Record of DecisionGround Water Treatment Operable Unit

Site Name and Location; Stauffer Chemical/LeMoyne - Axis, AlabamaStauffer Chemical/Cold Creek - Bucks, Alabama

Statement of Basis and Purpose!

This decision document presents the selected remedial action for the StaufferChemical LeMoyne and Cold Creek Sites, in Mobile County, Alabama, developedin accordance with the Comprehensive Environmental Response, Compensation andLiability Act of 1980 (CERCLA), as amended by the Superfund Amendment andReauthorization Act of 1986 (SARA), and to the extent practicable, theNational Contingency Plan (40 CFR 300). The decision is based on theadministrative record for the sites. The attached index identifies the itemsthat comprise the administrative record upon which the selection of theremedial action is based.

The State of Alabama has concurred on the selected remedy.

Site Assessment ;

Actual or threatened releases of hazardous substances from this site, if notaddressed by implementing the response action selected in this Record ofDecision (ROD), may present an imminent and substantial endangerment topublic health, welfare, or the environment.

Description of the Selected Remedy

This initial ground water operable unit is the first of three planned for theStauffer sites. It addresses a principal threat at the sites by controllingthe migration of contaminants present in the surficial aquifer. The operableunit is fully consistent with all planned future site activities. Futuresite activities include treatability studies or piloting of treatmenttechnologies for the source control and swamp operable units, which willcomprise the overall site remedy.

The major osjpponents of the selected remedy are as follows:* Modify%Ki«ting ground water intercept and treatment system; install

additional monitoring (Detection Monitoring) and extraction wells' Continue extracting ground water from the surficial aquifer via existing

and additional intercept wells' Monitor ground water movement at the site to determine the adequacy of

the remedial action' Conduct treatability studies as appropriate for source treatment of RCRA

Solid Waste Management Units (SWMUs) and CERCLA disposal sites* Decommission wells no longer needed for monitoring

5 9 002

Declaration

The selected remedy is protective of human health and the environment,attains Federal and State requirements that are applicable or relevant andappropriate to the remedial acc.or., and is cost-effective. The remedysatisfies the statutory preference for remedies that employ treatment thatreduces toxicity, mobility, or volume as • principal element and utilizesperrr.a.-.er.t solutions and alternative treatment (or resource recovery)technologies to the maximum extent practicable.

Because this remedy will result in hazardous substances remaining on-siteabove health-based levels, a review will be conducted within five years aftercommencement of remedial action to ensure that the remedy continues toprovide adequate protection of human health and the environment.

(Date) Greer C. TidwellRegional Administrator

5 9 003

Record of Decision

Summary of Remedial Alternative Selection

Stauffer Chemical - LeMoyne and Cold Creek Sites

Axis and Bucks, Mobile County, Alabama

Prepared by:U.S. Environmental Protection Agency

Region IVAtlanta, Georgia

5 9 004TABLE OF CONTENTS

I.0 Site Location and Description.......................................... 1

2.0 S ite History........................................................... 12.1 LeMoyne........................................................... 12.2 Cold Creek........................................................ 42.3 Enforcement History............................................... 4

3.0 Community Relations History............................................ 5

4.0 Scope of Remedial Action...............................................6

5.0 Site Characteristics ................................................... 6

6.0 Summary of Site Risks................................................. 126.1 Exposure Assessment Summary...................................... 126.2 Toxicity Assessment.............................................. 146.3 Risk Characterization............................................146.4 Environmental Risk...............................................15

7.0 Documentation of Significant Changes..................................15

8.0 Description of Alternatives...........................................158.1 Alternative 1 - No Action........................................ 158.2 Alternative 2 - Existing Ground Hater Intercept and Treatment

System with Surface Hater Discharge.............. 168.3 Alternative 3 - Modified Ground Hater Intercept and Treatment

System with Surface Hater Discharge.............. 168.4 Alternative 4 - Existing Ground Hater Intercept and Treatment

System with Surface Hater Discharge and In-situVapor Extraction................................. 19

9.0 Summary of Comparative Analysis of Alternatives....................... 199.1 Protectiveneaa of Human Health and the Environment............... 209.2 Compliance with Applicable or Relevant and Appropriate

Requirements (ARARS)............................................ .209.3 Reduction of Toxicity, Mobility, or Volume....................... 219.4 Short-term Effectiveness......................................... 219.5 Long-term Effectiveness..........................................219.6 laplementabilty..................................................219.7 Opt.............................................................219.8 0£evte and Community Acceptance................................... 22

10.0 The Selected Remedy...................................................22

II.0 Statutory Determinations..............................................2311.1 Protection of Human Health and the Environment..................2311.2 Attainment of Applicable or Relevant and Appropriate

Requirements................................................... .2311.3 Cost-Effectiveness.............................................. 2411.4 Utilization of Permament Solutions and Alternative Treatment or

Resource Recovery Technologies to the Maximum ExtentPracticable.....................................................24

11.5 Preference for Treatment as a Principal Element................. 24

59 005-LIST OF FIGURES

Figure 1.1 - Sit* Location Map..............................................2

Figure 2.1- Site Configuration.............................................3

Tigure 5.1 - Flood Plain Map................................................7

Figure 5.2 - Source Well Sample Locations................................... 9

Figure 5.3 - Area Well Sample Locations.................................... 10

Figure 8.1 - Site Area Well Locations...................................... 17

LIST OF TABLES

Table 5.1 - Results of Ground Water Sampling...............................11

Table 6.1 - Ground Water Contaminants of Concern........................... 13

Table 8.1 - Ground Water Cleanup Goals..................................... 18

LIST OF APPENDICES

Appendix A - Responsiveness Summary

Appendix B - State Concurrence Memorandum

5 9 006Summary of Remedial Alternative Selection

Stauffer Chemical/LeMovne SiteGround Water Operable Unit

1.0 SITE LOCATION AKD DESCRIPTION

The Stauffer Chemical LeMoyne and Cold Creek Sites (See Figure 1.1) arelocated approximately 20 miles north of Mobile, Alabama on U.S. Route 43.The Stauffer complex is bounded by Hoerchst Celanese to the north, CourtauldsNorth America (CNA), another chemical company, to the south, the Mobile Riverto the east, and Route 43 to the west. M&T Chemicals is located immediatelyto the west of Route 43. The area is predominantly industrial, with a fewsmall rural residential communities within a few miles of the site. TheLeMoyne facility manufactures multi-product organic and inorganic chemicals,including carbon disulfide, carbon tetrachloride, sulfuric acid, chlorine,and crystex (a sulfur compound).

