Woodward-Clyde Consultants · E.I. du Pont de Nemours and Company, Inc. (Du Pont) and...

Woodward-Clyde ConsultantsPennsylvania 19462215-825-3000Fax 215-834-0234

,;€V

December 23, 1991 ;V88C2076-4X «K?>"

dr** -Mr. Randy Sturgeon 'V -;Enforcement Project ManagerU.S. Environmental Protection Agency ' r. '"'', \\Region 3, 841 Chestnut Street r-H>^ '''Philadelphia, PA 19107 *

Re: Draft Focused Feasibility StudyDu Pont-Newport Site

Dear Mr. Sturgeon:

E.I. du Pont de Nemours and Company, Inc. (Du Pont) and Woodward-Clyde Consultants(WCC) are pleased to submit by courier to the EPA six copies of the Draft Focused FeasibilityStudy (FFS) for the Du Pont-Newport Site. This FFS has been prepared and is being submittedin accordance with the Administrative Consent Order signed by Du Pont and the EPA.

Please do not hesitate to call Mr. Roger Gresh at WCC or Mr. Joel Karmazyn at Du Pont ifyou have any questions.

Very truly yours,

C C James V. Husted, PESenior Project Engineer

Roger T. Gresh, P.G.Project ManagerRTG/kcs/DPN4cc: K. Kalbacher, DNREC

S. Sury, CIBA-GEIGYF. Hannigan, CIBA-GEIGYB. Butler, Du PontJ. Karmazyn, Du PontN. Griffiths, Du PontG. Foley, Du PontC. Trmal, Du PontA. Hirsch, WCC

Consulting Engineers, Geologistsand Environmental Scientists

Offices in Other Principal Cities ft D O j 9 fj f) Q ^^^

DRAFT

I I I I I I FOCUSED FEASIBILITY STUDYDU PONT-NEWPORT SITENEWPORT, DELAWAREDECEMBER 23, 1991

Prepared for:

U.S. Environmental Protection AgencyRegion 3841 Chestnut StreetPhiladelphia, Pennsylvania 19107

Submitted by:

E.I. du Pont de Nemours and Company, Inc.Du Pont ChemicalsBOD 918-141007 Market StreetWilmington, Delaware 19898

Woodward-Clyde Consultants5120 Butler PikePlymouth Meeting, Pennsylvania 19468

Project No. 88C2076-4XftR3!20IO

Woodward-Clyde Consultants

TABLE OF CONTENTS - continued

Section Page No.

3.1.1 Source Control Considerations 3-23.1.2 Institutional Control Considerations 3-33.1.3 Extraction Technology Considerations 3-43.1.4 Treatment Technology Considerations 3-53.1.5 Containment Technology Considerations 3-63.1.6 Summary of Groundwater Technology

Pre-Screening 3-7

3.2 SOIL TECHNOLOGY PRE-SCREENING 3-9

3.2.1 Institutional Control Technologies 3-93.2.2 Containment Technologies 3-103.2.3 Removal Technologies 3-113.2.4 Treatment Technologies 3-123.2.5 Disposal Technologies 3-133.2.6 Summary of Soil Technology

Pre-Screening 3-13

4.0 DEVELOPMENT, EVALUATION AND COMPARISONOF ALTERNATIVES 4-1

4.1 DEVELOPMENT OF ALTERNATIVES 4-1

4.1.1 Ballpark 4-14.1.2 North Disposal Site and

Associated Wetlands Alternatives 4-24.1.3 South Disposal Site and

Associated Wetlands Alternatives 4-5

4.2 EVALUATION AND COMPARISON OFALTERNATIVES 4-8

4.2.1 Ballpark 4-8

4.2.1.1 Ballpark AlternativesEvaluation 4-8

4.2.1.2 Ballpark AlternativesComparison . 4-9

SR3I20I2


TABLE OF CONTENTS - continued

LIST OF TABLES

TABLE 1-1 HYDROSTRATIGRAPfflC UNITS

TABLE 2-1 NEWPORT SITE GROUNDWATER ARARS

TABLE 2-2 WATER QUALITY CRITERIA FOR THEPROTECTION OF FRESHWATER AQUATIC LIFE

TABLE 2-3 SUMMARY OF PHASE HI GROUNDWATERMCL EXCEEDANCES

TABLE 2-4 SUMMARY OF SURFACE WATER QUALITYCRITERIA EXCEEDANCES

TABLE 3-1 GROUNDWATER TECHNOLOGY PRE-SCREENING

TABLE 3-2 SOIL TECHNOLOGY PRE-SCREENING

TABLE 4-1 EVALUATION AND COMPARISON OFALTERNATIVES, BALLPARK AREA OF INTEREST

TABLE 4-2 EVALUATION AND COMPARISON OFALTERNATIVES, NORTH DISPOSAL SITEAREA OF INTEREST

TABLE 4-3 EVALUATION AND COMPARISON OFALTERNATIVES, SOUTH DISPOSAL SITEAREA OF INTEREST


EXECUTIVE SUMMARY

On July 22, 1988, E.I. du Pont de Nemours and Company, Inc. (Du Pont) signed anAdministrative Consent Order (AGO) with the U.S. Environmental Protection Agency (EPA)for the Du Pont-Newport Superfund Site (Site). The AGO required a Remedial Investigation(RI) and Feasibility Study (FS) to be prepared in accordance with certain objectives. Du Pontand Woodward-Clyde Consultants (WCC) have prepared this Focused Feasibility Study (FFS)to address the FS objectives in the AGO within the ACO-driven schedule in conformance withEPA's guidance documents under CERCLA.

In accordance with the National Oil and Hazardous Substances Contingency Plan (NCP), theApplicable or Relevant and Appropriate Requirements (ARARs) that can be identified withthis specific Site are related to surface water, groundwater and wetlands protection. TheseARARs include the maximum contaminant levels (MCLs) established in the Safety DrinkingWater Act (SDWA), surface water quality criteria developed under the authority of the CleanWater Act (CWA), wetlands preservation statues including the CWA, Fish and WildlifeCoordination Act, and Delaware State Wetlands Act.

The human health evaluation showed that all estimated cumulative carcinogenic risks werebelow or well within the EPA's acceptable risk range of 10"4 to 10"6 for both current and futureland use scenarios. The environmental evaluation identified several Site-related wetlandsampling stations where sufficient biological evidence was present to infer impacts that arelikely due to metal toxicity.

Based on the data submitted in the Draft Remedial Investigation, the Draft Human HealthEvaluation and Draft Environmental Evaluation identified potential unacceptable human healthrisks and environmental impacts for the following Areas of Interest (AOIs):

• Ballpark• North Disposal Site and Associated Wetlands• CIBA-GEIGY Plant Operations Area

FFS Rpt/Du Pont-Newport/88C2076-4X/DPN4 ES-1 12-23-91

flR3!20!6


1.0INTRODUCTION

1.1 FOCUSED FEASIBILITY STUDY OBJECTIVES

On July 22, 1988, E.I. du,Pont de Nemours and Company, Inc. (Du Pont) signed anAdministrative Consent Order (AGO) with the U.S. Environmental Protection Agency (EPA)for the Du Pont-Newport Superfund Site (Site). The AGO required a Remedial Investigation(RI) and Feasibility Study (FS) and outlined the following objectives for the FS:

Determine and evaluate alternatives for remedial action to prevent, mitigate orotherwise respond to orremedy the/release or threatened release of hazardoussubstances, pollutants, or contaminants from the Site.

Consider the range of alternatives described in the Comprehensive EnvironmentalResponse, Compensation and Liability Act of 1980 (CERCLA) and in Section300.68(f) of the National Oil and Hazardous Substances Contingency Plan (NCP)during alternative evaluation.

• Evaluate remedial activities that utilize permanent solutions and alternativetreatment technologies to the maximum extent practicable.

• Address factors required to be considered by Section 121 of the SuperfundAmendments and Reauthorization Act of 1986 (SARA) when evaluatingalternatives.

Du Pont and Woodward-Clyde Consultants (WCC) prepared this Focused Feasibility Study(FFS) to address the ACO FS objectives listed above within the context of Du Font'sunderstanding of the FFS scope and content agreed upon between the EPA and Du Pont duringtheir November 27, 1991 meeting.

FFS Rpt/Du Pont-Newport/88C2076-4X/DPN4 1-1 12-23-91


WCC Report Title_____ Date Issued to EPA

Draft Risk Assessment-Volume II (Environmental July 30, 1991Evaluation) Du Pont-Newport Site

Draft Risk Assessment-Volume I (Human Health October 14, 1991Evaluation), Du Pont-Newport Site

Draft Remedial Investigation Report, November 1, 1991Du Pont-Newport Site

1.3 SITE SETTING

The Site is located to the south of the City of Newport, Delaware and is bisected by theChristina River as shown on Figure 1-1. The study area for the RI at the Site consisted of: anoperations area (consisting of the CIBA-GEIGY Newport Plant area and the Du Pont HollyRun Plant area); two inactive landfills labeled the North Disposal site and the South Disposalsite; the associated wetlands; the associated segment of the Christina River; the potentiallyimpacted groundwater; and a small recreational area (Ballpark) located immediately northwestof the operations area.

1.3.1 Site Geology

Detailed interpretation of the Site geology was presented in the Data Sufficiency Report (WCC,May 17, 1991). Two cross-sections of this Site (Figure 1-2) profile the geology from north tosouth (Figure 1-3) along the eastern side of the Site, and from east to west (Figure 1-4) acrossthe CIBA-GEIGY and Holly Run Plant Operations Areas. Table 1-1 describes the depths andelevations of the hydrostratigraphic units encountered.

The crystalline rocks of the basement encountered at the Site are highly weathered (saprolite).This weathered zone is interpreted to be at least 35 feet thick. Competent rock was neverpenetrated during the three phases of the RI. The top of bedrock surface is interpreted to dip

FFS Rpt/Du Pont-Newport/88C207fr4X/DPN4 1-3 12-23-91

AR3I2020


Other naturally occurring Quaternary deposits have been interpreted to overlie the ColumbiaFormation. In pre-Phase HI work, these were identified as marsh deposits; however, theyinclude fine sands and minor, medium to coarse sands, which probably have fluvial origins. Theoccurrence of these deposits ranges from ground surface to a depth of 18.7 feet below groundsurface, depending on the quantity of fill placed in the area. These deposits, including fine-grained, often organic strata, were encountered across the Site at 36 locations. The thicknessand elevation of the fine-grained beds varied considerably. Sand lenses, up to several feet thick,occasionally occurred between them, suggesting a fluctuation of transport energy characteristicof stream deposits. Although the fine-grained beds appear to be discontinuous across the Site,their existence may provide a partial aquitard to groundwater percolating through the surficialdeposits in some areas.

