb). Thus, the highest sofl

concentration is 1,000 ppb or one (1) pan per million.

4.2.4 Inorganic Contamination

Inorganic analyses of soil samples included cyanide and twenty three metals. Ten soil samples were each

analyzed for the TAL analytes (Table 4-2). The remaining 26 soil samples were analyzed for a shorter

list of metals including arsenic, cadmium, chromium, copper, lead, mercury, and nickel

Table 4-5 summarizes the analytical results of inorganics in soil The table is arranged by analytes, sample

location in each borehole (shallow, intermediate, and deep), number of samples collected, number of

samples with a detectable concentration of the anatyte, the reported concentrations, and the average of

reported concentrations.

4A4.1 OanMc

Cyanide was not detected at or above the detection limit of 500 ug/kg in any of the eleven soil samples.

4A4J Lead

All thirty six soQ samples were analyzed for lead. Figure 4-1 and Table 4-5 summarize the lead results.

Reponed lead concentrations range from 4.9 to 102 milligrams per kilogram (mg/kg) with an average lead

concentration from all samples collected of 15.4 mg/kg. The highest lead concentration, 102 mg/kg, was

found in the shallow soil sample from boring B-d. Boring B-6 is located in the middle of the south side

of the site.

4.2.4.3 Remainlnt TAL Mftalf

This section discusses the analyses of the remaining metals not discussed in Section 42.4.2. Several metals

on this list are common soil constituents. These metals are aluminum, calcium, iron, magnesium,

Anatrte

Aluminum

Antimony

Arsenic

Barium

Beryllium

Cadmium

Calcium

Chromium

Cobalt

Copper

Location

shallowdeep

shallowdeep

shallowintermeddeep

shallowdeep

shallowdeep

shallowintermeddeep

shallowdeep

shallowintermeddeep

shallowdeep

shallowintermeddeep

TABLE 4-5

Summary of Inorfank Results In SoilsUnion Scrap Iron and Metal Company


ConcentrationRanee

NumberofSamples

64

64

121212

64

64

121212

64

121212

64

121212

Nnfifj

64

00

10164

52

111

64

121211

64

111110

Average

1960 • 53101230 - 1610

NDND

1.4ND1.4

17.0 • 14813.5 - 18.0

<0.29 - 0.79

30881378

62.615.4

0.69

1.50.981.4

665- 147006350-26400

42 • 10.725 • 10.2<1.9 - 5.6

4.6 -8J5.6 - 7.7

13-92<0.69 - 162<0.69 - 19.6

331719313

6.7523.8

6.7

335.662

Table 4-5Continued

Analvte

Iron

Lead

Magnesium

Manganese

Mercury

Nickel

Potassium

Selenium

Silver

Sodium

Thallium

Vanadium

*

Zinc

Cyanide

Location

shallowdeep

shallowintermeddeep

shallowdeep

shallowdeep

shallowintermeddeep

shallowintermeddeep

shallowdeep

shallowdeep

shallowdeep

shallowdeep

shallowdeep

shallowdeep

shallowdeep

shallowdeep

NumberofSamples

64

121212

64

64

121212

121212

64

64

64

64

64

64

64

64

Number ofDetectConcentrations

64

121212

64

64

001

121212

10

00

00

00

00

64

64

00

ConcentrationRanee (me/kg)

4180-138004080-4750

4.9 - 1025.7 - 7336.6 - 13.9

934-44802220-6630

207-1290304-543

NDND0.03

8.0 - 17.54.4-21213 • 17.6

417ND

ND(R)ND(R)

NDND

NDND

ND(R)ND(R)

6.0-12.653 -6.4

10.6 - 58.610.8 - 593

NDND

ArerageConcentration (me/kg)

71654383

19.417.19.8

16865160

611427

_•

13.011.4115

. .»

. .

• •

• •

» •

- -

• -

&55.5

27.223.8

• -

*- - Average not applicableND - Not detected at or above the method detection limit(R) - Data is unusable

n E - z STOP

Ir-

aZ

LJZ)2LJ

. ><

2

ai-13

52

| SIGN CONVENIENCE STORE1 PAPKTNH LOT

B~10

s-r»~D |_

1 15 2^ °~- D- 8.6

o9.36.87.0

B-llS- 8.3 O1- 8.8 -ID- 8.6

J0 B-9

i

Ûaco

©

LEGEND V• • r~rupr"• • r C.NUC.

S- 13.2 J

B-40 [

S- 5.4 B-3!•• 5 7 f*\D- 91 S- 4.9 U

I- 10.1D- 9.4 B-8

- 11.0

/">?n -TB-7 o

U S- 28.8I- 6.40- 13.2

O S- 25.5I- 73.3

B-2 °" 9'1 B 6B-l /-\ <;— s fi DO0 O S- 8.8 Op 5-° o S- 1021- 33.1 L ini

+ * D- 12.61- 6.7D- 13.9

B-12

S- 7.3- 7.2D- 9.7 "

0

—

--

V. \\\\\. \v \-\ j^-

\~T

\nT\

HYDRANT 16TH AVENUEI l l nAYI DnAn TOA/*IX

O LIGHT POLE

« UTILITY POLE .

O SOIL BORING LOCATION 1

I- 6.2 SAMPLE LOCATION LEAD CONCENTRATION |TOTAL LEAD ng/kg NORTH

0 30S SHALLOW I- INTERMEDIATE D- DEEP tiSaf?!!3

SCALE M FEET

FIGURE 4-1LEAD CONCENTRATION PROFILES


PROJECT NO.

11-89-185DATE

10/12/89

PREPARED B

MVM/PF

REVIEWED ff-AkDeltaCiulruuiLuJiilCancuNanta. loe.


potassium, and sodium. Trace metab on the anatyte list are antimony, arsenic, barium, beryllium,

cadmium, chromium, cobalt, copper, manganese, mercury, nickel, selenium, silver, thallium, vanadium, and

zinc

Except for potassium and sodium, the six common metals were detected in all sofl samples. Potassium

was found in only one shallow sample and sodium was not found in any samples above the method

detection limit Table 4-5 summarizes the analytical results of these samples.

For comparison, Table 4-6 lists concentrations for aluminum and magnesium found in natural soils.Aluminum concentrations for all sofl samples are below the average natural soil concentration. The

average soil concentration for magnesium is slightly higher at the Union Scrap site than the natural

concentration (5160 mg/kg vs 5000 mg/kg). Aluminum concentrations exhibit a decrease with depth.

However, magnesium concentrations exhibit an increase with depth. Iron concentrations also show a

decreasing trend with depth, which would be expected for the soils at a netal scrapping facility. Calcium,

on the other hand exhibits an increasing trend with depth.

Two trace metals were not detected at or above the anatyte method detection limits. These metals and

method detection limits are antimony (10 mg/kg), and silver (10 mg/kg).

Twelve trace metals were detected in site sofls. All of these metab except cadmium were found at

concentrations within the concentration range farad in natural soils (Table 4-6). These trace metals are

arsenic, barium, beryllium, chromium, cobalt, copper, manganese, mercury, nickel, vanadium, and zinc.

The cadmium detection limit ranged from 0.49 Co L9 milligrams per kilogram which is slightly above the

highest concentrations reported for natural soib. However, of thirty six samples run for cadmium, only

three showed levels slightly above the detection limit Consequently, cadmium levels at this site appear

to be close to concentrations reported for natural soib.

The remaining two trace metal analyses, selenium and thallium, produced unusable results. The laboratory

had to label these results as unusuable because four selenium spike analyses and one thallium spike

analysis showed 0% recovery in the solid matrix.

TABLE 4-*

Metal

AluminumAntimonyArsenicBarium

BerylliumCadmiumChromiumCobalt

CopperLeadMagnesiumManganese

MercuryNickelSeleniumSilver

VanadiumZinc

Trace Metal Cooceotratloiu In Natnral SoilsUnion Metal Iron and Scrap Company

Minneapolis, MinnesotaDelta No. 11»49-185

Common Range

10,000 • 300,0002-101-50100 - 3,000

0.1 -400.01 - 0.71 - 1,0001 -40

2- 1002-200600-6,00020-3,000

0.01 - 035-5000.1 -20.01 - 5

20-50010-300

Average

71,000

5430

60.061008

30105,000600

.0340030.05

10050

Source: US EPA Office of Solid Watte and Emergency Response, HAZARDOUS WASTE LANDTREATMENT, SW-S74 (April 1983) Page 273, Table 6.46.

klw.905


Sun

All thirty six soil samples were analyzed usinf the EP Tenacity leaching procedure for arsenic, cadmium,

chromium, copper, lead, mercury, and nickel These seven metals were selected for leach testings because

they are associated with lead-acid batteries. Results of the leach testing are presented on the laboratory

reports in Appendix O. All metal leachate concentrations were found to be below the contract required

detection limits, which are as follows: lead at 3 ng/1, arsenic at 10 ug/1, cadmium at 5 ug/1, chromium at

10 ug/1, copper at 25 ug/1, mercury at 0.2 ug/1, and nickel at 40 ug/L

Previous investigations report EP Toxkity leaching procedure results from soil at 7.5 feet deep of 0.59 and

5.4 milligrams per kilograms lead near the present B-9 and B-2 (Braun Environmental Laboratories, 1986).

This investigation did not find lead EP Toxkity concentrations at the higher levels found in the earlier

investigation.

4.2.5 Summary of Soils Contamination

Volatile contamination in soils was limited to two volatile organics, tetrachloroethene and trichloroethene.

These organics were found in low concentrations, 6 ug/kg and 11 ug/kg, and at different locations and

depths, B-5 (deep) and B-7 (shallow), respectively.

There does not appear to be any significant source of either of these organics on site. The

trichloroethene found in B-7 shallow was not found in deeper samples at that location. Compared to

ground water concentrations of trichloroethene (TCE) discussed in Section 43, the TCE concentration

in soil is not significant.' Tetrachloroethene was found only in the deep sample in boring B-5. Also, as

discussed later in Section 43, no tetrachloroethene was found in ground water, consequently there has

been no impact of tetrachloroethane on ground water. Based on their limited extent and magnitude, the

volatile organics do not appear to be a continuing source or significant contaminants at this site.

No semivolatile. contamination was found in she sofls.

The only PCB detected in site soils was ArochJor-1248. This PCB was found in low concentrations at only

four locations. These locations and concentrations are 120 rag/kg at B-4 (shallow), 220 ug/kg at B-S(shallow), 1,000 ug/kg at B-8 (deep), and 200 u|/k| at B-10 (shallow). This concentration range, 120ug/kg to 1,000 ug/kg, is low, particularly for sofls in the vicinity of this site (MPCA files). Deeper

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Wasbinfton Avenue NorthMinoeapoiit, MinoeaotaDelta No. 1149-185Page 6

samples collected from B-4 and B-10 did not reveal detectable levels of Arochlor-1248. In B-8 where

PCBs were found at 2 to 4 feet and 10 to 12 feet below the surface, they were absent in the intermediate

sample. Based on the limited extent and magnitude of PCBs found in subsurface soils, it appears most

of the PCB contamination originating from Union Scrap Iron and Metal Company operations was removed

during the EPA Emergency Removal Actions in 1988.

As discussed in Section 112 Surface Water Investigation, a single sample of puddled surface water was

taken from the southeast corner of the site and analyzed for PCB contamination. This sample consisted

of rainwater and surface sediments. The PCB concentration in this sample was 11 micrograms per liter

(ng/1). The PCBs in this puddle sample are probably contaminants in the surface sediments due to

previously deposited airborne contamination from other uncovered PCB sources in the area since

completion of the EPA Removal Actions eight months earlier. The source of the 'clean* surface backfill

brought in by EPA is from Mill City Excavating and Landscaping and was brought in from a clean fillsource on the north side of the Twin Cities. These soils were not tested prior to being spread across this

site, but it is unlikely they were contaminated with PCBs. Therefore, the present surface PCB

contamination is likely airborne contamination (attached to windblown dust) from PCB contaminated soils

identified in the general area. Thus any significant surface contamination remaining at this site is probably

not from Union Scrap Iron and Metal operations bat from other surface sources in the vicinity.

No cyanide contamination was found in site soils.

The lead levels detected in sofl samples at the site are within the range of lead found in natural soils in

the United States. Natural soils have been found to contain lead in concentrations from 2 to 200 parts

per million (ppm) or rag/kg (USEPA, 1983) (Table 4-6). The highest lead concentration found in site

soils was 102 mg/kg. This is well within the range of natural soil lead concentrations.

Lead was analyzed in off-site surface soOs considered to be background for the area by an EPA technical

assistance team in October 1987 (Section 13.4, History of Response Actions). Background concentrations

at the surface were 492 mg/kg and at six inches below surface, 333 mg/kg. These are relatively high but

are probably indicative of this area where auto salvaging and metal scraping operations have been

prevalent for many yean.

Remedial Investigation ReportUnion Scrap Iron aod Metal Coopuy1608 Washington Avenue NorthMinneapolis, MinnesotaDelu No. 1149-185Page?

Based on these results, it appears any lead contamination originating from Union Scrap Iron and Metal

Company operations was removed during EPA's Emergency Removal Actions in 1988.

The remaining metals analyzed in site sofls are the six common metals: aluminum, calcium, iron,

magnesium, potassium, and sodium, and the following trace metals: antimony, arsenic, barium, beryllium,cadmium, chromium, cobalt, copper, manganese, mercury, nickel, selenium, silver, thallium, vanadium, and

zinc.

The common metals are generally within the range found in natural soils (Table 4-6). However, two of

the metals, magnesium and calcium, exhibit an increase in concentration with depth. This trend could be

the result of Union Scrap operations. Water with a low pH from the lead and battery crushing process

could have infiltrated near surface soils and mobilized (leached) these cations to produce this trend.

The iron concentration decreases with depth. This trend would be expected in soils beneath metal

scrapping operations where metal cutting, processing, and storage occur outside and iron oxides would be

leached to the surface soils causing elevated iron concentrations. Thus, even though iron would be

leached downward along with other metals, surface concentrations could remain higher.

Twelve trace metals were detected in site soils (Table 4-5). All except cadmium were found at

concentrations expected in natural soils. Three sofl samples had cadmium concentrations slightly above

naturally occurring concentrations.

In summary, the common metals and the trace metals are present at concentrations similar to natural soils.

The inorganic leach testing (EP Tenacity) method is designed to mimic landfill leaching processes and is

used to determine whether a waste material b hazardous or not The test results for lead, arsenic,

cadmium, chromium, copper, mercury, and nickel, were at levels below method detection limits and below

the limits defining a waste as hazardous. This is according to definitions in the Resource Conservation

and Recovery Act (RCRA) United States Code (USC) Title 42, Code of Federal Regulations (CFR), Title

49 and Minnesota Statutes 115 and 116 as well as Minnesota rules Chapter 7045. Consequently, none of

the samples analyzed are hazardous.

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185PageS

43 CharacterlCTtion of Contamination In Ground Water

4J.1 Volatile ContamlnaUon

Two rounds of ground water samples from an the wells were analyzed for volatile*. Seven organic

compounds were detected in the shallow ground water samples. The results of these analyses are

presented in Figure 4-2 and Table 4-7.

No volatile organic compounds were detected in the deep well, MW-144. This well is to the northwest

of the site screened in the sand aquifer below the day layer. This was the only point sampled within the

deeper aquifer.

Trichloroethene was detected in each of the six shallow wells. Trichloroethene concentrations ranged from

12 ug/1 in on-site well, MW-10, to a high of 650 ng/1 in off-site well, MW-13. The highest concentrations

of trichJoroethene were found in upgradient well MW-14* and in MW-13 south of the site (Figure 4-2).

1,2-Dichloroethene was detected in all shallow wdb except MW-10 on the north central side of the site.

Concentrations for the two rounds of sampling ranged from 10 to 21 ug/L Concentrations were similar

whether upgradient or downgradient and on site or off site.

