SAVAGE WELL POTENTIALLY RESPONSIBLE PARTY (PRP) … · Comment 5, Page 1-3, first line. See the...

KENNETH F. GRAFJOHN R. MCLANE. JR.ROBERTA. RAULERSONJACK B. MIDDLETONJOHN A. GRAFCHARLES A. DEGRANDPREJAMES R. MUIRHEADPETER B. ROTCHARTHUR G. GREENEROBERT A. WELLSR DAVID DEPUYBRUCE W. FELMLYJAMES C HOODJ. CHRISTOPHER MARSHALLROBERT E. JAURONTHOMAS J. DONOVANLINDA CRANDALL CONNELLWILBUR A. GLAHN, IIICAROL ANN CONBOYWILLIAM V. A. ZORNGREGORY H. SMITHRICHARD A. SAMUELSKEVIN M FITZGERALDBRANCH S. SANDERSDAVID E. BARRADALESTEVEN V. CAMERINOJOSEPH A. FOSTERRUTH ANSELL

OF COUNSEL

NORMAN E. D'AMOURS

McLANE, GRAF, RAULERSON & MIDDLETONPROFESSIONAL ASSOCIATION

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August 9, 1991

JUDITH A. FAIRCLOUGHCONNIE BOYLES LANERALPH F. HOLMESMARIA HOLLAND LAWKATHLEEN M. ROBINSONALICE K. PAGEMICHAEL L. HENRYPETER D. ANDERSONTHOMAS W. HILDRETH*PAMELAJ. NEWKIRKMICHAEL B. TULESTEPHEN C. WILLIAMSKEVIN M. LEACHJOSEPH D. LEVERONEMICHAEL J. OUINNCHRISTINE S. ANDERSONDAWN B. BROWNWILLIAM STUDZINSKI, JRSUZANNE M. GORMANMARK C. ROUVALISANNE M. EDWARDSJEFFREY A. OLSENSTEVEN M. BURKEEILEEN L. KOEHLERCHARLES F. GERNAN, JR.GEMMA M. DREHER

"ADMITTED IN MAINE

Richard Goehlert ..U.S. EPAJFK Federal BuildingHSN CANSBoston, MA 02203-2211

Re: Savage Well PRP Group - Comments on EPA Required Changes toFeasibility Study, Dated February 25, 1991

Dear Mr. Goehlert:

This letter will provide the Savage Well PRP Group's comments onthe revisions to the Feasibility Study draft, dated February 25, 1991,which we incorporate herein by reference. By letters dated April 21,April 22, April 25, April 29, May 15, May 16, May 17, June 13, June18, and June 19, 1991. EPA submitted comments on the draft FS whichwere in its words "non-negotiable." This letter is intended toidentify those areas in which the PRP Group disagrees with the changesEPA required to be made. These comments are to be considered a partof the administrative record in this case. As the Group has stated inearlier correspondence with EPA, none of the changes which the EPA hasrequired to be made in the FS should be construed as admissions offact or liability by any of the PRPs. The numbers and page numberslisted below correspond to the number of the comment and page numberof the February 25, 1991 draft of the FS, respectively, to which thecomment was directed. Our responses are to the final set of EPAcomments on various sections of the FS, and certain responses may nowbe moot due to subsequent changes to which EPA agreed.

J

EPA's April 21. 1991 Comments

Comment 1. The Group has no comment on the changing of the coverfor the FS and RI to read Savage Municipal Water Supply Site. Thecomment further mentions that certain quotations lack appropriatereferences, but does not provide any example where such references are

Richard GoehlertAugust 9, 1991

lacking. Vague, inaccurate criticisms such as this provided the Groupwith no opportunity to respond. Accordingly, the Group has noresponse to EPA's comment.

Comment 1, Page 1-1, second and third lines. See Comment 1above.

Comment 3 Page 1-1, 4th line. EPA has required the deletion oftwo sentences. The text required to be deleted is included here andshould have remained in the FS: "In a time frame that is reasonablegiven: (1) the land-use characteristics of the site? (2) the natureand extent of contamination; (3) the nature of the sources of conta-mination; and (4) the nature of the current impact to human orenvironmental receptors posed by the contamination."

EPA questions in its comments where factors 3 and 4, above, "comefrom." EPA need look no further than its own National ContingencyPlan (NCP) which specifically requires the Feasibility Study to"assess site conditions and evaluate alternatives to the extentnecessary to select a remedy." NCP Section 300.430(a)(2). The wholepurpose of the NCP and of the RI/FS process is to assess site condi-tions as they exist to determine an appropriate remedy. Certainly,the nature of sources of contamination, in this case DNAPL sources, aswell as the lack of current risks to human health and the environmentposed by the contamination at the site, should be driving forces inthe selection of any remedy. Moreover, the comment statement that thesite was once a drinking water source and can "once again be a drink-ing water source" is simply inaccurate. The Town of Milford hasalready gone on record as stating that it would not even consider theSavage Well as a source of water supply for at least thirty years. Inaddition, locating a well downgradient from the known or suspectedfree phase DNAPL sources would be locating a drinking water welldirectly in the path of a contaminant source. As a matter ofpracticality and common sense, such a location would be foolhardy.Thinking of the Savage Well as a future water source is not eventaking into consideration the fact that the well is now owned byHitchiner Manufacturing Company, that it is located in an areadowngradient from and surrounded by industrial and commercial ac-tivities, that it is located near a major roadway making it suscep-tible to impacts from spills and vehicular accidents, and that it isin an area that is targeted and zoned by the Town for industrial orcommercial development. In fact, State law and policy precludes thelocation of a public drinking water well in such an area. See Env-Ws372. For all these reasons, it is highly unlikely that the SavageWell and surrounding aquifer will ever be used as a drinking watersource.

EPA also objects to the Feasibility Study's effective quotationof the NCP in defining the specific objectives of the FS. Contrary toEPA's claim that the specific objectives inappropriately use the NCP,


the introduction to the NCP states: "EPA expects to return usablegroundwater to their beneficial uses wherever practicable, within.atime frame that is reasonable given the particular circumstances ofthe site. When restoration of groundwater to beneficial uses is notpracticable, EPA expects to prevent further migration of the plume,prevent exposure to the contaminated groundwater, and evaluate furtherrisk reduction." NCP Section 300.430(a)(1)(III)(F). The specific ob-jectives mentioned in the Feasibility Study as submitted were an ac-curate reflection of EPA's own regulations. Because of the siteconditions listed in the previous paragraph, restoration is not prac-tical. The PRP Group has always contended that containment of theplume and prevention of exposure were the remedial actions required atthis site.

While EPA's comment claims that the primary objective of the FSis to ensure that appropriate remedial alternatives are developed andevaluated, the NCP states: "The purpose of the remedy selection pro-cess is to implement remedies that eliminate, reduce or control risksto human health and the environment." NCP Section 300.430(a)(1).Contrary to EPA comments that the Group has "contrived" excerpts fromthe NCP, the February 1991 draft FS accurately reflects the site-specific analysis and flexibility that the RI/FS process was designedto embody.

Comment 4, Page 1-1, second paragraph, third paragraph and firstparagraph on Page 1-2. See the Group's response to Comment 3 above.The text EPA has required to be deleted is included here and shouldhave remained in the FS.

"The FS develops remediation goals for the site from the findingsof the remedial investigation and the baseline risk assessment. Basedon those findings, it specifies the contaminants of immediate concern,the potential exposure pathways of concern, and the concentrations ofcontaminants for each exposure pathway that are deemed to be appropri-ately protective of human health and the environment and to complywith applicable or relevant and appropriate requirements (ARARs) forthe site."

"The remediation goals so developed are based on 'reasonablemaximum exposure scenarios,' i.e., on the maximum exposures reasonablylikely to occur, rather than on the worst-case exposure assumptions.It then identifies potentially suitable technologies, evaluates themand assembles them into remedial alternatives designed to meet theremediation goals."

"As provided in the March 1990 NCP, the analysis of technologiesand remedial alternatives for meeting the remedial goal should beappropriate for the complexity of site-specific conditions. As dis-cussed in Section 2.0, the remedial objectives for the Savage WellSite are relatively straightforward, involving only one class of


contaminants of concern (chlorinated hydrocarbons) in one environmen-tal,medium (groundwater). The contaminant sources likely existlocally as dense non-aqueous phase liquid (DNAPL). Accordingly, thereare a limited number of remedial options that could be applied to thesite to deal with the contaminants as they exist. The FS has there-fore focused upon the alternatives most likely to provide solutions toidentified site contamination."

Comment 5, Page 1-3, first line. See the Group's response toComment 1 above.

Comment 6, Page 1-3, figure 1-1. The PRP Group has no comment.

Comment 7, Page 1-3, second paragraph. As noted in the Group'scomments on the RI changes required by EPA, the Group does not objectto having facts about the use of the Savage Well as a water supplyfrom 1960 to 1983, as long as it is recognized that the Town ofMilford no longer owns the well and that it is now a private waterwell for use for industrial purposes. The EPA's required deletion ofa statement of fact as to the current ownership of the Savage Well isarbitrary and fails to provide a complete portrayal of facts at thesite.

Comment 8, Page 1-3, third paragraph. See the Group's responseto Comment 7 above.

Comment 9, Page 1-3, fifth paragraph. EPA has required the in-sertion of a sentence concerning the location of groundwater monitor-ing wells in a paragraph discussing the concentrations of VOCsdetected in the companies' production wells. The required insertionis misplaced and should be deleted.

Comment 10, Page 1-8, second paragraph. For the reasons statedin response to comment 7, the deleted language should have remained inthe FS text. The deleted language is as follows: "The site wasincluded on the NPL primarily because the Savage Well was formerly adrinking water supply. However, the well is no longer a potentialpotable water supply because Hitchiner Manufacturing Company purchasedthe well in 1988 for industrial water supply purposes, and the area issupplied with potable water from an alternate source."

See also the Group's responses to EPA's Comment 1 concerning thepotential future use of the aquifer.

Comment 11, Page 1-8, last paragraph. EPA has required the dele-tion of the phrase: "which are all potential sources of contaminationto the aquifer" in discussing industrial, commercial, residential andagricultural uses of the Savage Well Site. Once again, by deletinglanguage concerning existing site conditions, EPA creates a misleadingimpression that the aquifer may at some point in the future be usable


as a public water supply. The various commercial uses surroundingthat aquifer make such a future use extremely unlikely because of thereal potential for contamination.

Comment 12, Pages 1-16 and 1-17. The Group has no comment on thechanges regarding the gains or losses of water in the Hitchiner-Hendrix discharge stream.

Comment 13, Page 1-19, fourth paragraph. The Group has no com-ment as to whether all residences along North River Road use wells fordrinking water or whether just some of them do. The Group assumes,however, that EPA has a factual basis for requiring this change.

Comment 14, Page 1-19, last paragraph. To the extent that EPA'srequired changes in the discussion of ambient air levels at the sitelead to the conclusion that air is a pathway of concern for purposesof remedial objectives, the Group strongly disagrees with such an im-plication. EPA's required change, however, does not appear to arriveat the conclusion that ambient air poses a risk at the site, andaccordingly, the Group does not object to the conclusion.

Comment 15, Page 1-21, last paragraph. EPA has required thedeletion of the statement that the presence of VOCs in vadose zonesoils is not "at levels high enough to serve as a long term source forgroundwater contamination." EPA states that the facts in this para-graph are presented "in an inappropriate manner" but fails to suggesthow they might be revised to make them more appropriate. The factremains, as stated in the now deleted text, that elevated levels ofPCE in soils were significantly lower than the levels of PCE detectedin groundwater at O.K. Tool and do not serve as sources of groundwatercontamination. Statements of fact, such as the one referenced here,belong in the FS. EPA's requirement to delete them is arbitrary andcapricious.

Comment 16, Page 1-22, first paragraph. The Group has no commenton the required change in the definition of metal debris. The Groupfurther has no comment on the addition of levels of various metalslocated at O.K. Tool, except to incorporate by reference the conclu-sions presented in ESE's June 28, 1991 report (see Exhibit 1 hereto)to EPA that it is unlikely that hexavalent chromium is present at O.K.Tool.

Comment 17, Page 1-22, second paragraph and fifth paragraph. ThePRP Group has no comment on the required additions.

Comment 18, Page 1-23. EPA has required the deletion of thefollowing sentence: "The source of acetone and TCA detected in surfacewater appears to be permitted process water discharges from theHitchiner facility." In the same comment, EPA has required the dele-tion of this language: "It should be noted that the Hitchiner NPDES


permit allows discharge of total VOCs at levels up to 600 ug/1 andthat the historical Hendrix permit allowed total VOC discharges up to600 ug/1." Both of these statements of fact should have remained inthe FS. Discharges pursuant to NPDES permits are specificallyexempted from CERCLA liability and remediation, and therefore arestatutorily relevant to any remedial action selected. The Groupobjected to this deletion from the RI, and it renews that objectionhere. EPA has again acted in an arbitrary and capricious fashion inordering selective factual deletions.

Comment 19, 19-a through 19-d. EPA's required changes have beenmade and the Group has no comments.

Comment 20, Page 1-25 or table 1-2. The change has been made.

Comment 21, Page 1-48, first paragraph. The PRP Group objects tothe addition of the phrase "thus making it impossible for leakage ofwater to result in contamination in the bedrock well." The use of theword "impossible" appears to the Group to be an overstatement with nobasis in fact.

Comment 22, Page 1-48, last paragraph. See the Group's responseto Comment 13 above. In addition, EPA's required statement that moni-toring of bedrock and household bedrock wells should be undertaken ona minimum yearly basis lacks any foundation in fact. As noted in theRI, the residential wells are located topographically upgradient fromMW-30 in terms of both ground surface and bedrock surface and arelikely hydrologically upgradient as well. No VOCs have been detectedin any of the eight residential wells sampled. The topography of thesite, in combination with the groundwater flow, which is away from theresidential wells, make further monitoring of the household wellsarbitrary, capricious, unnecessary and a waste of time and money.

Comment 23, Page 1-49, first paragraph. The Group disagrees withthe statement that PCE "was historically present" at several indus-tries, and the statement that the distribution of PCE in groundwaterindicates there may be additional sources at the site. The RI con-tains no information that PCE "was historically present" at severalindustries. Only one company, O.K. Tool, used PCE in its manufactur-ing processes. In any event, evidence of usage of minimal quantitiesof PCE at a facility, without more, would not lead to the conclusionthat there are additional PCE sources at the site. The only othersuspected DNAPL source of PCE is in the vicinity of MW-20 and that hasyet to be confirmed. The statement as written would lead the reader tobelieve that there are unknown PCE sources throughout the mile-longsite which continue to contaminate the aquifer. Such an implicationis, simply put, wrong.

Comment 24, Page 1-49, second paragraph. The Group objects tothe deletion of the phrase that TCE and DCE are derived from a common


principal source. None of the four PRPs have used these chemicals,according to the chemical usage table in the RI, and the FS correctlynotes that they are all degradation products of PCE. Given thesefacts, it only is common sense that the detection of these chemicalsderives from the biodegradation of PCE.

Comment 25, Page 1-49, fourth paragraph. The Group objects tothe addition of the phrase "in the aquifer below the Hitchiner andHendrix facilities." In a subsequent EPA revision, this phrase wasdropped and the Group has no further comment on the required changehere.

Comment 26, figure 1-26. The PRP Group has no comment.

Comment 27-a and 27-b. EPA once again required a discussion offree phase DNAPL sources at Hitchiner when discussing PCE. As notedin the comments to the required RI changes, there is no evidence tosuggest that there is such a source at Hitchiner. Moreover, EPA hasrequired the deletion of the following sentence: "regardless of theexistence of DNAPLs, the high levels of groundwater contaminantsadjacent to O.K. Tool indicate that this location is a source forcontinued long-term migration of contaminants into downgradientportions of the aquifer."

The EPA required language now encompasses an area much broaderthan the one around the O.K. Tool facility and includes the Hitchinerpremises in connection with free phase DNAPL PCE sources or highlevels of PCE. The paragraph as written is misleading and inaccurate.

Comment 28, Page 1-51, second paragraph. The PRP Group incorpo-rates by reference the comments of Hendrix's April 27, 1991 letter toEPA (see Exhibit 2) and Hitchiner's June 5, 1991 letter to EPA (seeExhibit 3) in response to these required changes.

Comment 29, Page 1-51, second paragraph, last line. The PRPGroup has no comment on this change.

Comments 30 and 31. The changes have been made.

Comment 32. The Group has expressed its comments to EPA aboutrequired changes to the risk assessment in a separate document that ispart of the March 20, 1991 baseline health risk assessment (seeExhibit 1). The Group incorporates by reference those comments to therequired changes in the FS discussion of risks posed by current andpotential future uses of the site. The text required to be deleted isas follows:

"Four exposure scenarios were analyzed that apply to the presentuse of the property (contact with water and sediment in the streamnorth of Elm Street, worker contact with soils or sediment as in the


Hitchiner [and] Hendrix area south of Elm Street, contact with surfacematerials at the O.K. Tool facility, inhalation of volatiles inambient air). Of these potential exposures, exposure to surface waterand sediment appears to pose limited risk (3 x 10-6 risk and hazardindex below 1 for maximum exposure), as it is at the lower end of therisk range specified by EPA in establishing cleanup goals (1 x 10-4 to1 x 10-6 risk, hazard index < 1). A very low-to-moderate risk, andthe widest range in estimated risks is associated with chronic expo-sure to VOC in ambient air (2 x 10-8 to 2 x 10-5, hazard index below1). This exposure is associated with perhaps the greatest uncertain-ty. A moderate risk (2 x 10-5, hazard index slightly above 1, noindividual hazard quotient above 1) is associated with soil contact atthe O.K. Tool facility."

"Four exposure scenarios apply to potential future uses at thesite (ingestion of groundwater, irrigation with groundwater, residen-tial-type use of the Hitchiner, Hendrix and O.K. Tool Properties).High risk is associated with chronic ingestion of water — it is clearthat the groundwater at much of the site is not suitable for continualconsumption in its present condition. A municipal system currentlysupplies drinking water to the area. Low risk was associated with theirrigation exposure scenario (risk of 2 x 10-7, hazard index below1)."

"Moderate-to-high risk relative to target risk levels was esti-mated for potential future use of the Hitchiner, and Hendrix and O.K.Tool facilities for residential-type frequent contact scenarios (risklevels of 7 x 10-5 and 3 x 10-4) for the maximum exposures atHitchiner, and Hendrix and O.K. Tool, respectively, although theprobability for such exposures occurring may be low."

"In summary, the only exposure scenarios at the site which pro-duced risks above the target range (1 x 10-4 and 1 x 10-6) weretheoretical future exposures to groundwater and theoretical futureresidential-type contact scenarios for soils at O.K. Tool, whichappearfs] to be an unlikely scenario. There were no current exposurepathways identified which pose an unacceptable risk to human health."

"The results of the risk assessment and the results of the char-acterization of the nature and extent of contamination, as discussedin the preceding summary, form a basis for the development of remedialresponse objectives in Section 2.0 and for the development andevaluation of remedial alternatives in Section 3.0 and 4.0."

EPA's April 22, 1991 Comment Letter on the Analysis ofAlternatives for the Site

The Group has no comments at this time on the EPA's requiredinsertion of alternatives MM-11A and MM-11B.


EPA's April 25, 1991 Comment Letter on FS Section 2 and PartiallySection 4

Comment 33. EPA has required the deletion of pages 2-1 through2-4 and the first paragraph of page 2-6, requiring those pages to bereplaced with language from another FS at another site. Without reit-erating all of the material in the deleted pages, which the Group in-corporates by reference (see attached as Exhibit 4), it is sufficientto state that EPA has required the deletion of site specific informa-tion relative to an appropriate development and analysis of alterna-tives. Contrary to EPA's accusations, there has been no short cir-cuiting or confusion in the process of developing alternatives nor ofthe document's use of the NCP. In fact, EPA's own "quotations" fromthe NCP do not appear in the NCP at all. If they appear anywhere(since EPA has not cited to the regulation itself), it must be in thecomments to the 1990 promulgated version of the NCP, which are notpart of the NCP.

The information contained in the deleted pages is simply ananalysis of site specific conditions, which the NCP itself requires tobe considered. Thus, such factors as free phase DNAPL sources at thesite, state regulations concerning the siting of drinking water wells,the commercial, industrial and agricultural use of the site, as wellas the lack of its current use as a drinking water source are allrelevant factors that must be considered in selecting an appropriateremedy. It serves no useful purpose to evaluate the site while pre-tending (as EPA expressed its intention to do) that none of the cur-rent businesses ever existed at the site, or that personal residenceswill be located where, for example, the state plans to put the highwaybridge. The document as written simply made factually based state-ments to assess the site as it exists, not as EPA might wish it wouldbe.

Comment 34. The PRP Group has no comment.

Comment 35. See the Group's response to Comment 33. EPA's com-ment on the third paragraph on page 2-6, which it is requiring to bedeleted, that the objectives in the paragraph are not in accordancewith the NCP is simply wrong. The NCP states: "EPA expects to returnusable groundwater to their beneficial uses wherever practicable,within the time frame that is reasonable given the particular circum-stances of the site. When restoration of groundwater to beneficialuses is not practicable, EPA expects to prevent further migration ofthe plume, prevent exposure to the contaminated groundwater andevaluate further risk reduction." 40 C.F.R. § 300.430(a)(iii)(F).The deleted statement is simply an elaboration of the expectation thatEPA lists in its own NCP.

Comment 36, Page 2-6, last paragraph. The Group does not objectto using the remaining criteria from the guidance for contaminants of


interest. The Group does object to the deletion of the sentence "theremedial response objective for groundwater to protect human health isto prevent future ingestion and household use of groundwater." Thatsentence accurately depicts the goal of the remedial response action,as there is no risk at the site unless groundwater is ingested in theconcentrated plume area.

Comment 37, Page 2-7. The addition of the metals chromium, lead,arsenic, and beryllium as contaminants of interest is objectionablebecause they pose no risk unless one assumes a future residential useof the O.K. Tool property. Since the State is planning to put a road-way through the portion of O.K. Tool's former property where metalsconcentration exist, residential use of the area does not constitute areasonable likely scenario as required by the NCP, but is a worst casescenario which exceeds the bounds of EPA's regulations.

Moreover, EPA objects to the use of ambient water quality criter-ia ("AWQC") because they "are appropriate for surface water, not thegroundwater." This comment ignores that the only receptor at the siteis the Souhegan River, which is a surface water body, and that conta-minants discharging into the river currently are below AWQCs (andMCL's for that matter). With treatment of the concentrated plume,those levels likely will be maintained and ultimately lowered. AWQCs,therefore, are relevant and appropriate in considering remediationobjectives at the site.

