Skip directly to search Skip directly to A to Z list Skip directly to site content

PUBLIC HEALTH ASSESSMENT for Bloomington PCB Sites

Bloomington, Monroe County, Indiana
Spencer, Owen County, Indiana


III. Responses to Public Comments on the Public Health Assessment for Bloomington PCB Sites, Volume I

Volume I of the public health assessment (PHA) represents a major data gathering and analysis activity that was the first comprehensive review of the Bloomington Consent Decree PCB (Polychlorinated Biphenyls) Sites. Under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR), Indiana State Department of Health (ISDH) representatives reviewed available data and information, conducted site visits, met with relevant private and public officials and completed a report titled Final Report, Preliminary Data Evaluation and Pathways Analyses Report for Consent Decree PCB Sites. The report was written in accordance with ATSDR - Public Health Assessment Guidance Manual (PHAGM), 1992. The report was released first for public comment (brown cover) in January 1994 and was then finalized (blue cover) in April 1994. ATSDR used the report to identify key issues for further evaluation. ATSDR considers the report to be Volume I of the PHA for the Bloomington sites.

When ATSDR released the public comment version (brown cover) of Volume II, Public Health Consideration of Remedial Technologies for the Bloomington PCB Sites, in September 1994, a number of individuals and organizations asked ATSDR to consider additional comments on Volume I. The agency agreed and since that time has been preparing responses to the many comments and issues received.

This section contains all written comments ATSDR received on Volume I from September 1994 through January 1995. The agency did not believe it would be appropriate or fair to the commenters to attempt to "summarize" their comments, which could result in a loss of perspective; therefore, the comments appear as received. This section is divided into three subsections: III.A., which emphasizes six overarching critical themes ATSDR identified after reviewing individual and general comments; III.B., which addresses general comments, i.e., those comments received by ATSDR that tend to cut across all sites or were summary in nature; and III.C., which contains responses to "specific" comments, i.e., those identified by a specific page number.

III.A. A summary of Themes That Run Through the Questions and Comments on the Public Health Assessment for Bloomington PCB Sites, Volume I, and Summary Responses That Respond Generally to Those Themes

  • AVAILABLE ENVIRONMENTAL DATA ARE OF POOR QUALITY AND NOT SUFFICIENTLY COMPLETE TO CHARACTERIZE THE SITES OR TO ASSESS PUBLIC HEALTH.

Many of the comments ATSDR received concerned the general completeness and quality of data on which the ISDH and ATSDR based their public health conclusions. (See comments #1-#4, #8, #10, and #12.) Data reviewed for the PHA come from a variety of sources, including the site owners or their contractors, government agencies (state and federal environmental agencies and county and city agencies), and concerned private citizens. Regardless of the source, health assessors evaluated the completeness and quality of all data. Health assessors were encouraged to mention all data evaluated during the process and to present clear explanations of any deficiencies, concerns, and limitations that might be associated with the data. They were also instructed to indicate clearly where and how they used the data to arrive at decisions. This has been done throughout this PHA process.

We always base decisions on whether to use data or not use data on our knowledge of the question or questions being asked or the issues being addressed. Several commenters expressed concerns about what they perceive to be deficiencies in quality and completeness of the environmental data. The commenters believe the perceived deficiencies precluded our ability to characterize the sites accurately in terms of 1) identifying all contaminants, not just PCBs, and the levels of contaminants present at sites and 2) estimating potential for off-site migration of site-related contaminants.

However, data other than site characterization data are also important to evaluating public health. Some of the other data ATSDR considers during the assessment of public health impact include toxicologic and epidemiologic data for substances of concern and information about the potential nature of human activities that bring individuals into contact with site-related contaminants. Data on activities that bring people into contact with the contaminants are often the most critical data available for evaluating public health impact. If human contact with contaminants is judged to be frequent and long term or appears likely to result in significant exposures, the quality and nature of the site characterization data become very important. If, however, activity patterns indicate that significant human exposures are not likely to occur, the quality of the site characterization data may not be as important for the judgement of public health impact.

ATSDR staff members have looked at the potential for human exposures to site-related contaminants during a number of visits to the various site locations. Consequently, ATSDR staff members believe that, despite the lack of environmental data or the poor quality of the environmental data available for most of the sites, they can still be confident in their public health judgements, based largely on information pertaining to the likelihood of exposure.

  • TOO MUCH EMPHASIS WAS PLACED ON PAST EXPOSURE PATHWAYS AND...PAST DATA SHOULD NOT HAVE BEEN USED TO ASSESS CURRENT EXPOSURES

Several comments were received that questioned why the PHA focused on past exposures rather than current exposures (e.g., #21, #23) and why "analytical results that were not representative of current conditions" were being used to determine current hazards (#73).

ATSDR and ISDH did not use past data to assess current exposures and hazards. ATSDR's PHAs cover the potential for past, present, and future exposures. In general, for many of the subject sites, historical environmental data were the only data available to the assessors. They used these data only to make initial judgements about the potential for exposure in the past. Estimates concerning present exposures and, to a limited extent, future exposures, were made on the basis of some limited current data, considerations of the interim remedial steps that had been taken, and consideration of human activity patterns that would result in contact and exposure to site-related contaminants. Therefore, developers of ISDH's preliminary report and ATSDR's additional analyses did not rely on historical (pre-interim) remediation data to assess current and future exposures.

It may be possible to use past environmental data to assess present and future exposures in certain situations. Such a situation could occur if there had been 1) no changes in the conditions at the sites that either would limit direct human contact with site contaminants or would have prevented or diminished migration of the contaminants from the sites or 2) no new environmental monitoring or sampling data. These situations do not apply to the Bloomington Consent Decree PCB Sites. Interim remedial steps have been taken to lessen the potential for exposure, and at some locations data are being collected routinely to monitor contaminant releases.

  • ANALYSIS PROCEDURES -- DIFFERENCES BETWEEN "COMPLETED" and "POTENTIAL" PATHWAYS IN PAST, PRESENT, and FUTURE TIME FRAMES.

A pathway is defined on page 6-1 of the ATSDR PHAGM as consisting of five elements: 1) source of contamination, 2) environmental media and transport mechanisms, 3) point of exposure, 4) route of exposure, and 5) receptor population. When data and information indicate that all five of the elements were, are, or will be present, then the pathway is characterized as "complete" for the appropriate time frame (past, present, or future).

The ATSDR PHAGM also provides guidance for the approaches to be used if one of the elements is or might be missing. Page 6-33 of the manual states that "a suspected pathway can be eliminated if at least one element, which would link the five elements, is absent and will never be present." Health assessors have interpreted this sentence to mean that a pathway cannot be eliminated unless one of the five elements has never been present or will never be present. Where there is any doubt about the presence or absence of an element, the health assessor assigns the pathway a designation of potential. Thus, the designation of potential is commonly used when information is considered too incomplete to reach a definitive conclusion regarding the characterization of the pathway.

