OU4 FOCUCED FEASIBILITY STUDY (FS) REPORT

US Army Corpsof Engineers

BALTIMORE DISTRICT JANUARY 2002

OU-4 Focused Feasibility Study ReportGreenwood Chemical Company

Superfund SiteNewtown, Albemarle County, VA

FINAL

RESPONSES TO REVIEW COMMENTS

JANUARY 2002

Prepared by:Engineering Division

U.S. Army Engineer District, Baltimore10 South Howard StreetBaltimore, MD 21201

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The EPA and the VADEQ REVIEW COMMENTSFor the

Revised Draft Focused Feasibility StudyGreenwood Chemical Company Superfund Site, OU-4

Newtown, Albermarle County, VA

General Comments

1. Site maps and contaminant plume maps presented in the document should include theOU-2 extraction well locations since their operation may affect the behavior (movement) of thesite groundwater.

Response: OU-2 extraction wells have been added to plume figures and are shown in theirentirety on Figure 2-4.

2. Typographical errors were identified on the following pages and should be corrected:

$ Page 5, paragraph 4, line 5;$ Page 6, paragraph 2, line 8;$ Page 7, paragraph 3, line 1.

Response: Typographical errors have been corrected.

3. It should be clearly stated that a portion of the manufacturing area is covered with cleansoil (spoil pile) from the construction of the groundwater treatment plant.

Response: The text has been edited to clarify that clean soil from the construction of thegroundwater treatment plant has been placed over portions of the former manufacturing area.

4. It is recommended that a separate set of remedial alternatives be presented for themanufacturing and drum disposal areas. The alternatives presented should be specific to eacharea.

Response: Concur. Remedial alternatives are now presented separately for each area.

5. The evaluation of remedial alternatives for OU-4 soil contamination should be addressedwithin the context of ongoing the groundwater response action. It should be clearly stated thatthe long term response action for groundwater will continue regardless of what cleanupalternative(s) are selected for the deep soil operable unit.

Response: Concur. This is now clearly stated in Section 5.0, last paragraph, last sentence.

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6. It should be indicated that the ultimate goal is the eventual remediation of OU-4 soil tomeet Preliminary Remediation Goals (PRGs). (It is understood that achieving this goal thoughmeans other than total removal of soil present significant technical problems).

Response: Concur. This goal is now indicated in Section 1.0.

7. Given the possibility that waste (i.e., contaminated soil) may remain in place and thatrestoration of groundwater remains uncertain, land use controls or more correctly, "institutionalcontrols" should be included as a key component of the remedial action alternatives for bothareas.

Response: Concur. Institutional controls have now been included in each remedial alternativefor both areas.

8. The USAGE will provide EPA the Final (100%) OU-4 FFS in electronic format (inaddition to the required number of paper copies).

Response: Concur.

Section 1.2

9. The Northern Warehouse is not mentioned in connection with either the ManufacturingArea or the Drum Disposal Area, nor is it mentioned in the remainder of the document. If thisarea was not considered in the document then this fact should be indicated and the reason forexcluding it from further consideration should be provided. The location of the NorthernWarehouse should also be shown on appropriate site maps.

Response: The explanation for not including the Northern Warehouse area is now indicated inSection 4.2.2. Reference Attachment 3, Northern Warehouse Sampling Results. Sampling wasconducted in 1997 to confirm the presence or absence of arsenic and acetone in the soil. Thehighest surface soil (0-2 feet) concentration for arsenic was 3.5 ppm. This was well below thesurface soil, risk-based PRG of 37 ppm. Overall, the highest level for arsenic was 55.6 ppm,collected from 4-6 feet below grade. This was well below the deep soils, groundwater-basedPRG of 400 ppm. All samples analyzed for acetone were below detection limits. Based on theseresults, the Northern Warehouse has been excluded from further consideration. The location ofthe Northern Warehouse is shown on Figure 1-3.

Section 2.3

10. It is recommended that more recent groundwater elevation measurements obtained in2000, prior to treatment plant operation, be used to construct a current water table contour map.(EPA has already provided USAGE with measurement data from spring-summer 2000).

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Response: Concur. Groundwater elevations recorded in February 2001 have been used to createa current water table contour map.

11. The statement regarding the eventual discharge of shallow (overburden) groundwater intoWest Stream should be qualified by indicating that the bedrock groundwater flow system is notnecessarily confined by this boundary and is controlled by the nature and extent of bedrockfracturing.

Response: Concur. The text has been revised as recommended.

Section 2.4

12. Please explain how the engineering, physical and biological properties of the vadose zonesoils were considered in the context of this feasibility study. Other than indicating that such datawas collected during the supplemental sampling event it is not clear how this informationfactored into the evaluation of remedial alternatives.

Response: The geotechnical data collected indicted that the soil consisted of high clay content.This data was used to screen out alternatives involving forced air movement through the vadosezone. The text in Section 2.4 now reflects this.

Section 3.0 (now Section 4.0)

13. It appears that Naphthalene acetic acid (NAA) was not considered a contaminant ofconcern (COC) at the Site. This appears to be an oversight and should be corrected. PRGsshould be developed for all COCs and presented in Table 4-6.

Response: NAA was used as a surrogate for the semi-volatile organic compounds in the RI andFFS. The data from for this chemical is now included in the analysis. Table 4-6 will be updatedaccordingly.

Table 3-1 (now Table 4-1)

14. It is not clear how the deep soil groundwater based PRGs were derived. Please provideall appropriate reference(s). It is assumed that the PRGs are based on the cleanup levelsdeveloped by EPA however, this needs to be clarified.

