DYKEMA GOSSETT LETTER RE: RESA RESPONSE TO DEC 21 …

DykEMA Dykema Gossett PLLC 10 South Wacker Drive Suite 2300 Chicago, Illinois 60606

WWW.DYKEMA.COM

Tel: (312)876-1700 Fax:(312)627-2302 Jerome I. Maynard Direct Dial: (312) 627-2185 Email: [email protected]

January 18,2007

Ronald W. Murawski, Remedial Project Manager Diana Embil, Attorney U.S. EPA - Region 5 77 West Jackson Boulevard Mail Code: SE-6J Chicago, IL 60604

EPA Region 5 Records Ctr.

IlllllllllilllliPII ' lllllll 366117

Re: Tremont City Landfill BFOU, Response to Agency Comments to AAD, Confidential

Dear Ron and Diana:

Enclosed please find RESA's response to the comments submitted by the U.S. EPA ("the Agency"), including combined comments received from OEPA and the Agency's contractors, in a transmittal dated December 21, 2006. RESA anticipates that after meeting to discuss the response to comments and submission of any additional materials requested by the Agency, a revised and approvable AAD can be submitted soon thereafter. Once the AAD is approved, the initial draft Feasibility Study Report can be submitted for Agency review.

RESA looks forward to meeting with the Agency and OEPA in Columbus, OH on January 31, 2007 to review and discuss RESA's responses to the Agency's comments. RESA believes that the meeting will provide a good opportunity to reach consensus on any outstanding issues and to resolve any remaining confiision regarding the responses, thus expediting submittal of an approvable AAD. For RESA, Mr. Hagen, Mr. Hester, Mr. Renner, Mr. Siegel, Mr. Campbell and I will attend. We also hope to have Dr. Wayne Pettyjohn attend so that any questions or concems regarding the aquifer tests and conclusions from those tests can be addressed and resolved.

Regarding schedule and place for the January 31, 2007 meeting, we would be happy to meet at OEPA offices in Columbus if they are able and willing to host the meeting. If that is a problem, we can arrange a conference room meeting place in downtown Columbus through one of our members. We would suggest a 9:00 or 9:30 AM EST starting time for the meeting given the number and complexity of the issues for discussion to assure that there is adequate time to

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Ronald W. Murawski, Remedial Project Manager January 18, 2007 Page 2

address all of them. Please let us know the Agency's preference in those regards. Please do not hesitate to contact me or Dave Hagen with any questions regarding this matter.

Best regards,

DYKEMA GOSSETT PLLC

f'^-^ J. i^.^^..^ Jerome I. Maynard

cc: J. Keiser, CH2MH S. McChesney, OEPA M. Allen, OEPA

CHICAG0\2279655.1 IDUIM

CALIFORNIA I ILLINOIS | MICHIGAN | WASHINGTON D.C.

RESPONSES TO U.S. EPA Comments on the Haley & Aldrich, Inc. November 2006 Draft Alternatives Array Document and November 22,2006 (E-Mailed) Response to U.S. EPA

Comments; Tremont City Landfill Site Barrel Fill Operable Unit; Clark County, Ohio

GENERAL COMMENTS

1. The Altematives Array Document (AAD) was not developed in conformance with the requirements of the October 2002 Administrative Order by Consent (AOC). Task 5 of the Statement of Work (SOW) attached to the AOC identifies the requirements for the AAD, including factors to consider in developing specific remedial and removal action objectives (RAOs), identification of applicable or relevant and appropriate requirements (ARARs), and "to be considered" (TBC) criteria and guidance. RAOs and ARARs were not always developed properly or included.

For example, the SOW requires certain types of altematives to be developed, including in-place containment and treatment. Given that 24 of the 50 drums tested during the barrel fill Rl would be considered hazardous waste under RCRA today, relevant and appropriate ARARs for in-place containment without treatment to remove hazardous characteristics would appear to be Ohio's Hazardous Waste Landfill Closure and Post-Closure Care rules, and/or the federal RCRA Subtitle C rules for Hazardous Waste Landfills. If the hazardous wastes were removed and/or treated on-site (so as to render them non-hazardous) and replaced, the relevant and appropriate ARARs for containment would be Ohio's Closure rules for Sanitary Landfills and/or the federal Subtitle D rules for Solid Waste Landfills. On-site treatment of affected media and/or wastes to remove hazardous characteristics may or may not involve hazardous waste treatment and storage rules depending on whether placement triggers such rules. The list of Ohio ARARs previously provided by U.S. EPA appear to have not been considered, for the most part.

RESA Response The draft alternatives array document (the "AAD") was developed in general conformance with the AOC and associated SOW. Discussion of appropriate approaches to both RAOs and ARARs between the agencies and RESA is ongoing; RESA anticipates that all issues will be adequately resolved before submission of the draft final AAD. The list of Ohio's ARARs provided by U.S. EPA was used in preparing the draft AAD.

The completed and approved remedial investigation (the "Rl") demonstrates that certain of the wastes in the BFOU meet standards to be classified as RCRA regulated hazardous wastes. Any remedial action that includes contaiwnerit of those wastes without treatment will need to be consisterU with federal RCRA landfill closure regulations, and Ohio's hazardous waste regulations if more stringent than the analogous federal regulations.

2. The lack of information provided in support of the identification and screening of process options and technologies makes review difficult. It appears that in some places, the guidance documents referenced in the AOC were not followed. For example, Task 5 of the SOW states that RAOs shall consider "acceptable chemical specific contaminant levels, or ranges of levels, for all exposure routes." Acceptable chemical specific contaminant levels for all exposure routes were not provided in the AAD; however, this information is necessary for, among other things, the identification and screening of treatment technologies, which is a primary consideration in the development of altematives. Task 5 in the SOW suggests that the use of presumptive remedy guidance may provide an immediate focus to the identification and analysis of altematives, but presumptive remedy guidance does not appear to have been considered. In the absence of a presumptive approach, the identification and screening of process options and technologies (and the remainder of the

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development and screening of altematives) should be performed in accordance with the processes and criteria developed for this purpose in U.S. EPA's "Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA" (RI/FS guidance) and "Conducting Remedial Investigations/Feasibility Studies for CERCLA Municipal Landfill Sites" (Municipal Landfill Guidance), both of which are referenced in the SOW.

RESA Response: The draft AAD was developed consistent with the requirements of the AOC and the RI/FS Guidance. Given that the wastes at the BFOU are varied and the chemical analyses of these wastes included numerous VOCs, SVOCs, herbicides', pesticides, and metals, it is simply not realistically practical to develop appropriate chemical specific remediation goals for all COCs and exposure routes. Given the potential for these complex mixtures to exist in the waste and subsequently in shallow groundwater and soil vapor, it is far more prudent and practical to develop target risk levels for reasonably anticipated exposure routes in these media. The draft AAD established such risk levels. This approach is common and has been used at other CERCLA sites in Region 5 and elsewhere and is consistent with the intent and goals of the SOW.

Agency presumptive remedy guidance documents were reviewed and considered during development of the draft AAD. However, no agency presumptive remedy guidance documents were identified for industrial waste landfills that contain hazardous wastes such as the BFOU. The Agency's municipal landfill presumptive remedy guidance ("Municipal PRG") is not applicable, relevant or appropriate to the BFOU because there is no municipal waste in the BFOU although the Municipal PRG presumptive remedy of containment of the wastes was considered. The Municipal PRG and Municipal Landfill Site RI/FS Handbook guidance documents were both considered regarding investigative techniques to be used during the Rl. Many of those techniques were applied during the Rl. The Rl is completed and has been approved and further consideration of investigative techniques is not relevant to the AAD. Regarding remedial actions, the Municipal PRG assumes containment as the appropriate remedial action and containment is one of the remedial options included in the draft AAD to be carried forward for detailed analysis in the FS. Finally, it should be noted that guidance documents may or may not apply to site specific issues in the performance of a Rl and feasibility study (the "FS, " together "RI/FS") such as those being performed at the BFOU but the relevance of such guidance documents is limited to guidance, not to application as hard and fast rules. Guidance documents should be carefully considered and used as appropriate, but the specific rules of the National Contingency Plan, 40 CFR Parts 300 et seq. are ultimately controlling in the performance of the BFOU RI/FS.

