Environment!) Protection DopinmtnlCIBA.GEIGV CorpontionArdilty.N.w York 10802-2699T.l.phon«914 4783131

CIBA-GEIGY

RECEIVED

AUG 311990O.J.M.

August 21, 1990

Mr. Eugene Dennis3HW 23Environmental Protection Agency841 Chestnut streetPhiladelphia, PA 19107

Re: Coiieati on BPA Preferred Buudial ActionPlan (or the Deep Aquifer -Tyson auperfund Bite

Dear Mr. Dennis:This letter.and the attached report of ERH are provided

as comments to EPA'o recent selection of a proposed RemedialAction Plan for the deep aquifer at the Tyion Site. I regret tosay that the responsible parties believe that EPA has selectedthe wrong remedy at this time and that the agency should take aphased approach of requiring the conpletion of the recovery welland treatment system on the South side of the river and directingfurther studies of the effect of that action before deciding whatfurther remedy should be taken.

We think that EPA's selection of the preferredalternative for the present operable unit at the Tyson site forgroundwater recovery on Barbadoes Island is contrary to theNational Contingency Plan ("HOP"). A decision now with respectto Barbadow Island does not reflect how this action relates tothe long-ten, comprehensive response at the site. The selectionof recovery wells on Barbadoes Island is only an additionalexpensive remedy which may be totally unnecessary after theexisting groundwater recovery system is expanded from seven tothirteen water recovery wells and the depth of walls increased.It accordingly fails to consider the general principle thatdecisions as to operable units should not be inconsistent with orpreclude implementation of the expected final remedy.

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Mr. Eugene DennisAugust 21, 19902

The Agency's selection of a preferred remedy also doesnot deal with the ordinary expectation that where restoration ofgroundwater to beneficial uses is not practicable, EPA willordinarily only prevent further migration of the plume, preventexposure to the contaminated groundwater and evaluate furtherrisk reduction. Complementary to this is the expectation setforth in the NCP that EPA expects to use engineering controls,such as containment, for waste that poses a relatively low longterm threat or where treatment is impracticable.

Section 300.430(f) of the NCP dealing with selection ofremedies provides in relevant part as follows:

"Remedies selected shall reflect the scopeand purpose of the actions being undertakenand how the action relates to long-term,comprehensive response at the site."

The same concept is expressed in Section 300.40(a) (ii>of the NCP under the title of "Program Management Principles."Subpart (B) provides:

"Operable units, including interim actionoperable units, should not be inconsistentwith or preclude implementation of theexpected final remedy."As pointed in the attached comments of ERM, the

installation of a groundwater recovery system now on BarbadoesIsland would not meet these criteria. As ERM points out,disturbing the bedrock aquifer system by pumping on BarbadoesIsland could prevent us from ever understanding the mechanismsresponsible for the presence of site-related compounds north ofthe river. This in turn could lead to a poorly conceived designof the ultimate remedy for the Tyson site. The ERM comments setforth in detail all of the matters as to which we haveinsufficient knowledge. This lack of knowledge should barprecipitous action in adopting the recovery well system forBarbadoes Island. Precipitous action is unnecessary because therecovery well system which has been installed on the south sideof the river has blocked the flow of contaminated water to theriver and there are no present uses of the groundwater, onBarbadoes Island or on the north side of the river.

The adoption of the recovery well system for BarbadoesIsland also flies in the face of the ordinary expectations setforth in the NCP. Section 430.430(a)(iii)(F) indicates that

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Mr. Eugene DennisAugust 21, 19903

under the circumstances presented by this case, in which remedialaction design to restore the aquifer to beneficial use is notpracticable, EPA should expect only to prevent further migrationof the plume, prevent exposure to contaminated groundwater, andevaluate further risk reduction. As pointed out by ERM, thecompletion of the treatment system in the south side of the rivermay achieve these goals because the tripling of the groundwaterrecovery rate (from 120gpm for the initial system to 350gpm forthe full system) may well influence groundwater flow beneath theisland and north of the river. That remedial action may alsosatisfy the expectations set forth in Section 300.430(a) (iii) (B)as follows:

"EPA expects to use engineering controls,such as containment, for waste that poses arelatively low long-term threat or wheretreatment is impracticable."Finally, cost-effectiveness considerations should also

be weighed. A decision now to place recovery wells on BarbadoesIsland may well commit the Agency to recovery wells there and onthe north side, whereas the phased approach suggested by ERM islikely to result in a better remedy decision which will be morecost effective.

We suggest that the Agency adopt the following decisionin order to provide at this time for a final remedial action:

(1) The participating PRPs will promptlyexpand the recovery well and treatmentsystem as proposed in the Final Draft of theFocused Feasibility study for the River so thatthis phase will be completed by April 30, 1991;

(2) The participating PRPs will submit a work plan byOctober 30, 1990 for completion of the studies onthe north side as proposed in the Final Draft ofthe Focused Feasibility Study of the River andperform the work required by the plan as approvedby EPA; and

(3) The participating PRPs will execute whateverremedy these studies dictate are necessary toprotect users of the water, if any, in or north ofthe River. At a minimum, the PRP Group willprevent further migration of the groundwater plumeby pumping and treating groundwater. The number

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Mr. Eugene DennisAugust 21, 19904

prevent further migration of the groundwater plumeby pumping and treating groundwater. The numberand position of any additional required wells willbe determined during the design phase byevaluating the effect of the full extractionsyntem on the groundwater conditions beneath andnorth of the river.