Surface elevations range from 10 to 45 feet above MSL. An unnamed streamflows north across the property and then through the Cold Creek Swamp, whichdischarges into the Mobile River. Surface-water drainage is either towardthe swamp or the river and is governed by a drainage divide between the two.The Mobile River flows southward toward the Gulf of Mexico.

2.0 SITE HISTORY

2.1 LeMovneThe LeMoyne plant was previously owned by the Stauffer Chemical Company,which began operations in 1953. In 1987, the facility was purchased by AkzoChemie America, Inc., now called Akzo Chemicals, Inc. From 1965 to 1974,while still operated by Stauffer, waste from the plant was placed in anunlined landfill (Figure 2.1) located approximately one mile east of the mainplant. The waste included 11,000 to 12,000 tons of brine muds in addition toplant refuse, used samples, and absorption oil. Under the direction of theAlabama Water Improvement Commission (AWIC), the landfill was closed in 1975with an impermeable membrane cap and side-wall liner.

Wastewaters from the LeMoyne plant processes were held in ponds, some ofwhich discharged to the Cold Creek Swamp. All of these ponds except for oneare clay-lilted and have been closed under the direction of AWIC. Severalmembrane-lined ponds, which are currently active, were installed during the1970's to replace those mentioned above. One of these is regulated by aResource Conservation and Recovery Act (RCRA) permit.

From 1965 to 1979, a small portion of land on the western end of the LeMoynesite was leased by Stauffer to the Halby Chemical Company (HCC), whichmanufactured dye chemicals including sodium hydrosulfide. Witco, Inc.purchased the HCC facility in 1974, and continued to operate the plant until1979. Although little is known of this operation, waste products andeffluents were reportedly discharged to the Cold Creek Swamp and held in anon-site pond, which has since been closed and filled.

5 9 007

COLD CREEK & LEMOYNE SITE_ MOBILE COUNTY. ALABAMA -|

PLANT/--LI

* i •:URTAULDS Of V.,

NORTH AMERICA .;.-

CAMP DRESSER & McKEE INC.SITE LOCATION MAP

STAUFFER CHEMICAL COMPANYMOBILE COUNTY, ALABAMA _____

FIGURE NO.

1.1

Col<Jd«*kSw*mp

N Fliawatar Pond —

Appionlmal* ',c«l«

LaMovn* Plant Oiound W»l«rul

LaMoyn* Landfill

- LaMoyn* AcidPlant WWT Pond

tuplo nation:

N - rioitliS c SouiliWWr - W«ll«w*l*r IronlmanlCli: - Cflrhon

- Orlion Dliulluln

OM CSj/CTCWWT Pond

Nola: Location* aia •ppronlmil*; ••• Flgur* 4-1 lor a moi« prnclt* location of ihn i»op«riy bounilMrltt(Mo-lt»l«rt AUnr ( HM till',I

r i< |uro 2.1 Cold Cre»;k/l,«'Moyiu; T. i I • ( ' « > n f i qiu .1 1 i on

5 9 009--4-

2.2 Cold Creek

The Cold Creek plant began operating in 1966 under the ownership of theStauffer Chemical Company and ia currently owned by ICI Americaa, Inc. Until1974, an unknown.amount of sludges and solid wastes containing a variety ofherbicides and pesticides were placed in two waste disposal sites, referredtc as the Cold Creek North and South Landfills. Both were closed in 1974with geomembrane caps and side-wall liners. One clay-lined lagoon was usedf:r neutralization of wastewater until 1975. It was closed in 1978. A newmembrane-lined pond was constructed to replace it and is currently in use.

2.3 Enforcement History

The aforementioned disposal practices led to ground water contamination.This was recognized by Stauffer and the Alabama Department of EnvironmentalManagement (ADEM) in the early 1970's when contaminants were detected in bothon-site and off-site wells. Several improvements and waste-handlingmodifications were made including the construction of lined wastewater pondsand the closure of some of the old unlined ponds. In 1973, Staufferinstalled twenty-one ground water monitoring wells. By 1977, the waterquality had deteriorated substantially and seven observation wells wereplaced at the southern property line of the LeMoyne facility. Using theresults from a hydrogeological investigation performed by the owner/operator',three interceptor wells accompanied by an air stripper were installed on theLeMoyne property in late 1980. The system was approved by the Alabama WaterImprovement Commission (AWIC) which is now the Alabama Department ofEnvironmental Management (ADEM).

An assessment of the site was conducted in 1982 by the Alabama Department ofPublic Health (ADPH) in response to submissions made by Stauffer to the HouseCommittee on Interstate Commerce (the Kckhardt Survey). At the advice ofADPH, additional monitoring wells were installed around the LeMoyneLandfill. Data from these wells formed the basis for the EnvironmentalProtection Agency (EPA) placing the site on the National Priorities List(NPL), which ranks hazardous disposal sites under provisions of theComprehensive Environmental Response, Compensation and Liability Act of 1980(CERCLA), commonly known as "Superfund". The Stauffer Sites were placed onthe NPL in September, 1983. LeMoyne is ranked number 467 and Cold Creek isnumber 221,"

In November 1984, EPA Region IV sent a general notice letter to StaufferChemical Company notifying them of potential liability for contamination atthe Stauffer Chemical Site. Camp, Dresser and McKee, Inc. (COM), undercontract with the EPA, performed preliminary sampling in May 1985 to assistin preparing a work plan for the Remedial Investigation/Feasibility Study(RI/FS). The Stauffer Chemical Company agreed to conduct the RI/FS under aconsent agreement with EPA, and the present owners, Akzo and ICI, completedthe RI in May, 1988. A draft FS report was submitted by the presentowner/operator in July, 1988. EPA required modifications to the FS report incomment letters sent in November, 1988 and January, 1989. A revised reportwas submitted in June, 1989. This report was reviewed by EPA and waspartially disapproved.