3. The SOW requires that the AAD identify ARARs that will apply to the remedial action and describe how the ARARs will be met. In addition to the table of ARARs and TBCs included in the document, the AAD should describe how each proposed remedial altemative meets its respective ARARs, or justify ARAR waivers based on the NCP criteria for that purpose.

RESA Response: The AAD will be modified to clarify that ARARs will be met by each remedial alternative under consideration. A general description of how the ARAR will be met will also be provided. For example, the Clean Water Act will be identified as an ARAR and the AAD will specify that the ARAR will be met for on-site groundwater treatment systems by meeting the substantive NPDES discharge requirements.

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One of the RAOs considerations identified in Task 5 of the SOW is "stabilization or elimination of hazardous substances in dmms, barrels, tanks, or other bulk storage containers that may pose a threat of release." Based on information in the Rl Report, the barrel fill meets many of the "hot spot" criteria identified in U.S. EPA's "Presumptive Remedy for CERCLA Municipal Landfill Sites." The presence and location of the waste is known, a large portion of the waste is principal threat waste, the waste is discrete, it is in accessible locations, and the area of contaminated waste is large enough that its remediation will significantly reduce the threat posed by the BFOU but small enough that it is reasonable to consider removal and/or treatment (approximately 16,000 cubic yards of drummed and bulk liquid waste in the cells). Based on these operable unit (OU) characteristics, more than one remedial altemative that includes removal and/or treatment of the principal threat waste (including highly contaminated soils that may surround the drums and bulk wastes) should be evaluated in the AAD. More specifically, an altemative that removes the dmmmed waste, segregates and bulks that waste on-site based on hazardous waste and TSCA criteria, transports the bulked wastes off-site for appropriate treatment and disposal based on waste classification, and treats non-liquid bulk wastes (including highly contaminated soils) on-site to remove hazardous characteristics prior to on-site containment should be included.

RESA Response: As noted above, the "hot spot" references in Agency municipal landfill guidance documents are not applicable, relevant or appropriate for the BFOU. Investigative techniques for "hot spots "from those guidance documents were considered and used as appropriate during the Rl. The Rl has been completed and approved and no further consideration of "hot spot" investigative techniques is required. RESA disagrees that the BFOU meets many of the "hot spot" criteria in the Agency's guidance documents and does not intend to utilize "hot spot" guidance as part of the remedy evaluation. The BFOU fails to meet the fundamental definition of "hot spot" because it does not consist of an area of concentrated containerized wastes within a landfill filled with uncontainerized heterogenous wastes.

Removal of the drummed wastes followed by on-site treatment was considered in drafting the initial array of remedial alternatives to be considered for the BFOU. Because this altemative offers no advantages over the retained altemative of removal and off-site treatment/disposal in elimination of risks or order of magnitude costs savings, but does include additional risks to workers and community and is not reasonably implementable due to the nature of the wastes likely requiring on-site incineration, it was not included in the final array of remedial actions to be further considered in the draft AAD and ultimately in the FS. Removal of drummed wastes followed by off-site treatment was included in the draft AAD and will be carried forward for detailed analysis in the FS.

The AAD describes permeability tests of the till 10 ft bgs ranging from 3.71x10"' to 1.04 x 10"' cm/sec with an average of 2.04 x 10"' cm/sec. The AAD also describes calculated vertical hydraulic conductivities of the till between the 1075 htertill and the 1050 htertill ranging from 1.3 x 10"' to 2.4 X 10"̂ ' cm/sec with an average (geometric mean) of 1.3 x 10"'̂ . The authors acknowledge that the calculated vertical conductivities are "not represented in prevailing hydrogeologic literature for naturally occurring materials." This is correct. Prevailing literature generally identifies homogeneous clays as having permeabilities between 10"̂ and 10"', and these are tills, not homogeneous clays.

There is uncertainty regarding the permeability of the till. There is uncertainty regarding the vertical hydraulic conductivity of the till. Based on the Rl Report, there is uncertainty regarding the origin of VOCs detected in the sand seams beneath the till, and there is uncertainty regarding flow in these

PAGE 3 OF 25

units. The permeability and hydraulic conductivity values derived during the Rl are nonetheless relied upon in the AAD to assert that releases from the barrel fill cannot migrate vertically so as to affect groimdwater in sand seams beneath the barrel fill, and this in turn is used to screen technologies and limit the scope or remedial altematives. The Rl Report and AAD hypothesize that the VOCs in the sand seams are related to landfill gas from the adjacent landfill, a conjecture that, given BFOU conditions, seems highly unlikely. The subsurface conceptual BFOU model which the AAD relies on would appear to conflict with the conclusions of previous investigations, including the U.S. EPA Site Investigation Summary. Although non-treatment and non-excavation altematives with contingent remedies may be considered, the AAD should more emphasize altematives involving treatment and excavation of the principal threat.

RESA Response: The data from the permeability tests at the BFOU, including the extensive aquifer pump tests, speak for themselves. The design of the permeability tests was reviewed and approved by both U.S. EPA and OEPA before the tests were conducted. The permeability tests including the aquifer pumping tests were overseen by both U.S. EPA and OEPA. The data generated by those tests meets QA/QC standards as defined in the work plans. The Rl reported all of that data and drew appropriate conclusions from the data, and the Rl was approved as complete and acceptable by U.S. EPA after review and comment by OEPA. In addition, RESA retained a third party peer reviewer. Dr. Wayne Pettyjohn, to review and comment on the aquifer test work plan, data analysis and reporting. Dr. Pettyjohn concurred with the aquifer test approach, data analysis and reporting. Dr. Pettyjohn's imprimatur is included as Appendix Xto the Rl Report. Appropriately, the AAD summarizes the data as reported in the approved Rl.

Based on the extensive permeability testing done during the Rl, virtually all uncertainty regarding the permeability of the tills surrounding and underneath the BFOU has been eliminated. The agency provides no basis for their conclusion that it is "highly unlikely" landfill gas is a possible source of the very low level VOCs identified in sand seams given the known and documented landfill gas issues associated with the landfill and the currently uncontrolled landfill gas conditions identified by OEPA and the Clark County Health Department at the landfill. The "stair step " theory of contaminant transport contained in the Site Investigation Summary has been superseded by Rl data regarding actual permeability of the till beneath the BFOU. One of the alternatives retained in the draft AAD is removal and off site treatment of wastes in the BFOU.

The AAD identifies the Water Table groundwater zone, soil vapor, and waste as primary media of concem, and it identifies the surface water and sediment, the 1075 Intertill and deeper groundwater units, and indoor air as the secondary media of concem. However, it is unclear how the media were designated as primary or secondary media of concem. It makes sense to designate the primary media of concem as those media that are currently contaminated at a level that poses an unacceptable risk level and/or may act as a source of contamination to secondary media in the future. The secondary media of concem would be those media that are not currently contaminated at levels that pose an unacceptable risk but have the potential to be contaminated in the fiiture.

RESA Response: As stated above and as we had intended, it is appropriate to identify primary media of concern as those media that are currently contaminated at a level that poses an unacceptable risk level and/or may act as a source of contamination to secondary media in the future. Also as stated above, secondary media of concern are identified as those media that are not currently contaminated at levels that pose an unacceptable risk but

PAGE 4 OF 25

have the potential to be contaminated in thefiiture. The draft AAD will be modified to provide these definitions.