Response: The derivation of the groundwater cleanup goals is described in Section 3.0.However, the goals are used in Section 4.0 to assist in estimating the total volume ofcontaminated soil. The protection of groundwater goals were based on achieving the MCL orhealth-based limit (HBL) as listed in the Attachment D of the EPA's Soil Screening Level (SSL)User's Guide (EPA, 1996). The groundwater protection goals developed by EPA were not usedfor this task because the groundwater EPA protection goals are to be met at the facility boundary.

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The purpose of this task was to assist in estimating the total amount of soil removal that wouldbe required to protect on-site groundwater.

Section 3.2.2 (now Section 4.2.2)

15. A more detailed explanation should be provided as to the purpose of sampling in theNorthern Warehouse area and the interpretation of results. How was it determined, on the basisof the results, that this area would not be considered for possible future remediation?

Response: Reference USACE's response to comment # 9.

Section 3.2.3 (now Section 4.2.3)

16. The distinction (if any) between the standard SPLP procedure and the SPLP - Eastprocedure should be clarified and explained.

Response: The distinction between the standard SPLP procedure and SPLP-East procedure is inthe pH control during the determination of the analytes. The pH is adjusted to slightly below 7(in the acid side) for the SPLP-East procedure because the soils east of the Mississippi River aregenerally acidic, and the SPLP-East procedure simulates that condition.

Section 3.3 (now Section 4.3)

17. A more detailed explanation of how the contaminant plume maps for soil were developedand the relative size of plumes estimated should be provided. The description of the GMSprogram and its operation is confusing and requires a clearer explanation.

Response: The text has been revised to provide a more detailed explanation of the statisticalpackage used to create the area of soil contamination figures.

18. It should be noted that the estimate of soil volumes exceeding groundwater PRGs isoverly conservative given the assumption that the entire vertical thickness of the vadose zone(above the water table) is uniformly contaminated. It is likely that the actual soil volumes areconsiderably less, but this cannot be accurately verified based on the degree of deep soilsampling conducted.

Response: Concur. The text has been revised as recommended.

19. References to the OU-1 remedial activity as a "removal action" or "interim removalaction" are confusing and should be corrected to read "OU-1 remedial action."

Response: Concur: All references to OU-1 have been revised to "OU-1 remedial action".

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20. The reasons for not subtracting the volume of soil removed during the OU-1 RA from thevolumes estimated for the OU-4 contaminant plumes required further explanation. The volumeof material removed is well documented and therefore could be subtracted since contaminatedsoils were replaced with clean fill material.

Response: Concur. The soil volumes now only reflect contaminated soil quantities. The cleanfill material has been subtracted.

Section 4.1

21. The organic compound(s) used to evaluate the risk(s) associated with SVOC-TICs shouldbe identified. The 1993 groundwater modeling study performed by Halliburton NUS usednaphthalene acetic acid (NAA) as a surrogate compound for the SVOC-TICs. It is recommendedthat this same compound be used for this purpose.

Response: Since volatile and semi-volatile tentatively identified compounds (TICs) weresignificant components of the site contamination, surrogates having similar lexicologicalinformation were selected for use in the baseline risk assessment. Tetrahydrofuran was used as asurrogate for the volatile TICs and naphthalene acetic acid (NAA) was used as a surrogate for thesemi-volatile TICs for the purpose of calculating risk and hazard.

Section 4.1.3

22. It should be confirmed that the fill material placed in the former manufacturing area isindeed clean. Results of soil sampling conducted prior to construction of the treatment plant areavailable and will be provided for inclusion in the study. These results can be included inVolume II (Appendices).

Response: Results of soil sampling conducted prior to construction of the treatment plant werereviewed. The soil is clean in the organic portion and fairly clean in the inorganic (arsenic andcyanide) portion. The following is a brief summary of the sampling results for the inorganics:

• 4.1 mg/kg of arsenic in 1' BGS and 6.6 mg/kg of arsenic in 12' BGS - both are belowthe background value [estimated by USACE-Baltimore Toxicologist] of 18 mg/kg arsenic;and

• 0.4 mg/kg of cyanide in 1' BGS and 0.9 mg/kg in 12' BGS - both are above the backgroundvalue [estimated by USACE-Baltimore Toxicologist] of 0.12 mg/kg cyanide).

23. A typographical error was identified in this section. Specifically, "groundwater treatmentplant" is spelled incorrectly (page 15, second line).

Response: Concur. Text will be corrected.

Section 4.2

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24. It is not clear whether the risk-based cleanup goals contained in the EPA memorandumJanuary 18,2000 were considered. It is also not clear why a Dilution-Attenuation Factor (DAF)of 20 was selected. The basis for this selection should be provided.

Response: The EPA-develop goals were not used because they are applicable at the facilityboundary, not on-site, as described during the review meeting of 3 Oct 2001. The soil goalswere mainly developed to assist in estimating the total volume of on-site soil that would have tobe removed to achieve protection of the on-site groundwater. In addition, the DAF of 20 wasselected as recommended in EPA's SSL guidance. The DAF of 20 was selected because it isdescribed as protective of source areas up to 0.5 acres in size (EPA, 1996). The two source areasare less then 0.5 acres; therefore, the goals are conservative.

25. It is not clear how the modeled cleanup goals were derived. Please explain and provide areference(s) in the text.

Response: The soil concentration determined to be protective of an on-site groundwater wellwas determined by selecting the highest total soil concentration that did not result in the leachateconcentration exceeding the MCL or health-based limit (HBL) as listed in the Attachment D ofthe EPA's Soil Screening Level (SSL) User's Guide (EPA, 1996). The highest soilconcentration deemed protective was selected using the graphs in Attachment 5. Selecting pointsfrom the graph was used rather than the development of regression models, because of thepresence of multiple chemicals. Preliminary regression models (both linear and logarithmic)developed for all chemicals were not deemed useful even when accounting for differences in soiltype.