1,2 • Dichloroethane was detected in low concentrations in two monitoring wells. The highest

concentration was 13 ug/1 in MW-14s, which is npgndient and off site. It was also found in on site

MW-10 at a concentration of 11 ug/L«

1,1-Dichloroethane was found on site in MW-7 and down gradient in MW-15. The concentrations ranged

from a high of 9 ug/1 in on site well MW-7 to 5 vf/I in MW-15.

1,1,1 - Trichloroethane was detected in MW-7 and MW-15, also. Concentrations in MW-7 were slightly

higher (12 and 8 ug/1) than MW-15 (5 and 7 ag/1).

Benzene and xylenes were found only in MW-10. Benzene ranged from 92 to 110 ug/1 while xylenes

ranged from 6 to 12 ug/L

* \\+ + V

* * ^DCE 10 (12) ND

OfcA 11 (13) MW-14DTCE 260 (320) « $

MW-14S+ + +

^^ Ni ^^

* „ , * * * « , • '* .* <*

> * / " * ' > k

M, GRASSY ,4,AREA

\^ \L^ ^^

Ni' i'' ^

^^ ^L/ ^^

i rnrwn

Xi—

3u>L

aa

D E - Z STOP

9

•*.3

Xi— «vt

o

\

SIGN CONVIENIENCE STORE1 PARKING 1 HT

_MW-10* DCA 6 (11)

TCE 12 (12)BEN 92 (110)XYL 6 (12)

f

MV-7A9

MW~3fli OCE 10 (17)TCA 12 (8)TCE 9 (12)

DCE 13 (14)TCE 120 (110)

-*'I HYDRANT

> c 16TH AVENUE r -u u

1.

1-.L-LJC.I iJ

9 MONITORING WELL LOCATION5.8 CONCENTRATION OF FIRST ROUND (MICROGRAMS/LITE(11) CONCENTRATION OF SECOND ROUND (MICROGRAMS/l1.10 1.1 DICHLOROETHANEDCE 1,2 DICHLOROETHENE (TOTAL)DCA 1.2 DICHLOROETHANE

J<l

aM

:R)JTE

TCA 1.1.1 TRICHLOROETHANETCE TRICHLOROETHENEBEN BENZENEXYL XYLENES

NO NO VOLATILES DETECTED

- ~

- \\\\\\ \\ -v1

- \\V- \\\\D NO (5)

" * *DCE 10 (12)1 " ' " " MW .= iCA 5 (7)T MV-15 ^ TCE 39 >45j

Mv-n1 AT W FIGURE 4-2rpr T7O /ccfrt J.UUI\C. «t C.

DCE u (21) VOLATILE CONTAMINATIONR) IN GROUND WATER

i UNION SCRAPT MINNEAPOLIS, MINNESOTAI

NORTH PROJECT MO. PREPARED ft A

0 ^^^° 11-89-185 BDO/PR ^Ki

soui-ftEr °*TC 1Q/5/89 ""g^1" ^J^^

DeltaCoiwultonta. IfM.

Contaminant

1,1 • Dichloroethane

1,2 - Dichloroethene(total)

12 - Dichloroethane

1,1,1 - Trichloroethane

TrichlOFoethene

Benzene

Xylenes (total)

TABLE 4-7

Volatile Organic Contamination In Ground WaterUnion Scrap Iron and Metal Company


Concentrations (nj/T)

An«*t7. 1989 Anmst 10. 1989

95

1417211212

1113

87

110121265032045

110

12

MW-7MW-15

MW-3MW-7MW-13MW-14iMW-15

MW-10MW-14s

MW-7MW-15

MW-3MW-7MW-10MW-13MW-14sMW-15

MW-10

MW-10

6ND

1310141010

611

125

12091237026039

92

6

ND - Not detected at or above MDL

Uw.102

Remedial Investigation ReportUnion Scrap Iron aod Metal Company1608 Waihiogtoa Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 9

Benzene and xylenes were found only in MW-10. Benzene ranged from 92 to 110 ug/1 while xylenesranged from 6 to 12 ug/L

Several orgaak compounds were found in opgradieat monitoring wells MW-14s and MW-ia Three

compounds; trichtoroethene 1,2 - dichloroethene; and 1,2-dichloroethane; were found in MW-14. 1,2 -Dichloroethane, trichloroethene, benzene, and xykaes were found in MW-10. Table 4-8 lists the

contaminants at the two upgradient (MW-14* and MW-10) and two downgradient (MW-13 and MW-15)

wells. Only 1,1 - dichloroethane and 1,1,1 • trichloroethane were not detected at the upgradient wells,

but were present on site and downgradient in MW-15.

The concentrations of 1,1 - dichloroethane and 1,1,1 - trichloroethane range from 5 to 9 ug/1 and 5 to

12 ug/1 per liter, respectively. The concentration of both contaminants are slightly higher on site at MW-

7 than in MW-15, downgradient. Therefore, 1,1 • dichloroethane and 1,1,1 - trichloroethane appear tobe originating from the Union Scrap site; however, these compounds were not detected in on-site soil

samples. Consequently, the source of these organks is not known. If a source exists on the site, it

appears to be of limited extent and magnitude.

Semlvolatite Contamination

All seven monitoring wells were sampled twice for 65 semivolatile organic compounds. No semrvolatile

compounds were detected in the ground water beneath the Union Scrap site. Semrvolatile results are

presented in Appendix O.

* 4.3 J Polrchlorlnated Blphenrl Con*a"*if*atk)ii

For the two rounds of ground water samples collected during August 1989, PCB analyses were performed

on samples from all seven monitoring weDs. Ground water samples collected for PCB anlayses on

September 19, 1989 were only from monitorial wete MW-7, MW-10, and MW-15. Table 2-2 lists the

seven PCB compounds included in these analyses. Arochlor-1248 was detected at 0.9 ug/1 in the ground

water sample collected on August 7, 1989 from MW-7. However, no PCBs were detected at MW-7 or

any other well from the August 10, 1989 samples (Figure 4-3).

Contaminant Concentrations at Upgradient and Downgradlent WellsUnloo Scrap Iran and Metal Company

Minneapolis, MinnesotaDelta No. 114M85

DowngradlentConcentration at

MW-13and 15(ue/l)

1.1 - Dichloroetnane

1.2 - Dichloroethene (total)

1,2 • Dichloroetnane

1,1,1 - Trichloroethane

Trichloroethene

Benzene

Xylenes

MW.lt aid 14*

<5

10-12(only MW-14* )

6-13

<5

12-320

92-110(only MW-10)

6-12(only MW-10)

5

10-21

<5

5 - 7(only MW-15)

39-650

<5

<5

<5 * Method Detection Limit

klw.905

ND (ND)MW-14D

ND (ND)MW-14S

GRASSYAREA

a

UJ

u

aal—«

VJ

SIGNE - Z STOP

CONVENIENCE STDREPARKING LDT

-MV-10* ND (ND) [ND]

PCB 12480.9 (ND) [ND]

MV-7 A

MW-3ND (ND) '

HYDRANT

-t-16TH AVENUE

•t-

LEGEND.••'

Q MONITORING WELL LOCATION

ND PCB-S NOT DETECTED IN AUGUST 7. 1989 SAMPLES

(ND) PCB'S NOT DETECTED IN AUGUST 10, 1989 SAMPLES

[ND] PCB'S NOT DETECTED IN SEPTEMBER 19. 1989 SAMPLES

0.9 CONCENTRATION OF DETECTED PCB (ug/l)

9 ND (ND) [ND]

ND (ND)

NORTH

FIGURE 4-3POLYCHLORINATED BIPHENYL

CONCENTRATION IN GROUND WATERUNION SCRAP

MINNEAPOLIS, MINNESOTAPROJECT MO.

11-89-185OATC

PREPARED BY

BDQ/PRBY Delta


Sample information forms (Appendix N) indicate that the water samples from MW-7 contained sediments.

Additionally, laboratory analyst notes indicate that the entire sample, including water and sediments, was

extracted and analyzed. This laboratory extraction procedure would remove any PCBs attached to

sediment and place them into the extract solution. Consequently, any PCBs attached to sediments in the

well, but not necessarily in the aquifer water, would show up in the analysis. Referring back to Table4-4, low levels of PCBs were found in several sofl samples. Drilling operations may have carried sediments

with attached PCBs into the ground water and they are now showing up from sediments remaining in

MW-7. Because residual well construction sediments could have caused the original detect in MW-7 and

because the second sample showed no detectable PCBs, a third set of samples was collected duringSeptember 1989.

The September 19,1989 ground water samples were obtained from monitoring wells MW-7, MW-10, and

MW-lS. Four ground water samples were collected from each monitoring well. The first sample was

collected usinjj a bailer and analyzed for PCBs using the same sampling methodologies as the first two

rounds of samples. The analytical results of these three samples reported nomietectablc concentrations

of PCBs at or above the detection limit of (X5 mg/L

Subsequent to the collection of the first bailed ground water sample, three samples were collected using

a teflon bladder pump. Water was pumped from the well until the well was stabilized and the water was

clear of sediment The discharge hose was connected to the sample container and the container was filled.

Following the collection of the first sample, water was pumped from the well for 15 minutes until thenext sample was collected. These nine sample* from the three monitoring wells were anlayzed by a

modified 608 (PCB) analysis to achieve a lower method detection limit of 0.05 ug/1. None of the nine

samples contained concentrations of PCBs at or above the method detection limit

4J.4 Inorganic Contamination

4J.4.1 Cvanide

All seven monitoring wells were sampled twice tot cyanide. Cyanide was not detected in any of the

samples above the detection limit of 10 ug/L

Remedial Investigation ReportUnion Scrap Iron and Meul Company1606 Wubinftoo Avenue NorthMinneapolia, MinnesotaDelta No. 11-89-185Page 11

4J.4.2 Common Ground Water Constituents

Several of the inorganic analytes on the metals list tie commonly found in ground water. These analytes

or cations are aluminum, calcium, iron, magnesium, manganese, potassium, and sodium. The

concentrations of these cations found in the two rounds of ground water samples are presented in Table

4-9.

In general, the two rounds of ground water sample* collected from the six shallow monitoring wells and

the deep monitoring well are both calcium dominated with sodium and magnesium as the second and third

most common cations. Differences between the shallow and deep ground waters can be seen in the

concentrations of the cations. The shallower ground water has higher dissolved concentrations of the

calcium, potassium, magnesium, and sodium cations. Aluminum and iron concentrations are higher in the

deeper ground water.

These cation concentrations were compared to a ground waier sample from the metropolitan area wiih

similar hydrogeology. The ground water sample used for comparison is a sample from a spring located

in St. Paul along the Mississippi River (MPCA, 1965). The concentrations of this "background" ground

water sample are listed on Table 4-9. Calcium concentrations from the St. Paul spring and deep water

sample are similar. Magnesium concentrations are lower in the shallow and deep ground water than in

the spring water sample. Potassium concentrations are a little higher than in the spring water sample

but are still in the same range. The deep ground water samples had sodium concentrations similar to

the spring water, however, the shallow ground water concentrations were significantly higher.

The cation concentrations in the shallow ground water are higher than those found in the St. Paul water;*

however, these concentrations are uniformly higher (Le. npgradient, on site and downgradient). These

higher concentrations may be indicative of natural shallow ground water chemistry in this area or may be

due to the land use in the area. Specific conductivity data also agrees between our observations at the

Union Scrap site and the "background* ground water.

4J.4J Trace Analvtes

Sixteen trace analytes are presented in Table 4-9 along with the common ground water constituents

discussed above. These trace metals occur naturally in ground water. Trace metal concentrations in

TABLE 4-9

aummaij <K inorpUUC KODII!Union Scrap Iron and M

Minneapolis, MlnDelta No. 11-89

CiuiMntrat

Anolvte

Aluminum

Antimony

Arsenic

Barium

Beryllium

Cadmium

Calcium

Chromium

Cobalt

Copper

Iron

Lead

Magnesium

Manganese

MDL

40.7

50.8

10

4.9

1.4

4.8

21.0

9.8

110

3.6*

9.1

3.0

24.0

1.6

SampleRound

12

12

12

12

12

12

12

12

12

12

12

12

12

12

Deep WellMW.14d MW-Mi

<87.02290

NDND

NDND

125126

NDND

NDND

125k126k

NDND

NDND

NDND

679775

NDND

42k43.4k

10701120

<104<95.0

60.057.0

NDND

375302

NDND

NDND

255k234k

NDND

NDND

NDND

ND

NDND

583k60.6k

11701010

MW.10

<87.0

NDND

NDND

218210

NDND

NDND

146k154k

102ND

ND14.5

NDND

ND133

NDND

50.1k52.4k

33503680

i in uronnetal Compnesota-185

ton* (ag/l)

MW-3

<66.0<67.0

ND53.0

NDND

152142

NDND

NDND

187k196k

NDND

NDND

NDND

NDND

NDND

462k48.1k

12302040

ia waterany

MW.7

< 113.0<76.0

NDND

NDND

214236

NDND

NDND

162k162k

NDND

NDND

NDND

NDND

NDND

39k39.4k

9511010

MW-13

<78.0

56.0610

NDND

250231

NDND

NDND

207k204k

NDND

NDND

NDND

ND<13.0

NDND

533k54.7k

677716

SL PaulMW-15 Sample •

NA<88.0

ND910

ND 1000ND

247 91218

NDND

ND 0.1ND

195k . est. 150k190k

ND 1ND

NDND

ND 2ND

ND 160ND

ND 1ND

NA 210k48.7k

931 60854


Analyte MPL

Mercury 0.2

Nickel 12.9

Potassium 1360

Selenium 5

Silver 4.8

Sodium 776

Thallium 10

Vanadium 4.8

Zinc 3.5

SpecificConductivity

PH

TcmpcQttnc *«

SampleRound

12

12

12

12

12

12

12

12

12

12

12

12

Deep WeUMW-l4d

NDND

<19.0<14.0

ND3&30

NDND

NDND

2&2k26,4k

NDND

NDND

26.0<1&0

10001000

1313

12«C13-C

MW.141

NDND

<31048.0

11.4k12.0k

NDND

114<5.7

147k145k

NDND

NDND

<15.044.0

20701900

7.0d8

YfC14«C

MW-10

<a4oND

5&067.0

76308550

NDND

<54ND

162k168k

NDND

NDND

<14.0<14.0

16001600

6464

14«Cl+C

MW.3

NDND

48.065.0

76108160

NDND

<4.8<5.1

157k165k

NDND

NDND

<19.0<16.0

17001700

6.76,8

14°C13°C

MW-7

NDND

<18.0<38.0

iaik10.4k

NDND

ND<6,1

933k92.7k

NDND

NDND

<11.0<13.0

13901200

6.965

12°C15«C

MW-13

NDND

<29.0<22.0

57305800

NDND

<5.9ND

151k154k

NDND

NDND

<17.024.0

17001700

646.9

13°C14°C

MW.1S

NDND

<30.04ao

12k12.4k

NDND

NDND

139k135k

NDND

NDND

<17.0<19.0

17001600

7.06.7

12°C14°C

SL PaulSample •

100

3

4.1k

4

37.4k

2

1375

6.8

15°C

MDL » Method Detection Limit NA - Not analyzed due to laboratory accident- - m Means not analyzed or reportedk - Value x 1000ND - Not detected at or above MDLSpecific conductivity units as omhos/cm2

°C - degrees celcius* Ref: Minnesota Pollution Control Agency, Division of Solid and Hazardous Waste, June 1985, Ground Water

Quality Monitoring Program: A Compilation of Analytical Data Collected from 1978 to 1984.< » Modified method detection limit

Remedial Investigation ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149-185Page 12

natural waters may range from a few tens of mkrograms per liter to a fraction of a microgram per liter(Hem, 1985).

