SDMS DocID 2072478

May 3,2002 .

Mr. Bhupi D. KhonaRemedial Project ManagerSuperfund Remedial BranchU.S. Environmental Protection Agency Region IIIHazardous Site Cleanup Division 3HW221650 Arch StreetPhiladelphia, Pennsylvania 19103-2029

Dear Bhupi:

Subject: Responses for Agency Comments on Phase 2 TechnicalMemorandum and Proposed Phase 3 Investigation ScopeRemedial Investigation/Feasibility StudyBreslube Superfund SiteCEC Project 98838.0602

Civil & Environmental Consultants, Inc. (CEC) and the Breslube-Penn JointSteering Committee (Committee) received comments from the United StatesEnvironmental Protection Agency (EPA) and the Pennsylvania Department ofEnvironmental Protection (DEP) on the Phase 2 Technical Memorandum andProposed Phase 3 Investigation Scope on April 22, 2002. We have had anopportunity to review these comments, and appreciate the careful review that wasprovided by agency representatives.

The purpose of this letter is to provide written responses for those comments.Agency comments on the Phase 2 Technical Memorandum are included below:

1.0 RESPONSES TO AGENCY COMMENTS

1.1 BHUPI KHONA COMMENTS

Bullet 1: Groundwater sample results highlighted in the attached table seem tohave a high degree of variability, please explain. Also it appears that the resultsfrom Phase 1 and Phase 2 show a significant amount of variability. The detection

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limits for the same compounds listed are different for some duplicate samplesand also for some results from Phase 1 and Phase 2.

Committee Response: The variability between the Phase 1 and Phase 2 groundwateranalytical results may be due to a number of factors including but not limited to;climatic changes, infiltration effects, and variation in well purging methods. It is notpossible, with only two sets of groundwater analytical data, to identify trends or thecause(s) for variation in the analytical results. Additional groundwater samples will becollected during the Phase 3 investigation and will provide another point ofcomparison. The differences noted in detection limits may be attributable to thedilutions associated with that specific sample and matrix interferences. Evenconsidering the sampling variability, it is CEC's opinion that the groundwater dataprovide meaningful information on groundwater quality, and that the conclusionsregarding groundwater quality that are reached from evaluation of the data are notimpacted by the sample variability.

Bullet 2: The validated data submitted in February 2002, does not havesummary of validation findings with some explanation of data usability in linewith the Data Quality Objectives (DQOs) set forth for this project.

Committee Response: Environmental Data Services (EDS) has provided CEC with a"Data Assessment Narrative" for each sample delivery group collected and analyzedduring the Phase 1 and Phase 2 investigation. These narratives include summaries ofdata quality issues (if any) as well as an explanation for the application of datavalidation qualifiers to individual analytical results. The Data Assessment Narrativesare contained in EDS's Data Validation Reports. Copies of the Data Validation Reportswill be included in the Remedial Investigation Report to be submitted to EPA at thecompletion of the Remedial Investigation (Rl).

Bullet 3: The soil sample results do have variability but that can be attributed tothe difficulties with solid matrix.

Committee Response: CEC and the Breslube-Penn Joint Steering Committee(Committee) agree with this comment.

Bullet 4: The proposal of the Phase 3 investigation should include additionalgeophysical survey methods such as gro.und penetrating radar to supplement the

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magnetic survey proposed. This will enhance the survey resulting in reducedchances of inherent errors associated with this kind of techniques.

Committee Response: The Committee agrees that Ground Penetrating Radar (GPR) willbe used concurrently with the EM-31 resistivity survey during the Phase 3 investigation.The Group believes that there are some limitations associated with the use of thegeophysical surveys due to the nature of the site (concrete, rebar, etc.). The results ofboth surveys will be compared and used to identify magnetic anomalies at the Site thatwarrant further investigation during the Phase 3 Test Pit program.