Fill is found in most of the Holly Run and CIBA-GEIGY Plant areas. It appears to beprimarily repositioned material from the Columbia Formation and other Quaternary deposits.Due to the fact it is largely reworked native material, it was often difficult to distinguish fromnatural deposits. The presence of debris and absence of sedimentary structures were the maincriteria for identification. In addition, the appearance of an organic bed below several feet ofsand and gravel usually marked the base of the fill or other Quaternary deposits. The lack ofsuch a marker bed or other evidence might have led, in some cases, to fill being erroneouslyidentified as Columbia Formation or other Quaternary deposits during Phase I and II of the RI.The fill ranged in thickness from 0 to 23 feet with a typical thickness of 8 to 12 feet. Only sixlocations, all occurring in the wetlands on the south side of the Christina River or to thewestern edge of the Site on the north side of the river, did not show fill. As the fill is aheterogenous mixture of the surficial deposits and some materials derived from the ores usedin the historic manufacturing operations, no consistent permeable or semi-permeable stratawere interpreted.

1.32 Wetlands

The following summary of. wetland conditions was developed during the RI (WCC, January 1990and July 30, 1991). Wetlands are those areas that are inundated or saturated by surface orgroundwater at a frequency and duration sufficient to support, and that under normal

FFS Rpt/Du Pont-Newport/88C207&4X/DPN4 1-5 12-23-91

AR3I2022


1.4 AREAS OF INTEREST

Based upon evaluations hi the RI Report and the Risk Assessment documents the following sixAreas of Interest (AOIs) with their related media, were identified:

_________Area of Interest________ Related Media

• Ballpark Surface Soil

• North Disposal Site and Associated Wetlands SoilSurface WaterSedimentsGroundwater

• CIBA-GEIGY Plant Operations Area SoilSedimentGroundwater

• South Disposal Site and Associated Wetlands SoilSurface WaterSedimentsGroundwater

• Christina River Surface WaterSediments

• Holly Run Plant Operations Area SoilGroundwater


AR3I2021*

Woodward-Clyde Consuftanf s

1.52 North Disposal Site and Associated Wetlands

The North Disposal site was originally identified as a seven-acre inactive landfill bounded bythe Holly Run and CIBA-GEIGY Plant Operation Areas, and the Christina River (See Figure1-2). The landfill is primarily covered with maintained grass and rimmed with pine trees andother heavy vegetation. Except in areas sloping toward the drainageway, the surface elevationfor most of the landfill is approximately 20 to 25 feet above mean sea level and at least 10 feetabove the shallow water table.

A drainageway surrounds the northern and western edge of the landfill and empties intowetlands connected to the Christina River. Erosion has created a small pool of standing water("sunfish pond") where the drainageway empties into the wetlands. Review of North Disposalsite drainageway surficial sediment analyses (WCC, July 30, 1991) shows that levels of allconstituents of concern exceed the sediment Threshold Value guidelines (see Section 2.1). Thispotential environmental exposure to constituents of concern is beh'eved to have been causedwhen the drainageway was created.

In addition to the seven-acre landfill, the area to the west of the drainageway (known as the"concrete jungle") is approximately 1 acre hi size and contains concrete-rubble and otherconstruction debris. The topography is irregular and the debris is covered in most areas witha thin veneer of soil. The Draft RI Report (WCC, November 1, 1991) shows the "concretejungle" included in the redelineated North Disposal site area.

Based on records of disposal history, materials known or beh'eved to have been deposited at theNorth Disposal site include plant debris such as off-grade imitation marble counters, empty steeldrums, metal alloys, liquid wastes and pigment muds (WCC, July 28, 1988). After disposalceased in 1974, the North Disposal site was capped with about two feet of clayey soil andvegetated.

A steep embankment (varying between 1:1 and 2:1 slope) forms the North Disposal siteboundary with the Christina River. This embankment is mostly vegetated with brush and sometrees. There is, however, a small area of exposed fill material potentially containing


ftR3i2026


was a specialty metal produced on-site for a brief period of time. Because on-site radiationlevels are within background levels, the thoriated wastes are not considered an issue of concernat the Newport Site.

The majority of the CIBA-GEIGY Plant Operations Area is covered with buildings, concrete,or macadam. The ground surface in this operations area generally slopes to the east from anelevation high of approximately 25 feet above mean sea level in the western end of the area toa low of approximately 10 feet at James Street.

1.5.4 South Disposal Site and Associated Wetlands

The South Disposal site constitutes 15 acres of a 45-acre tract of land owned by Du Pont onthe south side of the Christina River. The elevated northern one-third of the tract is theinactive landfill known as the South Disposal site. Waste disposal took place fromapproximately 1902 to 1953. Materials deposited in the South Disposal site consisted primarilyof nearly insoluble residueTol zincfand barium ores from Lithopone production, which werepumped as a slurry to the landfill through a pipeline across the Christina River. In 1973, theState of Delaware Department of Highways deposited about 130,000 cubic yards of variablesoils from highway construction over the South Disposal site, covering it up to an average depthof about three feet (WCC, July 28, 1988). The deposited soil functions as a cover for theinactive landfill and supports moderate to heavy vegetation with a variety of wildlife.

The previous landfilling operations resulted in grade elevations ranging from a high ofapproximately 16 feet above mean sea level in the northern portion of the landfill toapproximately 4 feet in the wetlands area immediately south of the landfilled area. The SouthDisposal site exhibits a gentle grade, north to south, with a steepening slope near the southernedge of the filled area and a northwestern slope along the riverbank itself. An existing diketraverses the center of the tract in an east-west direction, curving in a northerly direction at theeastern and western boundaries of the landfill. This dike has steep side slopes and anapproximately 25-foot wide crest with a typical elevation of about 12 to 13 feet above mean sealevel. A breach exists in the dike near its southwestern corner. Overhead high-voltage power

FFS Rpt/Du Pont-Newport/88C2076 X/DPN4 1-11 12-23-91

5R3J2028


The constituents of concern in the soils, surface water and sediments associated with this AOIare metals related to the Lithopone slurry waste disposal (barium, zinc, cadmium, and othertrace metals associated with the barium and zinc ores).

1.5.5 Christina River

The Christina River is used for recreation in the vicinity of the Site. The width of the ChristinaRiver between the North and South Disposal sites ranges from approximately 160 to 330 feet.Tidal influence of the Delaware River, which is about 7.5 river miles from the Site, extends pastthe Site to approximately 15 miles upstream from the confluence of the Christina and DelawareRivers. The mean tidal range of the Christina River at the Site varies between 5 to 6 feet.

The substrate of the Christina River in the Site area is variable. Sediments range from silts andmuds in depositional areas, to predominantly sands in erosional areas, with areas adjacent tothe Site underlain by rubble, rip-rap and various types of urban refuse. In general, subsurfacesediments (below 6-12 inches) are composed of stiff, grey clay.

Like the South Disposal site AOI, the constituents of concern investigated for the ChristinaRiver are related to the Newoort Site historic operations.

1.5.6 Holly Run Plant Operations Area MjQ $1

New facilities were constructed for the chromium dioxide powder production in 1979 and wereretained by Du Pont as the Holly Run Plant, when the remainder of the operations area wassold to CIBA-GEIGY in 1984. The only constituent of interest associated with the Holly RunPlant manufacturing operations is chromium.

The majority of the Holly Run Plant Operations area is covered with buildings, concrete, ormacadam. The ground surface generally slopes to the south from an elevation high ofapproximately 30 feet above mean sea level in the northwestern end of the Holly Run Plantoperations area to a low of approximately 17 feet at the northern side of the North Disposalsite.



• Section 2.0: Remedial Action Objectives - This section summarizes applicableor relevant and appropriate requirements (ARARs), the Human HealthEvaluation, the Environmental Evaluation, and the scope of the remedial goals.

• Section 3.0: Identification and Evaluation of Remedial Technologies - Potentialtechnologies are identified and screened for groundwater and soils in this section.

• Section 4.0: Development and Evaluation of Alternatives - Alternatives for theimpacted AOIs are compared against one another in this section.

• Section 5.0: Summary and Conclusions - This section summaries the conclusionsreached during the FFS preparation process and identifies a recommendedremedial alternative for each impacted AOI.

FFS Rpt/Du Pont-Newport/88C20764X/DPN4 1-15 12-23-91

AR3I2032


shown in Table 2-1. Other ARARs that may be identified for this Site are associated withwetlands, floodplains, and disposal restrictions, and RCRA standards.

The maximum contaminant levels (MCLs) established under the Safe Drinking Water Act(SDWA) are enforceable standards set for public water supply systems. The NCP states that"MCLs are relevant and appropriate to the cleanup of groundwater that is, or may be, used fordrinking." EPA has classified the Columbia and Potomac Aquifers as Class 2A drinking watersources; therefore, the MCLs of Table 2-1 are applicable and relevant for Columbia andPotomac Formation groundwater at the Site. The MCLs are not applicable to groundwater inthe saturated zone of the fill material#nirfCsite. I The preamble to the NCP clarifies that themaximum contaminant level goals (MGLGs) ropy also be relevant and appropriate where therisk posed by multiple contaminants x rpatjjways that are in excess of 10"4. Because the humanhealth evaluation did not identify any risks greater than 10"4 for groundwater ingestion, theMCLGs are neither applicable nor relevant and appropriate for this Site.

Primary wetland ARARs pertinent to the Site are Section 404(b)(l) of Clean Water Act (CWA)and the Fish and Wildlife Coordination Act. The goal of these laws is no net loss of wetlandseither in function or value. Another potential ARAR is the Delaware State Wetlands Act,. which pertains to tidal wetlands.

Criteria for surface water quality were promulgated by the USEPA in 1986 and by theDelaware Department of Natural Resources and Environmental Control (DNREC) in 1990.These criteria were developed under the authority of the CWA. The water quality criteria areconsidered to be ARARs for this Site due to the presence of surface water in the wetlands anddrainageways associated with the Newport Site on both the north and south side of theChristina River. The water quality criteria for the protection of fresh water aquatic life areshown in Table 2-2.

The groundwater concentration exceedances of the MCLs in the appropriate AOIs (see Section1.4) are shown in Table 2-3. The exceedances of the water quality criteria for the surface waterat the Site are shown hi Table 2-4.



contaminated subsurface soils during soil boring and other intrusive activities should reducefuture worker exposure below the values estimated in the Site Draft Human Health Evaluation.

Based solely on dispersion modeling, cumulative hazard indices for the hypothetical ingestionof groundwater at Old Airport Road exceed unity. Cobalt and cadmium were the majorcontributors to this calculated hazard. The potential risk associated with cobalt is consideredto be greatly over-estimated due to the reference dose (RfD) selected for cobalt. The hazardindices are also considered very conservative because attenuation and retardation of chemicalsdnringtransport were not considered during modelling groundwater concentrations?: A veryconservative RfDJpfcobalt was used at the direction of EPA Region HI. Furthermore,rnture-instaTlation of public water supply wells along Old Airport Road is considered unlikelydue to land use and low yield of the Potomac Formation water bearing units in the area._

The EPA Region IE and Du Pont agreed to using an action level of 500 ppm for lead insurface soils in areas where children or adolescence are likely to be present and an action levelof 1000 ppm for lead in surface soils in areas where only industrial exposure is anticipated.