Comment 40, Page 2-8. EPA here requires the deletion of a sitespecific and regulatory analysis of the beneficial uses of the site.EPA states that the "basis of cleanup is future residential and torestore the aquifer to drinking water quality." EPA is quite correctin noting that this an area of departure between the PRP Group and thegovernment, as the use of the site for residential purposes is ex-tremely unlikely and constitutes a worst case scenario, not a reason-able maximum scenario as required by the EPA's own regulations. More-over, even if part of the area which is now used for industrial andcommercial purposes became the location of a residential development,groundwater there would not be the source of drinking water, as townwater has been extended out to the site. With no exposure pathway tothe groundwater, there can be no risks to residential property users.

Comment 41, Page 2-9. The discussion of soils contamination hasbeen revised to reflect the revised baseline health risk assessment.The conclusions remain the same as the previous draft of the Feasibil-ity Study, in that there are no contaminants of interest identifiedfor the soils at the Hitchiner or Hendrix facilities or at O.K. Tool.

Comment 42, Page 2-9, third paragraph. EPA objects to the con-clusion of its own ecological risk assessment that the onlyappropriate response for potential ecological risks would be continuedmonitoring of the site. This is simply an attempt on EPA's part to


doctor the record in such a way as to create a problem where noneexists. While there are many problems with the ecological riskassessment, its conclusion that no remedial action is required otherthan monitoring is not one of them.

Comment 42, Page 2-9, fourth paragraph and last paragraph.Details on soils removal at O.K. Tool have been provided.

Comment 43, Page 2-10, item 2. The lack of use of PCE in currentmanufacturing processes and changes in discharges from Hitchiner andHendrix are relevant to a soils discussion and should be includedhere.

Comment 44, Page 2-10 to 2-12. The changes have been made.

Comment 45, Page 2-12, second paragraph. See previous discussionin Comment 37 concerning the use of MCLs at the site as opposed toother relevant criteria. The Group has no comment on the changesrequired by the EPA.

Comment 46, Page 2-12, last paragraph. EPA has required thedeletion of the statement that "[t]he results of the baseline healthrisk assessment have not shown the discharge stream's contribution tothe underlying aquifer to pose an unacceptable risk. This statementaccurately reflected site conditions and should have remained in theFS. A copy of page 2-12 and 2-13 attached hereto as Exhibit 5.

Comment 47, Page 2-13, last paragraph. The FS has been revisedto reflect the revised baseline health risk assessment concerningambient air levels. The Group agrees with the conclusion that thereare no contaminants of interest identified for air.

Comment 48, Page 2-14. The Group has no objection to includingthe definitions of ARARs from the NCP except to the extent that thisdiscussion requires MCLs as a goal for cleanup.

Comment 49, Page 2-15. EPA has required the deletion of the dis-cussion of "source control." The FS had used the term "source con-trol" to mean a remedy at those areas where it is likely that freephase DNAPL exists at the site and are causing contaminationdowngradient of those sources. To the extent that the Group and EPAhave revised the FS to address concentrated plume areas and extendedplume areas which effectively correspond to the suspected free phaseDNAPL location, the Group has no further comment.

Comment 50. No response is required.

Comment 51. See the Group's response to Comment 42 above.

Comment 52. See the Group's response to Comment 42 and 43 above.


Comments 53 and 54. See the Group's response to Comment 42 and4 3 above.

Comment 55. See Comment 37 above concerning the Group's positionon MCLs and ARARs.

Comment 56 and 57. EPA makes a comment that DNAPLs may extendthe amount of time required for remedial activities and that MCLs maynot be achieved in the short term in the concentrated plume. Currentscientific evidence, as demonstrated by Dr. John Cherry's letters(dated December 11, 1990 and January 7, 1991 by Timothy Cosgrave) toEPA, attached as Exhibit 6, as well as EPA's own studies, indicate notonly that DNAPLs will extend the time for cleanup, but they may neverbe cleaned up in part because such sources may never be located. Tosuggest that DNAPLs may not be cleaned up only in the short term isinaccurate, without scientific justification and ignores the wholehistory of Superfund cleanup experience.

Comments 58 and 59. The Group has no comments.

Comment 60. The full quote from the NCP has been provided. TheGroup objects to the characterization of the quote in the draft FS asmisleading, since it has never been proposed by the PRP Group to onlyuse institutional controls, but to consider such controls in assessingthe risk at the site as well as for potential remedial action.

Moreover, the EPA has once again arbitrarily required the dele-tion of facts that appropriately characterize the institutional con-trols that previously have been implemented. These include: (1) run-ning water lines to businesses and residences surrounding the site;(2) the purchase of the Savage Well by Hitchiner Manufacturing; (3)the provision of alternate water supplies to the Milford Drive-Induring its use in the summer months (proposed to be implemented); (4)state regulations barring the siting of water wells at any pointtributary to the storage, treatment or use of significant amounts ofhazardous chemicals; and (5) the fact that the site is zoned forindustrial use, which excludes residential use.

The EPA selectively cites the State drinking water regulationsconcerning the casing of a well in a 100 year flood plain. It ignoresEnv-Ws 372.07 which states: "The well shall be located at least 25feet from surface waters and natural drainage ways, and not subject toa 100 year flood." Further, only where wells "must be located withina flood way" must the area immediately surrounding the well and pumpstation be built up above the 100 year flood elevation (emphasisadded). In the first instance then, the regulations themselvespreclude siting a well in the 100 year flood area.

EPA states that if the aquifer were in its "preexisting andnatural condition, a supply could be developed in the area." The EPA


statement ignores reality and represents an inappropriate approach toa site which has long been used for agricultural, industrial andcommercial operations. In fact, the Savage Well was located at thesite decades after the development of the manufacturing operations ofthe four PRPs and other commercial operations throughout the site.

Comments 62. EPA has required the statement to be included thatlocal zoning may be overturned by the zoning board of appeals. Thisis simply a misstatement of the law of New Hampshire, as zoningregulations can only be overturned by a vote of the local legislativebody, which in a town such as Milford is a vote of the whole town.

Comments 63, 64, 65, 66 and 67. The Group has no comments.

Comment 68. Sheet piling has been retained.

Comment 69. Enhanced DNAPL recovery processes have been retainedunder chemical and physical collection/treatment/discharge options.See Figure 2-3.

Comment 70. Extraction wells have been added under groundwatercontrol barriers. See Figure 2-3.

Comment 71. Solvent extraction has been retained as potentiallyapplicable for DNAPLs. See Figure 2-3.

Comment 72. No Group comment is required.

Comment 73. Solvent extraction has been retained, see Figure 2-3.

Comment 74. In-situ biodegradation has been screened out due tothe difficulty of its applicability to site-specific chlorinatedcompounds.

Comment 75. Solid waste landfill and RCRA facility have beenincluded. See Figure 2-3.

Comment 76. The alternate water supply has been deleted asrequired.

Comment 77. The technologies referenced in the comment have beenretained under physical and chemical collection/treatment/dischargeoptions. EPA asks what site conditions make DNAPLs so difficult totreat using steam or heat methods. As noted in the RI and FS, thedifficulty of locating the DNAPL sources, the DNAPLs' tendency to sinkwith the aquifer, the thickness of the unconsolidated aquifer, and thepresence of fractured bedrock, all would make DNAPL treatmentextremely difficult, if not impossible.


Comment 78 a and b. The Group has no comments as they have beenaddressed in revised Section 2.

Comment 79 through 86. The revisions to the technologies EPA haswanted retained or discussed have been made in accordance with the EPAcomments. Other than noting that these changes have been made at thedemand of EPA, the Group has no further comment on them.

The EPA's April 29, 1991 Letter to Greg Smith. Re: Comments onFeasibility Study. Chapter 3, dated February 25. 1991

General Comments:

The PRP Group emphatically disagrees with the statements that theFS as submitted did not meet the intent of the NCP or was an incorrectinterpretation of the NCP. The goal of the Superfund Program is toprevent risks to human health and the environment and to remediatethose areas causing such risks. The FS as submitted recognized thatthe only risk at the Savage Well Site would stem from the consumptionof contaminated drinking water there. Without such consumption, norisk would be (or is) present. It is an incontrovertible fact thatthere is no consumption of drinking water on a regular basis at thesite, even considering the possible seasonal use at the Milford Drive-in. An alternative water supply was proposed for the drive-in as partof the remedial alternatives discussed in the FS. Thus, there are norisks to human health or the environment at the site, as stated in theFebruary 25, 1991 draft FS.

Comment 87. The new table was provided as requested.

Comment 88. The required deletion was made.

Comment 89 and 90. EPA has taken the position that the remedialactions taken at the Savage Well Site have no bearing whatsoever onthe RI/FS process. This view is evident by EPA's removal of discus-sion concerning actions taken at O.K. Tool with respect to the removalof PCE sources (i.e., the cessation of use of PCE and removal ofsource soils and storage tanks) as well as efforts taken by Hitchinerand Hendrix, either to improve the quality of their discharges, orcease them altogether. As a result of the actions taken to date, theonly sources at the site are free phase DNAPL sources which can onlybe contained, not cleaned up. In fact, EPA's comment is concernedmore with why these actions were undertaken, rather than the fact thatthey were undertaken and could only have a positive impact onconditions at the site.

Comment 91 and 92. The PRP Group has no comment.

Comment 93. EPA has required a discussion of a possibility ofless than a thirty year monitoring program. While the group does not


object to such a discussion, it wishes to point out that it is onlyacademic because the likely presence of DNAPLs will preclude a clean-up in less than a thirty year time period.

Comment 94. The Group has no comment.

Comment 95. The Group objects to the accusation by EPA that bythe use of the word "most" before the phrase "beneficial uses" thatthe group is somehow attempting to change the intent of the NCP.

Comment 96 and 97. EPA makes the argument that the presence ofDNAPLs are unrelated to management of migration objectives. The Groupstrongly disagrees, as remedial objectives can only be relevant ifthey are made in light of existing site conditions and current scien-tific knowledge. Free phase DNAPL sources directly affect all themanagement of migration objectives and alternatives.

Comments 98 and 100. EPA makes much of the fact that free phaseDNAPL has not been actually encountered at the site and has requiredthe insertion of language to try to minimize the DNAPL issue. Theavailable evidence at the site is that free phase DNAPLs do exist,based on historical information and scientific calculation by thenation's foremost expert on DNAPLs. Given the site history, DNAPL ismore than a mere possibility as EPA has repeatedly stated, but ratheris a probability with significant implications for remediation at thesite.

Comment 99. A new figure 3-1 has been provided. EPA hasrequired the insertion of a statement that discharges to the eastern-most portion of the site could occur in the future. The basis forthis statement is that HMM lacks the information about the eastern endof the site. The same criticism holds true for EPA. EPA has little,if any, factual support to determine whether any contaminants arecontinuing to spread to the easternmost portion of the site, and if soat what concentrations (i.e., is the concentration so attenuated as tobe below MCLs?). EPA's statements are merely speculative. Moreover,containment of the concentrated plume areas likely will dissipate anyalready minimal possibility of contamination spreading furthereastward.

Comment 101 and 102. The required explanation and map changeswere made.

Comment 103. The revised text responds to EPA's comments.

Comment 104. The Group notes that it is possible that thecontaminant plume will change over time, but has no basis, and neitherdoes EPA, for saying such a change is probable.


Comment 105, last paragraph and Page 3-21. EPA's requiredchanges have been made.

Comment 106 and 107. The EPA's required changes have been made.

Comment 108. Once again, EPA has required the deletion of infor-mation pertaining to site-specific conditions that demonstrate thereis no risk to human health or the environment from current conditionsat the site, as long as no one is using the aquifer for drinkingwater. Instead, EPA simply focuses on the length of time for reme-diation of the site by natural attenuation and eliminates discussionof anything else. Moreover, EPA has arbitrarily required householdwell monitoring for residences on River Road, even though no chemicalcontamination has been detected there, and such residences aretopographically and hydrologically upgradient from the contaminationat the site. As noted repeatedly in the Group's Comments to thischange in the RI, annual monitoring is unnecessary to protect humanhealth and the environment, and therefore wastes limited funds.

Comment 109. EPA's addition focuses only on the fact that the noaction alternative would not satisfy its management of migrationobjectives. It completely ignores however, that doing nothing at thissite would not present a risk to human health or the environment undercurrent site conditions and thus is a viable alternative by itself.

Comment 110. Cost tables, and discussion have been revised inaccordance with EPA comments and discussions with Group members andHMM Associates Inc.

Comment 111. Once again EPA has exalted form over substance. Itdoes not matter in the least whether institutional control measureshave been taken as a result of the RI/FS process, or simply inresponse to contamination at the site. What matters is that theyalready exist at the site and include and are not limited to thefollowing: institutional and commercial zoning; alternate publicwater supply to the area; purchase of the Savage Well by a privateparty; State law limitations on the siting of a well supply in alocation such as the Savage Well aquifer. Moreover, the Group hasoffered to restrict its own use of groundwater on properties it owns,as well as purchase drinking water rights elsewhere in the aquifer.

Comment 112. The logic of the two EPA-required sentences isflawed. EPA states that because this alternative does not reduce thecontaminants on site, but allows for natural attenuation, the longterm effectiveness is considered low. On the contrary, if the con-tamination naturally attenuates over time, the long term effectivenessis high, and the clean-up in the dissolved plume will occur over time.

Comment 113. EPA has required the deletion of a paragraphstating that alternative MM-2 would be easily implemented because the


existing monitoring wells would make monitoring simple. The PRP Groupbelieves that the original text should have remained in the FS.

Comment 114 - 116. The PRP has no comments.

Comment 117. The PRP Group has made EPA's required changes.

Comment 118 and 119. The PRP Group has made EPA's requiredchanges to the figures for the alternatives.

Comment 120 - 123. The biological alternative has been revisedat EPA's direction to be included in one alternative only, rather thanassessed for each of the alternatives. Concerning EPA's comment 122,which required the insertion of a paragraph stating that the effec-tiveness of alternative MM-3A is considered low to moderate, thisalternative, with recovery wells at O.K. Tool and Hitchiner, capturesthe concentrated plume in the area of the suspected DNAPL sources. Tocapture the concentrated plume will allow the extended plume to beremediated to MCLs through natural attenuation. Thus, theeffectiveness is high.

Comment 124 and 125. The Group points out that EPA has requiredthe deletion of all alternatives other than pump and treat alterna-tives. The Group had included other alternatives as a way to try toreduce the outrageous costs of remediation.

Comment 126 - 130. EPA has objected to the use of alternativeconcentration limits equivalent to the ambient water quality criteriafor groundwater discharged to the Souhegan River. Such an objectionis without merit and lacks legal authority.

Comment 131 - 132. The PRP Group has deleted those alternativesEPA has required to be deleted.

Comment 133 - 138. The Group once again disagrees with EPA'sanalysis of the ACL issue as well as its required comments that treat-ment of the concentrated plume area is not sufficiently protective ofhuman health or the environment with respect to downgradient areas.Thus, once again, long term effectiveness is not low, as EPA hasclaimed, but rather is high because the extended plume will remediateitself.

Comment 139 - 143. The PRP Group has indicated, as EPA hasdirected, the appropriate capture zones in the various alternatives.EPA has stated that it wanted a discussion of the effectiveness of thealternatives with respect to the Souhegan Valley Fish Hatchery andprotectiveness to the river. As EPA is already well aware, no detec-table contamination exists in the river, and the slight amount of con-tamination found at the Souhegan Valley Aquaculture facility is belowMCLs. It follows, therefore, that when treatment of the concentrated


plume occurs, the so-called impact to the river and fish hatchery willbe lessened from its already non-existent level.

Comments 143 - 150. The PRP Group has made the required changesto show what sections of the plume will not be captured by pumpingwells in the extended plume. The Group also points out that EPA hasdetermined what level of effectiveness each alternative will have andin this case has chosen the phrase "moderate," but has not said moder-ate as opposed to what level or standard. As stated in the previousparagraph, any of the alternatives protect the Souhegan River andSouhegan Valley Aquaculture facility, which are not being impacted bycontamination in the first instance. EPA makes the unwarranted leapin logic that only by pumping and treating the entire aquifer andcontaminant plume can the alternative be said to protect human healthand the environment. This approach completely ignores the riskassessment, as well as EPA's own environmental risk assessment, whichdemonstrates that there is no risk to the site as long as no one isdrinking the groundwater, which is the current and reasonablyforeseeable future situation.

Comment 151. The PRP Group has grouped the alternatives as EPAhas required and identified the "representative" samples designated byEPA to be discussed in the detailed analysis of alternatives. TheGroup points out that EPA has chosen for its "representative"alternatives the most expensive alternatives out of each group.

Comment 152. The additional EPA-required alternatives have beenincluded. As arbitrarily directed by EPA without any supportinganalysis, the effectiveness of each alternative, MM9, 10 and 11, isdesignated moderate, high and high, respectively, whether that isaccurate or not.

April 29. 1991 EPA Comment Letter re; Feasibility Study Review ofChapter 4.

Comment 153. The PRP Group has made the required changesdistinguishing between "free phase DNAPL" and DNAPL.

Comment 154. EPA comments generally that there is too much useof "evaluative wording", like one alternative costs more than theother. It complains that comparison of alternatives should have beendone in Section 3 of the FS. The detailed analysis cannot properlyoccur if there is no comparison among the alternatives being analyzedin detail. Despite EPA's reliance on a quotation from a footnote in aRI/FS guidance document that was never put out for public comment, theformat of Section 4 was proper under the NCP and CERCLA.

EPA also complains that the group used sentences indicating thatARARs may be met, instead of ARARs must be met. In light of the site-specific conditions at the Savage Well Site, it is not scientifically


possible to achieve ARARs. Accordingly, ARARs may be met, or they maynot be met. In instances where they may not be, CERCLA provides amechanism for waiving ARARs. Moreover EPA's general comment overlooksthe paragraph at the top of Page 4-7 in the Draft FS which states thatoverall protection of human health and the environment in compliancewith ARARs "constitute threshold criteria which must be met by anyselected remedy."

EPA states that "there will be a removal of or cleanup of soil"at OK Tool. This declaration is erroneous. EPA's own preferredremedy recognizes that there is no necessity for cleanup of soilanywhere at this site, given that groundwater is the only medium ofconcern.

Finally, EPA states that for each alternative the group must makeclear which portion of the aquifer is allowed to naturally attenuateor "dilute itself into the environment." The Draft FS has alwaysstated that a certain portion of the plume will be allowed to reme-diate itself or naturally attenuate under certain alternatives. Thegroup, however, has made the changes in response to EPA comment.

Comment 155, Page 1-4, 2nd Paragraph. EPA has required thedeletion of the paragraphs specifically identifying where DNAPLexists, and where it possibly exists. The deleted paragraph isincluded here and should have remained in the FS:

The detailed analysis recognizes that the plume of contami-nated groundwater is persistent because of the existence ofseparate phase liquids, i.e., dense non-aqueous phaseliquids (DNAPL), below the water table of the OK Tool pro-perty. The existence of DNAPL has been deduced from aconvergence of information including: historical materialsmanagement practices; concentration of dissolved chlorinatedhydrocarbons in groundwater immediately downgradient from OKTool and in the groundwater sampled in the bottom of thesource-removal excavation on the OK Tool property; and cal-culations based on the soil concentration of chlorinatedhydrocarbons measured in the excavations during source remo-val at OK Tool. Although the source(s) of the chlorinatedhydrocarbons as defined by the EPA and as generally per-ceived by the public have been removed, residual volumes ofthese compounds have migrated vertically from the source(s)to areas below the water table. These DNAPL now remain asaccumulations in the unconsolidated deposits and perhaps inthe bedrock. Continued dissolution of the DNAPL hasresulted in the persistent concentrations of dissolvedchlorinated hydrocarbons that have been measured downgra-dient of OK Tool. In addition, limited areas of persistent-ly elevated concentrations of dissolved chlorinated hydro-carbons at Hitchiner and in the vicinity of MW-20 are con-


sidered in the analysis as concentrated areas of the plumewhich may result from the presence of DNAPL below the watertable, and therefore require specific attention. Theremainder of the dissolved-contaminated plume is consideredin the analysis as an extended plume of dilute contaminatedgroundwater in a highly permeable unconsolidated andunconfined aquifer.

EPA's designated replacement for that paragraph is a bland, non-location-specific explanation of DNAPLs which, while generallyaccurate, does not precisely depict the state of information withrespect to contamination at OK Tool as opposed to the remainder of theaquifer.

Comment 156, Page 1-4, 3rd Paragraph. EPA has required thedeletion of the statement that "no measurable concentrations ofchlorinated hydrocarbon solvents, however, have been detected in theSouhegan River." Once again EPA has arbitrarily required the deletionof a statement of fact and instead inserted a speculative argument notsupported by any of the site data, which states that groundwater atthe eastern and southeastern portions of the site may eventuallydischarge to the river at some location downstream and east of thesite. The self-evident uncertainty in EPA's own language demonstratesthe speculative nature of the entirely unsubstantiated "conclusions"contained in its required insertion.

Comment 157, Page 1-4, 4th Paragraph. The group has previouslyprovided comments to the EPA on the folly of considering residentialuse at the site for risk assessment purposes. (See Comment 40,above.) The group incorporates by reference herein those comments.Nonetheless, no future use conditions of the site require managementthrough active source control.

Comment 158, Pages 4-2 and 4-3. EPA has required the deletion ofboth pages. Those pages present a detailed discussion of the institu-tional controls that have been handled or will be implemented at thesite. In addition the paragraph on Page 4-2 identifies the alterna-tive that performs most effectively on a cost and environmental basisfor the site. Copies of these two pages are attached hereto and in-corporated in by reference. (see Exhibit 7.) They should not havebeen deleted.

Comment 159, Page 4-4, first paragraph. EPA has required thedeletion of the following: "the overall presentation of alternativesin the detailed evaluation will be based on the understanding that aminimum remedial plan for this site would consist of extraction andtreatment of contaminated groundwater migrating from the concentratedareas of the plume and that, given the nature of DNAPLs, this compo-nent of the remedial alternative will continue to operate for an in-definite period of time. Given the recovery and treatment of contam-


inants in the concentrated areas of the plume, contaminants in thebalance of the aquifer will over some period of time become reduced toacceptable levels due to natural flushing. The containment, removal,treatment or disposal of soils and sediments.

Comment 160, Page 4-4, second paragraph. The PRP Group hasrevised the paragraph to list the representative alternatives beingdiscussed in Chapter 4, in accordance with EPA's directive.

Comment 161, Page 4-6. EPA has required the replacement of thedefinitions of the nine criteria by which each alternative is to bejudged with its own definitions. Apparently, EPA does not sanctionuse of its own RI/FS guidance document, which the FS quoted, indefining each of the criteria. See pages 4-6 to 4-9 attached heretoas Exhibit 8. EPA apparently only wants its regulations to mean whatit says they mean when it's convenient for EPA. Over objection, EPA'srequired changes in the definition of the criteria have been made.

Comment 162, Page 4-9, 4th paragraph, Page 4-25 and 4-45. ThePRP group has no response to this comment at this time.

Comment 163, Page 4-10, First Paragraph. The text has beenrevised to indicate where the streamline figures are analyzed anddepicted.

Comment 164, Page 4-11, First Paragraph. The requested changehas been made.