Bullet 5: The goal of Phase 3 is to finalize the data collection process and closethe data gaps. Keeping that in mind EPA feels that twp additional well clustersare needed-on the other side of the creek in the direction of groundwater flow,preferably from the buried lagoon area. This is necessary to determine thepotential threat, if any, due to the Site related contamination migration, if any, onthe other side of the creek.

Committee Response: To address EPA and DEP concerns about the potential forgroundwater migration beneath Montour Run, the Committee agrees to install threeadditional monitoring wells. The Committee agrees to install one additional wellcluster (one shallow and one bedrock well) on the other side of Montour Run, in thedirection of groundwater flow from the buried lagoon area. The location for thisadditional well cluster (MW-16 and MW-16B) is shown on Figure 1. In response to acomments from Herminio Conception and Dawna Yawnacci (DEP), the Committee alsoagrees to install a bedrock monitoring well at the proposed MW-13 shallow welllocation, thereby creating a second well cluster downgradient of the buried lagoonarea. The Committee believes that installation .of these three additional wells will besufficient to investigate the quality of groundwater discharging from the lagoon area toand/or beneath Montour Run.

1.2 HERMINIO CONCEPTION COMMENTS

Comment 1. The cross sections in figures 5 and 6 indicates zones of lithologiccontrasts that could be correlated between boring logs, particularly zones ofcoarse and fine grained materials that could encourage preferential pathway forcontaminants and groundwater flow. For example comparison of the wells MW-6and 6B at the east of the site, where the contaminant seems to move vertically

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while in MW-1 and IB at the west the contaminant seems to move laterally,distinct lithology could serve as localized preferential pathways for contaminants.What likely happens is that zones of coarse-grained materials expedite themovement of groundwater and any associate contaminants down gradient to azone of fine-grained material, where they then move either vertically or laterallythrough less permeable material to the next coarse grained zone, and so on. • Thesoils and the vadose zone at Breslube represent one of the most important mediafor contaminant transport and must be fully characterized. Properties of surfacesoils and the vadose zone influence the type and rate of contaminant movementto the subsurface and subsequently to the water table. Contaminants that canmove through the surface soil and into the vadose zone may move directly to thewater table or they may partially or fully retained within the vadose zone to act ascontinual sources of groundwater contamination. Comparison of the soilencountered during the construction of wells and comparison of the estimatedhydraulic conductivities should be performed to determine if a preferentialpathway exists in this area. Use the available data to assess the presence ofpreferential pathways at the site.

Committee Response: The Committee agrees that many factors influence the fate andtransport in the subsurface, especially in.zones with higher permeabilities. Propertiesof surface and subsurface soils, variation in aquifer permeabilities, and Sitehydrogeology will be considered when evaluating the migration pathways. The resultsof these evaluations will be presented in the Rl Report.

Comment 2. The report states on page 4 that for the eastern portion of the site,the groundwater flow direction appears to be to the east, however figure 8 of thereport shows the groundwater flow direction to the southeast. The groundwaterflow map from February 19, 2001 included in the document TechnicalMemorandum - Proposed Phase 2 Investigation Scope, March 16, 2001 shows thegroundwater direction to the east. Please provide interpretation and discussionon both groundwater flow maps. This information is important to choose the bestlocation for the monitoring well at the east portion of the site.

Committee Response: It is CEC's opinion that the differences in groundwater flowshown on the maps for February 27, 2001 and August 14, 2001 are negligible.Shallow groundwater flow is to the east-southeast toward Montour Run. Subtledifferences in the flow lines presented in the February 2001 map and the August 2001

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map are due to the addition of another shallow well (MW-12) in the eastern portion ofthe site and the loss of the stream gauge monitoring point for Montour Run. In August2001, the surface water elevation measurement for Montour Run was obtained bytransit measurement from the water surface at a point further downstream than the'February 2001 stream gauge measurement. Based on the water level elevation datafrom MW-6, MW-12 and Montour Run, the contour lines in the August 2001 map werecurved slightly more toward the southeast than the lines shown on the February 2001map. However, since contouring is always somewhat subjective, the groundwater flowmaps for the two dates can be considered to be virtually identical. The Committee andCEC believe that monitoring wells are appropriately located.