These trace anahytes were also compared with the St. Paul spring water chemistry where data was

available. In several cases, the spring water sample had lower concentrations of an anaryte than the

detection limit listed on Table 4-9. This occurred for cadmium, chromium, copper, lead, nickel, selenium,

and zinc. In all these cases, except for chromium, nickel and zinc, a 'not detected* (ND) was reported

by the laboratory (Table 4-9). For these "(ND)* metals, the detection limits are close to the

concentrations found in the spring water indicating that shallow and deep ground water at the Union

Scrap site have similar or lower concentrations than the spring water sample. For nickel and zinc, the

concentrations are a little higher than the spring water sample but are in the same range. Zinc

concentrations range up to 42 ug/l and are within the range of zinc concentrations for natural waters of

5 to 45 ng/1 reported by Hem, 1985. Chromium was detected in only one well, MW-10 at 102 ug/L This

is within the same range and only slightly above the value reported for the St. Paul spring water.

Concentrations in the shallow ground waters were lower for arsenic and mercury than the spring sample.

Site ground water concentrations of arsenic and mercury are below the detection limits of 10 and 0.3 ug/l,

respectively.

Barium concentrations in shallow ground water across the site are slightly higher although in a similar

range to the concentration in the St. Paul spring water.

*

Finally, four trace anah/tes that were not reported in the St. Paul spring are cobalt, silver, thallium, and

vanadium. Thallium and vanadium were not detected in any monitoring wells at detection limits of 10

ng/1 and 4.8 ug/l, respectively. Cobalt was detected only once in MW-10 at 14.5 ug/L Silver was detected

in Gve of the sfat shallow monitoring wells at concentrations ranging from 4.8 to 12.4 ug/L Silver was not

detected in downgradient well MW-15 or in the deep well MW-144.

433 Summary of Ground Water Contamination

No organic contamination was detected in the deep well All shallow monitoring wells showed some

volatile organic contamination. Seven volatile organics were detected in ground water. These organics

are trichloroethene, 1,2-dichloroethene, 1,2-dichloroethane, 1,1-dichloroethane, 1,1,1-trichloroethane,

benzene, and xylenes.

Remedial Invotlntioo ReportUnion Scnp Iron and Meal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelia No. 1149-185Page 13

The highest concentrations of trichlorethene were (bond in MW-14s upgradient from the site and MW-

13 sidegradient and south of the site (Figure 4-4). The tricbJoroethene concentrations decrease in a

downgradient direction from northwest to southeast The source of this trichlorethene contamination in

ground water is not known; however, it is not originating from the Union Scrap site.

Concentrations of 1,2 - dichloroethene range from 10 to 21 ug/L 1,2 - dichloroethene is found in all

shallow monitoring wells except MW-10. The concentrations of 1,2 • dichloroethene are in a similar range

in all wells where it is found; however, the highest concentration was found in cross gradient well MW-

13, off site to the south (Figure 4-2).

1,2 - Dichloroethane was detected only in upgradient wells MW-10 and MW-14. The highest

concentrations found was 13 ug/l in MW-14s.

1,1 - Dichloroethane and 1,1,1 - trichloroelhane were found in on-site well MW-7 and in downgradient

well MW-15. There is no evidence of these compounds in on-site soils although they could be present

in soils between the deep soil sample and ground water table. If present, the concentrations are expected

to be low as no volatiks were detected during hNu field screening. The limited extent and low

concentrations do not suggest extensive contamination from these compounds.

MW-10 lies on the north central side of the site. It was placed at this upgradient position to help define

ground water quality moving beneath the site from the north. Benzene and xylenes are found only in

MW-10 and were not found in any on site soils. It appears these compounds are migrating from an

upgradient source and did not originate at the Union Scrap site. Benzene concentrations ranged from 92

ug/l to 110 ug/l and xylenes from 6 ug/l to 12 ug/L

No semivolatile compounds were detected in ground water samples from the site. The detection limit

of the semivolatile compounds for ground water range from 10 to SO ug/L

One PCB, Arochlor • 1248, was detected at 0.9 ug/l in MW-7 during the first round of ground water

sampling. The contaminant was not detected at or above the detection limit of 0.5 ug/l in the second or

4/

4,

4 - 4 ^

E - Z STOPCDNVIENIENCE STORE

PARKING LOT

MW-10

4, GRASSY 4,AREA

^^ w ^»^

4, 4, 4,

4, 4, 4,

\^ ^^ ^^

^^ ^^ ^»^

^^ ^^ ^^LEGEND

• i * ^^ \*

«M 13 MONITORING WELL LOCATION

(370) TRICHLOROETHENE CONCENTRATION <UG/L>AUGUST 7, 1989

——— TRICHLOROETHENE CONTOUR LINE

39) e MV-15

NORTH

FIGURE 4-4TRICHLDRDETHENE CDNCENTRATIDN

CONTOUR MAP (AUGUST 7, 1989)UNION SCRAP

MINNEAPOLIS, MINNESOTAPROJECT NO.

11-89-185DATE

10/5/89

PREPARED m

BDD/PRBIT Delta

Consultant*. IM.


third set of ground water samples from this well The source of this compound in the first ground water

sample is suspect, due to the presence of sediment in the sample, and because of the lack of confirmation

of the PCBs in later samples. The contamination in the MW-7 water sample may have been derived from

the sediment in the well associated with monitoring well construction. Since the three confirmatory

samples showed no detectable PCBs in MW-7, PCBs are not deemed to be present in the ground water

at the Union Scrap site.

The inorganic analytes consisted of 23 metals and cyanide. The presence of these inorganics in ground

water samples taken from all six monitoring wells were compared with ranges in a spring water sampletaken near St. Paul These analytes occurred in ground water at concentrations that are generally within

ranges similar to natural waters, although some variation between surQcial ground water samples, samples

from MW-14d, and the spring water sample were noted.

4.4 Conclusions

4.4.1 Volatile Organics

Volatile organics were detected in two soil samples at low concentrations. Tetrachloroethene was detected

at 6 ug/kg in boring B-5, the deep sample. Trichloroethene was detected at 11 ug/kg in the shallow

sample from boring B-7. The trichloroetheoe source is shallow and was not detected in deeper soil

samples within the same boring. The trichloroetheoe source appears limited in extent and magnitude and

does not appear to be impacting ground water. Tetrachloroethene was detected in the deep sample in

boring B-5 but not in the shallow samples. Tetrachloroethene was not found in any ground water samples.

Therefore, the source of tetrachloroethene is expected to be of limited extent and magnitude and will not

impact ground water at concentrations of concern.

Shallow ground water in the area is impacted by volatile organics; however, only 1,1 • dichloroethane and

1,1,1 • trichloroethane may be originating from the Union Scrap site. All other parameters are found

only at upgradient locations, Le., benzene, xylene, and 1,2 - dichloroethane, cr are found at upgradient

locations as well as throughout the area, Le., 1,2 - dichloroethene and trichloroethene. These volatile

organics do not appear to originate from the Union Scrap site.

Remedial Investigation ReportUnion Scrap Iron and Meul Gompaoy1606 WvhinftoD Avenue NorthMinneapolis, MianeaocaDelu No. 11-89-183Page 15

1,1 • Dichloroethane was found in low concentrations in only two wells: on-site well MW-7 anddowngradknt well MW-15. No 1,1 • dkhloroethane was found in site soils. This compound may be abreakdown product of 1,1,1 - trichloroethane. There does not appear to be a significant or continuingsource of the contaminant at the Union Scrap site.

1,1,1 - Trichloroethane was found in only two wells in low concentrations: on-site well MW-7 anddowngradient well MW-15. It was not found in site sofls. No significant source of this contaminant isapparent at the Union Scrap site; however, it does appear to have migrated with the ground water toMW-15.

4.4.2 Polvchlorinated BvphenvU

One PCB (Arochlor -1248) was found at low levels in site sofls. PCS contamination of subsurface soilsdoes not appear to be significant nor widespread. No consistent pattern or downward migration trendswere evident in soils and PCBs were not found above method detection limits in the ground water. Onesurface water PCB sample indicates surface contamination originating from off-site sources.

4.4J Inorganic Analvtes

The common metals and trace metals are present in site soils and concentrations similar to natural soils.Inorganic analytes are also found in site ground water at concentrations that are generally within rangessimilar to natural waters.

5.0 CONTAMINANT FATE AND TRANSPORT

5.1 Potential Routes of Migration

Potential routes of contaminant migration at the Union Scrap site include air, surface water runoff,

infiltration through the vadose zone, and ground water Oow transport. The two primary routes of concern

at the Union Scrap site are infiltration through the vadose zone and ground water flow transport Air

and surface water runoff are considered negligible doe to the backfill which was placed over the entire

site after the EPA Removal Actions in 1968. The backfill limits the contact of any remaining

contaminated surface soil with the atmosphere and surface water.

5.2 Physical/Chemical Properties

The physical and chemical properties of compounds are important indicators of fate and transport in the

environment These characteristics include solubility, volatility, specific gravity, soil/water partitioning (soil

adsorption), biodegradation pathways, and chemical reactivity. This section presents a brief discussion

of the physical and chemical properties potentially affecting contaminant migration at the Union Scrap

site.

Solubility is important in gronndwater contamination and pollutant transport Solubility is a measure of

the amount of a substance which can dissolve m a solvent, in this case water. Compounds with high

solubility in water move with the water and thus, may move considerable distances and affect large areas.

Solubility is usually expressed in terms of milligrams (mg) of a compound per liter (1) of water. These

units, mg/1, are equivalent to parts per million (ppm).

Volatility is an indication of a substance's tendency to evaporate or transform from the liquid phase to

vapor phase. Volatility is frequently measured or gauged by a compound's vapor pressure. Vapor pressure

is defined as 'the pressure of vapor above the liquid or solid phase of a substance at equilibrium* (Boikess

and Edebon, 1981). The .higher the vapor pressure a substance exhibits, the easier it is for that substance

to evaporate. Vapor pressure is usually expremed in terms of millimeters (mm) of mercury. One

atmosphere of pressure is equal to 760 mm mercory. Vapor pressure b important to consider when a

dissolved compound is exposed to air. If the compound has a high vapor pressure, it b more apt to move

into the vapor (air) phase than if it had a lower vapor pressure.

A better indicator of a compound's ability to volatflhe out of solution b the Henry's Law constant (H).

It b expressed in units of atmosphere cubic meters per mote (atm • m3/mole). The derivation of H

includes a term for the compound's solubility in water. Therefore, it b an excellent method to predict

volatility of a compound dissolved in water. The larger the H, the more volatile the compound. The

Remedial Investigation ReportUoioo Scrap Iron and Metal Company1606 Washington Avenue NorthMtnneapotia, Minn*""**Delta No. 1149-185Page 2

more volatile compounds have Henry's couuntt in the range of 10** to 10"5 aun - m3/mole. Semivolatiles

range from 10"3 to 10"5 atm-m*/mole. A compound is considered to have low volatility when H is equal

to 10"* atm-m3/mole or less.

The specific gravity of a substance is the ratio of the mass of a substance to the mass of an equal volume

of water. The specific gravity of water if defined as 1.00 gram per cubic centimeter (gm/cm3). A

substance with a specfic gravity greater than LOO wffl tend to sink in water. Those substances with a

specific gravity less than 1.00 will float on top of the water. The usefulness of specific gravity is greatest

when large or bulk amounts of a substance encounter water. Small quantities of a substance will continueto dissolve until the substance is totally dissolved or the maximum solubility is reached.

An important parameter, in terms of a substance's mobility, is the soil/water partitioning coefficent (Koc).

This value is an indication of a compound's affinity for adsorption to soils and organic material A

molecule of a substance with a high Koc wfll tead to bind or adsorb to a soil particle more than if it

had a low Koc. Compounds with a low Koc will tend to stay in solution in water. The Koc has units

of mOliliters per gram (ml/g). The Koc for a substance in a medium such as soil is dependent on the

organic content and the amount of fines, Le. sflts, and clays in the soil

Biodegradation can affect a sustance's environmental persbtance and, indirectly, its mobility. A substance

is biodegradable if it is capable of being decomposed by natural biological processes. In sofls and ground

water, this usually occurs through bacterial activity. Biological degradation can occur in aerobic

(oxygenated) or anaerobic (without oxygen) environments. The oxygen avaOibOity can determine the

exjent that a compound wfll decompose and the tine it takes for decomposition to occur. Anaerobic

degradation usually takes more time than aerobic degradation. Knowing how a compound breaks down

allows scientists to determine rates of degradation and longevity of a substance in the environment

Additionally, biological breakdown products nay end up being more or less mobile than the original

compound.

Chemical reactivity is also important for many of the same reasons as biodegradation. Chemical reactivity

is the tendency of a substance to participate in chemical reactions. The physical state that a substance

is found in environment and the time period that a compound exists is dependent on chemical reactions

Remedial Investigation ReportUnion Scrap Iron and Meul Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-49-185Page 3

that it can undergo with water (hydrolysis), sunlight (photooxidation), and other chemicals that may bepresent

The term "half-life* is frequently used to quantify how persistent a chemical is in the environment under

a given set of circumstances. The half-life of a compound is defined as the time period that elapses

before that substance degrades to one-half its original concentration. This time period is dependent on

the degradation pathway and environmental conditions and can vary significantly from one compound toanother.

At the Union Scrap site, six compounds of potential concern were found in soil and ground water samples.

These are: lead, 1,1 - dkhloroethane, 1,1,1 • trkhloroethane, trichloroethene, tetrachloroethene, and PCBs.

Specifically, 1,1- dichloroethane, 1,1,1-trichloroethane and trichloroethene were found in the ground water.

Trichloroethene, tetrachloroethene, lead, and PC3s were found in the soil

A brief summary of the chemical and physical properties for the organic compounds is presented in Table

5-1. The properties are also discussed in the following subsections.

5.11 Lead

Lead occurs in the environment in many different forms. The forms used in lead-acid batteries, which

were processed at the site, are primarily elemental lead and lead oxides (Sax, 1987).

Elemental lead is a heavy, ductile, soft, gray solid (Sax, 1987). The oxides are also solid and range in

color from yellow to red, brown, and black. la general, these compounds are nonvolatile and insoluble

in water, but dissolve in acid. If deposited onto sofl, lead adsorbs to organic matter and clay materials

which limit its mobility.

S.2.2 LL1. Trichloroethanc

1,1,1- Trichloroethane a a colorless, synthetic solvent used for metal degreasing (Sax, 1987). This

compound can be a contaminant of trichloroetbeae (Verschueren, 1983). 1,1,1-Trichloroethane is very

soluble in water (4400 mg/1 at 20*C). The vapor pressure, which is 100 mm of mercury at 20°C, suggests

that this compound would readily volatilize. The soil/water partitioning coefficent (K^) is 152 ml/g. It

TABLE 5-1

Union Scrap Iron and Metal Company

Organic

1,1.1 -trichloroethane

1,1 • dichloroethane

trichloroethene

tetrachloroethene

polychlorinatedbiphenyls(Arochlor 1248)

Solubility InWater fmg/n

4,400

5,500

1.100

150

0.04 - 0.2

1(08 Washington AvenueMinneapolis, Minnesota

Delta No. 11-89-185

Henry'sVMMW fnmiftmnt*~t~" -u-uwwiii

rrmars (atm-nr/mole)(•BtfBO at 25*C

100 0.0276

180 a0057

60 a00892

14 0.0227

0000077 .00107

SpedOcGravityWater - LOO*

135

1.174

1.46

1.626

1.41

Kocml/g

152

30

.126

364

530.000

VisualDescription

colorlessliquid

colorlessliquid

colorlessliquid

colorlessliquid

strawyellow

* All properties at 20°C, unless otherwise statedReferences;

FbrPCBs: USEPA, (1986).

