AR305969of the simulation. In addition to ground water elevations, transport of only one contaminant...

UNTIED STATES ENVIRONMENTAL PROTECTK\ REGION »

841 Chestnut BuftfngPhtedetpte, Pennsylvania 19107

May 8, 1992

Mr. George B. MarkertSenior ConsultantEnvironmental AffairsBridgestone/Firestone, Inc.1200 Firestone ParkwayAkron, Ohio 44317

Mr. Barry BelfordDirectorCecil County Department of Public WorksRoom 308 Court HouseElkton, Maryland 21921

Re: RI Report and Preliminary FS ReportWoodlawn Landfill Site

Dear Messrs Markert and Belford:

Enclosed please find the comments of EPA and the MarylandDepartment of the Environment regarding the subject documents.

Please call me at (215) 597-9238 if you have any questions.

Sincerely,

Debra RossiRemedial Project ManagerDelaware/Maryland Section

cc: John FairbankKevin GaynorMark GrummerPat HilsingerAlan Jacobs

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FOR THE WOODLAWN LANDFILL RI/FS. CECIL COUNTY. MARYLAND

Pag* BS-5, Phas* IV - Additional ri*ld Work, first bullet:What screening criteria were used for reporting contaminantsfound in the borings in waste? Only vinyl chloride, BEHP, TCEand 2-butanone are mentioned. Several contaminants in additionto these were found in the borings in waste, includinghalogenated organic compounds, polynuclear aromatic hydrocarbons(PAHs) and inorganic parameters.

With respect to the borings in waste, it is stated that BEHP"was found throughout the Site." Indicate that the levels ofBEHP found in the waste samples collected from cells B and C(borings in waste ITW-7 and ITW-8) were two to three orders ofmagnitude greater the levels measured in samples of fill materialobtained from other borings. Also see the discussion on page l-15 of the preliminary FS Report: BEHP was not found in thesubsurface samples collected from boring in waste ITW-2; samplesfrom ITW-1, -3, -4 and -5 were not analyzed for semivolatiles(therefore, it cannot be concluded that BEHP is present (or notpresent) in these areas); BEHP was detected in a sample from ITW-6 (5000B Mg/kg), however this result may be due to laboratorycontamination (since BEHP was found in a blank at a comparablelevel).

Pag* ES-7, »*eond paragraph: Please delete the lastsentence which states, "Contaminants from the Site have not beendetected in the Unnamed Creek."

Pag* BS-8, s*oond paragraph: Please specify the EPAstandards that are referenced here. How were the "keyconstituents of concern" identified? Isn't bis(2-ethylhexyl)-phthalate a constituent of concern?

Pag* E8-8, third paragraph: what criteria were used toevaluate environmental media "falling within U.S. EPA target riskrange?" Is the author referring to human carcinogenic risk?

Pag* BS-8, fourth paragraphs To which U.S. EPA standards isthe author referring?

P»g* BS-9, fifth bull*t: Levels of aluminum in the creekexceeded the AWQC for chronic exposure (please see commentsbelow).

Pag* BS-9, s*v*nth bullet: it is stated, "No streamsediment constituents exceeded U.S. EPA guidance criteria."Which criteria are referenced here?

Pag* BS-9, bottom: It is stated that, based on sitecharacterization work, "there is no indication that theenvironment is being significantly adversely affected by the

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Site." Please refer to the comments below regarding section 6 ofthe Report. These comments must be satisfactorily addressedbefore conclusions can be drawn regarding the impact of the siteon the unnamed creek.

Pag* ES-10, fourth bullet: As we discussed on March 19,1992 (conference call among George Markert (Bridegstone/Firestone), Alan Jacobs and Mark Hardner (IT), John Fairbank(MDE) and Debra Rossi (EPA)), EPA approval of the treatabilitystudies results is not required prior to transmittal of the FS.As we agreed, the results of the treatability studies will beincluded in the appendices of the final FS Report; EPA willreview the treatability studies data when it is conducting itsreview of the final FS Report.

Section 1.2.1, Pr***nt Day sit* Description, saeondparagraph: Please note that Section 300.400(e)(1) of the NCPdefines "on-site" as "the areal extent of contamination and allsuitable areas in very close proximity to the contaminationnecessary for implementation of the response action."

Section 1.2.2, sit* History: Please indicate that thelandfill is unlined and describe the position of waste materialwith respect to the water table and perched water zones.

Pag* 1-5, s*oond paragraph: Please revise the last sentenceto show that waste fluids in the concrete tank are trucked to awastewater treatment plant.

Pag* 1-5, third paragraph: EPA did not request that theCecil County Department of Public Works hire ERM to study theimpact of the original transfer station septic system on thesite. EPA was informed on August 15, 1990, that the Countyintended to retain ERM for remedial investigation of the transferstation septic system area. EPA approved of the County'sselection of contractor in a letter dated August 16, 1990.

Pag* 2-1, tabl*: The Phase III Report was approved of onNovember 25, 1991.

Section 2.1.1, Surfac* Geophysical Survey: Please explainthe objectives of the magnetic survey and the electromagnetic(EM) survey. It is stated in section 2.1.1.1 that the objectiveof the magnetic survey was to delineate locations of buriedferrometallic material, and the results indicated the presence ofmagnetic anomalies. Please explain why no field verificationsteps were considered or performed. Anomalies identified by theEM survey were similarly not field-checked. Please explain howthis information was used in the remedial investigation.

Pag* 1-13, first paragraph: The discussion of why these

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four organic compounds were chosen to evaluate areas requiringadditional investigation is unclear.

Section 2.1.2.2, M*arby Domestic W*ll«: Has it beenconfirmed that all domestic wells listed in Appendix D of theDWP-1 are bedrock wells? Is the well at P-506 listed in AppendixD?

Pag* 2-15, last paragraph: It is stated, "No chemicalcontamination has been detected in any of the domestic wellssampled." This statement is inaccurate. Does this statementrefer to sampling conducted by the County Health Department overa certain period of time? Please review and clarify.

Pag* 2-20, Obj*otiv*s of th* Soil-Gas Survey: It is statedthat the objectives of the soil-gas survey were to approximatethe potential migration routes of the VOCs in ground water, andto determine the location of additional monitoring wells. Notethat the use of soil-gas contours for defining the boundary of acontaminant plume in ground water is frequently unsuccessfulbecause compounds possessing low to moderate air/waterpartitioning coefficients are not present at high enoughconcentrations in soil gas to be detected, and because compoundscharacterized by high partitioning coefficients have usuallydiffused into soil pore spaces beyond the plume.

Pag* 2-23, Interpretation: Explanations regarding theabsence of soil-gas anomalies in the cell B/C area, and the weakanomaly near the presumed location of cell A are offered. Pleaseacknowledge that the cell contents may have indirectlycontributed to VOC concentrations in soil gas via dissolution ofcontaminants of the cell material into leachate and ground water,and subsequent migration of the leachate and ground watercontaminants into soil-gas.

Pag* 2-24, second paragraph: It is stated that thedistribution of individual target compounds follows thedistribution of total VOCs (toluene equivalent). The datapresented in the figures in Appendix B does not support thisconclusion (particularly with respect to concentrations of vinylchloride versus total VOC concentrations in soil gas).

Pag* 2-24, bottom: It is stated in the bullet at the bottomof the page that the sludge in cells A, B and C is "suspected tohave contained" residual vinyl chloride monomer (VCM). Analysesperformed on the sludge generated at the Perryville Firestoneplant confirmed the presence of residual VCM in the sludgematerial. Analysis of a cell C sludge sample (collected fromboring in waste, ITW-7) also confirmed the presence of VCM in thesludge material. Therefore, please indicate that the sludge did.contain VCM.

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Pag* 2-26t third bull*t: Do not discount the possibilitythat vinyl chloride which has leached from the sludge materialinto leachate and ground water may be released into the soil gasat some distance from the sludge disposal cells.

Pag* 2-29, s*v*nth bull*t: What is the basis for theinference that the direction of movements of solutes(contaminants?) in the surficial soils follows the direction ofground water flow and the slope of the bedrock surface? How wasthis preliminary conclusion applied in subsequent phases of theremedial investigation? How is "surficial soils" defined?

Pag* 2-29, last bull*t: Lack of contamination inresidential wells does not confirm that contaminants from thesite "did not migrate outside the landfill boundaries." Pleasespecify which domestic well analyses are referenced here. (Whenwere the samples obtained? Who1 collected the samples?)

Section 2.2, Phas* II - sit* Characteriiation: Pleaseinclude a summary of ground water evaluation findings formonitoring wells and domestic wells, as in section 2.3.5 (PhaseIII - Groundwater Evaluation) of the Report.

Pag* 2-48, first paragraph: It is stated that results werevalidated according to the guidelines referenced in section2.6.3. Please specify the document in which this section may befound.

Pag* 2-53, third and fifth paragraphs: Please indicate thedepth measurement reference point (i.e., 63.0 feet and 44.0 feetare below ground surface (BGS) measurements).

Pag* 2-55, Results, third paragraph: Explain how thegneissic granite and metadiorite respond differently to faultingand weathering, and the expected differences in porosity andconductivity between these two rock types.

Pag* 2-56, sixth bull*t: Please indicate the limited scopeof the simulation. In addition to ground water elevations,transport of only one contaminant (vinyl chloride) was simulatedwith the computer model.

Pag* 2-64, third bull*t, fourth sent*nc*: Refer to "currentpumping conditions" rather than "current conditions."

Pag* 2-65, second paragraph, fifth **nt*no*: Please explainthe basis for the statement that bedrock does not produceappreciable yields below the upper 50 to 60 feet.

Pag* 2-65, third and fourth paragraphs: In the descriptionof the development of the observed water level map, the statement

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is made that "data points from outside the study area" were used.However, these data points are not included in Figure 8(Appendix D). Please show these data in the figure.

Pag* 2-66, Mod*l Input Param*t*rs: This section presentsall model input, not just the parameters. Therefore, pleasedelete the word "parameters" from the title.

Table 30 in Appendix D shows a retardation factor of 4 asone of the model input parameters. Please correct this error.

Pag* 2-67, middle: Again, not all of the data described onthe bottom half of the page are parameters. Please replace theword "parameters" with the word "data."

Pag* 2-68, ••cond **nt*nc*: Please replace the word"parameters" with the word "data."

Pag* 2-68, Modal D*v*lopm*nt and Calibration: The title ofthis subsection does not describe the material that follows.Please provide descriptions of flow and solute model developmentprocedures and results, and descriptions of predictivesimulations of future ground water use scenarios.

Pag* 2-69, second bull*t: Please discuss the reasons forselecting each of the boundary conditions here. Table 39provides a description of the constant-head boundary, only. Whynot provide a graphical representation of the boundary conditionsby overlaying them on the observed water level map?

Pag* 2-70, Model Calibration: Is the observed water levelcontour map shown in Figure 8 representative of steady-state flowconditions? If so, is it reasonable to assume that the watertable is still under steady-state, despite the ongoing groundwater pumping?

Pag* 2-71, s*cond paragraph: Statistically checking whetherthe calibration criterion has been reached is not the same asverifying the model calibration.

Pag* 2-72, Sensitivity Analysis: Please delete reference tothe sensitivity of steady-state ground water flow model storage-dependent parameters such as porosity.

The sensitivity of the model to hydraulic conductivity (orrecharge rate) does not confirm that the assigned values providethe best match to field conditions. It only provides a measureof the variations in the simulated heads, given perturbation ofthe hydraulic conductivity (or recharge rate).

Pag* 2-73, Solut* Transport Modal, third paragraph: Were

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the loading rates the only input data that were varied during thesolute transport model calibration? If so, please providejustification.

Fourth paragraph: Does the discussion of loading ratesrefer to loading rate per unit volume (or mass) of sludge? Ifso, please clarify, and explain the basis for the hypothesis that"loading beneath Cell B/C may not be as great as loading in areaswhere the same quantity was placed as a disseminated mass."

Pag* 2-75, first paragraph: Please specify whether SWIFTsimulates biodegradation or not.

Pag* 2-77, last paragraph: Metal analyses data formonitoring wells and domestic wells is presented here. There isno indication in the text, however, of whether the reportedresults represent filtered or unfiltered samples. Thisinformation should be provided in this data summary.

Pag* 2-79, Groundvater Modeling Findings: This sectiondiscusses the "findings" from the application of the ground watermodel to the site. Since findings are results, findings cannotreally be "based on results," as stated at the top of page 2-79.The results should reflect how well the model simulates existingsite conditions.

As stated on page 2-79, based on current-condition solutetransport modeling, the site-related vinyl chloride plume doesnot extend to the group of domestic wells located northeast ofthe site. However, irrespective of model predictions, vinylchloride has been detected in domestic well P-309, which islocated northeast of the site. This fact cannot be ignored, andmay call into question the accuracy of the model. Perhaps itshould be stated that the model slightly underestimates theextent of vinyl chloride migration and, therefore, modelpredictions may also be a slight underestimation.

Pag* 2-79, Groundvatar Flow, fourth bull*t: The range ofhydraulic conductivity values presented here (0.1 to 45 ft/day inmodeled area; 0.1 to 0.6 ft/day in landfill area) represents therange of values used to construct the calibrated model. Modelingresults do not "indicate" that the hydraulic conductivitieswithin the modeled area fall within the model input ranges, asstated. Please rephrase this section.

Pag* 2-79, Vinyl Chlorid* Transport, first bullet: Resultsfrom the solute transport model do not "indicate that vinylchloride in the groundwater is restricted to the immediate areaaround the Site." Rather, the current condition simulationreflects the present extent of the vinyl chloride plume, asdetermined by field observation.