Comment 3. Discuss the relationship between Montour Run and the sitegroundwater.

Committee Response: Please see the response to Comment 2 regarding therelationship between Montour Run and the site groundwater. A more detaileddiscussion of the relationship between Montour Run and site groundwater will be in theRl Report.

Comment 4. The analytical'results for the wells IB, 5B and 6B shows that thecontamination at the site is migrating to the bedrock. A cluster of wells, oneshallow and a deep well, must be installed for the phase III at the .locationproposed for well (MW-13) to provide data on groundwater quality down-gradientfrom the site for both shallow and deep aquifers.

Committee Response: Please see the response to Bhupi Khona Bullet 5. As noted inthis section, the Committee will install one bedrock well at the proposed MW-13shallow well location (creating a shallow and deep well pair). The Committee hasagreed to install an additional well cluster (one shallow well and one bedrock well)across the creek from MW-13.

1.3 NANCY RIOS-JAFALLA COMMENTS

Comment 1. Figure 9. Could not verify TEF calculations on Figure 9 or Table 3.

Committee Response: The mathematical equations and dioxin/furan concentrationdata used to calculate TEFs, summarized on Table 3 and graphically presented on

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Figure 9, will be provided to EPA as an attachment to the revised Phase 2 TechnicalMemorandum.

Comment 2. Figure 10. Background determination for arsenic should only bedone qualitatively at this stage. A quantitative assessment is required if COPCsare eliminated based on background level comparison with onsite levels. Thisoccurs at the end of the risk assessment. Please note Jennifer's comments on4/9/01 and 6/7/01. .

Committee Response: The Committee agrees with this comment. Further screeningand statistical analyses of site data versus background data will be conducted duringthe risk assessment.

Comment 3. Figure 11. It is not clear why surface soil concentrations for leadare used to make a determination of groundwater quality. The action level forlead and the soil-to-groundwater guidance should be used.

Committee Response: The statement "CEC's review of the monitoring well groundwatersamples presented in Appendix E identified that concentrations of lead generally werebelow or close to drinking water standards'(15 microgram per liter [ug/L//' on page 5of the Phase 2 Technical Memorandum was presented as an observation. Althoughlead concentrations in surface soils range from 16.7 mg/kg to 1,290 mg/kg, lead doesnot appear'to be leaching into groundwater at concentrations in excess of drinkingwater standards. Lead concentrations in surface soils were not intended to be screenedagainst the drinking water standard for lead.

Comment 4. Figure 12. The PCBs levels were compared to TSCA action levels(50 ppm). Note that the RBC for PCBs should be used for screening, not theTSCA levels.

Committee Response: PCB concentrations in surface soils were not screened againstthe TSCA action level of 50 ppm (50 mg/kg) for PCBs. Note 1 on Figure 12 states thatthe EPA Region III RBC for PCBs is 2.9 mg/kg. Surface soil data will be screenedagainst the EPA Region III RBC for PCBs during the risk assessment. The TSCA actionlevel was presented for comparison purposes only.

Comment 5. Figure 13. Again background interpretation of subsurface soil is

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premature at this stage. Also, the soil-to-groundwater RBCs should be used, notthe surface soil ingestion RBCs.

Committee Response: The comparison of arsenic concentrations in subsurface soil tobackground soils was intended to be qualitative. The EPA Region III RBC for industrialsoil, posted on Figure 13 (3.8 mg/kg), will be revised to reference the EPA Region IIIsoil to groundwater RBC (0.026 mg/kg).

Comment 6. Figure 14. Use the soil-to-groundwater RBC, not the soil ingestionRBC or action level.

Committee Response: The EPA Region III RBC tables do not provide RBCs for lead,therefore screening criteria for lead in soils were not presented on Figure 14.

Comment 7. Figure 15. Again, the TSCA regulations are used for screeningsubsurface soil. See comment above.