Comment 165, Page 4-11. The group has no comment on EPA's re-quired sentence that the development of contaminant concentrations didnot account for biodegradation of PCE to a chemical with a lowerretardation factor which results in a conservative estimate ofconcentrations.

Comment 166, Page 4-13. EPA states that the source control al-ternatives cannot be finalized until the issue of chromium and arsenicand PCBs are addressed. The Group incorporates by reference the June28th report of Environmental Science and Engineering indicating thatchromium is not a problem for the groundwater at the site. (seeExhibit 9.)

Comment 167, Page 4-14. The Group will respond to EPA's requiredARARs changes as they are provided to the Group.

Comment 168, Page 4-14. Long-term effectiveness. The long-termeffectiveness of the SC-1 alternative correctly notes that any resi-dual contamination in soils and sediment does not pose a threat tohuman health or the environment in light of current site uses. Thesource control alternative therefore would not require any treatmentof soils and sediments. Nevertheless, there already has been soils


removal action undertaken at OK Tool. Plus, the source control whichnormally would be evaluated under this alternative (i.e., removal ofPCE discharge sources) has already been performed. The source controlalternative, therefore, should state that it does not involve anyfurther containment, removal, treatment or disposal of soils andsediments.

Comment 169, Page 4-15. EPA has required the deletion of thefirst paragraph on this page because it uses the phrase "remedialaction in reference to source removal at OK Tool and modifications ofdischarges at Hitchiner and Hendrix." EPA cavalierly states thatthese activities have nothing to do with the remedial action at thesite. On the contrary, these actions have everything to do with theremedial action at the site, as the soil removal at OK Tool hasremediated a potential source of contamination of groundwater at thissite, and the modifications of discharges at Hitchiner and Hendrixaffect the contents of the discharge stream. All of these activitiesare highly relevant to the determination of the need for furtheractivity at the site.

Comment 170, Page 4-15, Fifth Paragraph. No response wasrequired.

Comment 171, Page 4-17, Table 4-3. The PRP Group disagrees withthe statement that costs for sampling are excessive. Sampling isexpensive.

Comment 172, Page 4-18, First Paragraph. The PRP Group disagreeswith EPA's required change, revising the paragraph to state that theconcentrated plume "may be persistent" rather than "is persistent."Whether or not free phase DNAPL has been specifically encountered atthe site, the country's foremost expert in DNAPL has determined thatthere is DNAPL at OK Tool. EPA's wishful thinking that there is notDNAPL ignores the only relevant evidence in the administrative record,which happens to be to the contrary.

Comment 173, Page 4-18, Third Paragraph. The EPA's requiredchange has been made and commented upon previously.

Comment 174, Page 4-18, Fifth Paragraph. EPA has required thedeletion of this paragraph. Among other statements, this paragraphnoted that given site characteristics, available alternatives for therecovery and treatment of DNAPL are limited: "The principal approachis groundwater extraction and treatment to prevent migration ofcontaminants to downgradient portions of the aquifer." The remainderof this paragraph discussed alternative ways to achieve this desiredobjective in a more effective and cost-efficient way. The paragraphshould have remained in the FS. A copy of page 4-18 is attachedhereto as Exhibit 10.


Comment 175, Page 4-19, Second Paragraph. Where appropriate,assumptions have been deleted as EPA has directed.

Comment 176, Page 4-19, Third Paragraph. EPA has required thedeletion of this paragraph which deals with the biological treatmentalternative. The PRP Group has previously commented on EPA's requiredchange on the biological alternative, and incorporates those commentsherein by reference.

Comment 177, Page 4-19, Fourth Paragraph. The paragraph has beendeleted in light of the changes to the alternatives to be evaluated inthe detailed analysis by EPA.

Comment 178, Page 4-19, Fifth Paragraph. EPA has required thedeletion of this paragraph, claiming it is another example ofrepetition "ad infinitum". That paragraph stated as follows:

"Assuming the effective recovery and treatment of the con-taminants presently migrating from the concentrated plumeDNAPL areas, the balance of the aquifer will be availablefor beneficial uses and will over time achieve target clean-up levels due to reduction in contaminants by natural flush-ing. The evaluation considers whether the significantlyincreased costs of treatment of the extended plume result ina substantial increase in protectiveness or in a substantialreduction in the time to achieve clean-up levels in thebalance of the aquifer over that provided by treatment ofthe concentrated plume coupled with institutional controlsover the balance of the contaminated aquifer."

That paragraph is an accurate reflection of what the feasibility studyin this case should be performing. EPA's objection to performing acost benefit analysis with respect to alternatives requiringincreasingly aggressive levels of pumping is without legal orpractical foundation.

Comment 179, Page 4-20, First Paragraph. EPA has once againselectively and arbitrarily required the deletion of a paragraphsetting forth the history of this site necessary to place the noaction alternative in appropriate perspective. The paragraph setforth all the remedial actions taken at the site already, and analyzedexisting site conditions. The paragraph should have remained in thedocument. A copy is attached hereto as Exhibit 11.

Comment 180, Page 4-20, second paragraph. EPA has required theinsertion of a statement that the sampling program would includeperiodic sampling of household drinking water wells north of theSouhegan River. The group has previously responded to EPA's requiredinsertion of this sampling requirement, and incorporates thoseobjections here. Since the alternative MM-1 sampling will be carried


through all the other alternatives, EPA is arbitrarily and unnecessar-ily adding to the cost of what is already an exorbitantly costlyprogram at this site with absolutely no factual basis for theaddition.

Comment 181, Page 4-21. EPA objects to the conclusion that pro-tection of human health and the environment has already been achievedat the site by activities completed to date. That conclusion is cor-rect, whether or not additional institutional controls are imposed atthe site. It is not sufficient for EPA to claim that simply becauseno institutional controls are included in this alternative, the siteis not protective of human health and the environment. Since no oneis using the groundwater at the site, there is no risk posed, regard-less of the presence or absence of institutional controls.

Comment 182, Page 4-21, Second Paragraph. See the Group'sresponse to Comment 181. EPA has required the deletion of the Group'sparagraph concerning overall protection of human health and theenvironment and has inserted its own paragraph. The group's paragraphis incorporated herein by reference and attached as Exhibit 12.

Comment 183, Page 4-21, Last Paragraph. EPA has required thedeletion of the feasibility study's paragraph concerning long-term andperiodic monitoring and this alternative. EPA has required the in-sertion of its own paragraph which includes a statement that there isno long-term protectiveness under this alternative. For the reasonsstated previously, the Group vehemently disagrees with EPA's conclu-sion in this regard. The group's paragraph is incorporated herein byreference and page 4-21 attached as Exhibit 12.

Comment 184, Page 4-22, First Paragraph. EPA has required theinsertion of a paragraph stating that contaminated groundwater wouldcontinue to migrate downgradient beyond the existing study area. EPAalso states that the volume of contaminated groundwater would continueto increase and the alternative would not result in any immediate orforeseeable reduction in toxicity, mobility or volume of contaminants.Once again, the Group disagrees with EPA's conclusions. EPA's state-ments are unsupported by site evidence and are merely speculative.There is no evidence that the volume of contaminated groundwater wouldincrease, or that the groundwater would do anything but harmlesslydischarge to the Souhegan River.

Comment 185, Page 4-22, Second Paragraph. EPA has required theinsertion of the sentence that no action provides no additional short-term control measures for protection against use of the groundwater asa drinking water source. In reality, no further protection is needed,since a public water line runs out beyond the site. No one currentlyuses the aquifer for drinking water purposes, nor would anyone havereason to do so in light of the available public water supply. EPA'srequired sentence once again selectively ignores actual conditions at


the site. EPA has also required the addition of a sentence statingthat human receptors and wildlife that traverse this site in thefuture may be exposed to contamination if groundwater discharges to asurface water body. This statement gives the incorrect and misleadingimpression that groundwater discharging to surface water poses a riskat this site. The testing of the Souhegan River during the RI doesnot indicate any such risk, and in fact there were no chemicalsdetected in the river. Moreover, the suspected possibility that theremay at times be discharges to the Hitchiner or Hendrix dischargestream has not been shown to pose any risk to human receptors orwildlife. EPA's statement is simply inaccurate and without support inthe record for this site.

Comment 186, Page 4-22, Fourth Paragraph. EPA has required aparagraph to state that additional monitoring wells could be installedif the site is determined to be extending beyond the existing studyarea. The Group disagrees with EPA's proposal to have a never-endingstream of monitoring wells required at this site. Once the concen-trated plume area is addressed, the rest of the plume will remediateitself.

Comment 187, Page 4-22, Last Paragraph. See the Group responseto Comment 186.

Comment 188, Page 4-23, Table 4-4. The Group disagrees withEPA's assessment that the cost for sampling is excessive. HMMAssociates, Inc. has revised its cost estimates in light of EPA'scomments and those revisions are included here. See HMM letter toEPA, dated April 29, 1991, which is incorporated herein by reference.(See Exhibit 13.) These costs reflect real-world charges by competentlaboratories with acceptable QA/QC procedures and a reputation foraccuracy and honesty.

Comment 189, Page 4-24, First Paragraph. EPA has required thedeletion of sentences stating that currently employed institutionalcontrols would be augmented by purchase of groundwater rights in theareas of the site containing VOC's above the target clean-up levels.In addition, EPA has required the deletion of the sentence saying thatmuch of the contaminated portion of the aquifer is currently usablefor industrial and agricultural purposes. These statements arestatements of fact which should remain in the description of alterna-tive MM-2. EPA's claims that they have no support in the RI or FS butsuch a claim is without merit.

Comment 190, Page 4-24, Second Paragraph. EPA has required thedeletion of this paragraph. This paragraph described a proposedsampling and long-term monitoring plan. EPA has instead required theinsertion of a generalized statement that there would be more long-term monitoring than the no action plan. EPA has provided norationale for this change and there likely is none. The deleted


paragraph is incorporated herein by reference and a copy of page 4-24is attached hereto as Exhibit 14.

Comment 191, Page 4-24. EPA has required the deletion of twomajor work items and the replacement of those work items with languagethat it has developed. EPA has stated that the institutional controlscan include the provision of alternative water supply for residentialwells north of the river, but the Group must state once again that thesite has posed no threat to those wells and such institutional con-trols would not be required or necessary. The deleted work terms areincorporated herein by reference. See Exhibit 14.

Comment 192, Page 4-25. EPA has required the deletion of theparagraph concerning overall protection of human health and the envi-ronment and replaced it with one of its own wording. Once again, itmakes the erroneous claim that except through institutional controls,alternative MM2 would not contribute to the protection of human healthand the environment. Once again, EPA's conclusion is incorrect.Since no contaminated groundwater would be ingested under this alter-native there could be no risk to anyone at the site. The deletedparagraph is incorporated herein by reference and a copy of page 4-25is attached hereto as Exhibit 15.

Comment 193, Page 4-25, Compliance with ARARs. EPA has requiredthe deletion of a sentence stating that the limited action alternative"provides for an alternative water supply and institutional controlsto prevent the future use of the aquifer for drinking water purposes."There is no reason to delete that sentence and it should have remainedin the FS.

Comment 194, Page 4-25, State ARARs have been included in theARARs Table as required by EPA.

Comment 195, Page 4-25, Third Paragraph. EPA has required theaddition of the phrase that AWQC "may be maintained over time" in thetext. The Group has made this change.

Comment 196, Page 4-26. The PRP Group has added the phrase "anddeed restrictions" at the end of the first sentence as EPA hasrequired. EPA has also required the addition of a statement that thealternative is not effective because groundwater eventually maymigrate downgradient of the study area in concentrations above clean-up levels. Once again, EPA is engaging in unsubstantiated specula-tion. This sentence is without any factual basis and should not havebeen added to the FS.

Comment 197, Page 4-26. The PRP Group has no comment on therequired change.


Comment 198, Page 4-26. See the Group's responses to EPA comment185, which responses are incorporated herein by reference and areequally applicable to EPA's required additions in this instance.

Comment 199, Page 4-26. EPA has arbitrarily required the addi-tion of a paragraph stating, among other things, that alternative MM-2will allow contamination to migrate in the groundwater and increasethe overall level of response necessary to monitor an expanded area ofcontamination. EPA's required addition is without substantiation, andignores the fact that even if the plume were to expand, the eastern-most end of the plume would be so dilute as to be below MCLs and wouldnot pose any threat to human health or the environment. The Groupaccordingly objects to EPA's required insertion of these statements.

Comment 200, Page 4-27, Last Paragraph. See the Group's responseto Comment 187 above, which comments are incorporated herein byreference.

Comment 201, Table 4-5, Cost estimates for alternative MM-2, hasbeen revised in accordance with discussions between EPA and HMM Asso-ciates, Inc. to reflect EPA's required reduction in sampling pointsand costs.

Comment 202, Section 4.4.3. EPA states that alternative MM-3should be screened out in chapter 3 because it is not protective ofhuman health or the environment, although EPA does allow the Group tobring this alternative forward in the detailed analysis. EPA is wrongin stating that MM-3 does not provide protection to human health andthe environment. In fact, MM-3 is the only remedy that is required atthe site. It would treat the concentrated areas of the plume, whichwould arrest the continued contamination of the aquifer, and allow theremaining portions of the aquifer to naturally attenuate. Not onlywould this alternative be the most cost effective for the site if UVoxidation technology is used, but the slightly longer treatment timesfor the extended plume would more than be made up by the cost savingsof using this alternative. Alternative MM-3 is the appropriate remedyfor this site, given site conditions.

Comment 203, Figure 4-2. EPA requested an explanation of thestreamlines shown on this map. HMM Associates should have providedone if one was necessary.

Comment 204, Page 4-29. EPA has requested a statement in thetext giving the estimate for future use of the aquifer for industrialwater purposes. That information was contained in the RI.

Comment 205, Page 4-36. The PRP Group has no comment and hasadded the sentence that if free phase DNAPL is recovered it would beexpected that the DNAPL would be separated out in the surge tank.


Comment 206, Page 4-36. The PRP Group has made the change tostate that TCA concentrations will be below 200 mg/1.

Comment 207, Page 4-38. EPA states that dilution is not an ac-ceptable remedy but that comment has no place in a review of alter-native MM-3 where there would be pumping and treating of contaminatedgroundwater at OK Tool and Hitchiner. Accordingly, the Group has nofurther response to EPA's erroneous comment.

Comment 208, Page 4-39. In accordance with the agreement betweenthe PRP Group and EPA, the Group has deleted all references to theconstructed wetlands alternative in section 4 of the FS. In light ofthis agreement, no further comment is required in response to EPA'scomments on the biological alternative.

Comment 209, Page 4-45. EPA claims that in evaluating MM-3 theGroup is not following the NCP or guidance documents. In particular,EPA claims that institutional controls can only be used when activerestoration of the aquifer is not possible. EPA misinterprets theNCP. The NCP states that "EPA expects to use institutional controls. . . to supplement engineering controls ... to prevent or limitexposure" to contamination at the site. 40 C.F.R. § 430(iii)(D).Thus, institutional controls must not be evaluated in light of whetheractive restoration is possible or not, but instead are part of acomplete remedy in addition to engineering controls such as treatmentof the contaminated plume. This is exactly what MM-3 offers.

Moreover, EPA asks the rhetorical question whether activerestoration is practicable at this site. It quotes a portion of thepreamble to the March 1990 NCP which states "natural attenuation isgenerally recommended only when active restoration is not possible,cost effective or warranted because of site specific conditions."This is precisely the situation we face at the Savage Well Site. Thepresence of DNAPL, which EPA refuses to admit despite the testimony ofthe foremost authority in the country, precludes active restoration ofthe concentrated portion of the site. Moreover, a comparison of theestimated treatment times for the extended plume for MM-3 andalternative MM-11A indicate that the former is twenty-five to ninetyyears and the latter is fifteen to sixty. When EPA considers thevastly increased costs of MM-11A, $23-29 million (assuming fourpercent inflation) the majority of which is caused by the unnecessarydowngradient wells, the choice to any reasonable mind is clear. EPA'scomments are without merit.

Comment 210, Page 4-45. The section dealing with the overallprotection of human health and the environment has been revised toindicate the mass of contamination removed, and the effect on theextended plume, as well as the effect of the combination of treatmentand institutional controls. The section properly concludes that MM-3would provide a high level of protection.


Comment 211, Page 4-45. The FS has been revised to reflect theEPA required changes concerning compliance with ARARs.

Comment 212, Page 4-46. The Feasibility Study has been revisedto address the EPA comments concerning the long-term effectiveness ofthis alternative. Discussion of both the concentrated plume and theextended plume as well as treatment times for each have beenclarified.

Comment 213, Page 4-46. The PRP Group has no comment.

Comment 214, Page 4-47. EPA has required discussion of theestimated time for achieving drinking water standards in the diluteplume. This discussion has been added.

Comment 215, Page 4-48. The cost tables have been adjusted inaccordance with discussions between EPA and the Group.

Comment 216. No Group response is required.

Comment 217. EPA did not have a comment 217.

Comment 218, Page 4-58, Table 4-11. EPA has raised a number ofissues concerning the costs used in EPA's estimated work costs. SeeHMM's letter concerning costs dated April 29, 1991. EPA has asked toreceive a justification for two treatment plants. Two treatmentplants are proposed because of the different types and concentrationsof contamination located at OK Tool as opposed to Hitchiner. (OK Toolis treating primarily PCE and Hitchiner is treating primarily TCA.)

Comment 216, Page 3-62. Alternative MM-3C has been screened outin Chapter 3, as EPA has required.

Comment 217-219. EPA has required the screening out of MM-3C andMM-3D, so there is no need to address these comments, except to notethat the change was mandated by EPA.

Comment 220-224. EPA has required the screening out of MM-4 inChapter 3 so there is no need to respond to EPA's comments on thediscussion of this alternative in Chapter 4.

Comment 225, Page 4-96. EPA is concerned that the statement inMM-5 indicates that portions of the extended plume would not achieveARARs as a result of natural flushing. EPA makes the accusation thatMM-3 and 4 were "a hoax." A more likely explanation is a simple errorin draftsmanship rather than any hoax. The Group has always main-tained that treatment of the suspected DNAPL areas would result inalternative MM-3 allowing the extended plume to flush itself cleanover time. One inadvertent phrase on page 4-96 does not change thatconclusion.


Comment 226, Page 4-126. EPA has required the addition of thesentence "The 5 ug/1 corresponds to the MCL clean-up level." The PRPGroup has no comment.

Comment 227, Page 4-138. EPA has required the deletion of theCost Sensitivity Analysis from the FS itself, and instead required itsplacement in an appendix. The Group strongly believes that the CostSensitivity Analysis should be up front in the text of the document,rather than as an appendage to it.

Comment 228-230, Page 4-147. EPA has required the completerevision of Section 4.6 of the FS which is the Comparative Analysis ofAlternatives. Rather than outline each point of difference betweenthe initial text and the revised text, we attach a copy of the entiredraft section and incorporate it herein by reference see Exhibit 16.

May 16, 1991 EPA Comment Letter on ARARs for Chapter 2

The Group has no further comment on the changes required by EPAto be made.

The EPA also provided additional general comments on Chapter 2 inlight of the revised Section 2 which was submitted to EPA under coverletter of May 24, 1991. The general comments were organizationalrather than substantive and therefore require no response.

May 17. 1991 EPA Comments on the Feasibility Study

The PRP Group has no comments on the EPA's required changes onthe ARARs tables found in Chapter 2.

June 13, 1991 EPA comments on revised chapters 1 and 2 datedMay 24, 1991 and additional comments on ARARs

Comments 1-5. The Group has no comments on EPA's requiredchanges.

Comment 6. The EPA "conservatively" assumes that chromium existsat the site in its hexavalent state. The PRP Group submitted an ana-lysis of the chromium situation at O.K. Tool by letter dated June 28,1991 which concluded that it was unlikely that hexavalent chromiumexisted at O.K. Tool but rather that chromium existed in its trivalentstate. (See Exhibit 9.) While EPA's required changes addressingchromium indicate that the hazard index is at an acceptable level, thefinal FS should accurately reflect the most recent analysis ofchromium at the site.

Comment 7 and 8. The PRP Group has no comment.

Comment 9. The PRP Group agrees with the change.


Comment 10 - 16. The PRP Group has no comments.

Comments 18 - 23. The Group has no comments.

Comments 17, 24, and 25. The PRP Group objects to the use ofNCLs at the Savage Well Site as target clean-up levels because suchlevels do not comport with knowledge of site conditions. The presenceof DNAPLs at the site means that discharge from those sources willlikely be present for an indeterminant amount of time and make clean-up in the concentrated plume virtually impossible. The use of MCLsfails to take into account the site-specific conditions present at theSavage Well Site.

The Group has no other comments on the ARARs changes EPA hasrequired to be made at this time.

The EPA's June 18. 1991 Letter to Gregory Smith Regarding Reviewof Chapter 4, June 5, 1991 Revisions and New Hampshire AttorneyGeneral Comments on State ARARs

Comment 1, Page 4-2, fourth paragraph. The PRP Group has nocomment.

Comment 2, Page 4-22, Section 4. EPA has required the insertionof the following sentence: "Each pump and treat alternative will alsoinclude the understanding that periodic evaluations of the state-of-the-art remediation techniques for concentrated plume/free phaseDNAPLs and implementation of those techniques which may be success-ful." The PRP Group vehemently objects to the insertion of this lan-guage. By this sentence, EPA is simply trying to write itself a blankcheck at the PRPs' expense to evaluate an unspecified number ofunknown technologies that may be developed in the future. Thepotential consequences of such unlimited language could be devastatingfor the PRPs. The added sentence should be deleted and EPA shouldlimit itself to the 5 year review provided in CERCLA Section 122(C).

Comment 3, Page 4-25, second paragraph. EPA states that if freephase DNAPL is present in the concentrated plume area, the timeframefor remediation cannot be estimated. It then goes on to make an es-timate that remediation would be in excess of 100 years. EPA's state-ments are blatantly inconsistent. Moveover, EPA has required the in-sertion of language that the no action alternative is not protective.This simply is a misstatement of fact, as EPA's own statements at thePublic Meeting on July 11, 1991, have admitted. There is no riskeither to human health or the environment under existing siteconditions. EPA should change its inaccurate statements.

Comment 4, Page 4-26. The PRP Group has no comments on therequired changes.


Comment 5, Page 4-27, first paragraph. The PRP Group has nocomment on the required change.

Comment 6, Page 4-29, first paragraph. The PRP Group has nocomment on the required change.

Comment 7, Page 4-30. The PRP Group has no comment on therequired change.

Comment 8, Page 4-31, first paragraph. See the Group's responseto comment 3, above.

Comment 9 - 12. The PRP Group has no comment on the requiredchanges.

Comment 13, Page 4-25. See the Group's response to comment 1,above, concerning scheduled evaluations of state-of-the-artremediation techniques for free phase DNAPL areas.

Comments 14 and 15. The PRP Group has no comments on therequired changes.