I urge you to give heavy weight to these comments bythe parties who have given unusual cooperation to EPA in theexecution of remedial action. Undoubtedly, you recognize thatthe PRP group has moved quickly, with minimal need for EPAsupervision, to remediate what must be one of the most complexsites in the Super fund Program. This Group has not onlyimplemented innovative technology to clean up the lagoons, buthas established an effective groundwater recovery and treatmentsystem to prevent further flow of contaminated groundwater beyondthe south side of the river. This has had the salutary effect ofpreventing contaminants from flowing to water intakes on theSchuylkill River of private and public water treatment systems.The Group's commitment to a remedy at this site can be measuredin part by the financial commitment of the responsible partieswhich to date is in excess of $45,000,000.

Our comments flow not from an unwillingness to performremedial action but from a strongly held conviction that EPA'sselection of its preferred remedy is premature. Instead, theAgency should adopt the suggested staged approach which is mostlikely to result in more effective remedial action.

Sincerely

Karline K. Tierney, ManagerEnvironmental Protection

kt/A:dennisEnclosurescc: Consent Decree List

Mr. W. Dunn, UMT

HR3007I9

Vlrglnli Glbion-Hason, Eiq.Chief, Civil Dlvlilon, USEPA Chief, Supetfund EnforctatntUnited States Attorney'^ Office U. S, Envlronnencil Prot. Agency3310 U. S. Courthouse 841 Chestnut Building601 Market Street Philadelphia, FA 19107Philadelphia, PA 19106

Anthony J. Crlao, Eiq. Mr, Tlnothy HcGulnneeiGeneral Counsel Antrlean Hone Product)ESSEX Group, Inc. 685 Third Avenue1601 Wall Street New York, NY 10017Ft. Uayne, Indiana 46804

George Miller, Esq. Ha, Bonnle ScullyDechert, Price & Rhoads PA Dapartnant of Envlronnental3400 Centre Square West Protection1500 Market Street 1875 New Hope StreetPhiladelphia, PA 19102 Norrlitoun, PA 19401

Douglai F. Brennan, Eiq.Bureau of Hazardous Sltee

Donald K. Joseph, Eiq. & Superfund1 EnforceoentUolf, Block, Schorr & Soild-Cohen Office of Chief Counael12th Floor, Packard Building PA Departnenc of Envlronnental Resources15th and Chestnut Street 301 Cheitnut Street • Third FloorPhiladelphia, PA 19102 Harrlsburg, PA 17101-2702

Chief, Dlv. of Emergency &Remedial Response Alan M. Rublnion, Esq.

Attn: Tyson's Lagoon Project Asilstant General CounselOfficer, Bureau of Waste SnlthKllne Beckaan Corp.7th Floor, Fulton Building One Franklin Plaza3rd and Locust Streets Philadelphia, PA 19101Harrlsburg, PA 17120

Mr, David Heal Tluothy A. Vanderver, Jr., Esq.PA Dept, of Envlro Resourcei Patton, Boggs & BlowState Superfund Progra* 2550 M Street, N.U.V. 0, Box 2063 Washington, DC 20037Harrlsburg, PA 17120

Mr, Thomas Beggs Hershel Rlchaan, Esq.SnlthKllne Becknan Corp. Cohen, Shaplro, Polisher,709 Suedeland Road Shlaknan & CohenKing of Pruisla, PA 19406-2799 PSFS Building, 22nd Floor

Philadelphia, PA 19107

HR300720

8. S, PAPADOPULOS A ASSOCIATES. INC.;.-X. GONIULTINO OROUNO-WATIH HVOHOLOOIiTi

t.l, M'AOOPUtOII, P. LAMONC. I, ANDNIWI

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August 28,1990

Mrs, Karline TiemeyCBA-GEIGY Corporation444 Saw Mill River RoadArdsley, New York 10502-2699

Subject: Tyson's Site • EPA's Proposed Remedial Action Plan

Dear Mrs. Tiemey:

As you requested, I reviewed die final draft of the Focused Feasibility Study (FPS) for the Tyson'iSite Issued by ERM on July 19, 1990 and the Proposed Remedial Action Plan (PRAP) for theTyson's Site issued by EPA Region m on July 23,1990. ERM recommends the expansion of theinitial seven-well ground-water recovery system to the full thirteen-well recovery system (Alternative2 of the FFS) and the deferment of any further action until hydrogeologk conditions at the north sideof the river an better understood. EPA's preferred remedy (Alternative 3a of the FFS) also proposesthe expansion of the initial recovery system but it also includes the installation of an additionalrecovery system at Barbadoes Island, The water recovered by this additional system is to be pipedunder the river into the treatment plant on the south bank of the river which will be expanded toaccommodate the additional water,