Committee Response: .The Toxic Substances Control Act (TSCA) governs themanufacture, use, and disposal of PCBs. PCB wastes generally are regulated fordisposal under TSCA at concentrations of 50 ppm or greater. According to the disposalamendments, the term PCB waste may also be applied to environmental mediacontaining PCBs such as soil, gravel or sediments. The definition of PCB waste doesnot include a reference to soil depth. As stated in the response to Comment 4, theTSCA action level was presented for comparison only.

Comment 8. Figure 16-25. Use the RBCs for groundwater screening, not theMCLs.

Committee Response: Groundwater data on Figures 16 through 25 were not screenedagainst Federal Maximum Contaminant Levels (MCLs). MCLs were included on Figures16 through 25 for comparison and because these concentrations are acceptable fordistribution of drinking water. During the risk assessment, groundwater data will bescreened against EPA Region III RBCs.

Comment 9. Surface Water and Sediment screening. It is not clear if thescreening included human health receptors (See Appendix E).Committee Response'. Screening criteria were not included in the tables provided in

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Appendix E. Surface water and sediment data will be screened against human healthcriteria in the human health risk assessment and against ecological criteria in theScreening Level Ecological Risk Assessment (SLERA).

Comment 10. Industrial RBCs were used in several places. Jennifer's previouscomments (4/97,01 and 6/7/01) requested that justification be provided forusing industrial RBCs. No justification was provided.

Committee Response: The property is zoned industrial and previous land use has beenindustrial. Remedial alternatives for the property may include instituting a deedrestriction that limits future use of the property as industrial/commercial. Therefore,the Committee concluded that industrial use RBCs are appropriate for screening thesoil data considering the previous and realistic proposed future use of the property.

Comment 11. It is not clear that soilsiwill be (or have been) sampled for SVOCsper Jennifer's comments on 4/9/01 and 6/7/01.

Committee Response: Five surface soil samples and forty-three subsurface soilssamples collected during the Phase 2 investigation were analyzed for semivolatileorganic compounds (SVOCs). The analytical results were included in Appendix E.Because there were only a few locations where SVOCs were identified at concentrationsabove RBCs, these data were not graphically presented.

1.4 BRUCE PLUTA COMMENTS

Soil Background Locations. The map provided from the revised Phase 1 report(Figure 2) has been examined to evaluate the appropriateness of the locations.BTAG contends that locations 4, 7 and 8 are not suitable for determiningbackground soil concentrations. Location 4 is downgradient of surface waterrunoff and groundwater flow, as well as in the vicinity of highly contaminatedproduct. Locations 7 and 8 are downgradient of the site in close proximity toMontour Run. Given the constrained nature of this reach of the creek, theselocations have a high probability of being inundated in high water events. Thus,contaminants bound to suspended sediments deposited in these areas duringfloods are likely to have biased soil concentrations. BTAG recommends use ofdata from the remaining locations (i.e., ,1, 2, 3, 5, 6, 9 and 10) for comparison tobackground.

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Committee Response: The soil background locations were selected prior to samplingby the Committee's consultant, CEC, after consulting with EPA representatives at thesite. CEC agrees that background sampling location 4 will be discounted from thebackground data set because it is downgradient from the site. Although some of theremaining locations could potentially be inundated during extremely high water, bothEPA and CEC concluded that the sampling locations are acceptable and appropriate forestablishing background conditions.

Soil PCDD/PCDF/PCB Interpretation. These three classes of compounds causesome toxic effects by a similar mechanism of action. While human health hasestablished criteria to assess PCBs separately from PCDD/PCDF, ecologicalevaluation of these compounds needs to consider both distinct and cumulativeeffects. One approach would be to take add.itional samples for PCB congeneranalyses to compute an overall TEQ. Alternatively, BTAG recommends combiningthe Aroclor PCB and PCDD/PCDF TEQ HQs for similar assessment endpoints inthe screening level ecological risk assessment (SLERA) to derive at a cumulativeHazard Index (HI). This approach will permit evaluation of each contaminantclass separately via their individual HQs, as well as the combination of classes viathe HI.