2.3 SUMMARY OF ENVIRONMENTAL EVALUATION

The Environmental Evaluation report prepared for the Du Pont-Newport Site identified severalSite-related wetland sampling stations where sufficient biological evidence was present to inferenvironmental impacts that are likely due to metal toxicity. The central portion of the NorthDisposal site drainageway (Stations ASO7, ASO8, and AS09) is currently the mostenvironmentally impacted area within the Newport Site study area. Impacts are possibly dueto most, if not all, of the constituents of concern.

In the Christina River, environmental impact is only suggested by the data sets for StationsRS11 and RS12, which are located along the northern river bank adjacent to the CIBA-GEIGYplant area. In addition to the presence of the two disposal sites, discharges to this portion ofthe Christina River includes three City of Newport stormwater pipes which include industrialoutfalls near the James Street Bridge, permitted CIBA-GEIGY outfalls, along with groundwater



Area of Interest

North DisposalSite andAssociatedWetlands

CIBA-GEIGYPlant OperationsArea

South DisposalSite andAssociatedWetlands

Impact

Environmentaldegradation

Potential fill erosion

Potential humancontact withsubsurface soilsduring futureconstructionactivitiesEnvironmentaldegradation

Future potentialgroundwateringestion

Potential soil erosionand transport intowetlands

ImpactedMedia

Surface waterand sediments

Surface Soil

Soil

Groundwaterand sediments

Groundwater

Surface Soil

Location

Central portion ofnortherndrainagewayNorthern portion ofriverbank

Plant area

Northern riverbank

Old Airport Road

Southern berm

Remedial Goal

Source control

RiverbankstabilityInstitutionalcontrols

EnvironmentalimpactabatementPreventingestion ofimpactedgroundwaterErosion control

The institutional controls identified for the CIBA-GEIGY and the Holly Run Plant areas havebeen or are currently being implemented as discussed in Section 1.6. Therefore, identificationand evaluation of remedial technologies and analysis of alternatives for the plant operationsareas have not been included as part of this document.';

The Christina River has been impacted by non-Site related sources and no consistent patternof contamination has been identified. Therefore, identification of remedial technologies andanalysis of alternatives for this AOI have not been included as part of this document.


SR3I2038


• Greater risk to human health and the environment would result fromimplementation of the remedial action

• Technical impracticability• Equivalent standard of performance• Inconsistent application of State requirements• Fund balancing

A waiver to meeting ARARs at the Newport Site is considered necessary on the basis of greaterrisk to human health and the environment, technical impracticability of source control,performance standards, and fund balancing. These applicable criteria are discussed furtherbelow.

3.1.1 Source Control Considerations

At the Newport Site the fill material containing the constituents of concern (barium, zinc,cadmium, lead, TCE, and PCE) occupies approximately 800,000 cubic yards of source volume.At least one half of this source volume is located in the saturated zone below the water table.In order to implement a source control remediation program, the fill material would have tobe excavated both above and below the water table.

Excavation of the source fill material at the Site is technically impracticable for the followingreasons. This excavation operation would involve operations below the active manufacturingareas of both the CIBA-GEIGY and Holly Run plant's which would disturb activemanufacturing operations. Furthermore, standard engineering practices do not allow forexcavation of fill material below the water table in the saturated zone without massivedewatering activities and potential destruction of adjacent wetlands. Disturbance and mixingof the fill material with groundwater withdrawn during excavating procedures would alsoexacerbate existing groundwater quality conditions and potentially alter groundwater flowpatterns.

The restricted areas of source material that contain the organics of concern (PCE and TCE)have not lead to extensive plume migration in the groundwater system. This limited migration



water quality monitoring during the RI has not demonstrated that a statistically significanj,impact from this discharge exists to the environment.

3.1.3 Extraction Technology Considerations

The rate at which an aquifer can be restored through extraction and treatment is effected byconstituent-soil interactions, the nature of the constituents, and the physical conditions of theSite and constituent plume. For all chemicals present in the groundwater there is anequilibrium between the amount of the chemical that is sorbed to the aquifer material and theamount dissolved in the groundwater. The rate at which the chemical desorbs as a result ofclean water being drawn into the contaminated zone under the influence of pumping will limitthe pumping rate that can effectively remove the contaminants.

Due to the nature of the constituents of concern in the fill material at the Newport Site, thesource areas are composed primarily of chemically stable ores which have constituents with lowsolubilities that have a greater affinity to sorb onto the aquifer soil matrix rather than desorbinto the groundwater. This attenuation phenomenon has been demonstrated in three phasesof the RI groundwater monitoring program at the Site. Groundwater chemistry concentrationcontours over the three phases of the RI demonstrate that there is very limited mobility (i.e.,an equilibrium) of the constituents of concern through the aquifer matrix due to this steady-state chemical phenomena. Where MCL exceedances occur in groundwater they are due to thefill material, or are in areas proximal to the fill material. The RI data suggest there has beenpresence of limited plume migration over the decades since cessation of waste material disposaland inorganic pigments manufacturing operations.

As discussed in the Draft RI Report (WCC, November 1, 1991) the historic pumping of theplant water supply wells WW-11 and WW-13 was apparently responsible for the verticaldownward migration of constituents of concern from the fill material into the underlying water-bearing units. Following cessation of the supply well pumpage period at the plant groundwaterflow patterns returned to .non-pumping conditions which subsequently resulted in constituenthorizontal migration. This consequence of groundwater withdrawal provides a basis fordiscounting the feasibility of groundwater withdrawal technologies for the Columbia and



of constituents would typically include flocculation for the metals and air stripping or carbonadsorption for the organics.

All heavy metals treatment technologies generate a large volume of waste material in the formof sludges or concentrated brines. For groundwater treatment systems involving a small sourcevolume and a short treatment duration, the additional volume of generated wastes via thetreatment process is of rninimal concern. However, at sites where extensive source areas existwhich would require essentially perpetual operation of the treatment systems, a large mass ofwaste would be generated by the treatment process. Any groundwater treatment technologyfor the metals will increase the volume of waste material generated over the lifetime of theremediation program and will require additional stabilization of the waste material hi order forit to be accepted for disposal in a secure landfill. Thus, this remedial approach is notpracticable nor cost-effective for the Newport Site. /

3.1.5 Containment Technology Considerations

Groundwater containment technologies typically include capping (or covering) and placementof physical barriers (such as slurry walls or sheet piling) that sure intended to limit themovement of groundwater. Capping has been employed at the Silt ni the-form of the reduced-permeability soil covers on both the North Disposal and South Disposajxsftes. The combinedeffects of pavement and buildings on both the CIBA-GEIGY and Holly Run Plant OperationsAreas serve as capping structures to limit infiltration and percolation of precipitation. Limitinginfiltration by capping or covering reduces water contact with fill materials which subsequentlyreduces constituent migration.

Capping or covering technologies are potentially applicable to the Site AOIs because they arealready successfully utilized to restrict infiltration and to mitigate potential human risksassociated with dermal contact with fill materials. Capping or covering also currently preventserosional migration of constituents from fill materials.

Physical barrier technologies can limit the movement of groundwater in response to eithernatural or extraction-induced gradients. In order to be effective, however, the barrier must be


AR3I20H


The technical impracticability of a groundwater remediation program at the Newport Siteprovides another basis for invoking a waiver to meet ARARs. The technical and administrativefeasibility of potential groundwater remediation at this Site is dependent upon:

• The ability to construct, operate, and maintain the remedial technologies

• The continued availability of hazardous waste treatment storage and disposalfacilities to properly dispose of treatment residuals and waste minimizationimplications; for example, remedies that generate groundwater treatmentresiduals such as sludges or spent carbon are less favorable than remedies thatdo not

• The ability to monitor the effectiveness of the remedy; for example, the lengthof time that monitoring is required, the frequency of monitoring, and the cost

• The ability to obtain approvals and permits from other agencies; for example,obtaining approval to discharge to a POTW may be more difficult than meetingthe substantive NPDES requirements for discharge to surface waters

Based on this summary of the exhaustive evaluation of Site conditions that has been performedby Du Pont and WCC at this Site and available groundwater remedies, it is evident thatgroundwater extraction remediation at this Site is neither technically-feasible nor practicable.However, it is technically feasible and practicable that natural attenuation, combined withlimited monitoring of groundwater quality, be performexj to a designated time period todemonstrate that long-term risk to the human health and/environment do not develop inaccordance with CERCLA Section 121(d)£2)(S)(ii). This/CERCLA section recognizes thatnatural attenuation is a viable long terrnresponse action fo/Superfund sites when contaminantsare expected to attenuate to health-based levels in a relatively short distance or when there isa narrow strip of land between the discharge stream wher z contaminant levels are not expectedto increase. Natural attenuation may be the most pract cable response in these situations.

FFS Rpt/Du Pont-Newport/88C207<>4X/DPN4 / 3-» \ A ^ _. ^ 12-23-91

AR3I20U6


The use of personal protective clothing by workers on-site during excavation should adequatelyprotect against contact with fill material. Fencing and natural vegetative barriers can be usedto restrict unauthorized access to various areas of the Site. Land use and/or deed restrictionscan be used to legally control how portions of the Site may be used in the future; thereby,preventing disturbance of any other remedial measures taken.

3 2 2 Containment Technologies

Soil containment technologies are employed for purposes similar to those for groundwatercontainment (Section 3.1.5); namely to limit movement of soil particles or soil constituents.Containment technologies for soils include, but are not limited to:

• Capping or covering

• Surface grading

• Erosion and sediment controls

Capping (or covering) technologies were discussed in Section 3.1.5 as they pertain togroundwater containment. These technologies are similarly applicable to soil containment atthe Site because they currently exist at Site AOIs.

Surface grading is typically combined with implementation of erosion and sediment controls orcapping as a surface preparatory step. Grading is usually required to establish suitable slopeor contour configurations prior to implementation of capping or erosion and sediment controls.

Surface grading could be apph'ed to various areas of the Site, including portions of the NorthDisposal site such as the "concrete jungle" and the northern drainageway in preparation forsubsequent capping or sediment control technologies. The embankment berms on portions ofthe South Disposal site would also require surface grading prior to implementation of erosionand sediment control measures.