26. As a point of clarification, the groundwater risk-based goals developed by EPA are to bemet at the (downgradient) facility boundary.

Response: Concur. The text will be modified to reflect the point of applicability for the EPA-developed goals.

27. The narrative should indicate that the groundwater protection numbers developed by theUSAGE are for the purpose of defining the total extent of soil removed, if a full excavationalternative were selected.

Response: Concur. The text will be modified to reflect the point of applicability for the USAGE-developed goals.

28. All references to "dermal contact" should be changed to "direct contact."

Response: Concur. The text will be modified.

Section 4.3

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29. This section as presently written is unclear. Typically onsite and backgroundconcentration levels are compared statistically using the difference of the means test such as thet-test (for normal data) or a non-parametric test (e.g., Mann-Whitney) for all other distributions.It is also not clear what is meant by the term, "limiting factor."

Response: The text will be modified to clarify how the background concentrations were used.Depending on the cleanup scenario, the concentrations of naturally occurring metals can oftenlimit the size of an excavation. For example, the natural concentration of arsenic in soil often isthe cleanup goal rather than a risk-based goals, thus the background concentration is a "limitingfactor" on the cleanup (assuming that cleanup will not occur to concentration less thanbackground). However, in this case the surface soil concentration of metals in the surface soilwas less than the risk-based concentration. There was no need to compare the on-site andbackground concentrations of inorganic contaminants because the surface-soil cleanup goals arehigher than the maximum observed background value. The fact that the area is contaminated(i.e., above background) is assumed to been addressed in the RI.

30. It is recommended that the first sentence in this section be deleted since it is irrelevant tothe discussion.

Response: Please see discussion above.

Section 4.4

31. The Virginia Department of Environmental Quality (VDEQ) needs to confirm that allState and Local ARARs have been identified in the FFS.

Response: Chemical- location-, and action-specific ARARs were identified. ReferenceAttachment 6. The VADEQ provided USAGE a list of federal and state statues and regulationsthat potentially apply to the Greenwood Chemical site. The federal and state statutes andregulations that directly govern response activities are summarized in Tables 3-2 through 3-4,and were developed from VADEQ's list.

Section 4.5

32. It is recommended that more documentation be provided to better understand how thePRGs on Table 4-6 were developed. Note that the PRGs for the groundwater have beenprovided by EPA and should be considered in the calculation of the soil-to-groundwater cleanupgoals.

Response: Please see the previous responses to groundwater protection goals. The text will beaugmented in an effort to clarify the difference between the USACE-developed goals for the FFSand the EPA-derived goals for the remedial action system and the point at which each isapplicable.

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Table 4-5

33. This table listing TBCs should also include VDEQs Investigation Derived Wasteguidance document. VDEQ will provide a copy of the document entitled "Department ofEnvironmental Quality Waste Operations Policy for the Handling of Investigation DerivedWaste (IDW) dated June 28, 1995 and amended July 24,1996.

Response: The table will be modified in accordance with the comment.

Section 5.0

34. All remedial alternatives that leave contaminated soil in place, above limits forunrestricted use, should include institutional controls as an element of the remedy. The twotypes of institutional controls would apply to contaminated soil (shallow and deep) andgroundwater.

Response: Concur. Costs associated with institutional controls were included in each alternative.

35. Although discussed during the October 3, 2001 meeting, the concept of an upgradientground water infiltration gallery (trench) to assist in "flushing" contaminants from the deep soilshould not be included as a remedial alternative in this FFS.

Response: Concur. This concept was not evaluated.

36. It is recommended that remedial alternatives which do not pass the first two evaluationcriteria, overall protection of human health and the environment and compliance with ARARs,be screened out early in the process.

Response: Concur. Only the No Remedial Action Alternative was retained for baselinecomparison purposes.

37. It should be made clear that, if the site were closed as a capped landfill (i.e., waste left inplace) then it would meet ARARs as it is protective of human health and the environment.

Response: Concur. Reference Table 6-9. The capping alternatives were given an overall +rating factor for compliance with ARARs.

Section 5.2

38. Note that Maximum Concentration Limits (MCLs) may not achieve an accumulative risklevel than is protective for human health. Please refer to the EPA memorandum of January 18,2000 for more details.

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Response: Concur. Due to the presence of multiple chemicals in the groundwater, the MCLmay not be protective, as discussed in the initial portion of Section 4.0.

Section 5.4

39. It is recommended that in-situ bioremediation technologies including soil vaporextraction and/or bioventing be screened out in the initial screening of remedial alternatives.EPA has taken the position that soil properties such as low permeability and high clay contentmake the large-scale application of these technologies difficult.

Response: Concur. Reference Table 5.1. These technologies did not pass the initial screeningin the revised FFS.

40. Although results of the bioventing pilot study indicated significant reductions incontaminant concentrations in deep soil, EPA in unconvinced of the efficacy of this remedialtechnology given what are considered unpromising soil conditions.

Response: Concur.

41. A modified remedial alternative for the former drum disposal trench should be developedwhich includes "hot spot" removal of shallow contaminated soil above risk-based PRGs on theadjoining property. This is intended to address shallow soil contamination (both organic andinorganic) identified beyond the western property boundary and outside the original excavatedlimits of the former drum disposal trench.

Response: Concur. "Hot Spot" removal was assumed on approximately a 0.5-acre area on theadjoining property.