By characterizing a pathway as completed, the health assessor does not automatically conclude that a public health hazard exists. The assessor uses professional judgement based on an evaluation of measured or estimated levels of exposure and an assessment of the related toxicologic and epidemiologic information for the contaminants of concern to determine whether a public health hazard exists. It is not unusual to have a completed exposure pathway that is not a public health hazard because the concentration of contaminants is so low or the public exposure is so limited that no public health hazard exists.

  • THE PHA FAILS TO RECOGNIZE THE EFFECTIVENESS OF THE PUBLIC HEALTH IMPACT OF INTERIM REMEDIAL ACTIONS TAKEN AT THE BLOOMINGTON SITES

ATSDR's response to this issue is summarized in the response to comment #25 and also appears here.

The PHA discusses all of the interim remedial measures (IRMs) and acknowledges that the measures have been effective in isolating the highly contaminated materials and on-site soils so the public cannot come in contact with them. ATSDR does agree that these IRMs have greatly reduced the public's exposure. However, there is also evidence that, even with these interim measures, contamination continues to leach from all of these sites with the probable exception of Anderson Road Landfill, where it appears that all of the PCB-contaminated material was removed.

  • ATSDR'S ROLE AS A PUBLIC HEALTH AGENCY WITH REGARDS TO CONCERNS ABOUT IMPACTS ON WILDLIFE AND THE ENVIRONMENT

From several public meetings and from a few comments received on Volume I (see #11 and #179), it appears that some misunderstanding remains about ATSDR's role regarding the Bloomington sites. The response to comment #11 addresses this question, and the answer also appears here.

ATSDR, as a public health agency within the Department of Health and Human Services, is mandated by law to address issues related to human health. Other federal agencies, such as the Environmental Protection Agency (EPA), and state agencies have mandated responsibility for evaluating impacts of pollution on wildlife and ecosystems. ATSDR does, however, consider situations where plants and wildlife (animals and fish) that may serve as sources of human food become contaminated and under certain circumstances could lead to human exposure and perhaps adverse health effects. ATSDR is, therefore, concerned primarily about effects of the wildlife on public health.

  • "CONSERVATIVE" TOXICOLOGIC AND EXPOSURE ASSUMPTIONS SHOULD NOT BE USED IN THE PHA PROCESS

ATSDR is a public health agency whose mission is to prevent exposure and adverse human health effects and diminished quality of life associated with exposure to hazardous substances from waste sites, unplanned releases, and other sources of pollution present in the environment. Because of this important role, ATSDR often uses conservative assumptions in the initial steps of its assessment process to assure that a more detailed evaluation of data and information is conducted. Thus, ATSDR views the use of conservative assumptions as appropriate when they are used as a screening device. Final decisions regarding the nature and extent of a public health hazard are determined by professional judgement based on an evaluation of measured or estimated levels of exposure and an assessment of the related toxicologic and epidemiologic information for the contaminants of concern. Where sufficient data to make health decisions are available, the tendency is to reach conclusions that exhibit less conservatism. Where data are judged to be incomplete, the tendency is to reach conclusions that have greater amounts of conservatism built in. Because of the interest and public concern that were focused on these sites, ATSDR encouraged the ISDH to use conservative assumptions to assure that no exposure pathway or health hazard was missed. (See responses to #28, #41, #82, #121, #130-#132, #134, #155, #156, and #187).

III.B. Responses to General Public Comments on the Public Health Assessment for Bloomington PCB Sites, Volume I

#1.    In general, what was available were summaries, not laboratory reports including quality control data. There was no way to rigorously evaluate the data quality from the supplied laboratory reports and summary, yet the assessment continually attempts to remark on the quality. If the data made available was similar to what Westinghouse compiled, there was no possibility of an adequate assessment of data quality. Superfund health risk assessments demand a complete data accumulation of high quality information. The inability to support the data used in this assessment with a good quality assurance procedure, considerably weakens it. The proper procedure is discussed below. (See comment #2 below.) Until ATSDR can supply the supporting documentation to prove that an adequate site characterization was accomplished, this assessment is premature, and unreliable.

    The ATSDR PHA process does involve determining the validity and the quality of environmental, food chain, and human biological data prior to their use in a PHA. The decision to use or not use data is always made with the knowledge of the question or questions being asked and a clear acknowledgment and statement of the limitations of the data.

    ATSDR agrees that the site characterization data for many of the Bloomington sites are very limited. However, site characterization data and information are only two of several important sources of information that we need to consider when evaluating public health. In fact, the most critical data and information for assessing impact on public health are related to the nature of activities that bring humans in contact with contaminants on site and off site. If human contact is frequent and continuous or otherwise judged to result in likely significant exposures, then the quality and nature of the site characterization data become very important. However, if likely exposure patterns do not meet these criteria, then the quality of the site characterization data may not be so important for the judgement of public health impact. For many of the areas in Bloomington, ATSDR staff members believe that we can make public health judgements based on likelihood of exposure despite the lack of environmental data or the poor quality of existing data. Recognizing that environmental data are collected for various purposes, including the selection of remedial options, ATSDR routinely asks for data that will be relevant to judging the kinds of exposures individuals might receive. Additional environmental sampling should fill data gaps for those areas where human exposures are feasible to ensure that protective measures are in place and to permit analysis of the impacts of past exposures. The kind of data that ATSDR needs for human or public health assessment, however, may not be relevant to the development of site remedial options or to limiting ecological impacts.

#2.    The acceptability of what is referred to by the EPA as "the functional equivalent" of an RI/FS (remedial investigation/feasibility study) for risk assessment depends on its variance from the standard procedure with regards to the characterization of the site and the pathways and degree of exposure of humans with the full extent of hazardous substances. The reliability of the assessment depends on data of appropriate quality. Quality is affected by errors in sample location, sample integrity, and sample analysis. If the data (are) not gathered correctly or (their) quality is not measurable, reliable risk assessments are not possible.

To obtain data of appropriate quality and representative of the site requires a quality assurance project plan (QAPP) and a field sampling plan (FSP). This approach is designed to yield adequate information on the identity, concentration range, and extent of occurrence of hazardous substances and routes of potential environmental and health impact. Because no Project Plan containing the necessary site characterization and data quality assurance plans (exists), a risk assessment based on data collected without them is unlikely to be reliable. Considering that these documents were not prepared before the work began indicates that a site characterization and risk assessment does not formally meet the RI/FS requirements. Further, because these performance documents are not assembled in some form to support this accumulation of data collection, indicates that neither ATSDR or EPA can support use of the data as a "functional equivalent." This type of site characterization data is exactly what EPA (the Environmental Protection Agency) was intending to prevent with the RI/FS procedures.