1. In-situ treatment of groundwater should be included as a component of one or more remedial altematives in the AAD.

RESA Response: The draft AAD will be modified to include an in-situ groundwater remedy such as a funnel and gate in-situ groundwater treatment altemative.

8. The AAD does not describe how the proposed remedial altematives will address soil vapor. While institutional controls are mentioned in Section 7, it is imclear fi-om the text how these controls would mitigate risks fi-om soil vapor.

RESA Response: The risk to soil vapor exposures is currently acceptable and is not reasonably anticipated because it would only occur if residents were to build houses on the BFOU. Since this is not a reasonably anticipated exposure, it was not, and should not be, considered as a basis for screening of remediation altematives. In addition, all of the remedial altematives screened into the FS included additional institutional controls that will include the prohibition of residential buildings on the BFOU beyond the prohibition already contained in Ohio regulations to building such residences on a permitted landfill. The draft AAD will be modified to clarify this issue.

9. The SOW specifies that a general schedule for the remedial actions and/or removal actions should be developed, including both the start and completion time for the remedial action. A remedial schedule was not included in the AAD. Please note that a statement explaining that a remedial altemative will take one or two years to complete does not constitute a schedule. Additionally, no schedule was included for long-term activities, such as groundwater monitoring.

RESA Response: The draft AAD will be modified to include a more detailed schedule, including for long term monitoring although such a schedule can only be approximate and conceptual for remedial actions at the conceptual stage.

10. Once the altematives have been redeveloped, the adequacy of existing data to support the detailed analysis of altematives needs to be assessed and data gaps and/or the need for treatability studies identified. By way of example only. Monitored Natural Attenuation (MNA) has been retained, yet the data to evaluate MNA during the detailed analysis has not been developed. See Section 4.3.3.3 of the RI/FS guidance.

RESA Response: Under U.S. EPA CERCLA regulations, guidance and policy, the Rl data must be adequate to support remedial action decisions. The Rl conducted at the BFOU is no exception, and the data from the Rl are adequate for remedial alternative evaluation in the FS. While it is true that treatability studies may be a part of the FS process, they are not part of the AAD process since the AAD is undertaken at the screening level. The need for treatability studies will be addressed as part of the FS. We also note that treatability studies as part of a FS are not required by guidance. The need for treatability studies is evaluated based on site and project specific issues. Treatability studies are not normally needed for remedy evaluation in the FS.

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11. General Comment 8

Section 1.4.1 indicates a potential future human health risk based on potable use of the groundwater in the 1075 Intertill, and Section 3.1.1 identifies this unit as a media of concem. However, the remainder of the document does not include any discussions or evaluations for addressing potential future risks firom exposure to groundwater contamination in the 1075 Intertill. The document should include this information.

Response: The AAD will be modified to address potential future risks associated with the 1075 Intertill.

Comment: The AAD has not been modified as indicated in the response. The potential unacceptable risk associated with potable use of groundwater from 1075 Intertill was deleted in the summary of the human health risk assessment (Section 1.4.1). This is a departure from the Rl report and is inconsistent with the findings of the human health risk assessment (HHRA). Rather than modifying the AAD to address fiiture risks associated with the 1075 Intertill, the revised AAD assigns the 1075 Intertill as a secondary media of concem and essentially dismisses it. Section 3.1 indicates that "monitoring and contingency planning are required to ensure that remedial efforts on primary media of concem are successful at preventing unacceptable risk from secondary media of concem." Additional information on how this will be accomplished should be included in the revised document.

RESA Response: The draft AAD will be modified to clarify potential risks associated with the 1075 Intertill and how those risks would be addressed by the remedial altematives. Also, the 1075 Intertill will be added as a primary media of concern.

12. General Comment 10

The ARARs tables in the AAD should include federal advisories, criteria, and guidance.

Response: The ARARs table will be modified to include federal advisories, criteria and guidance.

Comment: Review of Table 3 (Summary of Potential ARAR and TBC Guidance) indicates that certain federal and Ohio guidance documents were added to the ARARs list.

A review of the electronic copy indicates that Table 3 (also Tables 4, 5, and 6) have hidden rows. It is uncertain whether the author intended that these rows to be retained or deleted for the final document. The hidden rows include regulations such as the Clean Water Act and RCRA 40 CFR Parts 258 and 261. According to Task 5 of the SOW, the AAD shall identify all ARARs and other federal or State advisories, criteria, or guidance to be considered that will apply to the remedial action, and shall describe how the ARARs will be met. This version of the AAD remains deficient with regards to ARARs. The hidden/deleted requirements are summarized in Table 1.

TABLE 1

Requirements Deleted fi"om Table 3-Summary of Potential ARAR and TBC Guidance

Applicable, Chemical, TBC, or Action, or

Relevant and Location Potential Requirement Appropriate Specific Requirement Synopsis

Federal

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TABLE 1 Requirements Deleted from Table 3-Summary of Potential ARAR and TBC Guidance

Potential Requirement

40 CFR 141 and 42 u s e §§ 300 er 569-Safe Drinking Water Act

42 u s e § 300g-l and Health Advisories -Maximum Contaminant Level Goals

33USC§§1251e/5e9. Clean Water Act

Applicable, TBC, or

Relevant and Appropriate

Relevant and appropriate since the site is not a public water system

40 CFR Part 260 -General Hazardous Waste Systems Management

40 CFR Part 263 -Standards Applicable to Owners and Operators of Hazardous Waste TSD Facilities (RCRA)

Chemical, Action, or Location Specific

Chemical

TBC Chemical

Requirement Synopsis

This statute applies to public water systems and can be considered relevant for groundwater aquifers potentially used for drinking water sources. CERCLA Section 121(d) requires MCLGs to be attained where such goals are relevant and appropriate under the circumstances of the release.

This statute establishes maximum contaminant level goals (MCLGs) for public water systems, which are unenforceable goals for the quality of public water systems. MCLGs are conservatively set at levels for which there are no known or anticipated adverse health effects.

Applicable for off-site discharges of treated water to surface water. substantive requirements are applicable for on-site discharges

Chemical, Action

''

This act sets forth various provisions relating to the prevention of water pollution from proint sources and the maintenance of surface water quality. Non-point source pollution is not conti-olled except through the setting and maintenance of water quality.

Applicable

Relevant and appropriate

Action These regulations set forth procedures and criteria for modifying other provisions of RCRA.

Action These regulations establish minimum national standards for owners and operators of TSD facilities.

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TABLE 1 Requirements Deleted fi"om Table 3-Summary of Potential ARAR and TBC Guidance

Applicable, Chemical, TBC, or Action, or

Relevant and Location Potential Requirement Appropriate Specific Requirement Synopsis

40 CFR 264 - Standards for Owners and Operators of Hazardous Waste Treatment, Storage and Disposal Facilities.

40 CFR 257 -Classification of Solid Waste Disposal Facilities (RCRA)

40 CFR Part 270 -Hazardous Waste Permit Program

16USC§§ 153\ etseq., 50 CFR Part 200, and 50 CFR Part 402 -Endangered Species Act (1973)

16 u s e §§470, 36 CFR Parts 65, and 40 CFR 800 - National Historic and Historical Preservation Acts

Substantive requirements are applicable if hazardous wastes are treated, stored or disposed on-site.





Action These regulations delineate requirements for placement of a cap over hazardous waste, run-on/run-off prevention, property use restrictions, and operation and maintenance requirements.

Action These regulations, although the site is under CERCLA, establish standards for the classification and management of the disposal of solid wastes, if applicable, or residuals.