42. The "spot removal" of shallow soil contamination is considered a contingent remedybased on the evaluation of existing data and the collection of additional data. (It should be notedthat additional soil and groundwater sampling both on and off site to verify the nature and extentof contamination would be conducted during the design phase of this project). Institutionalcontrols relating to the first two evaluation criteria are to be applied in a restrictive manner onlywithin the site property.

Response: Concur. The "spot removal" alternative (referred to as permeable cap within thereport) inlcudes costs for on-site field analysis and laboratory analysis of soil. Costs associatedwith groundwater sampling were not included, as this is a separate operable unit (OU-2).

Section 6.1

43. It is recommended that capping alternatives should be given a "+" ranking factor forcompliance with ARARs.

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Response: Concur. The tables in Chapter 6 have been revised to reflect this.

44. The "+" and "0" ranking factors need to be revised in the detailed analysis of remedialalternatives as discussed during the 10/3/01 meeting. The "0" should be changed to "+."

Response: Concur. The tables in Chapter 6 have been revised to reflect this.

Section 6.2

45. It is recommended that two capping alternatives be considered, one employing animpermeable cap and the other, a permeable cap design. The capping option should beconsidered for both the manufacturing and drum disposal areas. The concept of one large cappedarea versus two smaller caps should also be considered. In the selection of appropriate caplocation and design, the EPA guidance for remedy evaluation and selection should be followed.

Response: Concur. Permeable and impermeable caps have been evaluated for both themanufacturing area and the drum disposal area. The concept of one large impermeable capcovering both areas has also been evaluated.

46. The impact of an impermeable cap design on the operation of the groundwater pump andsystem should be evaluated. Specifically, the effect of reduced recharge to the bedrock aquiferwould have on extraction well yields.

Response: Concur. According to the hydrologic soil map Albemarle County, Virginia, soils inthe area are known as Porters Stoney Loam. Porters Stoney Loam soils are classified as Type Bsoils. Infiltration rate for Type B soils ranges from 0.15 to 0.30 in/hr. Assuming animpermeable cap of 7 acres, the maximum reduction in recharge would be 2 in-acre/hr or 2f^/sec, for any given rainfall event. This will be discussed in Chapter 6 of the revised FFS.

47. The capping alternative should be considered for both near surface soil contaminatedwith inorganic compounds in addition to deep soil contaminated with organic compounds. (Acap design incorporating both permeable and impermeable elements should also be considered).

Response: Concur. Both permeable and impermeable caps have been evaluated for both themanufacturing area and the drum disposal area.

48. It should be indicated that regardless of the remedial alternative selected (with theexception of complete soil removal) that the OU-2 groundwater pump and treat system will bemodified, as necessary, to ensure containment of ground water contamination within theattainment area (site) since the system is presently intended for "hot spot" collection only.

Response: Concur. Text in Section 6.2 indicates that the OU-2 groundwater pump and treatsystem will be modified as necessary, regardless of the alternative selected.

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Section 6.3

49. It should be mentioned that cyanide contaminated soils are also present at the site.

Response: Concur. Section 6.3.1, sentence 2 now includes cyanide.

Section 6.3.2

50. It is more appropriate evaluate the effectiveness of each remedial alternative with respectto the attainment of cleanup goals (PRGs) as opposed to levels proposed in the Halliburton NUSfate and transport model (1993). The PRGs are considered to be more reflective of actual siteconditions.

Response: Concur. The text has been revised in Chapter 6 to evaluate effectiveness of thealternatives with respect to attainment of PRGs.

Section 6.3.7

51. In the detailed analysis of remedial alternatives, estimated O&M costs are presented.However, it is unclear whether these figures represent annual costs or costs over a 30-yearperiod. Please explain.

Response: The O&M costs associated with the impermeable cap option represent costs over a30-year period.

Table 6-4A (Detailed Analysis - Bioventing)

52. How was it determined that the bioventing alternative could achieve compliance withmodeled cleanup goals for naphthalene and VOCs? This statement requires further explanation.

Response: Bioventing has been screened out in this revised FFS.

53. It is noted that the analysis ranking factor "0" is used with respect to the technicalfeasibility of implementing this technology. Please explain what the "0" ranking factor means inthis case.

Response: The 0 indicated a neutral ranking factor. This revised FFS only used + or - rankingfactors to eliminate confusion.

Table 6-4B (Detailed Analysis - Bioventing and Excavation)

54. How was it determined that arsenic contaminated soil would "most likely" requiretreatment prior to disposal? (Please refer to remarks on page 3 of 7).

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Response: Arsenic is mixed with VOCs in many areas. Land disposal restrictions often requirepretreatment of VOCs prior to disposal in a landfill. The bioventing alternative is not included inthis revised FFS.

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HTRW Center of Expertise — Review CommentsPage 1 of 4Reviewer Name:Discipline09/12/2001Date:Project LocationDocument Name:Bave, EdwinComplianceNEWTOWN, VARevised Draft (Draft Final) - Focused Feasibility Study Report, Volume 1 -Report and Volume 2 - Attachments, Operable Unit No. 4 (OU-4), GreenwoodChemical Company Superfund Site, Newtown, Albemarle County, VA.

1. General: The ARARS section should be revisited and expanded. As ARARdiscussions are now presented, narrative criteria listed under alternativesand ARARs presented in table 4-5 do not coincide. Some specific examples areidentified below.

Response: The ARARs have been revised. The Chapter 6 tables have been revisedto coincide with Table 4-5.

2. Section 6.2.3 Alternative 3, entails the use of a "RCRA Subtitle C cap yet nodesign specific relevant and appropriate criteria are referenced or defined.If a true RCRA Subtitle C cap is envisioned, the appropriate design criterianeed to be articulated as an ARAR for that alternative.