For all other compounds: Venchoeren, K. (1983).

kry.N21

Remedial Investigation ReportUnion Scrap Iron ud Metal Company1608 Washington Avenue NorthMinneapolis MinnesotaDelu Na 1149-185Page 4

is noted that this value is considered fairly low. Thus, 1,1,1-trichloroetbane has a relatively low affinity

for adsorbing to organic matter. The specific gravity for this compound is US making it heavier than

water and the compound will tend to sink in water.

LI- Dtehloroethane

1,1- Dichloroethane is a synthetic, colorless, ofly ud flammable organic compound used primarily as a

cleaning solvent and degreaser. It is abo (bud at an intermediate in the synthesis of other chemicals,

principally 1,1,1 - trichloroethane. 1,1- Dkhloroethane b extremely soluble in water (5500 mg/1 at 20°C).

In addition, this compound has a vapor pressure of 180 mm of mercury at 20°G This is considered fairly

high and thus, this compound will readily volatilize. The soil/water partition coefficent is 30 ml/g. This

value is one-fifth the value for 1,1,1-trichloroethaae and is considered low. Thus, 1,1- dichloroethane has

a low affinity for adsorbing to organic matter and soils, and is considered mobile in ground water. The

specific gravity for this compound is 1.174. As sock, 1,1-dkhloroethane is heavier than water and wfll tend

to sink in an aqueous environment.

5.2.4 Trichloroethene

Trichloroetbene is a synthetic, colorless solvent vied as a degreasing agent in the metal industry. This

compound can also be a degradation product of tetrachloroethene (Parsons et aL, 1984).

Trichloroethene is fairly soluble in water (1,100 mf/l at 20°Q The vapor pressure b 60 mm of mercury

at 20°C This compound is volatile but would not tend to volatilize to the same extent as 1,1,1-

trichloroethane and 1,1-dichloroethane. It b similar to 1,1,1- trichloroethane in that it has almost the

same soil/water partition value. The specific gravity of trichloroethene b 1.46. This compound b heavier

than water and wfll tend to sink if found in aqueous environments.

Tetrach teroethene

Tetrachloroethene b a synthetic solvent that hat been used extensively in industry as a metal degreasing

agent and in the dry cleaning process. Tetracaloroetbene has a solubility of 150 mg/1 which b lower than

the three previously discussed chlorinated compounds. It abo has the highest Koc value (364 ml/g). This

indicates that tetrachloroethene wfll bind to organic matter more readily than the other compounds.

Remedial Investigation ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthVflnoeapoik, MinneaotaDelta No. 1149-185Page5

The vapor pressure is fairly low, however, the Henry's constant is similar to trichloroethene.

Consequently, this compound is relatively mobile in soU and water (e.g^ infiltration, ground water

movement). The specific gravity of tetncUoroethene is 1.626. This compound is heavier than water

and will tend to sink if present in aqueous environments.

5.2.6 Porvchlorlnated BlDhenvii (PC**)

PCBs were used extensively in the electrical industry as coolants in transformers and capacitors.

Commercial PCBs are mixtures of different congeners of chlorinated biphenyls and have varying chlorine

contents. Congeners are compounds whkh resemble each other in their nature and chemical properties.

Chlorinated biphenyl congeners have similar structures, but differ in the number and locations of the

chlorine atoms. PCB molecules contain from one to ten chlorine atoms, thus •polychlorinated' biphenyjs

(Clayton, 1982). Arochlor and Kanechlor are commercial trade names for PCB mixtures.

In general, PCBs 'are thermally stable, very resistant to degradation, and resistant to oxidation, acids,

bases, and other chemical agents. PCBs are soluble in most of the common organic solvents and lipids,

but only slightly soluble in water, glycerol, and glycols' (Clayton, 1982). Typically, PCBs adsorb to soil

particles and have low volatility. However, the physical and chemical characteristics of a particular PCB

mixture depends on its degree of chlorination. Generally, the greater the chlorination, the less soluble

the compound. The persistence of PCBs in the environment seems to increase as the degree of

chlorination increases.

One commercial PCB, Arochlor 1248, was identified at the Union Scrap site. This PCB mixture has a

low water solubility ranging from 0.04 to (X2 mg/l The vapor pressure and Henry's constant are also low

aj*.000077 mm/Hg and 0.00107 atm - m*/mote, respectively. Arochlor 1248 b heavier than water with

specific gravity of 1.41, and the Koc is 530JOOQ

5.3 Contaminant Persistence and MobOltr

Several factors and measurable characteristics are important in discussing environmental persistence and

mobility. These factors include the physical ud chemical properties for the compounds of concern and

amounts of organic matter and silts and clays in the affected environmental media. At the Union Scrap

Remedial Invettintka ReportUnion Scrap Iron ud Metal Company1608 Washington Avenue NorthMinneapolis, MinnocxaDelta No. 1149-185Page 6

site, there are two media of concern: subsurface sofl and ground water. This discussion is limited to the

effects of these processes on contaminant characteristics in those media.

SA2 Lead

This compound was detected in sofl samples collected from the Union Scrap site. As an element, leadis an extremely stable metal and persists indefinitely in the environment Soils and sediments may act asa sink for removal of lead from other environmental media such as surface water, ground water, or air.

If released to soil, lead will form insoluble complexes with organic matter and clay minerals that will limitits mobility. Also, an inert coat of insoluble salt wfll form over the exposed surface of the pure metal andinhibit corrosion (USEPA, 1984). Lead generally remains 'in the upper 2 to 5 cm of soil, especially soilswith at least 5% organic matter or a pH 5 or above* (HSDB, 1989). Depending on the type of soil, thelead slowly forms insoluble sulfate, sulfide, oxide, and phosphate salts. Near the surface, lead attachedto organic materials or soils may be transported with runoff to surface water and deposit with sediment,or become airborne as dust in the atmosphere.

Certain microorganisms can incorporate lead into organic compounds. For example, some microorganismsare able to directly methyiate certain inorganic lead compounds (USEPA, 1977). This does not degradethe lead but incorporates it into the molecular structure. In this example, methyl groups (CHj) attachto lead. In this form, the lead will be more mobile as the molecule has more of the characteristics of anorganic molecule than of elemental inorganic toad. This reaction is reversible, therefore, elemental leadand lead ions can still be present in solution. Although lead itself has a very low vapor pressure and isessentially nonvolatile, tetramethyl lead wfll volatilize quite readfly (HSDB, 1989).

*

SJJ LL1. Tttehlofotthane

This compound was detected in ground water samples collected from the Union Scrap site. In groundwater, this compound tends to move fairly coosistmtry with ground water flow, although it has someaffinity for adsorption to sofl particles and organic natter. Some biodegradation or hydrolysis may occur

in ground water, but at a relatively slow rate. "Degradation may take several weeks and acclimation isimportant* (Bouwer, 1983).

Remedial Investigation ReportUnioa Scrap Iran and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-183Page?

If 1,1,1- tricbJoroethane is discharged with groond water to surface water, concentrations would be reduced

through dilution. 1,1,1- Trichloroethaoe is not persistent in surface water due to volatilization to the

atmosphere (IRIS, 1989). The surface water half-life ranges from "hours to a few weeks depending on

wind and mixing conditions' (Wakeham, 1983).

Once in air, 1,1,1- trichloroethane is fairly stable, at h is relatively slow to degrade and has a half life of

six months to 25 yean (Callahan. 1979). The degradation that does occur through reaction with hydroxyl

radicals is increased in the presence of chlorine radicals and nitrogen oxides. In addition, '15% of the

1,1,1- trichloroethane drifts into the stratosphere where it is rapidly degraded by photodissociation.'

(Battelle, 1977). The unreacted portion of 1,1,1- trkhloroethane concentrations in air are reduced by rain,

which dissolves and returns some of the 1,1,1-trichloroethane to surface soib. Photooxidation products

would likely include hydrogen chloride, carbon oxides, phosgene, and acetyl chloride.

SJ.4 LI- Dtehloroethane

This compound was detected in ground water samples at the site. 1,1- Dichloroethane will likely be more

mobile in the ground water than 1,1,1* trichloroethane. This is due to its high solubility and low affinity

for adsorption.

Data are not available regarding the half-life of 1,1- dichloroethane in ground water. Biological

degradation of this compound has been observed uder anaerobic conditions. However, it is not expected

to be a major degradation pathway. In fact, *No (bio)degradation was detected when 1,1- dichloroethane

was incubated with uncontaminated samples of subsurface material taken from positions immediately above

and below the water table at Pfckett, Oklahoma, and Fort Polk, Louisiana* (HSDB, 1989).««

If 1,1- dichloroethane is discharged with grand water to surface water, dilution and volatilization would

be expected to reduce its concentration quite rapidly. This is because the compound has a relatively high

Henry's constant Doe to volatilization, its half-life hi ponds, lakes and rivers is estimated at 6.4-9.4 days,

5.1-7.5 days, and 24-32 hours, respectively (HSDB, 1989).

Remedial Investigation ReportUnion Scrap Iron and Metal Company1606 Waihteftoo Avenue NorthMinneapolis, MinneaotaDelta No. 1149-185PageS

1,1-Dichloroethane is not persistent in the environment In the atmosphere, the compound will disperse.

Some photochemical degradation will also occur a* 1,1- dichloroethane reacts with photochemicalry

produced hydroxyl radicals (half-life - 62 days) (HSDB, 1989).

Trlchloroethtng

As noted, trichloroethene was detected in one sod sample from the Union Scrap site. Experiments have

shown that the adsorption of trichloroethene to toils is dependent on the content of organic matter in

the sediments. Coarse gravels showed little adsorption relative to higher organic content soils, (i.e., peat

soil) (Callahan, 1979). The evidence concerning adsorption of trichloroethene to soil particles has beenconflicting and inexact

Trichloroethene is fairly soluble in water. This, along with a low K^ value, suggests that trichloroethene

can be mobile in soils and may eventually reach ground water, where it would migrate with the ground

water flow. In the vadose zone, a 'significant amount of the trichlorccthene is expected to be present

in the soil-water and soil-air phase, and thus available to be transported through these phases by bulk

transport (e.g.t the downward movement of inffltrating water), dispersion, and diffusion* (AMD, 1985).

Biological degradation of trichloroethene in aquatic systems has been deemed possible by researchers.

However, as a synthetic compound, trichloroethene is not naturally found in the environment Thus,

microbial degradation requires a long acclimation period to allow the microorganisms time to develop the

appropriate enzymes to cleave the bonds in the trichloroethene molecule. In addition, this process requires

anaerobic conditions.*

+

This compound has a fairly large Henry's Law constant and thus, may volatilize through air died soil

pores in soils near the surface. Additionally, trichloroethene discharging to surface water with the flow

of ground water would volatilize into the atmosphere. Upon entering the atmosphere, trichloroetheae

can undergo any of a number of oxidation pathways to form endproducts of hydrochloric acid, carbon

monoxide, carbon dioxide, and a chlorinated carboxytk acid. These reactions occur rapidly, the expected

atmospheric half-life of tricbloroetheoe is approximately 4 days (Callahan, 1979).

Remedial Investtiation ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 9

SJ.< Tetrachloroethene

Tetrachloroethene was found in one soil sample collected at the site. Experimental data for soiladsorption of tetrachloroethene correlates with the results highlighted for trichloroethene. Adsorptiveproperties of the molecule varied with the organic content of the media. It was noted that coarse gravelswith low organic content adsorbed smaller amounts of tetrachloroethene than did more organic soils. (e.g.,peat)(Callahan, 1979) Tetrachloroethene is soluble in water, yet not as soluble as trichloroetbene. Thiscompound has a Koc greater than trichloroethene. However, tetrachloroethene would be expected to beleach from the soils and migrate with ground water flow.

Biological degradation of tetrachloroethene is considered possible by researchers, but not likely. As withtrichloroethene, tetrachloroethene does not naturally exist in the environment It is a synthetic compound.Long periods of time are required for the microorganisms to develop enzymes which will allow forbiodegradation to occur. As with the other compounds already discussed, anaerobic conditions are neededfor biodegradation.

If exposed to the atmosphere via discharge with ground water to surface water or through transportthrough air filled pores in shallow soils, the main mode of transport, volatilization, will occur. Oncevolatilized into the atmosphere, tetrachloroethene undergoes oxidation reactions similar to those involvingtrichloretbene. The endproducts of these reaction ate hydrochloric acid, carbon dioxide, carbon monoxide,and a chlorinated carboxylic acid. The atmospheric half-life of tetrachloroethene is estimated at 10 days

1979). It has a longer half-life thai trichloroethene due to the presence of four chlorine atomson the molecule, which hinder the oxidation reaction.

««

5.3.7 PCBl

Arochlor 1248, a mixture of relatively highly chlorinated PCB congeners, has been detected in soil samplesat the Union Scrap site. Generally, PCBs are not very mobile through soils. One reason is that higher-chlorinated congeners adsorb more tightly to tod particles. The large Koc value (530000 ml/g) and lowwater solubility (0.04 - 0.2 mg/I) tend to mmiaifae the movement of Arochlor 1248 with water through

soils.

Remedial Inveuintkxi ReportUoioo Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolb, MboeaotaDelta No. 1149.185Page 10

Although PCBs are not very volatile, the total lots of PCBs from soil and water "by volatilization over

time may be significant because of the persistence and stability of PCBs' (HSDB, 1989). Volatilization

rates are higher for the lower chlorinated PCBs, in part, because they adsorb less tightly to organic matter

aad are more free to migrate. However, in water, the majority of PCBs wfll adsorb first to organic matter

in the sediment and suspended particles. Gradual desorption and subsequent volatilization to air may be

a major removal mechanism for PCBs from surface water (Swackhamer, 1986).

Degradation of PCBs in soil may occur through a biological pathway. With the exception of

biodegradation, no degradation mechanisms "have been shown to be important in natural water and soil

systems' (HSDB, 1989). Biodegradation also is greatly dependent on the degree of chlorination of the

PCS. The various PCB congeners have differing biodegradation rates. "Mono, di, and trichlorinated

biphenyls (Arochlor 1221 and 1232) biodegrade relatively rapidly, tetrachlorinated biphenyls (Arochlors

1016 and 1242) biodegrade slowly, and higher chlorinated biphenyls (Arochlors 1248,1254, and 1260) areresistant to biodegradation' (HSDB, 1989). Although the higher-chlorinated congeners biodegrade very

slowly, the lack of other degradation mechanisms leave biodegradation as "the ultimate degradation process

in water and soil' (HSDB, 1989).

PCBs reaching ground water are not generally subject to hydrolysis or oxidation. In surface water, PCBs

"have been shown to bkxoncentrate significantly in aquatic organisms' (HSDB, 1989).

Volatilized PCBs, whether from surface water or sofls, in the atmosphere may react and transform, orreturn to Earth. Between 87% and 100% of atmospheric PCBs exist primarily in the vapor phase. As

noted in Table 5-1, the vapor pressure of Arochlor 1248 is 7.70 x 10*5 mm Hg. The vapor pressure of

any given PCB varies inversely with the degree of chlorination. Higher chlorinated PCBs are more likely

to be associated with participates in air than lower chlorinated compounds. Paniculate-associated PCBs

wfll eventually return to Earth in a process called dry deposition. Vapor-phase PCBs in air may undergo

transformation through reaction with bydroxyi radicals. The estimated half-life for this type of reaction

also depends on the degree of chloriaation of the PCB. Half-lives range from "12.9 days for

monochlorobiphenyl to 1.31 yean for heptachlorobipbenyl" (HSDB, 1989). PCBs not transformed will

eventually deposit through wet deposition with rain. As a result, 'the PCS concentration of rain anywhere

in the world may typically range between 1 and 250 nanograms per liter (ng/1)' (Eisenreich, 1981).