I agree with bom ERM and EPA that the initial ground-water recovery system at the south side ofthe river should be expanded to in mil thineen-well configuration. However, in my opinion, theinstallation of an additional recovery system at Barbadoes Island, at proposed by EPA, is notwarranted at this time because a) it may not completely prevent the northward migration ofrnmmiinntti ground water (one of the principles that forms the basis for EPA's selection of thisalternative), b) k may not be necessary, or c) it may be redundant with remedial measures that mayhave to to taken at a later date. The basis of my opinions is discussed in the paragraphs that follow,

The primary environmental concerns associated with ground-water contamination within the bedrockaquifer under the Tyson's Site are:

1) The impacts of me discharge of contaminated ground water into the SchuyUdll Riverwhich U a source of public water supplies; and

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9, S, PAMDOPUIOS * AS90CIATM, INC.

Mrs. Karline TierneyAugust 28,1990Page 2

2) The continued migration of contaminated ground water beyond the north bank of the riverwhere it might impact present or potential future users of ground water,

The initial recovery system was designed to capture ground water with (he highest concentrations ofsite-related compounds between the site and the river and thus reduce the impacts of ground-waterdischarge into the river, Since the system began operating, site-related compounds have not beendetected in the south channel of the river, except for a few rare occasions. This indicates that thesystem has been effective in reducing the rate of contaminant mass discharge into the south channelof the river. Site-related compounds have not been detected in the norm channel of the river, Thisindicates that contaminated ground water detected below Barbadoes Island and the north side of theriver either is not discharging into the river or is discharging at such low mass rates that it has noimpact on the river.

Given these present conditions, mere is no environmental reason for taking any further action toaddress the impacts of ground-water discharge into die river. In discussing me risks associated withthe discharge of ground water into the river, EPA concludes "The current carcinogenic risk at theRiver intake is of die EPA acceptable level of 10*." However, the area of contaminated ground watersouth of die river extends beyond the capture zone of the initial system. Part of this ground wateris discharging into die river, with no apparent impact, out part of it, especially that in the deeperhorizons of die bedrock aquifer, continues to migrate northward under the river. Expansion of therecovery system to die full width of the plume south of the river is, dierefon, a remedial action matneeds to be taken to prevent the northward migration of this contaminated ground water. Althouchit is not necessary, the expansion of the recovery system will also provide further protection for theriver.

When implemented, the full recovery system will have a capture zone which will encompass theentire width of the plume south of the river and which, in die deeper horizons of the aquifer, willextend to the north, below and beyond the south bank of die river. Depending on conditions northof me river, contaminated ground water between die northern limit of mil <!apture zone and die northside of the river will either discharge into the river or continue to migrate northward beyond the northbank of the river. The rationale used by EPA in proposing a recovery system at Barbadoes Islandis that this system will capture this ground water and will accelerate die restoration of the aquifer.The presence of DNAPL in the bedrock aquifer as far north as Barbadoes Island indicates thatrestoration of the aquifer is not a goal that could be accomplished in die foreseeable future.Therefore, the primary objective of a recovery system installed at Barbadoes Island would be tocontain hydnuHcally the contaminant plume by capturing northward migrating ground water.However, as discussed below, capture of this ground water may not be necessary and, if necessary,may not be possible by a recovery system at Barbadoes Island.

If the hydraulic gradients within the affected bedrock zones north of the river are toward the river,then ground water beyond the capture zone of the expanded recovery system will be discharging intothe river. However, die amount of discharge into the river would be less than that which may to

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•J|laf *. •• PAPADOPULOS ft AiSOCIATM, INC,

Mrs. Karline TiemeyAugust 28,1990Page 3

occurring at present. Since the risks associated with the present discharge of ground water into theriver are acceptable, no further remedial action would to necessary under these future reduceddischarge conditions. It should to noted mat if die hydraulic gradients north of the river are towardthe river, then the contaminated ground water found norm of the river is also discharging into dieriver, Although EPA estimates the cancer risk associated with the presence of contaminants northof the river to to 2 x 10*, in absence of DNAPL north of the river, continued discharge into the riverunder natural gradients will eventually restore the aquifer north of me river and eliminate this risk,Until the aquifer is restored, temporary measures may to required to prevent the installation of water-supply wells in this area.

On the other hand, if gradients north of die river are toward die north, away from the river, thenground water which is beyond the capture zone of the expanded recovery system will continue tomigrate northward and may potentially impact present or future users of ground water north of theriver. As stated above, the risks associated with the presence of contaminants north of die river havebeen estimated by EPA to to 2 x 10J. Therefore, under these conditions of continued migration tothe north, additional remedial action will to necessary. If the appropriate remedial action li theinstallation of an additional recovery system, the location which will provide for the most effectivecapture would to near the leading edge of the contaminant plume north of the river. A recoverysystem at Barbadoes Island, at least 1,000 feet or more south of the leading edge of the plume, wouldnot provide for complete capture. Furthermore, if a recovery system north of the river is installed inthe future, then a recovery system presently installed at Barbadoes Island would become redundant

Based on die above, I conclude that the remedial action to to taken at present should to dieexpansion of the initial recovery system and that parallel with die implementation of the systemexpansion, investigations should to undertaken to determine the direction and rate of ground-waterflow and the extent of contamination norm of the river. The result! of dwse investigations wouldprovide the basis for determining whether additional remedial actions are necessary and, if necessary,for designing remedial actions that would fully address any remaining environmental concernsassociated with the site.