To support the usability of data for site characterization or risk assessment, the quality of the data must be verified with standard procedures for analysis. These standard procedures established in the EPA's Contact Laboratory Program (CLP) Statement of Work for data collection under CERCLA (the Comprehensive Environmental Response, Compensation, and Liability Act), or with RCRA (Resource Conservation and Recovery Act) methods (SW-846) require analysis of an adequate number of quality control samples along with the site samples. These results should always be attached or associated with the analytical results to give a measure of the detectability, accuracy, and reproducibility of the sample results. The reports made available do not have this information. If the requisite QC (quality control) was not performed, the data are unusable; if the QC is not available, the usability of the results is unjustifiable. For the most part because adequate QC results were not included with laboratory reports, this indicates that they were not done, and therefore the data used for the site characterization does not appear to be reliable. Conclusions as to the identity and extent of contamination, and potential risks are incalculable.

The unreliability of the data collection and quality are clear in the report that ATSDR and the Indiana State Department of Health (ISDH) have prepared. Even rudimentary attempts at QA (quality assurance)/QC evaluation reveal ISDH/ATSDR's unfamiliarity with the CLP data evaluation procedures. For example, the disregard of results for a large number of contaminants detected at Neal's LF (Landfill) (plO4, 1st paragraph, section C) is not justifiable simply because of low concentration and reproducibility. At levels close to the detection level, it is not unusual to lose the ability to reliably quantify a detection. (This is also the purpose of the CLP "J" marker which the users were apparently unfamiliar with.) Additionally, assessment criteria are established in CLP for evaluation of laboratory contaminants. The suspected contaminants will also show up in the QC samples, and the levels are similar. Because these sites are landfills, common solvents and plasticisers are very likely to occur. To dismiss evidence for major contaminant releases in a health assessment without sufficient justification is specious (and suspicious).

    See response to #1

#3. In general the document reads as a downplay of the situations and threats at these sites. By not criticizing the quality and usability of the data and very much qualifying the report with a strong statement concerning data gaps, fundamental flaws in the site characterization process are accepted. Further, important data is eliminated or ignored. Whether done by accident or intent, it serves to minimize the risk. The report gives the impression that a quality assessment was accomplished and few serious health threats exist.

    See response to #1.

#4. At all sites a concern for the inadequacy of the site characterization data as is weakens the quality of the health assessment.

    See response to #1.

#5. The absence of an ATSDR toxicological profile does not constitute grounds for implying little threat. There are other sources of toxicological criteria usable to express a more definite level of risk.

    We agree. All sources of information are used and considered. The fact that an ATSDR toxicological profile may not be available doesn't preclude an evaluation of the hazard posed by a substance in a completed pathway identified for a site.

#6. The PCB contamination at the Winston-Thomas lagoon is being carried off site by ducks and turtles. Migrating fowl are over the FDA (Food and Drug Administration) limit for PCBs. Emergency action is needed.

    There has been concern expressed that hunters in the Bloomington area, as well as elsewhere, could be exposed to PCBs (and other contaminants that have not been identified) as a result of consuming game animals and migrating ducks that spent time at the Winston-Thomas site. The Fish and Wildlife Service (FWS) has found that ducks spending a limited time in the lagoon very quickly accumulate PCB body burdens in excess of 3 parts per million (ppm), the FDA tolerance level for poultry. While exposure to PCBs as a result of consuming such ducks is a feasible pathway of human exposure, ATSDR believes it is unlikely that individuals would consume enough of these ducks to pose either short-term or long-term adverse health effects. This is especially evident if the frequency of ingestion over a lifetime is compared to the frequency of ingestion of commercial poultry. Thus, anticipated human ingestion patterns of ducks that may have spent time at Winston-Thomas would not be expected to increase human body burdens of PCBs, nor would there be a significant likelihood that adverse health effects would result from the occasional consumption of such wildlife. On the other hand, there is a much greater likelihood that the ducks, including their offspring, and other species that use the lagoon may be adversely affected, depending on the levels of PCBs accumulated. ATSDR recommends that an appropriate local or federal agency evaluate the latter possibility.

#7. The phrase "background body burden of PCBs is 20 ppb (parts per billion)" should not be used. Before 1929 this background level was impossible. The commenter believes that sublethal doses (background levels) are causing strange reproductive or carcinogenic effects in the population.

    The commonly cited background body burden level of 20 ppb PCBs is used as a reference value for comparison to populations with no known site-specific exposure to PCBs. It represents the upper 95% confidence interval of the distribution of serum PCB levels from a sample of the general U.S. population. The causation of cancer and reproductive effects from exposure to PCBs at background levels has yet to be documented.

#8. Although U. S. EPA Region 5 does not dispute ISDH's conclusions regarding its assessment of exposure, the portrayal of exposures presented in this summary may lead the readers of this document to conclude that the current or future exposures of contaminants associated with the PCB sites are very low. It is important for readers of this document to recognize several relevant facts. First, during the late 1980's, interim corrective measures were undertaken at each of the PCB sites to reduce actual and potential exposures to harmful contaminants and to reduce the migration of contaminants from the sites. The corrective measures taken were intended to protect human health and the environment until a final remedy could be implemented. Existing information supports the understanding that the PCB sites currently contain substantial quantities of PCBs. Further, the geologic settings at several of the PCB sites are not consistent with the type of containment that provides reliable protection from contaminant migration. In fact, migration of contaminants from several of the sites has been conclusively shown.

Second, although a substantial volume of information related to the PCB sites exists, the available data is insufficient to adequately determine the types, amounts, or location of the contaminants at the sites. In addition, the karst topography in Bloomington makes a precise characterization of contaminant migration from the sites difficult to determine.

    We agree. The reader should not interpret this document to say that these sites need no further remediation. The interim measures have for the most part isolated the highly contaminated materials, so the public is not exposed to them. However PCBs continue to leach from the sites and contaminate the springs, streams, and groundwater, which could affect humans but more likely will affect wildlife. It will be necessary to watch vigilantly and sample routinely all the springs and creeks and fish in them associated with these sites to identify areas that need re-posting to keep the public's exposure at a minimum until the sites are remediated. Groundwater plumes in areas where the nearby residents use private wells should be delineated. ATSDR agrees with EPA that the karst geology makes it difficult to determine the contaminant migration. Therefore, ATSDR has recommended that, where appropriate, nearby residential wells be routinely monitored to assure that their water supply has not become contaminated.

#9. It is difficult to imagine that experienced as ATSDR is in reviewing, and using RI/FS data that some better guidance could not have been given to the preparer's of this assessment. ATSDR probably should not have depended on an outside party to do its work.