5 9 010--5-

The Stauffer Chemical Company/LeMoyne Plant was issued a RCRA permit onOctober 9, 1986, which became effective November 9, 1986. The permit was forthe operation of two hazardous waste surface impoundments and a hazardouswaste storage tank.

Unit Hazardous Wyste CodaBrine Mud Slurry Tank K071Chlorine Plant Surge Pond D009, K071New Brine Mud Pond K071Old Brine Mud Pond K071

The Chlorine Plant Surge Pond was certified clean-closed in September, 1988according to the approved closure plan. The Old Brine Mud Pond has beendelisted.

An additional provision was included in this permit as a result of the 1984Hazardous and Solid Haste Amendments to RCRA. This is the requirement of 40CFR, Section 264.101, which addresses prior or continuing releases at solidwaste management units. The requirement has been satisfied by adoption ofthe Remedial Investigation/Feasibility Study work plan, developed underCERCLA, into the permit. The permit will be modified once the Record ofDecision has been issued.

3.0 COMMUNITY RELATIONS HISTORY

Community interest for the Stauffer Chemical site has been limited. Severalnews articles concerning the site have been printed in the Mobile PressRegister and the Montgomery Advertiser. A Community Relations Plan wascompleted in September, 1985. In May 1986, the EPA printed and distributed afact sheet describing the site history and findings of investigationsconducted at the site. A fact sheet announcing EPA's Proposed Plan was issuedon July 11, 1989.

A related issue of concern to the people of Mobile County, Alabama is transportand disposal of wastes within their county. This concern arose as a result ofa proposal to begin hazardous waste incineration in the Gulf of Mexico via theMobile port.

On July 13, 1989, the administrative record which contains documents related toremedy selection at the site, including the Remedial Investigation/FeasibilityStudy, an4 Deposed Plan, was made available to the public at the Region IV EPAoffices in fttlanta, Georgia and the Toulminville Branch Library in Mobile,Alabama. Thi« began a 30-day public comment period to solicit public opinionon the proposed remedial action at Stauffer Chemical. A public meeting wasconducted on July 27, 1989, at which EPA presented the RI/FS report andProposed Plan and answered citizens' questions. The Mobile CountyCommissioners and County Administrator were briefed prior to the meeting.Public comments on the selected remedy and EPA's responses are included in theResponsiveness Summary section of this document. This decision documentpresents the selected remedial action for the Stauffer Chemical LeMoyne andCold Creek sites in Mobile County, Alabama, chosen in accordance with CERCLA,as amended by SARA, and to the extent practicable, the NCP. The decision forthese sites is based on the administrative record file.

59 Q

-6-

4.0 SCOPE flg REMEDIAL ACTION

OU 1; Ground Water and Contaminant SourcesT;._s addresses the first Record of Decision (ROD) of several planned activitiesat the site. It-deals with the existing ground water problem and treatabilitystudies on the sources of contamination.

The response actions presented in this ROD are being implemented to protectpublic health and the environment by controlling the migration of contaminatedground water in the surficial aquifer, which is a principal source of water forindustrial and domestic users located in the Mobile River Valley. The US EPAhas determined that off-site migration of the contaminated ground water is oneof the principal threats at these sites.

The response actions are consistent with the NCP (40 CFR 300.68). Theseactions are also consistent with plans for future remedial work to be conductedat the LeMoyne and Cold Creek sites.

Further investigation and treatability studies are necessary before the EPA canmake decisions concerning treatment of source materials.

OU 2; Source UnitsOU 3; Cold Creek Swamp ;The remedial action for the source units and the Cold Creek Swamp will beaddressed in a subsequent RODs.

5.0 SITE CHARACTERISTICS

The Stauffer sites are located in the southern Pine Hills Section of the EastGulf Coastal Plain physiographic province. The site is underlain byPleistocene to Holocene alluvial deposits consisting of interbedded clays,sands, and gravels. These deposits range in thickness from 130 feet to 60 feetat the edge of the Mobile River and form the surficial Miocene aquifer which isthe principal source of water in the Mobile River Valley. The upper 80 feethas low to moderate permeability with the lowermost sands containing the mosthighly permeable material. Wells in this aquifer typically yield 470 to 816gallons per minute (gptn) with specific capacities of 6 to 73 gpm per foot ofdraw down. A dense blue-grey estuarine clay forms the base of the aquifer.

Surface dcsdJiage for the Cold Creek site and the western portion of the LeMoyneproperty l toward an unnamed stream which flows northward toward the ColdCreek Swaa *. The eastern portion of LeMoyne is adjacent to and drains towardthe Mobile River. Flooding potential at the site is considered to be minimal.One-hundred-year to five-hundred-year flood zones are shown in Figure S.I.

Prior to industrialization, the direction of ground water flow was eastwardtoward the Mobile River and its depth ranged from 0 to 20 feet below groundsurface. Installation of wells on the adjacent Courtaulds property hasresulted in a lowering of the water table to between 25 and 75 feet belowground surface. Furthermore, direction of ground water flow has been changedto southwest on the western portion of the site and to the southeast on theeastern portion. Most of the industries and local communities in the area

-7-

5 9 012

Not«: Flood Information from Rood Inauranea MataMip. Community »anal No. 016008 0125 F ft01SOF,M«riaao:i-3-«S. SCALE

Topographic Informauon Takan from USCS TopoMap. 1M2.