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Pag* 2-83, Methodology: Surface water and sedimentsampling locations which are not depicted in Figure 4 are shownin Figure 5.

Pag* 2-86, last s*nt*nc*: Is there evidence that provesthat ground water is not found at depths below the upper 50 to 60feet of bedrock? What is the degree of uncertainty regardingthis statement?

Section 2.4.9, Interim R*m*dial Xaasur*: It is stated thatthe potential source of vinyl chloride is one of the IRM topicsdiscussed in the sections that follow, although no suchdiscussion is included.

Pag* 2-96, last paragraph: Although BEHP was detected inall waste borings that were analyzed for BNAs (except ITW-5), thelevels of BEHP found in the waste samples collected from cells Band C (borings in waste ITW-7 and ITW-8) were two to three ordersof magnitude greater the levels measured in samples of fillmaterial obtained from other borings. (Sample ITW-10A, whichcontained 13,OOOE/15,OOOD ug/kg BEHP, was a surface soil samplecollected from the top six inches of soil.) Please indicate thisin the discussion. Also note (page 2-97, top) that sample ITW-10A was representative of the 0- to 6-inch interval, rather thanthe 0- to 5-foot interval, as stated.

Section 3.2.3, Climatology: Please provide references.

Section 3.3.2.1, fourth paragraph: A conceptual figurewould be helpful in the explanation of the contact.

Saction 3.3.2.2, fourth paragraph: The first sentence maybe misinterpreted as meaning that metadiorite is the uppermostrock unit encountered in wells ITB-1, -2, and -3. Please clarifythat the metadiorite is the uppermost rock unit encountered inITB-2, only, rather than the "borings" in the northwest part ofthe site.

Pag* 3-13, third paragraph: Please reference theappropriate potentiometric surface maps.

Section 4.0, Matur* and Extent of contamination: Contourplots for individual contaminants in various environmental mediaare referred to throughout this section. The treatment of non-detects in deriving these contour plots is not discussed,however. This information should be included in the Report.

Semivolatile organic analyses were not performed onsubsurface waste/soil samples from all of the borings in waste.The text, and figures in Appendix H of the Report do not reflectthis information. For example, the isopleth/contour maps of

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send/volatile contaminants in subsurface soils (Appendix H) chartthe location of borings from which samples were never collectedfor semivolatile analyses (ITW-1, ITW-3, etc.). This seems tosuggest that these locations are data points.

Pag* 4-2, third paragraph: Mr. Duke and Mr. Nester areemployed by Investigative Consultant Services, Inc..

Pag* 4-2, fourth paragraph: Please provide the source ofthe information regarding cell B trench dimensions. It is statedthat "it is known that at least several million pounds of PVCsludge were placed into Cells B/C." Was this informationobtained from manifests (or the cover letters from FirestonePlastic Company which accompanied these manifests)? Pleaseprovide a reference (or references) for the information regardingthe volume of PVC sludge disposed of in cell A and cells B/C andspecify the volume of material disposed of in the cells,, (Pleaseprovide a more precise measurement than "at least several millionpounds.")

Pag* 4-2, fifth paragraph: Please reference ERM's draft RIReport (March 11, 1992).

Pag* 4-3, second paragraph: Can any conclusions be drawnfrom the ground water trends shown in Appendix I?

Pag* 4-4, first paragraph: What criteria were used toidentify the "10 most toxic" contaminants (hazard index, excesslifetime cancer risk)?

Section 4.2.1, Wast* Borings: If the waste boring sampleshad been collected in a grid, then contour plots for selectedcontaminants that are presented in this section and in Appendix Hmight be useful. With so few samples, they are of questionablevalue, especially when a contaminant was detected in only onesample.

First paragraph: The borings were completed to define thevertical and lateral extent of a source of contaminants.

Second paragraph: Please state, "At least three sampleswere collected and analyzed from each of Borings-in-waste ITW-1through ITW-10."

Third paragraph: Please specify whether calculation ofchild cancer risk (from ingestion, etc.) is based on results forsurface samples, or surface and subsurface samples.

Section 4.2.1.1, Surfao* Soils/Wastas: On pages 4-6, 4-28,4-31 and 4-32, incorrect units are presented for inorganicconstituents in soil, in the analytical summary tables presented

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in Appendix E of the Report, the concentrations of metals in soilare reported in terms of mg/kg, not /ig/kg. These typographicalerrors should be amended in the final Report.

First bullet: A CRDL of 5 Mg/kg is specified here forberyllium. However, in Table 4 of Appendix E, the CRDL forberyllium is reported to be 5 Mg/1- Please review/correct thedata.

Pag* 4-9, first bull*t: It is stated, "Since BEHP has beenfound in all but two of the soil borings analyzed for BEHP..., ithas been found, essentially, over all of the Site where wasteborings were drilled." Please see the comments above regardingthe distribution of BEHP in subsurface soil samples and revisethis statement accordingly.

Pag* 4-13, first paragraph: EPA sampled domestic wellssurrounding the site in August 1991.

Pag* 4-15, Vinyl chlorid*: Please explain the apparentdiscrepancy between the vinyl chloride concentration plot inAppendix H (Vinyl Chloride, Groundwater, Round 2), and thecurrent condition simulated vinyl chloride concentrations (Figure15, Appendix D).

Section 4.3.1.4, Carcinogenic Inorganic Analytas: A cleardistinction should be made between filtered and unfliteredmonitoring results for inorganic analytes. Both filtered andunfiltered domestic well samples are referenced in this section,yet page 6-9 states that all residential well samples wereunfiltered. Please clarify this issue.

Pag* 4-21, L*ad: According to the description here, lead isa "noncarcinogenic inorganic analyte." This is an incorrectstatement. Although a carcinogenic potency factor (CPF) is, asyet, unavailable, EPA has classified lead as a Group B2 (probablehuman) carcinogen. Page 4-21, as well as pages 4-25, 4-29 and 4-30, should be amended to reflect this point.

Section 4.4.1, Surfao* Wat*r, s*cond paragraph: Pleaseprovide a basis for selecting the analytes listed here forfurther discussion. Was evaluation based on risk to human healthposed by the contaminants, potential for environmental impacts,both? Section 4.4 (third paragraph) seems to suggest that theanalytes were selected on the basis of the BLRA, only, but thisis not entirely clear.

Section 4.4.2, S**ps and Associated 8*di»*nts: Please seethe previous comment.

Section 5.1, Potential Routes of Migration: Please indicate

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that the landfill is unlined.

Pag* 5-3, last paragraph: Given that the purpose of thisparagraph is to describe current conditions with respect to theextent of vinyl chloride contamination, it should discuss theresults of ground water sampling rather than the solute transportmodel simulation of vinyl chloride concentrations.

Pag* 5-4, last paragraph: It seems unlikely that overflowfrom the septic system would result in "seepage flows to theretention basin to the southwest" or would cause "seep waters[to] spill over the decant riser in the retention basin and flowthrough the swale and into the Unnamed Creek." Either verifythat septic system overflow produced these results, or delete thefinal sentence from this paragraph.

Section 5.2.2.1, Organic Compounds: The introduction ofthe phthalate esters includes a brief summary of the type ofcompounds detected but omits the type of matrix. Please providethis information.

Section 5.2.2.1, first paragraph: This paragraph shouldalso introduce the pesticides.

Pag* 5-8, Volatil* Organic*: Please indicate which of thecompounds in the second sentence are chlorinated and which arenonchlorinated.

Pag* 5-9, Adsorption/Dasorption: Log Koc values are notprovided in Table 5-1.

Pag* 5-13, Summary: Please include a statement regardingthe role of bioaccumulation of phthalate esters found at the sitein the summary of fate and transport mechanisms.

Pag* 5-13, Solubility, last s*nt*nc*: Is it meant that PAHs(rather than BNAs) are generally less soluble than acidextractable compounds?

Pag* 5-14, Summary: Is it suggested that the water samplesshould be analyzed for humic acid? Were the PAHs detected at alevel that suggests that they are of little importance at thissite? Please justify the conclusion.

Pag* 5-16, Summary: Please include a statement regardingthe role of bioaccumulation of pesticides in this discussion.

Section 5.2.2.2, Inorganic Chemicals: There is a great dealof technical detail provided in this section of the Report.Please explain how this information is related to the site. Whatdoes this information mean in layman's terms?

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Pag* 5-22, Summary: The last sentence is unclear. Pleaseconclude this section with a statement indicating whether thereis a potential for off-site migration of inorganic contaminantsof concern.

Saction 6.0 (section title?): Pages 6-15, 6-17, and 6-28,Appendix L, and Table 6-17 refer to the use of the Summersmethod, the assumptions inherent to it, and the predicted groundwater concentrations of contaminants based on their maximum or95% upper-bound subsurface soil concentrations. The followingcomments relate to the Summers method.

1. Frequent reference is made within the Report to cell B/Csubsurface "soils." Please clarify whether this term encompassesthe PVC sludge material, and whether the Summers method was usedto predict ground water impacts resulting from leaching fromcontaminated soils, or contaminated soils and wastes. EPAgenerally uses the model to calculate an acceptable subsurfacesoil cleanup level based on the concentration of a contaminantthat would adversely impact ground water. Although use of themethod to predict ground water concentrations based on subsurfacesoil concentrations does seem reasonable, application of theSummers model to PVC sludge material has not been justified.

2. The following comments are made with the understanding thatthe Summers model was used to evaluate potential ground waterimpact of subsurface soils, rather than waste material.

a. The input values that appear to have been used are notnecessarily as conservative as implied. While Table L-l showsthe values of site-specific parameters that were used, nocontaminant-specific values are provided. However, back-calculating through the Summers model shows that if a value of4,980 M9/kg is used as the 95% upper-bound soil concentration forvinyl chloride (shown in Table 6-10) to predict a ground waterconcentration of 80.4 ng/1 below cell B/C (shown in Table 6-17),then the value used for Koc was 134 and Kd was calculated as5.36, based on the foc of 0.04. Note that a different set ofvalues was used in deriving input parameters for the solutetransport model (Phase III): the foc for soil at the site wascalculated to be 0.018 in the derivation of the retardationfactor for vinyl chloride, and the Kj for vinyl chloride waspresented as ranging from 0.046 to 0.280 (Appendix C of the PhaseIII Report). Appendix C of the Phase III Report also shows adifferent equation for deriving K^ for vinyl chloride than isshown on page L-3 of the final RI Report. Finally, Table 5-1presents a value of 8.2 for the Koc of vinyl chloride. Clearly,IT should be consistent, and all contaminant-specific values thatare used should be presented.

b. Please justify the use of 4.4 ft/day for hydraulic

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conductivity since slug tests resulted in a range of values.

Section 6.2, Identification of Chemicals of PotentialConcern, second paragraph: Chemicals of potential concern shouldbe selected using the criteria presented at the bottom of page 6-3. In general, the unavailability of toxicity criteria for agiven chemical does not automatically preclude the selection ofthat chemical for inclusion in the BLRA. If toxicity criteriaare unavailable for a chemical of potential concern, such thatthe risk associated with exposure to that chemical cannot bequantified, a discussion to reflect this should be included inSection 6.3.2.4 (Uncertainties Related to Toxicity Information).

Section 6.2.1.1, Background Data: Table 6-2 should show acomparison of ground water background concentrations to siteconcentrations for all inorganics for which site samples wereanalyzed (i.e., inorganic analytes on the TAL, minus selenium andantimony). Also, Table 6-3 should show background and site soiland sediment concentrations for all inorganics. Section 6.2.1.1should include a discussion of the criteria used to determinewhether an inorganic analyte was detected at levels significantlyelevated above background levels (for all media evaluated).

Section 6.2.1.3, Delineation of Media-Specific Sourc* Areas,third paragraph: The sample collected from cell B/C which wasfound to contain 7.95 mg/kg of VCM was apparently a waste sample.Why is it characterized as a soil sample? The text refers to"the surface and subsurface soils of Cell B/C." Please clarifythat the "subsurface soils" contain PVC sludge, and state whetherthe soils underlaying the sludge are also considered here.

Section 6.2.2, General Site-Specific Data EvaluationConsiderations, first paragraph: The reference for theconversation with Ms. Dawn loven should be included in thereference section. Please also see the comment above regardingthe second paragraph in section 6.2 of the Report.

Page 6-8, third paragraph: It is stated, "The methanolextraction, which was used for some of the Cell B/C sludgesamples, overestimates the mass of VOC that would be expected tobe released from the sludge under normal leaching conditions."One may argue that both laboratory extraction proceduresdescribed on page 6-8 underestimate the mass of VOC available forleaching. Please verify the statement enclosed in quotationmarks above, or delete it from the Report. What is the basis forthe stated expectation that some mass of VCM would remain trappedwithin the vinyl chloride polymer? How was the element of timeconsidered in modeling leaching phenomena? Is the "leachability"of the sludge material expected to change with time? If so, why?

section 6.2.3, Groundwater: Please state whether filtered

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or unfiltered samples were used to generate ground water datasummary statistics for on-site and off-site nonresidential wells.

Section 6.3.1, Exposure Assessment: The potential exposurepathway for inhalation of volatilized constituents from soil byon-site workers and off-site residents should be qualitativelyaddressed in the text of the report.

Page 6-15, first bullet: The child receptors are identifiedas 6 to 14 years old. U.S. EPA 1989a specifies a skin surfacearea of 9,310 cm2 for a male child between 6 and 9 years of age.The skin surface area presented underestimates the available skinsurface area of the 6 to 14 years old receptor.