• Excavation may be applicable to the Ballpark surface soils due to the limitedvolumes of material that need to be removed to achieve the remedial goal(Section 2.4)

3.2.4 Treatment Technologies >

Treatment technologies that could potentially reduce the mobility of constituents of concern inthe Site soils beyond what is apparently being effected by the present natural attenuationmechanisms include:

• Solidification: exsitu• Chemical Fixation: exsitu• Physical Treatment (i.e., soil washing): exsitu or insitu• Immobilization: insitu

Other technologies such as biological treatment or thermal treatment (incineration) areinappropriate due to the mostly inorganic and elemental nature of the primary constituents ofconcern.

Application of any of the above-listed four technologies in an exsitu mode would requireexcavation, processing, and subsequent disposal or replacement of the treated soils. The exsitutechnologies are not technically practicable for the enormous volume of soil materials that couldpotentially be subjected to treatment because:

• Application of exsitu treatment technologies requires excavation which has beenfound neither practicable nor cost-effective (Section 3.2.3)

• Application of exsitu treatment technologies would generate significant quantitiesof additional waste volumes through either the addition of treatment agents (suchas lime or pozzolanic agents) to the excavated soil or through generation ofresidual wastes from treatment of dewatering or washing fluids and is not inkeeping with the NCP principal of waste reduction.


HR3I2050


• Institutional controls for the South Disposal site

• Containment (capping or covering only) for the North Disposal site

• Removal technologies are only carried through for the Ballpark surface soils dueprimarily to the small quantity of soil that would be addressed

• No action alternative, as required by CERCLA


flR3!2052


Alternative BP-2 - Excavate and Consolidation in North Disposal Site

Alternative BP-2 consists of excavating the 1 cubic yard of impacted surface soil andconsolidating the material with the fill materials hi the "concrete jungle" area of the NorthDisposal site. The excavated soil would be loaded in a sealed and covered dump truck forhauling and would be consolidated below the "concrete jungle" cap (Section 4.1.2).Confirmatory testing would be performed at one location in the excavation as a check to seethat cleanup levels of lead were met. The Ballpark excavation would be filled, graded, andreseeded.

4.1.2 North Disposal Site and Associated Wetlands Alternatives

The North Disposal site AOI is located as shown on Figure 1-2 and consists of the disposal areaand wetlands located to the west. Two alternatives have been developed for the North Disposalsite and are presented in the following paragraphs.

Alternative NDS-1 - No Action

The no action alternative for the North Disposal site and associated wetlands would leave theexisting configuration with continued Site maintenance and long-term monitoring.

Alternative NDS-2 - Cover Swale and "Concrete Jungle" - Slope Erosion Protection

This alternative consists of grouting Outfall 002, covering the "concrete jungle" area of theNorth Disposal site, placing slope protection on an area located as shown on Figure 4-1, andreplacing/enhancing wetlands to the west of the North Disposal site. The following paragraphsdescribe the various components of the alternative.

Outfall 002: The existing outfall would be grouted from the manhole located on the northernborder of the North Disposal site to the Christina River outfall. Grouting of the outfall wouldeliminate the potential for contaminant migration to the Christina River through this line.



using the following steps: approximately 6 inches of material (approximately 6 cubic yards)would be removed and placed beneath the cover in the "Concrete Jungle". A 3-inch lift of soilwould be placed in the area removed, followed by a geonet, followed by 3 more inches of soil.The area would then be vegetated with sod, using 'landscape nails" to hold the sod in place.

Wetlands Replacement: Wetlands lost due to capping would be replaced to the southwest ofthe North Disposal site, as shown on Figure 4-3. Rerouting of the existing stormwater drainagechannel would result in approximately one-half acre of wetland loss. This loss would occur asa result of the placement of fill over wetlands that have developed in the drainage channel andalong the existing toe of slope on the south side of the "concrete jungle" in order to achieve a3:1 slope. The wetlands that would be lost are largely areas above tidal elevation that arevegetated with common reed (Phragmites australis). The soil/sediment that supports thiswetland vegetation is non-organic content soil which may reflect disturbance during the periodwhen the North Disposal site was active. The wetland hydrology is established primarilybecause of stormwater drainage to the area from the north.

To compensate for the loss of wetlands described above, an approximately one-half acre areaadjoining the southwestern perimeter of the North Disposal site would be regraded to allow fortidal flooding from the nearby Christina River. This would involve the excavation of existingsoil and sediment within the drainage swale that now carries surface run-off from the north.Most of this area is above an elevation of 5 feet and is thus above the normal limits of hightide. This regrading would result in 80 percent of the area at a base elevation of 3 feet (theapproximate mean tide elevation). The slopes above this base elevation would be graded at3:1, except where the swale enters on the north side. Here the slope would be 5:1 to providefor greater stability and to reduce the potential for erosion.

As shown in the schematic section presented in Figure 4-4, a 6-inch soil cover would be placedover the area to elevation 3 feet. This would require over excavation to elevation 2.5 feet, andreplacement with a organic soil stockpiled during the excavation (if available). Alternatively,soil cover would be brought to the Site from an outside source. Assuming that the soil coverdiscussed above could be salvaged from the Site, the earthwork required to regrade the wetland

FFS Rj>t/Du Pont-Newport/88C207fr4X/DPN4 4-4 12-23-91


Alternative SDS-1 - No Action

The no action alternative for the South Disposal site and associated wetlands would leave theexisting configuration with continued Site maintenance activities.

Alternative SDS-2 - Institutional Controls and Access Road Improvements Restriction

This alternative consists of institutional controls, which would include access restrictions, deedrestrictions, and providing a public water supply for residences along Old Airport Road. AccessRoad improvements include regrading the existing southern berm for Site access, and divertingponded water through a culvert in the southern berm to enhance the wetlands as shown onFigure 4-10. The following paragraphs describe the various components of the remediation.

Fencing/Vegetative Barrier: A portion of the South Disposal site perimeter does not restrictaccess to the AOI. As an institutional control, a combination of fencing and a vegetativebarrier along Basin and Old Airport Roads would be extended around the southern portion ofthe AOI to the western property line. Barriers would not be placed along the western propertyline or the river's edge due to sufficient existing access limitations. An outline of the proposedfencing/vegetative barrier is shown on Figure 4-5. The vegetative barrier would consist of ahedge of Rosa rigosso. a dense bush capable of growing to 4 to 6 feet high. Fencing will beextended from the existing fence to the point shown on Figure 4-10, where the vegetativebarrier would start. The vegetative barrier would extend to a point about 200 feet to the westof the corner of the property, where fencing would be placed to the property corner. A lockinggate would be placed where shown on Figure 4-5 to provide access.

Deed Restrictions: Deed restrictions for the South Disposal site would include restrictions onland and groundwater use.

Public Water Supply: Residences along Old Airport Road would be supplied with public waterfrom the nearest source in order to address unlikely future risks to groundwater.



42 EVALUATION AND COMPARISON OF ALTERNATIVES

42.1 Ballpark

42.1.1 Ballpark Alternatives Evaluation

Table 4-1 presents a summary of the Ballpark alternatives evaluation, based on the sevencriteria listed above. The evaluation for each alternative is briefly discussed below.

Alternative BP-1 - No Action

The no action alternative would not be protective of human health and the environment basedon the Du Pont - EPA action level of 500 ppm for lead in surface soil for non-industrial areas.Potential risks to users would not be reduced. There is no cost associated with this alternative.

Alternative BP-2 - Excavate and Place in North Disposal Site

Alternative BP-2 consists of the following key components:

• Excavate impacted surface soil• Perform confirmatory sampling• Backfill and regrade excavated area• Consolidate impacted surface soil in North Disposal site

Removal of the impacted soil from the Ballpark would be protective of human health and theenvironment by meeting the agreed upon action level for lead in surface soil. The impactsassociated with Alternative BP-2 would be minimal. The risks to users of non-industrial areaswould be greatly reduced, and the potential mobility of the soil would be reduced by placingthe soil beneath the cover in the North Disposal site. The estimated capital and O&M costsfor alternative BP-2 are itemized in Table A-l and total to approximately $7,000. Appendix Asummarizes the assumptions used for the cost estimates.



• Install a soil cover on the "concrete jungle," sunfish pond," and existing swale• Install slope erosion protection on the area shown on Figure 4-1• Monitor groundwater and surface water• Replace/enhance wetlands

The installation of a soil cover would reduce the potential adverse environmental impactsassociated with sediments in the existing swale and adjacent drainage areas. Installation ofslope protection would reduce environmental impacts associated exposed fill materials on theriverbank. Minimal to moderate short-term impacts associated with construction would bemitigated using standard health and safety and construction erosion control practices. Long-term effectiveness would continue with proper maintenance. The ARAR concerning loss ofwetlands would be complied with by the replacement/enhancement of wetlands to the west ofthe North Disposal site. Overall protection of human health and the environment would beachieved.

The estimated capital and O&M present worth for alternative NDS-2 is $330,000. thecomponents of the alternative are itemized in Table A-2 and O&M present worth costs areshown on Table A-3. Appendix A summarizes the assumptions used for the cost estimates.

4222 North Disposal Site Alternatives Comparison

Table 4-2 presents a comparison of the two alternatives for the North Disposal site. The twoalternatives are as follows: no-action (NDS-1) and cover swale and "concrete jungle" - slopeerosion protection (NDS-2).

Alternative NDS-2 would substantially reduce potential adverse environmental impactsassociated with the sediments in the swale and adjacent drainage areas and exposed fillmaterials on the riverbank, while the no-action alternative would allow these impacts to persist.Alternative NDS-2 would provide an effective long-term remediation of the these areas whencompared to the no-action alternative. The no-action alternative would not provide anyreduction in mobility of impacted sediments or exposed fill materials; alternative NDS-2 wouldsubstantially reduce the their mobility. Both alternatives comply with the ARAR concerning



Fencing/vegetative barrier installation, culvert installation, and berm improvements would haveminimal short-term impacts during construction and would be implemented using standardconstruction practices and appropriate health and safety measures. The potential for exposureto fill materials in the South Disposal site would be reduced because of the access restrictions.ARARs pertaining to wetlands loss would be met by mitigating erosion of the berm andwetlands enhancement. Overall protection of human health would be achieved by reducing thepotential for dermal contact with the South Disposal site impacted soils. Potential adverseenvironmental impacts would be mitigated by berm improvements and culvert construction,which would reduce erosion and enhance the wetlands value by reducing increasing commonreed overgrowth.

The estimated total present worth of alternative SDS-2 is $134,000. The estimated capital andO&M costs for alternative SDS-2 are itemized in Table A-4 and O&M present worth costs areshown on Table A-5. Appendix A summarizes the assumptions used for the cost estimates.

42.32 South Disposal Site Alternatives Comparison

Table 4-3 presents a comparison of the two alternatives for the South Disposal site AOI. Thetwo alternatives are as follows: no action (SDS-1) and fencing/vegetative barrier-regrade/surface access road-berm erosion protection (SDS-2).