Remedial Investigation ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 1149.185Page 11

5.4.1 Site CondMoni

Understanding the migration, transport and ultimately the fate of the site derived contaminants requires

evaluation of site specific geologic and hydrogeologic conditions in concert with contaminant characteristics

and behavior in the environment The following discussion is a brief review of the major findings of the

RI presented in Section 3.0 which are important in the evaluation of the migration, transport and fate of

contaminants.

The site is underlain by a sand and gravel unit which is approximately 50 feet thick. The water table ispresent in this unit at a depth of approximately 30 feet The ground water flow direction in this unit is

generally to the southeast with a hydraulic gradient of 0.0005 feet/foot Estimates of the hydraulic

conductivity of the surficial sand range from 110 • 283 cubic feertquare foot-day. Estimates of the ground

water flow velocity within the unit ranged between 0.16 feet/day and 0.48 feet/day. The primary ground

water flow component was assumed to be horizontal based on the presence of the relatively impermeable

clay unit beneath the water bearing unit and knowledge of the discharge area. The discharge area of the

surficial sand and gravel unit is believed to be the Mississippi River. Infiltration of rain water through

the vadose zone would be relatively rapid, given the coarse nature of the soils. The infiltration rate would

be dependent on soil moisture content, amount of rainfall, and soQ stratification.

As stated, the Mississippi River is considered the discharge area for the surficial sand and gravel unit

underlying the site. No shallow ground water weDs (above the clay layer) were identified between the site

and the river in the direction of ground water flow. Therefore the river is assumed to be the next

environmental receptor of contaminants observed in the ground water at the Union Scrap site. Assuming

the surficial sand and gravel unit is continuous to the river and has similar geologic and hydrogeologic

properties as defined at the site, it is calculated that ground water from the site would reach the river in

approximately 103 yean. This was determined by using the highest calculated flow velocity of 0.48

feet/day and a distance of 1,800 feet to the river following the observed flow direction at the site.

The geologic and hydrogeologic descriptions and the results of these calculations will be used in

discussions in the following sections.

Remedial ^n"ettltrth*ii ReportUnioo Scrip Inn and Meul Company1606 Washington Avenue NorthMinneapolis, MinnnaotaDelta No. 11-89-185Page 12

5.4.2 Lead

As noted in Section 132, the upper one to three feet of sofl was removed during EPA Emergency

Removal Actions in 1988. Samples collected during the Removal Action showed lead concentrations at

the surface of up to 66,800 mg/kg, with decreasing concentrations with depth. Within a few feet of thesurface, lead concentrations were found to be approximately 300 mg/kg.

Lead concentrations measured in soils at the site during the RI were found to be within a range

considered normal (0 - 200 mg/kg • USEPA, 1983) tot most soils. The highest observed lead concentration

was 102 mg/kg in the shallow sample collected from boring B-6. The soils at the site consist of sand with

very little organic matter (Le., silts and clays). The percentage of fines (soil particles passing through a

200 micron diameter sieve) make up less than 6 percent of the total soil As such, it would be expected

that lead would be relatively mobile. However, samples from boring B-6, the location of the highest

measured lead concentrations, showed decreasing levels of 6.7 mg/kg and 13.9 mg/kg at the intermediate

and deep sample intervals, respectively. In addition, ground water analyses have revealed no detectable

amounts of lead present It b apparent that the lead contamination at the site due to past activities hasbeen removed.

From this data, it is concluded that lead contamination in soils at the site due to past activities has been

successfully remediated to levels that are considered normal Further, the data indicates decreasing

concentrations of lead with increasing sofl depth. Thus, the future threat of lead contamination to groundwater is minimal

This compound was observed on site in well MW-7 at 12 and 8 ng/L Concentrations of 5 and 7 ug/l were

observed in well MW-15. MW-7 is located on the eastern portion of the site, and MW-15 is off-site and

downgradient from the site approximately 120 feet 1,1,1 • Trichloroethane was not detected in any sofl

sample, either on site or off site.

Remedial Inveitintton ReportUnioo Scrip Iron and Metal Company1606 Washington Avenue NorthMinneapotk, MmoeaotaDelta No. 11-89-185Pap 13

No continuing source of 1,1,1- trichloroethane is suspected at the site. This compound has relatively high

solubility in water. Along with a low Koc value, these parameters indicate that this compound will very

likely migrate with the ground water in the water bearing unit Further migration and dispersion will

result in dilution. Assuming the source of 1,1,1 • tficUoroethane is on site near MW-7, the effects of this

are already evident in comparing the concentrations in MW-7 and MW-1S. The concentration of this

compound is also expected to decrease slightly by means of biodegradation and attentuation through

adsorption to organic matter. A possible degradation product b 1,1- dichioroethane, which has been

detected in the same ground water samples as 1,1,1* trichloroethane.

It is not anticipated that a detectable mass of 1,1,1 • trichloroethane will be discharged to the Mississippi

River with ground water. Any remaining concentrations of 1,1.1- trichloroethane discharged to the river

will be further diluted and subsequently volatilize to the atmosphere. Molecules of 1,1,1-trichloroethane

in the atmosphere will eventually undergo photodegradation.

5.4.4 1.1- Dichioroethane

Results from two rounds of ground water sampling showed there were detectable amounts of 1,1-

dichloroethane in MW-7 and MW-1S. Concentrations of 6 and 9 ug/l were found in on-site well MW-

7. 1,1 - Dichioroethane was detected once at • concentration of 5 ug/l in MW-1S. As noted in Section

5.43 above, MW-7 is located on the eastern portion of the site and MW-1S is located off-site and

approximately downgradient of MW-7. 1,1 • Dichioroethane was not detected in any soil samples.

Therefore, no continuing source of 1,1 • dichioroethane is suspected at the site.

Due to the high water solubility and relatively tow Koc value for 1,1- dichioroethane, it is likely that this

compound will migrate within the ground water. The contaminant mass will likely be slightly decreased

by biodegradation. Although biodegradation of this compound is slow, the long residence time for the

contaminant in the water bearing unit, about tea yean, should allow for some biodegradation. In

addition, it is believed that the concentratkm of this compound will decrease with distance from the site

though dispersion, dilution and, to a minor degree, adsoption to organic matter. This is already evident

by comparing the 1,1- dichioroethane concentrations in MW-7 with those from the downgradient MW-

15.

Union Scnp Iron and Metal Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelu No. 11-89-185?»ge 14

It b not anticipated that a detectable man of 14 - dfchtoroethane will discharge with the ground water

to the river. Any 1,1- dkhloroethane that it discharged to the Mississippi River will first be diluted with

river water then volatilize into the atmosphere where photodegradation wfll occur.

Trichloroethenc

Trichloroethene was detected at a concentration of 11 ug/kg in the shallow sofl sample collected from

boring B-7.

Trichloroethene is relatively mobile in sofls. The sand and gravel underlying the site do not likely contain

a high amount of organic matter. As such, the adsorptivity of trichloroethene in this sofl would be

relatively low and this compound would tend to teach into the ground water via infiltration. However,

slight attenuation due to adsorptivity would reduce the mass of contaminants as leaching occurs.

It is not anticipated that the contaminant mass wfll volatilize from the sofl to the atmosphere because of

the location of the mass below ground surface (approximately 2 feet). It is noted that trichloroethene was

not detected in the intermediate or deep sofl samples collected from this boring. This indicates that the

site is not a source of trichloroethene contamination to ground water.

The relatively small, discontinuous mass of trichloroethene identified in the shallow sofl sample at B-7 is

not expected to provide, through leaching, a detectable contaminant mass of this compound in the ground

water. Abo, ground water beneath the site was found during the RI to be affected by an unknown,

upgradient trichloroethene source. The magnitude of trichloroethene concentrations from the unknown

source are much higher than any trichloroetheae which may be leached from on site sofls.

If traces of this compound leach to the groaad water, the mass would be diluted through dispersion and

attenuation. Any trichloroethene discharged to the Mississippi river via ground water would be further

diluted and would eventaaDy volatilize to the atmosphere where it would undergo photodegradation.

5.4.6 Tetradikifoethene

Tetrachloroethene was detected at a concentration of S ug/kg in the deep sample collected from boring

B-5. This compound was not detected in the ground water.

Remedial IfTvtttitfl^QQ ReportUnion Scrap Iron and Metal Company1606 Waihin|ton Avenue NorthMinneapolis, MmnetotaDelta No. 11-89-185Page 15

Like trichloroethene, this compound is relatively mobile and would tend to leach from the soils underlying

the site. Slight attenuation would occur with vertical migration. The relatively small amount of this

compound that was noted in B-5 had not and is not expected to provide a detectable mass of

tetrachloroethene in the ground water.

Should traces of this compound teach to the frond water, the mass would travel with the ground water.

The mass would dilute with distance from the site fin dispersion and attenuation. Any tetrachloroethene

discharged with ground water to the Mississippi River would be further diluted and would eventually

volatilize to the atmosphere where it would undergo photodegradation.

S.4.7 PCBs

One PCB, Arochlor 1248, was observed in sofl samples collected from three sofl borings at the site.

Results indicated 120 ug/kg in the shallow sample from boring B-4, 220 ug/kg in the shallow sample from

boring B-8,1000 ug/kg in the deep sample from boring B-8, 94 ug/kg from the shallow sample in boring

B-10, and 200 ug/kg from the duplicate of this sample.

The PCBs present in the soil are not expected to move. PCBs have a high affinity for soil particles and

a low water solubility. Thus, water infiltration thromfh the soils will not cause appreciable leaching of

the PCBs to the ground water. Volatilization of PCBs to the atmosphere is not likely since the

contaminated zones are covered with a minimum of one to three feet of clean sofls.

All monitoring wells were sampled on two occasions in August and monitoring wells MW-7, MW-10, and

MW-15 were sampled a third time in September. Arochlor 1248 was detected at 0,9 ug/1 in the first

sample from MW-7. The second and third samples from this same monitoring well had no detectable

levels of this compound. The samples collected from upgradient wells MW-10 and MW-15, which lie

downgradient of MW-7, did not yield any detectable levels of PCBs. Consequently, PCBs have been

determined not to be a contaminant in the grond water at the Union Scrap Iron and Metal Company

site. Therefore, the presence of PCBs in the sofl does not appear to have affected the ground water

quality beneath the site. However, as stated previously, PCBs do exist at the site and whOe they are

presently immobilized on subsurface sofl particles, they win remain immobilized only as long as the soil

particles themselves remain immobilized.

TABLE t-2

Concentration of Pollutants hi Aquatic Organisms at BqalUbriomUnion Scrap Iron and Metal Company

Minneapolis, MinnesotaD*tta No. 11.8M8S

Pollutant BCF/a Cw fn«/r> /b Cao fua/te^ /c D fug/ka/davl /d

1,1 - Dichloroethane U M 09 1.17 5.0 x Iff4

1,U - Trichloroetnane 5.6 /f U 6.72 W

/a Bioconcentration factor

A> Concentration of the pollutant in water

/c Concentration of the pollutant in aquatic organism

/d Dose on average each day for an average person

It from the National Library of Medicine's Hazardous Substance Data Bank file on 1,1 • DCA

/f from the Superfund Public Health Evaluation Manual, USEPA, EPA/54CV1-86VD60 (USEPA, 1986b)

Remedial Investigation ReportUnion Scrap Iron and Metal Company1606 WtthiD|too Avenue NorthMinueapotit, MinneaouDelta No. 1149.183Page 10

impaired function of these organs may be adversely affected by exposure to the compound (NIOSH, 1981).

Human health effects from exposure to lower levels of this compound have not been well documented.

However, 'rats, guinea pigs, rabbits, and cats tolerated 6-hr daily exposures to 500 ppm (in air) for 13

weeks (5 days/week) with no adverse effects* (Claytoa. 1982). Also 'Rats, guinea pigs, rabbits, and dogs

were exposed to either 500 or 1000 ppm for seven boon per day, five days per week, for six months.

Gross microscopic pathological and hematological studies showed no evidence of changes attributable to

the exposure" (Clayton, 1982). Therefore, 1,1 • dicUoroethane is not believed to be a human carcinogen.

Like 1,1-dichloroethane, 1.1,1-trichloroeihane is also a CNS depressant at high concentrations. Exposure

of animals to concentrations to lower concentrations (between 500 and 10,000 parts per million of 1,1,1-

trichloroethane in air) resulted in decreased body weight gain, fatty changes in the liver, and increased

liver weights (Adams, 1950; Torkebon, 1958).

Based on the available human and animal data, 1,14-trichloroethane is classified as a U.S. EPA GroupD compound. According to this rating system, compounds in Group D are not classifiable as to human

carcinogenicity. In the case of 1,1,1-trichloroethane, the compound is not classifiable because "no reported

human data and animal studies (one lifetime gavage, one intermediate-term inhalation) have demonstrated

carcinogenicity. Technical grade 1,1,1-trichloroethane has been shown to be weakly mutagenic, although

the contaminant, 1,4-dioxane, a known animal carcinogen, may be responsible for this response' (IRIS,

1989). Therefore, 1,1,1 - trichloroethane alone is not believed to be a human carcinogen.

<.L4 Risk Characterization

Risks for carcinogens and non-carcinogens are evaluated differently. Risks for exposure to carcinogens

can be compared to one in one million. If risks of exposures to carcinogens are greater than one in one

million (1 x 10*), then health risks are said to be elevated. By contrast, risks for exposure to non-

carcinogens (1,1,1 - trichloroethane and 1,1 • dkhtoroethane) can be compared to a number known as the

reference dose (RfD). A reference dose is a level at which people can be exposed to a non-carcinogenic

toxicant and not experience adverse health effects.

Remedial Investigation ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMinneapolis MinnoantaDelta No. 11-89-185Page 11

Health risks are calculated on the assumption that members of receptor populations will be exposed to

a given level of a contaminant continuously over a 70 year lifespan. Standard methodologies have not yet

been adopted for calculating risks from exposures of shorter durations.

Risks from Ground Water Exposure

The Minnesota Department of Health (MDH) Recommended Allowable Limits (RAL) for 1,1-

dichloroethane and 1,1,1-trichloroethane in drinking water are set at 810 ug/I and 200 ug/1, respectively

(Table 6-1). The USEPA has set a Maximum Contaminant Level (MCL) and a MCL Goal (MCLG)

for 1,1,1 - trichloroethane in drinking water of 200 ug/1 (Table 6-1). All measured concentrations of both

1.1 - dichloroethane and 1,1,1 • trichloroethane are below these drinking water limits. In addition, the

contamination appears to be limited to the shallow aquifer in this area, which is not generally used for

drinking.

However, as a worst case scenario, assume that people use this shallow ground water for drinking and

bathing. Assume also that the water consistently contains 1,1-dichloroethane at 9 ug/1 and 1,1,1-

trichloroethane at 12 ug/l, and that only 20% of the total dose is from ingestion and the rest of the dose

resulted from inhalation or absorption during showering. A total contaminant dose can be calculated

using Equation 6-4 (USEPA, March, 1987).

D - (Cw x W / B)/.2 (Equation 6-4)

where: D - Dairy dose from ingestion, absorption, and inhalation (ug/kg/day)

Cw « Concentration of contaminant in ground water (ug/1)W - Water ingested per day ( 2 I/day)B - Body weight (70 kg)2 • factor adjusting dose for only 20% of the exposure resulting from ingestion of the water

Using Equation 6-4, the dose of 1,1-dichJoroetBue would be 13 ug/kg/day, and the dose of 1,1,1-

trichloroethane would be 1.7 ug/kg/day. The oral reference dose (RfD) for 1,1,1-trichloroethane in

humans, based on no adverse effects in female guinea pigs (the most sensitive species), is 90 ug/kg/day

(IRIS, 1989) No reference dose is currently available for 1,1-dichloroethane. However, these compounds

Remedial Invotitatiop ReportUnion Scrap Iron and Metal Company1608 Waibinftoo Avenue NorthMinneapoia, MinnesotaDelta No. 1149-185Page 12

have similar physical and chemical properties, structures, and lexicological effects. Assuming they have

similar mechanisms of action in humans and that their health effects could be additive, daily exposure

doses for the two compounds could abo be added Car a total of L3 + L7 » 3.0 ug/kg/day. The total is

still an order of magnitude below the RID for 1,1,1-trichloroethane alone and therefore there would be

negligible health risks posed by exposure to 1,1-dkhloroethane or 1,1,1-trichloroethane in ground water

from the site.