Page 6-15, third bullet: As stated, heavy metals are notusually absorbed dermally to an appreciable extent due to lowpermeability factors. For this reason, the dermal pathway wasnot evaluated for dissolved metals in the BLRA. It should benoted, however, that according to recent EPA guidance entitledDermal Exposure Assessment: Principles and Applications (January1992), dermal exposure to metals dissolved in an aqueous phaseshould be assessed quantitatively. (Since it is not anticipatedthat exposure to metals via the dermal pathway will contributesignificantly to the overall risk at this site, perhapsconsideration could be given to handling this particular exposurein a qualitative, rather than a quantitative, manner.)

Page 6-15, surface Soil: Perhaps workers at the transferstation should be addressed as on-site receptors of windblownsite dust.

Page 6-16, second bullet: The assumed soil ingestion rateof 200 mg/day is the ingestion rate for a 1 to 6 year old child,yet child receptors are identified as 6 to 14 years old. Pleaseaddress this discrepancy.

Page 6-16, third bullet: The skin surface area of 3,910 cm2presented here is apparently the 50th percentile surface area ofonly the arms, hands and legs of a male child between 6 and 7years of age (U.S. EPA, 1989a).

Page 6-16, fourth bullet: As indicated here and on page 6-18 (sixth bullet), organic chemicals in soil were assumed to beabsorbed dermally to the following extent: volatiles =25percent; semi-volatiles » 10 percent; and metals » 1 percent.However, according to the recent dermal guidance (citedpreviously in the Report), only exposure to 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD), polychlorinated biphenyls (PCBs)and cadmium in soil can be quantitatively assessed with anyappreciable degree of accuracy. All other contaminants should beevaluated in a qualitative mode. Therefore, consideration should

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be given to deleting this pathway (i.e., dermal exposure tocontaminants in soil - except for TCDD, PCBs and cadmium) fromthe BLRA.

Page 6-18, top: What is meant by the "predicted leachateconcentrations in the on-site groundwater?" The Summers methodwas used to model concentrations of contaminants in ground water.Please eliminate the word "leachate."

Pag* 6-18, S*dim*nt: U.S. EPA, 1989a does not present skinsurface area of a child 6 to 14 years old to determine total skinsurface area of arms, hands and legs.

Pag* 6-20, second bullet: Please see the comment regardingthe third bullet on page 6-15.

Page 6-23, first paragraph: This paragraph indicates thatfor inhalation of airborne contaminants in off-site soil, anexposure time of 0.44 hours/day was assumed. This number appearsto be too low. The derivation of this value should be discussedin the Report.

Page 6-33, first paragraph, last sentence: Typo - "E&s. donot consider...."

Page 6-34, Chemical* with No Available Toxicity Data, thirdparagraph: Please revise the second sentence as follows: "Inevaluating noncarcinogenic endpoints for PAHs, pyrene was used asa surrogate...."

Page 6-35> Adjustment of Toxicity Index: As discussed,gastrointestinal (GI) absorption factors were applied to certaincalculations in the BLRA. However, the methodology employed inthe derivation of oral toxicity criteria, such as CPFs and RfDs,must be considered. Generally, toxicity criteria are establishedbased on the adverse health impacts witnessed in experimentalanimals after exposure to specific chemicals. (Typically, thechemicals under investigation are dissolved in carrier solutionsor vehicles prior to oral administration.) From theseexperimental studies, oral toxicity criteria are established,almost without exception, based on administered dose, rather thanabsorbed dose. Therefore, since GI absorption is alreadyconsidered, albeit indirectly, in the derivation of oral CPFs andoral RfDs, it is inappropriate to adjust for this factor in riskcalculations. This is particularly true for constituentsdissolved in aqueous solutions. (For exposures involvingingestion of soil-bound contaminants, on the other hand, it maybe reasonable, in some instances, to apply correction factors forGI absorption. Such an approach may be justifiable if thebioavailability of a soil-bound contaminant differs markedly fromthat of the same contaminant dissolved in the vehicle used in

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laboratory studies.)

Page 6-38, second paragraph, last sentence: Please rephrasethis sentence. The NCP does not state that "incrementalcarcinogenic risk....should be between 10~6 and 10~4."

Page 6-39, Off-Site Residential: As indicated in Table 6-5,to determine the potential risks related to exposure tocontaminants in residential wells, the 95th percent upper boundconcentration of each contaminant in every off-site residentialwell was employed. This is not a reasonable approach, however.Any given resident in the vicinity of the site will basically beexposed to contaminants in one well only. Therefore, inevaluating the off-site risks associated with ground water, onlythe most contaminated domestic well needs to be assessed.

Section 6.3.3.7, Cumulative Current Risks and Hazards: Adiscussion of the summation of risks across exposure pathways ispresented. In deriving total site-related risks, essentially twoscenarios were assessed in the Report. In one instance, an off-site child exposed to contaminated ground water and wind-borneparticulate matter from surface soil was considered. In theother scenario, a child trespasser exposed to downstream surfacewater and sediments, site seeps and surface soil was evaluated.It is acknowledged that the exercise of combining exposurepathways for the purpose of establishing total risk at a site isfairly subjective in nature; however, it seems reasonable that achild who trespasses at the site with any degree of regularitywill probably also reside in close proximity to the site.Consideration should, therefore, be given to combining the on-site (trespassing) and off-site exposure pathways.

Section 6.3.3.8, Future Risks and Hazards, first paragraph:The last sentence states that the future risk associated withinhalation exposure to contaminated ground water is minor.However, while the cancer risk posed by inhalation may be lessthan the risks posed by ingestion and dermal contact, theinhalation risk is still in the 10~4 range. This should not bereferred to as a "minor" risk in the Report.

Page 6-49, second and third paragraphs: Please see commentsregarding section 6.0 and page 6-8, above.

Page 6-51, Upland Field Habitat: The classification ofcattails, loosestrife, and at least two rushes as uplandterrestrial species is questioned. If these species are present,they are an indication of wetland conditions and thereforeindicate that a wetland delineation should be performed.

Page 6-56, Available Fisheries Data: Information generatedprior to 1990 should be reviewed and included in order to

properly evaluate site impacts.section 6.4.2.1, Potential Exposure Pathways: The

concentration of some contaminants in seeps along the peripheryof the landfill is sufficiently high to cause concern. It issuggested that the investigator consult the AQUIRE data base, andthat this exposure pathway be addressed in this section.

Page 6-58, first paragraph: The document fails to offersupporting data for the statement that the ingestion ofcontaminants by prey organisms is not a significant exposurepathway. This may be a significant exposure pathway for theunnamed creek because some of the metals may bioconcentrate. Itis suggested that the investigator consult sources such as theAQUIRE data base for the required information. Surface waterchemical data is presented in Table 6-30, not Table 6-28.

Page 6-58, Groundvatar: The last sentence in this paragraphpertains to seeps. Have all seeps emanating from the site beenadequately defined and characterized with respect to flows(maximum), location and chemistry? Additional evaluation ofseeps and their impacts on other media (e.g., the unnamed creek)is called for.

Section 6.4.3.1, Potential Toxicity of Impacted SurfaceWater: Please see the comments pertaining to Table 6-29.Regarding the data presented in Table 6-30, according to theAQUIRE data base, maximum surface water concentrations in theunnamed creek for aluminum, barium, chromium, cobalt, copper,lead, manganese, nickel, zinc and silver are high enough topotentially cause impacts to a wide range of organisms (algae torainbow trout, and some terrestrial plant species). In addition,bioconcentration factors of some of the contaminants present areof concern. This information suggests this site is having (andprobably has had) and effect on natural resources through anumber of pathways. This information needs to be taken intoaccount when developing remedial action objectives and where anycleanup levels are developed.

It is stated that it is not appropriate to compare theresult for lead in surface water samples with AWQC for chronicexposure because the chronic exposure criteria are related tofour-day averages. If this logic is to prevail, then samplingshould be conducted to verify that lead levels do not exceed thechronic criterion.

Section 6.4.3.2, Potential Toxicity of Impacted Sediments:Provide lowest observed effect level (LOEL) concentration datafor stream sediments (in lieu of or in addition to the PugetSound data). Please include sediment grain size.

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Pages 6-66 to 6-67: The macroinvertebrate study of thestream shows similarity in species composition, diversity andevenness; however, the total organism count at the downstreamstation was roughly half that at the upstream station with regardfor the abundance of EPT of all organisms other than caddisfly.Since caddisfly are less subject to drift, the composition of EPTat the downstream station may be the result of mayfly andstonefly drift from upstream. Therefore, the EPT composition atthe downstream station may actually be an erroneous reflection ofgood stream quality conditions at the downstream station. Someexplanation should accompany these results. There is a concernthat natural conditions such as stream flow may mask adverseimpacts. Therefore, any remedial action that is implementedshould include monitoring (biological and chemical) for streamrecovery.

Section 7.2.1, Soil Contamination: The text states thatsludge was identified in only one boring in waste in cell B/C.However, the boring logs document PVC sludge in two borings:ITW-7 and ITW-8.

Page 7-3, first and second bullets: The lists areincomplete (see Table 6-9 and 6-10). What are the reportingcriteria?

Page 7-4, first paragraph: Please delete the word "across"from the first sentence.

Section 7.2.3, Surface Water, Seep, and sedimentContamination, first paragraph: What is meant by "minimalcontamination" in the seventh line? Please delete the statementthat "the evidence does not indicate that the constituentsdetected have originated from the Site," since elevatedconcentrations of site-related contaminants have been found indownstream samples.

Page 7-5, first paragraph: Same comment as above.

Page 7-6, first paragraph: Can the thickness of the finalclay later overlaying cells B/C be determined from the logs forthe borings in waste?

Page 7-6, second paragraph: This paragraph includes avariety of "uncertainties" related to the "eastern corridor" ofthe site. It is not clear how IT envisions that theseuncertainties will impact the plan for cleanup of the site.Please explain.

Section 7.4, Fate and Transport, third paragraph: Thisdiscussion is ambiguous. It is stated that the rate of groundwater movement and vinyl chloride transport is such that the

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contaminants will remain in contact with subsurface media for along time. Is it suggested that the rate of ground water flowinfluences the rate of chemical and biochemical reactions thatdegrade contaminants? Have studies been conducted to confirmthis? Please explain. Also, how does ground water (andcontaminant) velocity affect contact time with the unsaturatedsoil zone (third sentence)?

Page 7-10, fourth paragraph: The second bullet suggeststhat the summers fate and transport model has been used to modelleaching from sludge material, rather than soils. If this is thecase, demonstrate that the assumption presented in the fourthbullet , i.e., that leaching from sludge occurs as predicted bythe Summers model, is valid. Please cite references for use ofthe Summers method in this capacity.

Section 7.5.2, Summary of Ecological Risk Characterization:Please reevaluate this section based on the comments above.

Page 7-13, first bullet: site ground water, and soils whichreceived discharges from the septic system have been adequatelycharacterized to evaluate remedial alternatives for the site. Inlight of available site characterization data (including thatpresented in ERM's draft Septic System Drain Field InvestigationReport, March 11, 1992), state the basis for: the assumptionthat the transfer station septic system has resulted in groundwater contamination; the recommendation that additional studiesbe performed.

Section 7.7.2, Recommended Remedial Action Objectives: Theremedial action objectives recommended here differ from thosepresented in the preliminary FS Report. Please refer to EPA'scomments on the objectives presented in the preliminary FSReport.

Table 6-2 and 6-4: Statements should be provided withregard to whether the reported monitoring well results forinorganic constituents represent filtered or unfiltered samples.

Table 6-17: Please remove the word "leachate" from thetitle of this table.

Table 6-18: According to this table, interim inhalation andoral RfDs were derived for lead for use in the BLRA. Due to thehighly toxic nature of this heavy metal, EPA believes that it isinappropriate to apply RfD values in the assessment of leadtoxicity. For this purpose, the Integrated Uptake/Biokinetic(IU/BK) Model was developed. The IU/BK Model should be executedfor evaluating the toxic effects associated with exposure tolead.

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Table 6-29: Please correct the following ambient waterquality criteria (the criteria have been updated since 1986) :

water Qualit Criteria fucf/1)

Constituent Acute Exposure Chronic Exposure

Aluminum 750 87Silver 0.57

Figure 7: Please indicate the distance that well ITB-5 isprojected onto the cross section. Was the figure depicting thetop of bedrock elevation contours (Figure 2, Appendix D) used indeveloping this cross section? There seems to be somediscrepancy between the conceptual figure and the figure inAppendix D. What is the objective of Figure 7?

Appendix H: Contaminant concentration isopleths arepresented in Appendix H. Are the contaminants represented the"key constituents of concern" at the site? What criteria wereused to determine the contaminants that are presented? Note that1.2-dichloroethane is identified in the RI Report as a keyconstituent of concern in on-site ground water.

A Stage 1A cultural resource survey is required in order todetermine the ARAR-status of Section 106 of the National HistoricPreservation Act of 1966, as amended. Please note that thisrequirement was previously discussed in a letter and attachmentsfrom D. Rossi to G. Markert and B. Belford dated August 30, 1990.

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EPA'S COMMENTS ON THE PRELIMINARY FEASIBILITY STUDY REPORTFOR THE WOODLAWN LANDFILL RI/FS. CECIL COUNTY. MARYLAND

Ma j or Comment:

The preliminary FS Report generally follows EPA RI/FSguidance for the Feasibility Study format with the exception ofthe comparative analysis (which will be included as part of thefinal FS Report). However, screening of both the technologiesand remedial action alternatives is not performed uniformly. Forexample, the initial screening of technologies often does notinclude an analysis of the effectiveness, implementability andcost comparison in those cases where competing technologiesaccomplish the same function. In some cases, cost-effectivenessissues are raised without mentioning potential effectiveness andimplementability. In other cases, the reference to a competingtechnology that accomplishes the same function (implementabilityor effectiveness) at a reduced cost is not included.