Alternative SDS-2 would reduce potential risks associated with trespass, while the no-actionalternative would continue to allow trespass. The adverse environmental impact associated withberm erosion would continue, while alternative SDS-2 would address this impact. The no-actionalternative would not comply with the ARAR concerning loss of wetlands; alternative SDS-2would prevent loss of and enhance wetlands. Alternative SDS-2 would be more protective ofhuman health and the environment than the no-action by restricting access and bermimprovements.



The North Disposal site AOI has existing or potential environmental impactsassociated with the swale and associated drainageways, the fill material exposedon a small area of the riverbank, and exposed rubble in the "concrete jungle." OFthe two alternative developed (no action (NDS-1) and Cover-Erosion Protection(NDS-2)), alternative NDS-2 meets the remedial goal established for this AOI.

The South Disposal site has existing potential environmental impacts associatedwith berm erosion and loss of wetlands. Of the two alternatives developed (noaction (SDS-1) and Access Restrictions-Berm Erosion Control (SDS-2)),alternative SDS-2 meets the remedial goals established for this AOI,


•AR3I2066

Tables

/JR3I2067

TABLE 1-1

HYDROSTRATIGRAPHIC UNITSFOCUSED FEASIBILITY STUDY

DU PONT-NEWPORT SITENEWPORT, DELAWARE

Depth Range Unitto Top of Range of

Unit _____Lithologic Appearance_____ Unit (ft) Thickness (ft)

IF Fill/Other Quaternary Zone; (Includes 0 2' - 30.5'Fill Material, Quaternary depositsyounger than Columbia Formation)Fill material of various grain-sizesand color underlain by brown toorange brown sands and clays.This unit often contains agray-black organic clay at its base.

IA Columbia Formation (A). (Columbia 10' - 39' 0' - 20.5'Formation; Pleistocene) yellow brownto orange sands and clays, gradingcoarser with depth.

II Semi-Confining Unit. (Top of Potomac 17' - 42' 9' - 40'Formation; Cretaceous) Top markedby the first appearance of white-graysand or reddish to orange sandy clays.Appears to be an effective semi-confining unit separating Unit Iand Unit IIIA.

IIIA Intermediate Zone (Bl. Clayey sand 32' - 55' 13' - 50'unit. Clayey sands in the uppersection grade to a more clayey unitwith depth. Sands range from fine tomedium grained with varying claycontent. Color ranges from redto orange to yellow.

IIIB Semi-Confining Unit. This unit is 51' - 105' 1.5' - 27'very similar to IIIA in color andshows interfingering of beds exceptthat the clay content increasessignificantly in the lower portionof this unit. The top of this unitis marked by a violet-red, manganese-stained clay. Appears to be aneffective semi-confining unitseparating Units IIIA and IV.

FFS Rpt/Du Pont-Newport/88C2076-4X/DPN4 12-23-91

TABLE 1-1

HYDROSTRATIGRAPHIC UNITSFOCUSED FEASIBILITY STUDY

DU PONT-NEWPORT SITENEWPORT, DELAWARE

(continued)

Depth Range Unitto Top of Range of

Unit _____Litholocfic Appearance_____ Unit Thickness

IV Deep Zone (C). Usually contains a white 58' - 125' 3.5' - 30and light gray to orange mediumclayey sand, up to ten feet inthickness overlying the bedrock. Thisunit may contain red dense clays and/orblack organic-rich layers generallyless than 18-inches thick.

V Decomposed Bedrock. Olive green, 50' - 140' 40+friable, weathered schist and gneissoccasionally overlain by off-whiteclay. Probable low permeability;probably acts as a lower confiningunit.

FFS Rpt/Du Pont-Newport/88C2076-4X/DPN4 12-23-

^312069

TABLE 2-1

NEWPORT SITE GROUNDWATER ARARSDU PONT - NEWPORT SITENEWPORT, DELAWARE

Constituent

BariumCadmium

LeadPCETCE

Chromium

MCL

10005

(currently, 50) 10*(currently, none) 5#

5100

These MCL concentrations are shown in micrograms/liter (ug/1).

* Technology based effective November 2, 1992# Effective July 30, 1992

Federal Register Vol. 56, No. 20, My 30, 1991.

FFSRpt/Du Pont-Newport/88C2076-4X/DPN4 12-23-91

3R3I207Q

TABLE 2-2

WATER QUALITY CRITERIAFOR THE PROTECTION OF FRESHWATER AQUATIC LIFE (ug/1)

Parameter

AlkalinityAluminumAntimonyArsenic +5Arsenic +3BerylliumCadmiumChromium +6Chromium +3CopperCyanideIronLeadMercuryNickelSeleniumSilverThalliumZinc

USEPA |

Acute

9,000*850*360130*3.9+16

1,700+18+

82+2.4

1400+

2804.1 +

1,400*120+

Chronic

20,000

1,600*48*1905.3*1.1 +11

210+12+1,0001,0003.2+0.012

160

360.1240*110+

DNR^ " ™ *'*™*™**™ ^ ^ ™'**"**™*M*~

Acute

750

360

3.9+16

1,700+18+22

82+2.41400+

20

4.1+ '

120+

EC

Chronic

87

190

1.1 +11

210+12+5.2**10003.2+0.012160+5

0.12

110+Notes: * Lowest Observed Effect Level.

** Free cyanide at lowest pH occurring in receiving water.+ Hardness Dependent; value listed is based on 100 mg/1 as CaC03;

measured values in wetlands near the North and South Disposal sitesrange from 104 to 183 mg/1 CaCO3.

Source: U.S. EPA Quality Criteria for Water 1986; updated 1987 (Criteria for theProtection of Freshwater Life).

State of Delaware Surface Water Quality Standards, As Amended February2, 1990 (Criteria for the Protection of Freshwater Aquatic Life).

FFS Rpt/Du Pont-Newport/88C2076-4X/DPN4

w

toH

1S§uH

U HH w

P! W p»g ti 25 rt* ?•

CO ^M S f^

»2 E !••!S a °o » „a Sii«• £Z QJH a cH2«CQ Drtj Q•Bft

PMOX31to

1

p

HEHH

CO

0u

HUEH

CU

TJ(0j

g3•H6O

^

|•H6"o(0U

g•H

(0

*0)coCSI

10)4JS

1Oo010)0)cI. .o(00)«

10"H(0H

IS•o0)n)•Hoo0101<•8C(0CO

X

X

rHrH-Hfa

,

X

X

X

X

BrHiHntCO

^

X

0)4Jm•H•o0)M

0)cH

,

tt0)Q)Q

^

(00)£•4rtj01Co•H4J(00)81c(0

04

SHOH

01CQHO

X

X

rHrH•rHfa

9

X

X

,x

X

X

grHrH(0

CO

^

X

X

0)4J(0•H•o0)WQ)cH

B

X

X

X

Ql

a)Q

^

01C10rH

0)

TJ

510•H0O0101rtj

c10

COaCO

X

X

X

X

X

HrH•Hfa

9

X

X

X

X

X

§rHH(0

CO

.

X

X

X

a)<0•H

a)Ma)H

,

0)Q

.

(00)h1 4

0)£o•H4J100)ao4JC(0rHPLl

CJ3«HrHOIB

X

X

HrH•HEM

.

X

X

8rHrH(0.CCO

.

X

0).p10•HTJ0)M0)-PcH

.

X

X

X

Q*a)Q

.

.coH4J

'ftO010)

<MH

H

0)H

10EH0)0)CO

HR3I2072

TABLE 2-4

SUMMARY OF SURFACE WATER QUALITY CRITERIA EXCEEDANCESDU PONT - NEWPORT SITENEWPORT, DELAWARE

Area of Interest/Location

North Disposal Site• Drainageway

South Disposal Site• Pond• Wetlands

Copper

X

CONSTD

Lead

X

X

rUENT^ "" -- — — •-— — .

Mercury

X

X

Zinc

X

FFSRpt/Du Pont-Newport/88C2076-4X/DPN4 12-23-91

SR3I2073

33CO

roo

•

«•)

S

1

§

ex-si tu -tn-SItu -

II

f1

II

- Isplssamts• Hot luplen

S2

•

*s

*

fJ!

I•

S

•

SW

S

i

:nI3•os

ss

If1'??n wss- Isplsoenta

- dot llt>ls>

SS

4

*

S

X

*

5

I

1

5

In-sltu trastnent not proventechnology

1

f2S

1

S

M M

SS

11— s*tt «#

SS

si|I*•

1

*

?

1•

*

Ex-situ trastusnt Mould isneratlarso volunes of addltlonsl unMterfals «*lch Is contrary toIntent of Htf

•

g

f

§

—

tlaplaiMntabl

aeS-

t

1tr•

s

•I

n

IHiI•o5

1

S

i

3E

q.

fs

5

!Ft

S

2S1S

g

s

s

Isillamitab!

*

O

\JT

*

Extraction ineffective and{•practicable due to physlco-cheislcal equilibria Issues

•

1

r5

§

5s

H

i

fj"

,iIf

2

-

!jf

nis2S

sl||

*

.J

"

?•<|l

s

ijss

"§

.9X g

Iskpteawntabl

J

J

S

II

If

I

Physical bsrrlers not effectivepracticable due to lack of unlfloner penaeablllty subsurface i

Js?

§

fs

L

p?

I1

*

Can control unauthorized acctss

•

IIfT

I

n5s«im

s

lifilsMntabl

2

B

1

a

Can control potential risks thrheslth and safety plans

i

*

fa

§

I1Mtl• i

f,5*

II

s

Cannot Mitigate surface Materquality problem In northern di

*

1s11i

0=

s

,1-~5§^3

If

• 5

InpteHMitabl

¥

1i

s

HS

flj!

f

IM

•H

1

1

f

!T

s

T*Effectiv

It• am 7"^

-

I

x

STS

S

J-ifs?»|fM

t*

=0CO

rooen

wr*•fi

2

B3

f~

S8i8-•*

<

i•a

!

1

o

In-sltu treatawnt not proven |

X

s

Io

5

Ineffect

S

s1

5"

,"fl

S

S

5

dot practicable due to large volues 1

of additions! nsste generated by 1

•xltu treateant 1

is-4

|

|

"

r1

Only Ex-Effect 1

S

i

I£

• j~11• s•<

s>ell quantity alloue practicability 1for lallpsrk only

1

|

[

f

f

Ir

fm|.

S

*

r

s

1j.g

n•

\

S

[?

s[

*

,xJ.

5

*

I

5

Incrasses short-tane risk 1

*

if

I1

|

s^*

a,

;

•

o

dot practicable due to larger voluw 1of additional Hnte genaratid by

1required deueterlng

1

|

-

|

&ic*

r

"

Effect!