Action These regulations establish requirements for obtaining RCRA program permits.

Location These provisions require actions to conserve a critical habitat upon which an endangered species depends.

Location These provisions require actions to protect historic and cultural artifacts and properties.

Ohio Requirements

OAC 3734.02(A) -Variances, Solid Waste Facilities, Emergency Permits

OAC 3734.02(G) -Permitting Exemptions, Solid Waste Facilities

Substantive Action requirements are applicable if hazardous wastes are treated, stored or disposed on-site.

Relevant and Action appropriate

This statute allows the Director of OEPA to issue a variance from a solid waste requirement provided that it will not create a nuisance or a hazard to the public health, safety, or the environment.

This statute allows the Director of OEPA to exempt any person generating, collecting, storing, treating, disposing of, or transporting solid or hazardous

PAGE 8 OF 25

TABLE 1 Requirements Deleted from Table 3-Sununary of Potential ARAR and TBC Guidance


Applicable, TBC, or


Chemical, Action, or Location Specific Requirement Synopsis

wastes in such qualities or under such circumstances that are unlikely to adversely affect the public

OAC 6111.03- Powers of Relevant and the Director, Impacts to appropriate Wetlands

Action This statute gives the Director of OEPA powers to make orders and grant permits (wetlands) which may vary from statutory requirements. Certain prerequisites and conditions may be required.

Ohio Water Requirements

OAC 3754-10 -Voluntary Groundwater Classification and Response Requirements

OAC 3745-33 - Ohio hidividual NPDES Permits

OAC 3745-38 - Ohio NPDES General Permits


Applicable for off-site discharges of ti-eated water to surface water, substantive requirements are applicable for on-site discharges


Action, Chemical

Action

Action

These regulations set forth standards by which to classify State of Ohio groundwater and response action requirements based on the classification.

These regulations define thresholds and require permitting of specific discharges to surface waters of the state.

These regulations define thresholds and requirements to be met for a General permit for discharges to surface waters.

PAGE 9 OF 25

TABLE 1 Requirements Deleted from Table 3-Summary of Potential ARAR and TBC Guidance


Ohio Air Requirements

OAC 3745-31-PTIs for New Sources of Pollution

OAC 3745-35 - PTOs for Sources of Air Pollution

Applicable, TBC, or


Substantive requirements are applicable for on-site waste treatment operations

Substantive requirements are applicable for on-site waste treatment operations

Chemical, Action, or Location Specific

Action

Action

Requirement Synopsis

This regulation provides the mles on appropriate permitting for the installation of new/modified air emissions sources. Also lists categorical exemptions to permitting requirements.

This regulation provides the mles on appropriate permitting for the operation of air pollution sources at non-Title V facilities.

Ohio Waste Requirements

OAC 3745-27 - Sohd Waste Regulations

OAC 3745-28 - Solid Waste Disposal Fees

OAC 3745-37 - Licenses for Solid Waste Facilities

OAC 3745-76 -Municipal Solid Waste Landfill Emissions

Relevant and Action These regulations specify the appropriate requirements for constmction,

permitting, operation and closure of solid waste disposal facilities.

Relevant and Action This regulation specifies the appropriate requirements for solid waste

disposal facility fees.

Relevant and Action This regulation specifies the appropriate licensing requirements for solid

waste disposal facilities.

Relevant and Action This regulation specifies the appropriate requirements for municipal solid

waste (MSW) landfills and explosive gas emissions.

RESA Response: The draft AAD ARARs Table 3 will be modified consistent with this response to comments.

13. While the AAD is provided to define the broad scope of the potential remedial actions and to present a preliminary screening and evaluation of the altematives identified (i.e., representative options), it should be noted that fiirther details on scope and evaluations must be provided in the FS Report.

PAGE 10 OF 25

Specifically, additional details of the monitoring program (e.g., media, aquifer units, triggers, etc.) and when contingent remedial actions will be determined and implemented should be included in the FS Report.

RESA Response: Noted.

SPECIFIC COMMENTS

1. Specific Comment 2—Section 1.2, second set of bullets

The list of bulleted items is reported to present the conclusions of the Rl Report. The conclusions should be reviewed for consistency with the Rl Report as well as Section 1.4 of the AAD. The exposure scenario (e.g., current or future) of which a specific medium may potentially pose an unacceptable risk should be clearly and consistently defined.

Response: The AAD xvill be modified to incorporate the above comment.

Comment: While the AAD has been modified to incorporate the findings summarized in the Executive Summary of the Rl Report, the summary of the HHRA has eliminated the potable use of groundwater from the 1075 Intertill as having an unacceptable future risk (refer to General Comment 8 above). This risk needs to be added to the AAD.

RESA Response: Noted. The revised draft AAD xvill address this comment.

2. Section 1.2, Groundwater Quality, second tick

Revise the first sentence that starts with, "the very concentrations of volatile organic compounds..." It appears that the word "low" should be inserted between "very" and "concentrations."

RESA Response: The requested modification xvill he made.

3. Section 1.3, Areas and Volumes, second bullet.

The second sentence needs to be revised, as bulk sludges were not placed in all cells.

RESA Response: The referenced sentence xvill he revised to note tliat records document placement of hulk sludges in some of the cells.

4. Specific Comment 11—Section 1.4.1, second paragraph

In addition, give the criteria used to determine the "unacceptable risk" in the HHRA (U.S. EPA Comment 6).

Response: The criteria used to determine the unacceptable risk will be added to the revised AAD.

Comment: The intent of this comment was for this information to be provided earlier in the document (i.e., in Section 1.4) rather than first presenting it in Section 3.3.

RESA Response: Tlie revised draft AAD will address this comment.

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5. Specific Comment 17—Section 3.1, first paragraph

Based on the bullets in Section 3.1.1, the groundwater in the 1075 Intertill was also identified as a media of concem. According to Section 1.4.1, revise the reference from "waste containing hazardous substances within the BFOU" to "materials in the waste cells."

Response: The AAD text on media of concem will be revised to indicate the 1075 Intertill is a primary media of concem. In addition, we will make the above-noted text change in the second part of the comment

Comment: Refer to the comment on General Comment 8 above.

RESA Response: The revised draft AAD will address this comment.

6. Section 3.1.1, Media of Concem: This section identifies primary and secondary media of concem. Please clarify how these media were designated as primary or secondary media of concem (refer to General Comment 6).

Additionally, the statement claiming that "by addressing the primary media of concem, the secondary media of concem are also addressed" may not always be accurate in light of the proposed remedial altematives. For example, remedial altematives 2 and 3 call for monitoring, contingency planning and/or collection and treatment of the Water table aquifer at the eastern edge of the barrel fill. While these altematives may address potential contamination of the sediment and surface water, they would not prevent migration of contaminants in the water table aquifer to migrate downward into the lower groundwater zones.

RESA Response: The potential jbr migration of contaminants from the shallow groundwater to the lower groundwater is extremely remote given the hydrogeologic conditions at the site. Vertical migration is controlled by the presence of tens of feet of low permeability till interbedded with sands ("intertills"). Regardless of these conditions, we agree that monitoring and contingency planning Jbr all of the groundwater units beneath the BFOU is appropriate.

Given the above, we intend to modify the above statement by saying "by addressing the primary media of concem through appropriate remedial responses developed Jbr BFOU site-specific conditions including hydrogeology ".

1. Section 3.11, Contingency Planning: The sentence "Monitoring and contingency planning are required to ensure that remedial efforts on primary media of concem are successfiil at preventing unacceptable risk from secondary media of concem" is not related to the identification of media of concem and should be removed. Additionally, it is not clear what is to be monitored and why, or what is meant by "contingency plaiming." If a contingent remedy is being proposed, it needs to be developed and screened along with and as part of the other altematives, clearly identifying which altematives contain contingent components.