Sincerely,

S, S. PAPADOPULOS& ASSOCIATES, INC.

Stavros S. PapadopulosPresident

AR300723

Envlronmqntol RMOUKCS MonogqmQnt, Inc.• Suite 208 • 20120 Route 19 North > Mars, Pennsylvania 16046 > (4121 772-1022

16 August 1990

Mrs. Karline TlerneyCIBA-GEIGY Corporation444 Saw Mill River RoadArdsley, New York FILE: 272-23-01-01

RE: Response to EPA's ProposedRemedial Action Plan for theTyson's Site

Dear Mrs. Tierney:On 19 July 1990, CIBA-GEIGY Corporation submitted to EPA RegionIII the final draft of 'The Focused Feasibility Study for the Tyson's Site(FFS) prepared by Environmental Resources Management. Inc. (ERM).In the FFS, ERM recommended an alternative to address the site-related compounds In the deep aquifer ground water from the southbank to the north bank of the Schuylkill River. This alternativeincluded the extension of the existing Interim Ground Water RecoverySystem to the Full Ground Water Recovery System. U.S. EPA RegionIII, upon review of thi FFS, in Its proposed Remedial Action Plandated 23 July 1990, selected Alternative 3a which Included theextension of the Interim Ground Water Recovery System to the FullGround Water Recovery System and the Installation of recovery wellson Barbadoes Island. EPA stated "The preferred alternative (3a)addresses contaminated ground water In the bedrock aquifer that hasmigrated from the site." EPA further states that "The remediationgoals will be to confine the contaminated ground water to BarbadoesIsland through pumping and treating the recovered ground water toacceptable levels," and that "Actual or threatened releases of hazardoussubstances from this site, if not addressed by the preferred alternativeor one of the other active measures considered, may present a currentor potential threat to public health, welfare, or the environment."EPA provided, In Its proposed Remedial Action Plan, the followingthree principles for its selection of Alternative 3a:• The extension of the Interim Ground Water Recovery System to

13 wells on the south side of the river will further prevent thedischarge of contaminated ground water to the Schuylkill River,

AR300721*An affiliate of Th» Environmsnlal Rsiourcii Manugnminl Group wilh otflc«i worldwide

Mrs, Karllne TlerneyCIBA-GEIGY Corporation16 August 1990Page 2

• The Installation of ground water recovery wells on BarbadoesIsland will prevent the northward migration of contaminatedground water.

« The treating of the recovered ground water beneath BarbadoesIsland and on the south side of the river will help In restoring thebedrock aquifer,

ERM strongly believes that the Installation of ground water recoverywells on Barbadoes Island prior to obtaining a more complete under-standing of the dynamics of ground water flow and its Impact on thepresence of site-related compounds beneath the Island and on thenorth side of the river would be premature and may Impact the overalleffectiveness of an ultimate ground water remedy, Disturbing thebedrock aquifer system by pumping on Barbadoes Island could preventus from ever understanding the mechanisms responsible for the pres-ence of site-related compounds north of the river, This In turn couldlead to a poorly conceived and designed ultimate remedy for theTyson's site.ERM believes it is premature to commence with EPA's preferredAlternative 3a because we do not have sufficient Information on triefollowing which could Impact the effectiveness of any ground waterrecovery program for the Tyson's site:• The mechanism by which site-related compounds reached the

north side of the river Is not fully understood. Although It Is prob-able that ground water has migrated towards the north side of theriver from the site, there Is no evidence that site-related com-pounds from the south side of the river are migrating to the northside of the river today. The Inability to monitor ground water flowbeneath each channel of the river and the presence of bothupward and downward ground water flow components at wellsinstalled on the north bank of the river make it Impossible to reli-ably state what the present ground water flow patterns are andwhat will be the effects of ground water pumping on BarbadoesIsland In respect to ground water beneath the Island, the river,and the north bank of the river.

• Whether the mechanism responsible for the presence of site-related compounds on the north side of the river Is still Influenc-ing the site-related compound migration. The presence of site-related compounds on the north bank of the river is not easily

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Mrs, Karllne TlerneyCIBA-GEIGY Corporation16 August 1990'

explained; the dissolved phase concentration? In CW-1 do notindicate that there is a DNAPL on the north side of the river;therefore, the site-related compounds found at this location musthave migrated In the dissolved phase, Ground water levels havenot been measurable at this location, and monitoring wellsInstalled on either side of this well indicate that an upward com-ponent of ground water flow is present, particularly from thedeepest open Intervals to those Immediately above, This compo-nent of flow would be expected if the Schuylkill River was a dis-charge zone, as classical ground water theory would hold. Unfor-tunately, If this were the case at CW-1, ground water flow wouldbe generally Into the river, and thus In the opposite ground waterflow direction required to transport site-related compounds tothis location. A possible explanation for the occurrence of site-related compounds in the dissolved phase Is that historically theground water flow paths were reversed, allowing site-relatedcompounds to migrate to this location and that all that is cur-rently present at CW-1 is the residual dissolved phase contamina-tion from this former flow component. It is known that In thepast, the Norristown State Hospital pumped far greater quantitiesof ground water; In addition, a number of since closed factories inNorristown may have also historically altered ground water flowpaths along the north bank of the Schuylkill River.In addition to this explanation, there Is also the possible existenceof a geologic structure which may play a role In the migration ofsite-related compounds to the north bank of the Schuylkill River.