Comment 16, Page 4-51. EPA has required the deletion of thefollowing: "the groundwater within the concentrated plume may neverattain federal and/or State MCLs due to the likely presence ofDNAPLs." Instead, EPA requires the insertion of statements thatassume that DNAPLs do not exist and the MCLs will be met in theconcentrated plume. These statements are contrary to site evidence,contrary to the opinion of the nation's foremost expert on the issueof DNAPLs, and are otherwise arbitrary. In fact, the deletedstatement was included in response to EPA's own directive to statewhether ARARs would be met in the concentrated plume areas. EPA hasrequired the deletion of an accurate clear statement, and insteadinserted language which merely obfuscates the concentrated plumeissue.

The Group does, however, agree with the phrase that EPA isinserting that the ARARs may have to be waived in the concentratedplume areas.

Comments 17 and 18. The PRP Group agrees with the change thatambient water quality criteria are currently being met in the SouheganRiver and that this criteria will continue to be satisfied. The Grouphas no comments on the remaining changes in these two comments.

Comment 19. The PRP Group has no comment on the required changesEPA wants inserted. The Group does note, however, that the financialimpact to the local community could be adverse unless EPA agrees tofund a significant portion of the remedy.


Comment 20, Page 4-57. The PRP Group has no comment on therequired changes.

Comment 21. See the Group's response to comment 2 above.

Comments 22 - 27. The PRP Group has no comments on the requiredchanges.

Comment 28, Page 4-66. See the Group's response to comment 3above.

Comment 29. The PRP Group sees no substantial difference betweenthe existing text and EPA's required changes and therefore has nocomments.

Comments 30 - 32. The PRP Group has no comment to the requiredchange. See also the Group's response to comment 19 above concerningthe potential impact on the community.

Comments 33 and 34. The PRP Group has no comment on the requiredchange.

Comment 35, Page 4-72. See the Group's response to comment 2above.

Comments 36 and 37. The PRP Group has no comments on therequired change.

Comment 38, Page 4-73. EPA has required the deletion of thestatement that the groundwater plume will dilute itself into theenvironment in the extended plume area. Once again, EPA has requiredthe deletion of an accurate statement of fact which should remain inthe FS.

Comment 39. The PRP Group has no comment on the requiredchanges.

Comment 40. See the Group's response to comment 3 and comment 16above.

Comment 41. See the PRP Group's response to comment 29 above.

Comment 42 - 71. Each of the EPA required changes in thesecomments have been addressed in the responses to comments 1-41, above.The PRP Group incorporates its responses to EPA's correspondingcomment.


EPA Letter to Gregory H. Smith, Dated June 19. 1991 RegardingAdditional Language to be Inserted Into Chapter 4 of theFeasibility Study and Addendum

EPA has required the insertion of language and alternatives MM-3,7, 9, 10 and 11 to the effect that these alternatives will includeconstruction of a discharge pipe or structure at the Souhegan River orprocess discharge stream which will have limited if no inconsequentialimpact to the immediate environment. The PRP Group has no furthercomment on the EPA's required language, except to note that it wasmandated by the agency.

EPA Letter to Gregory H. Smith, Dated June 19, 1991 RegardingComments on June 5, 1991. Revisions to the Feasibility StudyChapter 3

Comment 1, Page 3-5. EPA has required a change in a discussionof the Baseline Health Risk Assessment for exposure to soils, andrequired the two paragraphs appearing in the revised draft of the FSSection 3 to be replaced by three areas. EPA has required thedeletion of an accurate clear statement, and instead inserted languagewhich merely obfuscates the concentrated plume issue.

The Group does, however, agree with the EPA required phrase thatARARs may have to be waived in the concentrated plume areas.

New Hampshire Attorney General's Comments on ARARs by Letterdated May 31. 1991 to Richard Goehlert

Charles B. Holtman, Assistant Attorney General, provided a listof statutes and regulations which the State believes may be ARARs forthe site. Because these simply are a listing of statutes and regula-tions, it is virtually impossible to state which statutes or regula-tions are potentially applicable, or relevant and appropriate. Accor-dingly, the ARARs will be evaluated in the ARARs appendix to the FS.

EPA Letter to Gregory H. Smith. Dated June 19f 1991 RegardingAdditional Language to be Inserted Into Chapter 4 of the Feasi-bility Study and Addendum

EPA has required the insertion of language and alternatives MM-3,1, 9, 10 and 11 to the effect that these alternatives will includeconstruction of a discharge pipe or structure at the Souhegan River orprocess discharge stream which will have limited if no inconsequentialimpact to the immediate environment. The PRP Group has no furthercomment on the EPA's required language, except to note that it wasmandated by the agency.


EPA Letter to Gregory H. Smith, Dated June 19, 1991 RegardingComments on June 5. 1991. Revisions to the Feasibility StudyChapter 3

Comment 1, Page 3-5. EPA has required a change in a discussionof the Baseline Health Risk Assessment for exposure to soils, andrequired the two paragraphs appearing in the revised draft of the FSSection 3 to be replaced by three paragraphs of its own writing.Among the significant changes in EPA's new three paragraphs are dele-tions from the discussion that the Hitchiner/Hendrix area does notpose a health threat unless one assumed the maximum concentration ofPCBs under a future residential use scenario. This deletion isunwarranted. The language in the revised Section 3 should haveremained in the final text. It is in part as follows:

The Baseline Health Risk Assessment considered potentialhealth impact from exposure to chemicals and soil throughingestion and dermal absorption. At the Hitchiner andHendrix areas, of the four exposure scenario considered(present industrial and future residential land uses foraverage and maximum contaminant concentrations), none of theindividual contaminants produce cancer risk greater than 1.0x 10-4 or hazard quotients in excess of 1.0. Under thefuture residential use scenario, the maximum concentrationof PCB (24 ppm) produced a cancer risk of 1 x 10-5. How-ever, this is an area of limited access and the scenario isunlikely. Therefore, no contaminants of interest areidentified for the soil at the Hitchiner/Hendrix area.

Comment 2 and 3. The PRP Group has no comment on the requiredchange.

Comment 4, Page 3-10, fifth paragraph. EPA has required thedeletion of a sentence that the plume in the water table at O.K. Toolis persistent because of DNAPLs. EPA's replacement paragraph removesthe reference to the location of the DNAPL and refers to an unspeci-fied "the locations" without referencing O.K. Tool. This insertion isunwarranted by the site evidence and the reference to O.K. Tool shouldremain in the text.

Comment 5, Page 3-18, third paragraph. The PRP Group has nocomment on the required change.

Comment 6, Page 3-24, third paragraph. The PRP Group notes thatchanges to the paragraph concerning the effects of pumping at theHitchiner plant, will likely be clarified during the RD/RA phase ofthe proceedings, and the Group reserves the right to challenge the EPArequired statements to conform to more accurate information.


Comment 7, Page 3-30. The PRP Group has previously responded toEPA's speculative comment that it assumes DNAPL does not exist at thissite, and incorporates those responses by reference herein.

Comment 8. The PRP Group has no comment on the required changes.

Comment 9. See the Group's response to comment 7 above.

Comment 10. The PRP Group has no additional comment to thisrequired change.

Comment 11, 13. The PRP Group has no comment on the requiredchanges.

Comment 14. Once again EPA has required the insertion of astatement that all alternatives will have a component of periodicevaluation of technologies and state-of-the-art remediation techniquesto address DNAPLs at the site. What this paragraph, among otherthings, fails to mention is that current scientific evidence is unableto locate or treat DNAPLs. The PRP Group has provided further commentpreviously in response to identical language inserted as a result ofEPA's June 18, 1991, Comment Letter, and incorporates those furtherobjections herein. The Group reiterates its objection to writing EPAa blank check to experiment with state-of-the-art remediationtechniques at the government's unchecked discretion.

EPA's June 21, 1991 Letter to Gregory H. Smith Regarding Commentson Amendment to the Feasibility Study

Comments 1 - 5 . The PRP Group notes EPA's comments.

Comment 6. EPA has required the Feasibility Addendum to containthe identical language concerning the periodic review of state-of-the-art techniques to address the DNAPL problem. The PRP Group, again,objects to this required language and incorporates its previouscomments on this topic herein.

Comments 7-13. EPA's comments are noted.

Comments on Chapter 4

Comments 1 and 2. The PRP Group notes EPA's comments.

Comments 3 and 4. The PRP Group has previously responded tothese EPA required changes and incorporates those responses herein.

Comment 5-8. The PRP Group notes EPA's comments.


EPA's June 23, 1991. Letter to Gregory H. Smith. RegardingComments on Feasibility Study Addendum, and Chapter 4

Comments 1 - 3. The PRP Group notes EPA's comments.

Comment 4, Page 4-2. EPA has required a sentence stating thatpretreatment of metals will be addressed in the design stage. Thispoint must be emphasized in the Record of Decision. The PRP Groupbelieves that metals pretreatment is unnecessary to complete theremedy at this site, which will mean a significant cost savingsregardless of the remedy chosen. The PRP Group expects that the RD/RAphase of the process will confirm that metals pretreatment isunnecessary.

Comment 5. No response is required.

Comment 6, Page 4-3, second paragraph. The changes have beenmade as EPA has required.

Comment 7-13. EPA's comments are noted.


Comment 14. To the extent required, the PRP Group has respondedto these changes as EPA has directed.

Very truly yours,

THE SAVAGE WELL PRP GROUP

Hitchiner Manufacturing Company, Inc.By its Attorneys,

McLANE, GRAF, RAULERSON & MIDDLETON,PROFESSIONAL ASSOCIATION

Gregory H. Smith, Esq.Mark C. Rouvalis, Esq.

Conductron Corporation, d/b/a HendrixWire & Cable CompanyBy its Attorneys,SHEEHAN PHINNEY BASS + GREEN,PROFESSIONAL ASSOCIATION

By;Daniel Coolidge, Esq.Thomas S. Burack, Esq.

cc: Mr. Frederick Lofgren, VPMr. John MeffenMr. James ZeppieriJ. Michael Deasy, Esq.Maureen Raiche, Esq.

CILCORP Company

EnvironmentalScience &Engineering, Inc.

file:490-5227.0001ref.:trans_lt.svg

March 20,1991

Environmental Protection AgencyRegion IJ.F. Kennedy Federal BuildingBoston, Massachusetts TT^r '"*"> ~02203-2211 "' :" - '•-

Attn.: Richard Goehlert M A R 2 <

Re: Letter of TransmittalRevised Health Risk Assessment ""Savage Well Site

Dear Mr. Goehlert

The accompanying document is the final revision of the Health Risk Assessment Report forthe Savage Municipal Well NPL Site.

The document incorporates revisions that respond to comments from EPA and the NewHampshire Division of Public Health Services (on behalf of the Department ofEnvironmental Services). Changes have been made at the specific request of EPA, whichwishes to have an assessment that is, in its words, "EPA's record." Many of the requiredchanges to the text of the report were for the PRPs to remove language indicating thatcertain exposure scenarios were analyzed specifically on instructions from EPA. As such, itis not apparent from the document that any disagreement exists between the PRPs andEPA on the potential health risks posed by the site.

The PRPs believe there is legitimate debate on the appropriateness of EPA's approach incertain aspects of this particular assessment, scientifically, or as it relates to policy under theNational Contingency Plan. Specifically, the issue of using analytical data from filteredversus unfiltered groundwater samples in a model for potential exposures due toconsumption of potable water is scientifically unresolved. Also, the analysis of risk fromexposures typically associated with residential settings for industrially-zoned areas near OKTool and the State Lot, and on Hitchiner or Hendrix property near the drainage stream isgreater than the "reasonable maximal" exposure called for in the NCP.

One Overlook Drive Ln i t 16 Amherst, NH 03031 Phone (603) 672-2511 Fax (603) 672-2014

Formerly known as Hunter/bca.

Therefore, the PRPs have submitted a short document (Appendix I to the Report)itemizing areas of disagreement and the effect they have on estimated potential risks. ThisAppendix is not referenced in the report, but we respectfully request that this letter and theAppendix be a part of the administrative record for this case.

Appendix H to the Report provides responses on a comment-by-comment basis to thereviews provided by EPA and New Hampshire Division of Public Health Services, per yourrequest.

Please call, if you have any questions.

Sincerely,

Bradley W. Schwab, Ph.D.Associate Vice President

CC: Greg Smith - McLane, Graf, Raulerson, & MiddletonDaniel Coolidge - Sheehan, Phinney, Bass, & GreenMicheal Deasy - Deasy and DwyerMaureen Raiche - Devine and NyquistPaul Merrier - Hitchiner

Mark Huberger - HMM Associates

E5Ei CH.COKF Comp*n,

APPENDIX I

ALTERNATIVE EXPOSURE SCENARIOS

INTRODUCTION

The exposure assessment in a health risk analysis identifies real and potential exposurepathways, receptors, and concentrations of chemicals at specific exposure points. Exposureis quantified with the aid of "exposure scenarios", which identify human activity patternsthat promote exposure (e.g. how much drinking water is ingested per day). Quantitativeexposure information is integrated with estimates of toxic potency of the constituents ofconcern to evaluate potential health risks. Therefore, the potential" risk estimated for a siteis entirely dependent on the assumptions made in the exposure assessment.

The National Contingency Plan requires that a "reasonable maximum" exposure beconsidered in the baseline risk assessment, and defines that term such that "only potentialexposures that are likely to occur will be included in the assessment of exposures" (emphasisadded). Exposure scenarios set forth by ESE in previous reports fit this definition, andwould lead to different conclusions relative to the potential health risks associated with thissite. These alternatives were addressed in an earlier version of the Report (July 10, 1990),but, at EPA's direction, some have been removed or coupled with more conservativeapproaches that are not warranted by site conditions, in this version (March 20, 1991).Specifically, the new report:

1) Does not address potential health risks associated with consumption of groundwaterusing analytical data from filtered groundwater samples.

2) Presents exposure scenarios for contact with soil or sediment in the Hitchiner/Hendrixarea without delineation of the relative probability of an "industrial" versus"residential" exposure frequency and duration.

3) Presents exposure scenarios for contact with soil in the OK Tool area withoutdelineation of the relative probability of an "industrial" versus "residential" exposurefrequency and duration.

The effects of this approach are given below.

GROUNDWATER CONSUMPTION

Groundwater samples for metals were conducted in two ways during the RemedialInvestigation - filtered and unfiltered. There is some uncertainty associated with the use ofthe different samples in determining potential exposure to metals. If a monitoring well

sample is not filtered, sediments entrained in the groundwater are digested by the acid usedto preserve the sample, and sediment metals are dissolved. This sediment would likely notbe present in a drinking water well.

Groundwater monitoring wells typically produce water that is high in suspended solids,because of well construction, development, and purging limitations. Groundwatermonitoring wells typically generate on the order of tens of gallons of groundwater over thelifetime of the well, while a drinking water well will generate on flie order of gallons perminute to gallons per second. The increased groundwater production of the drinking waterwell over the monitoring well results in flushing and a development action on thesurrounding filter pack or natural aquifer formation that tends to clear the drinking waterwell of sediment. Further, special drinking water well construction details, such as artificialor in-situ developed filter packs, filter suspended sediment and paniculate matter fromgroundwater and therefore simulate a filtered monitoring well sample. The filter packfiltering action is anticipated to become more efficient with well use, as the artificial ordeveloped filter pack stabilizes. For these reasons, the filtered monitoring well data betterrepresents the ambient aquifer groundwater, and the risk assessment should include filteredsamples in the risk assessment.

A risk analysis using data from filtered samples was presented in the July 10, 1990 report,but was removed at EPA's direction. The tables depicting this analysis are reproducedhere. As compared to the risk analysis for this scenario presented in the current report(Table 4-1, also reproduced here), the filtered metal data indicate limited risk from metals(arsenic is the only metal producing cancer risk or hazard quotient in excess of unity). Therisk from VOCs indicated by the filtered samples is high and the data do not argue forreduced treatment of organic compounds. However, the need for treatment to addresspotential risks from metals is not indicated by the filtered samples.

SOIL OR SEDIMENT CONTACT - HITCHINER/HENDRIX AREA

The current report considers the potential risks of contact with sediments or soils in thearea near the Hitchiner/Hendrix drainage stream both for a worker and for children. Thefrequency and duration of exposure, as well as the soil ingestion rate, considered in thelatter case is typical of that which might occur if the property were developed for residentialuse. In the report, the scenarios are characterized as "present" and "future", respectively.However, no worker has a job that would foster the exposure rate in the worker scenario,and there are both zoning restrictions and practical barriers to use of the Hitchiner andHendrix property for residential use (both companies have successful ongoing operationson the property). Therefore, the scenarios should be considered alternative analyses ofpotential future use, rather than present and future. The PRPs believe the continued

industrial use of the area is the far more likely scenario and that assumed residential use issufficiently unlikely that it does not fit the NCP definition of reasonable maximum.

The preamble to the National Contingency Plan final rule, published in February, 1990states that The assumption of residential land use is not a requirement of the program butrather is an assumption that may be made, based on conservative but realistic scenarios, toensure remedies that are ultimately selected for the site will be protective. An assumptionof future residential land use may not be justifiable if the probability that the site willsupport residential use in the future is small." The preamble also states "Where the likelyfuture land use is unclear, risks assuming residential land use can be compared to risksassociated with other land uses, such as industrial, to estimate the consequences if the landis used for something other than the expected future use." This comparison can be made byinspecting Tables 4-4 (sediment contact) and 4-5 of the current Report (also reproducedhere). It can be seen that the worker scenario for contact with sediment estimates risksfrom approximately 1E-6 and 4E-6 (for average and maximum chemical concentrations,respectively), while the residential scenario estimates potential risks of 4E-6 to 1E-5(hazard indicies did not exceed unity in either scenario). Contact with soil for the workerscenario produces risk estimates of approximately 1E-6 and 2E-5 (average and maximumchemical concentrations), while the residential scenario is approximately one order ofmagnitude higher (1E-5 and 1E-4).

It is also worth note that the current report considers exposure in the worker to occur for 40years, rather than the 10 year exposure assumed in the previous Report. Forty years is atypical maximum (not average) value for a career duration, but the exposure consideredhere requires that a worker maintain a single, specific position (caretaker) for the durationof exposure. The maximum time that a worker at the Hitchiner or Hendrix facilities wouldbe employed for so specific a task is unknown. Forty years might be appropriate to anexposure that occurs regardless of the specific task a worker is doing (such as exposure tochemicals in the work environment, where exposure would continue even if the workerchanged jobs but remained in the same general area), but it is unlikely that the specificdudes required to maintain soil contact would last this long. It is important to note that awork position requiring the son of contact identified in the scenario does not exist. Use ofthe the ten-year assumption used in the previous Report would cause risk estimates forworkers to be diminished by a factor of four, and be at the low end of the reference riskrange often used by EPA in determining cleanup requirements. The difference in theestimated risk levels between residential and industrial use of the property would causesubstantially different risk management decisions relative to soil or sediment treatment orremoval. An industrial scenario, with reduced duration, is a reasonable maximal exposure.

SOIL CONTACT - OK TOOL AREA

In the present report, scenarios considering soil contact in children were developed for twocases — one with an exposure frequency of 30 days per year and one for an exposure of 160days/year. The latter is the frequency used by the New Hampshire Division of HealthServices Bureau of Health Risk Assessment in analyzing potential risks for residentialproperty. These scenarios are characterized as "present" and "future" scenarios.Given the current use of the site, regular contact with material in soils cannot be considered"current.11 Further, zoning and flood plain restrictions would likely preclude use of thisproperty for residences, and a portion of the property is intended as the location of a newbridge crossing the Souhegan River. Therefore, the residential scenario considered byEPA in the current report goes beyond the definition of reasonable maximal under theNCP.

Inspection of Table 4-6 (reproduced here) indicates the estimated risks for the presentscenario are approximately 8E-6 and 3E-5 (average and maximum concentrations), withhazard quotients of 0.15 and 2.9 for chromium, if it is in the VI oxidation state (the HI forchromium III would be less than one). For the residential scenario, the estimates areapproximately 4E-5 and 2E-4, with hazard indicies of 1.2 and 21.

The difference in the estimated risk levels between for different uses of theproperty would result in substantially different risk management decisions relative to soiltreatment or removal. Given the projected use of the property, occasional exposure tochemicals in surface soil is a reasonable maximum exposure.

JMV SSVH A3NNIHJ NVH33HS 710 Si

SHBEHANPHINNEY

BASS +GREEN

PROFESSIONAL

ASSOCIATION

SKBGApril 27,1991

ATTORNEYS AT LAW

1000 ELM STRBSTP.O. Box 3701MANCHESTER

NEW HAMPSHIRE03105-3701

FAX 603-627-8121

603-668-0300

1 HARBOUR PLACESUITE 325

PORTSMOUTHNEW HAMPSHIRE

03801-3856FAX 603 33-3126

603-433-2111

VIA FACSIMILE

Mr. Richard GoehlertU.S. Environmental Protection AgencyRegion IJFK Federal BuildingBoston, MA 02203-2211

Re: Savage Well Site, RI/FS Comments

Dear Dick:

At our meeting yesterday, I raised strong objection to certain of thechanges you have requested in the RI, some of which carry forward to the FS.In most cases, I have been content to limit my objections to a side letter to beincluded in the record of decision, However, certain of the specific languagechanges you directed to be made as "non-negotiable" are unsupported by thedata, and so serious as to warrant their not being included as requested.

In a number of places, including Paragraph 28 of your April 21 letterconcerning Chapter 1 of the FS, and also on rage 7-8 of the RI comments, yourequested language which reads

"Furthermore, while the results of groundwatersampling completed during the RI does not indicatesources of TCA contamination in the vicinity of theHendrix and NESFAB facilities, historical data of usageof the chemical as well as other chemicals and historicalsampling data indicate sources at the facilities."

There is no data whatsoever which would indicate a source ofTCA at Hendrix. The most that can be said is that TCA is foundin the groundwater under Hendrix at levels consistent with ithaving migrated from an upgradient source. There is no historicalsampling data indicating TCA sources at Hendrix whatsoever,although there is information that Hendrix, like most othercompanies in the area, has at one time used TCA.

I would offer the following language as a substitute:

"While the results of groundwater sampling completedduring the RI does not indicate a source of TCA

wv : • • *e-;:-s: ssva A3NNiHd NVHHHHS

Mr. Richard GoehlertApril 27,1991Page 2

contamination either at the Hendrix or NESFABfacilities, both companies have used TCA in the pastIn the case of NESFAB, historical sampling indicates asource of TCA as well as other chemicals. It is possiblethat releases of TCA may have occurred at either oneor both of these facilities in the past, but because of thehighly permeable nature of the aquifer underlying thesite area and the large volume and long-term pumping(which is equivalent to induce flushing) of groundwater,it may not be possible at this time to delineate specificsources of these chemicals at these faculties."

I trust that meets with the tenor of what YOU intended to say,while resolving my objection to the unfounded conclusion thatthere is a source 01 TCA contamination at Hendrix,

Throughout your requested changes there is continuingreference to the "Hitchiner/Hendrix facility". I do not want anyimplication that Hitchiner and Hendrix constitute a single facility.Such is not the case: they are separate, independent companies,and should not be tarred with the same brush. I would requestthat references to the Hitchiner/Hendrix facility be changed toread, "Hitchiner and Hendrix facilities."