RESA Response: The revised draft AAD will clarify how primary and secondary media of concem were dejined. The Rl, including the risk assessment, identified no risk to the lower acfuijer. Nonetheless, the draft AAD will be modified to clarify that monitoring of potential impacts to the lower aquijer xvill be included and that the contingency plan will include

PAGE 12 OF 25

groundwater contaminant control and treatment if such monitoring identifies a risk to the lower groundwater units. For clarification, a contingent remedy{s) is not being proposed. A contingency plan will be included in the FS Report.

8. Specific Comment 19—Section 3.1.1

Section 3.2.1 states that maintenance workers and trespassers may be exposed to constituents in surface water and sediments. Therefore, in Section 3.1.1, sediments should be added as a medium of concem and included in any analysis or evaluation involving media of concem.

Response: Maintenance workers and trespassers only represent a future risk if contaminated groundwater from the waste cells migrates to the unnamed tributary. Accordingly, there is no current risk to either of these potential receptors as is implied by the above comment. The AAD text on media of concem will be modified to more clearly state that this is a future risk only and that surface water and sediment are therefore secondary media of concem. If contaminated groundwater is not allowed to migrate to the unnamed tributary, then there would be no future risk from this media to these receptors.

Comment: This is similar to General Comment 11 above. Rather than modifying the AAD to address media of concem, the revised AAD assigns the surface water and sediment as secondary media of concem, and essentially dismisses them. This is a departure from the Rl Report and is inconsistent with the findings of the HHRA.

RESA Response: Tlie Rl report clearly states that surface water and sediment represent a future risk only. As stated above, if contaminated groundwater from the waste cell area moves to the unnamed tributary, then an unacceptable risk has been predicted to occur far maintenance workers and trespassers. Therefore, by addressing either the waste and/or the shallow groundwater, there is no need to address surface water and sediment. If monitoring indicates potential impacts on the unnamed tributary in the future, the contingency plan would provide a mechanism for addressing the issue before significant impacts occurred. The revised draft AAD will address this comment.

9. Specific Comment 21—Section 3.2.1, second paragraph, second sentence

Insert the word "cells" after waste and include reference to the 1075 Intertill. The sentence should read,"... hazardous substances in waste cells, shallow Water Table and 1075 Intertill groundwater, and...'

Response: The AAD text will be modified to address this and other comments on this section of the AAD.

Comment: The term "cells" has not been applied. Also refer to General Comment 11 above.


10. Specific Comment 22—Section 3.3.1, paragraph after the bullets

Revise the sentence to read, "...greater than a Hazard Index of 1.0 and an Excess Lifetime Cancer Riskof l0"^.."

Response: The AAD text will be modified as indicated by this comment.

PAGE 13 OF 25

Comment: The acceptable Excess Lifetime Cancer Risk range is 10"̂ to 10"*; consequently, an Excess Lifetime Cancer Risk greater than 10"̂ would also result in an unacceptable risk.


11. Section 3.4, Remediation Goals: Remediation goals are presented as risk levels and not as contaminant-specific concentrations. Once remediation goals are developed for each COC, receptor, and pathway combination, they are incorporated into the RAOs. The last three bullets in this section are not remediation goals as discussed in the RI/FS guidance and should be removed.

RESA Response: The draft AAD was developed consistent with the requirements of the AOC and U.S. EPA Guidance for performance ofRI/FSs. Given that the wastes at the BFOU are varied and the chemical analyses of these wastes included numerous VOCs, SVOCs, herbicides, pesticides, and metals, it is simply not possible to develop appropriate chemical specific remediation goals for all COCs and exposure routes. Given the potential for these complex mixtures to exist in the waste and subsequently in shallow groundwater and soil vapor, it is far more prudent and practical to develop remediation goals based on target risk levels for reasonably anticipated exposure routes in these media. The draft AAD established such risk levels. This approach is common and has been used at other CERCLA sites in Region 5 and elsewhere and is consistent with the intent of the SOW.

12. Section 3.5, ARARs: This section and Table 3 need to be revised based on the general comments above.

RESA Response: Vie revised draft AAD xvill address this comment.

13. Section 3.6, RAOs: This section also needs to be revised based on the general comments above. The first sentence of this section states, "remedial action objectives are based on COCs, medium of concem, exposure pathways and receptors, and allowable risk levels." An acceptable concentration for each COC also needs to be included. Many of these RAO components are not provided in the AAD. The RAOs need to be revised to meet the requirements of the SOW and to be in accordance with the RI/FS guidance. The RI/FS guidance states that RAOs should specify the contaminants of concem, the exposure routes and pathways, and an acceptable contaminant level or range of levels for each exposure route. Table 4.1 of the guidance document provides examples of appropriate RAOs for various environmental media. These examples should provide a basis for the level of detail that should be included in the RAOs in the AAD.

Correcting this will address one of the seven factors listed in the SOW to be considered during RAO development. The remaining factors also need to be addressed. Factors listed in the SOW that were not reflected in the development of the RAOs include stabilization or elimination of hazardous substances in dmms, barrels, tanks, or other bulk storage containers that may pose a threat of release; treatment or elimination of hazardous substances, pollutants and contaminants in soils or sediments that may migrate; and elimination of threat of fire or explosion.

RESA Response: The draft AAD was developed consistent with the requirements of the AOC and U.S. EPA guidance for performance ofRI/FSs. Given that the wastes at the BFOU are varied and the chemical analyses of these wastes included numerous VOCs, SVOCs, herbicides, pesticides, and metals, it is simply not possible to develop appropriate chemical specific

PAGE 14 OF 25

remediation goals for all COCs and exposure routes. Given the potential for these complex matures to exist in the waste and subsequently in shallow groundwater and soil vapor, it is far more prudent and practical to develop target risk levels for reasonably anticipated exposure routes in these media. The draft AAD established such risk levels. This approach is common and has been used at other CERCLA sites in Region 5 and elsewhere and is consistent with the intent of the SOW. The specific factors referenced in the comment were considered in screening out remedial altematives from further consideration.

14. Specific Comment 24—Section 3.6

Add groundwater from the 1075 Intertill, surface water, and sediment as media of concem.

Response: The 1075 Intertill, will be added as primary media of concem. Surface water and sediment will remain as secondary media of concem. Please see the revised text for additional explanation.

Comment: The second bullet for RAOs for Water Table groundwater should indicate that the RAOs include both human health and ecological standards.

As presented in the revised text, there are no RAOs for the secondary media of concem. What monitoring results will trigger the implementation of an action beyond monitoring, and how will remedy effectiveness be monitored relative to the secondary media of concem?

RESA Response: It is not appropriate to set RAOs for Water Table groundwater based on ecological standards since there are no ecological receptors associated ivith this media of concem.

The details of monitoring, triggers, etc. will be provided in the contingency plan that will be developed as part of the FS.

15. Specific Comment 25—Section 4

Add groundwater from the 1075 Intertill, surface water, and sediment as media of concem.

Response: The 1075 Intertill will be added as primary media of concem. Surface water and sediment will be retained as secondary media of concem. Please see the revised text for additional explanation.

Comment: Refer to discussions for General Comment 8 and Specific Comments 19 and 24 above. In addition to how the monitoring plan will be developed, this section should include details of the monitoring (e.g., what media, contaminants, etc.) that will be conducted at the BFOU. Specifically, it should discuss how the primary and secondary media will be monitored to ensure that the remedy is effective. The section also gives the impression that no decisions relative to changes the monitoring program and overall remedy will be conducted until the Five-Year Review. U.S. EPA may require changes before that time.