{

i

i

J

1

S

twll quantity allow effectlvlty j

for lallpsrk only 1

8

jj

i

fa*

f

if

•

o

ij£•I

o

oBA-GE1GY

2

"Only CsnEffect!

i

f

IX

*

T ;1

It

*

o1j:ij.?

s

"oe« not aiReMdlal

i

2

|

S-

5

Capping can effectively Isolate 1

constituents froa the envrlonaent 1

1

1

1

2

X

£

5

Can control unauthorized Kent

1

I

Srt

f

n

13ti

"

|j

st>les>ntsb

2

X1**

i

2

Can control potential Make through 1

health and ssfaty plana 1

3as

*

oes not aiReMdial

,'»"l

4

i

tI

•

118 "1!

S"

{

i5

1

I

fe

S

rf*'

oes not *ReMdlal

?'•i

if-

i

j

I

s

"sP

j"§1Ini

O

If

s!psrk, MISIGV Plant

'"5

oes not wReMdlal

>S-

•1

I

I

|

•c

II«!i!ti

i

3i

I1

ifsi

!1

ri-.i

H!

•

CO

roCD

cn

S

* * -1\a § *t it {

: J Ii "

§

m

ifs

9

1«•*

3*

*itn"

<•*

5

2

R5

m

ifs

?!Ig.

f

8-

S

Ift

**

•

i

m

ifi

s«I?

,K»

|?ft•I

•

fff||

Ijllgl-fr*•2 o R

ill

rI3-

m

ifs

I.7

.?•is1*

'

(Mil quantity

on-slts or offgallperk soils

II-

Hss?l

•

»

_

?

?[

8-•

sx8-

?

r.1

5

I"I

I

1

I

1

m

N• ss

M

I1 .

?ssi1

li-l

sf&

1

11

TSPSS?/**'£!>*;*SS"»*gW'.- -.-JXB9- Bs SM1;.

I

ft

1 •u] E"

jl^ p/ <j 5<

§1^1^ O g

*\ •? O

EVALUATION AN

BALLF

DUI

Alternative C

omparison

.S

Lxcavate & Pl

ace

th Disposal

site

U4 c

a

BP-l:NoActio

SS15§•A

15W

1i3

»•*1 s

Alternative BP— 2

would effectively r

emedi

the ballpark wh

ile Alternative BP-2 wo

uld

effectively r

educe exposure

i

•3

during construction

ort o

f small vo

lu me

iMinimal impact

HandlingAranspi

1 1

<9e «

impact du

ring

constructiol

ientia

l user c

ontact wi

th so

£ &1 1

fc

en(uC

.11S«5

i

"O

Alternative BP— 2

would reduce re

ceptor

contact and migration while no longterm

effectiveness or permanence would be

reali

with Al

ternative BP-1

i

aif

i/els would be remov

I would

require long

Elevated le

ad le

'Disposal in

NDS

commitment

1 1

'3a

restriction on co

ntact with

gI

gB

gCMggj?O-ik•2<C

1S

(4-4

VM:

.f3

nITS 'S

Alternative BP-2 wo

uld reduce

mobility w

Alternative BP— 1

would not provide a redi

i

1.§*• •

toxici

ty or vo

lume

ol

ibilit

y

No re

duction in

soil

Reduction in me

1 1

Both

alternatives ar

e easily im

plemented

i

1

rd construction pr

aclil

able

Requires

standai

Vendors are aw

1 1

reduction

£i

g.3

185*H3•g1(•&*

t•%

!?*8c

Reductio:

sily implemented

COUJ1

fca11"E.

ca. e3 —

Alternative BP-2 wo

uld comply

with ag

ree

action

level w

hile Al

ternative BP-1 wo

uld

violation

I

"31

greed upon

action le

—industrial a

reas

Complies

with aj

500 ppm for non

1

•aS

3

n -compliance

with ag

reed

ion le

vels

1 1i

/535543

14)

1

r*1a.PQ

Alternative BP-2 pr

ovides pr

otection wi

thsound handling pr

actices while Alternative

not p

rovide pr

otection

I

1~

osure by us

ers to le

appm eliminated

Potential forexp

greater than 50

0

1

1

|ura

ntinued potential userconi

8i

ieo•SW°9_*"oSflj£

3K"Se

Protectio

i i iis

2 f

•Alternative BP- 1 would not be acceptable

the s

tate wh

ile Alternative BP-2 wo

uld be

i

23

tential r

eceptor r

iske alternative

Reduction ofpo

make

this a

viabl

1

Jg JB.2 oC e;

tentia

l receptor ris

k would

uced

and would therefore i

eptable

£ i yi

<a

SCL.U

1«ROT

iOo 2M ...

Alternative BP- 1 would not be

acceptable

the c

ommunity

while Alternative BP-2woi

viable

I

2'S

tentia

l receptor r

iske alternative

Reduction ofpo

make

this a

viabl

1

i io Se c

tentia

l receptor ris

k would

uced

and would therefore i

eptable

<2 1 «i

w

i

•f9n|c

M

A minimal cost is

associated with implemen

Alternative BP-2

I

ft"

-

JSC1i8*rt

*7.&

nAlternative C

ompar

DSN &

§

z

uI

31^ - >* - so c - lii — ., s» a -3 •« E c^Sy tw

o °5§2 «S05 go«M S»':t2

O.1 .

I

I

6 e

i

reduction

um

iI

•goIB•8a;

§ -sIIi" ^i §Mifif*i 1Ts

mplemented

sO9

I

•§i

S3M

•s

e3 .•= a r: co « u v ^ n u v f

J5« T3fr"u

2

JBo 3i i2 N8-ci

be -DS

DS-

would not

lternative N

ive N while A

l

uH

?> w3 Qv zJj gi 'f2 |3

r, JB

S1§ti ii 1 «u " S

a« n u -5 3£ urn

uo

S

I)

C4onw\

I2

SI

1

I *S *••3 o

ll•S bi!Hll- "8 jj•S I ?•a a BII !<2 £ \

te

i

g

E4-3

\RISON OF ALTERNATE

E AREA OF INTEREST

•WPORTSITE

i— 3 Pi H S^ S 55H8^§go£Z ja^ >— '

slsiDO,-J co>W

Altern

ative Co

mparison

_ i23. ea§C

to

SDS-2:

Regrade A

ccess I

Fence/Enhance Wel

§1o

ico

C0"C.•§ka4

01J

1u3

"8f —

1 short te

rm im

pacts a

re as

sociated wi

ltiv

e SDS— 2

and no

impacts a

re as

soct

ernative SDS-1

litau

0

-Minimal

impact du

ring co

nstructi

-Potential co

ntact d

uring culvert i

construction

00

•o

:ontact w

ith s

oils

is & trespasses

5

llII1

*

CA$G.§8w

1ico&

1 23 9

tive SDS— 2 would provide a

n improvt

nds value w

hile Al

ternative SDS-1 wi

mental to

the wetlands

S 3 1| I 'i '"

3.

-Potential fo

r trespass re

duced

-Erosion

of berm

controlled wi

th <

maintenance

-Wetlands enhancement

llg rtO >il

tion o

n potential

1 reduction

in we

)

y uMia84s»*isOu4$

8§SSSWg

S!

H

iction wo

uld be realized by

either of

ttliv

es

111

-No reduction

ts1£i

i1gj>*rsif*-*&11(4-4O

|

1

,

tive SDS— 2

would not

require unusua

ss for i

mplementation over

that of

tive SDS-1

§ i "

III

85

-Requires standard construction p

- Vendors are available

ilemented

Q<St1

S

'$

1

"S.

•0•3

tive SDS-2

would comply

with th

es ARAR wh

ile Alternative SDS-1 wo

IIII

vS

-Compliance with we

tlands ARAI

11n

ipliance wi

th we

ll

g

11

D§•™3S5w

.2

}

tive SDS-2

would provide g

reater

on th

an Al

ternative SDS—

1

H1

£ 31 "f

-Reduce erosion & enhance wetla

-Reduce potential human contact

•a00so/iental i

mpact e

xist

ith so

il du

ring

ins

s continues

a s «>I I IIdi i

ie1tuJs»

•S8SSSy— iO

|

1

_uo is

tive SDS-1

would

not be ac

ceptable t

: while A

lternative SDS-2

would be v

i i1 1ingsI sS -a•a i

-Reduction

of po

tential r

eceptor 2

risk w

ould make

this a

viable

alte:

IIII4) M

i ireceptor an

d envi

be re

duced and v

eptable

| § S TJ «

S 1 -£ 1 §i

ep-8PCO

JSo 2

tive SDS-1

would

not be ac

ceptable t

munity

while Alternative SDS-2 wo

u

S o uu u "35 u «1

§

1I Su *5•a |

-Reduction

of po

tential r

eceptor 2

risk would make thi

s a vi

able

altei

11

f |

receptor an

d envi

be reduced and M

eptable

i 1 -1 1 i1 1 i

Q

1ex8^|

R/*S I•«* i

isocia

ted wi

th Al

ternative SDS-2 arc

te

CO Q

11|

35

o

J3

1

S"5

1

I

^

Figures

/SR3I2080

DUPONT NEWPORTSITE AREA

MAP SOURCE:USGS MAP7.5 MNURE SERES (TOPOGRAPHIC)WIMINGTON SOUTH, DELAWARENEW JERSEY QUADRANGLEPHOTOREV1SED1987

SCALE

REGIONAL LOCATION PLANDUPONT-NEWPORT SITENEWPORT. DELAWARE

Woodwtvti-Ctyti* Conwttmto____ Conwlthcj EhgkmrK Ctolegtite ond Env*oom*ntd SotantM*

2000 4000 FT ** N<« 88C2078-4XOrann bye j.c.

Drewhfl No. 807WT12CtMolMd b)«

Sad*AS NOTED

Dot* 12/90/M

FIGURE 1-1

cor\sOCO

S3HVP

UNSCANNED ITEM(S)

ONE OR MORE OF THE FOLLOWING ITEMS MAY BE ASSOCIATEDWITH THIS DOCUMENT:

PHOTOGRAPHSDRAWINGS

OVERSIZED MAPSROLLED MAPS

PLEASE CONTACT THE CERCLA RECORDS CENTER TO VIEW THEITEM(S)

From:To: RSTURGEODate: Friday, January 10, 1992 10:13 amSubject: DuPont Newport FFS

I have a few comments on the document.

£.. Pg. 2-4. The description of the conservatism of the RfD forcobalt is overstated. The value we allowed DuPont to use was tentimes less stringent than recommended by ECAO, and is fullyconsistent with EPA's risk assessment guidance fornon-carcinogens. While DuPont certainly has a right to discussthe uncertainties associated with this number (and they areconsiderable) they should do so objectively.

A year or so ago the technical support team for this site satthrough a half-day seminar on in situ stabilization of dissolvedmetals. I presumed the purpose of the seminar was to acquaint uswith this technology because DuPont intended to use it toremediate the Newport site. However, the FFS hardly mentions thesubject, proposing instead to cap the north and placeinstitutional controls in the south. (This is continued under #3below.)