You requested the inclusion of a statement on Page 4-33 ofthe RI which reads:

"The sampling results indicate a primary source for theTCA contamination at the location of the Hitchinerfacility and possibly at the Hendrix facility."

I know of no data whatsoever which indicates a possible source ofTCA contamination at the Hendrix facility. The concentration ofTCA emanating from the Hitchiner facility decreasesmonotonically from the Hitchiner to the Hendrix facility. There isno indication of an additional source, either by an increase inconcentration or a change in the second derivative ofconcentration over distance. In the absence of such evidence, Iwould request that the "and possibly at the Hendrix facility" bedeleted. If for any reason I have missed something in the RI whichwould indicate otherwise, I would be most happy to talk with youon this point

As we discussed at our meeting yesterday, it was not theargument of the PRPs that DNAPL sources exist wherever thereare high concentrations of VOCs. It appears that direct evidenceof free phase DNAPL sources may have been located at the O.K.

5SVS AZNNIHd NVH33HS

Mr. Richard GoehlertApril 27,1991Page3

Tool site where one or more samples was at or above the solubilitylimits for a particular chemical. It was raised as a possibility thatthe TCA source emanating from the Hitchiner facility may alsohave free phase DNAPL associated with it, although no directevidence has been found.

No evidence of any kind has ever been found to suggest orsupport the argument that there is a source of contamination ofeither PCE or TCA emanating from the Hendrix facility. All thatcan be said is that there is contaminated groundwater underneaththe Hendrix facility, the levels of which are consistent withcontamination flowing downgradient from an upstream source. Iask that the reference to the Hendrix facility be deleted from thesuggested change on 4-37. There is some question about thepossibility of a DNAPL source in the vicinity of MW-20.

In the interest of time, unless I hear from you on Monday,April 29 to the contrary, I will instruct HMM to make thesechant ~ ~ ~ '*- -' '"- - . 1 - i - . . . . - • , , - j •..accorc

U *7 kU IUE< WUUllOiy, A Will 1U3UUI.I. AAiTAJTl LU UULfeb UlbSC*

iges so that the RI revised pages may be submitted inrdance with your letter of April 26,1991.

If you would like to discuss this matter over the weekend, myhome number is 603-456-2274. I should be home Sundayafternoon, and Saturday late afternoon.

Very truly yours,

"0>*-XJ2 ^- <?Daniei S. Coolidge

DSC/mm

cc: Gregory R Smith, Esq.JohnMeffenEugene Holloway, Esq.

SSVS A S N N I H d NVH33HS H O H £

KENNETH F, 0RAFJOHN H. MCLANC, JR.»SM»TA, RAULIRIONJACK 9. MIDDkETDNJOHM A. 3RAFCHAftLIS A. OE«RANDP«JAMK* R. MVIRHEAOPETER *. ROTCHARTHUR 9, OREENCROIERT A. WELLSR. OAVIO 0«PUY•MUCK W. FCLMLYJAMES C. HOODJ. CHRISTOPHER MARSHALLROBERT C. JAURONTHOMA1 J. DONOVANLINDA CHAN CALL CONN ILLWILBUR A. ALAHN. inCAROL ANNWILLIAM V, A.

, SMITHA. SAMUELS

KEVIN M. FITMERALO• RANCH «. BAMBCR*DAVID C. BARRAOALC•TCVEN V, CAM CRI MOJOSCPH A. FOITEMRUTH ANtCLU

or COUMDILNORMAN t. D'AMOURB

McLANE, GRAF, RAULERSON & MIDDLETONPROFt«81<SNAU ASSOCIATION

FORTY STARK STREET

P. O. BOX 326MANCHESTER, N.H. O3lOS-O32e

TELEPHONE («03) 63S

PAX («Q3) «28-I«SO

FORTY CONHBeSS STREETP. O. BOX *3I«

PORTSMOUTH, N.H. O3«OS-*3I*TELEPHONE (•«!>

SlCENTtNNIAL JQUARIFIFTEEN NORTH MAIN STREET

eoNcono. N.H. oaaoiTELEPHONE («OJ> ISO-94OO

PAX t«oj>

June 4, 1991

JUDITH A, FAIRCLOOOHCQNNIC OOVttS LAN*RALPH F. MOUMUMADIA HOLLAND LAWKATHLEEM M. ROSINSONALICE K. F*UEMICHAEL L. HENRYPETER D. ANOIRBQNTHOMAS w. HILORSTH'PAMELA J. NEWKIRKMICHAEL 8. TUL«BAVID WQLOWITXSTSPHCN S. WIU.IAMSKEVIN M. LEACHJOSEPH 0. LEVENONCM1CHACLJ. 4U1NMCHMmtlMK *. ANDtRSONDAWN I. IROWNaUZANNr H. 90RMAHMARK C. HOUVAUSAMNE M. COWARDS

STEVEN M. SURKCKILEEN L. KOCHLEHCHARLES W. 3ERWAN, JR.4CMMA M. OREMCRJ, KIRK TROMllLCr*CYNTHIA L. (VMEILk

'ALSO ABHITTCD IN MAINC

Mr, Richard Goehlert " "U.S. EPAJFK Federal BuildingHSN-CANSBoston, MA 02203-2211

Res Savage Well Site - Hendrix Letter of April 27, 1991

Dear Mr, Goehlerti

While I recognize this matter is in a sense behind us now, Iam reluctant to leave Hendrix's letter dated April 12, 1991 toyou unanswered. I have attached a copy of that letter for yourconvenience. Hitchiner does not object to the proposed languagechanges concerning potential TCA "sources" at Hendrix that Mr.Coolidge suggested in his letter. Hitchiner wishes to point outfor the administrative record/ however, that it disagrees withthe statements and implications in Mr. Coolidge's letter that theprimary explanation for the TCA contamination at Hendrix resultsonly from a TCA source at Hitchiner. The levels of TCA detectedat Hitchiner do not demonstrate, according to Dr. Cherry'sanalysis, the existence of a DNAPL TCA source. In addition,Hendrix has used TCA and discharged it through a NPDES permit,for a number of years. It is reasonable to conclude that the TCApresent in the groundwater at Hendrix premises derives fromreleases or discharges on its premises.

We hope this clarifies Hitchiner's position with respect toMr. Coolidge's letter. Please let me know if you have anyquestions.

GHSsMCR/cmgcc: Daniel Coolidge, Esq.

'Grego Smith

2.1 INTRODUCTION

The purpose of Section 2.0 of the Savage Well Site FS is to identify, screen, and select the

most appropriate remedial technologies which can be subsequently combined into remedial

action alternatives. The selection process is performed pursuant to current EPA RI/FS guidance,

(Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA -

Interim Final OSWER Directive 9355.3-01, October, 1988), and the National Contingency Plan

as revised and reported in the March 8, 1990 Federal Register.

The development of remedial alternatives consists of six general steps which are discussed

below:

Develop remedial action objectives specifying the contaminants and media of

interest, exposure pathway s_ and remediation goals that permit a range of treatment

and containment alternatives to be developed. The objectives developed are based

on contaminant-specific ARARs, when available, and risk related factors.

• Develop general response actions that address the objectives for each medium of

interest.

• Identify volumes or areas of media to which general response actions might be

applied, taking into account the requirements for protectiveness as identified in the

remedial action objectives.

Identify and screen the technology categories applicable to each general response

action to eliminate those that cannot be implemented technically at the Savage

Well site or would not be effective in treating site contaminants.

• Identify and evaluate technology options to select a representative process for each

technology category retained for consideration. Although specific processes are

selected for alternative development and evaluation, these processes are intended

to represent the broader range of process options within a general technology type.

• Assemble the selected representative technologies into alternatives representing a

range of treatment and containment combinations, as appropriate.

2176-160/HAZ-4714 2-1

The selection process emphasizes sorting of technologies to achieve a reliable remedy

which acknowledges the practical limitations of the use of treatment. Furthermore, this process

is undertaken with the flexibility necessary and appropriate to ensure that remedial actions

selected are reliable solutions for the identified site problems.

The following sections of the Feasibility Study follow a site-specific analysis and one that

is biased toward action. This approach is focused on the alternatives that are available to

effectively address DNAPLs and the alternatives that are practical given the extent and nature of

the contamination and the unprotected, unconfined nature of the aquifer. In addition, many

identifiable alternatives are inappropriate because the risk assessment has demonstrated that

groundwater is the only medium of concern at the Site. Therefore, the alternatives that are

developed in ensuing sections of the Feasibility Study are those that are appropriate for the

specific conditions of the Site.

The National Contingency Plan provides several other criteria and conditions that

emphasize that a site-specific selection process is warranted. The groundwater at the Site is not

currently used as a drinking water source. In addition, adequate drinking water supplies are

currently available to replace the supply formerly provided by Savage Well. New Hampshire

regulations may proscribe future use of the aquifer as a municipal supply because the current and

foreseeable future use of the land area that is contributory to the aquifer includes incompatible

uses such as industrial, commercial and agricultural. Therefore, remediation of the active

aquifer to the 10" * to 10"" human health criteria levels may not be appropriate.

MCLs may be achievable in those portions of the aquifer where there are dilute

contaminants but on the basis of current scientific evidence they may not be achievable for the

concentrated plume where contaminants likely exist as separate phase, or dense non-aqueous

phase liquids (DNAPLs).

Subsequent evaluations of groundwater treatment options will examine the benefits and

costs of various alternatives including recovery and treatment of concentrated plume and

recovery and treatment of the extended plume along with natural attenuation. The time frames

will be assessed in the context of what the NCP considers to be rapid restoration, one to five+

years, and relatively extended restoration periods, several decades. For example, replacement of

the water supplies, which were drawn from the Site aquifer, has been for the most part

implemented.

The benefits of natural attenuation will be examined in conjunction with groundwater

recovery and treatment and protection of environmental receptors. Natural advection,

biodegradation, dispersion, dilution and absorption may effectively reduce the level of

contaminants in the portions of the aquifer outside the source containment areas to

2176-160/HAZ-4714 2-2

concentrations protective of human health and the environment in a time frame that is

sufficiently rapid. Institutional controls may be necessary to ensure that the groundwater is not

used for potable purposes during the time period in which the CERCLA regulated contaminants

are naturally attenuated.

Clearly in the case of the concentrated plume where contaminants may exist as separate

phase (DNAPL), restoration of the groundwater may be impractical. The Feasibility Study will

consider options for the extraction and treatment of groundwater from the concentrated plume to

prevent migration to downgradient portions of the aquifer.

Based on the existing information regarding the nature and extent of contamination, and

the risks posed to public health and the environment, two general response categories have been

developed for the Savage Well site: 1) Source Control; and 2) Management of Migration.

These categories are identified and explained in Section 2.2, Remedial Action Objectives.

2,2 ? RMHPTAL ACTION OBJECTIVES

This Feasibility Study develops and evaluates remedial alternatives for Source Control

and Management of Migration measures. Source Control alternatives focus on mitigating

residual contaminants in soils and sediments to the extent that such contamination poses

unacceptable risks to human health or the environment. Management of Migration alternatives

are developed to address contamination in two types of areas, specifically:

• areas where contaminants exist as a separate phase, free product, or above their

solubility units (concentrated plume); and

• areas where contaminants exist primarily as a dissolved phase (extended plume).

The concentrated plume areas are likely to result in continued long-term release and

contamination of downgradient groundwater. Based on recent research and experience at other

sites, the concentration of VOCs detected downgradient of O.K. Tool indicate that it is likely

that VOCs exist in the aquifer beneath O.K. Tool as separate phase, dense non-aqueous phase

liquid (DNAPL). Remedial alternatives should place strong emphasis on controlling

contaminant migration from the concentrated plume areas. The existence of DNAPL at the

Savage Well Site has been inferred from the following:

2176-160/HAZ-4714 2-3

• historical materials management practices;

concentrations of dissolved chlorinated hydrocarbons in groundwater immediately

downgradient from O.K. Tool and in groundwater sampled during source-removal

excavations at O.K. Tool;

• calculations based upon concentrations of chlorinated hydrocarbons in soils

removed during excavations at O.K. Tool; and

• contaminant behavior and site geology and hydrogeology, which provide for

unrestricted downward vertical migration of denser-than-water contaminants

through highly permeable overburden.

Because of the typical occurrence of DNAPLs in discontinuous lenses and pools, and because of

the low miscibility of PCE and other chlorinated solvents, the DNAPLs present a persistent

long-tem source of solvents. While it may not be technically feasible to isolate and recover the

DNAPL accumulations, removing or containing volumes or masses of contaminants in the

concentrated plume will reduce the overall extent of contamination and the time frame required

to return the balance of the aquifer to its beneficial use.

The Management of Migration alternatives focus on remediating the concentrated plume

and contaminated off-site groundwater east of the trailer park and preventing further migration

of contaminated groundwater to downgradient receptors including fish hatcheries, the Souhegan

River and other potential water users (see Figure 2-1). There currently exists a discharge of

contaminated groundwater from the aquifer to the Souhegan River. There is also evidence that

there is limited migration of contaminated groundwater to the north of the Souhegan River

including migration to production wells used by a private fish hatchery (Souhegan Valley

Aquaculture). Remedial alternatives should be developed and evaluated as to the feasibility of

mitigating -any environmental or health impact posed by this migration of contaminated

groundwater.

Due to the potential future demands for groundwater and surface water resources in the

Milford area, remedial action objectives should include consideration of returning the aquifer to

a level of water quality which is consistent with its most beneficial use in the future. Although

the majority of the land area overlying the contaminated portion of the aquifer is currently and

for the foreseeable future zoned for industrial use, only a portion of it has been developed as

such. The zoning as of March, 1990 is illustrated on Figure 2-1. Depending upon subsequent

growth and municipal needs, portions of the industrially zoned portion of the aquifer may at

some point be reclassified as commercial.

2176-160/HAZ-4714 2-4

Some portion of the contaminated aquifer may be excluded from full remediation due to

technical feasibility and cost considerations. However, remedial alternatives should be

developed and evaluated which would over some time frame restore a portion of the aquifer to

some practical level of beneficial usefulness.

2.2.1 (^nntaTningntff of TnteiCSt

Contaminants have been detected at the Savage Well Site in groundwater, surface water,

sediments, soil, and air. The overall objectives of remediating the site are to reduce the risks to

public health and welfare and to the environment. Specific remedial response objectives for the

Savage Well Site are based on the exposure levels and associated risks posed by the nature and

extent of contaminants. These exposure levels, risks and supporting documentation are

identified in the Remedial Investigation (RI), in the baseline risk assessment, and in the

Applicable or Relevant and Appropriate Requirements (ARARs) for remedial alternatives.

Groundwater

The primary remedial action objectives for the site focus on groundwater. The specific

objectives are to return the groundwater to some level of beneficial uses in a reasonable time

frame consistent with the current land-use of the site; the nature and distribution of

contaminants; the physical/technological constraints to removing contaminants; and the sources

of the on-site contamination.

Contaminants of interest in developing remedial action objectives for groundwater were

determined based on the frequency of occurrence as documented in the RI, the results of the

baseline risk assessment, and the chemical specific ARARs as identified in Section 2.2.6. The

remedial response objective for groundwater to protect human health is to prevent future

ingestion or household use of groundwater having the compounds of interest at levels which

exceed Maximum Contaminant Levels (MCLs); exceed a total excess lifetime cancer risk of

10"4 to 10"" (based on the risk assessed); and/or exceed reference doses. Exposure scenarios for

potential future use of groundwater as drinking water or for household use produced cancer risks

or hazard indices above typically acceptable remediation target ranges for the following

compounds:

tetrachloroethylene (PCE)

trichloroethylene (TCE)

2176-160/HAZ-4714 2-6

have been detected in several samples at O.K. Tool. However, levels of As and Pb have not

been detected in groundwater samples from monitoring wells in this area at levels above the

MCLs. There is a large amount of uncertainty involved in the use of the Summers model for

metals due to the wide range of reported Koc and Kd values for metals, and, based on the

observed site conditions, it appears that the amount of leaching of metals may be less than that

predicted by the model.

Surface Water

The risk assessment for surface water exposure scenarios produced risk levels and hazard

indices below the target ranges. Because there is a low potential for use of surface waters as a

drinking water supply, MCLs are not applicable in developing remedial action objectives for

human health protection. There are, however, several contaminants which were detected in

surface waters at levels which exceed the Federal and New Hampshire Ambient Water Quality

Criteria for protection of aquatic life, which are applicable ARARs. These include toluene

(SW-19), acrolein (SW-19), copper (SW-4 through SW-9), lead (SW-5), nickel and chromium

(SW-5).

The locations of the elevated levels of toluene, acrolein, lead, and chromium are all in the

process water discharge stream, at or immediately adjacent to the permitted industrial outfall

from the Hitchiner facility, and are within the limits established by the NPDES permit. Copper

levels were found to exceed AWQC levels at five points (SW-5 through SW-9) along the length

of the discharge stream, but were below the permitted discharge levels. Copper levels drop

significantly along the length of the discharge stream and are below detection limits (and below

ARAR levels) in the Souhegan River, indicating that the river is not being impacted by copper in

the discharge stream. Sampling of sediments and surface water in the Souhegan River was

performed during a period of low flow (September 5-6, 1989) such that these results are

considered as representative of levels that would occur in the stream under the typical range of

flow conditions (see Section 3.2 of the RI).

VOCs occur in the discharge stream in part as the result of process water pumping wells

intersecting the outer fringes of the plume on the south side of Route 101. The concentrations in

the discharge stream are significantly lower than those in the aquifer to which it discharges.

Discharge of low levels of contamination to the area of the aquifer that is already affected by

high levels of contaminants would not increase the overall contaminant level or the time frame

required to reach remedial goals. The results of the baseline risk assessment have not shown the

discharge stream's contribution to the underlying aquifer to pose an unacceptable risk.

Additionally, Hendrix has terminated their discharge, and Hitchiner has made process

2176-160/HAZ-4714 2-12

modifications to reduce their discharge since the time of the RI sampling. Therefore,

remediation of discharge stream waters is not appropriate in protecting ground-water quality or in

achieving groundwater remediation objectives.

For the reasons discussed above, no compounds of concern have been identified and no

remedial action objectives need to be developed for surface water for protection of either human

health or the environment.

Sediments.

The baseline risk assessment for exposures via ingestion or dermal absorption of

contaminants in sediments produced risk estimates within the target range for performance goals

and hazard indices below unity, i.e., references doses were not exceeded. There are no Federal

or New Hampshire ARARs that specify sediment concentration limits for protection of human

health. Therefore, no compounds of interest are identified and no remedial action objectives

need to be developed for the protection of human health.

Remedial action objectives for the protection of the environment should be to prevent or

mitigate releases from sediments which would result in surface water contaminant levels in

excess of AWQC. The only contaminants for which concentrations detected in sediments are

significantly higher than AWQC levels in surface water are metals in sediments immediately

adjacent to the NPDES -permitted industrial outfalls at the Hitchiner Facility (SW-4, SW-5, and

SW-6), at the extreme upstream end of the discharge stream. As discussed in the surface water

section, there is no indication of elevated levels of any metals in the waters of the discharge

stream except copper and there is no indication of an impact to the Souhegan River from metals

in the discharge stream. The chemistry of the soils, metal and water suggest that these metals

are relatively immobile in their present location. For these reasons, no remedial action

objectives need to be developed for sediments for protection of the environment.

Contaminants detected in air consist of acetone, methylene chloride, tetrachloroethylene,

and 1,1,1 trichloroethane. All detected concentrations were below the proposed New Hampshire

Ambient Ak Level (AAL) guidelines and the Risk Assessment did not identify any unacceptable

risks from inhalation exposures. Therefore, no remedial action objectives are developed for air.

2176-160/HAZ-4714 2-13

Mr. Richard A. GoehlertDecember 11,1990

Page 4

ENVIRONMENTALPROJECT CONTROL

presence of DNAPL. If the DNAPL were not present, the concentration ofcompounds in the extracted ground water would be expected to diminishover time. The data generated from chemical quality monitoring of purgewells obviously arrives very late in the remedial process. Earlyunderstanding of the presence of DNAPL is critical to avoid incorrectlyplacing extraction wells, as well as to avoid unrealistic expectations for the sitecleanup program.

SITE CONDITIONS

The reports "Proposed Clean-Up of Soils in the Vicinity of the IndoorDegreasing Tank at the O.K. Tool Company, Inc.," July 1984, "Soil Removalfrom beneath Indoor Degreasing Tank OK Tool Company, Inc.," January 3,1985, and "Phase II Site Investigation Summary Report OK Tool Company,Inc.," November 15, 1984 prepared by Normandeau Associates, Inc.(Normandeau) describe dear evidence of DNAPL having been used andreleased at the OK Tool property. Normandeau found significantconcentrations of tetrachloroethene in shallow soil samples adjacent to afloor drain in the facility. At a depth of 2 feet, the total soil tetrachloroetheneconcentration was 300,000 micrograms per kilogram (p.g/kg). At two othershallow holes near the floor drain, soil concentrations were found at levelsup to 28,000 jig/kg. Using the methods in the reference in footnote 2, thecalculated pore-water concentrations are far in excess of the laboratorysolubility of tetrachloroethene, which is 150,000 p.g/1. These results indicatethat tetrachloroethene in a pure phase entered the subsurface in this area.Given that tetrachloroethene has entered the subsurface, it is then reasonableto expect, unless an exceptionally small volume was spilled, that it penetrateddeeply into the system. Such evidence from shallow soils of DNAPL entry tothe'subsurface is strong indirect evidence that DNAPL is present at depth.

Normandeau also located three other areas where tetrachloroetheneconcentrations in shallow soils clearly indicate that residual DNAPL waspresent in the samples. One of these soil samples had a measuredtetrachloroethene concentration of 1,100,000 fig/kg, as well as 1,1,1-trichloroethane at 1,800 (ig/kg, and trichloroethene at 400 Lig/kg, andconcentrations were reported to increase with depth.


PageS


In general, DNAPL sites have high concentrations at depth in the groundwater flow system. The ground water data from this site are entirelyconsistent with this generalization. Elevated concentrations can develop indeep wells and piezometers under two scenarios: 1.) DNAPL residing at depthin the system; and 2.) shallow, contaminated ground water migrating withvertically downward hydraulic gradients. Direct evidence of DNAPL has notbeen obtained during drilling at the Savage site. A large number ofmonitoring wells at the OK Tool property were installed in the early 1980s,preceding knowledge of DNAPL behavior. As a result, the older wells areinappropriately designed for collection of data of the type needed to confirmthe presence of DNAPL at the bottom of the unconsolidated aquifer, DNAPLpresence in bedrock or hydraulic gradient conditions.

The magnitude and direction of the vertical component of the hydraulicgradient, which, if downward, could transport dissolved concentrations to thebedrock wells, are practically impossible to determine accurately because ofthe length of some of the monitoring well screens. There are limited bedrockmonitoring-wells that are paired with wells in the unconsolidated deposits atOK Tool, and there are no multiple-well clusters located in theunconsolidated deposits. Those monitoring wells that are paired have verylong well-screens in the unconsolidated deposits. These long screens willindicate the average hydraulic head above bedrock and are not useful indetermining the direction nor the magnitude of the vertical component ofthe hydraulic gradient.