    The ISDH wrote Volume I of the PHA as part of a cooperative agreement between ISDH and ATSDR. Under this cooperative agreement, the state health department uses the ATSDR PHAGM as a guide to prepare the PHA. ATSDR then reviews and approves the PHA. ATSDR has PHA cooperative agreements with 22 state health departments. As the response to the final theme in Section III.A. reports, ATSDR encouraged the ISDH to use conservative assumptions to assure that no exposure pathway or health hazard was missed. Accordingly, ATSDR believes the ISDH did its job very well.

#10. The data the state of Indiana and ATSDR uses is wrong because a site characterization was never done. You are making health risk assumptions on faulty data. Quit supporting incineration when it does not apply to Bloomington. Require Westinghouse to do site characterization.

    See response to #1 with regard to data quality and completeness. Concerning the alleged support for incineration, ATSDR has not taken any position regarding remedy selection for these sites. However, ATSDR will, if asked, comment on the public health implications of any proposed remedy or remedies for each site. The consent decree parties are revisiting each site to determine what additional data and information are necessary to help them select the most appropriate remedial action. These data may help evaluators fill environmental data gaps and determine what public health actions, if any, are needed during remedial activities or to protect the public and the environment from further exposure.

#11. ATSDR is not concerned about wildlife.

    From several public meetings and from a few comments received on Volume I (see also #179), it appears that some misunderstandings remain about ATSDR's role regarding the Bloomington sites.

    ATSDR, as a public health agency within the Department of Health and Human Services, is mandated by law to address issues related to human health. Other federal agencies, such as EPA, and state agencies have mandated responsibility for evaluating impacts of pollution on wildlife and ecosystems. ATSDR does, however, consider situations where plants and wildlife (animals and fish) that may serve as food for humans become contaminated and under certain circumstances could lead to human exposure and perhaps adverse health effects. ATSDR is, therefore, concerned about wildlife, but primarily in ways that may affect public health.

#12. The data for the sites is inadequate.

    See response to #1.

#13. All of the contaminated streams need to be posted at the bridges.

    The ISDH is responsible for issuing fish advisories and for posting appropriate locations. ISDH representatives have indicated that they will ensure that advisories are posted at appropriate locations relating to all appropriate site-related creeks, streams, and springs.

#14. We are concerned about food chain contamination.

    See response to #6.

#15. In addition to dumping imperfect and used capacitors filled with PCBs in many dumps or landfills, Westinghouse is known to have dumped large quantities of the solvent trichloroethylene in Neal's Landfill.

    Results of 1982-1983 sampling activity indicate that trichloroethylene was present in high concentrations (25,700 ppb) in groundwater beneath Neal's Landfill (see page 95 of Volume I of the PHA). During the same time period, off-site stream levels were also considerably elevated (maximum of 56 ppb) (see page 99 of Volume 1 of the PHA). Data on current levels of trichloroethylene and other volatile organic compounds (VOCs) were not available to assessors preparing the PHA. However, ATSDR believes as noted in response #1 that the nature and extent of feasible human activities and contact with surface waters for many of the sites, including Neal's Landfill, are such that they are unlikely to result in exposures that affect human health. The consent decree parties are evaluating the sites for remedial options.

#16. While the public can comment and have "input" ad infinitum, it is meaningless if not at a meaningful point in the decision making process. USEPA refused to prepare either an RI/FS or EIS (environmental impact statement) which deprived us of a scientific study and analysis of the types and scope of contamination at the Superfund sites, and of status which comes from written documentation of public concerns and preferences of alternatives considered for the cleanup. What we got in a consent decree was Westinghouse, the polluter, having the right to decide what technology, and even what type of incinerator would be used for the cleanup, a Westinghouse/O'Connor rotary kiln.

None of the Monroe County/City of Bloomington (MC/CB) Superfund (NPL [National Priorities List]) Sites nor other CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act of 1980) sites have had NEPA (National Environmental Policy Act) nor RI/FS site characterization studies to determine the size and scope of contamination by PCBs, other organochlorines, heavy metals, etc. Such studies are required under NEPA and CERCLA and are essential for discussion and decision-making on methods and technology for disposal of hazardous wastes.

    See response to #1. The consent decree parties are reevaluating remedial options.

#17. The Fish & Wildlife Service Report of January 25, 1994, sent to Dr. Greg Steele, Indiana State Board of Health, on containment of the Superfund Sites in MC/CB was also sent to ATSDR in February, with an accompanying letter. This is a highly significant document and I would appreciate consideration of this report in any evaluation that ATSDR makes of the Bloomington hazardous waste situation. As noted by the FWS, much of the data in the ATSDR PHA is of questionable value, due to the superficial nature of the sampling efforts, lack of adequate sampling design to ensure representativeness, and undocumented quality assurance information. ATSDR and ISDH should point out these deficiencies in the record upon which they based their studies, and call for scientific site characterization studies to give a measure of validity to further analyses of the sites. The FWS letter points out that "probably the most compelling weakness (in the ISDH Report) is the general lack of dioxin and furan data throughout these sites, especially where burning was known to occur."

    ATSDR did review the FWS letter and found it to be a valuable source of information. See responses to #6, #59, #135, #153, #164, and #177.

#18. EPA and Westinghouse have consistently underestimated the size of the PCB sites, a fact which citizens pointed out upon public release of the estimates. We do not know the amount of hazardous waste remaining unexcavated under the Plastic Storage Bag that contains the excavated wastes of the Fell Iron & Metal Site in situ, but the total cubic yards is likely to be three times the estimate made in the Westinghouse-funded study prior to excavation.

The public learned recently that EPA had increased its estimate of the extent of contaminated soil at Lemon Lane Landfill from approximately 176,000 cubic yards. The present estimate is more for one single site than EPA and Westinghouse had estimated for all six Superfund sites in the consent decree!

ATSDR must correct the "more than 650,000 cubic yards" estimate on pages 3, 4, and 77 of its PHA for Bloomington PCB Sites, Volume II of II and wherever else warranted in its publications on the Bloomington PCB Project. ATSDR should also try to obtain more accurate estimates of other Superfund sites for its health effect studies, particularly Neal's Landfill and Bennett's Quarry which citizens believe to be equally underestimated.

    The consent decree parties are reevaluating the sites and may obtain additional environmental data. Any new data, however, are not likely to affect the potential for human exposure under existing or future conditions. See also response to #10.

#19. The toxic substances on the PCB sites have not been effectively contained as ordered under the consent decree and the sites continue to be significant health threats to the MC/CB community and the environment.

Region V EPA has given priority to remediating Lemon Lane Landfill. While this is long overdue--all of the sites should be on the critical list and the Winston-Thomas Lagoon with its ambient air pollution and long-term contamination of wild game and other animals, needs as immediate remediation as does Lemon Lane.