3. Neither the FFS nor the RI adequately explains why thecontaminated groundwater has not migrated farther offsite; theymerely observe that it remains in a contained mass. However, adetailed mechanism of precipitation of metals by naturallyoccurring anions was proposed at that half-day seminar last year.Why are the details of this mechanism not described in the RI andFFS?

This brings me to the issue which continues to bother me aboutthis site: The RI documents that off-site movement of metals viagroundwater has been much less than might be expected. However,whatever it is that has prevented metals migration is notdescribed. Therefore, EPA has no assurance that the attenuationis permanent. If the attenuation is not permanent, CERCLA is notsatisfied.

In summary, I would like to see the technical contant of thatgroundwater seminar, regarding both treatment technology andnatural attenuation, added to the site-related documents.

CC: NCICHOWI, EJOHNSON

UNITED STATES ENVIRONMENTAL PROTECTION AGENCYREGION III

841 Chestnut BuikJingPhiladelphia, Pennsylvania 19107

SUBJECT: Review of Focused Feasibility Study DATE: 1-15-92for Du Pont-Newport Site inNewport, DE

FROM: Nancy L. Cichowicz,Technical Support Section (3HW15)

TO: Randy Sturgeon, RPMDE/MD Remedial Section (3HW25)

A review of the above-mentioned report that was prepared byWoodward-Clyde Consultants and dated December 23, 1991 has beencompleted. The following comments are offered for yourconsideration.

Section 3.1 Ground-Water Pre-Screening

l. On page 3-2, it appears that Du Pont has included "fundbalancing" as a reason why EPA should consider an ARAR waiver forground water at the site as if it means "costliness." This isclearly not the intent of fund balancing in CERCLA.

2. Page 3-5 refers to EPA's "recently acknowledged concept" thatground-water pump and treat systems are less effective thanpreviously thought and may not ever achieve- cleanup goals. Thisinterpretation of EPA's "concept" implies t ground-waterextraction systems are therefore less desii -a, which is not thecase. Rather, OSWER is attempting to clari previousrecommendations regarding ground-water remediation based on agrowing understanding of sites where these actions are inprogress. Recent evaluation of operating ground-water extractionsystems has indicated that certain hydrogeologic and contaminantcharacteristics appear to impede the ability of currentlyavailable technologies to restore ground water to its beneficialuses throughout a contaminated area. Specifically addressingDNAPL contamination, a problem that appears more widespread thanpreviously realized, OSWER has stated that restoration tobeneficial uses of portions of a contaminated aquifer may not betechnically practicable and that alternate goals, includingcontainment and shrinking of the contaminated area, may need tobe established. Hence, the intent of OSWER's proposed directive(in draft) will not be to diminish the use of, or criticize theeffectiveness of, extraction systems for remediating contaminated

ground water, but rather to promote a consistent approach toremediation when dealing with certain complex situations and toclarify expectations regarding remediation goals.

Section 3.2 Soil Technology Pre-Screening

1. Page 3-13 states that in situ technologies for ground-watertreatment were discussed in Section 3.1.4, yet no discussion iscontained in this section about in situ technologies. Also,Table 3-1 shows that in situ treatment technologies for groundwater are ineffective, not implementable, not practicable, andnot proven, but no information is provided to support theseconclusions. Recall that in situ stabilization of dissolvedmetals was the topic of a half-day seminar that Du Pont presentedto EPA in February 1991. The technology was presented then asproven, practicable, and implementable. Please provide thedetails of this technology.

c: R. SmithE. Johnson

AR3I2086

UNSCANNED ITEM(S)


PHOTOGRAPHSDRAWINGS



/ _r1

/ HOME | f 0_L. >av .1,

r~ —— ——— — _ _ ___ _

1

HOME

h " " APPROX.PROPERTY

LINE

CyHOME f\_

/ ^

HOME HOME>- __„ _.,„ ,_., /•<,g

\i^ ^*TELEPHONE ". .? ' :-POLE OP&L VALVE :W,BF-7 752 =:VAL (V

P" #42192 "/ N7 /

8F~11aatJ

[ hBF~8x» BFt^ . .» * • " ™ ™ It

X——>-~X FOOT PATH -^ * * * aARRICADE^VF(1 . __ » 4 • .* * BF-10 • i >^——— -——^Vj . ** „. BF

WINDSOR ^BARRICAD^ .• * *

/ ,BF-6

HOME

1

—— X ———— X— —— X ————— X ———— X ———— X ———— X-

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. BF-3 T fS

BACKSTOP' M.BF-5 ^

————— X ———— -Sf- ——— X ————— X ————— X ————— X ————— X ————— X ———————

2X

~12 ST.

-9Ul

DEADEND.

STREET

RAILROAD TRACKS1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 l-f 1 -1 M ' • i • ' ' ' • ' i ' ' i ••• i . . . . . . . . . . L^

LEGEND:

- - SOIL SAMPLE LOCATION (2-21-9

• SOIL SAMPLE LOCATION (4-8-91

R«v. No. Dot* Tjp« of R«vWon1 4/17/91 ADD P*iAanf fl LOCATIONS

BALLPARKSAMPLE LOCATION PLAN

0 DUPONT - NEWPORTNEWPORT, DELAWARE

^V^^QMalvWMU vM si 0 svtM BHBBail

•fe* Na: 8802079-4 DrawtH No- 80784510 Dot*Dram by: TJ». Ch*ok«d by: U.K.

———————— Sod. , , , , , , F I C————— 6 WFEET

nt»mid Sdtntitt*08/06/91

JURE 1-6

AR3I2089

NORTHOSAL

CONCEPTUAL PLAI* - REPLACEMENT WETLANDSFOCUSED FEASIBILITY STUDYDUPONT - NEWORT SITENEWORT, DELAWARE

Woodward-Civet*CenauHha EhdMsni amimn mi BuiennMnUI **n«rt

8

345.tinIS3S

ELEVATION - FT.(MSL)

ELEVATION - FT.(MSL)

UNSCANNED ITEM(S)


PHOTOGRAPHSDRAWINGS



Appendix A

flR3i2095

Appendix ACost Assumptions

Ballpark AOI Alternatives

• Excavation of 1 cubic yard of material from an area of approximately 14 squarefeet would be performed with a front end loader of 0.5 cubic yard capacity. It isassumed that 1 day would be necessary to setup, excavate, and shutdown. Thecost includes an equipment operator and a foreman.

r \• Confirmatory testing (a TCLP analysis) of 1 sample from the excavated area

would be performed to demonstrate/ that lead cleanup levels were met,

• Disposal of contaminated soil in the "concrete jungle" area of the North Disposalsite would be performed by a 12 ton capacity dump truck.

• Clean fill would be placed and compacted with a hand tamp in the excavatedarea.

• Sod would be placed over the backfill to cover the 14 square foot area.

• Charges for mobilization and demobilization include the front end loader.

• Costs were generated based on 1991 dollars.

88C4076-4X/ app A A-I ^3/2096

South Disposal site AOI Alternatives

• Regrading of the existing access road (1300 feet) and an extension of the accessroad (1420 feet) would be performed with a grader.

• Geojute or an equivalent product would be placed on the extended access roadsideslopes (1420 feet) for erosion protection.

• Gravel would be placed on the existing and extended access road surface (2720feet) to a thickness of approximately 1 foot.

• Yearly maintenance of the access road was estimated as the cost of replacementtwice during the 30 year design life.

• Vegetative barrier, Rosa rigosso. would be planted at the existing berm along theroad frontage of Old Airport Road for a length of 1060 feet. It is assumed that800 plants would be necessary and that once planted, the Rosa rigosso would notrequire further maintenance. Installation is included in the cost of the plant.

• Fencing 6 foot high with 3 strands of barbed wire would be placed adjacent to theexisting fence along Basin Road for a length of 720 feet and from the westernproperty line along Old Airport Road to the east for a length of 200 feet. A gatewould be placed at the entrance to the existing access road on Old Airport Road.It is assumed that the fence would require painting once every 5 years.

• Placement of a culvert at the existing pond outlet assummed a reinforced, 48 inchdiameter class 3 culvert. The extent of the culvert was assumed to be 80 feet.

• Charges for mobilization and demobilization include the grader, equipment toplace the erosion control product, the gravel, and the culvert, and fenceinstallation equipment.

• Costs were generated based on 1991 dollars.

88C4076 X/ ipp A A'2 AR3I2097

North Disposal site AOI Alternatives

• Clearing and grubbing was assumed to consist of light trees in the 1.4 acres of the, "concrete jungle" and "sunfish pond."

• Covering of the "concrete jungle" and the "sunfishpond" was assumed to consistof regrading the 1.4 acre area with a grader, placement and compaction of a lowpermeability fill material to a thickness of 18 inches, placement of a cover soil toa thickness of 6 inches, and hydroseeding to revegetate the area.

• Swale covering was assumed to consist of equivalent components used in thecapping of the "concrete jungle" and "sunfish pond." A concrete section ofapproximately 12 feet in length was assumed to cross the existing access road, butwas not costed as the cost of a concrete veneer was assumed to be equivalent tothat of the cover soil and hydroseeding used in the remaining portion of theswale.

• Maintenance costs for the "concrete jungle," "sunfish pond," and swale wouldconsist of grass cutting 5 times a year at a rate of $100 per acre over the 1.65acre area.

• An energy dissipation apron was assumed to cover a 450 square foot area at theentrance of the swale to the southwestern wetlands. Concrete filled fabric bagsof 1 cubic yard capacity were costed for the apron.

• Wetlands enhancement was assumed to consist of regrading the 0.8 acre area witha grader, excavation of 3,100 cubic yards of material to elevation 3 feet,revegetation of the tidal wetlands (0.6 acres) with emergent wetlands species, andrevegetation of the southern slope (0.2 acres) with trees and shrubs.

• Protection of the Christina River sideslope for Alternative NDS-2 was assumedto consist of a geogrid reinforced 6 inch cover soil. A stapled sod layer was.assumed to be placed over the cover soil. The extent of revegetation was

88C4076 X/ .pp A A-3 A R 3 I 2 0 9 8

assumed to cover an area of 310 square feet along the northeast portion of thesideslope.

Grouting of outfall 002 was costed based on grouting a 24 inch diameter pipeover a 150 foot length.

Groundwater monitoring would continue to be performed at 1 upgradient well(Sht-2), 3 downgradient wells (MW-33A, SM-4, and DM-6), and 1 well on top ofthe North Disposal site (SM-3). Annual monitoring and analytical analyses weresumed and costed as $700 per well.

Charges for mobilization and demobilization include a grader, clearing andgrubbing equipment, standard excavation equipment, and construction equipmentto place the cover.

Costs were generated based on 1991 dollars.