Risks from Fish Consumption

As noted earlier, the Minnesota Department of Health has issued Gsh consumption advisories for allspecies except pan Gsh from Little Falls to St. Anthony Falls, just downstream from the Plymouth Avenue

Bridge. Fish consumption advisories have abo been issued for all species of Gsh in the Mississippi River

from St Anthony Falls (approximately 1 mile downstream from the Union Scrap site) to the Iowa border.

The Minnesota Department of Health recommends that restricted Gsh constitute no more than one meal

per month (MDH, 1989). However, for the purposes of this risk assessment, it wfll be assumed that the

fishing population eats 30 grams (l.OS ounces) of fish per day.

Risks to populations catching and eating Gsh can be estimated using results from Equation 6-5. Using

Equation 6-3 and assuming water concentrations of 0.9 ng/1 1,1-dkhloroethane and 12 ug/l 1,1,1-

trichloroethane (one tenth maximum ground water* concentrations due to dilution and mixing in the river),Gsh are estimated to contain 1.17 ng/kg 1,1-dfchloroethane and 6.72 ug/kg 1,1,1-trichloroethane (Table 6-

2). The dairy dose of pollutants for a person (70 k|) who catches and eats 30 grams of Gsh each day can

be calculated using Equation 6-5 (USEPA, 1986).

D - (CaoXFyW (Equation 6-5)

where: D - dose (ug/kg/day)Cao • concentration of the pollutant in aquatic organismF » Gsh consumed on average each day (0.030 kg/day)W • weight of an average person (70 kg)

Using this equation, people would be exposed to approximately 5.0 x 10"4 ug/kg/day of l,l-4ichk>roethane,

and 2.9 x Iff3 ug/kg/day of 1,1,1-trichloroethane (Table 6-2). According to the EPA's electronic database,

IRIS, the oral reference dose (RfD) for 1,1,1-trichloroethane a 9 x 104 mg/kg/day, or 90 ug/kg/day. As


discussed above, the RfD is the level at which people can be exposed to a non-carcinogenic toxicant, like1,1,1-trichloroethane, and not experience advene health effects. The estimated exposure dose of 19 x

Iff3 ug/kg/day of 1,1,1-trichloroethane b leu than to RfD of 90 ug/kg/day.

Although an ore] reference dose a not currently available for 1,1-dichloroethane, 1,1-dichloroethane b

estimated at lower concentrations than 1,1,1-trlchlofoethane and as discussed in 6.1 J.I, is also less toxic.

Even if the doses of 1,1-dichloroethane and 1,1,1-trichJorocthanc were added for a total of 3.0 x 10°

ug/kg/day, the sum is more than three orders of magnitude less than the reference dose of 90 ug/kg/day,

and therefore, fish consumption should pose no increased health risks.

Finally, estimated contaminant doses for U-dichlofoethane and 1,1,1-trichloroethane from consumption

of contaminated ground water (13 and 1.7 ug/kg/day, respectively) are several orders of magnitude larger

than estimated doses from fish consumption (5.0 x Iff4 and 19 x 10*3 ng/kg/day, respectively). Even ifthe doses of both compounds in ground water aad in fish were added, the total (3.0 ug/kg/day) would still

not exceed the RfD for 1,1,1-trichloroethane alone (90 ug/kg/day).

Risks from Surface Water Exposure

The last potential receptor population to evaluate consists of people who use the Mississippi River for

drinking water. As noted earlier in this section, according to a representative of the Minnesota

Department of Natural Resources, no other Minnesota communities have drinking water intakes

downstream from Minneapolis. The not intake is located in Iowa at least one hundred mOes south ofMinneapolis. Since 1,1-dkbJoroethaae and 14tl-trichloroethane concentrations on site are already below

Minnesota Recommended Allowable Limits by seven) orders of magnitude, and since these concentrations«

will reduce even farther with time and distance, contamination from the site should not increase health

risks for downstream populations.

In summary, the human health assessment presented above has shown there is negligible potential for

increased public health risks from exposure to 14-dfchloroethane or 1,1,1-trichloroethane from this site.

4v2 Environmental Assessment

As noted in Section 6.1.11, on-site air releases of 1,1-dichloroethane and 1,1,1-trichloroethane are unlikely

Remedial Inveitintion ReportUnion Scrap Iron and Metal Company1608 Washington Avenue NorthMtaoeapotii, MinoeaouDelta No. 1149-185Page 14

to be significant since the subsurface soil contamination is low in concentration, limited in extent, and

covered with two to three feet of clean soil Dissolved contaminants may move in the ground water, or

as a worst-case scenario, discharge with the frond water to the Mississippi River. Assuming also as

wont-case scenario that 1,1-dichloroethane and 1,14-trichloroethane will discharge to the Mississippi river,

fish could be exposed to these volatile, water-soluble compounds.

Federal Ambient Water Quality Criteria for Aquatic Tenacity are currently not available for the

contaminants of concern. However, the State of Minnesota has set an aquatic toxicity-based number for

1,1,1-trichloroethane of 138 ug/l, which is less than the Minnesota Department of Health's Recommended

Allowable Limit for Drinking Water of 200 ug/L An aquatic toxicity-based number is not currently

available for 1,1 -dichloroethane. However, the maximum combined concentration of 1,1,1-trichloroethant

and 1,1-dichloroethane in the ground water on site (21 ug/1) is lower than the criteria for 1,1,1-

trichloroethane alone (Table 6-1). As shown in Section 6.1.Z2, combined concentrations of 1,1 -

dichloroethane and 1,1,1 - trichloroethane may be at least as low as 9.9S x 10*5 ug/I after mixing in the

river. At this level, contaminant concentrations would not be high enough to produce adverse effects on

populations of fish or other aquatic organisms.

As noted in Chapter 5, air is the ultimate depository for any molecules of contaminants that have not

degraded by the time the plume reaches the river. Estimated concentrations of 1,1 - dichloroethane and

1,1,1 - trichloroethane from the Union Scrap rite n the river water are estimated to be in the 4 x 10'5

to 6 x 10~5 ug/1 range, undetectable with current laboratory techniques. These compounds have relatively

high Henry's constants, and with agitation in the river, will gradually volatilize to the air. However, air

concentrations are likely to be lower than water concentrations since volatilization is a gradual process

and since the contaminants would undergo dispersion and degradation in the air. Since the estimated river

water concentrations are so low, concentration* of 1,1 - dichloroethane and 1,1,1 - trichloroethane from

the Union Scrap site in the air above and around the river would be insignificant and unmeasurable. It

is likely that the concentrations would also be orden-of-magnitude less than the proposed acceptable

ambient levels in air, drafted by the Air Quality Division of the Minnesota Pollution Control Agency in

October 1989 (Table 6-1). Therefore, air is not likely to be advenly affected by migration of contaminants

from the Union Scrap site.

Union Scrap Iron and Metal Company1*08 Washington Amue NorthMinneapolis, MinnesotaDelta No. 1149-185Par 12

63 Risk Assessment Summary

Current on-site groood water concentrations of 1,1-dfchloroethane and 1,1,1-trkhloroethane are below

levels that would pose increased human health risks. Estimated concentrations of these contaminants in

surface water and in fish are also below levels of human health concern. Environmental risks are also

negligible, since concentrations of 1,1-dkhloroethane and 1,1,1-trichloroethane currently beneath the site

are already less than drinking water standards and available water quality criteria for aquatic toxicity

(Table 6-1). Therefore, due to the low levels of the estimated human and environmental risks, further

remedial actions at the site are not

4.0 BASELINE RISK ASSESSMENT

This chapter evaluates human health and environmental risks posed by migration of compounds from the

Union Scrap site. The chapter is divided into three major sections, a public health evaluation, an

environmental assessment, and a summary section. The public health evaluation discusses chemicals of

concern and presents an exposure assessment, a tenacity assessment, and a risk characterization for those

chemicals. The environmental assessment evaluates possible impacts of site chemicals on the surrounding

environment and on associated animals, fish, or other organisms. The summary reviews the conclusions

of the public health evaluation and the environmental assessment

6.1 Public Health Evaluation

The public health evaluation is based on the chemical, physical, and lexicological characteristics of the

chemicals present in soil and ground water at the site, and the potential for human exposure to chemicals

migrating from the site. In order for compounds from the site to pose a public health risk, two conditions

must be satisfied. Pint, there must be at least one completed exposure pathway. Inhalation of vapors

or contaminated dust in air, absorption of compounds in water or dust through the skin, or ingestion of

chemicals in soil or water are all examples of completed exposure pathways. Secondly, the contaminant

concentrations that humans are exposed to most be high enough to pose a health risk.

The public health evaluation is divided into four main sections: indicator chemicals; an exposure

assessment; a toxkity assessment, and a risk characterization. The indicator chemical section discusses

which compounds were included in the risk assessment and why they were chosen for evaluation over other

chemicals. The exposure assessment interprets the future movement of indicator chemicals in the

environment, and estimates their concentration at potential receptor populations. The toxkity assessment

reviews the available literature on the toxic effects of exposure to various concentrations of the indicator

chemicals. Finally, the risk characterization evaluates potential health risks from estimated exposure

concentrations. These concentrations are compared to drinking water and ambient water quality criteria

limits set by the Minnesota Department of Health (MDH) and the US. Environmental Protection Agency

(USEPA). The MDH and EPA limits are set at levels believed to be low enough to protect the public

from adverse health effects. The limits also provide a scale by which potential health risks can be

measured.

6.1.1 Indicator Chemicals

For sites with a large group of contaminants, the selection of indicator chemicals directs the focus of the

risk assessment toward the most toxic, persistent, mobile, or prevalent compounds in the group, and limits

Remedial Invettinttoo RecoctUnkxi Scrap Iron and Meal Company1606 Washington Avenue NorthMinneapolif, MinixaotaDelta No. 11-89-185Page 2

the attention given to compounds of less concern. At the Union Scrap site, several volatile compounds,porychlorinated biphenyb (PCB*) and metals have been detected in the soQs and/or ground water beneath

the site. However, as discussed in Chapters 4 and 5, only the presence of 1,1-dichloroethane and 1,1,1-

trichloroethane in the ground water, and lead, trkUoroetheae, tetrachloroethene, and PCBs in the soil

appear to be due to past activities at the site.

Of these six compounds, only 1,1 • dkhloroethane and 1,1,1 - trichloroethane are included in this risk

assessment. Lead is not included since as discussed in Chapter 5, EPA emergency removal actions in 1988

successfully remediated soil lead concentrations to levels considered normal Also, since lead was not

detected in ground water beneath the site, the lead remaining in the soO does not pose a threat to public

health or the environment

Although trichloroethene was also detected in sofl and ground water on site, it is not included in the

risk assessment for several reasons. Pint, trichloroethene was detected at low levels (11 ng/kg) in only

one shallow soil sample (Table 4-3), and it was not detected in deeper soils at any location (detection limit

of 5 ug/kg), indicating that the soil is probably not contributing to the identified trichloroethene

contamination in ground water beneath the site. Abo, although trichloroethene was detected in the ground

water beneath the site (Table 4-7), it is present in higher concentrations in upgradient and off-site wells

(Figure 4-4). Figure 4-4 shows that a plume of trichloroethene may be affecting ground water qualitybeneath the site, but that given the ground water flow direction, the site is not the likely source of

trichloroethene contamination.

Tetrachloroethene and PCB* abo are not included in the risk assessment Tetrachloroethene is not

included because it was found in only one deep sofl sample (Table 4-2) at 5 ug/kg (equal to the detection

limit), and was not detected in any of the ground water samples (detection limit of 5 ug/1). While PCBs

were detected at concentrations ranging from 120 ug/kg to 1,000 ug/kg in subsurface son (Chapter 4, Table

4-4), these concentrations are below the RCRA PCB-deanup criteria of 10 mg/kg (40 CFR, Part 761).

PCBs were not detected in the ground water beneath the site. Due to their chemical and physical

properties, the remaining PCBs are not expected to leach appreciably from on-site soils to ground water

and therefore are not included in the risk i

Remedial Investigation ReportUnioo Scrip Iron and Metal Company1608 Washington Avenue NorthMiooeapotit, MumeaotaDelta No. 11-W-18SPage 3

All the other compounds for which analyses were performed were either detected at levels typical ofnatural soils or are present in ground water doe to migration of contamination from upgradient sources

(not associated with site operations) onto the Union Soap site (see Section 42S).

6.L2 Exposure Assessment

The exposure assessment uses information presented in Chapter 5 to estimate any possible human intake

of contaminants from the site. Based on the estimated human intake and the toricity of the contaminants,

human health risks can be characterized. Human receptors and exposure point concentrations are

discussed in the following sections.

The only pathways for exposure to contaminants from this site are associated with ground water and

surface water. Migration of contaminants through soil is not a significant concern since the site has beencovered with two to three feet of dean fin tad, as discussed in Chapters 4 and 5, contaminant

concentrations in soil are low and of limited extent Air releases are also not a significant concern at the

site since a significant quantity of contaminants are unlikely to volatilize from subsurface soils or from the

ground water and travel through thirty feet of sofl, to the air. Therefore, the only possible human

receptors are those that could be exposed to frond water or surface water that may be impacted by

contaminants from the site.

Ground Water Receptors

figure 2-3 shows the location of the identified wefls within a one mile radius of the site. Since the

ground water is moving to the southeast towards the river, none of the wells are located directly in the*

projected path of ground water flow from the site, The four closest downgradient wells are located at

least 2,000 feet south southeast of the site and are screened at depths of 300 to 400 feet (Table 2-1).

Drillers logs indicate the presence of a discontinuous day zone which may act as a partial barrier to

contaminants migrating from the shallow ground water. Due to the presence of the clay layer, the

horizontal distance to the wells, the depths and the location of the wells, persons using water from these

wells are unlikely to be exposed to contamination from the site.

Remedial InvoUntioo ReportUnioe Scrap Iran and Metal Company1606 Washington Avenue NorthMnneapolit, MtanaaouDelta No. 11-89-185Pace 4

However, it is possible that not all wells in the area were identified. If a well was located down gradientfrom the site, and screened in the surficial sands and gravel, it could be affected by contaminants from

this site. Due to the hypothetical nature of this scenario, the size and characteristics of this potential

human receptor population cannot be defined.

Surface Water Receptors

The shallow ground water beneath the site will eventually discharge to the Mississippi River. Ground

water in deeper aquifers will likely be controlled by pumping in the Prairie du Chien aquifer during much

of the year and may not move in the same direction as the surficial aquifer (Chapter 3). Abo, ground

water sampling results indicate that water quality in the deep aquifer appears to be unaffected by activities

at the site. Therefore, the shallow ground water is most likely to affect the water quality of theMississippi River.

Ground water bom the site b projected to discharge to the Mississippi River near the Plymouth Avenue

bridge, above St. Anthony Falls. Since the drinking water intake for the City of Minneapolis is

approximately 1.5 miles north of the Union Scrap site (upstream), ground water from the site will not

affect the city's drinking water supply. According to a representative of the Minnesota Department of

Health, no other communities in Minnesota have drinking water intakes on the Mississippi, downstream

from Minneapolis. The next downstream drinking water intake is in Iowa at least 100 miles south ofMinneapolis.