013 "-8-

obtain water supplied from the surficial aquifer.

As shown in Figure 1, the LeMoyne facility has two drinking water wells (LM-7and LM-10) which provide water for 230 employees, and the Cold Creek plant hasone drinking water well (CC-12) with one backup (CC-11), serving 250employees. The CNA plant to the south has one primary drinking water well(CNA-16) and a backup well (CNA-4), serving 750 employees. M&T Chemicals, onthe west side of Route 43, uses well water for their 200 employees. All ofthese wells draw water from the surficial aquifer.

The Remedial Investigation, conducted by the owner/operator under a consentagreement with the EPA, was divided into two major subtasks - source and areacharacterization. Source characterization was performed by soil samplingaround the landfills and ponds, and sampling of pond liquids. Ground watersampling of two newly installed and thirteen existing monitoring wells was alsoconducted. All of these wells were analyzed for location-specific compounds,and three of them were also analyzed for priority pollutants. Areacharacterization involved sampling 36 site area wells for location-specificcompounds. Seven of the 36 wells were also analyzed for priority pollutants.In addition, two surface water samples and two soil samples were collectedoff-site to determine background concentration of the contaminants of concern.Well locations are shown in Figures 5.2 and 5.3, and results of the samplingand analysis are summarized in Table 5.1. >

As a result of the above analysis, ten areas were identified as possiblyneeding remediation. These included five inactive ponds, three landfills, theCold Creek Swamp, and the ground water. The ponds and landfills are classifiedas Solid Waste Management Units (SWMUs) under RCRA regulations. EPA hasgrouped these units into nine Solid Waste Management Unit Areas. They are asfollows:

SWMU Area II - Cold Creek LeCreek Wastewater Treatment PondCold Creek Old Neutralization PondCold Creek South Landfill

SWMU Area 12 - Old Carbon Disulfide Wastewater Treatment PondOld Carbon Tetrachloride Plant Wastewater Treatment Pond

SWMU Ar«* 13 - Cold Creek North Landfill

SWMU AMa 14 - Old Brine Mud Pond

SWMU Area fS - New Carbon Tetrachloride Plant Wastewater Treatment Pond

SWMU Area 16 - LeMoyne LeCreek Wastewater Treatment Pond

SWMU Area 17 - Old Chlorine Plant Wastewater Treatment Pond

SWMU Area 18 - LeMoyne Landfill

SWMU Area 19 - Halby Pond

(Modiliad Altar CDM. 1986)

300

o eooFtApproximate Scala

old Craah Plant

aMoyna Plant

Explanation:• Wall Location (apprmlmata)

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CD

Figure r>.2 Source Well Sample Locations

5 9 0 1 5

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5 9 017--12-

6.Q SUMMAKY OF SITE RISKS

The following discussion provides an overview of the baseline public health andenvironmental risk evaluation for the Stauffer LeMoyne and Cold Creek Sites.It is based on t-he report "Endangerment Assessment Report Cold Creek/LeMoyneSite, Mobile County, Alabama", prepared by the owner/operator. The baselineevaluation helps determine if a remedial action is necessary at the sites. Itrepresents an evaluation of the "no-action alternative", in that it identifiesthe risk present if no remedial action is taken. The baseline assessment alsoprovides the framework for developing the preliminary remediation goals for theStauffer sites. Field observations and analytical data as presented in theRemedial Investigation report provided the basis for the risk evaluation.There are four media of concern at the Stauffer Site. The RemedialInvestigation revealed contamination of the soils, pond sludges, swampsediments, and ground water.

Based on the frequency of detection, the concentrations detected, and thetoxicological properties of the contaminants which were detected, the followingcompounds were selected as indicator compounds for this site: mercury, carbontetrachloride, carbon disulfide, cyanide, thiocyanate, and six thiocarbamates,EPTC, butylate, vernolate, pebulate, molinate, and cycloate. Of thesecompounds, all but mercury and cyanide were detected in the ground water. Atable showing the concentrations of these substances in ground water and theassociated risk can be found at Table 6.1.

The ground water data used to calculate the baseline risk assessment werecollected from wells downgradient of the intercept well system. The baselinerisk assessment should reflect the conditions for the no action alternative,which would exist if the intercept and treatment system were shut down. Sincethe risk levels in the RI do not represent these baseline risk conditions atthe sites, risk levels have been calculated for the ROD which represent theworst case and average case scenarios.

6.1 Exposure Assessment Summary

The exposure pathway for the ground water operable unit is ingestion ofcontaminated water from wells drilled into the surficial aquifer. Average andworst-case risk estimates were developed for a 70 kg adult worker. Theexposure point concentration for the worst case scenario is based on theconsumption,,J>f ground water containing the maximum contaminant concentration.The averagi£~«flcposure point concentration is based on the consumption of groundwater containing the average concentration of contaminants in the ground waterplume (i.e. wells O-29, O-31, O-39, O-41, O-45). Both estimates assumed theworker would drink two liters of water a day for 30 years and used anabsorption factor of one (1.0) for organics and inorganics.

The number of workers served by industrial drinking water supply wells within atwo-mile radius of the sites is 1585. There are 21 residential wells withinthat radius.