Some of the technologies presented are not clearly described(e.g., the in-situ thermal methods and ground water treatmenttechnologies).

Specific Comments:

Section 1.2.1, Site Description, last paragraph: The firstsentence states that the site "is herein designated as theapproximate 38-acre property of the former Woodlawn Landfill."Note that the NCP (Section 300.400(e)(1)) defines "on-site" as"the areal extent of contamination and all suitable areas in veryclose proximity to the contamination necessary for implementationof the response action."

Page 1-5, first paragraph: Please see the comment regardingpage 1-5 (third paragraph) of the RI Report.

Section 1.3.2, Identification of ARARs: Please includediscussion of To-Be-Considered (TBC) materials in this sectionand its subsections, where appropriate. TBCs, which arenonpromulgated advisory or guidance issued by federal or stategovernment, are often considered along with ARARs in implementingcleanup actions at CERCLA sites. Please summarize and discusspertinent points of each ARAR/TBC in a separate paragraph.

Section 1.3.3, Chemical-Specific ARARs: Chemical-specificARARs and TBCs are discussed. It should be noted in the Reportthat, if deemed prudent by the Remedial Project Manager (RPM),health-based concentrations can serve as remediation goals,irrespective of the existence of other ARARs (such as MCLs).

Section 1.3.3.1, Groundwatar: RCRA MCLs and SDWA MCLs arediscussed here. Also include the following TBCs: EPA HealthAdvisories (non-enforceable guidelines developed by the EPA

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office of Drinking Water for chemicals that may intermittently beencountered in public water supply systems); Health EffectsAssessments (HEA) (present toxicity data for specific chemicalsfor use in public health assessments).

Section 1.3.3.1, Groundwater, first paragraph: MCLs areenforceable standards for public drinking water supply systems.While in some cases the SDWA MCLs may be applicable at a CERCLAsite (e.g, if the water is delivered through a public watersupply system having the requisite number of serviceconnections), it is more likely that these standards will berelevant and appropriate at a CERCLA site. The MCLs are relevantand appropriate requirements for the Woodlawn Landfill site. (Ifa new community well will be installed, MCLs may be applicable.)

Please note that Maximum Contaminant Level Goals (MCLGs) arepotentially relevant and appropriate standards under CERCLA S121.MCLGs are non-enforceable health-based goals for public watersupplies. The NCP requires that MCLGs shall be attained byremedial actions for ground water that is a current or potentialsource of drinking water, where the MCLGs are relevant andappropriate under the circumstances of the release.

Section 1.3.3.1, Groundvater, second paragraph: The RCRAground water protection standards (40 CFR Part 264) are part ofthe RCRA ground water monitoring requirements, which apply toRCRA-regulated units that received RCRA hazardous waste afterJuly 26, 1982. Note that even if RCRA requirements are notapplicable at a CERCLA site (e.g., if RCRA hazardous waste wastreated, stored or disposed of at a site before the effectivedate of the Part 264 standards and the CERCLA action does notinvolve current treatment, storage and disposal), they may berelevant and appropriate.

Section 1.3.3.2, Surface Water: Please note that FWQC maybe ARARs when found by EPA to be relevant and appropriate.Specifically, CERCLA section 121(d)(2)(A) states that everyremedial action "shall require a level or standard of controlwhich at least attains...water quality criteria established undersection 304 or 303 of the Clean Water Act, where such...criteriaare relevant and appropriate under the circumstances of therelease or threatened release."

Section 1.3.3.3, Soil: Include the federal soil leadguidance ("Draft Interim Guidance on Establishing Soil LeadCleanup Levels at Superfund Sites," OSWER Directive 9355.4-02,June 13, 1989) and the proposed RCRA corrective action levels forsoil and other media. According to section 121(d) of CERCLA,federal ARARs must be attained unless state ARARs are morestringent. Additionally, please acknowledge that health-basedlevels associated with direct contact exposure, and soil

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concentration thresholds calculated not to adversely impactground water will act as remediation goals for soil contaminants.

Section 1.3.4, Location-Specific ARARs: Please include thefollowing ARARs/TBCs in this discussion:

Procedures for Implementing the Requirements of the Councilon Environmental Quality on the National EnvironmentalPolicy Act (40 CFR Part 6, Appendix A), which sets forthEPA's policy for carrying out the provisions of ExecutiveOrder 11990 (Protection of Wetlands);

Ground Water Protection Strategy of 1984 (EPA 440/6-84-002),which identifies ground water quality to be achieved duringremedial actions based on aquifer characteristics and use;

National Historic Preservation Act of 1966, as amended,which establishes requirements relating to the potentialloss or destruction of significant scientific, historical orarchaeological data.

Section 1.3.5, Action-Specific ARARs: This section isinadequate. Many action-specific ARARs/TBCs for the technologiesthat are discussed later in the Report are omitted. ARARscovering air and water emissions, land disposal of treated anduntreated wastes, disposal of residuals, transportation ofhazardous materials, and protection of on-site workers, etc.,should be discussed. These include: the Occupational Health andSafety Act; United Stated Department of Transportation Rules forTransportation of Hazardous Materials; Clean Water Act (NationalPollutant Discharge Elimination System Requirements); Clean AirAct (National Ambient Air Quality Standards, National EmissionsStandards for Hazardous Pollutants); General PretreatmentRegulations (40 CFR Part 403); RCRA Land Disposal Restrictions(40 CFR Part 268); Standards Applicable to Generators ofHazardous Waste (40 CFR Part 262); Standards Applicable toTransporters of Hazardous Waste (40 CFR Part 263); Standards forOwners and Operators of Hazardous Waste Treatment, Storage, andDisposal Facilities (40 CFR Part 264); Underground InjectionControl Programs (40 CFR Parts 146 and 147); etc..

Please defer discussion of remedial technologies (i.e.,ground water treatment) to subsequent chapters of the Report.Note (in the last sentence of section 1.3.5) that NPDESrequirements pertain to discharges to surface water.

Page 1-14, first line: The words "most toxic" appear hereand in many other places in the Report without an indication asto how the determination was made. Toxicity is a complexphenomenon. How is "most toxic" defined? Please include a brief

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description and references to the full analysis (in the RIReport).

Pag* 1-14, first bullet: The concentration of berylliumdetected in ITW-3A was 1.1 milligrams per kilogram.

Page 1-14, sixth bullet: Indeno(l, 2, 3-cd)pyrene isdescribed as an inorganic compound instead of an organiccompound.

Page 1-15: All bullets are organic, not inorganic aslisted.

Page 1-15, fifth bullet: Please define DWP the first timeit is used.

Page 1-16: Inconsistencies and errors in the spelling ofcompounds are found throughout the document. The fourth bulletis listed 2-methylnapthalene ( it should be 2-methylnaphthalene);later, on page 1-23, this compound is listed with a space, butspelled correctly.

Page 1-17, third paragraph: Mr. Duke and Mr. Nester are notemployed by the Earth Technology Corporation. Please refer tothe comment on the RI Report.

Page 1-18, seventh bullet: See the comment above.Benzo(k)fluoranthene is misspelled.

Pages 1-19 to 1-20: Vinyl chloride was omitted from thelist of the 10 most toxic compounds in subsurface soils.

Page 1-20: See the comment above. 2-methylnaphthalene and2-butanone are misspelled.

Page 1-20, Cells B/C: It is stated in the last sentencethat "at least several thousand pounds of PVC sludge were placedinto Cell B/C." Elsewhere it is stated that several millionpounds of sludge were disposed of in this area.

Pages 1-21 through 1-24, all bullets: Why are borings ITW-6and ITW-9 felt to be representative of Cell B/C material? Thelogs for these borings do not indicate the presence of PVCsludge. Further, contaminants (e.g., benzo(a)pyrene) are foundin samples from ITW-6 and ITW-9 which are not found in samplescollected from ITW-7 and ITW-8. Are technologies (such asremoval or treatment) which are discussed later in the Reportwith respect to cells A and B/C intended to addresswastes/contaminated soils which extend to (and perhaps beyond)the locations of ITW-6 and ITW-9?

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Page 1-23: Please see the comment above for page 1-16.

Page 1-25, third line: The acronym BLRA is first used hereand should be defined.

Page 1-25, first paragraph: First bullet: Only ninecarcinogenic analytes are listed here. 1,l-dichloroethane (aGroup C carcinogen) is presented in the list of carcinogenic sitecontaminants. However, 1,2-dichloroethane is included in therisk characterization spread sheets (Appendix N of the RIReport), and in Table 2-3 and on page 1-42 of the preliminary FSReport. Please revise this list as necessary.

Second bullet: Lead, cadmium and benzo(a)pyrene arepresented in the list of noncarcinogenic site contaminants.However, these constituents have been classified as carcinogensby EPA. Please provide an explanation in the Report. Manganeseis listed as one of the 10 most toxic noncarcinogenic analytes.Manganese also poses problems for some types of treatmentsystems, such as air stripping systems, due to fouling. Are allanalytes which pose unacceptable human/environmental threatand/or implementation difficulties considered in this FS?

Page 1-27, fourth paragraph: It is states that "[f]our ofthe 10 most toxic carcinogenic and one of the 10 most toxicnoncarcinogenic analytes in the groundwater are classified assemivolatile organic." Which of the five listed compounds isnoncarcinogenic? Pentachlorophenol is not listed on page 1-25,and is not discussed on pages 1-27 to 1-28 with the PAHs. Pleasereview this section.

Page 1-30, third bullet: It is stated here (and on pages 1-37 and 1-40) that lead and cadmium are "noncarcinogenic inorganicanalyte[s]." However, lead has been classified by EPA as a GroupB2 (probable human) carcinogen via the oral and inhalation routesof exposure. Cadmium has been classified as a Group Blcarcinogen. If lead and cadmium were also evaluated ascarcinogens, please add a discussion of the results of the BLRA.

Page 1-32, second paragraph: Please replace the lastsentence with the following sentence: "The perched zone consistsof a thin lens of gravel underlain by a dense clay."

Page 1-33: 2-methylnaphthalene and phenanthrene aremisspelled.

Section 1.4.3.4, Carcinogenic Analytes Detected in Seep andAssociated Sediment Samples: The title of the section specified"Sediment Samples." What is the difference between seep sedimentsamples and (page 1-36) seep soil samples?

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Section 1.4.4, Off-Site Groundwater: The first sentencestates, "[a]s defined here, off-site groundwater consists of...."This raises the questions of whether it has been defined in otherways in the RI/FS process, and what effects these differingdefinitions may have on the process. Can a single comprehensivedefinition be used, or are there reasons for maintaining separatedefinitions? Please explain the introductory phrase.

Page 1-38, first paragraph: The data qualifier "J" is used,and requires explanation or reference.

Page 1-38: The comment above regarding page 1-16 applies.In the fourth paragraph, di-n-butylphthalate is misspelled; otherinconsistencies in chemical nomenclature also exist.

Page 1-39, second bullet: It is stated that beryllium wasdetected in two domestic wells. Only domestic well P-516 isdiscussed. Please specify which domestic well is being discussedin the last sentence.

Page 1-40, second bullet: Manganese is described here as aninorganic analyte, but listed as an organic analyte.

Page 1-42, second paragraph: Benzo(a)pyrene is includedhere as a carcinogenic contaminant of on-site ground water,although it is not included on the list of carcinogens on page 1-25.

Page 1-42, third paragraph: It would be useful to have thebackground concentrations reported.

Page 1-43, second paragraph: It is stated that"[uncertainties presented previously for beryllium and arsenicregarding toxicity apply to surface soil exposure as well."Please indicate where these uncertainties have been presented.

Page 1-43, last paragraph: Reference is made to Summers'fate and transport model, but no citation is given. Thestatement, "Vinyl chloride measured in the sludge using themethanol extraction method accurately predicts the mass of thiscompound potentially available for leaching," must be validated.Remove this sentence unless method validation studies can becited. Also, please cite the section(s) of the RI report thatconfirm the comment, "No other constituents in subsurface soilwould be expected to leach at concentrations deleterious to thepublic health...."

Section 1.5.2, Summary of Ecological Risk Characterization:It is stated that "there is no indication that the environment isbeing significantly adversely affected by the site." EPAbelieves that data collected during the RI provides evidence that

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the site has had (and probably continues to have) an impact onthe environment. Please reevaluate this conclusion after thecomments regarding the ecological risk assessment in the RIReport have been addressed.

section 2.1, Development of Remedial Action Objectives:Consistent with EPA's Guidance for Conducting .RemedialInvestigations and Feasibility Studies Under CERCLA (OSWERDirective 9355.3-01, October 1988), and the Guidance on RemedialActions for Contaminated Ground Water at Superfund Sites (OSWERDirective 9283.1-2, December 1988), the process for identifyingremedial action objectives and general response actions shouldspecify the following:

the contaminants and media of concern (please summarize thematerial presented in section 1.4 of the preliminary FSReport);

potential exposure pathways and potential human andenvironmental receptors for each contaminated medium (inrecognition of the fact that protectiveness may be achievedby reducing exposure as well as reducing contaminant levels)(Ground water classification is relevant to the discussionregarding potential ground water pathways and receptors;please refer to EPA's Guidelines for Ground-waterClassification (Final Draft, December 1986).);

preliminary remediation goals which take into account allpathways and receptors for each medium (as presented insection 2.1.2 of the preliminary FS Report);

volumes and/or areas of media to which general responseactions might be applied, including the area of attainmentfor ground water;

restoration time frame for ground water and other mediarequiring treatment.

Please discuss and consider each of these factors in theremedial objection/remedial alternative development process.