Fish Consumption Receptors

Near the Plymouth Avenue bridge (the projected ground water discharge point), the river is not generally

used for swimming. However, people may catch and eat fish from this area of the river. The Minnesota

Department of Health has issued fish consumption advisories for all species except pan fish from Little

Falls to SL Anthony Falls, just downstream from the Plymouth Avenue Bridge. Pan fish are not restricted

in this section of the river since they tend to be toner, less long-lived fish and consequently, contaminant

concentrations in their tissues are generally tower than concentrations in other species of fish.

Ground water currently beneath the Union Scrap the will eventually discharge to this portion of the river.

If contaminants discharge to the river with the gro«nd water, fish in the area could ingest and retain these

Remedial Invdrimton ReportUnkxi Samp Iron and Metal Company1606 Watfainftoo Arame NorthMinneapoJa, MimwaocaDelta No. 1149-185PageS

compounds. People who catch and eat the fish could in torn be exposed to these same compounds.

In summary then, there are three potential human receptor populations: the hypothetical ground water

users; Mississippi River water drinkers at the Iowa border, and people who catch and eat fish from this

portion of the river. In the following section, the concentrations of contaminants at the points of exposure

for the three human receptor populations wffl be estimated.

4.1.2.2 Exposure Point Concentration Estimate (fate!

In this section of the report, concentrations of site contaminants at potential receptor populations are

estimated by projecting the movement of the contaminants over time and distance. Again, the three

exposure points arc the ground water between the site and the river, the fish in the river near the ground

water discharge point, and a drinking water intake at the Iowa border on the Mississippi River.

Ground Water Concentrations

No wells art known or suspected to exist between the site and the river along the projected path of

ground water migration. However, as a worst case scenario for exposure, it will be assumed that a

drinking water well is screened in the contaminated aquifer midway between the site and the river. Also,

it will be assumed that the soluble, volatile contaminant concentrations in the ground water beneath the

site (1,1-dichloroethane and 1,1,1-trichloroethane) do not change (through adsorption, degradation,

dispersion, etc.) as the plume moves towards the river. The exposure point concentration then, for 1,1-

dichloroethane and 1,1,1-trichloroethane in ground water at any downgradient location would be the same

as the maximum concentrations on site (up to 9 ug/l for 1,1-dichloroethane, and up to 12 ug/l for 1,1,1-

trichloroethane).

*

Both of these maximum concentrations are well below the Recommended Allowable Limits (RALs) for

their respective compounds (810 ng/l for 1,1-dichloroethane and 200 ug/l for 1,1,1-trichloroethane) set by

the Minnesota Department of Health (MDH) (Table 6-1). The Federal Maximum Contaminant Limit

(MCL) for 1,1,1 • trichloroethane is the same level at Minnesota's RAL for this compound. An MCL for

1,1 - dichloroethane has not been established. The federal Maximum Contaminant Level Goals are the

same as the MCL* for both compounds (Table 64).

TABLE «-l

Applicable or Relevant and Appropriate Requirements (ARARs)for Site Contaminants


Delta No. 11-89-185

Federal Ambfeat Water MinacMta A mMtmtQmhty Criteria far Water QmmUtf Criteria

Health k or Aquatic Tttkty ft

UH* Acctptabk AmbientOn-tite MM1 USETA MOC ProtocttM af Ltvtte !•

RAUa MCL/fc /» Water and H»b Flah CMMMIUMI Aqwilk UfcOrtr

1,1 - DkbloroeUMW 9 8W NA MA NA NA NA 0.30

1,1,1 -THchloroeibBae 12 200 200 300 10,400 IfOOfln 130 IM

NA - Not aviilabtea/ Reoomaiended atowable Hmlu lor drinking water contaminant* Minnesota Department of Health, Section of Health Rtek AMeanwat Refetae No. 2, November 1968b/ US. EPA, Office of Drlnkinf Water. Drinkinf Water Standarda, Maximum Contwninam Levdt, Manmum Contaminant Level Ooab and Secondary Standardsc/ from chemical filea In IRIS, an electronic database prepared and maintained by the U.S. EPA. August 1989d/ from the Minnesota Pollution Control Agency, telephone conversation, September 5 and 6, 1989e/ from the Minnesota PoMulion Control Agency, Table B of the •Non-Criteria Source Review Guide,' distributed to members of the Air Tories Technical Advisory Committee,

October 1989.

khv.N21

Remedial Investigation. ReportUnion Scrap Iran and Meul Company1608 Washington Avenue NorthMinneapolis, MinnesotaDelta No. 11-89-185Page 6

The ground water beneath the site is moving at a velocity between 0.48 and 0.16 feet per day. At 0.48feet per day, the ground water beneath the site would take 103 yean to reach the river (1800 feetdowngradient) and 52 yean to reach a wefl half-way between the site and the river. The dimensions ofthe plumes of 1,1-dichloroethane and 1,14-trichloroethane in the ground water and the concentration ofthe compounds within the plume, currently undefined, would determine the duration and level of theexposure for the people using the well.

Fish Concentrations

People who catch and eat fish from the river near the Union Scrap site could potentially be exposed to

contaminants from the site. 1,1-Dichloroethane aad 1,1,1-trichloroethane concentrations in the ground

water will dilute considerably if the plumes discharge to the river. According to a representative of the

Minnesota Department of Natural Resources (DNR), the average flow of the Mississippi River over the

past 55 yean at the Anoka flow station (13 miks downstream from the Coon Rapids Dam and

approximately 9 miles upstream from the Union Scrap site) is 8,019 cubic feet per second. At this flow

rate, concentrations of 1,1-dichloroethane and 1,1,1-trichloroethane entering the river via ground water

discharge would be diluted by several orders of magnitude.

1,1-Dichloroethane and 1,1,1-trichloroethane have been detected in only two monitoring wells onsite. Thisinformation is not sufficient to calculate a volume of ground water that may be contaminated with thesecompounds. However, to give a rough picture of the amount of dilution that b likely to occur in theriver, the following calculations use numben chosen to represent the length, width, and depth of groundwater contaminated with 1,1-dichloroethane and 1,1,1-trichloroethane.

•

Since the two compounds were found in ground water from MW-7 and MW-1S, but were not detectedin water from the side-gradient well MW-3, twice the distance from MW-7 to MW-3 was chosen (160 feet)to represent the width of the plume. The ««•«<•"'•' saturated thickness of the surficial sand and gravelbeneath the site, noted in Chapter 3 (21 feet), was chosen as the depth of the contaminant plume. Asa wont case assumption, the distance from the site to the river was chosen as the length of the plume.In addition, the entire volume of ground water was assumed to be contaminated at the maximumconcentrations of 1,1-dichloroethane and 1,1,1-trichloroethane found in the two wells (9 ug/I and 12 ug/I

respectively).

Remedial Invodtmrion ReportUnioo Scrap Iron and Metal Company1606 Washington Avraue NonbMinneapolis, MinnesotaDelta No. 11-89-185Page?

Contaminants concentrations within the plume were assumed to be unaffected by the effects of adsorption

or degradation, which would tend to decrease contaminant levels. At 0.48 feet per day, the plume would

take 10.3 yean to completely discharge into the river (lySOO feet/0.48 feet/day). Each second, 0.019 ft3

of contaminated ground water would discharge to the river (Equations 6-la and b).

160 ft (wide) x 21 ft (deep) x 0.48 ft/day- 1,613 ft3 /day (Equation 6-la)

1,613 ft3/day / 24 hi/day / 60 min/hr / 60 sec/min• 0.019 ft3/sec (Equation 6-lb)

As noted earlier, the flow of the Mississippi in this area is approximately 8,019 frfysec. Assuming that the

river water upstream from the site does not contain any 1,1-dichloroethane or 1,1,1-trichloroethane, and

that the contaminated ground water mixes completely with only half the flow of the river. Equation 6-2

(USEPA, April, 1988) can be used to estimate the dilated concentrations of 1,1-dichloroethane and 1,1,1-

trichloroethane in the river.

(Qgw x Cgw^ + (Qr x Crt (Equation 6-2)Qgw + Qr/2

4where:

Qgw « ground water flow - 0.019 ft*/MCOr - flow of the river - 8,019 ft3**Cgw •> concentration of contaminant in the ground water

» 9 ug/1 (1,1-dichloroethane) and 12 ug/1 (1,1,1-trichloroethane)Cr - concentration of contaminant in river water • 0 ug/1

Using Equation 6-2, the concentration of 1,1-dichloroethane dilutes to 426 x 10"5 ug/L

CO.Q19 tr/MC « 9 ue/n + r8.019 ft*luc x 0 nt/H0.019 ft*/sec + 8,019/2 ffAec

- 0.171 ua/14,010

- 426 x KT5 ug/1

The concentration of 1,1,1-trichloroethane dilutes to S.69 x 1CT5 ug/L

Remedial Inveatintten ReportUoioQ Scrap Iron and Metal Company1608 Washington Avenue NorthMinaeapolk, MboeaotaDelta No. 11-S9-185PageS

(0.019 ftp/sec x 12 ug/n + (8.019 ftÂec » Q a0019 * lir (

4,010

- 5.69 x ID"5 ug/1

These concentrations are likely to be overestimated for a number of reasons. First, toe actual volume of

contaminated ground water is likely to be smaller than the volume used in this calculation. Secondly, the

actual contaminant concentrations at various locations within the volume may be less than the maximumnumbers used in these equations. Also, actual contaminant concentrations would be likely to decrease as

the plume moves towards the river, due to the effects of adsorption and degradation. Finally, the

discharging ground water was assumed to mix with only half the flow of the river.

Fish and other aquatic organisms in the river near the point of ground water discharge could absorb these

compounds from the water around them. If the contaminants are not excreted, they are said to

bioconcentrate in the organism. Volatile, water-soluble compounds such as 1,1-dichloroethane and 1,1,1-

trichloroethane do not tend to bioconcentrate to a peat extent However, the contaminant concentrationsin Gsh that people could be exposed to can be estimated using Equation 6-3 (USEPA, 1986a).

Cao - (BCF) CvWDw (Equation 6-3)

where: Cao • concentration of the pollutant m aquatic organism at equilibrium (ug/kg)BCF » concentration of pollutant in aquatic organism/concentration in water (bioconcentration

factor)Cw - concentration of pollutant ia water (ug/1)Dw • density of water (kg/I) - 1 kgfl

Although contaminants are likely to dilute to much lower levels (see Equation 6-2), as a worst case

scenario, assume Gsh would be exposed to at much as one tenth of the maximum on-site concentrations

of contaminants as the plume discharges to the river and starts to dilute (0.9 ug/11,1-dichloroethane and


12 ug/1 1,1,1-trichloroethane). Resulting concentrations of 1,1-dkhloroethane and 1,1,1-trichloroethane

in fish tissue would be 1.17 ug/kg and 6.72 ug/kg, respectively, and are presented in Table 6-2. The health

consequences of eating such fish are discussed in Section 6.1.4.

Surface Water Concentrations

People downstream from Minneapolis who use the Mississippi River as a source of drinking water could

also potentially be exposed to contamination from the Union Scrap site. As noted in previous paragraphs,

however, any concentrations of 1,1-dichloroethane and 1,1,1-trichloroethane that discharged to the river

would dilute by several orders of magnitude in the flow of the river. Concentrations at the discharge point

in Minneapolis have been estimated between 4 z 10"* and 6 x 1CT5 ug/1 using Equation 6-2. These

concentrations would be undetectable with current analytical methods which have detection limits of 5 ug/L

Due to the relatively high Henry's constants for 1,1 • dichloroethane and 1,1,1 - trichloroethane (Table

5-1), resulting concentrations would be reduced even further with volatilization of the compounds from

the water to the air. At the Iowa border, if any 1,1-dichloroethane or 1,1,1-Uichloroethane from the

Union Scrap site remained in the river, the concentrations would not be detectable.

4.1.3 Toxldtv Assessment

Chemicals ranging from water, to alcohol, to cyanide are all capable of producing toxic effects in humans,

depending on the quantity to which a person is exposed (the dose) and the duration of the exposure. The

purpose of this portion of the health risk assessment is to characterize the effects of exposure to the given

contaminants of concern at the likely exposure point concentrations described in the previous section.Toxicotogic effects of exposure at higher concentrations will also be described, but will not be the focus

*of this section.

t of Ll.Dlcalofoethsaie

1,1 - Dichloroethane has comparatively little lexicological data. As it has link capacity for causing liver

or kidney damage, and since it suppresses the central nervous system (CNS), it was formerly used as a

human anesthetic (Clayton, 1982).

In humans, direct skin exposure to liquid 1,1-dkhloroethane can cause dermatitis after prolonged contact

The compound is not known as a liver, kidney, or respiratory toxin in humans, although persons with

7.t SUMMARY AND CONCLUSIONS

7.LI Nature and Extent of Contamination

The nature and extent of contamination originating from the Union Scrap site was characterized by twelve

soil borings, one deep well, and six shallow monitoring wells (Figure 7-1 and 7-2). Soil samples were

collected to define the site hydrogeology and to characterize the near surface soils for volatile organics,

semrvolatfle organics, PCBs, and inorganic contamination. The monitoring wells were utilized to estimate

aquifer parameters, determine ground water flow direction, collect ground water samples, and characterize

ground water beneath and adjacent to the site for volatile organics, semrvolatfle organics, PCBs, and

inorganic contamination.

The results of this assessment identified the following compounds as contaminants:

• Tetrachloroethene, trichloroethene and PCBs in soils on site. Tetrachloroethene was found at aconcentration of 6 ug/kg in boring B-5 (the deep sample) and trichloroethene was found at 11ug/kg in boring SB-7 (the shallow sampk)(Figure 7-1). PCB contamination was found at fourlocations in five soil samples, three shallow and one deep. One sample was a duplicate. The PCBconcentrations ranged from 94 to 1,000 ug/kg (Figure 7-1).

• Trichloroethene; 12 • dkUoroethene; 12 • dichloroethane; benzene and xylene were found inground water in the snrficial aquifer but are originating from off-site sources. Trichloroethenewas found in all shallow monitoring wefls. 12 • Dicnloroethene was found in all shallow wellsexcept MW-10. 12 • Dichloroethane was found in upgradient shallow wells MW-14s and MW-10. Benzene, and xylenes were detected only in upgradient well MW-10. No contaminants werefound in MW-14d the deep monitoring well (Figure 7-2).

• 1,1 - Dichloroethane and 1,1,1 - tricUoroethane were found in shallow ground water and appearto be originating from the site. Both compounds were found in low concentrations in on site wellMW-7 and downgradient well MW-15 (Figure 7-2).

No semi-volatiks were anticipated or found in on-dte soils or ground water.

Inorganic anarytes were detected in the she sofls and ground water. However, the ranges of all inorganic

anarytes, except cadmium, were within ranges similar to native soils and the spring water sample

discharging from a Twin Cities water table aquifer. Cadmium was detected in only 3 of 12 samples at

levels slightly above the highest levels found in natural soils.

•f | 5 Ifaf* •nri Tmnnwirf AS?

The fate and transport of six componnds/analytei were assessed for their environmental persistence and

mobility under the conditions at the Union Scrap she. The six compounds/anarytes associated with the

site and the matrix they were detected in are:

a

U

g

SIGHE - Z STOP

CDNVIENIENCE STOREPARKING LDT

B-5

jB-lOB(94) •

OB-ll

B-4(120) s

B-9

OB-3B

(11)

B-80(220) •

(1000) dB-12

O, a

B-l B-6

HYDRANT

16TH AVENUE

POLYCHORINATED BIPHENYLS

• TCTRACHLOROeTHENe

3 TOCHLOROeTHENE

(11) CONCENTRATION IN ug/kg

O SSHALLOW SOIL BORING LOCATION

* SHALLOW SAMPLE

d DEEP SAMPLE

\SCM£ M FtET

FIGURE 7-1SOIL CONTAMINATION


PROJECT NO.

11-89 185DATE

10/^/89

PREPARED BY

BDU/PRDeltaEnvironmentalConwiltanta. Inc.