• Whether the site-related compounds on the north side of theriver are continuing to migrate further north, or are dischargingback to the river. As stated in the previous paragraph, a completepicture of the extent of site-related compounds north of the riverand the direction and rate of ground water flow are unknown.Current water elevation data obtained from wells on the northbank of the river Indicate that both upward and downward flowcomponents exist. Depending on the flow directions at CW-1,DNAPL sources beneath Barbadoes Island may or may not be con-tributing to site-related compounds at CW-1. Without this Infor-mation, designing a ground water recovery program on the IslandIs premature and may result in an inappropriate ground waterrecovery remedy being selected.

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Mrs. Karline TterneyCIBA-GEIGY Corporation16 August 1990Page 4

• Whether pumping ground water from the full recovery system onthe south side of the river and/or whether pumping ground waterfrom wells on Barbadoes Island will have an Impact on the pres-ence of site-related compounds on the Island and north of theriver. Alternative 2 already Includes tripling the ground waterrecovery rate on the south side of the river. The nature of a frac-tured bedrock aquifer makes It impossible to accurately predictthe effect that nearly tripling the ground water recovery rate(from 120 gpm for the initial system to 350 gpm for the full sys-tem) on the south bank of the river will have on the radius ofInfluence for this system. The possibility exists that the systemwould Influence ground water flow beneath the island and north ofthe river. If so, any ground water recovery system on the Island oron the north bank, If necessary, could be designed to Influenceground water flow to maximize the efficiency of these systems.For example, If the full system on the south bank was determinedto be Influencing ground water movement beneath the Island, Itmay be possible, given the knowledge of the effectiveness of thissystem, to design a second system on the Island or on the northbank of the river that addresses the remaining ground wateraffected by site-related compounds, In lieu of installing additionalground water recovery facilities at each location. Also, the Instal-lation of ground water recovery wells and associated pipelines onBarbadoes Island will be destructive of wetlands on the Island.These areas should be avoided If possible, unless absolutelynecessary.

« Whether pumping from wells on Barbadoes Island will provide anyfurther protection of river water quality. Since start-up of theInitial ground water recovery program, the presence of site-related compounds In the south channel of the river has beennearly eliminated, Indicating that this system has been responsi-ble for preventing most, if not all, of the ground water with site-related compounds from discharging Into the south channel of theriver. Both ERM's (#2) and EPA's (#3a) selected alternativesrequire expansion of the recovery system on the south bank of theSchuylkill River; we feel this expansion will provide an extra mea-sure of protection for the river, as well as total hydraulic contain-ment of existing on-slte concentrations. Previously, as part of theOff-Site RI, a number of surface water samples were collectedfrom the north channel of the river; site-related compounds were

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Mrs Karllne TiemeyCIBA-GEIGY Corporation16 August 1990PageS

not detected in this channel, During this monitoring period, site-related compounds were frequently detected In the south channelof the river, The lack of site-related compounds In the northchannel of the river has been Interpreted to indicate that groundwater with site-related compounds Is not discharging In greatenough quantities Into the river to be detected, either fromground water beneath the Island or the north bank of the river.Therefore, the pumping of ground water from beneath the Islandwill not have any measurable effect on the discharge of site-related compounds to the river in this north channel and, appar-ently, ground water discharging into the south channel Is beingaddressed by the Initial ground water recovery system.

ERM believes that EPA's preferred alternative will have little Impacton aquifer restoration due to the presence of a DNAPL and the scien-tific community's inability to recover effectively this material. There-fore, we believe that ground water pumping remedies should be cur-rently focused on reducing the potential effects on existing Identifiedreceptors and then on protection of future possible receptors becausewe have been unable to identify any ground water users north of the g|tSchuylkill River (with the exception of the Norristown Hospital wells MBwhich have been sampled and found not to contain any site-relatedcompounds). It follows that the only current receptor of site-relatedcompounds at the Tyson's site is the Schuylkill River.Considering that it has been about 30 years since the materials wereoriginally deposited In the former lagoons, the theory that DNAPLstend to migrate very quickly to their ultimate extent and that theInterim Ground Water Recovery System has effectively eliminated anyrisk posed to users of the river, ERM feels that to ensure protection ofthis water supply, construction of the Full Ground Water Recovery Sys-tem should begin Immediately.To protect any future users of the aquifer, a phased approach shouldbe taken as follows:• Evaluate the effectiveness of the Full Ground Water Recovery

System;• Obtain needed Information on the north side of the river;• Review the data obtained from both of the above efforts; and

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Mrs, Karllne TiemeyCIBA-GEIGY Corporation16 August 1990Page 6

• Make a decision regarding the value, need, and design of anyadditional pumping wells, if needed,

ERM proposes to accomplish this through the following:

Phase I (each task to be completed concurrently)• Install the Full Ground Water Recovery System on the south side

of the Schuylkill River and expand its associated monitoring wellnetwork:• Install and test new recovery wells (EW-7, EW-8, and EW-9)

and deepen recovery wells EW-10, EW-11, EW-12, and EW-13 (estimated to require at least 10 to 15 weeks).