RESA Response: We believe that this discussion is part of the more detailed FS and should not be included in the AA,D xvhich is a screening level document. Generally, monitoring programs for sites xvhere xvastes are left in place are standard in that all primary media of concem xvill be monitored and secondary media of concem xvill be monitored as required on a site specific basis to ensure that significant impacts to the secondary media ojconcem do not occur. If all xvastes are removed, no monitoring program will be required because all risks will have been removed. Monitoring programs for sites xvhere xvastes are left in place

PAGE 15 OF 25

customarily run for 30 years or until risks are eliminated and can be extended beyond the 30 year horizon if needed.

16. Specific Comment 26—Section 4 and Table 4

The general response action for in-situ treatment for groundwater was screened out in Table 4 based on "not proven for high sti-ength and heterogeneous waste cells." Although this may be tme for the barrel fill area (i.e.. Waste; see Section 4.7.2.1), in-situ groundwater treatment may be implemented near the downgradient edge of the plume or upgradient of the discharge area where containinant levels are not as high. A series of in-situ treatment technologies should be retained.

Response: In-situ technologies for groundwater will be retained and evaluated in the FS. We currently envision a funnel and gate technology as the highest probability for being retained into the FS.

Comment: Based on the areas downgradient of the waste cells where it could be implemented, in-situ groundwater treatment should remain in the AAD. The more detailed analysis (conducted in the FS) will determine whether this technology is feasible.

RESA Response: See above.

17. Section 4, GRAs: The first sentence of this paragraph states that general response actions (GRAs) are media-specific response actions. However, section 4 does not clearly identify which GRAs are applicable for each medium of concem. This section should be revised to either group GRAs by media or to include an additional section that specifies which GRAs are applicable to each media of concem.

RESA Response: The GRAs for individual media are provided on the tables. We xvill add a general discussion of the GRAs by media in the text.

18. Section 4.7.1, Source Removal: This overly general discussion of source removal should discuss both complete and partial source removal based on possible combination of source removal with in-situ treatment technologies. If partial removal is not feasible, this needs to be explained. Also, the discussion should identify which technologies would be employed; for example, for removal of dmmmed wastes vs. technologies that may be employed for removal of bulk wastes. Dredging is identified as a technology, yet it is not clear given BFOU conditions and the nature of the source wastes why dredging is being considered.

RESA Response: Removal of the drummed wastes followed by treatment was considered in drafting the initial array of remedial alternatives to be considered for the BFOU. Because the on-site treatment alternative offers no advantages over the off-site removal/treatment altemative in elimination of risks or order of magnitude costs savings, but does include additional risks to workers and community and is not reasonably implementable due to the nature of the wastes likely requiring on-site incineration, it was not included in the final array of remedial actions to be further considered in the draft AAD and ultimately in the FS. Removal of drummed wastes followed by off-site treatment was included in the draft AAD.

PAGE 16 OF 25

19. Section 4.7.2, Source Destraction/Treatment: The first paragraph of this section should discuss the concept of removal, segregation, and off-site disposal of liquid and TSCA source wastes, followed by in-situ or ex-situ treatment of remaining source materials exhibiting hazardous characteristics.

RESA Response: See response to specific comment 18.

20. Section 4.7.2, Source Destmction/Treatment: In-situ technologies would also include physical methods such as vapor extraction. This would also be tme for ex-situ treatment. Also, the word "physical" appears in the text, but it is not clear if it relates to solidification and stabilization of other technologies such as vapor extraction.

RESA Response: Noted. The revised draft AAD xvill address this comment.

21. Section 4.7.2.2, Ex-Situ: The added red-line text discussing the intent of the treatment (render source materials non-hazardous) would apply equally to in-situ methods. This statement would be better placed in the first paragraph of 4.7.2 (introductory paragraph) in that it applies to all of the technologies discussed, clearly indicating that the treatment technologies would only be applied to the source materials which would otherwise be considered hazardous waste. Also, it is not clear why off-site disposal would be considered for source materials treated to remove hazardous characteristics. On-site containment technologies should be identified in the appropriate section of the AAD for source wastes treated on-site to remove hazardous characteristics.

RESA Response: Noted. Please see response to specific comment 18. The revised draft AAD will address this comment.

22. Section 4.7.3, Ex-Situ Disposal: This appears to be a discussion of off-site disposal. It is not clear why it is referred to as "ex-situ" disposal, as ex-situ disposal could also theoretically occur on-site (constmction of a RCRA waste containment system). Also, the revised red-lined text implies that off-site disposal would require removal of the entire contents of the barrel fill including contaminated soil, bulk wastes, and contaminated water, regardless of characteristics. The only source materials that would require off-site disposal would be TSCA-regulated wastes and source materials that could not practicably be treated on-site to remove hazardous characteristics, and, possibly drummed non-hazardous liquid waste. Source materials that would be considered solid waste (as opposed to hazardous waste) would not need to be transported off-site for disposal. Off-site POTWs should also be discussed as an option for off-site treatment and disposal of contaminated water.

RESA Response: The discussion in Section 4 of the AAD is a general discussion of GRAs and is not specific to the BFOU (First paragraph "This section generically introduces the GRAs ") Also, in section 4.7.2.2 itis stated that "The intent of this technology [Source Destruction] xvould be to treat hazardous substances to render tliem non-hazardous xvaste (iffoasible and desired) for eitlier on site or off site disposal." [emplmsis added]. We xvill add text in 4.7.3 to make it clearer that this generic GRA can include on-site disposal. Given that this is a generic discussion, we believe specific reference to TSCA is not appropriate and is better handled in the section on ARARs and in the FS. Off-site POTWs for groundxvater discharge were discussed in Section 4.5 and xvill be added in Section 4.7.3.

PAGE 17 OF 25

23. Section 5.1, Bullet Items: The information included in this section should correspond more directly with Table 4. It is unclear how these broad statements influenced actual screening of each remedial technology and process option within each table for each media. It would be clearer if the bulleted items were grouped by media. There should be media and BFOU-specific information included in this section that corresponds to each process option or groups of process options that were screened out based on implementability. Please also see the related general comments.

RESA Response: The AAD will be revised to address this comment.

24. Comment 36—Section 6.1, first bullet (U.S. EPA comment 29)

The second sentence refers to the ability to recover hazardous substances. Is this equivalent to the ability to capture contaminated groundwater? If so, revise the sentence accordingly. If not, explain what the phrase "recover hazardous substances" includes.

Response: Yes, the two are equivalent and the AAD text will be modified as indicated by this comment.

Comment: The AAD text was not revised as indicated in the comment.


25. Sections 6.1, 6.2 and 6.3, Screening: Information should be included in this section that explains why certain technologies were screened out based on effectiveness, implementability, and cost.

RESA Response: The revised draft AAD xvill address this comment, and we intend to discuss this xvith you at our meeting planned for January 31, 2007.

26. Section 7, Remedial Altematives: The SOW specifies that the AAD shall define the broad scope and specific short-term and long-term objectives of the remedial action, and address the protectiveness of the remedial actions. The Rl Report indicates that the dmms and waste containers in the barrel fill will degrade and release hazardous substances over time. In light if this information, please provide additional information for each remedial altemative included in this section regarding its ability to meet long-term objectives and long-term protectiveness. Include a discussion of the long-term effectiveness of clayey till as a barrier to contaminant migration in the presence of high concentrations of chlorinated and other solvents. Discuss any changes in the permeability of the tiU that occur due to the presence of these solvents, and justify reliance on the till for purposes of long-term containment of such solvents in light of the wealth of existing information indicating otherwise.

RESA Response: The revised draft AAD xvill address this comment. Tlie long-term permeability of the till xvas addressed during the Rl, and specifically as part of the response to comments for the Rl report. The agency is directed to our response to comments #44 and #61 on the August 26, 2005 draft Rl report.