Committee Response: Site soil results for PCBs and PCDD/PCDF were evaluated in theTier 1 Screening Level Ecological Risk Assessment (SLERA) submitted to the EPA onFebruary 28, 2002 (CEC 2002). Trie PCBs detected in site soils were compared to theBTAG screening criteria of 100 \ig/kg (see Tables 4a and 4b; CEC 2002). ThePCDD/PCDFs detected in site soils were converted to a 2,3,7,8 TCDD ToxicEquivalency Factor (TEF) using the approach of VandenBerg et al. (1998) andcompared to a screening criteria developed by Efromyson et al. 1997 (i.e.,Lowest-Observed-Adverse-Effect-Level (LOAEL) divided by 10; see Tables 4a and 4b,CEC 2002). The approach that was used by CEC and the Committee was approved byEPA during the Work Plan development and the Phase 2 scoping documents. Thisapproach allowed for an evaluation of each parameter class separately via individualHQs, as well as well as the combination of classes via the HI.

Sediment Data. The level of sediment contamination within the sampled streamreach is not unexpected in light of the gradient and tendency for scouring in highwater events. BTAG again recommends a reconnaissance of the downgradientreaches of the stream for major depositional areas prior to or at its confluence

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with the Ohio River. Any identified deposits should be sampled in Phase 3 unlessit can be demonstrated that the mass of PCB/PCDD/PCDF present on the site(and previously remediated) accounts for at least 75% of the estimated massused during site operations.

The memorandum states that no site-related impacts were observed. However,statistical analyses (T-tests) indicate that concentrations of lead and arsenic aresignificantly higher downgradient of the site (samples 1-18) than upgradient(samples 19-24). At 11 of 18 downgradient locations, the lead concentration insediments is between the threshold and probable effects levels for aquaticorganisms. As the objective of the SLERA to be performed in Phase 3 is toevaluate the potential effects for all the COPCs, conclusions about the impactsare premature.

BTAG recommended that grain size and total organic carbon (TOG) bedetermined for sediment samples. TOC data are presented in Appendix E, butgrain size data seem to be missing.

Committee Response: CEC met with BTAG personnel at the site and selecteddepositional areas in Montour Run upstream, adjacent to, and downstream of the sitefor the sediment sampling. Seventeen sediment samples were collected adjacent to ordownstream of the site, in a stream reach covering approximately one mile, and noneresulted in detectable levels of PCBs. Based on these results, the Committee believesfurther sampling is not warranted. Furthermore, Montour Run downstream of the sitehas likely received discharges from other point and non-point sources. Any potentialfuture positive results in this reach of Montour Run would then be confounded by thispossibility.

The Committee agrees that comments about impacts are premature. However,Appendix C of the SLERA (CEC 2002) presents a statistical comparison of upstreamand downstream sediment samples for arsenic and lead. The upstream anddownstream sample locations are the same as described by EPA above. Anappropriate statistical test, the Wilcoxon Rank Sum Test, was used to evaluate thesediment data for arsenic and lead. According to EPA guidance, the Wilcoxon RankSum Test is valid irrespective of distributional assumptions (normal v. non-normaldistributed data). No statistical differences were found in sediments between upstreamand downstream concentrations for arsenic (Appendix C, page 14) and lead (Appendix

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C, page 17).

Grain size was determined for the individual sediment samples. The results weresubmitted to EPA under separate cover (Memorandum from P.W. Tomiczek to B.Khona, dated September 6, 2001) and will be included as an appendix in the revisedPhase 2 Technical Memorandum.

Proposed Phase 3 Investigation Scope. The memorandum states that the SLERAwill take into account area-use factors and bioavailability. The USEPA guidancefor SLERAs calls for 100 percent occupancy and bioavailability to ensure that allpotential COCs are carried to the baseline ecological risk assessment. Ifnecessary, site-specific adjustments to the assessment can be made during theproblem formulation.