The dearest evidence of DNAPL from the ground water concentration data isfound at MI-24, which has a screened interval of approximately 80 feetthrough the unconsolidated deposits. This well has consistently measuredtetrachloroethene in the range 14,000 to 19,000 jig/1 since January, 1989.These concentrations are consistently greater than ten-percent of thesolubility, clearly indicating the presence of DNAPL. Furthermore, theseconcentrations are detected in a monitoring well that is screened over a verylong interval, the tremendous span of which is likely contributing to dilutionof the actual tetrachloroethene concentrations.

The monitoring cluster MI-25/MI-26 is a bedrock/unconsolidated deposit pairof wells that have been found to have concentrations of tetrachloroethene.The unconsolidated deposit well (MI-26) has a measured tetrachloroethene of1,800 (15/1. While this concentration alone does not necessarily indicate


Page 6


nearby DNAPL, it is important to note that the well screen is approximately80 feet in length. This concentration could be generated by one of two means:1.) a much higher concentration entering the well over some limited zoneand being diluted; or, 2.) a consistent concentration could be present along thelength of the well screen. In either case, this concentration is sufficientlyhigh to suggest that DNAPL, whether as a distributed residual or as anaccumulation, is probably present in the unconsolidated aquifer.

In addition to this tetrachloroethene concentration in the unconsolidateddeposits, the bedrock well (MI-25) has been found to have tetrachloroetheneat a concentration of 200 jo.g/1. Approximately 400 feet to the north of MI-25,well MI-22, which is screened only in the bedrock, has had measuredtetrachloroethene concentrations of 2,700 and 2,800 |ig/l, or nearly 2-percentof the solubility of pure tetrachloroethene, and strongly suggestive of a nearbyDNAPL accumulation or residual.

To help illustrate some of the issues regarding the indirect detection andconfirmation of DNAPL, enclosed please find two recent papers on the subjectthat have been previously referenced in footnotes 1 and 2.

It is essential, in our opinion, to focus the FS upon DNAPL. The presence ofDNAPL should be used to direct the evaluation of remedial alternatives. It isdear that the issue at the site is DNAPL. In these circumstances, neither thePRP, nor any of their consultants, could take the position that this site can beeasily and quickly cleaned up by large-scale pumping. Removal and cleanupof the DNAPL cannot be accomplished using available technology, and,moreover, should not be attempted because of the likelihood of exacerbatingthe situation. The best current technology can accomplish is to contain theDNAPL and prevent their further migration. In the presence of DNAPL, the"Site" cannot be cleaned up and it is inaccurate and misleading to suggestotherwise. The DNAPL can be handled only by containment and the massremoval attendant thereto. Once effective containment has beenimplemented, remediation of the larger aquifer volume may be achievable.


Page?


Should you have any questions regarding the foregoing, please do nothesitate to contact either of the undersigned.

Sincerely,

Cl_-J ~ "• \

Timovthy'Senior Hydrogeologist

John A. Cherry, Ph.D/Chairman

TMC/JACJisEnclosures

cc R. WiUey (EPA)D. Coughlin (EPA)Gregory H. Smith (McLane si al.)Dardel S. Coolidge (Sheehan et d.)Maureen E. Raiche (Devine & Nyquist)J. Michael Deasy (Deasy & Dwyer)Mark Heuberger (HMM)

Two Grafton Co ionPost Office Box 536GraftonMassachusetts01519

FAX 508/839-7852TEL 508/839-0033


VIA FACSIMILE and U.S. MAIL

January 7,1991

Mr. Richard A. Goehlert 5Remedial Project ManagerNH Superfund SectionUS EPA, Region I r£ \j r N 'c -"J.F. Kennedy Federal Building u

Boston, Massachusetts 02203-2211

RJE: Savage Municipal Water Supply Superfund Site "* ^^^ ~J

EPC Reference No: 9002/020

Dear Mr. Goehlert:

This letter is intended to clarify and augment my December 11,1990 letter discussion of soil andground-water contamination evidence that supports the presence of DNAPL at the OK Toolsite. Since my previous letter, I have acquired technical reports prepared by NormandeauEngineers in 1983 and 1984 when the soil contamination was first being investigated. Ofparticular interest are the soil tetrachloroethene concentrations and the theoreticalcalculation of associated pore-water concentrations. In addition to the soil concentrationsmeasured by Nonnandeau, ground-water samples also were collected from shallow excavationsduring source removal.

As I discussed, the total tetrachloroethene concentrations measured in soil samples can be usedto demonstrate that DNAPL entered the subsurface. The calculations that lead from total soilconcentrations to pore-water concentrations were presented in Feenstra et. al. (in press), a copyof which I forwarded with the December 11* letter. The attached Table 1 lists theassumptions and values used to make these calculations. A number of soil samples collected byNonnandeau are listed in the lower portion of Table 1. Note that only three of these samplesproduce calculated pore-water concentrations that exceed the solubility of puretetrachloroethene; however, five other samples lead to calculated pore-water concentrationsthat are very close to, or exceed, the 10-percent of solubility guideline. Although there arethree samples with pore-water concentrations that grossly exceed maximum solubility limits,though, only one is needed to demonstrate that DNAPL has been spilled.

In addition to the evidence from converting total-soil-concentration data to pore-waterconcentrations, measurements of ground-water concentrations in the vicinity of the same sourceareas are strongly suggestive of residual DNAPL in the saturated zone. Table 2 presents some ofthe tetrachloroethene concentrations in ground-water samples collected by Normandeau. Anumber of the concentrations from monitoring wells exceed the ten-percent guideline (if the

Mr. Richard A. GoehlertJanuary 7,1991

Page 2


ground water concentration is ten-percent of the effective solubility or greater, DNAPL is likelyto be present in the aquifer). In addition, the two ground-water samples collected from thesource-removal excavations far exceed the ten-percent guideline and indicate that residualDNAPL was present.

In my previous letter I discussed the fact that it may be inappropriate to compare calculatedpore-water concentrations with the solubility of the pure compound. The solubility of thecompound will be reduced by the presence of other compounds in the DNAPL, as well ascompounds in the ground water. Unfortunately, it is not possible to calculate the reduced,effective solubility at the Savage site because a sample of the DNAPL has not been collected.

Should you have any questions regarding the foregoing, please do not hesitate to contact me.

Sincerely,

Timothy M. CosgraveSenior Hydrogeologist

TMGhsEnclosurecc R. Willey (EPA)

D. Coughlin (EPA)Gregory H. Smith (McLane et a/.)Daniel S. Coolidge (Sheehan et al.)Maureen E. Raiche (Devine & Nyquist)J. Michael Deasy (Deasy & Dwyer)Mark Heuberger (HMM)

Mr. Richard A. GoehlertJanuary 7,1991

Page3


References

1. Normandeau Associates, Inc. November 15, 1984. Phase n Site Investigation SummaryReport. OK Tool Company, Inc., Milforci, NH.

2. Normandeau Associates, Inc. July, 1984. Proposed Clean-up of Soils in the Vicinity ofthe Indoor Degreasing Tank at the OK Tool Company, Inc.

3. Normandeau Associates, Inc. May, 1984. Report of Water Quality Monitoring, OK ToolCompany Site, Milford, NH. February 10, 1984 Sampling.

4. Normandeau Associates, Inc. August, 1984. Report of Water Quality Monitoring, OKTool Company Site, Milford, NH. May 11,1984 Sampling.

5. Normandeau Associates, Inc. September, 1984. Report of Water Quality Monitoring,OK Tool Company Site, Milford, NH. August 22,1984 Sampling.

6. Normandeau Associates, Inc. January 3, 1985. Soil Removal from Beneath IndoorDegreasing Tank, OK Tool Company, Inc., Milford, NH.

Table 1

Compound: Tetrachioroethefie"Water Solubility (ppb)

1%5%

10%

150,0001,5007,500

15,000

Equation:Cw=(Ct*Rb)/(Kd*Rb + Pw + Hc'Pa)

where: Cw = pore-water concentrationCt = total concentration

Pw =water-filled porosityPa =air-fiiled porosityRb =dry bulk densityfoe =organic carbon fraction (M)Kd =partition coefficient (foc'Koc)He =Henry's Law constant (R)

Koc =octanol/water partition coeff. (R)

Value

0.050.201.90

0.00230.850.294370

(M) = measured value; (R) = reference value; all others are assumedAfter Feenstra etal. In press.

Savage Site Data

SampleName

Subfloor A1Subfloor A2Subfloor B1Area 1Area 2, F-14-7, 1Area 2, F-14-7, 4Area 2, F-14-7, 8Pertrtank, 1 ft

Analytical results

Measured TotalConcentration

(uq/kq)12,000

300,00028,000

1,100,000ft 220,000ft 18,000ft 12,000

19,000

from references 1 and 2

CalculatedPore-Water

Concentration(uq/l)

13,212330,30130,828

1,211,103242,22119,81813,21220,919

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December 11,1990

Mr. Richard A. GoehlertRemedial Project ManagerNH Superfund SectionUS EPA, Region IJ.F. Kennedy Federal BuildingBoston, Massachusetts 02203-2211

RE: Savage Municipal Water Supply Superfund SiteEPC Reference No: 9002/010

Dear Mr. Goehlert:

We have reviewed your November 21, 1990 comments regarding the draft FSprepared by HMM Associates for the Savage site. The major points of issue inyour comments were the focusing of the FS upon the presence of DNAPL andthe lack of any discussion regarding removal of the free product or separatephase (DNAPL). We would like to provide additional comments that addressthese issues, as they are of great significance for the site.

As you are aware, the specific gravity of DNAPL causes it to migrate quicklydownward when spilled onto the ground above unconfined sand and gravelaquifers. As the DNAPL moves downward, some adheres to the soil as blobsor ganglia, causing a residual that probably occupies ten-percent or less of thepore space1. If sufficient product is spilled, accumulations may occur in layersor small "pools" upon impeding layers. Recent research on the movement ofDNAPL immediately after a spill has revealed some interesting tendencies of

1 Feenstra, S. 1990. Evaluation of multi-component DNAPL sources by monitoring of dissolved-phaseconcentrations Presented at the Conference on Subsurface Contamination by Immiscible Fluids,International Association of Hydrogeolegists, Calgary, Alberta, Canada, April, 1990.


Page 2


such materials. The research indicates that small heterogeneities inpermeability or the capillary properties of a porous medium can havesignificant implications for the path and manner of movement. Forexample, if the spill should occur as small volumes disposed of at the samelocation over a period of time, the residual trail could be quite narrow, and,due to heterogeneities, would not necessarily be vertical. Location of theresidual DNAPL in such a trail by drilling or digging is extremely difficult,and is rarely accomplished at sites even when it is known from directencounters of pools that DNAPL exists at the site.

At some sites, DNAPL accumulations have been encountered during thedrilling of borings or the installation of monitoring wells. In fact, at somesites the drilling operation may have provided an avenue for furtherdownward migration of previously stationary DNAPL (e.g. Silresim, inLowell, Massachusetts). Even if DNAPL is not encountered during drilling,monitoring wells can be constructed to allow DNAPL, if present, to enterthrough the screen. Chemical analysis of soil samples can be used todetermine the presence of DNAPL. This direct evidence is obtained bypartitioning a total soil chemical analysis into the portions attributable to thesolids and the water, and in the case of unsaturated samples, the vapor phase.If such calculations yield a pore-water concentration that exceeds thesolubility of the compound, DNAPL is likely present in the sample. Thesolubility of pure tetrachloroethene in distilled water under laboratoryconditions is 150,000 micrograms per liter (Lig/1).

The solubility of individual DNAPL chemicals, however, can be substantiallyreduced by admixture of others such as petroleum oils (of which there isevidence at the OK Tool property) or by the presence of naturally occurringsubstances in the ground water such as iron and manganese. For example, aconcentration of 60,000 |ig/l tetrachloroethene was measured in thesupernatant ground water that was standing on top of a four foot thickaccumulation of preponderantly tetrachloroethene DNAPL in well UC8 at theWells G & H Site. Since this water had been in contact with the DNAPL forweeks (if not months), this example illustrates that the "field solubility" ofindividual compounds may be typically less by factors such as 2 to 3 than thelaboratory solubility.

DNAPL is not always encountered during drilling at sites where DNAPLchemicals have been disposed of or spilled. In addition, it is sometimes


Page 3


impossible to obtain reliable documentation of a spill. At such sites, thepresence of DNAPL must be inferred from chemical analyses. Two methodsare currently used to infer the presence of DNAPL. These methods, which arediscussed below, are the relationship between the measured concentrationand the solubility, and the persistence of the compound at purge wells.

If dissolved concentrations in ground water represent a significant fraction ofthe field solubility of the compound, DNAPL is likely present. Because of thedilution that occurs in flowing ground water, it is not necessary that thedissolved concentration be equal to the field solubility. In addition, onlysmall amounts of DNAPL need be present to cause dissolved concentrationsin ground water that approach the field solubility. For ground water flowunder natural conditions and DNAPL residual zones of centimeters in size,saturated concentrations would be expected.2. In many cases the length of themonitoring well intake zone can cause dilution and be a large factor indetermining the accurate concentration of the compound. Currently, aground water concentration of 5 to 10 percent of the field solubility of acompound is thought to suggest the nearby presence of DNAPL. Formonitoring wells with long intake zones and a high potential for verticalmixing, 1 to 5 percent of the solubility may be a more appropriate indicator ofDNAPL.2 In our experience, the concentrations at OK Tool are exceptionallyhigh to have come from such a long well screen, and given dilution, stronglyindicative of DNAPL.

The Wells G & H Site in Woburn, Massachusetts is a confirmed DNAPL site,and provides an excellent case history for the conditions at the Savage site.Tetrachloroethene product was found in a monitoring well beneath theUniFirst building. Ground water concentrations of tetrachloroethenedetected in wells located less than 400 feet down gradient of the source areawere found to be in the range of 10,000 to 20,000 |ig/l. These concentrationsare within the solubility guidelines presented above and are known, becauseof the position within the ground water flow path, to be directly related to thedissolution of the DNAPL.

If purge wells are installed to recover contaminated ground water, thecontinued presence of elevated dissolved concentrations may suggest the

2 Feenstra, S., Mackay, D.M., and J.A. Cherrv. in press. Presence of residual Nf APL based on organicchemical concentrations in soil samples. Submitted to Ground Water Monitoring Review, October 1990.

Section 4.0 finishes with a comparative analysis of the remedial alternatives. The

comparative analysis presents the differences among the alternatives. The comparative analysisidentifies the alternative that performs most effectively relative to cost for the Site: 1) pumping

contaminated groundwater at O.K. Tool and at the Hitchiner facilities; 2) treating thegroundwater at individual treatment plants at O.K. Tool and the Hitchiner facility; 3)

discharging the treated groundwater to the discharge stream or to the river; 4) controlling use of

the groundwater within the area of the Site that overlies the extended plume containing

compounds at concentrations above the cleanup goals through purchase and maintenance of

groundwater rights until the cleanup goals are achieved; 5) monitoring the ground and surface

water for changes in the configuration of the plume; 6) reporting to the EPA, NHDES and thecommunity; and 7) proposing and implementing EPA-approved modifications to the remedial

action as conditions change and warrant. This alternative provides for a combination of

engineering and institutional controls that are flexible, sensible and reliable solutions. Inaddition, the combination of controls provides for dynamic, ongoing and informal strategic

planning that will maximize inclusion of the evolving technologies that increase the rate of massremoval from the accumulation of DNAPL below the water table at the O.K. Tool facility while

protecting human health and the environment from exposure to the DNAPL below the water

table and to the contaminated groundwater that currently constitutes the plume, and providing

for an aggressive level of contaminant mass removal.

Institutional Controls

The NCP states that "EPA expects to use institutional controls such as water use and deed

restrictions to supplement engineering controls . . . to prevent or limit exposure" to

contamination at the site. Such controls may be used "as a component of the completed

remedy." 40 C.F.R. s300, 430(a)(iii)(D). Examples of institutional controls include (1)installation of alternative water supplies; (2) acquisition of real property; (3) regulatory

restrictions; and (4) restrictions on property rights. See EPA Guidance on Remedial Actions for

Contaminated Groundwater at Superfund Sites (December 1988). According to the EPA

Guidance, institutional controls should be implemented as part of the response action.In keeping with the NCP and EPA Guidance, institutional controls are included as part of

the management of migration alternatives to prevent exposure to contaminated groundwater at

the Savage Well Site. Currently, much of the groundwater at the Site is available for use for

industrial or agricultural purposes in its present condition and certain controls are already in

2176-160/HAZ/4910 4-2

place. Public water lines to businesses and residences surrounding the Savage Well Site have

been constructed, thereby eliminating the use of the Savage Well aquifer as a drinking water

supply for the Town of Milford. As noted in the RI, the only place where groundwater still may

be used for drinking water purposes is seasonal use at the Milford Drive-in. Alternative water

supplies to the Drive-In would be installed as part of the institutional controls at the site. Thus,

there would be no known use of the groundwater at the Savage Well Site for drinking water

purposes.

In addition, the Savage Well itself currently is owned by Hitchiner Manufacturing

Company, for use as an industrial water supply. Again, no water from the Savage Well now or

in the foreseeable future could be used for drinking water purposes. Further, current state law

prohibits the placement of new wells in areas like the Savage Well Site where the storage,

treatment or use of significant amounts of hazardous chemicals occurs "at any point tributary" to

the well. At the Savage Well Site, points tributary to the Well itself include gas stations, auto

body repair shops, agricultural uses and industrial operations. In addition, state regulations

prohibit siting certain public wells in areas subject to one hundred year flooding. The Savage

Well site is located in large part within the 100 year floodplain. Thus, state law provides an

existing additional institutional control preventing exposure to the contamination at the Site.

Local regulation provides an additional institutional control. The area where the PRPs are

located is zoned industrial. According to the Town of Milford zoning regulations, residential

dwellings are specifically excluded from the industrial district. Thus, future residential exposure

to contaminants at the industrial sites of the PRPs is, as a practical matter, prohibited. Local

zoning regulation also prohibits the siting of potable water supply wells in wetlands, which may

include parts of the Savage Well Site.

In addition to the institutional controls already discussed, other controls are to be enacted

to further restrict the possibility of using groundwater at the Savage Well Site for drinking water

purposes. These controls include deed restrictions preventing the use of groundwater for

drinking water purposes. Several of the potentially responsible parties, Hitchiner

Manufacturing, Hendrix Wire and Cable, and O.K. Tool, Inc., have agreed to enter into deed

restrictions preventing the use of groundwater at the premises for drinking water purposes. In

addition, the PRPs are approaching neighboring landowners comprising the bulk of property at

the Savage Well Site to purchase their groundwater rights for drinking water purposes. The

institutional controls described above, in combination with other remedial action, significantly

reduce if not eliminate the possibility for ingestion of contaminants at the Savage Well Site.

2176-160/HAZ/4910 4-3

• Compliance with ARARs;

Long-term effectiveness and permanence;

Reduction of toxicity, mobility, or volume through treatment;

• Short-term effectiveness;

• Implementability;

Cost;

• State acceptance; and

• Community acceptance.

As set forth in the NCP, the detailed analysis of alternatives is predicated on a "balancing"

of the first seven criteria listed above to arrive at acceptable remedies. The final two criteria -

state and community acceptance - are then used to modify the preference for a remedy.

Given their significance in the selection of the remedy, each criterion is described below

in terms of its application to the Savage Well site in the detailed analysis of alternatives.

Ovqfall Protection of Human Health and the Environment

This criterion is used to determine the degree to which an alternative provides adequate

protection of human health and the environment. Specifically, the detailed analysis process as

set forth in the October 1988 RI/FS Guidance evaluates the extent to which site risks would be

"eliminated, reduced, or controlled through treatment, engineering, or institutional controls". In

addition, the guidance states "it is important to note that protectiveness is achieved by reducing

exposure to acceptable levels but achieving these reductions and exposure might not always be

possible by actually cleaning up a specific medium to these same levels."»

Compliance with ARARs

Each alternative is evaluated relative to its attainment of federal and state ARARs as

identified during the RI/FS process. For the Savage Well Site, ARARs identified in Tables 2-2,

2-3, and 2-4 were used to conduct the detailed analysis for action-specific, location-specific, and

chemical-specific ARARs, respectively. Where an ARAR cannot be met, the RI/FS process

2176-160/HAZ/4910 4-6

provides a mechanism for obtaining a waiver. CERCLA provides two circumstances in which

an ARAR may be waived: when compliance with an ARAR is technically impracticable from an

engineering perspective and when an alternative remedial action will attain an equivalentstandard of performance by the use of another method or approach.

It should be noted that the foregoing two criteria (overall protection of human health and

the environment, and compliance with ARARs) will both be addressed in the ROD and

constitute threshold criteria which must be met by any selected remedy.

Long-Term Effectiveness and Permanence

This criterion addresses the risk remaining at a site following implementation of the

remedy. As set forth in the October 1988 RJ/FS Guidance, this criterion includes an evaluation

of the magnitude of the risks associated with remaining contaminants and residuals resultingfrom treatment. Additionally, each alternative is evaluated relative to the adequacy and

reliability of controls for long-term site management; this includes institutional as well as

engineering controls.

Reduction of Toxicity. Mobility and Volume Through Treatment

This criterion addresses EPA's statutory preference for remedies employing treatment

technologies that permanently and significantly reduce the toxicity, mobility, or volume of

hazardous constituents in environmental media. The detailed evaluation process as set forth in

the October 1988 RI/FS Guidance establishes specific factors to be considered, including the

degree to which each alternative will reduce the toxicity, mobility, and volume of contaminants,

and the degree to which such treatment actions are irreversible. Each alternative under

consideration is evaluated in terms of EPA's statutory preference for treatment as a means ofreducing site risks.

Short-Term Effectiveness

This criterion is used to evaluate the effects of each alternative relative during the

construction and implementation phase. The primary focus of this evaluation is a consideration

of the short-term human health and environmental effects of each alternative, and a

determination as to whether adverse impacts can be minimized or mitigated. As set forth in the

2176-160/HAZ/4910 4-7

October 1988 RI/FS Guidance, each alternative is to be evaluated relative to protection of the

community and on-site workers during remedial actions, and environmental impacts and

associated mitigative measures. Additionally, an estimate is to be made of the time-frame for

achieving remedial response objectives.

Implementability

The technical and administrative feasibility of implementation is evaluated for each

alternative. This evaluation includes consideration of technical factors such as anticipated

construction and operation difficulties, the reliability of the selected technology, the ease of

undertaking further remedial action (for example, to address subsequent operable units based

upon the results of monitoring of initial actions), and the ability to monitor the effectiveness of

the remedy. Administrative considerations include a determination of the need for coordination

with other offices and agencies to secure permits and approvals. Consideration is also given tothe availability to services and materials to implement each alternative.