Response: Because Greenwood Chemical site was basically a "dumping ground," andis not, nor will be, a true landfill, design criteria for RCRA Subtitle C & Dcaps are not ARARs, but are rather "to be considered." Reference the Section 6tables. Design criteria for Subtitle C facilities were selected for theimpermeable cap alternatives strictly because Subtitle C facilities employimpermeable caps. Design criteria for RCRA Subtitle D caps were selected for thepermeable cap alternatives because Subtitle D caps are typically permeable.

3. Sections 6.2.5 and 6.2.6. "or Cap Soils." Clarify the type/design criteriafor a cap/cover as an ARAR (i.e. subtitle C or subtitle D).

Response: See response to #2 comment.

4. For bioventing, soil vapor extraction, and combined alternatives, considerresidual or treatment by-products, leachate, condensation, etc may allrequire management of materials in tanks and containers which could triggervarious RCRA (40 CFR 261 - 268) applicability issues.

Response: Per EPA's request, these alternatives have beer, eliminated from thisrevised FFS.

5. Table 6-1, expand the table to reflect changes and detail issues such asthose listed above.

Response: Section 6 tables have been revised.

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Comment II:67865CX Project Review No.

HTRW Center of Expertise — Review CommentsPage 2 of 4Reviewer Name:Discipline09/12/2001Date:Project LocationDocument Name:Butler, SteveGeotechnicalNEWTOWN, VARevised Draft (Draft Final) - Focused Feasibility Study Report, Volume 1 -Report and Volume 2 - Attachments, Operable Unit No. 4 (OU-4), GreenwoodChemical Company Superfund Site, Newtown, Albemarle County, VA.

Page 9. Table 3-1. The RI data was collected 10+ years ago. Contaminantconcentrations may have changed due to the volatility of some of thecontaminants. This may affect the remedy decision process. Current conditionsshould be verified prior to selection of a remedy.

Response: Contaminant concentrations subsequent to the RI were verified duringtwo sampling events. One event was performed in 1997 and the second event wasperformed in the fall of 2000. The data from both sampling events has beenadded to the database as described in Section 4.0.

Page 15. Para 4.2. Using the SPLP to establish leaching of contaminants fromthe soils greater than 2 feet in depth is not likely to realistically modelfield conditions. Actual ground water monitoring data provides a more realisticestimate of how much contamination is leaching from the vadose zone soils.

Response: Comment noted.

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Comment il:67865CX Project Review No.

HTRW Center of Expertise — Review CommentsPage 3 of 4Reviewer Name:Discipline09/12/2001Date:Project LocationDocument Name:Hanson, StanleyCost EngineeringNEWTOWN, VARevised Draft (Draft Final) - Focused Feasibility Study Report, Volume 1 -Report and Volume 2 - Attachments, Operable Unit No. 4 (OU-4), GreenwoodChemical Company Superfund Site, Newtown, Albemarle County, VA.

Comment i 1: Attachment 7 - The estimate summary sheets are included however thedetail sheets are not. Include the estimate detail sheets in the attachment.

Response: The detail sheets will be included in the revised FFS.

Comment f 2: Attachment 7 - Note that the Escalation costs are not included inthe costs on the first 2 pages of the attachment.

Response: The detail sheets showing escalation costs will be included in therevised FFS.

Comment I 3: Attachment 7 - The second page of the attachment shows conflictingcosts for the Capital Costs of Alternative 6B.

Response: This will be corrected.

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Comment #1:67865CX Project Review No.

HTRW Center of Expertise — Review CommentsPage 4 of 4Reviewer Name:Discipline09/12/2001Date:Project LocationDocument Name:Tate, LauraProcess Engineer, HX-GNEWTOWN, VARevised Draft (Draft Final) - Focused Feasibility Study Report, Volume 1 -Report and Volume 2 - Attachments, Operable Unit No. 4 (OU-4), GreenwoodChemical Company Superfund Site, Newtown, Albemarle County, VA.

Comment i 1: alternative 1 The detailed analysis of no action shows no costin the bottom line while in the long -term effectiveness and permanence analysismonitoring and a 5-year review are assumed. When there are legitimaterequirements for site restoration, the no action alternative is neither cheapnor free. The engineering and legal costs of justification of no action areadditional costs. Treatment of the contaminants in the groundwater 00 wouldalso be costly.

Response: The RACER estimate for the no action alternative has been revised toinclude costs for potential legal fees and institutional controls. Because thisFFS only addresses OU-4 (deep soil) contamination, costs for treatment ofcontaminants in the groundwater were not included.

Comment # 2: alternative 2 The cost of this alternative could be reducedsubstantially by better definition of the quantities and of the pretreatmentrequirements.

Response: Concur. The volume estimate provided in Section 4.0 has been revisedto reflect only contaminated soil. Clean fill material placed during OU-1remedial activities, as well as stockpiled soil from OU-2, groundwaterextraction well construction, has been subtracted out.

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Comments from HTRW-HT (M. Ponnapalli)

Greenwood Chemical Superfund SiteNewtown, Albemarle County, Virginia

OU-4, Revised Draft Focused Feasibility Study Report

1. Executive Summary. The second paragraph refers to 15 site contaminants of concern (CoC)at Greenwood Chemical. However, all other text (for example the first paragraph in Section 3.0),states that 18 CoC were identified at the site. Which is correct? Clarify and correct.

Response: The text was clarified and the number of COCs is consistent.

2. Executive Summary. In the last sentence in the second paragraph, "Of the site 15contaminants of concern, 9 are present in OU-4 soils above action levels," are action levels thesame as "preliminary remediation goals" which are mentioned far more often in subsequent text?Also, is nine still the correct number of CoC above action levels given that there are probably 18CoCs, not 15?