5 9 018 -13-

TABLE 6.1- GROUND WATER CONTAMINANTS OF CONCERN

Maximum Mean RiskCPF Concentration Concentration Level

Carcinogens (ma/ka-day—} (mo/1^ (mg/H Max./Mean

CarbonTetrachloride 1.3x10-1

4.6xlO~*/298 68.8 1.07x10-1

Risk Level is for a 30 year exposure period

MaximumRfD , Concentration

Mean HazardConcentration Quotient(ma/11 Max./Mean

Carbon Bisulfide

CarbonTetrachloride

Thiocyanates

Butylate

Cycloate

EPTC

Molinate

Pebulate

Vernolate ;

1X10"1

7xlO~4

NE

5xlO~2

NE

3xlO"2

2xlO~3

NE

IxlO'3

55.6

298.0

6.0

0.014

0.007

1.2

0.231

0.002

0.009

15.6

ND

0.004

0.003

0.006

0.010

0.001

0.008

155/4.4«

11920/2752

7.84xlO"3/2.2 xlO'3

l.l/5.6xlO~3

3.2/1.4X10'1

2.5X10'1/ ,2.2X10'1

NE - None established

ND - Not detected in the wells used for determining the averageexposure point concentration.

B 9 010--14-

6.2 Toxicitv Assessment

Chemicals exhibiting non-carcinogenic effects are assessed using risk referencedoses (RfDs) developed by the EPA. The RfD, expressed in units of mg/kg/day,ia an estimate of the average daily exposure of individuals (includingsensitive individuals) which will result in no adverse health effects duringtheir lifetime. Exposure levels to contaminants in environmental media such asdrinking water are compared to the RfD, which provides a benchmark below whichadverse health effects are not expected to occur.

Agency verified RfDs are available for six (6) of the substances identified inthe ground water at the sites: carbon disulfide, carbon tetrachloride, and four(4) thiocarbamate pesticides (butylate, EPTC, molinate, and vernolate) Thesevalues are contained in Table 6.1. At present there are no Agency verifiedRfDs for the individual thiocyanate compounds.

The EPA's Carcinogen Assessment Group has developed cancer potency factors forestimating excess lifetime cancer risks associated with exposure to potentialcarcinogens. The cancer potency factor, measured in (mg/kg/day) , ismultiplied by the average intake of a potential carcinogen (in mg/kg/day) toprovide an estimate of the upper bound lifetime excess cancer risk associatedwith exposure at that intake level. The term "upper bound" reflects theconservative nature of the risks calculated using the cancer potency factor,;and they are therefore unlikely to be less than the actual cancer risks.

One of the substances at the site, carbon tetrachloride, has been classified byEPA as a class B2 carcinogen. The cancer potency factor for carbontetrachloride is 1.3 X 10"1 (mg/kg/day)"1.

6.3 Risk Characterization

This section quantifies the potential for adverse health effects due to siterelated chemical exposure. Because noncarcinogenic effects are assumed to havea threshold dose below which an adverse effect will not occur, and carcinogeniceffects are assumed not to have a threshold dose, risk estimates fornoncarcinogenic effects are determined separately from carcinogenic risks. Thepotential for noncarcinogenic health effects is assessed by dividing eachindicator chemical's exposure-route and duration-specific intake by thereference *M« (RfD). This ratio is called the Hazard Quotient (HQ). If theestimated icvtake is greater than the RfD, the HQ will exceed one (1). Byadding the> BQs for all contaminants within a medium or across all media towhich a given population may reasonably be exposed, the Hazard Index (HI) canbe generated. The HI provides a useful reference point for gauging thepotential significance of multiple contaminant exposures within a single mediumor across media.

The HQ for many of the individual contaminants exceeds unity for the maximumexposure scenario, and the HQ for both carbon tetrachloride and carbondisulfide exceeds unity for the average exposure scenario.

Excess lifetime cancer risks are determined by multiplying the intake level andthe cancer potency factor. These risks are probabilities that are expressed in

5 9 020-15-

acientific notation. An excess lifetime cancer risk of IxlC"6 indicatesthat, as a pl*usable upper bound, an individual has a one in one million chanceof developing cancer as a result of site-related exposure to a carcinogen overa 70-year lifetime under the specific exposure conditions at a site. TheAgency considers-individual cancer risks in the range of 10~4 to 10 asprotective. The 10 risk level is used as the point of departure forsetting cleanup levels at Superfund sites. The risk level associated with themaximum and average exposure to carbon tetrachloride is in the unacceptablerange (i.e. 10" ).

At the present time, individual exposure via the ingestion of contaminatedground water is not occurring. However, unacceptable risk levels for thebaseline assessment indicate that ground water treatment is necessary toprevent the potential human exposure to unacceptable levels of contaminants inthe future.

6.4 Environmental Risk

Environmental risk at the Stauffer LeMoyne and Cold Creek sites is present dueto the threat of migration of ground water to the Mobile River. The area is anatural habitat for a variety of invertebrates, amphibians, reptiles, fish,birds and mammals. Two species of concern are the American Alligator, which ison the list of threatened species, and the Alabama Red-Bellied Turtle, which.isproposed for the list. The adjacent Cold Creek site includes the Cold CreekSwamp for which the environmental risk will be addressed in the Record ofDecision for the Swamp operable unit.

7.0 DOCUMENTATION OF SIGNIFICANT CHANGES S117(b)

The preferred alternatives for the ground water and source operable units asspecified in the Proposed Plan is modification of an existing intercept andtreatment system, monitoring of Detection Monitoring wells to determine thenecessity for corrective action, and pilot testing of in-situ treatmenttechnologies for the Old Carbon Tetrachloride Wastewater Treatment Pond andother SWMUa. The specific technologies and SWMUs needing treatment will bedetermined during remedial design. No significant changes have occurred in theremedy described in the Proposed Plan.