88C4076-4X/ ipp A A-4 AR3I2Q99

TABLE A- 1ALTERNATIVE BALLPARK - 2

EXCAVATE AND PLACE IN "CONCRETE JUNGLE"PRELIMINARY COST ESTIMATE

DUPONT NEWPORT SITE

Item Description Cost Basis

Excavate Soil (1 cy - 1 day) $1000/day

Transport Soil to NDS via Dump Truck (1 cy - 1 day) $305/day

Confirmatory Testing - TCLP (1 sample) $1 ,200/test

Backfill Ballpark and Hand Tamp (1 cy) $27/cy

Restore Vegetation (Sod — 14sf) $0.50/sf

Mobilization & Demobilization lump sum

TAtafnfiiirai -i::lota!:pEej$&Ps;|:.^

Health and Safety (10% of DC)

Engineering Costs (20% of DC)

Contractor Overhead and Profit (15% of DC)

Contingency (15%)

Note: Costs were generated based on 1991 dollars

Cost

$1,000

$305

$1,200

$220

$7

$1,000

!i;il$3;7QO

$400

$700

$600

iii!$5 do;$800

1; $6,000

aR3l2IOO

TABLE A-2ALTERNATIVE NORTH DISPOSAL SITE - 2 1REGRADE & COVER CONCRETE JUNGLE |B

ENHANCE WETLANDS AREA - CONTROL STORMWATER IPREVEGETATE RIVER'S EDGE SIDESLOPE AREA

PRELIMINARY COST ESTIMATEDUPONT NEWPORT SITE

Item Description Cost Basis Cost

Clearing and GrubbingConcrete Jungle/Sunfish Pond (1 .4 acres)

Subtotal ' ••• '. ..':••••""• '\::vr::;:.r;.::HE;:

Concrete Jungle/Sunfish Pond CapRegrade Area -(6,700 sy)Low Permeability Fill & Placement (3,400 cy)Vegetative Cover Soil & Placement (1 ,100 cy)Hydroseeding (6,700 sy)

Subtotal ___ ....................... ......._..:]!3.T.^^

Stormwater SwaleLow Permeability Fill & Placement (610 cy)Vegetative Cover Soil & Placement (205 cy)Hydroseeding (1,220sy)Energy Dissipation Concrete Bags (50 bags - 50 cy)

Subtotal _ '. "' ZZ.trrr--v':----'V ^ iii ^ EChristina River Edge Sideslope

Excavation (6 cy - 1 day)Transport to "Concrete Jungle" via Dump Truck (1 day)Vegetative Cover Soil & Placement (6 cy)Geogrid & Installation (35 sy - 1 roll)Sod & Installation (310 sf)

Subtotal . . . .• .. ,,.,..,;M':::ri-., ..t

Wetlands AreaRegrade Existing Wetlands (3,900 sy)Excavation (3,100 cy)Vegetate Tidal Wetlands (2,900 sy)Plant Trees & Shrubs on Sideslope (360 sy)

Subtotal " . • ,:!.;!:.'CnFZ:"

$2,650/acre

$1/sy$23/cy$18/cy$0.27/sy

;£i;iiii.

$23/cy$18/cy$0.27/sy$150/cy

&:£i::&

$1000/day$305/day$18/cy$600/roll$0.50/sf

"',';X'!;X;;v'';;;;;;---,;:-,..,y; '.-.-. •:,..- . . . - . - - . .'•-•-' : ••

$Vsy$2/cy

$1.60/sy$8.33/sy

• Y^ i f, : \ ,• •;.. • -,.,'- • .-."'.- _ . . ' - ' r •.-'; ;,-.-; -

$3,710

$3,700

$6,700$78,200$19,800$1,810

ip$10,5||

$14,030$3,690$330

$7,500

m &sm.$1,000$305$108$600$155

$3,900$6,200

$3,ofl

•• ' $1.7,700

TABLE A-2 (Continued)ALTERNATIVE NORTH DISPOSAL SITE - 2REGRADE & COVER CONCRETE JUNGLE

ENHANCE WETLANDS AREA - CONTROL STORMWATERREVEGETATE RIVER'S EDGE SIDESLOPE AREA

PRELIMINARY COST ESTIMATEDUPONT NEWPORT SITE

Item Description Cost Basis

Mobilization & Demobilization lump sum

Grout Existing Outfall 002 (24" dia. 1 50 ft length) $20/cf

•;:.* rT . .T?',1,".' "."* :•:•". S!..T?.K'.VT . 7T/ : : : :>ii™ 1:'HV,>-:V:!>:45S':™y«;SSSft.i -:<f. •• • :• ...... >.-.<-Xf;ir:fi&S:!i---.-- x.i.vri'SKiv:.;;; •:•:••'••:>;;•>,•»?. 'iK*;*'™ *:-¥.W: •;•„•;; W: V* : ......... .'.•.*:••••!: V.1 - •.

Health & Safety (5% of DC)



: Subtotal '•'•:£Wi??:ii?i

Contingency (15%)

__

Operations and Maintenance (30 year period)Groundwater MonitoringMaintenance of "Concrete JungleTSunfish Pond" Cap

;TQTAL*RRESENratf0.l ^

Note: Costs were generated based on 1991 dollars

Cost

$10,000

$9,400

$175,100

$8,800

$17,500

$26,300

ll¥lli:.;;::::SlPO

$34,200

!ii,r$2;6i,£0o

$53,800$12,800

iw::;i-i;;:-;$66,6dO

$329,000

AR3I2J02

TABLE A- 3NORTH DISPOSAL SITE OPERATIONS AND MAINTENANCE COSTS

ALTERNATIVE NDS - 2PRESENT WORTH ANALYSISDUPONT NEWPORT SITE

DISCOUNTED RATE OF RETURN = 5 %

YEAR

123456789101112131415161718192021222324252627282930

GROUNDWATER MONITORING

COST

$3,500$3,500$3,500$3,500$3,500$3,500$3,500$3,500$3 00$3,500$3,500$3,500$3,500$3 00$3,500$3,500$3,500$3,500$3,500$3,500$3,500$3,500••,500

"00;X)

S ;)0$:...;:<)s: X)$ 0$:. .jo

TOTAL O&M PRESENT WOfcTHl

PRESENT WORTH

$3333$3,175$3,023$2,879$2,742$2,612$2,487$2369$2,256$2,149$2,046$1,949$1,856$1,768$1,684$1,603$1,527$1,454$1385$1319$1,256$1,196$1,139$1,085$1,034$984$937$893$850$810

•/.'i; $&*M

CAP/SWALE MAINTENANCE

COST

$830$830S830$830$830$830$830$830$830$830$830$830"5830$830$830$830$830$830$830$830$830$830$830$830$830$830$830$830$830$830

PRESENT WORTH

$790$753$717S683S650$619$590$562$535$510$485$462$440$419$399$380$362$345$328$313$298$284$270$257$245$233$222S212$202$192

;• :': '• -.: i ..:• '••''.' " ''•'.' .'.... : • •• " • • • • , •• • ,.,'•::' :!i;:i,'..:::-.:-'--'--.. i i:!-..,.:*| *> CHA:.:,;: ,-,.:,:: ;,.;.•:,; . '. .-j-.v.-.-.-.-,;.-:- ••.-.• •. & J.4b}OUv

^312/03

TABLE A-4SOUTH DISPOSAL SITE - ALTERNATIVE 2

REGRADE ACCESS ROAD, WETLANDS IMPROVEMENT, & ACCESS RESTRICTIONSPRELIMINARY COST ESTIMATE

DUPONT NEWPORT SITE

Item Description Cost Basis Cost

Access Road ConstructionRegrading (8,000 sy)Gravel Base (2,100 cy)Erosion Control Product (8,000 sy)

•sij6ioi:.:.Institutional ControlsVegetative Barrier (1,060 LF. - 430 plants)Fencing - 6ft with barbed wire (920 L.F.)Gate Entrance (Old Airport Road) - 6ft

' iftii F?':"OMPlQRil::;-S;C::.:.;::>

Culvert for Discharge from Pond (48" dia. - 80 ft)

Mobilization & Demobilization

.Tioiil;:.!llS'J SIP tes ^ ^ iL; ^ S2Health and Safety (5% of DC)



Contingency (15%)•VYr' ' ' •'•'•' i '.'••y.'-'.'.'.'.1.'.' '•••.•-•.•.•,•.•.•. •-••ji' '.'.'.•,'.',•,•.•.'''.'.'.',•:•:•,•:•,•:•:'.••'•••••'•'.'.'.':•:':•:•:' V ', ', '< '• ', J. ', ',• V, '. \. '. '. ', ','. J. ', J , '_, ', '. [, [. L ' S l[. [.'_.'L S, \ \ V ,'. .'., '.. \.\.\ ,\,',,\ .\, V.V . ,\, •'.;.;.;.;.;•;

Operation and Maintenance CostsAccess Road and Fencing/Vegetative Barrier

$1/sy$8.70/cy$0.5/sy

$11.75/plant$15.50/LF.$785/gate

$93/L.F.

lump sum

^ ^ ^ 1 111111: ^

wt-mmmtmmmmytii-imm::-m:m Mm: mm M:-smm

iS iPiiflllllilllS

$8,000$18,270$4,000

fe:$t3b,30Q

$5,050$14,260$785

fll!$.20,!'bQ

$7,440

$4,000

$3,100

$9,300

$9,300

$12,500

$37,500

K$$?$OG:

sWTAPERt B WO

Note: Costs were generated based on 1991 dollarsflf?

TABLE A- 5SOUTH DISPOSAL SITE OPERATIONS AND MAINTENANCE COSTS

PRESENT WORTH ANALYSISDUPONT NEWPORT SITE

DISCOUNTED RATE OF RETURN = 5 %

YEAR

123456789101112131415161718192021222324252627282930

ACCESS ROAD & FENCING MAINTENANCE

COST

$2,020$2,020$2,020$2,020$4340$2,020$2,020$2,020$2,020$4340$2,020$2,020$2,020$2,020$4340$2,020$2,020$2,020$2,020$4340$2,020$2,020$2,020$2,020$4340$2,020$2,020$2,020$2,020$4340

TOTAL O&M PRESENT WORTH i? |l:

PRESENT WORTH

$1,924$1 32$1,745$1,662$3,401$1,507$1,436$1367$1302$2,664$1,181$1,125$1,071$1,020$2,088$925$881$839$799

$1,636$725$691$658$626

$1,282$568$541$515$491

$1,004

'.-.••. V. : v: i "''Efil::l&y. :$3766

A R 3 I 2 I 0 5

Date post:	12-Oct-2020
Category:	Documents
Upload:	others
View:	0 times
Download:	0 times

Woodward-Clyde Consultants · E.I. du Pont de Nemours and Company, Inc. (Du Pont) and...

Documents