The record shows that the consent decree parties literally turned their back on the continuing health threat of these sites to the MC/CB community, with virtually no scientific testing and evaluation of the effectiveness of the so-called "remedial actions" which they had performed. The runoff during even moderate rains from Neal's Landfill is a scandalous situation.

    See responses to #8 and #25.

#20. ATSDR must consider US EPA's Dioxin Reassessment as it relates specifically to MC/CB's specific situation. The most significant information in the dioxin reassessment is that the average person in the U.S. is exposed to daily doses of dioxins which are within one order of magnitude of those expected to give rise to dioxin's most sensitive effects. The current exposure to dioxins is too high, which is reason enough to ban incineration and phase out existing incinerators.

    See responses to #82 and #110.

#21. The report's purpose is to evaluate the public health impact of six sites in Monroe County, Owen County, and Bloomington, Indiana. This evaluation is performed by the analysis of past, present and future human exposure pathways. This report is not balanced in its treatment of the exposure pathways. Much emphasis is placed on past PCB exposure associated with the uncontrolled consent decree sites, that is, before the interim remedial measures were completed.

    The commenter accurately reflects the purpose of the PHA, which is to evaluate past, present, and future exposures. That the assessment appears to emphasize past exposure is largely due to the fact that for many areas historical data were the only data available to the assessors. These data were therefore used to form the basis of the assessment of potential past exposures. Since much of the environmental data and information on human activities that would affect exposures are limited and not current, it is difficult to reach definitive conclusions regarding the potential impact of current contamination on human populations. As noted in the PHA, past exposures were likely to have occurred among segments of the population. While present exposures appear to be minimal because of the interim interventions, future exposures may still be possible, depending on the degree of continued effectiveness of the interim measures. Exposures during remediation may also be feasible, and preventive measures must be considered in remediation plans. These concerns are noted in both volumes I and II of the PHA.

#22. Westinghouse does not agree with some of ATSDR's conclusions. Westinghouse trusts that ATSDR will consider these substantive comments which are resubmitted herein and will be factored into the final Health Assessment Report.

    We have reviewed and considered all comments and factored them into the final conclusions and recommendations.

#23. The report places undue emphasis on past exposures. The primary focus of the report is on "past" exposures. ATSDR's stated purpose in discussing past exposures is to identify those groups that may have been maximally exposed to the sites so that these groups may be further studied and monitored for indicators of exposure and potential adverse health effects. In Bloomington, however, these groups (workers and scavengers) have already been identified and studied. Available epidemiological data from several studies of these groups indicate no significant health effects. Other than workers, there are no data that suggest that Bloomington residents are any more exposed to PCBs than the general U.S. population.

    Regarding past exposures, see response to #21.

#24. The report draws conclusions regarding potential adverse health effects that are contradicted by available evidence. This report states that the health of specific subgroups may have been adversely affected, while at the same time presenting contradictory evidence. ATSDR/ISDH states that specified subgroups "may be exhibiting signs and symptoms of adverse health due to site-related exposures." However, as discussed above, health studies cited in this report conclude that this is not occurring. In fact, the report states that the populations identified as potentially maximally exposed (scavengers and trespassers) have no indications of elevated exposure, much less any indication of adverse health effects.

    ATSDR does not agree with either of the commenter's conclusions: (1) health studies have not shown a health impact on subgroups, and (2) maximally exposed subgroups (scavengers and trespassers) have no indications of elevated exposure. The major emphasis of studies on the subgroups has been on exposure, not on health effects. Also, the analysis of health outcome data had to focus on the entire populations of the counties and not on the specific subgroups. The statement that exposures to scavengers and trespassers did not result in increased body burdens of serum PCBs is based on mean rather than individual values. Data in Table 55 on page 156 show that individuals in the scavenger category had serum PCB levels up to 51 ppb, well above the reference value of 20 ppb. Therefore, some of the scavengers did have measurable elevated exposures to PCBs.

#25. The report fails to acknowledge the effectiveness of interim remedial measures (IRMs). The IRMs implemented at the sites have effectively limited exposure, but the report does not accurately reflect this fact. Remedial measures included capping Bennett's Stone Quarry, Lemon Lane Landfill, and Neal's Dump, as well as removing sediment from Clear Creek near the Winston-Thomas Facility. These measures were conducted in accordance with the consent decree, and have effectively eliminated exposure pathways for on-site soil and groundwater, as well as the possibility of contact with Clear Creek sediments. The report fails to consider these IRMs and identified potential exposure pathways which are no longer possible, e.g., volatilization and dust generation from on-site soils at capped sites and exposure to sediments that have previously been remediated. The report should consider only post-IRM conditions and post-IRM data in evaluating current and potential future exposures at the sites.

    The PHA discusses all of the IRMs and acknowledges that the measures have been effective in isolating the highly contaminated materials and on-site soils so the public cannot come in contact with them. ATSDR does agree that these IRMs have greatly reduced the public's exposure. However, there is also evidence that, even with these interim measures, contamination continues to leach from all of these sites with the probable exception of Anderson Road Landfill, where it appears that all of the PCB-contaminated material was removed.

#26. The report presents unsubstantiated exposure scenarios. Many of the exposure pathways and scenarios identified in the report are suspect. The report lists any pathway which it cannot definitively eliminate as a potential pathway. In doing so, the report does not follow its cited guidance which states that five key elements must be present for a pathway to exist, but many of the exposure pathways identified in the report lack one or more of the five required elements. In addition, many land uses and practices cited in the report are based on anecdotal and unsubstantiated information. For example, the report identifies consumption of wild game taken on site as a completed exposure pathway for Lemon Lane Landfill in the present and future. However, post-IRM conditions (plastic cap and fencing) eliminate any potential for game to be exposed on site. In addition, there is no information that people hunt wild game within city limits or that anyone has in fact hunted or consumed wild game from the site. As a second example, the report's estimate that 300 children are regularly exposed to Illinois Central Springs is a gross overestimate considering the small size of the area and the fact that it cannot support fishing or swimming.

    The commenter's observation is correct that several pathways were identified as potential when the health assessors could not eliminate at least one of the five required elements of a human exposure pathway. ATSDR guidance (page 6-33 of the ATSDR PHAGM) states that "A suspected pathway can be eliminated if at least one element, which would link the five elements, is absent and will never be present." Stated differently, a pathway cannot be eliminated unless one of the five elements has never been present or will never be present.