8.0 DESCRI pOM OP ALTERNATIVES

Four alternatives were considered for remediation of ground water, whichcontains unacceptable concentrations of carbon tetrachloride, carbon disulfide,thiocyanates, end thiocarbamates. The maximum and mean concentrations detectedat different locations on the Stauffer LeMoyne site is listed in Table 6.1.The extent of the contaminant plume will be defined during the Remedial Designstage. The following remedial alternatives were considered:

8.1 Alternative 1 - No Action

Shut down existing intercept and treatment systemShut down CNA Wells

* No treatment of sources

5 9 021-16-

The first alternative is no-action, as required by Section 117(B) of theNational Contingency Plan (NCP). This would entail shutting down the existingintercept and treatment system, as well as the wells at the Courtaulds NorthAmerica property to the south, resulting in reverting the ground water flowdirection toward*the*Mobile River. This would allow for potential migration ofthe contaminants in the aquifar toward water supply wells and the Mobile River,increasing the likelihood of exposure to workers on site via ingestion ofground water and enhancing the risk to aquatic life. The levels ofcontamination would gradually be reduced via natural processes, but at a veryslow rate.

8.2 Alternative 2 - Existing Ground Water Interceptand Treatment System with Surface Water Discharge

Continued use of existing intercept and treatment system* Surface water discharge to Mobile River* Monitoring of effluent, ground water concentrations and

pumping rates

Alternative 2 involves the ground water intercept and treatment system which iscurrently in operation at the Stauffer LeMoyne site. Ground water is pumpedfrom three extraction wells (Figure 8.1), located south of the Old CarbonTetrachlcride Plant Hastewater Treatment Pond, and into the treatment system.Treatment consists of aeration via spray-nozzles which discharge the groundwater to the treatment pond and then to the Mobile River. The surface waterdischarge is regulated by the National Pollutants Discharge Elimination System(NPDES) permit aa required under the Clean Water Act, for which standards arecurrently being met. However, it is unclear whether the extraction system isreducing contaminant concentrations in the ground water to the cleanupstandards listed in Table 8.1. Applicable or relevant and appropriaterequirements (ARARs) and "to-be-considered" health-based levels (TBCs) fromwhich these cleanup levels were developed are also listed in this table.Periodic ground water monitoring would be included in this remedial action todetermine if the ground water quality was improving at an acceptable rate.

A major assumption underlying this alternative includes the continued pumpingof the CNA wells to the south. In the event these would be shut down, theremedy would be jeopardized due to changes in ground water flow direction whichwould redueg* the ability of the existing extraction wells to capture theplume. Add ional interceptor wells would be required to maintain gradientcontrol anfrminimize off-site migration of contaminants.

8.3 Alternative 3 - Modified Ground Water Intercept andTreatment System with Surface Water Discharge

Continued use of existing intercept and treatment systemInstallation of additional extraction wellsModifications to treatment system to be determinedMonitoring of effluent, ground water concentrations andpumping rates

Colil Clank

CC 12

IM 10

IM ;

IVI

old Creek Plant

aMoyna PlantII 012 LM4

0 4 6 0 4 7 ^°-«l9:4';

O 44 O 46

LM6

Explanation:• Wall Location

Dunking Water Well Locution

3OO

0 60O Fl.Approximate Scala

N(Modified Alter COM. 1986 And Suiillei. 1978)

cn

CDK3^o

8.1 Site Area Well Locations

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TABLE 8.1- GROUND WATER CLEANUP GOALS

Chemical

Carbon Disulfide

Carbon Tetrachloride

Cyanide

Mercury

Thiocyanates.

Thiocarbamates

Butylate

Cycloate

EPTC

Molinate

Pebulate

Vernolate

Goal rua/H

700

5

200

2

200*

350

7 ***

210

14

7 ***

7 **

Basis

LHA

MCL

LHA

MCL

LHA

LHA

LHA

LHA

LHA

LHA

LHA

MCL - Maximum Contaminant Level

LHA - Lifetime Health Advisory, based on RfD, 70 kg human2 liter/day water consumption, 20% relative sourcecontribution

* - No Agency health-based number exists forthiocyanates. The LHA for the more toxic cyanideis used.

** - These cleanup goals could be increased a maximum offourfold pending an EPA Office of Drinking Waterdecision to revise the LHA values for thesecarbamate herbicides that allows a drinking watersource contribution up to 80% of the RfD.

*** - No Agency-verified RfDs for these chemicals; thecleanup goal is based on the RfD for vernolate(the most toxic thiocarbamate at the site)

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Alternativa 3 involves a modification of the exiating intercept and treatmentsystem. Additional extraction wells would be installed, baaed on ground waterquality characteristics, water-table gradients, and pumping activities at thesite and adjacent properties. This alternative would allow for a more rapidachievement of the cleanup goals mentioned for Alternative 2. Surface waterdischarge must meet concentration limits specified in the NPOBS permit. Inaddition, as for the previous alternative, a contingency plan would benecessary in case pumping of the CNA wella was terminated. Also, ground watermonitoring would be conducted to determine the progress of the remediation.

8.4 Alternative 4 - Existing Ground Water Intercept andTreatment System with Surface Water Discharge and

In-Situ Vapor Extraction

Continued operation of existing intercept and treatment systemRemoval of accumulated rainwater, aoil, and sludge from the OldCarbon Tetrachloride Plant Wastewater Treatment PondIn-Situ vapor extraction of eoil beneath the Old CC14 Plant WWTPond

* o&M of vapor extraction unit* Monitoring of effluent and pumping rates

This alternative includes continued operation of the existing intercept and ;treatment system coupled with in-situ treatment by vapor extraction of thecontaminated soil underlying the Old Carbon Tetrachloride Plant WastewaterTreatment Pond area. Bench-scale teats would be performed and sludge andaccumulated rainwater would be removed from the pond prior to installation ofthe treatment system. Vapor extraction involves injection of clean air intosoil containing volatile organic constituents. The constituents volatilize andthe contaminated air would then be withdrawn via a vacuum and vented through anemission control system. Treatment of the pond area would expedite groundwater remediation activities and attainment of cleanup standards by reducingleaching of contaminants into the ground water but would not effect groundwater of contaminants from other sources. NPDES permit discharge limits willneed to be met for all contaminants. As in Alternatives 2 and 3 a contingencyplan would be required for possible shutdown of the CNA wells, and ground watermonitoring would be conducted to evaluate progress of the remedy.