Section 2.1.1, Remedial Action Objectives: The remedialobjectives specified in the preliminary FS are not acceptable:they do not adequately address the expectations regarding groundwater remediation set forth in the NCP; they are vague andtherefore do not support the development of preliminaryremediation goals. The remedial objectives for the site arepresented below:

For Ground Water;

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• Prevent exposure of human receptors to contaminatedground water.

• Restore contaminated ground water for future use byreducing contaminant concentrations within the area ofattainment to levels that meet Federal and State ARARsand are protective of human health and the environmentas soon as practicable.

• Protect uncontaminated ground water and surface waterfor future use.

For Surface and Subsurface Soils/Wastes:• Prevent exposure of human receptors to contaminated

soils and wastes which present an unacceptable level ofrisk via ingestion, dermal contact and inhalation.

• Prevent migration of contaminants that would result inground water and surface water contaminant levels thatare not protective of human health and the environment.

For Seeps/Seep Sediments:

• Prevent exposure of human receptors to contaminatedseeps and seep sediments which present an unacceptablelevel of risk via ingestion, dermal contact andinhalation.

• Prevent migration of contaminants that would result inground water and surface water contaminant levels thatare not protective of human health and the environment.

• Prevent exposure of environmental receptors tocontaminated seeps and seep sediments which wouldresult in adverse impacts. (Please discuss how thiswill be accomplished in the appropriate section of theReport.)

For Air;

• Prevent human exposure to air emissions which pose anunacceptable level of risk.

• Control landfill gas in order to achieve adequateprotection of human health and the environment.

For Surface Water/Surface Water Sediments;

Please reevaluate the need to develop remedial actionobjectives for these media after the comments regarding the

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ecological risk assessment (RI Report) have been addressed.Section 2.1.2, Preliminary Remedial Action Goals: The NCP

states that "for known or suspected carcinogens, acceptableexposure levels are generally concentration levels that representan excess upper bound lifetime cancer risk to an individual ofbetween 10~* to lO~6....The 10~6 risk level shall be used as thepoint of departure for determining remediation goals foralternatives when ARARs are not available or are not sufficientlyprotective because of the presence of multiple contaminants at asite or multiple pathways of exposure."

Therefore, preliminary remediation goals pertaining tolandfill surface materials, seeps, the settling basin and streamsediments should be set at 10~6 for carcinogenic contaminants.

One set of ground water remediation goals is to beestablished for ground water contaminants within the area ofattainment (rather than two tiers of remediation goals, one foron-site and one for off-site ground water). For subsurface soilat cells A and B/C and for ground water within the area ofattainment, preliminary remediation goals will generally be setat the MCLs. However, when ARARs are not available or are notsufficiently protective because of the presence of multiplecontaminants at a site or multiple pathways of exposure, risk-based cleanup levels shall be used for carcinogenic contaminants(i.e., the preliminary remediation goal shall be set at 10~6),and a cumulative hazard index of unity will determine contaminantcleanup levels for noncarcinogenic contaminants.

Page 2-3, first paragraph: It is stated, "No cleanup goalsare proposed for subsurface soil outside Cell B/C or surfacewater from the Unnamed Creek, because neither of theseenvironmental media are postulated to pose a significant healthrisk. Have potential environmental impacts of the site on thecreek been fully considered? In light of the comment aboveregarding section 1.5.2 of the Report, monitoring (biological andchemical) for stream recovery should be conducted as part of theremedial action.

Since it is postulated that no significant health risk isposed by subsurface soil outside cells B/C (based on modeling andrisk calculations involving analytical results for a limitednumber of subsurface soils, excluding cells B/C), provide therationale for developing remedial alternatives that address thesemedia (e.g., the containment technologies). Note thatcontaminants such as benzo(a)pyrene have been detected in groundwater at levels which present significant human health risk;however, benzo(a)pyrene was not detected in subsurface samplesobtained from cells B/C (borings in waste ITW-7 and ITW-8). Aresubsurface soils/wastes outside of cells B/C a potential source

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of certain ground water contaminants of concern? Have otherground water contaminants of concern (e.g., manganese andcadmium) been detected at higher levels in subsurface soilsoutside cells B/C (as opposed to within cells B/C)? Has it beendetermined whether other landfill debris have become contaminatedas a result of depositing the PVC sludge materials in cells B/C?Will these other wastes be remediated as part of the cell B/Ccleanup?

Second sentence: "Key constituents listed for each mediumof concern...."

Page 2-3, third paragraph: Does the preliminary remediationgoal for cells A and B/C apply only to soils underlaying the PVCsludge material? If so, please specify remediation goals for thePVC sludge also. If the preliminary remediation goal proposed inTable 2-2 is intended to apply to the PVC sludge (in addition toany commingled and underlying soils), what is the justificationfor using the Summers model to determine cleanup levels for thismaterial? Since the physicochemical properties of site soilsdiffer substantially from those of the waste material itself, itis suggested that separate cleanup goals be set for each. Theidentification and screening of remediation technologies shouldalso take into account the different properties of the PVC sludgeand potentially contaminated natural soils; it may be appropriateto select different remediation technologies for the sludgematerial, and for potentially contaminated underlying soils.

The list of contaminants found in the cell B/C area (boringsITW-7 and ITW-8) is presented in Table 6-10 of the RI Report.Why is no cleanup level proposed for contaminants other thanvinyl chloride in Table 2-2 of the preliminary FS Report?

Section 2.2.3, Cost: The cost analysis in feasibilitystudies at this stage of screening involves a comparison betweentwo or more technologies that accomplish the same function but ata different cost. The report should follow this format.Although a detailed cost analysis is not required, it isimportant, where competing technologies exist, to note the costdifference and screen out the more costly technology. Pleasepresent relative capital and O&M costs for the process options inTable 2-5.

Page 2-8, Soil Cap, Initial Screening, last sentence: Thequalifier, "when used alone," is included in the initialscreening. Is this appropriate? Where is this technologyotherwise retained?

Page 2-9, Physical Stabilizer: The description states thata physical stabilizer will "form an impermeable layer." Theinitial screening states that this technology "has the advantage

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of low permeability." The composite formed cannot be impermeableand have low permeability; the description should state "form alow permeability layer."

Page 2-9, Clay Cap, Description: What design criteria, orremediation objectives were used to develop cap specifications?

Section 2.3.1.4, Disposal: Insufficient information isprovided regarding Land Disposal Restrictions. According toLDRs, treatment standards for specific LDR wastes are based onbest demonstrated available technology (BDAT), using eitherconcentration-based performance standards or chemical-specificmethods of treatment. If a treatment standard for an LDR wastecannot be met, a treatability variance may apply if the waste issignificantly different from the waste used by EPA to set thetreatment standard. CERCLA soil and debris may be handledthrough the treatability variance process. Moreover, EPA hasdeveloped treatability variance guidance specifically for soiland debris treatment ("Superfund LDR Guide #6A (2nd Edition)»Obtaining a Soil and Debris Treatability Variance for RemedialActions," Superfund Publication: 9347.3-06FS, September 1990).

Page 2-14, Clay Cap, Initial Screening: It is not clear whythe option of a clay cap is eliminated here, yet retained inscreening reported on page 2-9. The analysis is inadequatebecause clay caps are generally effective and implementable atlandfills. Effectiveness is determined by the degree to whichhuman health and the environment are protected. The degree towhich clay caps are effective depends on construction parameters(type and thickness of clay, compaction, grading, erosion controlfeatures, surface vegetation, etc.) and maintenance. The use ofa clay cap at a particular site may be a function of cost, whichis reflective of availability of an appropriate borrow source andother construction costs. If there is a specific reason why, forthe "medium" being considered, clay is inappropriate as a cappingmaterial, it should be stated. Otherwise, clay capping remains aviable alternative. Cost comparisons of clay with asphalt orother capping materials is appropriate, if these other materialsmeet the criteria of effectiveness and implementability.

Page 2-15, Multilayer Cap, Initial Screening: The initialscreening is not consistent with earlier screening of thistechnology (page 2-10 of the Report). Please include all of thefactors which are being considered in the initial screening oftechnologies.

Page 2-15, second bullet: The discussion of forcedextraction mentions a chamber. Please explain the chamber thatis discussed here.

Page 2-16, fifth line: What types of fugitive emissions are

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considered? Gas? Dust? Aerosol?

Page 2-16, on-Site consolidation. Description: LDR criteriashould be incorporated into the ARARs section. They are action-specific regulations which must be evaluated for many of thedisposal options.

Page 2-16, On-Site Consolidation, Initial Screening: Duringscreening, this option is eliminated based on LDRs and testingthat has not been completed. This is inappropriate. Disposaltechnologies may be suitable even if testing shows that wastesare RCRA characteristic wastes (see comment regarding section2.3.1.4). There are many cases of variances that have been orare being applied, especially at CERCLA sites. Please rescreenthis technology based on these considerations.

Page 2-17, Off-Site Disposal, Initial Screening: Please seethe previous comment.

Section 2.3.2.6, Treatment, fourth line: Please change"remediation" action to "remedial" action.

Page 2-17, In Situ Bioremediation, Description: The word"biomass" is too general, when what is meant is soil microbes ora consortia of soil microorganisms (or possibly just soilorganisms). This applies to the use of the word throughout thedocument.

Page 2-17, In situ Bioremediation, Initial Screening:Insufficient information is provided to screen in situbioremediation. The author apparently has assumed an aerobicpathway, and that conditions are nutrient-limited (previousparagraph). Bioremediation is not necessarily limited by lowconcentrations of contaminants; in some cases, low concentrationsof contaminants are required to effectively conductbioremediation. The "primary contaminants of concern" are notstated explicitly in this section so it is difficult to determinetheir treatability with respect to bioremediation. The otheroptions that are used for comparison in screening must bespecified before the technology can be eliminated fromconsideration. Additional information is needed to support theconclusion presented here that bioremediation is not effectivefor the degradation of the primary contaminants of concern.

Page 2-18, Ex Situ Bioremediation, Initial Screening: Seethe comment above regarding in situ bioremediation.

Page 2-18, Land Treatment, Initial Screening: See thecomment above regarding in situ bioremediation.

Page 2-18, Soil Washing (Ex Situ), Description: The test

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states that soil washing is applicable to fine silts, clays, andsoil organic matter. How applicable is it considering thecolloid-forming properties of these kinds of materials when theyinteract with water? Is the technology more appropriate forsoils that are primarily sandy, with a small fraction of siltsand clays? What is attrition scrubbing? Please clarify thissection.

Page 2-19, soil Flushing, Initial Screening: According tothe text, in situ soil flushing requires a horizontal andvertical layer. What kind of layers are these? Are theycharacterized by low permeability?

Page 2-20, Soil Aeration, Initial Screening: The screeningout of soil aeration based on low volatility of some contaminantscontradicts the initial screening of a similar technology, SVE(described on the same page), which also depends on removal ofcontaminants that are volatile. What is the volatility of thecontaminants that are to be addressed? Is this technology onlysuitable for some of these contaminants while others requirealternate methods? Please provide an explanation. While airemissions produced by the method may require control measures,these are available and implementable through the use ofenclosures. With this in mind, please reevaluate thistechnology.

Page 2-21, In Situ Heating, Description: In situ heatingappears to be a combination of distinct technologies as presentedhere. Please distinguish between the methods of hot airinjection, which is generally not cost-effective due to the lowheat-carrying capacity of air; radio frequency treatment, inwhich specific target analytes are mobilized and/or destroyedthrough the generation of medium wave or microwave radiofrequencies in the soils; and in situ vitrification, in which anelectric current is made to pass between electrodes placed in thesoil.

Page 2-21, Polymerization, Initial Screening: Mustpolymerization be implemented in situ? If so, then how does "avery controlled environment (reactor)" fit in? What proposedremedial technology is eliminated, in situ polymerization orpolymerization generally?

Page 2-22, Chemical Dachlorination, Initial Screening: Whatis meant by the statement, "There is also not enough data toindicate that this technology can remediate the site-specificcontaminants?" Are treatability studies required?

Page 2-22, Cement-Based Processes, Description: What ismeant by a "stronger type of waste/concrete composite?" Pleaseexplain the statement, "The containment for leaching is produced

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by microencapsulation in the concrete matrix."Page 2-22, Cement-Based Processes, Initial Screening:

According to the Report, off-site treatment using this technologyis not cost-effective. Please provide the cost analysis for thistechnology and competing technologies.

Page 2-24, In Situ Vitrification, Initial Screening: Thelast two sentences are ambiguous. The purpose of this portion ofthe FS is to screen out alternatives or retain them for furtherinvestigation. Please revise these statements.

Page 2-24, in Situ Solidification, Description: It is notpossible to discern what technology is being described. Pleaseprovide a better description of this alternative, or remove it.

Page 2-25, Wet Air Oxidation, Initial Screening: Pleasemention the type of thermal treatment systems that are beingretained for further analyses when discussing cost-effectiveness.

Page 2-25, Low Temperature Thermal Desorption, Description:Please use a consistent set of units (degrees Fahrenheit is usedhere and on pages 2-26 through 2-29; on the previous page,degrees Celsius is used.)

Page 2-26, Infrared Thermal Treatment, Initial Screening:Please include the cost-analysis of process options. Note that apermit is not required for on-site CERCLA response actions(although the substantive requirements of the permit must bemet). Please rescreen this alternative.

Page 2-27, Fluidized Bed Incinerator, Initial Screening:Circulating fluidized bed incinerators have been successfullydemonstrated and used in full-scale remediation. Why is thistechnology "not considered implementable?" Please see thecomment above regarding permitting requirements and costanalysis.

Page 2-30, Vapor Treatment: Vapor treatment is a criticallink in any vapor collection/extraction/treatment system. Noanalysis of different methods of vapor treatment or theirapplicability to the specific chemicals requiring treatment isprovided. Please identify and screen the different vaportreatment methods.