27. Section 7.2, Altemative 2

The description of this altemative needs to be expanded to include details of what the groundwater monitoring program will include (e.g., what hydrogeologic units will be monitored, the analytes, frequency, etc.) and how the data will be used to determine an "unacceptable risk to human health and

PAGE 18 OF 25

environment" and long-term effectiveness and reliability of the remedy. In addition, the description of the altemative indicates the potential to implement "contingent remedial actions if necessary." What are these contingent actions? Because the entire focus of the AAD is on the water table groundwater, what happens if the 1075 Intertill or deeper hydrogeologic units become impacted and a potential threat to downgradient receptors? How does this "altemative mitigate all threats to public health and the environment?"

The second paragraph indicates that "monitoring and contingency planning would start after remedy constmction." These activities should be included in the design of the remedy rather than once the remedy is constmcted.

RESA Response: The AAD is a screening lexxl document and does not include details as described above. Consistent with our discussions with the agency, these details are part of a contingency plan that will be included in the FS.

28. Sections 7.2 and 7.3, Remedial Altematives 2 and 3: These altematives include regrading the existing cap to promote drainage and minimize infiltration. However, Sections 4.6.1 and 4.6.2 state that 10 to 17 feet of uncontaminated, low permeability soil is present on the barrel fill, should be considered a contact barrier, and is appropriate as a cap. Based on this conflicting information, it is unclear whether the existing soil cover at the barrel fill is currently sufficient to act as a contact barrier and cap for containment at the BFOU. Please clarify.

RESA Response: The information does not conflict. Testing of the existing cover indicates that the cover material is suitable as a low-permeability cap. Given its thickness it also serves as a contact barrier. The drainage should be improved by regrading. Regardless of the permeability of the existing cover, promoting surface drainage will reduce the currently already very low infiltration rate.

29. Sections 7.2. and 7.3, Remedial Altematives 2 and 3: These altematives include regrading the existing cap to promote drainage and minimize infiltration. Please explain how the proposed cap improvements will meet ARARs, particularly related to cap requirements for solid and hazardous waste landfills.

RESA Response: As discussed in other responses, the ARARs will be re-evaluated in the revised AAD. As stated above, RCRA Subtitle C Regulations are relevant and appropriate. Accordingly, the AAD will be revised to reflect these requirements for the remedial options.

30. Sections 7.2, 7.3, and 7.4, Remedial Altematives 2, 3, and 4: It appears that groundwater monitoring is included in these altematives; however, it is unclear whether groundwater monitoring will be conducted in the Water Table groundwater zone or in all groundwater zones. It appears that groundwater monitoring of the deeper groundwater zones would be appropriate, as most of the remedial altematives will not prevent the movement of contaminants from the waste to the underlying groundwater zones. Please provide clarification as to which groundwater zones will be monitored for each remedial altemative.

RESA Response: As xve have discussed xvith the agency, site monitoring will include all groundwater units. We note tlie findings from the significant hydrogeologic testing conducted during the Rl and as presented in tlie approved Rl report are in direct conflict with the staternent

PAGE 19 OF 25

that "most of the remedial altematives will not prevent the movement of contaminants from the waste to the underlying groundwater zones." A more detailed approach to groundwater monitoring will be provided in the FS.

31. Sections 7.2, 7.3, and 7.4, Remedial Altematives 2, 3, and 4: The Rl Report includes some degree of uncertainty related to contaminant fate and transport in groundwater, groundwater flow direction, and surface water/groundwater interactions. In light of these uncertainties, additional information should be included in the AAD regarding the adequacy of the current groundwater monitoring network, as well as any plans for installation of additional wells. Also, information should be included regarding a sampling schedule in the FS Report.

RESA Response: Uncertainty exists xvith any scientific study and the Rl was no exception. The uncertainty section of the approved Rl report was written simply to articulate the uncertainty and does not invalidate the results, findings or conclusions. As we have repeatedly stated, the contingency plan including the groundwater monitoring approach is not appropriate in the screening level AAD and xvill be included in the FS.

32. Sections 7.2 and 7.3, Remedial Altematives 2 and 3: It appears that contingency planning included in these altematives should be considered contingent remedies. More information should be included regarding the proposed contingent remedies. This information should include examples of contingent remedies, when a contingent remedy would be triggered, who would be responsible for oversight and implementation of the contingent remedy, and financial assurance for funding the contingent remedy. Long-range level-of-effort requirements should also be considered based on the complexities of the proposed contingent remedy, as well as a discussion of what ARARS may be applicable to each contingent remedy, and how the contingent remedy will meet RAOs.

RESA Response: Contingent remedies are not part of an AAD or an FS because they are contingent upon events that have not occurred. For example and taken to its extreme, this comment could apply to all successive surjace waters connected to the unnamed tributary. Any future event xvill be addressed through the CERCLA process including contingency planning, five-year remedy reviews, etc. and should only be applied when the event occurs. However and as noted elsewhere, a general contingency plan will be described in the FS and if the selected remedial altemative includes contingency actions, a more detailed contingency plan can be developed during the remedial design stage.

33. Section 7.3, Altemative 3: Containment/treatment/discharge of the Water Table groundwater downgradient of the barrel fill is included in this altemative. While this may be effective in capturing contaminated groundwater before it discharges to the unnamed tributary, an upgradient containment system that would prevent Water Table groundwater from flowing through the waste cells in the barrel fill should also be incorporated into this remedial altemative. Upgradient groundwater containment, in conjunction with an impermeable cap, would reduce the amount of contaminated groundwater flowing off-site, downgradient of the barrel fill.

RESA Response: Tlie amount of groundxvater flowing through the BFOU in the Water Table groundwater has been calculated to be less tlian 1 gpm. While it is true that an upgradient groiindioater diversion system luould reduce this flow, from a practical standpoint this

reduction would likely be insignificant. Regardless, an upgradient shallow groundwater diversion structure xvill be considered for inclusion in tlie remedial altematives.

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34. Section 7.3 Altemative 3.

Will this altemative also include monitoring and contingency planning for the 1075 Intertill and deeper hydrogeologic units?

The second paragraph indicates that "monitoring and contingency planning would start after remedy constmction." These activities should be included in the design of the remedy rather than once the remedy is constmcted.

RESA Response: All groundwater units beneath at the BFOU xvill be monitored. The approach to this remedy component will be provided in the FS.

35. Section 7.4, Remedial Altemative 4: This altemative calls for the removal and off-site treatment and disposal of "source waste inside the cells." Based on the information in the section, it is unclear whether all waste in the cells will be removed or only the waste that presents a risk for contaminant migration to the surrounding media of concem. Please clarify. If certain wastes will remain in place, then media-specific ARARs should be provided along with an explanation of how these ARARs will be used to make decisions regarding waste removal.

RESA Response: Altemative 4 included the removal of all waste.

36. Section 7.4, Remedial Altemative 4: This altemative calls for the removal and off-site tieatment and disposal of contaminated soils (in addition to the waste). However, it is unclear as to what criteria will be used to evaluate whether soils will be removed or left in place. Please provide media-specific ARARs for soil and how these ARARs will be used to make decisions regarding soil removal.

RESA Response: Soils that present a risk to human health or the environment and/or that are characteristically hazardous xvould be removed and treated off-site under Altemative 4. As indicated in earlier responses, it is not practical to designate chemical specific contaminant levels given the unpredictable chemical mixtures that may be present at this site. Soil confirmation sampling xvill be used to determine if risk-based soil remedial goals are met. The details of confirmation sampling will be provided in subsequent documents (FS, RD, etc.).