Cost

The detailed analysis of costs for each alternative addresses not only the cost to implement

the remedy but, more importantly, the relationship between the cost and the associated benefits

in terms of reduction of human health and environmental risks. Elements of the cost analysisinclude determination of the alternative's capital cost (for example, construction, equipment,

land and site development) as well as O&M costs (for example, labor, materials, energy,

monitoring). Costs developed for the detailed analysis ("study costs") are normalized as

present-worth costs with an accuracy on the order of +50 percent to -30 percent. As such, they

do not represent cost at completion or construction cost estimates, but are intended to support a

systematic evaluation of each alternative from a cost-benefit perspective. By conducting a

sensitivity analysis, variables having the greatest impact on the cost can be isolated (for

example, the duration of a pumping and treatment alternative).

State Acceptance

This criterion addresses the state's technical and administrative issues and concernsrelative to each alternative. Input to this process is derived in part from comments received on

the RI/FS report and the subject of state acceptance is addressed by EPA in the ROD. To the

2176-160/HAZ/4910 4-8

extent that the state's preferences have been determined, they are incorporated into the detailed

analysis for this criterion. However, this criterion is primarily evaluated during the publiccomment period.

Community Acceptance

As with state acceptance, input to this criterion is derived in part from comments received

on the RI/FS report. To the extent that community preferences have been determined, they are

incorporated into the detailed analysis for this criterion. However, this criterion is primarily

evaluated during the public comment period.

In addition to the nine criteria mandated by the NCP and the RI/FS Guidance, a tenthcriterion was included in the detailed analysis of alternatives for the Savage Well Site:specifically, the duration of treatment times and flushing times. This criterion was added to

provide a common basis for comparison between the alternatives under consideration, asdescribed below.

4.2^2 Comparison of TlfilUUCflM TJ

In order to provide a comparative analysis of the estimated length of operation for each

management of migration alternative, and thus provide a basis for comparison of O&M costs, an

analysis of aquifer flushing times was used to estimate the time required to achieve a common

remediation level given the implementation of each of the alternatives.

The purpose of this comparative analysis of treatment times is to aid in assessing whether

the increased costs of alternatives involving treatment of the extended plume are warranted by

the increased protectiveness of these alternatives, as indicated by the decrease in the estimatedtreatment times.

The approach to the analysis was to evaluate concentration reduction in the aquifer both as

a result of recovery and treatment of groundwater and as a result of natural flushing in theportions of the aquifer outside the zone of recovery/treatment for each alternative. The method

of analysis is outline below.

Capture zones and resulting groundwater contours corresponding to the recovery well

pumping scenarios for each alternative were evaluated and presented in Section 3.0. Based on

the capture zones and groundwater contours, streamlines were drawn to depict: 1) the pathwaysof contaminants not captured by the source area wells but captured by the MM wells (i.e. from

the outside edge of the source area capture zones to the management of migration wells); and 2)

2176-160/HAZ/4910 4-9

A CllCOn* Company

EnvironmentalScience &Engineering, Inc.

File:491-5344.999Ref.:5347_2.svg

June 28, 1991

Mr. Daniel Coolidge, Esq.Sheehan, Phinney, Bass, and Green, P.A.1000 Elm StreetManchester, New Hampshire

Subject: Chromium Speciation at Savage Well Site

Dear Mr. Coolidge:

You have requested that Environmental Science and Engineering (ESE) consider the likelyvalence state and the fate of chromium that may exist in soils in the vicinity of the former OKTool Building at the Savage Well NPL Site. It is our understanding that the U.S. EnvironmentalProtection Agency is concerned about the potential for hexavalent chromium to be present, asit is more toxic than the trivalent form of chromium. Thus, the presence or absence ofhexavalent chromium in these soils is an important factor in deciding the necessity of remedialaction.

ESE has found little to suggest that chromium exists in the hexavalent form at the Site. Thefollowing- report describes the investigations and geochemical considerations that led to thisconclusion:

One Overlook Drive, Unit 16 Amherst, NH 03031 Phone (603) 672-2511

Formerly known as Hunter/bca.

Fax (603) 072-2014

THE NATURE OF CHROMIUM DEPOSITED IN THE VICINITY OF OK TOOL

The Remedial Investigation1 (Table 1-2) of the Savage Well Site provided information onchemical usage at OK Tool Company, Inc. (OK Tool). With the exception of the genericclassification, "paints," none of the chemical mixtures on the list (mostly cutting oils) would beexpected to contain hexavalent chromium. Only specific yellow-pigmented paint formulationscontain hexavalent chromium.

The RI (and previous studies) indicate that metal waste derived from OK Tool's manufacture ofmachinery were present in the soil adjacent to the former OK Tool facility. Oily substances,probably cutting oils, were also observed in soil during the field program and were associatedwith the metallic particles, a finding consistent with this waste management practice. Soilsamples with elevated detections of metals correlated with these areas. Thus, it would appearthat the valence state of chromium, as it was originally deposited to the land, could be surmisedfrom an understanding of the materials used and processes conducted at OK Tool.

A former OK Tool employee was interviewed and plant purchasing records reviewed todetermine the potential source of chromium in soil samples.

Specific operations will produce wastes containing hexavalent chromium (either as chromate(CKV2) or dichromate (Cr207'

2)), if chromic acid is utilized:

• Aluminum anodizing• Metal Engraving• Metal Etching• Electroplating• Metal Cleaning

Additionally, hexavalent chromium compounds are routinely added to cooling water to inhibitcorrosion, so chromates will appear in blow down streams. Finally, hexavalent chromiumcompounds are periodically used in the manufacture/formulation of brightly colored inks,industrial dyes, and paint pigments.

In view of this information questions relating to the processes and material used were posed toOK Tool employees to better understand/characterize the manufacturing operations performedat the OK Tool facility. Answers provided by the secretary at the facility and Attorney MaureenRaiche appear in bold face type:

1. What intermediate or finished products were produced by OK Tool (Metal cutting tools,wood working machines, metal grinding machines)

HMM Associates (1990) Remedial Investigation and Feasibility Study of the Savage Well Site.

ESE

Mr. Daniel Coolidge, esq.June 27, 1991PageS

2. Were any special coatings applied to these products at the facility? (Machines werepainted on site mostly with gray paint)

3. In addition to manufacturing machinery, were there any liquid storage tanks/drumslocated within the facility at any time? Were any liquid wastes handled or generated atthe facility? (One outside tetrachloroethene storage tank, one underground tankinside building)

4. What were some typical materials that were received on a regular basis at the facility?(List provided by Attorney )

5. Were any of the following specific metal treatment operations carried out at the site whenOK Tool was in existence?

a. Aluminum anodizing (No)b. Metal engraving (Some, part numbers only)c. Metal etching (No)d. Electroplating (No)e. Metal cleaning (Yes, with tetrachloroethene and a Hotsy

Tub washer®)

6. Were any paints/coatings/glazes specially formulated at the site? (No)

7. Did the OK Tool facility have any cooling-water systems or cooling towers?(Once-through, cooling water from the town was utilized for non-contact coolingpurposes)

8. Who occupied the site before OK Tool and what type of activities did they carry on?(Gasoline Service Station)

There are chromium wastes associated with certain manufacturing facilities. However, rawwaste inventories performed on manufacturing facilities engaged in "mechanical material removaloperations" (cutting) and "material coating operations", such as those carried out by OK Tool,

ESE

Mr. Daniel Coolidge, esq.June 27, 1991Page 4

have shown that the hexavalent portion of the waste is minimal. The median fraction ofchromium found to be in the hexavalent form was (EPA 1977):2

• 6.9% for material coating operations• 0.047% for mechanical material removal operations

Thus, based on the review of the OK Tool plant invoices and the answers to the submittedquestions, no major sources for hexavalent chromium appear to exist.

STABILITY OF CHROMIUM COMPOUNDS IN THE ENVIRONMENT

From the above discussion, it would appear that chromium waste at OK Tool was most likelyin the form of elemental or trivalent chromium. For hexavalent chromium to be present in thearea, interconversion between the trivalent and hexavalent state would have to have occurred.

Although hexavalent chromium should predominate under oxidizing conditions (e.g. in thepresence of atmospheric oxygen), chromium speciation is dependent on a number of interactingfactors, including: pH, Eh, presence of organic and inorganic binding ligands, availability andform of manganese oxides, and reducing organic substances (e.g., sulfides). The dynamics ofthe conversion can be substantially affected by altering these conditions (Bartlett and James,1988)3.

In this regard, the most important characteristic of chromium in the vicinity of OK Tool is thatit is likely derived from metal alloys in the form of relatively large particles (as indicated bytheir visibility). This attribute would limit the amount of chromium available for surfacereactions or solvation.

Chromium-containing alloys contrast with the chromium sources for which oxidation has beendemonstrated (e.g. soils; pure trivalent chromium salts; sludges and leather scrap fromchromium tannery operations). Further, the pH of soils sampled in the vicinity of OK Tool (4.5

2 EPA (1977) Controlling Pollution for the Manufacturing and Coating of Metal Products. EPA 625/3-77-009.

Bartlett, R.J. and B.R. James (1988). Mobility and Unavailability of Chromium in Soils, in Chromium in the Natural and HumanEnvironments J.O. Nriagu and E. Nieboer, editors. Wiley, New York. 571 pages.

ESE


- 5.0, measured by AMRO laboratories in the samples described in a subsequent section) arebelow those demonstrated by Bartlett and James (1979)4 to oxidize trivalent chromium (Bartlettand James indicate the pH should be above 5.0). The particular conditions in the vicinity of OKTool do not appear favorable for conversion of trivalent to hexavalent chromium.

CHEMICAL ANALYSIS OF CHROMIUM AND RELATION TO POTENTIAL HEALTHIMPACTS

The analytical findings for the Savage Well Site, as they relate to potential health impacts, alsomerit comment. The Baseline Health Risk Assessment for the Savage Well Site5 consideredexposure to chromium as a result of drinking water or making direct contact with soils. It ispossible to determine what hexavalent chromium concentrations in these media would be ofhealth concern.

As described below, concentrations of hexavalent chromium less than 0.1 milligrams per literin water (mg/1; the primary drinking water standard), or 900 milligrams per kilogram in soil(mg/kg; back-calculated from the risk assessment), would not be expected to have a healthimpact. Analytical results may be compared to these concentration limits.

Groundwater

Although groundwater in the vicinity of the former OK Tool facility is not used for humanconsumption, the Baseline Health Risk Assessment considered the potential for health impactfrom ingestion of potable water, as a possible future event.

The National Primary Drinking Water Standard (Maximum Contaminant Level; MCL) for totalchromium is 0.1 mg/1. This value is derived from a Reference Dose (RfD) for hexavalentchromium and standard values for the daily intake of drinking water. The standard is consideredto be fully protective of human health. The RfD for hexavalent chromium is a daily intake limitthat would be without toxic effects in humans. The RfD was calculated by dividing a no effect

Bartlett, J.R. and B.R. Jamei (1979) Behavior of Chromium in soils ID.: Oxidation. J. Environ. Qual. 8:31-35.

5 ESE (1991) Savage Well Project. Baseline Health Risk Assessment. Project No. 490-5227, March 20, 1991.

ESE


dose from a study in laboratory animals by a safety factor of one hundred6. The MCL alsoaccounts for the possibility that humans may be exposed to hexavalent chromium by other routes(e.g. diet) by limiting the drinking water intake to a level that would not provide the entire RfD.Although the MCL is applied to total chromium, it is based on the RfD for hexavalentchromium, and will be protective even if all the chromium in water is hexavalent.

No well in the vicinity of OK Tool exceeds the drinking water standard for total chromium.Total chromium concentrations were below the MCL for groundwater downgradient of thesuspected disposal area at the OK Tool facility. Total chromium concentrations measured inbedrock wells MI-22 and MI-25 were 0.088 and 0.026 mg/1, respectively. A groundwatersample from MW-24, screened in the overburden downgradient from the OK Tool disposal area,contained no detectable levels of chromium. The lack of positive detections for chromium inoverburden wells downgradient from the disposal area is evidence that the chromium measuredin soils at the disposal area have not affected the groundwater quality in the vicinity.

Only one groundwater sample obtained during the RI contained chromium at concentrationsabove the MCL. The concentration of total chromium in well MW-6A was 0.141 mg/1. MW-6A is located approximately 1000 feet southeast of the OK Tool facility, adjacent to the Bostonand Maine Railroad line. Groundwater table contour maps show the groundwater flow directionto be easterly to northeasterly from the OK Tool facility. MW-6A is crossgradient but notdirectly downgradient of the OK Tool facility. The chromium detected in MW-6A is most likelyfrom a source other than the OK Tool facility.

Soil

In the Baseline Health Risk Assessment, a hazard quotient of 16 was calculated for direct contactwith soils in the vicinity of OK Tool, under the assumptions that the area was being used forpurposes that would promote frequent contact (resulting in inadvertent ingestion) in youngchildren, and that the soil contained hexavalent chromium at a concentration equal to the highestconcentration of total chromium detected in the area (15,100 mg/kg). A hazard quotient inexcess of one is generally considered unacceptably high. Because exposure is linear inconcentration, it is possible to calculate what concentration would result in exposure producinga hazard quotient of 1, simply by dividing the chromium concentration by 16. Thus, even ifhexavalent chromium were present in soil, it would not be expected to have an effect on healthunless concentrations were in excess of approximately 900 mg/kg (15,100/16 = 943).

Integrated Risk Information Service, on-line database, accessed June 26, 1991.

E5E


On the 13th of May, 1991, 5 soil samples were taken by ESE at the Savage Well site fordetermination of hexavalent chromium. Four samples were taken from areas where high totalchromium concentrations were detected during the RI, and a background sample was obtainedfrom a location nearby. Samples were composited and split with a representative of the Stateof New Hampshire Department of Environmental Services (NHDES). Samples taken by ESEwere labeled and transported on ice to AMRO Environmental Laboratories (splits were taken tothe NHDES laboratory).

AMRO Laboratories and the State followed a Special Analytical Services (SAS) protocolprovided by EPA in extracting samples and analyzing for hexavalent chromium. However,using the alkaline digestion method required by the SAS, reproducible analysis could not beaccomplished. AMRO reported recovery of hexavalent chromium from spiked samples wasoutside the required limits (from 29 to 45%; required recovery is 75 - 125%). Additionally,substantial interference of the analytical method by iron, hydrocarbons, and, to some extent,manganese was encountered. Due to these difficulties, no analytical findings were reported forthe samples treated as prescribed in the SAS.

AMRO also conducted an alternative digestion, using a slightly alkaline (pH 7-8) solution ofsodium hydroxide/sodium carbonate. The remainder of the analysis was conducted accordingto the SAS. Using this method, AMRO achieved recoveries of 65 to 71% in spiked samples,and reduced interference. This is near to, but still lower than, the required recovery of 75 -125%. No hexavalent chromium was detected in any sample above the detection limit of 10mg/kg.

EPA has begun a review of the suitability of the alternative approach, that is not complete asof this writing. It should be noted however, that the detection limit required by the SAS issubstantially below the health protective limits. Recoveries and/or detection limits in excess ofthe original requirements may still leave an ample margin of safety. Thus, while the results stillawait approval of EPA, they are encouraging when taken in the context of health-basedconcentration limits.

SUMMARY

In summary, ESE did not find any indication of a source of hexavalent chromium in the vicinityof the former OK Tool building. Rather, past studies conclude that metallic shavings exist inthe soil and, it is likely that this form would not favor the formation of the hexavalent state,particularly given the measured pH of the soil. Total chromium analyses in groundwater inobservation wells near the metal disposal area do not indicate a potential for health impact.

ESE

Mr. Daniel Coolidge, esq.June 27, 1991PageS

Analyses of hexavalent chromium in soil that would support the opinions described in the presentreport are currently being reviewed by the EPA.

If you have any questions, please feel free to call.

Sincerely,ENVIRONMENTALSCIENCE & ENGINEERING

Bradley W. Schwab, Ph.D.Associate Vice President

cc: Richard Goehlert - EPAMark Rouvalis - McLane Law FirmMaureen Raiche - Devine and Nyquist

E5E

4.4

The detailed analysis of management of migration alternatives considers remedial

objectives for two portions of the contaminant plume: the concentrated plume and the extended

plume. The analysis recognizes that the plume of contaminated groundwater is persistent

because of continued dissolution of the concentrated dissolved VOC contamination and residual

DNAPL below the water table at O.K. Tool. Additionally, areas of locally elevated

concentrations of dissolved VOC contamination at Hitchiner and in the vicinity of MW-20 are

also considered in the analysis as concentrated areas of the plume that provide continued

migration of contaminants to the aquifer, although existing data do not definitively indicate the

presence of DNAPL below the water table.

The remainder of the dissolved contaminant plume is considered as an extended plume of

dilute contaminated groundwater in a highly permeable unconfined aquifer.

Eight Management of Migration alternatives were evaluated, including a No Action

(MM-1) and a Limited Action (MM-2) alternative.

(The components of the Limited Action alternative (MM-2); which include institutional

onTrols consisting of restriction and management of the use of the contaminated portion of the

aquifer, long-term monitoring to characterize changes in contamination over time, and formal

site reviews at five year intervals to assess the effectiveness of the remedy, are carried through

all of the subsequent alternatives. The use of institutional controls as a component of the

remedial alternative is discussed in greater detail within the discussion of alternative MM-2.

/^~ Alternative MM-3 provides for remediation of the concentrated plume areas by one of four

/ combinations of approaches (MM-3A through 3D) based on the results of pre-design and design

' analysis. Given the site characteristics, available alternatives for the recovery and treatment of

DNAPL are limited. The principal approach is groundwater extraction and treatment to prevent

migration of contaminants to downgradient portions of the aquifer. However, Alternative MM-3

\ allows for additional data collection, analysis, and modelling during the pre-design and design

\ phases in order to refine the approach to treatment of the concentrated plume and DNAPLs so as

to result in a more effective and cost efficient alternative.

Long term pumping of groundwater in the concentrated plume areas and treatment of the

extracted groundwater are designed to comply with ARARs at the point of discharge or to meet

appropriate contaminant levels for recharge to the aquifer, either downgradient or upgradient of

the residual source areas.

2176-160/HAZ/4910 4-18

4 4.1 Al*M-nfltTve MM-li No Action rMaT>ap<^nent of Mignuion)

Description

Management of Migration Alternative MM-1, No Action, provides for long-termmonitoring of the contaminant plume. This alternative involves no treatment, containment,volume reduction, or institutional controls. However, as discussed above, it is important to note

that the no action alternative is based on and includes all past remedial action that has taken

place at the site. At this site, numerous activities, including source removal and modifications of

materials management practices, have been undertaken to mitigate the contaminants and impacts

from the contaminants. Many of the remedial objectives called out in the EPA guidance and in

the NCP have for a great part been achieved up to this point. Actions completed at the siteinclude: 1) there is no current use of the groundwater for potable purposes except for seasonal

use at the Milford Drive-in; 2) a fully adequate alternative water supply has been provided to

users within the site; 3) most of the aquifer in the site and site area is of adequate quality to be

used for agricultural, industrial and potable drinking sources. (In fact the aquifer is currently

heavily used for various purposes); 4) the site and site area is a heavily industrialized andcommercial area; 5) Hitchiner Manufacturing has purchased and currently owns the former

Savage Well for future use as an industrial water supply; 6) none of the PRP currently use

tetrachloroethene in their processes and the PRP's materials handling and manufacturing

processes have been substantially modified to minimize the potential release of any hazardous

materials, including the cessation of discharge from Hendrix and reduction and modifications of

the discharge from Hitchiner; 7) source control through soil removal and off-site disposal has

been accomplished at the primary source area, O.K. Tool.

MM-1 would consist of a comprehensive sampling and analysis program to address

groundwater and surface water. At five year intervals, the regulatory agencies will review the

results of the sampling and analysis program and decide whether the program should be

expanded, reduced, or discontinued. The sampling and analysis program is expected to continuefor thirty years.

The major work items associated with this alternative are as follows:

• Conduct a long-term groundwater, surface water and sediment sampling and

analysis program to monitor changes in groundwater and surface water quality.

• Perform a site re-evaluation every five years.

2176-160/HAZ/4910 4-20

The No Action alternative provides for continued monitoring only. It has been retained

and evaluated in detail to establish a baseline to which all other alternatives are to be compared

as required by the NCP. It should also be noted that the components of the No Actionalternative are carried through as components of all other MM alternatives.

Evaluation

Overall Protection of Human Health and Environment

Protection of human health and the environment is provided by activities completed to

date at the site, as previously discussed. Additional protection of human health and the

environment would be achieved by long-term monitoring, public informational programs, andperiodic site reviews.


Since MM-1 is a No Action Alternative, action-specific ARARs identified in Section 2.0,Table 2-2 are not applicable, beyond those requirements pertaining to groundwater monitoring,

which would be a key element of this alternative. Additionally, worker training requirements

would be met for on-site workers as necessary to conform with OSHA and SARA requirements.

Location-specific ARARs relating to future communications with applicable agencies will

be met through periodic review of monitoring results. Other location-specific ARARs identified

in Table 2-3 would not be applicable to the No Action Alternative.

Chemical-specific ARARs for state and federal MCLs are not currently met and would not

be met in the foreseeable future for groundwater under the No Action Alternative. Clean WaterAct Ambient Water Quality Criteria are currently met and would continue to be met for the

Souhegan River; this would be verified through long-term monitoring.


The No Action alternative would not remove, treat, or contain contaminants in the

groundwater, surface water, or sediments.

This alternative would require long-term sampling and monitoring. Under the SuperfundAmendments and Reauthorization Act (SARA), a five-year review would be required to evaluate

site conditions.

2176-160/HAZ/4910 4-21

flUG 91 14:02 FROM HMM flSSOC PflGE.002

LETTER OF TRANSMTTTAL

DATE: April 29,1991

TO: R. GoehleitU.S. EPAHSN-CAN540 Canal Street, Boston, MA 02203

FROM: Mark O. HeubergerHMM Associates, Inc.196 Baker AvenueConcord, MA 01742

RE: Savage Well Site JOB NO.: 2176-160

SUBJECT: Additional Alternative/Cost Estimate Revisions

For Your InformationPer Your Request

For Your Review/CommentsFor Your Authorization

REMARKS:

As discussed in our 4/26/91, HMM's responses to the costing issues raised in the 4/4/91EPA-REEL letter are as follows:

Item 1: QAM CostsJbtElectricity

EPA-REEL questioned the O&M costs for electricity. Using the cost table for MM-3B(Table 4-11), EPA-REEL estimates a power requirement of 130 hp or $84,900/year.