Committee Response: The SLERA performed for the site (CEC 2002, see page 26)follows USEPA guidance and assumes 100 percent occupancy and bioavailability of allchemicals of interest (COIs). The text in the memorandum was incorrect and will berevised.

1.5 DAWNA YAWNACCI (DEP) COMMENTS

Comment 1. Figure 8 depicts shallow groundwater flow. It should be identified assuch and a flow map for the bedrock: wells should also be presented. Also, itwould be helpful if all maps showing groundwater information either presentedinformation for shallow and bedrock groundwater separately on different maps orclearly differentiated between the shallow and bedrock information on the samefigure. This goes for tables as well.

Committee Response: The title of Figure 8 will be revised to indicate that it representsshallow groundwater flow. In CEC's opinion, a representative groundwater flow map forthe bedrock system cannot be prepared with only three data points (MW-1B, MW-5B,and MW-6B). Groundwater elevation data from the shallow and bedrock system will beclearly differentiated on tables and figures in the revised Phase 2 TechnicalMemorandum.

Comment 2. Will all wells be sampled and water levels collected during Phase 3?At least two sampling events per well are needed to adequately characterize

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groundwater quality at this site.

Committee Response: Water level measurements will be collected from all wells duringthe Phase 3 investigation. Groundwater samples will be collected from the monitoringwells installed during the Phase 1 and Phase 2 investigation (BG-1, BG-2, MW-1through MW-'12, MW-1B, MW-5B and MW-6B) and the new wells installed during thePhase 3 investigation.

Comment 3. It appears that an analysis for cis-DCE in groundwater is not beingrun. If biodegradation of the TCE at the site is a going to be a consideration,information on the distribution and concentration of cis-DCE will be important.

Committee Response: The Committee agrees with this comment, and cis-DCE andtrans-DCE will be analyzed individually for future analyses.

Comment 4. It is unclear why the two bedrock wells proposed for phase 3 areconcentrated near the northeastern portion of Montour Run. An analysis of whatis now known about bedrock groundwater flow direction would be useful inplacement of off-site wells. Are we sure that groundwater in the bedrock flowstoward Montour Run? The Ohio River is not too far from this site and may exert aninfluence on groundwater flow. At least three shallow/deep well pairs are neededto monitor off-site groundwater quality and better define groundwater flowdirection.

Committee Response: The Committee agrees that additional bedrock monitoring wellswill assist in determining groundwater flow directions in the bedrock system. TheCommittee agrees to install one bedrock well at the proposed MW-13 shallow welllocation (creating a shallow and deep well pair). In addition, the Committee agrees toinstall an additional well cluster (one shallow well and one bedrock well) across thecreek from MW-13. The Committee believes that, installation of these three additionalwells will be sufficient to define groundwater flow direction and evaluate the quality ofgroundwater discharging from the lagoon area to and/or beneath Montour Run.2.0 CLOSING AND REQUEST FOR EPA APPROVAL OF PHASE 3 SCOPE

We appreciate your time and consideration of the issues that have been identifiedin this letter. We trust that the proposed actions summarized in this letter will beagreeable to EPA. If the proposed revisions to the Technical Memorandum and

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Phase 3 investigation scope outlined above are agreeable to EPA, we understandthat you can indicate your approval on the signature line provided below. CECwill then finalize the Technical Memorandum and implement the Phase 3remedial investigation activities in accordance with the-'above-described scope.Please feel free to call us with any questions or comments.

Very truly yours,

CIVIL & ENVIRONMENTAL CONSULTANTS, INC.

Karen E. Souza, P.G.Project Manager

Paul W. Tomiczek, III, R.E.M., P.E.Senior Project Manager

APPROVED BY:Bhupi D. Khona, Remedial Project Manager

DATE:

cc: Breslube:Penn Joint Steering CommitteeDawna Yannacci, DEP Southwest RegionMary Jo Apakian, COM Federal

RC-98838-0602.A25/I