37. Section 7.4, Remedial Altemative 4: Additional information should be added to this section specifying that Altemative 4 is consistent with the presumptive remedy guidance for landfills related to addressing hot spots. Refer to General Comment 2.

RESA Response: The Municipal PRG referenced in this comment by its terms is applicable only to municipal landfills. Tlie BFOU is not a municipal landfill and the referenced Municipal PRG reference to "hot spots" is not applicable, relevant or appropriate other then in assisting in defining appropriate investigative techniques as noted above. The Municipal PRG xvas considered in developing remedial alternatives..

38. References: The following references, as well as any additional applicable references listed in the SOW, should be added as references and added to Table 3.

PAGE 21 OF 25

USEPA, 1991a: A Guide to Principal Threat and Low Level Threat Wastes. 9380.3-06FS, USEPA, Washington, DC.

USEPA, 1993: Presumptive Remedy for CERCLA Municipal Landfill Sites. EPA/540/F-93/035, Washington, DC.


SPECIFIC COMMENTS ON TABLES

39. Table 3: OAC 3745-54 and 57, and the corresponding federal counterparts should be added to the ARARs list because they are relevant and appropriate for the barrel fill.

RESA Response: The revised draft AAD will address this comment. State regulations are only ARARs if they are more stringent then federal equivalent regulation. We note that only appropriate sections of specific ARARs xvill apply for specific remedy altematives.

40. Table 3, Applicable, TBC, or Relevant and Appropriate column: It is not clear what the repeated phrase "default to federal mles if state regs not enforced" means. Delete this statement throughout the table. State ARARs would only apply or be relevant and appropriate where they are more stringent than federal ARARs. Discussion of whether state regulations are "enforced" is inappropriate, and this issue would only be assessed by U.S. EPA in the context of considering a waiver of state ARARs based on the NCP's waiver criteria. If any technology or process option being considered would require a waiver in order to be implementable, the need for the waiver should be identified in Table 4.

RESA Response: We intend to change the sentence to read "defoult to federal rules if state regulations are only as stringent".

41. Table 3: The table should include chemical-specific ARARs or TBCs for waste and contaminated soils for directing remedial activities for any altematives that include removal of source materials, in-situ or ex-situ treatment of source materials, and/or off-site treatment and disposal of source materials.


42. Table 3. Additional information should specify the remedial altemative(s) and the specific components of the altemative(s) associated with each ARAR or TBC.

RESA Response: The revised draft AAD xvill address this comment.

43. The header for the last column needs to be fixed.

RESA Response: The revised draft /{AD xvill address this comment.

PAGE 22 OF 25

44. Comment 44—Table 4, Groundwater (Water Table), In-situ Groundwater Treatment

In-situ groundwater treatment technologies could be implemented downgradient of the barrel fill where high strength and heterogeneous waste cells would not apply. Therefore, these options should be retained for fiirther evaluation (See Section 4 and Table 4 comment.)

Response: See the response to Comment 26.

Comment: Refer to discussion on Specific Comment 26 above.

RESA Response: The rexnsed draft AAD will address this comment.

45. Tables 4 and 5, Groundwater (Water Table)

Groundwater extraction wells/sumps should also be included as a remedial technology for the containment general response action.

RESA Response: The revised draft /\AD will address this comment. Groundwater extraction wells/sumps will be included as a potential remedial technology as part of containment.

46. Table 5: It is not clear why all of the process options listed for "source removal with ex-situ source destmction/treatment, replacement at site" were screened out. In all cases but one, the process option was screened out based on effectiveness even though it was determined to be effective and reliable.

RESA Response: Details xvill be added regarding the bases for screening out altematives.

47. Table 5: It is not clear why many of the process options listed for Containment of Wastes were screened out or why sheet piling is not being considered. For example, the rationale for screening low permeability caps is not persuasive. ARARs will likely play a role in retaining this technology. Also, given the difficulties, yet to be resolved, in the calculations used to estimate vertical hydraulic conductivity in the till and the presence of contaminants in sand seams beneath the barrel fill, also yet to be resolved, there would not appear to be a sound basis for screening out an engineered slurry wall based on it being more permeable than the surrounding till.

RESA Response: Sheet piling was not considered because the tills have a density that precludes sheet pile installation. Please see our earlier response concerning the hydraulic conductivity of the tills. Tlie use of a slurry xvall xvould only be appropriate in geologic materials that have hydraulic conductivities greater than approximately 10-̂ cm/sec, the typical permeability of a slurry xvall.

48. Table 5, Institutional Implementability: Environmental covenants entered into pursuant to ORC 5301.08 - 5301.92 also require the participation of either Ohio EPA or U.S. EPA.

RESA Response: No response required to this comment.

49. Table 5: It is not clear why POTWs and TSCA/RCRA facilities have been screened out for ex-situ groundwater treatment. For example, dewatering water may be of a volume and quality that would allow hauling to a POTW as is done with the landfill leachate from the adjacent landfill. Also, all of the other technologies mentioned in this category under the Institutional Implementability column are

PAGE 23 OF 25

classified as "Easily Implementable." It would be more accurate to state that substantive permitting requirements would need to be met. The same would be tme for any other technology being considered for any medium or altemative that would result in an on-site discharge that would otherwise require a permit.


50. Table 5: It is not clear why sheet piling is screened out due to the presence of low permeability till. The argument that thin wall Shelby tubes collapsed during sampling is not persuasive. The till (and a good portion of the cover above it) are saturated, and thin "walls" between cells were observed to slump during test pit excavations. The presence of low permeability till is generally a prerequisite for considering the use of sheet piling, as it provides a low permeability substrate to key the sheet piling into. Given that a slurry wall is retained, these two technologies, representative of vertical barriers, should be screened against each other based on effectiveness based on BFOU and contaminant-specific conditions.

RESA Response: Please see the response to comment 47. The permeability of the till is not a factor

precluding sheet pile use.

51. Table 5: It is not clear why vapor extraction, both in-situ and ex-situ, is not being considered as a physical treatment for source wastes. This technology has been successfully implemented at similar sites to remove hazardous characteristics and allow on-site disposal of treatment residuals.

RESA Response: Vapor extraction is not ejfective at treating drummed wastes. The technology is generally applied to contaminated soils. In addition, because the waste is beneath the xvater table (saturated), the site geology consists of low permeability till, and many of the constituents of concem are not treatable with such technologies, vapor extraction was screened out.

52. Table 5, Waste, column titled Technology Screened out based on: Five of the six technologies are apparently screened out based on the need to do pilot studies. This is inappropriate. If pilot studies are needed, this is the time to do them (see General Comment 10 above). The sixth technology (thermal) is screened out based on implementability with a reference to permitting. This makes no sense. If the discharge from thermal treatment were on-site, no permit is required, just compliance with substantive requirements. Also, thermal treatment should consider low-temperature thermal desorption, a proven technology used successfully at similar sites, and catalytic oxidation as a tieatment for the discharge from vapor exti-action, a physical tieatment process.

RESA Response: The revised draft AAD xvill address this comment.

53. Table 5, column titled Technology screened out based on: The need for a permit is not sufficient reason to screen a technology, especially when the need for the permit is not clear. For example, under off-site discharge of groundwater, off-site discharge is screened out based on "Implementability - Permitting." On-site discharge is to a "local tributary" and off-site discharge apparently involves a "pipeline to unnamed tributary." Are the receiving streams different? If off-site discharge is to be screened, it would be screened as it costs more and is not necessary as long as an on-site discharge is capable of complying with substantive permitting requirements. These substantive requirements

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would apply equally to the off-site discharge, only they would be memorialized in an actual permit (as opposed to, for example, a ROD and/or an RD/RA order for the on-site discharge).


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DYKEMA GOSSETT LETTER RE: RESA RESPONSE TO DEC 21 …