Response: The text of the Executive Summary was clarified.

3. Section 1.2 - Site Description. The second sentence in the first paragraph in this sectionrefers to Figure 1-2, the Site Location Map, which is missing. Please include it.

Response: The site location map will be included.

4. Table 3-1 - Contaminants of Concern and Preliminary Remediation Goals. Why are thereno maximum concentration values listed for xylene in the drum disposal and manufacturingareas? Please correct.

Response: The table was corrected after additional data on xylene was obtained from thelaboratory.

5. Section 4.2 - Groundwater Protection-Based Goals. The last sentence in the secondparagraph in this section refers to Figure 4-1. Is that the Figure after Table 4-6? If so, pleaselabel it with its Figure number.


6. Table 4-1 - Summary of Preliminary Remediation Goals for Protection of Off-SiteGroundwater. Tetrohydrofuran has a large difference/change between the modeledgroundwater protection goal (97,269 mg/kg) and the leachate-derived groundwater protectiongoal (0.4 mg/kg). Please check your calculations/data for arriving at each number as this couldmake a large difference in the risk assessment and areas to be remediated.

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Response: Text was added to the report to show that one detection of tetrahydrofuran in a SPLPsample drove the generation of this goal. The boring location from which this sample wascollected had no other detection of tetrahydrofuran in two other samples. The leachate-derivedgroundwater protection goal is likely too low.

7. Table 4-1 - Summary of Preliminary Remediation Goals for Protection of Off-SiteGroundwater. Xylene is not listed among the CoC in this table. Please include it.

Response: The tabled was corrected after additional data on xylene was obtained from thelaboratory.

8. Section 6.1 - Evaluation Criteria. Page 32 is missing. Please include it.


9. Table 6-2 - Detailed Analysis - Excavation and Disposal - Alternative 2. Pages 4 and 7are missing. Please include them.


10. Table 6-3 - Detailed Analysis - Capping all Impacted Soils - Alternative 3. Pages 3 and7 are missing. Please include them.


11. Table 6-4A - Detailed Analysis - Biovent Organics - Alternative 4A. Pages 3 and 4 aremissing. Please include them.


12. Table 6-5C - Detailed Analysis - Soil Vapor Extraction and Cap Inorganics - AlternativeSC. In the "Reduction of Toxicity, Mobility and Volume Through Treatment" criteria, why arethe "Amount of hazardous material destroyed or treated", "Reduction in toxicity, mobility, orvolume" and "Irreversibility of the treatment" rows rated "+" while the same rows are rated "0"for Biovent Organics and Cap Inorganics (Alternative 4C), for the same results? After all,neither Alternative 4C or 5C will treat inorganics. Defend your position.

Response: The table has been revised to be more consistent.

13. Table 6-6C - Detailed Analysis - Bioventing and Soil Vapor Extraction and CapInorganics - Alternative 6C. In the "Reduction of Toxicity, Mobility and Volume ThroughTreatment" criteria, why are the "Amount of hazardous material destroyed or treated","Reduction in toxicity, mobility, or volume" and "Irreversibility of the treatment" rows rated "+"while the same rows are rated "0" for Biovent Organics and Cap Inorganics (Alternative 4C), for

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the same results? After all, neither Alternative 4C or 6C will treat inorganics. Defend yourposition.

Response: This table has been revised to be more consistent.

14. Table 6-7 - Comparative Analysis of Alternatives. Should alternative 5 A, (soil vaporextraction), really be given a "0" sign in the "Reduction of Toxicity, Mobility and VolumeThrough Treatment"" column, given that Table 6-5A (p.3), gives a "+" rating for the samecriteria? Clarify and correct if necessary.


15. Table 6-7 - Comparative Analysis of Alternatives. Should alternative 6C, (bioventing,soil vapor extraction and cap inorganics), really be given a "+" sign in the "Reduction ofToxicity, Mobility and Volume Through Treatment"" column, given that inorganics will not betreated? Clarify and correct if necessary.


16. Section 6.0 - Detailed Analysis of Alternatives. Section 6.0 should have arecommendation paragraph at the end. Which of the 12 alternatives, evaluated in detail inSection 6.0, is the recommended alternative?

Response: Per the EPA's request, we are not recommending an alternative. Based upon thefindings in the FFS, the EPA will select an alternative.

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Comments from HTRW-HT (L. Finley)

SUBJECT: Review Comments of OU-4 Focused Feasibility Study Report, GreenwoodChemical Company Superfund Site, Newtown, VA

1. Intro 1.1 - 1. To confirm whether the arsenic and cyanide contaminated soils, or the deepsoils pose...

Response: The text was clarified.

2. Site Description 1.2 - OU-1 is 937 square what? Area? Is it 937 or 935? On page 3 it isdescribed as the 935 Square Area.

Response: The area was called the "East Drum Area or the 935 Square Area" in past reports.This name does not reflect the square footage of the area.

3. Site History 1.3 - Third sentence of second paragraph seems like it is not complete. "A varietyof chemical products.. .have been manufactured...? Here? On the premises?


4. Site History 1.3- Third paragraph, third to last sentence,.. .elongate material should probablyread elongated.


5. Site Geology 2.2 - There is a very factual discussion of the site geology but the section neverdiscusses the significance of the site geology, e.g. what does this mean, how doesit relate to the contaminants present?

Response: Due to the high clay content present at the site, approximately 30% clay by weight,technologies involving air movement through the vadose zone were screened out. Thesetechnologies included soil vapor extraction and bioventing. The text in Section 2.2 has beenrevised to reflect this.