Page 2-31, Off-Gas Treatment: How do vapor treatment andoff-gas treatment differ? Please explain the difference (andidentify and screen different treatment options) or combine thetwo into one section.

Section 2.3.3.3, Containment: What is meant by "potentially

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horizontal?"

Page 2-33, first bullet: Cost seems to be the only reasonfor retaining the soil-bentonite slurry wall among the verticalbarrier options.

Page 2-33, second bullet: In the second sentence, statethat cement is added to "reduce the permeability," rather than"to increase the impermeability."

Page 2-33, Vertical Barriers, Initial Screening: Theanalysis of slurry walls has not addressed the chemicalcompatibility issues. Please explain.

Page 2-34, Horizontal Barriers, Initial Screening: It isnot clear from the description of bedrock pressure grouting whythis is a technology that is retained for further consideration.

Page 2-35, first paragraph: Is a leachate extraction systemdistinct from a ground water extraction system? Is there aseparate surface water collection system? How do these relate toa leachate collection system, and how do they each differ? Manysystems are mentioned in this paragraph. Please clarify.

Page 2-35, Well Points, Description, first line: Wells ona well point system may be driven, jetted, or augered. Later, inthe same paragraph, a capacity statement is made along withstatements regarding usage. Please cite references.

Page 2-35, Well Points, Initial Screening: The radius ofinfluence and the applicability for ground water remediation arefunctions of well point system design, the nature of thecontaminants and aquifer characteristics. Please explain howdesign considerations and contaminant characteristics were takeninto account in this analysis.

Page 2-36, Groundwater Interception Trench/Drain,Description: It is stated that "[s]ubsurface drains do not havea large capacity. Thus it is difficult to obtain a large radiusof influence." Capacity is a function of design, as is theradius of influence. The radius of influence is comparable, ifnot greater than, other technologies such as wells. Pleasereview/revise.

Page 2-38, Groundwater Recharge by seepage Basin, initialScreening: Has an off-site location (one which would not resultin generation of more leachate) been considered? Are there anycosts of disposal if excavated soils are consolidated at thelandfill? Please review.

Page 2-38, Groundvater Recharg* by French Drains,

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Description: Siltation of french drains is a function of designand installation. Please clarify the statement.

Page 2-38, Groundwater Recharge by French Drains, initialScreening: Disposal costs for excavated soil are considered.Has disposal of these soils at the landfill been considered?

Page 2-39, Surface Water (NPDES) Discharge, InitialScreening: Treatment standards for a surface water dischargewould likely be more stringent than drinking water standards.Ambient water quality criteria may be applicable.

Page 2-39, Publicly Owned Treatment Works, Description: Thedefinition of POTW should be placed at the first reference (thirdline on page 2-38).

Page 2-40, Well Injection, Description, last line: Arethese well points or wells?

Page 2-41, first bullet: Please cite the reference on"conventional reactor basin." It appears to incorporatedifferent processes for treatment, including (perhaps) aerobicbiodegradation, air flotation, phase separation, flocculation,settling and clarification. A particular design appears to beunder consideration, since recycle (recirculation) is mentioned.

Page 2-41, second bullet: Acclimation and growth may be onsynthetic or natural media. Historically, natural media has beenmore widely used. Please clarify.

Page 2-42, first bullet: The RBC is a rotating biologicalcontactor, not contractor.

Page 2-42, second bullet: The report states, "Thetechnology is relatively new and commercially not available."The PACT process, patented by E.I. duPont, has been in existenceand commercially available for many years. It treats a varietyof organic compounds, organometallic complexes, etc..

Page 2-42, Initial Screening: The analysis of biologicaloptions is very limited; the technology may be prematurelyscreened from further consideration. Many options werepresented; if they are all actually being considered, each oneshould be screened separately. Also, it is asserted that lowconcentrations of site contaminants make biodegradationineffective. There are many sites where biodegradation isoccurring and/or being encouraged where the concentrations ofcontaminants are similar or at lower concentrations than at thissite. Please cite the reference for identification of bestavailable technology for treatment of site-specific contaminantsand state what BAT is.

Page 2-43, Wet Air Oxidation: Wet air oxidation is not aprocess that applies to contaminants dissolved or suspended inground water, except when used in conjunctions with anothertechnology, such as the PACT process or activated carbonadsorption. WAO is used in such a combination to oxidizeorganics and regenerate the carbon. Although initially theprocess is capital intensive, such systems can be cost-effectiveon large capacity systems where carbon usage would be extensive.WAO should not be suggested for ground water treatment except insuch a capacity where it has been used effectively.

Page 2-44, sixth line: Pretreatment for iron or manganesemay or may not be necessary, depending on concentrations. Pleaseclarify.

Page 2-44, Steam Stripping: Does steam stripping have acommon application in ground water remediation, or is it atechnology that is in the experimental or developmental phase forsoil vapor and ground water treatment?

Page 2-45, Sedimentation, Description: The first sentenceis unclear.

Page 2-46, Filtration, Description: Sand filters are onlyone type of filter. Many others exist. Please explain theselection of sand filters or incorporate other types of filtersinto the discussion.

Page 2-46, Ion Exchange, initial Screening: The test statesthat "the major contaminants of interest at the site areorganics." This is the first place such a statement has beenmade. How does it correlate with data presented in earliersections? Do metals play a significant role in site-relatedrisk, and difficulties for some treatment technologies?

Page 2-47, Liquid/Liquid Extraction: Please cite thereference on liquid-liquid extraction and the use of chelatingagents. They are not the same. Liquid-liquid extraction dependson preferentially greater solubility of a contaminant for anorganic solvent (such as methylene chloride, or other relativelynon-water-soluble solvent). Chelation depends on preferentialadsorption/chelation phenomena wherein a metal ion forms covalentbonds with a dissolved molecule (chelating agent).

Page 2-48, UV/Peroxide/Ozone Oxidation, Description:Cyanides are mentioned. Are cyanides a problem at the site? Ifthey are not, why are they mentioned here?

Page 2-48, Chemical Coagulation, Description: How isemulsification related to flocculation and coagulation?

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Page 2-49, Chemical Coagulation, Initial Screening: Foulingof equipment is mentioned. What kind of equipment? Airstripping equipment or flocculation equipment?

Page 2-49, Electrolysis, Description: The description ofelectrolysis indicates an oxidation/reduction reaction. Is thiscorrect or are dissociation and/or chemical decompositioninvolved?

Page 2-49, Electrolysis, Initial Screening: Which site-specific constituents may be treated by electrolysis? Pleaseprovide a cost analysis for this technology and its competingtechnologies.

Page 2-50, Reduction, Description: This section is titled"Reduction." However, the first line of the description mentionsan oxidation-reduction reaction, and the following sentencementions metallic hydroxide sludge (indicating oxidation). Whichchemical reaction is being suggested? Please clarify the text.

Page 2-50, Reduction, Initial Screening: Please cite thereference of the information regarding cost-effectiveness andrefer to the specific treatment option that is more cost-effective .

Page 2-50, Chemical Deehlorination, Description: What ismeant by the statement, "This can also be achieved by reducingthe oxidation and reduction potential?"

Page 2-51, Off-Gas Treatment, Description: What inorganicgases are being referred to? Control of vapor phase contaminantsmay be necessary to comply with air pathway ARARs such as theNational Emission Standard for Vinyl Chloride (40 CFR 61, SubpartF) and State toxic/hazardous air pollution regulations, and toprovide adequate protection of human health and the environment.No analysis of different methods of vapor treatment or theirapplicability to the specific chemicals requiring treatment isprovided. Control technologies for vapor phase contaminantsinclude carbon adsorption systems, condensation, thermal andcatalytic oxidation, wet scrubbing, and oxidation by internalcombustion engines, as well as emerging technologies such as UVphotolysis. Note that carbon adsorption units may noteffectively control certain emissions (e.g., vinyl chlorideemissions). Please identify and screen the different vaportreatment methods in view of these considerations.

Page 2-52, Point-of-Use Treatment, Description: Rewrite tomake the following points: (1) residents are using ground waterand (2) some ground water which is currently being used byresidents is contaminated and requires treatment. How effectiveare carbon adsorption units in removing the contaminants of

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concern? Please provide references. Identify other point-of-useoptions for screening.

Page 2-53, New Community Well, Description: What is meantby "affected area?"

Page 2-53, On-Site Water Supply, Description: The title ofthis section should apparently be "Off-Site Water Supply." Howis off-site defined in this context?

Page 2-53, On-Site Water Supply, Initial Screening: Whatother options were compared for cost-effectiveness?

Page 2-55, Institutional Actions, Initial Screening: Airpollution monitoring cannot be so easily eliminated since certainremediation processes may require it (e.g., mobile incinerators,soil vapor extraction, etc.). Note also that 56 Federal Register51020 (October 9, 1991) outlines operating criteria, includingperimeter monitoring, for municipal solid waste landfills. Havecurrent and future air guidelines been considered in thescreening? Please elaborate.

Page 2-56, fifth line: How do impermeable interceptionsystems "provide conduits to the surface?"

Page 2-58, Active Collection Systems, Initial Screening:Please provide or cite a reference for the calculations.

Section 2.3.5.4, Treatment, first paragraph: The words"generally" and "only" contradict each other in the secondsentence.

Page 2-59, Carbon Adsorption, Initial Screening: Thescreening of this technology did not consider site-specificcontaminants. Vinyl chloride has a low affinity for activatedcarbon and will quickly break through carbon. Large capacitycarbon beds and/or a high replenishment rate may be required toeffect removal of this contaminant from the vapor stream. Pleasesee the comment above regarding page 2-51.

Page 2-60, Open Flaring, Initial Screening: The selectionof enclosed ground flaring depends on the contaminants present.Was this technology evaluated with regard to the site-specificcontaminants, and was it evaluated for effectiveness andimplementability? Also, please cite a reference for the BACTevaluation.

Section 3.0, Development of Remedial Action Alternatives:Please modify this section as necessary, in accordance with thecomments pertaining to section 2.

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Page 3-1, first paragraph: What does "sitewide" mean andhow is it contradistinguished from "groundwater" with respect totreatment alternatives?

Section 3.2.2, Alternative 2, second paragraph: A securityfence will also require locked gates for access, possibly barbedwire, and scheduled maintenance. Please clarify the text.

Third paragraph: Revegetation may require fertilization,watering and maintenance (e.g., grass cutting, pest control,etc.). Please clarify the text.

Page 3-3, first paragraph: Specifically, what deedrestrictions are suggested? Please define the "area of thelandfill."

Page 3-3, second paragraph: Briefly describe the existingand proposed expanded monitoring well networks, the monitoringschedule, and the period of performance of monitoring. Thisapplies to all monitoring suggested in other locations in theReport.

Section 3.2.3, Alternative 3, first and second paragraphs,and Figure 3-11: The proposed cap requires review. As shown, itwould not be cost-effective and may not satisfy the remediationobjective. To achieve the drainage as shown on Figure 3-11,large quantities of fill would need to be imported to the site.Normally, this requirement is minimized by grading and using, tothe extent possible, existing contours. What design criteria (orremediation objectives) were used to develop the specificationsfor the clay layer? Further analysis (see cost evaluationcomments below) indicates other flaws in the proposed cap. Adiversion structure may be required.

Page 3-4, second paragraph: Does placement of a cap requireclearing and grubbing, and is any other surface preparationnecessary? Also, a HOPE liner is only one of a number of linersavailable. Why was this one chosen? What are the others andwhat are their advantages and disadvantages?

Page 3-4, third paragraph: Have the "additional sources"been identified? How are they being taken into consideration forthe various other alternatives? Are there ownership issues thatneed to be addressed, both in terms of access (for wastes locatedon off-site properties) and PRP identification? Please indicatehow these issues will be handled in the feasibility study.

Page 3-4, fourth paragraph: Please indicate the perchedwater zone(s).on a figure. The use of "may" and "would"introduces ambiguity into an alternative. The slurry wall iseither being considered or it is not, based on screening

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criteria. Please clarify the text indicating whether a slurrywall is a component of Alternative 3, and modify Figure 3-2 ifnecessary. Please note: a slurry wall to a depth of 115 feetneeds to be screened with respect to technical implementability.

Page 3-6, second paragraph: Please see the comment aboveregarding implementability. What is meant by the statement, "Theperimeter wall will be designed to minimize the hydraulicconnection between the wall and bedrock?" Also, how would the"most competent bedrock" be determined? Are there problemsassociated with keying a slurry wall into bedrock?

Page 3-6, fourth paragraph: A "minimal groundwatertreatment system" is proposed without explanation regarding itspurpose and how this purpose differs from that of other groundwater treatment systems. Please explain.

Page 3-7, first paragraph: The location of ground waterextraction wells for Alternative 5 is shown in Figure 3-4 (not 3-5).

Section 3.2.7, second paragraph: The reinjectionalternative proposes 24 pumping and 24 injection wells. How dothese correlate with the 40 extraction wells proposed in previousalternatives? The 40 were reportedly necessary to produce thesame flow rate of 100 gpm. Also, there is no discussion of theeffects of gradient, placement of wells, and the degree ofcharacterization of the stratigraphy and hydrogeology necessaryto effectively implement this alternative without spreadingcontaminants. Please clarify.

It is stated that an injection permit will be required toreinject treated ground water. Section 300.300(e) of the NCPstates: "No federal, state, or local permits are required foron-site response actions conducted pursuant to CERCLA.... Theterm "on-site" means the areal extent of contamination and allsuitable areas in very close proximity to the contaminationnecessary for implementation of the response action." Theinjection of treated ground water must, however, meet thesubstantive requirements of the SDWA Underground InjectionControl Program.