DCEOfcATCE 260 (320)«

MW-14S

ND10 (12)11 (13) MW-14D

GRASSYAREA

LEGEND

o:o

u

LD

SIGNE - Z STOP


MW-3

DCE 13 (14)TCC 120 (110)

DCA 6 (11)TCE 12 (12)BEN 92 (110)XYL 6 (12)

1.1D 6 (9)DCE 10 (17)TCA 12 (8)TCE 9 (12)

HYDRANT

16TH AVENUE

1.10 ND (5)

to

"DCE-TCA& TCE

105 (7j39 (45)

9 MONITORING WELL LOCATION5.8 CONCENTRATION OF FIRST ROUND (MICROGRAMS/LITER)(11) CONCENTRATION OF SECOND ROUND (MICROGRAMS/LITLR)1.10 1.1 DICHLOROETHANEDCE 1,2 DICHLOROETHENE (TOTAL)DCA 1.2 DICHLOROETHANETCA 1,1,1 TRICHLOROETHANETCE TRICHLOROETHENEBEN BENZENEXYL XYLENES

ND NO VOLATILES DETECTED

TCE 370DCE 14 (21)

NORTH

40

SCALT IN FEET

FIGURE 7-2VOLATILE CONTAMINATION

IN GROUND WATERUNION SCRAP

MINNEAPOLIS, MINNESOTAPROJECT NO.

11-89-185DATE

10/5/89

PREPARED ft

BDO/PRDeltaEnvtTMWTMntolConsultant*. Inc.

Remedial Invrftititloo ReportUnion Scrap Iron and Metal Company1606 Washington Avenue NorthMinneapoiia, MiimmntaDelta No. 11-89-185Page 2

• Trichloroethene, tetrachloroethene, lead and PCBt in soil

• 1,1 • Dichloroethane and 1,1,1 • trichloroethane in ground water.

Trichloroethene and tetrachloroetbene in lofl woald be expected to be mobile and to leach from the soil

However, the limited and relatively low concentration* of these compounds would be attenuated throughrepeated adsorption and leaching. TetrachloroethCM was not detected in ground water and any leaching

of tricUoroethene from soil would not be seen m the ground water given the measured concentrations

already present

Lead was assessed because of the high concentrations in the surface sofl prior to the EPA Removal

Actions. Lead has remained immobile in the near surface soft. Lead concentrations in soil below the

excavation limit of the EPA Removal Actions are within the lead concentrations found in natural soils.

Two volatile organic compounds, 1,1 • dichloroethane and 1,1,1 • trichloroethane, were detected in both

on-site well MW-7 and downgradient well MW-15 aad appear to originate from the Union Scrap site.

However, neither compound was detected in the soil samples. Both 1,1 • dichloroethane and 1,1,1 -

trichloroethane, are soluble in water and are expected to migrate with the ground water. The low

concentrations in the water are expected to decrease through dispersion, dilution, and biodegradation in

the aquifer. The expected travel time to the discharge point, the Mississippi River, is approximately 10

years. This is based on the conservative asramptiM of ground water flow velocity of 0.48 feet per day.

No detectable levels of these compounds that are attributable to the site, are expected to discharge to the

Mississippi River in the future.

The risk assessment was divided into a public health risk assessment and an environmental assessment

In the public health risk assessment, two orgaak compounds were assessed for their impact on three

receptor populations. The organic compounds am 14 • dkhloroethane and 1,1,1 • trichloroethane. The

receptor populations are an unidentified well utffizug the shallow ground water as drinking water, people

who catch and consume fish from the Mississippi River at or downstream from the Plymouth Avenue

bridge (the projected ground water discharge point), and the population utilizing the Mississippi River as

Remedial Invotintioo ReportUnioo Scrip Iron end MeuU Coaftof1608 Wathmftoo Avenue NorthMinneapolis, MkunotaDelta No. 11-49-185Page 3

a drinking water supply downstream from the Plymouth Avenue bridge (intake at the Minnesota • Iowaborder).

The environmental assessment evaluated the impact of 1,1 - dichloroethane and 1,1,1 - trichloroethane on

aquatic organisms.

Concentrations of 1,1- dichloroethane and 1,1,1- trichloroethane at the unidentified ground water receptor

populations were estimated, using worst case-assumptions (Le. the site concentrations), of 9 ug/1 and 12

ng/l, respectively. Concentrations of 1,1- dichloroethane and 1,1,1- trichloroethane are well below federal

Maximum Contaminant Levels and state Recommended Allowable Limits and do not pose elevated health

risks.

Concentrations of 1,1- dichloroethane and 1,14- trichloroethane in fish were also estimated, assuming

that maximum on-site concentrations discharged to the river and diluted to only one tenth of their original

concentrations. Assuming as a worst-case that persons catching and eating fish would consume 30 grams

of fish per day, even though fish advisories have been issued for this portion of the river, human exposure

was still well below levels of concern for health risks.

The nearest known, downstream drinking water on the Mississippi is in Iowa, at least 100 miles south ofMinneapolis. Concentrations of 1,1- dichloroethane, and 1,1,1- trichloroethane from the site at the Iowa

border are estimated to be several orders of ""ir'*1*1* below the detection limits for these compounds.

This estimation it due to several factors ii^hMMl>| the following: the low levels of l,l-dichk>roethane and

U.l-trichloroethane currently on site; the estimated 1800 feet between the site and the projected ground

water discharge point; the large flow of and potential for dilution in the Mississippi River, and the

potential for volatilization of the contaminants Iron the river water. Therefore, human health risks are

not likely to be elevated doe to ingestion of contaminants from the site in surface water.

The environmental assessment compared estimated surface water concentrations of l,l-dkhk>roethane and

1,1,1- trichloroethane to available water quality criteria for aquatic toxkity. No criteria were available for

1,1- dichloroethane. However, the projected 1,1,1- trichloroethane concentrations (12 ug/1) in the river

and maximum concentrations of this contaminant on site (12 ug/1) are well below the state of Minnesota's

Remedial laveitiiatjoo ReportUnioo Scrip Iron and Metal Company1606 Washington AMDIM NorthMinoeapolit, MinoaotaDelta No. 11-89-18SPage 4

aquatic toxkity criteria of 138 ug/1 (Table 6.1). Therefore, aquatk organisms are not likely to be

negatively impacted due to the presence of these contaminants from the soil in the surface water.

7.2 ConcinikMis

7.2.1 Data Limitations and RecomnmH**Honi for Future Work

The site investigation, including sampling of sou* and ground water was thorough. However, detailed

review of all data developed indicates that the detection limits for semi-volatiles were above Minnesota

Department of Health (MDH) recommended allowable limits (RALs); most importantly for the

polynuclear aromatic hydrocarbons (PAHs). The detection limits should have been low enough, in the

part per trillion level, so sample data could be compared to RALs.

There was also limited data available concerning the new Gil material brought in by EPA during the

Emergency Removal Actions of lead contaminated soils. Additionally, there is limited soils chemistry data

between the deep (approximately 10 to 12 feel deep) soil samples and the ground water table

(approximately 30 feet deep).

There was however, sufficient data collected to evaluate conditions at the site and make appropriate

decisions and recommendations related to furore activities at the Union Scrap site.

The risk assessment showed clearly that there are no potentially affected human populations and that the

environmental risk is below criteria for the contaminants identified as originating from the Union Scrap

site. Therefore, as relates to the Union Scrap site, at 1608 Washington Avenue North, no further work

is necessary.

The two separate ground water problems originating from off-site sources identified during the RI will

be followed up by the MPCA through normal administrative processes, Le., reporting of the investigation

findings to the PA/SI program (the TCE plane) and the Tanks program (the benzene and xylene

occurrence). These referrals will allow these programs to deal with these problems consistent with their

program's priorities.

tiintkUnion Scnp Iron iad Metal Company1606 Wathinfioa Avenue NorthMinneapotit, MtaneeotaDelta No. 11-39-185

7.2.2 Recommended Remedial Action

Potential Alternative Remedial Actions (RAs) were identified for the site in Chapter 1 of the RI/FS

Support Document The various RAs discussed were developed based upon the nine evaluation criteria

which would be used in the Feasibility Study to determine acceptance:

• Protection of human health and the environment

• Compliance with ARARs.

• Long term effectiveness.

• Reduction of toricity, mobility, and volume.

• Soon term effectiveness.

• ImplementabOity.

Costs.

• Agency acceptance.

• Community acceptance.

Potential ARARs were identified in Section 1A6 of the Support Document and a summary for

contaminants of concern at the Union Scrap site it presented in Table 6-L

Section 1.7 of the Support Document listed several potential alternative response actions, both for soil and

ground water. These objectives and alternatives for sofls and ground water are presented below. These

alternatives are discussed taking the RI results into consideration and conclusions are presented for soil

and ground water alternatives.

SOILS

Soil remedial action objectives are to prevent leaching of contaminants from soil to ground water and

to prevent human contact with contaminants in sofl.

The following potential alternatives were presented a the Support Document to meet these objectives:

• No action.

• Excavation and off-site disposal by landfllHiig.• Excavation and off-site disposal of soils by incineration.

iratô RUnion Scrap Iron tod Metal Compujr1606 Washington Avenue NorthMmneapotit, MmnetouDelta No. 1149-185Page 6

• Excavation and on-site disposal of soils by incineration.

• Excavation and on-site disposal of soOs in a vault

• Excavation, soil scrubbing, and on-«ite treatmenL

• Capping the site.

• In-situ vitrification.

• Sou" flushing.

The RI results showed only three contaminants in soils; tetrachloroethene, trichloroetbene, and PCBs.

These contaminants were found in low part per billion levels in only a few locations. There is not a

significant source or amount of contaminated soils at the Union Scrap site. Consequently, the excavation

alternatives are not feasible as there is no significant quantity of sofl to remove. Capping is not a

reasonable alternative because, according to the risk assessment, the limited extent and amounts of

contamination are not expected to be a problem aider present conditions. In situ vitrification would be

unnecessary and very expensive. In place sofl flashing would only enhance leaching of contaminants to

ground water. Therefore, the only practical alternative for residual soil contamination at the Union Scrap

site is no action.

GROUND WATER

If ground water contamination poses elevated health risks, then the ground water remedial action objective

fa to reduce risk to the range of 10*4 to 10*7 for maximum lifetime risk.

The following preliminary alternatives were presented in the Support Document to meet this objective:

*

• No action

• Containment

• Treatment

Ground water extraction and on-tite treatment of metalsGround water extraction and on-tite treatment of PCBsGround water extraction and on-site treatment of metab and PCBsGround water extraction with discharge to sanitary sewerIn-situ treatment

Unioa Scrap Iron and Metal Company1608 WtthiDftoa Avenue NorthMtaoeapofe, MbaewuDelta Na 11-89-185Page 7

The RI results indicated only two contaminants in ground water that may be originating at the Union

Scrap site. These are 1,1 • dichloroethaoe amd 1,1,1 • trichloroethane. All other ground water

contaminants that were identified are attributable to other sources.

The risk assessment in Chapter 6 shows that concentrations of these contaminants at the site are already

below any applicable or relevant and appropriate requirements (ARARs). Additionally, they were foundin only two shallow monitoring wells, MW-7 and MW-15.

Consequently, containment or treatment of the ground water contaminated by past Union Scrap operations

is not justifiable primarily because this contamfnattott does not pose any additional significant health or

environmental risks. Therefore, the only practical alternative for ground water contamination originating

from the Union Scrap site is no action.

Based on the discussion above and the results of the RI, "no action* alternatives are recommended for

soils and ground water at this site. Additionally, because of the recommendation of no further work, a

feasibility report b not appropriate.

The recommendations contained in this report represent our professional opinions. These opinions are

based on currently available information and are arrived at in accordance with currently accepted

hydrogeologic and engineering practices at this time and location. Other than this, no warranty is implied

or intended.

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Aerospace Medical Division (AMD), 1985. The Installation Restoration Program Toxicology Guide, Vol

Balaban, N.H.. 1989 editor, Geologic Atlas, Henaepin County, Minnesota, Minnesota Geological SurveyCounty Atlas Series, Atlas C-4.

Battelle Columbus Labs, Multimedia Levels: Methyfchlorofonn, P, 3-1 to 3-6, EPA-560/6-77-030, 1977.

BoOcess R., Edelson E, 1981. Chemical Principles. Harpor and Row

Bouwer EJ., McCarty P.L, Applied Environmental Microbiology, 45:1286-94,1983.

Braun Environmental Laboratories, 1986, Sofl Borings and Analysis Union Scrap Yard, Minneapolis,Minnesota, October 1986.

Callahan MA., et al. Water-related Environmental Fate of 129 Priority Pollutants, Vol II, P. 45-1 to 45-12, EPA-44(V4-79-029B, 1979.

Christiansen, V.O., J.A. Dahlberg, and H.F. Anderson, 1972. On the nonsensitized photo-oxidation of1,1,1 • trichloroethane vapor in air. Acta. Chetn. Scandinavian Series A 263319-3324.

Clayton G.D., Clayton F.E.; Patty's Industrial Hvriene and Toxicology. 3rd Revised Edition. John Wiley& Sons, New York, 1981

Driscoll, F.G.. 1986, Ground Water and Wells. Johnson Division, SL Paul, MN, 2nd edition.

Eisenreich SJ., et al; Environmental Science and Technology 15:30-8 (1981).

Freeze, R-A. and JA. Cherry, 1979, Ground Water. Prentice-Hall, Inc., Englewood Cliffs, NJ.

Hem, J.D., Study and Interpretation of Chemical Characteristics of Natural Water, 1985, U.S. GeologicalSurvey Water • Supply Paper 2254.

Horn. MJL, 1963, Ground Water Use Treads fat the Twin Cities Metropolitan Area, Minnesota, 1880 •1980, United States Geological Survey Water Resources Investigations Report 83-4033.

*

HSDB, Hazardous Substances Data Bank, a fife ta Toxnet, a component of the National Library ofMedicine's MEDLARS system, August 22-29,1989.

International Technology Corporation, 1988, Preliminary Draft RI/FS Work Plan, Union ScrapInvestigation, Minneapolis, Minnesota, March 1988

IRIS (Integrated Risk Information System), An electronic database prepared and maintained by the US.Environmental Protection Agency, flie OB PCBs, August 22,1989.

IRIS, USEPA-maintatned, electronic database ffle on 1,1,1 - trichloroethane modified in June 1989.

Jirsa, M.A., B.M. Olsen, B.A, Bloomgren, 1966, Bedrock Geologic Map of the Seven County Twin CitiesMetropolitan Area, Minnesota, Minnesota Geological Survey, Miscellaneous Map Series, M-55.

Kanfvetsk, R., 1989, Bedrock Hydrogeology, Plate & in Geologic Atlas, Hennepin County, Minnesota,Minnesota Geological Survey County Atlas Series, Atlas C-4, N.H., Balaban, ed.

Kuratsune, M et al; Environmental Health Perspectives, 1: 119-28, 1972.

Letter, A., et al; Environmental Transport and Transformation of For/chlorinated Biphenyb p. 5-1 to5-18 (1983) EPA-560/5-83-025, NTIS PB84-142579.

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Metropolitan Waste Control Commission, 1989, 1987 River Quality Data Report, Quality ControlDepartment Report No. QC-87-154.

Meyer, G.N., 1985, Quaternary Geologic Map of the Minneapolis-SL Paul Urban Area, Minnesota,Minnesota Geological Survey Miscellaneous Map Series, M-54.

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Parsons, R, P.R, Wood and J. DeMarco, 1984, Transformation of tetrachloroethene an trichloroethanein microcosms and ground water, JAWWA, 26 (2): 56t

Pearson, C.R. and G. McConnell, Proc. Roy. Soc. London B 189305-32,1975.

Roy F. Weston, Inc. 1985, Site Assessment for Union Scrap Iron and Metal Company, Minneapolis,Minnesota, May 1985.

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