    With regard to Lemon Lane Landfill, human consumption of wild game obtained from on- and off-site locations is considered completed past, present, and future exposure pathways. Page 69 of the PHA indicates that ISDH staff members had discussions with individuals who reportedly have consumed and are consuming game from areas associated with the site. In addition, the report does not state that "300 children are regularly" exposed at the springs. The report does indicate that there are 300 residences near Lemon Lane and that ISDH has received reports that children regularly play at the springs (see page 71). Because of these reports and because of a lack of data to suggest that exposures at the spring areas as a result of a number of different activities does not occur, such exposures are deemed potential as indicated in Table 21, page 72. The 300 represents a maximum estimate, not a regularly exposed estimate. ATSDR does agree with the commenter, however, that there is a need to obtain and evaluate data and information regarding fishing practices and recreational activities for these areas.

#27. The report ignores available monitoring data and site information that indicate lack of exposure. The report fails to use pertinent site information (e.g., groundwater flow patterns) which would affect the pathway analysis. For example, the report states that exposure via off-site groundwater may occur at several sites. However, available potable well data and groundwater monitoring data for the sites show that no exposure is occurring through this pathway. As another example, the report finds that consumption of fish caught in Stout's Creek may present a health problem, but no post-IRM data are cited for Stout's Creek fish. As a third example, the report identifies application of sludge to gardens as a completed present and future exposure pathway for the Winston-Thomas site, despite the fact that this practice no longer occurs.

    The health assessors reviewed and cited all pertinent data and information available to them. A PHA contains reviews of past and present data that help assessors determine the likelihood of past, present, and future human exposures to contaminants. If current monitoring data show that private well water and post-IRM fish are not contaminated or that human access to site-related contaminants is not occurring, assessors can conclude that no current exposures are occurring. This does not rule out the possibility of past or future exposures. For example, although the practice of using PCB-contaminated sewage sludge no longer occurs, persons who still garden in areas where sewage sludge was applied are still at risk of exposure. Thus, the exposure pathway involving sewage sludge is considered to represent a past, present, and future source of exposure. Unless additional sampling is conducted to determine the present levels and extent of contamination in these gardens, assessors will assume that contamination is still present and that exposures have occurred, are occurring, and will continue to occur to individuals who come in frequent contact with such areas or who consume vegetables grown in those gardens. Assessors can determine the extent of potential exposure by characterizing the levels of soil contamination and obtaining information about crops grown and consumed in these soils.

#28. The report uses questionable screening criteria to evaluate the potential for adverse health effects. This report uses inappropriate screening criteria (minimal risk levels [MRLs]) to evaluate chemical data and exposures. The screening criteria were derived using generic exposure assumptions which do not accurately reflect site-specific conditions. In fact, the PCB screening level used to evaluate groundwater data in this report is 10-fold less than the USEPA drinking water standard for public water supplies. Furthermore, the toxicological data used to derive the screening values have not been formally endorsed by USEPA, nor were these data endorsed by the ATSDR Health Effects Panel convened in Bloomington.

    The commenter is correct in stating that we used generic (not site-specific) exposure assumptions as comparison values (CVs) or screens. ATSDR uses generic, media-specific screening values to select contaminants for further discussion in the health assessment and to ensure that ATSDR and state-based health assessors review closely all pertinent site-specific and chemical-specific information for substances they choose for further discussion. Definitions and generic procedures for deriving and using media-specific CVs (such as ATSDR's EMEGs--environmental media evaluation guides) appear in Appendix D of the ATSDR PHAGM. These media-specific CVs and the ATSDR MRLs for non-cancer endpoints that form the basis of ATSDR's EMEGs do not require EPA endorsement. Thus, using CVs as screening tools is certainly within the scope of the PHA process.

    ATSDR's Toxicological Profile on PCBs contains a discussion of the basis for choosing the oral MRL used to derive ATSDR's EMEGs for soil and water. The health panel did not discuss either the EMEGs or the MRLs. Furthermore, the health panel concluded that there is a need for additional data to determine the impact of PCBs on the immune system, which was the endpoint used as the basis for the MRL. Unless there are conclusive human or animal data to suggest otherwise, ATSDR uses the most sensitive endpoint observed in the most sensitive animal species tested to determine an MRL. ATSDR considers the current MRL and CVs appropriate for screening purposes.

 

#29. The report incorrectly identifies ambient air as an exposure pathway. ATSDR/ISDH included exposure to ambient air as a potential exposure pathway at Lemon Lane. The report also makes statements about "compromised" air quality in the Illinois Central Springs area, but does not provide any data to support these statements. In fact the IRM cap at Lemon Lane effectively eliminates any potential for significant volatilization or dust generation, a fact that is reflected by available PCB air monitoring data.

    Ambient air was considered a component of past completed exposure pathways for on-site and off-site locations. The designation as a component of a potential pathway for off-site locations was based largely on the lack of data to confirm that levels of PCBs (and other contaminants) are not elevated. Reports of compromised air quality following major rainfall events cannot be ignored, although ATSDR's experience would suggest that levels of PCBs in air from these areas would likely be minimal (nondetectable). See response to #26 regarding potential pathways.

#30. Even though the report used extremely conservative and unrealistic assumptions, the ATSDR/ISDH health assessment shows (1) there are no adverse health impacts associated with the sites; (2) the remedial measures conducted at the sites were successful; (3) the remedial measures at the site have effectively limited potential exposure pathways to the groundwater pathway; and (4) this potential pathway is well characterized, is not a threat, and can be periodically monitored for PCBs to affirm that conditions at the sites remain protective of human health and the environment. Each of these points is discussed in more detail below. Westinghouse, in conjunction with governmental environmental agencies, continues to study and monitor the sites. The results of these monitoring programs are regularly used to examine potential environmental pathways of human exposure. As expected, the characterization studies and environmental pathway analyses of the sites in their current state suggest that there are no public health implications associated with the sites.

Here are our major points of agreement:

    (1). The ATSDR/ISDH data review shows that there are no instances of increased human exposure, much less adverse health impacts, associated with the disposal sites.

This conclusion is based on the health studies conducted in Bloomington and Monroe County that were reviewed in the pathway analyses report. The health studies reviewed in the report can be separated into two categories: those applying to Westinghouse plant workers and those applying to the general population of Bloomington, especially those living near the disposal sites. With regard to workers, the studies have not demonstrated any clear health effects due to PCBs, despite the fact that some of these workers have serum PCB levels many times greater than the general population. Serum PCB levels are indicative only of exposure and do not reflect actual health impacts. The studies on workers concluded that "No clinical abnormalities attributable to exposure to PCBs were observed" (page 158 - Volume 1).