6. Soil and Vadose 2.4 - In the second paragraph it states that auger refusal was met as thecontent of soil became more silty sand rather than silt and clay. It seems that claywould have presented more refusal than silty sand.

Response: The assumption that clay would present auger refusal prior to a silty sand is incorrect.

7. Extent of Contamination - 1,2-Dichloroethane is misspelled.

Response: Word has been corrected.

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8. Evaluation... 3.1 - Second paragraph, middle of paragraph, should read into rather than in to.

Response: Text has been corrected.

9. Sampling in Northern...3.2.2 - Sixteen soil samples from seven bore holes... Were they atdifferent depths, a little more explanation would clarify.

Response: This section has been revised to include a discussion of sample depths.

10. Page 7, second sentence - ...a COCs' potential (add apostrophe).


11. Page 7, Second paragraph, third sentence - Surface soil risk-based PRO is one thing, thereshould not be a comma after surface soil.


12. Table 3-2, page 11 - Were soil volumes corrected for the clean and removed soil? Thefootnote says the volumes were not, but some believe they were adjusted. Needto verify and correct, if necessary.

Response: The soil volumes represent contaminated soil. The clean soil has been subtracted out.

13. Preliminary Remediation Goals 4.0 - The sentence, "The earlier PRGs are modified (weremodified, will be modified).. .becomes (became)..." verbs should agree in tense.

Response: Text has been revised.

14. Preliminary Remediation Goals 4.0 - Second paragraph, .. .under federal or stateenvironmental laws...add the word laws.


15. Baseline Eco... 4.1.2 - Second sentence, ...COCs could not be determined due to the lack of.. .(rather than unavailability).


16. Baseline Eco, 4.1.2 - Second paragraph, .. .contaminated soil... add the word soil.


17. Groundwater Protection-Based Goals 4.2 - In paragraph one states that the fate and transportmodel was acceptable but lacked a sensitivity analysis which then created "great uncertainty".How is this acceptable?

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18. Groundwater Protection-Based Goals 4.2 - Paragraph four states that the regression modelswere not deemed useful, why?

Response: The regression model were not useful because the r2 values for the models were lessthan 0.80, which was used as the acceptable criteria. Transformation of the data were not usefulincreasing the degree of correlation.

19. Background-Based Goals - Last sentence of first paragraph states that the shallow surface-soil samples were representative of entire soil profile for deep and shallow soils. However inthe Site Geology Section 2.2, it goes into detail about the differences in the soils? These twoviews seem to contradict each other?!

Response: The data was reviewed by the project geologist and the soil types do not differsignificantly from the surface to the subsurface. Any difference that were discussed in thegeology section were directed toward the selection of a remedial alternative, not to indicate thatthe parent material (and thus the chemical composition) of the surface and subsurface soil wasdifferent.

20. Scope of Federal ARARs 4.4.1 - Page 19, top paragraph, last sentence, "Only the substantiveelements".. .what does the term substantive mean in this context?

Response: EPA interprets CERCLA Section 121(e) broadly to cover all administrativeprovisions from other laws, such as recordkeeping, consultation, and reporting requirements. Inother words, administrative requirements do not apply to on-site response actions. Only thesubstantive elements of other laws affect on-site responses. Examples of "substantive elements"include concentration limits for chemical emissions or discharges and specifications for thedesign and operation of remediation equipment.

21. ID of Potential ARARs 4.4.4 - First bullet add the word ofafter list.

Response: Do not concur. The text of the section was modified so that the comment is no longerapplicable.

22. Summary 4.4 - Second sentence, add the word of after protective.


23. Table 4-1 - For tetrahydrofuran, I noted a very big difference between the modeledgroundwater protection goal and the leachate-derived groundwater protection goal. Any reasonfor this?

Response: Text was added to the report to show that one detection of tetrahydrofuran in a SPLPsample drove the generation of this goal. The boring location from which this sample was

collected had no other detection of tetrahydrofuran in two other samples. The leachate-derivedgroundwater protection goal is likely too low.

24. Table 4-4 - Under Standard for fugitive dust/emissions there are no federal standards listedfor air regulations or OSHA that must be complied with?

Response: The table was clarified and fugitive dust/emissions were considered under the action-specific ARARs. OSHA regulations are not an ARAR.

25. Table 4-6 - Asterisk sentence at bottom of Table should include the word the beforegroundwater.

Response: The table was removed from the report.

26. ID and Screening of Technologies 5.1 Intro - FFS addresses the COCs in the "deep" soils?What is definition of "deep"?

Response: The "deep soils" are those soils that were outside the scope of the previous removalactions.

27. Section 5.4 - Sentence before bullets on page 29 needs colony.


28. Evaluation Criteria 6.1 - Page 31, sixth paragraph, first sentence,... in this report areprogramming level and order of magnitude estimates. Add the word and.


29. Alternative 3.. .6.2.3 - Why remove clean soil? It seems that leaving it in place would beextra protection and it would not cost anything.

Response: The clean soil was removed to get to the underlying contaminated soil.

30. Alternative 5...6.2.5 - Second paragraph should begin with The not This.

Response: Section 6 has been revised.

31. Overall Protection of Human Health 6.3.1 - Beginning sentence states all alternativesprovide adequate protection. Is this so? It seems that some did not address the mass transport ofthe COCs very well and that two alternatives stood out. Second sentence should read "Risk fromdirect contact". This initial paragraph may need to be re-written.

Response: The text was clarified. All alternatives do not provide adequate protection of humanhealth.

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32. Reduction of Toxicity...6.3.4 - There is no discussion of alternative 6 and in particular 6Bwhich was a preferred alternative. Discussion should include 6 as well as the others.