9.0 SUMMAJUf OF COMPARATIVE ANALYSIS OF ALTERNATIVES

The major objective of the Feasibility study (PS) was to develop, screen, andevaluate alternatives for remediating the Stauffer LeMoyne and Cold Creeksites. This decision document deals with the ground water, for which severalremedial technologies were identified. These technologies were screened basedon their feasibility given the contaminants present and site characteristics.Those which remained after the initial screening were evaluated in detail basedon the nine criteria required by SARA, which are listed below:

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1) Overall protection of human health and the environment;2) Compliance with applicable or relevant and appropriate requirement!

(ARARs)3) Long-term effectiveness4) Reduction of toxicity, mobility or volume5) Short-term effectiveness6) Implementability7) Cost8) State acceptance9) Community acceptance

Cost was used to compare alternatives only when they provided similar degreesof protection and treatment. Four alternatives remained after the detailedevaluation and were listed in the previous section. A summary of the relativeperformance of the alternatives with respect to each of the nine criteria isprovided in this section.

9.1 Protectiveness of Human Health and the EnvironmentThe no-action alternative is not protective of human health and the environmentbecause it allows off-site migration of the contaminants, leading to possibleingestion of water from wells drilled into the surficial aquifer. Alternatives2 and 4 would not be protective because contaminants have been detectedoff-site while the existing intercept and treatment system has been in >operation. Alternative 4 may eliminate the source of carbon tetrachloride butwill not deal with the thiocarbamates and other pollutants. Alternative 3 ispotentially more protective than the other three, since additional extractionwells will be strategically placed to capture the contaminant plume.

9.2 Compliance with ARARsAlternatives 1 and 2 do not comply with applicable or relevant and appropriaterequirements (ARARs). Concentrations of hazardous substances in the groundwater currently exceed EPA approved standards. Alternative 4 may help to meetthe cleanup standards for carbon tetrachloride but not for the othercontaminants. Addition of extraction wells in a modified ground waterintercept system and source treatment, as described in Alternative 3, wouldcomply with ARARs if properly designed.

The primary ARARs for the ground water are maximum concentration limits (MCLs)under the 9&t* Drinking Hater Act (SDWA). These are applicable where waterwill be profited directly to 25 or more people or will be supplied to 15 ormore servioS-connections. MCLs are relevant and appropriate where the surfacewater or ground water is being used or may potentially be used for drinkingwater. The LaMoyne facility has two drinking water wells which provide waterfor 230 employees. Cold Creek has one drinking water well, and a backup wellserving 250 employees. Neighboring businesses also utilize well water fordrinking purposes and there are approximately 21 residential water wells withina two-mile radius. Other ARARs that must be complied with are surface waterdischarge requirements of the National Pollutant Discharge Elimination Systemcovered under the Clean Water Act (CWA). Air emissions specificationsestablished by the Clean Air Act must also be met. EPA has determined thatRCRA technical standards regarding corrective action and closure are relevantan appropriate for the SWMUa (ponds and landfills) at this site. RCRA LandDisposal Restrictions will be in effect once the contaminants have been

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extracted froa the ground water. These restrictions require treatment prior toredisposing the wastes.

The no-action alternative does not comply with the SDWA ARARs because it doesnot reduce ground water contaminant concentrations to MCLs. The existingground water intercept system, Alternative 2, has not achieved these limits.Alternative 4 may meet these limits for carbon tetrachloride but not the othercontaminants. All alternatives would comply with the NPDES permits for surfacewater discharge. Compliance with RCRA will be determined through monitoring ofthe Detection Monitoring wells. Alternative 3, if properly designed, wouldcomply with all ARARs.

9.3 Reduction of Toxieitv. Mobility, or VolumeAll alternatives except for no action would reduce the toxicity and volume ofthe ground water contamination by decreasing the size of the plume and/oreliminating part of the source. Alternatives 2 and 4 may actually increasemobility of the contaminants by pulling them from the sources lying somedistance from the extraction wells.

9.4 Short-term EffectivenessThe alternatives will require varying amounts of time to achieve cleanup of thesite. None will be immediately effective upon completion of construction.Alternative 3 would require the shortest remediation time because it would [remove the major sources of contamination and capture the ground water plumesmore quickly. Any short-term risk to workers involved in construction of theremedy would be reduced through implementation of a health and safety plan.

9.5 Long-term EffectivenessLong-term effectiveness and permanence would be provided only by Alternative 3,assuming future treatment of source units. Alternatives 2 and 4 would notprovide long-term effectiveness because they would allow off-site migration tocontinue. The no-action alternative is not effective in the short or longterm.

9.6 ImplementabilitvThe implementability of each alternative is based on technical feasibility,administrative feasibility and the availability of services and materials. Allalternatives are technically and administratively feasible. All involvetechnologies which have been used in the past and have a demonstratedperfonnancs iptcord. An intercept and treatment system is already in place andis meeting^IpyDKS permit requirements. A modified system would simply requireinstallation of additional extraction wells and is therefore easily attainable.

9.7 CoatThere would be no cost associated with Alternative 1. Since the ground waterintercept and treatment system is already in place, a relatively low cost of$1,355,100 is estimated for Alternative 2. This cost includes repair of thetreatment pond and Operations and Maintenance (O&M) costs. For Alternative 3,it was assumed that three additional extraction wells would be installed andthat the only ground water constituents being treated are carbon tetrachlorideand carbon disulfide. However, thiocyanates and thiocarbamates will also

5 9 027.-22-

require treatment. Therefore, the estimated total capital cost for wellinstallation and O&M of the system of $3,119,200 may be low. Alternative 4involves in-situ vapor extraction in addition to the existing treatmentsystem. This would raise the estimated capital cost from that of Alternative 2to $2,006,100. -

9.8 State and Community AcceptanceThe State of Alabama as represented by the Alabama Department of EnvironmentalManagement is in favor of a modified ground water intercept and treatmentsystem for remediating the ground water at the Stauffer sites. Based oncomments made by citizens at the public meeting held on July 27, 1989, andthose received during the public comment period, the community believes atreatment system will effectively protect human health and the environment.