With regard to Bloomington residents living near the sites, the multiple studies conducted show that these people are no more exposed to PCBs than the general U.S. population and concluded that "in spite of the potential for exposure to PCB-contaminated media, individuals living in the general community were generally not at risk of exposure" (page 157 - Volume 1). The ATSDR/ISDH report concluded for each of the sites that "Community-specific health outcome data do not indicate that the site has had an adverse impact on human health" (pages 164-168 - Volume 1). The report also recognizes that the health studies have shown that for the population potentially most exposed to PCBs, such as scavengers and trespassers, "that such exposures do not result in increased body burdens of serum PCBs" (page 147 - Volume 1). In summary, these studies demonstrate that people living near the disposal sites have not experienced increased exposure to PCBs, much less any PCB-related health effects.

Although the purpose of the report is not to deal with plant workers and is to be limited to possible exposure to the general community from the six consent decree sites, these studies are nevertheless useful in the analysis of health impacts.

    As noted in responses to #21 and #24, ATSDR does not agree that there are no instances of increased exposure among Bloomington residents. Documented past elevated exposures to segments of the area population have occurred. ATSDR recognizes that existing epidemiologic studies have not demonstrated a causal relationship. Several associations identified among occupationally exposed individuals, however, do bear continued monitoring. For example, the existing historical cohort mortality study of workers showed a statistically significant increase in deaths from malignant melanoma and a moderate, though not statistically significant, increase of brain cancer. Thus, ATSDR cannot say with certainty, as suggested by the commenter, that no adverse health effects have occurred or will occur.

    These county-wide data may have not yielded information that would have allowed assessors to identify medical symptoms and signs of adverse health outcomes due to site-related exposures to specific subgroups of people.

    (2.) The remedial measures conducted at the sites by Westinghouse were successful. The importance of the remedial measures already completed at the sites cannot be understated, and their success is documented by this health assessment report. Based on the conclusions in the ATSDR/ISDH report, it is evident that the remedial measures undertaken at the sites, primarily by Westinghouse, are protective of public health and the environment. These activities were completed in cooperation with and (with) approval from the government consent decree parties. Maintenance of the sites began in 1985 and continues today. Westinghouse personnel routinely perform extensive monitoring and conduct inspections at all sites at least monthly to assure there has been no site disturbance and to verify that the security fences and caps are intact.

The highest concentrations of PCBs in site soils were found in surface soil adjacent to leaking capacitors. Remedial measures have effectively eliminated the potential ambient air and on-site soil exposure pathways. These measures included the removal of 20,000 pounds of capacitors plus surrounding "hot spot" stained soils from the sites; the installation of caps/cover at Lemon Lane Landfill (9.5 acres), Neal's Landfill (17 acres), Bennett's Dump (3 acres) and Neal's Dump (one-half acre); and installation of perimeter fencing around the sites.

Off-site sediment and surface water pathways have been virtually eliminated through the removal of soils and sediments along 2.5 miles of streams and creeks in the vicinity of the sites. The caps also limit direct surface water runoff contact with site soils. In addition, the installation and continuous operation of the Spring Treatment Facility at Neal's Landfill has prevented the recontamination of Conard's Branch and Richland Creek as demonstrated by the most recent sampling data.

In addition, Westinghouse completed removing PCB-bearing materials from a sixth consent decree site, the Anderson Road Landfill, in 1987. The USEPA and the Indiana Department of Environmental Management (IDEM) have agreed that this site requires no further monitoring, and it has been returned to its original use as Monroe County's landfill.

    See response to #25.

    (3.) The remedial measures conducted at the sites have effectively limited potential exposure pathways to the groundwater pathway.

This report confirms that the remedial measures taken at the sites have effectively eliminated most pathways of exposure. The reduction in potential exposure pathways associated with each of the sites was established by the data evaluation in the environmental pathway analyses which indicates that groundwater pathway is the primary present and future potential route of exposure. For each of the sites, this pathway is well characterized. Based on the most recent data, groundwater at each site is free of PCBs or has very low concentrations present. Moreover, the residential drinking wells near the sites are not affected.

Environmental investigations show that remedial measures have significantly reduced or eliminated the potential for PCB exposure from surface waters, including Conard's Branch, Richland Creek, Stout's Creek and Clear Creek. These waters have either been found free of PCBs or have very low concentrations, less than 1 ppb. In addition, the data shows that environmental protection measures, including sediment removal from Conard's Branch, Richland Creek, Stout's Creek and Clear Creek have significantly reduced or eliminated potential PCB exposures (samples ranged from nondetectable to 1.8 ppm) from this medium.

Groundwater subject to influence of Lemon Lane Landfill discharges at Illinois Central Springs and Quarry Springs. While sampling has found detectable levels of PCBs in these waters for approximately 1500 feet, the springs are not used as potable water. Moreover, the springs are in isolated areas, and neither spring discharges into surface waters used as potable supplies. A fence and warning signs surround Illinois Central Spring restricting access to the spring water. At Neal's Landfill, a Spring Treatment Facility collects and treats flows from North Spring, South Spring and Southwest Seep. These factors combine to make exposure to PCBs from springs negligible.

    See responses to #8 and #25 regarding continued leaching and insufficient information regarding private wells.

    (4.) The potential groundwater pathway is not a threat and can be periodically monitored for PCBs to affirm that conditions at the sites remain protective of human health and the environment. The environmental remediation and site security measures summarized above, coupled with the health and safety measures employed by site maintenance personnel, effectively eliminate the potential for on-site PCB exposure. Westinghouse and government agencies have found low concentrations of PCBs in site groundwater monitoring wells. However, these concentrations are either well below drinking water standards or not in potable water well zones. Significantly, water analyses of private residential drinking water wells near the sites have never detected PCB concentrations above the safe water drinking standard (MCL [maximum contaminant level]) of 0.5 parts per billion. The report concluded for each of the sites that "Community specific health outcome data do not indicate that the site has had an adverse impact on human health" (pages 164-168 - Volume 1). Furthermore, extensive groundwater investigations have provided information on groundwater flow paths and indicate drinking water wells are not impacted. Understanding the groundwater regimes enables the development of a groundwater monitoring program that will affirm that the conditions at the sites remain protective of the public health and environment.

    As noted in response to #25, ATSDR agrees that the interim measures have been effective in limiting and largely preventing human exposures. However, off-site migration of contaminants via groundwater is still occurring at several sites. Thus, ATSDR supports continued monitoring of areas where human exposures and ecological impacts may occur. Monitoring remains an important component of an interim strategy to protect human health and the environment, particularly given the existing karst geology, which makes accurate characterization of groundwater movements difficult to determine.

#31. In Westinghouse's opinion, the four points discussed above represent the principal conclusions of the ATSDR/ISDH report and support Westinghouse's contention that the sites pose no significant threat to human health. These points are not clearly stated or given proper emphasis in the ATSDR/ISDH report, however.