Response: Section 6 has been revised to include a discussion of all the alternatives.

33. Cost, 6.3.7 - Each cost of the alternatives is listed, it would be easier to read/understand ifTable 5-2 was reproduced here and cost of alternative included in Table to compare visually.Also noted was that the cost was carried out to dollar amount. The cost could probably berounded for the comparison here.

Response: A cost table is now included. The costs are now rounded for easy comparison.

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Comments from HTRW-HI (R. Miller)OU-4 Focused Feasibility Study Report,

Greenwood Chemical Company,Newton, Albemarle county, Virginia

Review Comments

1. Page 2, section 1.3,2nd paragraph, 3rd sentence - Recommend deleting the semicolonbetween naphthalene;acetic acid.

Response: The text was modified.

2. Page 5, section 2.4, paragraph 3 - Recommend including the dates of the supplementalsampling program.

Response: The text was modified to clarify the sampling dates.

3. Figures - Recommend including the labels Figure 1-1 and Figure 1-2 on the first twofigures.

Response: The text was modified and all figures will have numbers.

4. Figure 1-3 - Recommend increasing the font size.

Response: The font size has been increased.

5. Table 5-1 - Recommend combining the two notes in one sentence.

Response: The notes have been combined.

6. Tables 6-1 through 6-7 - Recommend clarifying the meaning of the rating factors (+, -&0).

Response: The text was modified and the rating factors were redefined.

7. Attachment 3, period: From 11/14/2000 thru 11/14/2000, page 13 of 14, Site AOO-5,11/15/2000 - Recommend changing <1 to 1 U to be consistent with other non-detects inthe table.


8. Attachments, Attachment 6, page 8, general comment - Recommend moving the title(Al_Result) to the page to which it pertains.

Response: The text was modified.

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CENAB-EN-GG 10 September 2001

Review Comments from GeoTech (T. Bergling)OU-4 Focused Feasibility Study Report

Greenwood Chemical Company Superfund SiteNewtown, Albemarle County, Virginia

Dated August 2001

1. General: Report appears to have been put together in a rush. Figures are not properlyreferenced in the text or are missing in the document all together. Two pages (6 and 29)were missing from the document.


2. Development of Alternatives in Section 6: The presentation of alternatives is a bitconfusing. Suggest this be reformulated as 4A and 4B, 5A and 5B, 6A and 6B, with forexample 4A being bioventing with hot spot removal and 4B being bioventing withcapping. Similarly, 5A would be SVE with hot spot removal and 5B would be SVE withcapping; 6A would be the bioventing & SVE combination with hot spot removal and 6Bwould be the bioventing & SVE combination with capping.

Response: The remedial alternatives were re-grouped for the drum disposal area and themain manufacturing area. SVE was removed from consideration after discussions withEPA and evaluation of the pilot study report.

3. Development of Alternative 2 in Section 6: The text leaves the impression thatalternative 2 is superior to all of the other alternatives until the cost is discussed, and then,the cost is just presented in a matter of fact way as being $94,484,915. In the nextsentence it is mentioned that alternatives 3, 4 5 and 6 are superior to alternative 2, due tothe high cost of '2'. According to the text, development of the cost estimate foralternative 2 did not include the volume of non contaminated soils lying above thevolume of contaminated soils. Nor were excavation issues such as sloping and benchingof excavations (which increase the volume of materials that must be removed to get to thecontaminated materials) addressed. It also does not appear that the volume of placedspoils above the natural grade was addressed in the cost of alternative 2. It isrecommended that Alternative 2 be screened out as being much too expensive before thisis presented as a serious option.

Response: The alternatives have been revised. Excavation has been retained in therevised FFS per the request of EPA Region III. It is now broken into the following twoareas: the Drum Disposal Area and the Manufacturing Area. The excavation volume inRACER included both non-contaminated soil and contaminated soil. It was assumed inRACER that the non-contaminated soil would be used for backfill. Based on the totalvolume to be excavated, a 1: 0.75 (V:H) benching of the excavation was assumed in RACER.

It is also recommended that all costs be presented in round numbers with no more than 3or 4 significant figures. Presenting the costs for the various alternatives down to thedollar is a bit of a stretch that implies an accuracy far beyond that achievable at this stage.

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CENAB-EN-GG 10 September 2001

Costs should also be appropriately qualified. Unknowns and items that can not beaccurately estimated at this time (or ever) should be highlighted.

Response: Concur. The costs have been rounded in the revised FFS.

4. Development and Screening of Alternatives, Section 5: This section seems toconsist only of Table 5-2, which makes no sense. There doesn't seem to be anydevelopment or screening of any ideas in this section.

Response: Section 5 has been revised. Several technologies were screened out primarilybecause the soil properties at the site, such as low permeability and high clay content,make the large-scale application of these technologies difficult.

5. Method of Background Determination, Section 4.3: Collection of samples for thebackground determination from only the top foot may or may not be representative ofmetals concentrations throughout the soil profile, and may lead to a low bias in thebackground levels. Metals are commonly leached from the upper soil horizons with theaid of organic activity in the topsoil layers. Rather than taking 10 samples in the top 1foot, it would have been preferable to take the samples throughout the soil profile at twoor three upgradient locations, using USDA soil maps and geologic maps to guide thesample collection points.

Response: The project geologist reviewed the boring log data. The soil types andcharacteristics do not differ significantly from the surface to the subsurface. Anydifference that were discussed in the geology section were directed toward the selectionof a remedial alternative, not to indicate that the parent material (and thus the chemicalcomposition) of the surface and subsurface soil was different.

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Documents

OU4 FOCUCED FEASIBILITY STUDY (FS) REPORT