HMM has recalculated the costs for MM-3B (Table 4-11), the example cited in the letter,as follows:

The total horsepower requirements of the system (including an assumed total airstripper power requirement of 42 hp as specified in the EPA-REEL letter) is asfollows:

• Q.K. Tool/MW-20

Recovery pumpTransfer pumpAir compressor pumpTransfer pumpAir stripper/blowerDischarge pump

15 hp1

15 hp7.5 hp15 hp21 hp15 hp

XXXXXX

242414

==3S

=as=

306015602160

Hitchinar

Recovery pumpTransfer pumpAir compressor pumpTransfer pumpAir stripper/blowerDischarge pump

Subtotal 246

7.5 hp1

5hp7.5 hp

5hp21 hp5hp

x 1x 1X 1X 1X 1X 1

Subtotal

TOTAL

7.557.55

21= 5

51

2971 Selection based on Grundfos pump performance curves.

2176-160/HAZ/5213 - 4/29/91

f t U G 9 ' 9 1 14:03 F R O M H M M S990C P A G E . 0 0 3

-2-

Assuming an efficiency (n) = 70% yields an electrical horsepower of 424 ehp.

Multiplying this figure times the conversion factor of .7457 yields an estimated kilowattpower of 316 kW.

An additional estimated power requirement of 7.6 watts per square foot of building spacefor lighting, devices, HVAC, and miscellaneous was obtained from Means Electrical.Using the estimated total building size of 33,750 fr yields a power requirement of 256kW. Adding this figure to the previous total of 316 kW yields 572 kW. Assuming 10%additional power for contingencies, we recalculate the total power requirement to be629.75 kW. This corresponds to a yearly use of approximately 5.5 million kW or$550,000.

HMM has also recalculated the costs for MM-3A (Table 4-8);

The total horsepower requirements of the system are as follows:

O.K. Tool

Recovery pump 15 hp* x 1 = 1 5Transfer pump 15 hp x i = 15Air compressor pump 7.5 hp x 1 = 7 , 5Transfer pump 15 hp x 1 = 15Air stripper/blower 21 hp x 1 = 2 1Discharge pump 15 hp x 1 « 15

Subtotal 88.5

* Hitchiner

Recovery pump 7.5 hp x 1 =Transfer pump 5hp x 1 =Air compressor pump 7.5 hp x 1 =Transfer pump 5hp x 1 =Air stripper/blower 21 hp x 1 =Discharge pump 5hp x 1 =

Subtotal 51

TOTAL 139.5

Assuming an efficiency (n) = 70% yields an electrical horsepower of 199 ehp.

Multiplying this figure times the conversion factor of .7457 yields an estimated kilowattusage of 149 kW.

An additional estimated power requirement of 7.6 watts per square foot of building spacefor lighting, devices, HVAC, and miscellaneous was obtained from Means Electrical.Using the estimated total building size of 22,500 ft2 yields a power requirement of 171fcW. Adding this figure to the previous total of 149 kW yields 320 kW. Assuming 10%additional power for contingencies, we recalculate the total power requirement to be 352kW. This corresponds to a yearly use of approximately 3.08 million kWh or $308,000.

2176-160/HA275213 - 4/29/91

f lUQ 9 ' 9 1 1 4 : 0 3 FROM HMM PiSSOC PPGE . 004

-3-

Based on reaching a consensus on the assumptions to be used In these power estimates,HMM will revise this line item for the various alternatives.

Item 2: Treatment Plant Operators

HMM assumed a 24 hr/day operator at $50/hour and a 8 hr/day supervisor at $75/hour toprovide for a conservative level of safety given the size of the plants.

EPA-REEL recommends that the cost estimate assume 2 people on a day shift of 5 daysper week with some weekend oversight (HMM assumes this to mean 5 8 hr/days for 2people and 2 8 hr/days for 1 person). It is HMM's opinion that this level of oversight isless than desirable.

EPA-REEL also recommends that the cost estimate assume a labor rate of $30/hour. It isHMM's opinion that this is a low rate for a skilled treatment plant operator.

However, given EPA-REEL 's assumptions, the revised annual O&M cost for thetreatment plant operator is as follows:

$30/hour x 96 rnanhours/week x 52 weeks/year = $149,760

Based on discussions with EPA at our 4/26/91 meeting, the revised cost estimates willassume 24 hr/day operator and a 8 hr/day supervisor and will assume hourly rates asprovided by NHDES based on the treatment plant at Gilson Road.

Item. *

EPA-REEL has indicated that they consider the level of effort and costs of the monitoringprogram to be excessive. EPA Region I has also made this comment and has outlined aspecific sampling program to be used in the cost estimates (see 4/22/91 comments, page5). HMM agrees to make this change.

Item 4: Metals Removal

HMM agrees that the cost estimates for removal of off-site residuals is speculative, sincethe need for and the methods to be used for metals control must be determined throughsite-specific bench scale testing. However, EPA Region I requested that a line item costestimate be provided for disposal of residuals. The cost estimate is based on an estimatedmass of residuals derived by mass balance calculations and disposal costs for a RCRATSD facility.

Signature M Date

COMMENTS:

Signature Date

2176-160/HA2/5213 - 4/29/91

T n T Q i D Cj c; IT <7t <TI 1 -u

4.4J2 Altera^five MM-2

Description

In addition to the components of the No Action alternative, the Limited Action Alternative

MM-2 includes institutional controls which provide for controlled and appropriate restrictions of

groundwater uses to those that are consistent with the concentrations of dissolved chlorinated

hydrocarbon compounds detected in the groundwater. The currently employed institutional

controls, consisting of provision of a new drinking water supply and purchase of the old Savage

Well, would be augmented by purchase of the groundwater rights in the areas of the site that are

underlain by groundwater that contains volatile organic compounds above the target clean-up

levels. Much of the contaminated portion of the aquifer is currently usable for industrial and

agricultural purposes. In addition, much of the aquifer is currently usable for potable purposes.

Restriction and management of the continued use of the contaminated portion of the aquifer

would be effected through the institutional controls in the form of purchase of the groundwater

rights in the plume area in which the concentrations of the compounds of concern are greater

than the clean-up goals. Control of the groundwater rights would be maintained only as long as

contaminant concentrations in groundwater exceed clean-up goals.

In addition to these institutional controls, this management of migration alternative

includes a long-term monitoring program. This long-term monitoring program would consist of

annual sampling and analysis of groundwater and surface water. In addition, quarterly sampling

would be performed at high sensitivity locations such as at the discharge zone at the east end of

the plume. The program would set forth sampling locations that would provide for adequate

density and location of sampling points to detect and characterize changes in the configuration

of the plume and changes in surface water chemistry. The surface water monitoring points

would include up to six locations along the Souhegan River and at appropriate tributaries to the

Souhegan. The groundwater sampling locations would be selected based on the results of

previous groundwater sampling completed at the time of submission of the long-term monitoring

work plan during the remedial design phase of the work. The costing of this alternative assumes

that there will be thirty-four groundwater sampling points and six surface water sampling points.

The major work items associated with this alternative would include:

• Purchase of groundwater rights over the mapped area of the contaminated

groundwater plume;

• Conduct long-term groundwater and surface water sampling and analysis;

2176-160/HAZ/4910 4-24

Report to the EPA and NHDES and the community on the results and

recommendations derived from the results of the groundwater and surface water

sampling program; and

Implement public informational programs including meetings and presentations to

assure that the public's awareness of the nature of site contamination is consistent

with current technical information.

Perform formal site reviews at five year intervals pursuant to the EPA

requirements.

Pf9t?ction of Human Health and the Environment

The Limited Action alternative would entail no removal or containment or treatment of the

contaminated groundwater or surface water but provides added protection over the No Action

alternative by restriction and management of the use of the contaminated portion of the aquifer.


This Limited Action Alternative provides for an alternative water supply and institutional

controls to prevent the future use of the aquifer for drinking water purposes. Action- specific

ARARs associated with this alternative include periodic groundwater monitoring to meet state

hazardous waste facility monitoring requirements, worker health and safety training to meet

OSHA and SARA requirements, preparation of a public information plan, and fencing of

portions of the site. Other action-specific ARARs identified in Table 2-2 would not be triggered

by this alternative.

Location-specific ARARs associated with this alternative would be limited to fence

construction in or along the Souhegan River or its floodplain. Such actions would have to

conform to state and floodplain regulations and orders.

In terms of chemical-specific ARARs, the Limited Action Alternative is not expected to

meet state and federal MCLs in the foreseeable future for groundwater. Clean Water Act

Ambient Water Quality Criteria are currently met and would continue to be met for the

Souhegan River; this would be verified through long-term monitoring.

The compliance of Alternative MM-2 with ARARs is summarized in Appendix VHI.

2176-160/HAZ/4910 4-25

4.6 COMPARATIVE ANALYSIS OF ALTERNATIVES

The purpose of this section is to compare the relative performance of each alternative in

relation to EPA's evaluation criteria. This comparative analysis is designed to identify the

advantages and disadvantages of each alternative relative to one another to highlight trade-offs

for decisionmaking.

4.6.1 Soorce Control Alternatives

For source control, no comparative analysis is needed. Given existing site conditions, the

No Action alternative meets the identified remedial objectives. No other alternatives have been

developed.

SC-1 - No Action

The No Action alternative for source control is retained based on the minimal potential for

impact to human health or the environment posed by residual contaminants in soils or sediments,

traditionally defined as "sources," as indicated by: 1) the Baseline Risk Assessment; 2) the

Ecological Risk Assessment; and 3) leaching calculations performed to determine the potential

impact of residual soil concentrations or groundwater quality. Although the alternative is

designated No Action in keeping with the EPA guidance because no additional treatment or

removal of source materials is involved, the analysis takes into consideration the fact that

significant activities, including removal of the principal PCE source at O.K. Tool and

modifications of materials management practices at Hitchiner and Hendrix, have already been

completed to mitigate the contaminants and potential impacts from the contaminants.

These activities, incorporated into the No Action alternative, have substantial value in

overall protectiveness, reduction of toxicity, mobility, and volume of contaminants; and in

long-term effectiveness and permanence.

4.0.2

Eight Management of Migration alternatives were evaluated, including a No Action

(MM-1) and a Limited Action (MM-2) alternative. The other six alternatives use various

combinations of groundwater extraction/treatment and hydrodynamic controls along with natural

attenuation to achieve target clean-up levels in the plume.

2176-160/HAZ/4910 4-148

For management of migration, only one contaminated medium exists, groundwater. The

site characteristics dictate that all remedial alternatives rely on a limited set of technologies,

primarily groundwater extraction/treatment and hydrodynamic controls. Consequently, all of the

developed alternatives have many components in common. Essentially, the comparison of

management of migration alternatives rests primarily in the trade-off of significantly increasedcost associated with increased levels of groundwater extraction and treatment.

A comparative analysis of treatment times and flushing times has been developed to aid in

the comparison of alternatives. This analysis provides a means of assessing whether the

magnitude of the increased costs of management of migration alternatives for treatment of the

extended plume are warranted by the degree of protection and increased effectiveness, as

indicated by reduction in estimated remediation times, of these alternatives versus that provided

by treatment of the concentrated plume and DNAPLs, restriction of groundwater use within the

extended plume, and long-term monitoring with periodic site review.

First, a comparative analysis of relative remediation time and corresponding operating

times for groundwater recovery/treatment has been developed for each alternative. Secondly,

the analysis of flushing times to achieve remediation levels in the portion of the aquifer outside

the area of treatment for each alternative provides a comparison of the protect!veness and

long-term effectiveness of the various management of migration alternatives.

The methods of analysis and the assumptions used in the analysis of remediation and

flushing times have been previously discussed in Section 4.2.2. It should be noted that clean-up

times can be estimated only; they will be further determined by observation of the actual

operating systems. Accordingly, the estimates presented herein are intended only to provide a

comparison of relative times to aid in the comparison of alternatives.

The results of the treatment time and flushing time calculations are presented in Table

4-24. The table presents estimated treatment times and flushing times to attain contaminant

levels of 5 ug/1, 10 ug/1, 50 ug/1, and 100 ug/1 as well as estimated times to attain a 90%

reduction in contaminant levels. Note that on Table 4-24, remediation times are presented for all

streamlines for 5 ug/1 and the streamlines which require the longest treatment and flushing times

for each alternative are used to estimate times for the other contaminant levels. Two sets of time

estimates are presented based on assumed retardation factors of 8.3 and 2.0. The times for the

determining streamlines only are presented for each alternative. The streamlines are depicted on

figures included as Appendix V.

2176-160/HAZ/4910 4-149

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The results of the calculations for 90% contaminant reduction can be compared with

results of the soil column flushing studies (Appendix IV), which indicate that 8-12 flushes arerequired to attain a 90% reduction in contaminants given an initial concentration of 1000 ug/1.

The calculations for 90% removal presented in the summary table indicate that approximately 14

to 20 flushes may be required, depending on the initial concentration, assuming a retardation

factor of 8 and approximately 5 to 10 flushes assuming a retardation factor of 2. Both the soil

column studies and the remediation time calculations indicate an asymptotic decline in the rate

of contaminant reduction with time and descending contaminant levels. Figure 4-28 illustrates

this asymptotic contaminant concentration versus time relationship for streamline A2 under the

MM-3 alternative for a retardation factor of 8.

The estimated treatment times were used to derive an O&M cost from the cost sensitivity

curves (see Section 4.5) for each of the management of migration alternatives. These time and

cost estimates are discussed in the following comparison of alternatives.

Qv?rflJll Protection of Human Health and the Environment

In a general sense Alternatives MM-3 through MM-8 are roughly equivalent in overall

protection of human health and the environment. All six alternatives provide a basic level of

protection by virtue of the existing alternate water supply and implementation of institutional

controls such as purchase of groundwater rights in the contaminated plume area. In addition, all

six of these alternatives include active groundwater extraction and treatment to limit further

contaminant contributions to downgradient portions of the extended plume, thereby reducing the

time required for attainment of target clean-up levels throughout the aquifer over time.

As shown in Table 4-25, the time required for the extended plume area to achieve target

clean-up levels is on the order of several decades for all alternatives. Alternatives that includesome extraction/treatment in the extended plume (MM-5 and MM-6) could decrease overall

clean-up time by 5 to 15 years over those without treatment of the extended plume (MM-3 and

MM-4). Alternatives that include significant extraction/treatment in the extended plume (MM-7

and MM-8) could decrease clean-up times by 5 to 10 years.

In all cases, the potential risk posed by the contaminated groundwater is addressed by

virtue of the associated institutional controls.

Alternative MM-2 (Limited Action) is deemed less protective than MM-3 to MM-8

because it includes no mechanism to limit continued contaminant contributions to downgradient

portions of the plume. It does, however, provide the overall protection of the institutional

controls to eliminate risks from potential future groundwater use.

2176-160/HAZ/4910 4-152

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Alternative MM-1 (No Action), requiring only monitoring, is the least protective of the

environment although human health risks are controlled by institutional controls already in placeand by source removal actions previously undertaken.


Alternatives MM-3 through MM-8 all provide a means to achieve chemical-specific

ARARs or target clean-up levels in the extended plume over time. As noted previously, MM-7

and MM-8 would achieve this somewhat sooner than MM-5 and MM-6 which, in turn, achievethis sooner than MM-3 and MM-4.

Neither MM-1 (No Action) or MM-2 (Limited Action) will achieve chemical-specificARARs in the plume.

Those alternatives requiring treatment (MM-3 through MM-8) would achieve required

target discharge limits in the treated wastewater using the same approach to treatment (metalsremoval/air stripping/vapor phase carbon or biological treatment).

Alternatives MM-3 through MM-8 include most of the same components and would beexpected to achieve action-specific and location-specific ARARs in much the same way.


Alternatives MM-3 through MM-8 are all judged to have similar long-term effectivenessand permanence. All six alternatives anticipate long-term treatment for the concentrated plume

in conjunction with institutional controls that would be maintained until target clean-up levels

are attained. The residual risk for all alternatives is essentially the same and related to the

ability of the extraction/treatment technology to reduce contaminant levels in the concentrated

plume area. It is believed that separate phase liquids (i.e. DNAPL) exist in this plume area.

Some residual risk may remain in those areas for an indefinite time, requiring the concentratedplume extraction/treatment component to operate indefinitely.

MM-2 is judged to have a lower long term effectiveness because it does not provide a

means for limiting continued migration of contaminants from the concentrated plume to the

extended plume. However, residual risk is managed by effective institutional controls. For

MM-1, residual risk at the site is essentially equal to the current risk for the foreseeable future.

The proposed control systems (extraction/treatment and hydrodynamic controls) are

generally effective and reliable for the operations required. Each alternative with increased

components would be somewhat less reliable due to the increased complexity associated with

2176-160/HAZ/4910 4-154

more treatment units (MM-5 through MM-8). Also, the management controls required for

MM-5 through MM-8 would exceed those for MM-3 and MM-4 because of the additional

extraction/treatment components.

MM-2 would be reliable in the context of the institutional controls which are a component

of MM-3 through MM-8 as well. Purchase of groundwater rights and maintenance of the

alternate water supply provides a reliable control component of MM-2 through MM-8.

Reduction of Toxicityf Mobility or Volume Through Treatment

Alternatives MM-3 through MM-8 use similar technologies to treat the contaminated

groundwater. Two treatment options have been carried through the analysis as representative of

those that could be selected during design. The first option is metals removal/air stripping/vapor

phase carbon and the second option is biological treatment via constructed wetlands.

The alternatives are estimated to remove the following amounts of contaminants from

groundwater:

MM-8

MM-7

MM-6

MM-5

MM-4

MM-3

2290 Ibs/yr

2280 Ibs/yr

2050 Ibs/yr

2030 Ibs/yr

1920 Ibs/yr

1920 Ibs/yr for 3A2650 Ibs/yr for 3B

120 Ibs/yr for 3C850 Ibs/yr for 3D

The amounts estimated for MM-4 through MM-8 assume that the concentrated plume

treatment selected is as described for MM-3A. If 3B or 3D are selected during design, the

estimated amounts shown above for MM-4 through MM-8 would all increase by 730 Ibs/yr.

For Alternatives MM-3 through MM-8 the overall reduction in toxicity, mobility and

volume will eventually be the same when target clean-up levels are achieved. As discussed in

Section 4.6.2.1, the differences among the alternatives are primarily related to the time to

achieve target levels.

MM-1 and MM-2 do not reduce toxicity, mobility or volume through treatment and do not

satisfy the statutory preference for treatment as a principal element.

2176-160/HAZ/4910 4-155

Short-Term Effectiveness

All the alternatives are expected to have similar short-term effectiveness. None of theremedial actions proposed have potential to impact the local community or remediation workerswho are properly trained. There is a somewhat greater potential for environmental impact for

MM-4 since the proposed hydrodynamic control would result in discharge of untreated water.

However, monitoring would assure that discharges to the river would not cause the river to

exceed Ambient Water Quality Criteria.

Alternatives MM-3C and 3D require pumping river water for injection into the

groundwater to form the proposed hydrodynamic barrier. This pumping process would be

designed to assure minimal impact on the river.

The times required until the remedial response objectives are achieved are discussed inSection 4.6.2.1 and presented in Table 4-25.

Implementability

Alternatives MM-3 through 8 are all readily implementable. All the alternatives rely on

essentially the same types of technology. Clearly, the alternatives which add treatment units in

the extended plume area (MM-5 through MM-8) will be somewhat more difficult to implement

because of the additional equipment installation.

Alternative MM-4 may be somewhat more difficult to implement than the others due to

the additional design and operational control needed for the hydrodynamic system. This

alternative would also require additional coordination with NOAA and U.S. Fish and Wildlife

because of the discharge of untreated groundwater to the river.

Alternatives MM-3C and MM-3D would also require additional coordination with NOAA

and U.S. Fish and Wildlife because of the use of river water to establish the hydrodynamic

barrier at O.K. Tool.

Cost

The cost comparison is a critical element in this analysis. As discussed throughout this

comparative analysis section, the only differences of interest among the alternatives are the

relative differences in time to achieve target clean-up levels in relation to the additional cost.

Table 4-25 presents a comparison identifying the relative cost increases associated with

relatively small reductions in the time to achieve target clean-up levels based on present worth

(30 years @ 10%) cost using: 1) air stripping with vapor phase granular activated carbon

(GAC); 2) biological treatment with revenues from septage intake; and 3) biological treatment

with no revenues from septage intake.

2176-160/HAZ/4910 4-156

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For example, based on the present worth cost using air-stripping with vapor phase GAC,

Alternatives MM-7 and MM-8 would achieve target clean-up levels at about the same time.

However, MM-8 has a cost that is higher by about $8,875,000. Given that there is no increase in

overall protectiveness, MM-8 should be eliminated from further consideration.

MM-7 would reduce the time to clean-up relative to MM-5 and MM-6 by about 5 to 10

years at an incremental cost of about $3,000,000; and by about 10 to 20 years relative to MM-3A

and MM-4 at a cost differential of about $8,500,000.

MM-5 and MM-6 would reduce the time to clean-up relative to MM-3A and MM-4 by

about 5 to 15 years but this is accomplished at a cost differential of about $5,000,000.

Summary

The analysis of alternatives provides a comparison of the relative cost-effectiveness of

implementing treatment of the extended plume over and above treatment of the concentrated

plume/DNAPL areas and control of groundwater use in the extended plume. Table 4-25

summarizes the present worth costs for alternative MM-3 and for each of the other alternatives.

The table also summarizes relative treatment times of each alternative and the projected costs

associated with these estimated times. Finally, the table presents comparative costs for the

alternatives with the air stripping treatment scenario and the biological treatment scenario, with

and without revenues from septage treatment.

Implementing Alternatives MM-5, MM-6, MM-7, or MM-8, rather than Alternative

MM-3, would result in a significant increase in costs while resulting in a relatively small

decrease in the time to achieve the specified contaminant levels throughout the aquifer, and a

relatively small increase in mass removal and in overall satisfaction of the evaluation criteria.

Given the level of protectiveness provided by MM-3 (including the institutional controls

on future groundwater use), the incremental benefits associated with the recovery and treatment

of downgradient portions of the aquifer through alternatives MM-5 through MM-8 would not

appear to justify their significantly greater costs.

The analysis also indicates that biological treatment may significantly reduce the costs of

the alternatives, assuming revenues from septage treatment.

The comparative analysis suggests that Alternative MM-3 performs the best for the site:

1) pumping contaminated ground water at O.K. Tool and at the Hitchiner facilities; and, if

warranted by pre-design studies, at an additional location near MW-20; 2) treating the ground

water via air-stripping or biological treatment systems; 3) discharging the treated groundwater to

the Hitchiner-Hendrix discharge stream or to the river, 4) controlling use of the ground water

2176-160/HAZ/4910 4-158

within the area of the site that overlies ground water that contains compounds at concentrations

above the clean-up goals through purchase and maintenance of groundwater rights until the

clean-up goals are achieved; 5) monitoring the ground and surface water for changes in the

configuration of the plume; 6) reporting to the EPA, NHDES and the community; and 7)

proposing and implementing EPA-approved modifications to the remedial action as conditions

change and warrant. This alternative provides for ongoing strategic.planning that will maximize

inclusion of the evolving technologies related to remediating DNAPL below the water table

while protecting human health and the environment from exposure to the contaminated ground

water that currendy constitutes the plume, and providing for an aggressive level of contaminant

mass removal.

2176-160/HAZ/4910 4-159

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