- During this well drilling activity, two additional multilevelpiezometers will be Installed on Barbadoes Island; these wellswill, with the existing multilevel piezometer (or nested wellcompletion), allow the Full Ground Water Recovery Systemperformance to be more effectively monitored (estimated torequire 8 to 12 weeks),Select well pumps and add all new wells to the recovery wellnetwork (design and construction expected to require 2 to 4weeks).Start up Full Ground Water Recovery System.

• Collect sediment, biota, and surface water samples to allow theeffectiveness of the Full Ground Water Recovery System to bemore completely determined. This will Include collection ofSchuylkill River sediment and biota samples from previouslysampled locations and continued monthly collection of surfacewater samples from the south channel of the river (river cribintake and other down river locations). Samples will also be col-lected from the north channel to provide additional evidence ofthe lack of site-related compound migration Into this portion ofthe river.

• Submit a work plan for actions to define the northern extent ofsite-related compound migration. The work plan will Include theinstallation of additional wells north of cored well CW- 1. Theseactions would start after EPA approval of the work plan. '

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Mrs, Karline TlerneyCIBA-GEIGY Corporation16 August 1990Page 7

Phase IIEvaluate the performance of the Full Ground Water Recovery Systemby operating the system until ground water levels In site monitoringwells are stabilized, then conducting a recovery test to allow therecovery well system's performance to be evaluated both in respect toground water beneath Barbadoes Island and on the north side of theriver.

Phase IIIThe results of Phases I and II will be used to evaluate the effectivenessof the full recovery system and will provide a basis for recommendingthe best overall ground water remedy. Phase III will require that thefollowing determinations be made:• Whether the full recovery well system does or does not reverse

ground water gradients beneath Barbadoes Island and beneath thenorth bank of the river.

• Whether the direction of the ground water flow gradients alongthe north bank of the river are toward or away from the river.

• Whether site-related compounds are or are not discharging intothe north channel of the river.

Although this approach could be more costly in the long run, ERMbelieves that it is more scientifically sound and will ultimately lead tothe most appropriate ground water remedy for the Tyson's site.

Sincerely,

Rudolph M. Schuller, P.O.Principal

RMS:cp

UR300730

^Applied Groundwater Research Ltd.~ StuF*nitrtU,Sc,,CQWP

/~s OHlct: 4ie-SIO-t1SO1 } n» tlMOBl Building, 220 Brittnnli Rd E, Ftx: 416-S68-4SSB

Ontario, Cmnit L4Z1S6 torn* 416-824-1304

Tuesday August 21,1990

US Environmental Protection AgencyRegion HI841 Chestnut StreetPhiladelphia, PA19107

ATTENTION: Mr, Eugene Dennis

RE: COMMENTSOFEPAPHOPOSEDREMEDIALACnONPLAN-JULY23,19eOTYSON'S DUMPS1TE, MONTGOMERY COUNTY, PA

Dear Mr, Dennis,

We have been asked by Ms, Karllne Tiemey of CIBA-GEIGY Corporation to provide, to you,our comments regarding the Remedial Action Plan for the Tyson's Dumpsita proposed by EPAon July 23,1990. As you know, we have been involved, on behalf of CIBA-GEIGY, in theevaluation of groundwater contamination and remedial alternatives for the Tyson's sitesince 1986. We make our comments based on our specific understanding of this site, and alsoon our eiperience at other sites and the results of current research on the behaviour of DNAPL(dense non-aqueous phase liquid) in the subsurface.

It is our understanding that the Remedial Action Plan proposed by EPA, referred to asAlternative 3a, includes the following:

• ExpsVsflJMJnit'biiMTiin Groundwater Recovery System on the south side of the SchuylkillRivtrj Bptitting 7 wells to the Full Ground Water Recovery System consisting of 13

• Installation and operation of a groundwater recovery system on Barbadoes Island.