10.0 THE SELECTED REMEDY

Based on available data and analysis conducted to date, the US EPA selectsAlternative 3 as the most appropriate solution for meeting the goals of theinitial ground water operable unit at the Stauffer LeMoyne and Cold Creeksites. This alternative involves continued operation of the existing interceptand treatment system along with the installation of additional extractionwells. Ground water concentrations exceeding the cleanup goals listed in Table8.1 must be reduced through treatment in order to achieve and an acceptable ;risk level. Operation and maintenance includes monitoring of contaminantlevels in the ground water and the treatment system effluent as well asmaintenance of the components of the system itself.

EPA has decided that bench and/or pilot scale testing of in-situ treatmentalternatives for some SWMTJs, including the Old Carbon Tetrachloride PlantWastewater Treatment Pond, is appropriate as part of the Remedial Design. Arange of treatment technologies including thermal desorption and vaporextraction is being considered, and a formal remedy for these response areaswill be incorporated in a future Record of Decision.

As part of the modified ground water intercept and treatment system, DetectionMonitoring wells will be designated and/or installed around the ponds andlandfills for contaminant detection purposes. Upon detection of contaminantsabove cleanup standards, these wells will be redesignated as Point ofCompliance (JPOC) wells. Data from the wells will be utilized to determineexact locrttone of the contaminant plumes and to design ground water extractionmodificattsj , which will ensure that off-site ground water activities will notdetrimentally effect remediation of the Stauffer sites. Ground water modelingwill be employed to design and verify any extraction modifications.Information from the Detection Monitoring wells will also help determine whichsource units are in need of CERCLA remedial or RCRA corrective action.

Already in existence are RCRA and NPDES permits which regulate ongoinghazardous waste and surface water discharge activities, respectively. EPA andADEM are the designated agencies for enforcing these permits.

The rationale for choosing this alternative includes the following reasons.The alternative:

' provides immediate protection to human health from the potential threatsassociated with consumption of ground water;

5 9 028--23-

' reverses the continued migration and expansion of the contaminant plumeand prevent* off-site migration;

provides for management of surface water quality through monitoring ofcontaminant- levels in the surficial aquifer and possible surface waterdischarges;

' is consistent with additional site actions and will be compatible with thefinal site remedy;

' contributes to the implementation of a more permanent remedy at the site;

* allows for a more complete and expeditious remediation of the ground waterthan the other alternatives.

The goal at the completion of the entire remedial action is to meet the groundwater cleanup standards listed in Table 8.1 at each of the designated DetectionMonitoring wells as well as at the extraction wells. These wells will bemonitored for 30 years. If a release is detected at a Detection Monitoringwell, it will be redesignated as a Point of Compliance well and CERCLA remedialor RCRA corrective action will be instituted at the appropriate SWMU.

11.0 STATUTORY DETERMINATIONS

The US EPA and ADEM have determined that this remedy will satisfy the followingstatutory requirements of section 121 of CERCLA: protection of human health andthe environment, attaining ARARs, cost-effectiveness, and utilization ofpermanent solutions and alternative treatment technologies to the maximumextent practicable.

11.1 Protection of Human Health and the Environment

The selected remedy adequately protects human health by reducing the riskof consumption of contaminated ground water. This will be accomplishedthrough the prevention of off-site migration and the capture of the groundwater contaminant plume. Environmental risk will be reduced by directingthe plume away from the Mobile River. No unacceptable short-term riskswill r*sxalt from the implementation of this remedy.

n ? flttii-nment °* Applicable or Relevant and Appropriate Requirements

This reoedy assures that drinking water supplied to current well userswill meet available MCLs under the Safe Drinking Hater Act (SDWA). Forthose chemicals which do not have assigned MCLs, to-be-consideredhealth-baaed values will be attained. Discharge from the ground watertreatment system will meet NP1 3 permit discharge limits under the cleanWater Act (CWA). Compliance with RCRA technical standards will beachieved through corrective action on any SWMUs that are determined to bereleasing contaminants to the ground water. The CWA is an applicablerequirement, while the SDWA (MCLs) and RCRA are relevant and appropriate.

5 9 029-24-

rtivenesa

The selected alternative, although more costly than the others, provides ahigher degree of protectiveness. The modified ground water intercept andtreatment system will protect well users from ingestion of contaminatedground water by capturing the plume and reducing the contaminantconcentrations to health-based levels. It will also provide a more rapidattainment of these levels and assist in the remedial action for the otheroperable units. The total capital cost of this alternative is$3,119,200. The US EPA has determined that the costs of the selectedremedy are proportionate to the overall effectiveness and is a reasonablevalue for the money.

11.4 Utilization of Permanent Solutions and Alternative Treatment orResource Recovery Technologies to the Ma.xi.nmin Extent Practicable

The US EPA has determined that the selected remedy provides the bestbalance among the nine evaluation criteria for the four alternativesevaluated. The selected remedy was the only alternative to providedefinite protection of human health and the environment, to reduce themobility of the plume and to be effective in the long term. The remedycontributes to and is consistent with future remedial actions at thissite. It represents the maximum extent to which permanent solutions an4treatment can be practicably utilized for this operable unit.

11.5 Preference for Treatment as a Principal El**Bent

The statutory preference for treatment will be met because the principalthreat from the Stauffer sites is ingestion of contaminated groundwater. In additon, contaminated soils or sludges at the SWMUs aresources of ground water contamination. The selected remedy will reducethis risk through capture of the ground water plume and treatabilitytesting of the contaminant sources.