Section 3.2.8, Alternative 8: Please specify a time framefor remediation of cells A and B/C material using SVE. What is awaste pore? Would temperature control of the vapor stream benecessary on such a system? Is the suggested method appropriatefor site-specific contaminants? Please specify the "contaminantsof concern." A clay cap is suggested for implementation afterSVE is complete. Would a cap installed prior to SVE make thesystem more effective? What methods will be used for treatmentof vapors?

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Page 3-10, third paragraph: What methods are contemplatedfor treatment of vapors?

Pag* 3-11, first paragraph: What is meant by thisstatement: "A control system is used to relocate the temperatureand desorption/combustion characteristics inside the kiln?" Is"maintain" a better word than "relocate?"

Pag* 3-13, top: Please see the comments above regarding thelimitations of vapor phase carbon adsorption system for removalof vinyl chloride from the vapor phase.

Section 4.0, Preliminary Screening of Alternatives: The FSprocess (SARA Section 121) is to emphasize the development ofremedial alternatives that provide permanent solutions tocontamination problems, and long-term effectiveness.Furthermore, EPA expects to use treatment to address areascontaminated with high concentrations of toxic or highly mobilecontaminants (Section 300.430 of the NCP). However, only two ofthe alternatives that are selected for detailed analysis includetreatment of hot spots. Additional treatment technologies shouldbe developed for screening and carried over to the detailedanalysis of alternatives in the event that soil vapor extractionand low temperature thermal desorption are shown to be infeasibleas a result of the ongoing treatability studies. As noted above,it may be expedient to develop different remediation technologiesfor PVC sludge material, and for adjacent contaminated soils/debris.

Page 4-3, third bullet: Please see comments above regardingon-site permitting requirements.

Page 4-14, TSD Services: It is not clear that TSDrequirements for Alternative 6 are more extensive than thoserequirements for Alternatives 5 and 7.

Page 4-15, Equipment/Specialists: The installation of along sewer discharge line is not an activity that requiresequipment or expertise that is not readily available. It seemsunreasonable to assign a score for this criterion to Alternative6 that is midway between the score assigned to Alternative 5 andAlternative 4 (which calls for installation of a slurry wall andbedrock grouting).

Page 4-25, cost Evaluation: It is stated in the ExecutiveSummary that preliminary present-worth cost estimates wereprepared with an accuracy of +50% to -30%. Here it is statedthat the accuracy of the cost estimates range from +100% to -50%.Please clarify this discrepancy.

Section 4.4, Effect of Preliminary Remedial Action Goals on

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Alternatives: Please provide a separate cleanup goal for PVCsludge, and for surrounding soils.

Alternative 2: Institutional Actions1. Table A (Appendix C) indicates that eight monitoring

wells are to be installed. Are these wells for groundwater monitoring or soil-gas monitoring? If they arefor ground water monitoring, then the installation ofthe soil-gas monitoring system, as indicated in section3.2.2 (page 3-2) is required in the cost estimate.

2. The soil-gas monitoring should also be added to Table B(Appendix C) unless it is considered under the on-sitemonitoring line item.

Alternative 3: Landfill Capping

l. Section 3.2.3 indicates that runoff/runon controldevices would be used for this alternative. Figure 3-2illustrates the use of cap lateral drains that outfallinto a drainage ditch encompassing the clay cap. Basedon the existing topography shown on Figure 1-1,construction of the drainage ditch as proposed mayprove to be difficult, specifically in the area alongthe northern portion of the western property boundary.In addition, the outfall from the lateral drains intothe open drainage ditch may not be a preferred methodof controlling drainage.

2. The construction of the perimeter drainage ditch doesnot appear to be included in Table E (Appendix C) ofthe cost analysis.

3. Costs are given in Table E for trenching/backfilling,pipe bedding and a 36" diameter drainage pipe. Thelocation of this 36" diameter drainage pipe is notspecified on Figure 3-2. If this pipe is the surfacewater discharge pipe from the collection basin to theunnamed creek, then the 6,000 linear feet of the pipespecified is not correct.

4. The rip-rap specified in Table E is not indicated onFigure 3-2.

5. The lump sum cost given in Table E for the collectionbasin may be too low.

6. Section 3.2.3 indicates that a partial slurry wall may

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also be constructed under this alternative. Shouldthis be included in the cost estimate?

7. It is difficult to evaluate the estimated cost of thegas collection system without a layout.

Alternative 4: Capping/Slurry Wall/Grouting/Pump and Treat

1. The cost of the ground water treatment alternative iscalculated in Table J (Appendix C). Table J wascomputed assuming water would be treated at 100 gpm.Under this alternative, only 30 gpm is proposed to bepumped and treated using 23 0.5 hp pumps to extract thewater. The capital cost used for this alternative fortreating the ground water is based on a percentage ofthe total capital cost computed in Table J toaccommodate the lower volume of water to be treated.This does not appear to be a reasonable method forcalculating the treatment cost of a smaller volume ofground water. (Note that the same percentage (43%)used for capital costs was also used when computing theoperation and maintenance (O&M) costs.)

2. Table C-3A uses an incorrect value for the cost ofinstitutional actions.

3. The quantity for the NPDES discharge pipe used in TableC-3A appears excessive. Also, no size or type of pipewas given to support the cost shown.

4. Two other unit costs appear to be excessive in Table c-3A: the unit cost for grouting and the unit cost forthe submersible well pumps.

5. Based on the information provided, it is difficult toevaluate quantities and unit costs of items listed inTable J for the pretreatment system.

Alternative 5: Capping/Pump and Treat/MPDES Discharge1. Comment #1 for Alternative 4 applies; however, 78% of

the total treatment capital and O&M costs do totreatment of only 70 gpm is used.

2. Comment #3 and part of comment #4 (unit cost for wellpumps) for Alternative 4 also apply to thisalternative.

Alternative 6: Capping/Pump and Treat/POTW Discharge

1. Section 3.2.6 is confusing with regard to the planned

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facility receiving the discharge. A seven miledischarge line would imply the outfall is located atthe Perryville POTW. However, the cost analysisindicates a ten mile outfall to the Seneca Point POTW.

2. Since the planned pumping rate is 70 gpm, the samepercentage (78%) of total treatment capital and o&Mcosts for ground water is used for this alternative asis used for Alternative 5. Please see comment aboveregarding Alternative 5.

3. Why is the proposed volume of on-site pretreatment ofthe ground water discharged to the POTW less than theproposed volume of water discharged to the unnamedcreek and the injection wells?

4. There is an error in the institutional cost shown inTable C-5A.

5. The unit cost for the submersible well pumps is thesame as in previous alternatives.

Alternative 7: capping/Pump and Treat/Injection Wells

1. The unit cost for the submersible well pumps is thesame as in previous alternatives.

Alternative 8: Capping/Pump and Treat/SVE

1. All comments pertaining to Alternative 5 also apply tothis alternative.

Alternative 9: Capping/Pump and Treat/Thermal Desorption

1. All comments pertaining to Alternative 5 apply.

2. Section 3.2.9 indicates that the excavated materialsare to be stored on a containment pad. No costs weregiven for the containment pad. Please add theassociated costs.

3. The total capital cost in Table N was incorrectlytransferred to Table C-8A.

4. Section 3.2.9 notes that off-site material may berequired. Please include any additional material costsin the cost estimate.

5. O&M costs are not computed for the thermal desorption.Is this because six months' operation costs areincluded in capital costs?

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Alternative 10: Capping/Pump and Treat/On-site Incineration

1. All comments pertaining to Alternative 5 apply.

2. Comment #2 for Alternative 9 applies.

3. O&M costs were not computed.

4. Table C-9A lists an on-site ash disposal facility whichshould include a storage facility for the ash and theon-site solid waste management units. Please evaluate.

Alternative 11: Capping/Pump and Treat/Off-site Incineration

1. The study does not indicate where the off-siteincineration facility is located. The cost analysisassumes a distance of 2.000 miles at 22 cubic yards perload and a unit cost of only $10. These values appearto be too low.

2. The quantity used for off-site incineration in Table C-10A appears low. The unit cost for this line item isquestionable.

3. Why was only 2% engineering and design cost assumed inTable C-lOA? This appears to be low.

Table 2-2: What parameters (e.g., Koc for vinyl chloride)were used to determine the cleanup level? As noted in thecomments on the RI Report, Koc - 134 does not appear to beappropriate.

Table 2-3, page 1: The point of departure for settingcleanup levels for carcinogens when ARARs are not available isthe 10~6 risk level. The use of the 10~4 risk level is notappropriate for setting cleanup levels. (Please see the commentabove regarding preliminary remediation goals.) What is theaggregate risk associated with the proposed cleanup levels (MCL,if available; otherwise 10~6 risk-based level)? What is theaggregate risk for treated ground water which meets the proposedcleanup goals (including risk associated with ground watercontaminants which are not addressed by the proposed cleanupgoals)?

Table 2-3, page 2: What is the aggregate hazard indexassociated with the proposed cleanup levels for the contaminantslisted here (MCLs, for those contaminants for which an MCL isavailable; otherwise, health-based cleanup level)? What is theaggregate HI for treated ground water which meets the proposedcleanup goals (including risk associated with ground water

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contaminants which are not addressed by the proposed cleanupgoals)? Is the aggregate HI based on these cleanup goals lessthan unity?

Table 2-4: Please see the comments pertaining to Table 2-3and reevaluate the proposed risk-based cleanup level.

Appendix A: Please review and update ARARs and TBCs inaccordance with the earlier comments and those that follow. Alsoadd one table for location-specific ARARs and another for action-specific ARARs. (Table A-3 includes some of these ARARs and canbe deleted to avoid redundancy. )

Table A-l:

1 . Footnote the proposed date (i.e., as of year ___ ) .

2. Please include 1,2-dichloroethane on the list forchemical-specific ARARs.

3. Include the State (or Federal) ambient water qualitystandards for fresh water acute and chronic exposure.

4 . Include the interim RCRA Corrective Actions standardsand interim lead guidance referenced above.

5. The MCL for lead is currently 50 /ig/1 and the finalMCLG for lead is 0 ng/1. Note that the MCL for leadwill be withdrawn in December 1992 (when an actionlevel will be established for lead) . Please see theattached memorandum regarding cleanup levels for leadin ground water (June 21, 1990) , and include a groundwater cleanup level of 15 pg/1 for lead as a TBC.

6. Delete the word "proposed" after the MCLGs for benzeneand tr ichloroethene .

7. The detection limits associated with some analyticalmethods (e.g., Method 524.2) are not included in thelast column.

8. Please add reference dose levels and risk levels (forcarcinogens) for all of the contaminants identified inthis table.

9. Add "/State" after "Federal" in the column headings forpotential ARARs.

Table A-2: Chemical-specific ARARs, Requirement II: MCLsare relevant and appropriate (not applicable) requirements at theWoodlawn Landfill site for the range of alternatives presented in

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the Report.

To Be Considered Materials, Requirement IV: Emissionstandards are established for hazardous waste that contain atleast 10 ppm organics.

To Be Considered Materials: Please add the following: EPAHealth Advisories (EPA Office of Drinking Water); "EPA Policy forGround Water Remediation at Superfund Sites," OSWER Directive9355.4-03; "Control of Air Emissions from Air Strippers atSuperfund Ground Water Sites," June 1989, OSWER Directive9355.0-28 .

Table A-3, page 1, first citation: It is stated in thecomment section that the Woodlawn Landfill site contains RCRA-listed wastes. Please explain.

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State CommentsWoodlawn Landfill RI/FS Report

March 1992Vol. I-II and Preliminary FS

Cecil County, Maryland

RI REPORTSpecific Comments

Page / §

ES-1 / 3Reference to the liquid discharge from the transfer stationshould be clarified. It should be indicated that thedischarge occurred in the past and is not currently a"source". The source potential of the soils associated withthe former discharge are being evaluated at this time.ES-3 / Phase IIThe authors should make a greater effort to indicate that theconclusions, or observations, which are presented here,represent the PRP's understanding of the site at theconclusion of the Phase II activities. Bullet three, at facevalue, may be misleading to the average citizen reading thisdocument.

ES-5 / Phase III Bullet 5Reference is made to the synthetic model of the aquifer undera future use scenario. The phrase "anticipated future use"should be modified to indicated that the future use scenariowas very limited in scope. The model did not include allpotential water supplies, but rather only those that wereknown to be pending at the time of the modeling.

ES-7 / Phase IV, § 2"The sources of contamination from the Site include:" shouldbe modified to indicate that these were the identified orsuspected sources of contamination emanating from the site atthe conclusion of the Phase IV activities. Further, it shouldbe clarified that while the former septic system's effluentmay have impacted local groundwater, the system has beenmodified and the effluent from the system is no longer acontinuing source or potential source as is the case withCells A/B/C which may pose a continuing source.

ES-7 / 3 "Wastes and contamination..."Since the general public is most likely to read this portionof the document, it should be indicated that the observationswhich are presented represent a glimpse of time correspondingto the conclusion of the Phase IV activities.

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Page / §

6 ES-8 / 2"The potential source areas were identified" should probablybe modified to indicate that general areas representingpotential sources of contamination were identified. Thegeneral scope of an RI is not to identify all specific pointsources of contamination but rather to characterize the site,identifying significant potential sources of contaminationonly as a result of the characterization.

7 ES-8 / 3To which U.S. EPA standards is the author referring?

8 1-2 / 1.2.1-2Is it really appropriate to say, "The Site is hereindesignated..."? Were the boundaries of the Site that clearlydefined in the NPL Listing?