AR30073I

Full Groundwittr fUcovory System on South Side ol Rlvtr

The purpose of the Interim Groundwater Recovery System is to reduce the discharge of site-related groundwater contaminants from the site into the Schuylkill River, The InterimGroundwator Recovery System has reduced significantly the concentrations of site-relatedcompounds (specifically 1,2,3-trichloropropane) found in the south channel of the SchuylkillRiver, Trichloropropane exceeded the « porting limit of 0,5 ug/L in only two of 40 river watersamples collected since the Interim Groundwater Recovery System began operation, In the 15months prior to startup of the system, trichloropropane exceeded 0,5 Mg/L in 12 of 37 river watersamples collected (ERM Focused Feasibility Study, July 19,1990, p, 1-5), The occasionalfinding of trichloropropane in the south channel of the riVer suggests that InterimGroundwater Recovery System does not prevent completely the discharge of contaminatedgroundwater into the river, The purpose of the expansion to the Full Groundwater RecoverySystem is considered by EPA to be more complete capture contaminated groundwaterdischarge from the Bite into the river. We concur with the purpose of this action and believe itwill be effective in reducing the concentrations of site-related compounds in the river to belowthe reporting limits,

It is also considered by EPA that recovery of groundwater from along the south side of the riverwill help in restoring the bedrock aquifer and this was one principle considered by EPA inselection of the preferred alternative, It is clear that recovery and treatment of contaminatedgroundwater will remove some mass of chemical from the subsurface, However, the rate ofmass removal via groundwater recovery will be insignificant compared to the chemical masslikely to be present in the subsurface as DNAPL at this site. In theoretical term;, the removalof any amount of mass may be viewed as help in restoring the bedrock aquifer, however, inpractical terns, over the time scale (possibly hundreds of years or more) likely to be requiredfor aquifer, rtstorttion it should not be construed that groundwater recovery will help

Syittm on Barbados! Island

The purpose of the installation and operation of a groundwater recovery system on BarbadoesIsland is considered by EPA to be help in restoring the bedrock aquifer, and reduction in thepotential for migration of contaminated groundwater to the north side of the river. For thereasons described above, we believe that a groundwater recovery system on Barbadoes Islandwill not help in restoring the bedrock aquifer. Based on our understanding of the site at the ^^

&R300732

^^ present time, we cannot conclude that a groundwater recovery system on Barbadoes Island} would have any influence on the migration of contaminated groundwater toward or beyond the

north side of the river,

Site-related compounds have been found in groundwater at the north bank of the river, Thesource of these site-related compounds and the pathways for their migration to the north side ofthe river are not yet understood. A variety of factors such an geologic structure, the depth andlocation of DNAPL beneath the river, or the influence of hydraulic sinks such as past pumpingof wells at the Norristown State Hospital may have influenced the occurrence of site-relatedcompounds now found on the north side of the river, The lack of hydraulic response inpiezometers on Barbadoes Island and on the north side of the rivor due to the shutdown of theInterim G •wind Water Recovery System on the south side of the river suggests poor hydraulicconnectior beneath the river, In fractured rock formations it is frequently difficult to predicthydraulic connection due to complex fracture geometry and variable fracture interconnection.It is possible that groundwater recovery on Barbadoes Island may have no effect on reducinggroundwater contamination on the north side of the river,

On the basis of this hydrogeologic uncertainty alone, we would not recommend that"""%, groundwater recovery system on Barbadoos Island be installed until further investigations~..J are conducted, In addition, the disturbance of the hydrogeologic system as a result of operation

of a groundwater recovery system on Barbadoes Island may confound any future attempts tounderstand the conditions which resulted in groundwater contamination on the north side ofthe river, Without a suitable understanding of these conditions, it is unlikely that cost-effective remedial actions can be selected.

Because no site-related compounds are presently detected in the north channel of the river andthere are no present groundwater users close to the north side of the river, the timing forimplementation of any remedial measures on the north side of the river is not critical. We

|;it*ted program of investigation and remedial design be undertaken to deal" r contamination beneath Barbadoes Island and the north side of the river.

Concluih

We concur with proposal of EPA to expand the Interim Groundwater Recovery System to theFull Groundwater Recovery System along the south side of the river. We believe that the FullGroundwater Recovery System should further reduce the discharge of contaminated

RR300733

groundwater to the river and should further reduce the concentration of site-related compoundsin the river.

We consider that the installation and operation of a groundwater recovery system onBarbadoes Island at the present time will not likely achieve the desired purpose of solving theproblem of groundwater contamination on the north side of the river, We recommend a stagedprogram of investigation and remedial design be undertaken to develop the most appropriatemeasures to deal with groundwater contamination beneath Barbadoes Island and the northside of the river,

We hope that you will find these comments useful In your development of remedial plans forthe Tyson's site,

Yours truly,

John A. Cherry, Ph, D,Consulting Hydroffcologlst

Stan Feenstra, M. Sc., CGWPApplied Groundwater Research Ltd.

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August 31, 1990

HAND DELIVER

Mr. Thomas C, VoltaggioChief, Superfund BranchEnvironmental Protection AgencyRegion III841 Chestnut StreetPhiladelphia, PA 19106

Re: Tvson Superfund SiteDear Tom:

I would like you to read the comments of theresponsible parties in this case in response to the Agency'sdesignation as a preferred remedy placing recovery wells onBarbadoes Island and running a pipeline through bedrock under theriver to the treatment plant on the south side of the river. Myclient, CIBA-GEIGY Corporation, and the other responsible partiesfeel strongly that this selection of a preferred remedy for thebedrock aquifer is at least premature until further informationcan be gathered to determine where recovery wells would be mosteffective in protecting users of water in the river and on thenorth side.