9 2-26/ 2The section has consistently raised the issue of thedegradation of chlorinated hydrocarbons as a significantsource of VC. Perhaps it would be appropriate to include asite specific mass-balance calculation to demonstrate thishypothesis at the site. Field examples, showing the ratios ofprogenitor compound to degradation product(s) , as observed, atother sites would be most useful.

10 2-73/ 5The paragraph appears to be misleading. The first sentenceindicates that for the purpose of the model, the loading rateswere higher for Cells A and B/C. The next two sentencesappear to indicate that VC loading in the general fill may, inactuality, be a more significant source of VC. Obviously thiswill yield a conservative evaluation of the threat posed bythe Cells A and B/C. However, will this approach produce afair evaluation of the threat posed by the VC emanating fromthe general fill? Has the FS adequately addressed thisthreat?

11 5-22/ 2The last sentence is unclear.

12 6-5 / 6.2.1.3-2Sludge was placed in Cell A as early as March 1978.

13 7-1 / 7.1-2In the fourth sentence please explain how the landfillingoperations generated fill material? The last sentence isunclear, "... in areas except where...".

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Page / §

14 7-4 / 7.2.2-3Has the FS fully addressed the significance of this portion ofthe Risk Assessment?

15 7-9 / Last §Possible typo in sixth line (Ar's).

16 7-12 / 7.7.1 Future WorkThe Department recognizes that the groundwater of the Site hasbeen degraded. Further, the Department has approved IT'sPhase III Report which presented a groundwater and contaminantfate model based on VC for the Site. The extent of soilcontamination has been addressed with the completion of theEPA approved soil sampling event conducted in December of1991. With the above in mind, the Department does notrecognize the need for additional RI work in the vicinity ofthe transfer station.

Figures

17 4Since the figure was checked in March 1992 why doesn't itinclude both ITB-6 and TSW-l?

Appendix

18 D / Figure 1ITB-6 and TSW-l should be included on this map.

19 D / Figure 17The contour line (0.15) was incorrectly labeled .015 in twoplaces.

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PRELIMINARY FS REPORT

General Comments

The Department recognizes the need to evaluate availabletechnologies that may be applicable to remedial alternatives thatare under review. Paramount in this evaluation should be theremediation or control of the site and the restoration of the localaquifer to the maximum extent possible. Key to the State'sacceptance of any remedy at the site will be the effectiveness ofthe remedy and the limited use of institutional controls, such asthe currently imposed "Area of Development Restriction" needed toimplement the remedy.

A comparative analysis of remedial technologies which does notminimize the sites impact on the surrounding community isinadequate. The wholesale elimination of technologies, based onperceived costs and implementability, is inappropriate and mayprove to be too restrictive during the later design phase.Similarly, the elimination of technologies based on perceiveddifficulty in obtaining permits is unacceptable since on-siteCERCLA response actions do not require the issuance of a permit,only that the substantive requirements of a permit be met.

Specific CommentsPage / §

1 ES-1 / 3The second to the last sentence in this paragraph should berevised. The septic effluent, discharged through the TransferStation's former system, may have impacted local groundwaterand soils associated with the drain field; however, thisdischarge has been discontinued. Cecil County hasinvestigated the impact on the associated soils and providedthat information to the EPA.

2 l-ll/ 1.3.3.2-2Please explain your interpretation as to the "non-enforceability" of WQC as promulgated by the state ofMaryland.

3 l-ll/ 1.3.3.3Fairbank not Fairbanks. The last sentence should be deleted.

4 1-12/ 1.3.4The unnamed creek adjoining the site has been designated bythe State as a native trout stream and in COMAR 26.08.02.07Eas a public water supply. Both designations carry specificlimitations with regards to NPDES permit requirements.

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Page / §

5 1-12/ 1.3.5COMAR 26.04.07.21 regulates the design and construction oflandfill closure caps. Additionally, COMAR 26.09.01 and .02regulate management of erosion/sediment controls andstormwater both during construction and operation of thefacility.

6 1-13/ 1.4.1-1Both the EPA and the PRPs are conducting independent searchesfor additional PRPs.

7 2-2/ 2.1.1If "goals" equal "objectives" then "elimination" shouldreplace "minimize" in bullet 2.

8 2-3/ 2.1.2-6In the last sentence the author indicates that a cancer riskof 10" target is an acceptable level for on-site groundwaterbecause there are no on-site water supply wells; however, tothe Department's knowledge the Transfer Station continues touse its on-site well for non-potable water. Should this pointbe reconsidered?

9 2-9/ Clay CapCOMAR 26.04.07.2IB specifies that "the closure cap shall bedesigned to minimize infiltration into the landfill and shallbe developed through an engineering analysis of the site",i.e. the EPA's HELP model. To designate the minimum cappingrequirements without a site specific engineering analysis isboth premature and inappropriate.

10 2-10/ Initial ScreeningThe elimination of "multi-layer" or synthetic cappingtechnology for the general fill is perhaps prematureconsidering the above comment and RI comment 10.

11 2-17/ Initial ScreeningThe Department does not view the elimination of a technologyas appropriate if the sole reason for the elimination is alack of data.

12 2-20/ Soil AerationSince the areal extent of both Cells A and B/C is not largeand could be enclosed for excavation and treatment, the airpollution concerns appear to be manageable. Should thistechnology have been eliminated?

13 2-27/ Fluidized Bed IncineratorSee FS General comment.

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Page / §

14 2-36/ Groundwater Interception Trench/DrainIt would seem that the construction of trench/drains wouldprobably be focused on the southern portion of the site wherethe depth of overburden is significantly less than 40 feet.If this is the case, why rule out a technology based on thedifficulty of trench construction to a depth of 40 feet?Could horizontal drilling be utilized to accomplish thetrench/dra in obj ect ive?

15 2-38/ 2.3.3.5Due to the nature of the local aquifer, significant on-sitepumpage may adversely affect the local water suppliesconsidering probable future development. With this in mind,the Department suggests that infiltration galleries or basinsbe given additional consideration.

16 2-55/ 2.3.5.2The construction of a cap and the incidental containment ofseepage gas will create a "new point source" of air emissions.Consequently, air pollution monitoring may be applicable andshould not be eliminated from further consideration becauseCOMAR 26.04.07 does not specifically require it.

17 3-3 / 3.2.2-1The blanket use of institutional controls "... to limit futureuses of the groundwater in the area..." as part of theremedial alternative is unacceptable. If such controls arerequired to protect the public they must be limited, definedand Grafted to protect the rights of the affected propertyowners. The current controls were put into effect solely toprotect the public health until the remediation was in effect.

18 3-3 / 3.2.3In the second sentence does the author mean "... either clay ormulti-layer capping" or a combination of clay and multi-layercapping?

19 3-7 / 3.2.5-2The issuance of an NPDES permit may not be required, dependingon the proposed point of discharge. However, the substantiverequirements of a permit, if issued, would be applicable.

20 3-9 / 3.2.8-3SVE may require a significant period of operation in order toachieve "specified remedial action goals". This alternativeshould be modified so that the capping of the general landfillis not delayed.

21 4-1 to 5-4 / 4.0 to 5.5The Department reserves its comments on these sections pending

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review of IT'S response to the above comments.

Figures

Fig. #

1-1Include significance of the "EASTERN CORRIDOR" stippled areain the legend.3-11The amount of final cover or "prepared sub-base" should be aminimum of 2 feet.

3-12See comment above.

Appendix B

The modeling effort appears to have considered only the currentconditions, i.e. existing residential wells. If this is the case,a future development scenario, one with no developmentrestrictions, must be used to evaluate selected remedies. Thecurrent development restriction area was only implemented as aninterim measure until the selected remedy was in place. (SeeGeneral Comment)

SR3Q6Q23

UNITED STATES ENVIRONMENTAL PROTECTION AGENCYWASHINGTON, 0,C, 20460

SOU0

JLN 211990SUBJECT: Cleanup Level for Lead in Grou/d/$itcrFROM: Henry L. Longest, Director

Office of Emergency andBruce M. Diamond, DirectorJOffice of Waste Programs Enforcement

TO: Patrick K. Tobin, DirectorWaste Management Division, Region ZV

PtmPQSE

This memorandum addresses the issue of a protective cleanuplevel for lead in ground water usable for drinking water, whichis a major concern for several Superfund sites in Region IV.OBJECTIVE

The objective of this memorandum is to recommend a finalcleanup level for lead in ground water usable for drinking waterwhich will meet the CERCLA requirement that all Superfundremedies be protective of human health and the environment.BACKSRQUNp

The current Maximum Contaminant Level (MCL) for lead is 50ppb and was promulgated in 1975 as an interim national primarydrinking water regulation (NPDWR) under the Safe Drinking WaterAct (SDWA). On November 13, 1985, the Agency began the processof revising this standard by proposing a Maximum ContaminantLevel 60*1 (KCLC) as required by the SDWA (50 ZB 46936).

On August 18, 1988 EPA proposed an MCLG for lead at zero andan MCL of 5 ppb (53 £B 31516). Also, since the primary cause oflead-contaminated drinking water is corrosion of lead-bearingpipes in public water supply (PWS) distribution systems and/orhousehold plumbing, the proposed rule would direct PWSs to meettreatment technique requirements and to deliver public educationto reduce and minimize exposures to lead in drinking water.

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These requirements would be triggered when an action levelis exceeded at consumers' taps throughout the water distributionsystem. The Agency proposed an action level of 10 ppb, onaverage, to trigger corrosion control and public education.Another lead action level of 20 ppb, measured at the 95percentile of samples, was proposed as a trigger for publiceducation.

The Agency is considering promulgation of treatmenttechnique requirements which may include additional source watertreatment, lead service connection replacement, and publiceducation if lead concentrations at the tap exceed an actionlevel. Any such technological treatment targets will providesubstantial health protection. A final rule is being worked on,and is scheduled for promulgation in December 1990.DISCUSSION

No cancer potency factor or reference dose has beenpromulgated for lead; therefore, an assessment of protectivelevels of lead in ground water that may be used for drinkingwater purposes will be based on current data. The Agency hasidentified 10 micrograms per deciliter (ug/dl) as a blood leadlevel of concern in young children. Blood lead levels above 10ug/dl are associated with increased risks of potentially adverseeffects on neurological development and diverse physiologicalfunctions.

Attached is available data that support the recommendedfinal cleanup level for lead in drinking water at Superfundsites. This information includes the June 15, 1990. EPA draftfinal report entitled, "Contributions To a Risk Assessment ForLead in Drinking Water" and the June 1986, EPA draft final reportentitled, "Air Quality Criteria for Lead" (Volume ZZZ of ZV, p.11-129). Based on these data, lead levels in drinking water ofIS ppb and lower should correlate to blood lead levels below theconcern level of 10 ug/dl. The Agency estimates that steadyexposure to a water lead concentration of 15 ppb wouldcontribute, at most, 2*3 ug/dl to a child's blood lead. Sourcesof lead other than drinking water (e.g. food, air, soil, dusts)typically contribute approximately 4-5 ug/dl to children's bloodlead. Accounting for the variability inherentin childhood behavior, nutrition, and physiology, it isestimated that total lead exposure, given 15 ppb in drinkingwater, would result in blood lead levels below 10 ug/dl in

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roughly 99 percent of young children who are not exposed toexcessive lead paint hazards or heavily contaminated soils.Therefore, a 15 ppb cleanup level would provide substantialhealth protection for the majority of young children. Most ofthe remaining lead problem will continue to be contaminatedsoils and old lead-painted housing.

In an April 10, 1989, Federal Register notice (54 LB14316) , EPA announced the availability of a guidance document andtesting protocol entitled, "Lead in School's Drinking Water,'1 toassist schools in determining the source and degree of leadcontamination in school drinking water supplies and how to remedysuch contamination. That document, which is also attached,'recommends that schools take remedial steps whenever the leadlevel at any drinking water outlet exceeds 20 ppb.RECOMMENDATION

Based on a review of these and other studies, it isrecommended that a final cleanup level of 15 ppb for lead inground water usable for drinking water is protective. If waterused for drinking purposes subsequent to achieving the cleanupgoal in the aquifer may need further treatment to account forlead contributions related to the distribution of water throughpipes, the responsibility for this additional treatment or thereplacement of lead-bearing water pipes lies with the persons whoare using or distributing the water. A concentration of lead of15 ppb in drinking water should generally correlate with a bloodlead level below the concern level of 10 ug/dl. in tomesituations, lowercleanujp levels may be_ apgrpj>riate_based onsite-sgec_if ic factors, iuch as multiple pathways 'of exposurecausedjpy jjiaoTfrgartttir-gtwr " " —

If the remedial action will include treatment and supplyingwater directly to the public for drinking water consumption,compliance vith a 15 ppb action level should be met at 90 percentof the tape to ensure that tha remedy is protective. When thelead KPONR is promulgated, applicable or relevant and appropriaterequirements of that rule should be met.FUTURE

After promulgation of the lead NPDWR, guidance will beissued discussing those, provisions of tha rule that may beapplicable or relevant and appropriate for Suparfund actions.

For further information pleAse ontaet yjjth zimmerman at

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DISCLAIMER

The recommendations in this document are intended solely asguidance. They are not intended and cannot be relied upon tocreate any rights, substantive or procedural, enforceable by anyparty in litigation with the United States. EFA reserves theright to act at variance with these recommendations and tochange them at any time without public notice.

Attachments*

cc: Directors, Waste Management Division, Regions I, v, VII, vniDirectors, Emergency and Remedial Response Division, Regiontv' rtors, Hazardous waste Management Division, Regions III,Vi, IX

directors, Hazardous Waste Division, Region X

SR306027

AR305969of the simulation. In addition to ground water elevations, transport of only one contaminant...

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