This belief does not flow from a reluctance to providea remedy. As you probably know, the remedial measures which theresponsible parties have undertaken have been effective inblocking th« flow of contaminated groundwater to the SchuylkillRiver to tha extent that detectable levels of contaminants are nolonger found there. The cost of this remedy to the responsibleparties to date is in excess of $40,000,000.

As you'll see by the enclosed comments, the responsibleparties think that the agency should take a staged approach byfirst adding to and deepening the recovery wells on the southside of the river to see what effect this has on the deep aquifer

AR300735

Mr. Thomas c. VoltaggioAugust 31, 1990Page Two

and by further studies to determine what the most effectiveplacement of recovery wells elsewhere would be.

Please let me know if you would like to discuss any ofthis with the responsible parties before the agency moves to afinal decision on the remedy for the deep aquifer.

Very truly yours,

George J. Miller

c: Mr. Eugene Dennis (Hand Deliver)Donald Joseph, EsquireHershel J. Richman, EsquireDuane Siler, EsquireKarline TierneyRobert A. Naidus, Esquire

AR300736

t

COMMONWEALTH OF PENNSYLVANIADEPARTMENT OF ENVIRONMENTAL RESOURCES

Bureau of Waste ManagementHazardous Sites Cleanup Program

Norristown Regional Office1875 New Hope StreetNorristown, PA 19401

(215) 270-1948

August 22, 1990

Mr. Eugene DennisRemedial Project ManagerU.S. EPA Region III (3HW23)841 Chestnut BuildingPhiladelphia, PA 19107

RE i Review of the ProposedRemedial Action Plan,Tyson's Dumpsite

Dear Mr, DennistSince EPA's publishing of the ProposedJtemedial Action Plant Tyson'sDumpaite,Upper Morion Township,Montgomery County. Pennsylvania, theDepartment has developed guidance for the review of proposed plans.Therefore, the following comments are offered for consideration forfuture proposed plans as well as for the one at hand.

The proposed plan does not identify the lead and support agencies for theTyson'B Dumpsite. As signatory for the Consent Decree, the Departmentshould be identified as a support agency.

The proposed plan does not address environmental risks, We suggest thatany future proposed plan identify environmental risk issues.

The proposed plan does not identify any major State ARARs, although apreliminary explanation of Pennsylvania ARARs were provided to the EPA ina letter dated July 12, 1990. Specifically, the discussions within the"EPA Preferred Alternative" section and the "Compliance with ARAR's"section should have indicated the followingi

RtcycltdPspir •HR300737

August 27, 1990 Page 2Mr. Dennis

* As the Department stated in our July 12, 1990 letter, the (, 1following language, which is based upon the standardPennsylvania groundwater ARAR and which is reflective of thesite's history, is to be included in the Record of Decisioni"The Pennsylvania ARAR for groundwater for hazardous substancesis that all groundwater must be remediated to "background"quality as specified by 25 PA Code Section 75.264(n). TheCommonwealth of Pennsylvania also maintains that the requirementto remediate to background is also found in other legalauthorities."

* The "EPA Preferred Alternative" section should have included anexplanation of how the chosen alternative would meet groundwatercleanup standards. In particular, the discussion should haveclarified that the effectiveness of the recovery and treatmentsystem would be measured against the groundwater cleanupstandards specified in the Record of Decision. In addition, thediscussion should have specified the groundwater and surfacewater sampling frequency, and that the proposed five-year formalreview of the site is pursuant to Section 121(c) of CERCLA.

* The first sentence within the "Compliance with ARAR's" sectionsuggests that groundwater remediation will continue only untilNPDES limits are met, rather than until groundwater cleanupstandards specified in the Record of Decision are met. Thissection should be modified to indicate that groundwatertreatment will meet the contaminant-specific cleanupspecified in the Record of Decision.

* Although the ARARs provided to EPA in the Department's July 12,1990 letter were referred to as "preliminary", they were onlypreliminary to the extent that numeric cleanup and NPDES valueshad not yet been developed for this particular upcoming Recordof Decision. However, the July 12, 1990 letter did referencenumeric cleanup and NPDES values which had been developed forthe Declaration for Record of Decision dated September 30, 1988.Furthermore, the ARARs provided in the July 12, 1990 letterwithin the "Air" and Wetlands/Floodplain" sections are final andcould have been included within the proposed plan.

The Department requests that EPA include this letter in theAdministrative Record, and that EPA provide a response to these commentspursuant to Section 121(f)(l)(G) of CERCLA.

flR300738

August 27, 1990 page 3;ir. Dennis

It you have any questions or comments, feel free to contact me at (215)270-1923. v '

cci J. Feola, E.P. Manager, Norristown RegionM. Bobek, HSCP Operations Supervisor, Norristown RegionW. Lynn, ARAR Committee Chairman, Norristown RegionD. Brennan, Assistant CounselB. Scully, Project OfficerNorristown HSCP PileRe 30 (BJS) TYSPP

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HR300739