In conclusion, the ATSDR/ISDH health assessment shows (1) there are no adverse health impacts associated with the sites; (2) the remedial measures conducted at the sites were successful; (3) the remedial measures at the site have effectively limited potential exposure pathways to the groundwater pathway; and (4) this potential pathway is well characterized, is not a threat, and can be periodically monitored for PCBs to affirm that conditions at the sites remain protective of human health and the environment. Westinghouse Electric Corporation, in conjunction with governmental environmental agencies, continues to study and monitor the sites to provide for the protection of human health and the environment. Westinghouse stands ready to support ATSDR in this endeavor; Westinghouse's concern is that its comments be given equal consideration with the government agencies' comments and that if the comments are not incorporated that a complete and thorough explanation of ATSDR/ISDH's position and supporting rationale be provided.

    Although there may be some points of agreement, ATSDR does not fully concur with the above statements for the following reasons:

    (1) Documented past elevated exposures to segments of the area population have occurred. ATSDR recognizes that existing epidemiologic studies have not demonstrated a causal relationship. However, there are several associations that bear continued monitoring. For example, the existing historical cohort mortality study of workers showed a statistically significant increase in deaths from malignant melanoma and a moderate, though not statistically significant, increase of brain cancer. Thus, ATSDR cannot say with certainty, as suggested by the commenter, that no adverse health effects have occurred or will occur.

    (2) The interim actions conducted at the sites have successfully reduced or removed the possibility of human exposure to on-site surface soil contamination and, where applicable, to some sediment contamination. However, off-site migration has occurred and, to some extent, is still occurring. Some human exposure still appears to be feasible. Thus, ATSDR does not consider these interim remedial actions to have eliminated exposure completely from many of the off-site locations where PCBs have migrated. In addition, ATSDR does not maintain that an interim action necessarily protects the public from future exposures, because site conditions may change.

    (3) Contaminated groundwater is still migrating off site at several locations and at several sites. These migrations may be affecting streams and wildlife, some of which may serve as occasional food sources for humans. Questions remain regarding the impact of the migrating contaminant plume on the groundwater used for drinking water.

    (4) Because of the karst topography, ATSDR finds it difficult to believe that groundwater under and around the sites is well characterized. ATSDR does support continued monitoring of private wells for contaminants of concern.

III.C. Responses to Specific Public Comments on the Public Health Assessment for Bloomington PCB Sites, Volume I

#32. Page 1- Summary -- It is stated here and throughout the report that specific subgroups "may be exhibiting signs and symptoms of adverse health outcome due to site-related exposures"; however, the subgroups are not identified nor is there any evidence in the report to indicate that this is true. In fact, there is no evidence that long-term, high-level exposures have occurred, and there is no evidence of adverse health effects in any subpopulations in Monroe or Owen counties. This statement is speculative and misleading given the availability of epidemiologic data that specifically show minimal exposures have occurred, much less any adverse health effects.

Not only have epidemiologic studies not revealed any excess amounts of medical conditions in local residents relative to unexposed populations, these studies have shown that the local residences were not exposed any more than unexposed populations (serum-based PCB levels).

Public water supplies are available in the vicinity of each of the sites except for Neal's Dump. More importantly, a hydrogeologic connection from the sites to private wells has not been demonstrated.

There is repeated mention of depressions around Lemon Lane Landfill that are contaminated with PCBs; however, (there are) very limited data (from 1982) that support these allegations.

    With regard to the results of epidemiologic studies and effects in subgroups, see responses to #23, #24, and #30. See responses to #8 and #25 regarding continued migration of contaminants via groundwater and the lack of information about private well usage in some areas.

#33. Page 2 - Summary -- An investigation of sites in and around the Bloomington area allegedly contaminated by PCBs was conducted by the Ecology and Environment, Inc., Technical Assistance Team contracted by the USEPA (Environmental Protection Agency). The results of the study indicated that "...an apparent threat from PCB contamination does not exist at these sites...". ("Site Assessment Report for Bloomington PCB Sites, Bloomington, Indiana", Ecology and Environment, Inc., February 19, 1991, EPA Region V, Contract Number:68-W0-0037).

There does not appear to be any benefit in conducting congener-specific serum PCB analyses on individuals who have previously had their blood tested for PCBs because of lack of data available from which to draw scientifically sound conclusions.

    The health panel that met in Bloomington stated the following in Conclusion L.: "Investigations are needed to evaluate the merit of collecting planar PCB (congener-specific) data. For most occupational and many community epidemiologic studies, congener-specific PCB levels may not be of sufficient value to justify the expense." Thus, any study protocol that requires congener-specific PCB levels in blood must be well justified. The state justified this suggestion because the serum samples were already available and could be retested for site-related PCBs.

#34. Page 7 through 12 - Landfill Summaries --The tabular summaries for the landfills are misleading and erroneous. The tables unfairly characterize the sites by only providing former contaminant levels. Moreover, the contaminant levels that are presented in most cases only represent the maximum levels of PCBs found in each matrix. The concentrations are not representative of conditions that existed at the sites in the past or conditions that exist at the sites at present. Remedial measures such as surface contaminant removal capping, and fencing have been conducted at the sites to reduce or eliminate potential exposure pathways. The most recent data available more accurately characterize the sites in their present conditions and should be presented. In addition, the estimated volume of material presented for each of sites represents the total volume of material identified in the consent decree as being potentially contaminated with PCBs and should be identified as such.

The term pathway is used liberally throughout the report. However, what is often called a pathway is really an environmental medium. The report should emphasize that an exposure pathway consists of all of the following: a contaminant source and release mechanisms, a receptor population, exposure medium, and exposure point, and a route of exposure.

    ATSDR does not consider the summary tables (pages 7-12) to be misleading. The tables clearly indicate the site size and period of operation; former contaminant levels (on- and off-site); the IRMs taken to reduce human exposures; and the media that are within the completed and potentially completed exposure pathways (past, present, and future). However, these tables are meant only as a convenient summary for the reader. The commenter is correct regarding the differences between environmental media and exposure pathways. An exposure pathway does consist of a source (e.g., landfill) and a release mechanism (e.g., leaching, volatilization); a transport medium (e.g., groundwater, ambient air); a point of exposure (e.g., tap water, playground); a route of human exposure (e.g., ingestion, inhalation); and a receptor (person exposed). The individual site descriptions beginning on page 27 and provided throughout the document do discuss all of the exposure pathway elements for both completed and potentially completed pathways.

#35. Page 9 -- The report incorrectly identifies ambient air as an exposure pathway. ATSDR/ISDH included exposure to ambient air as a potential exposure pathway at Lemon Lane. The report also makes statements about "compromised" air quality in the Illinois Central Springs area, but does not provide any data to support these statements. In fact the IRM cap at Lemon Lane effectively eliminates any potential for significant volatilization or dust generation, a fact that is reflected by available PCB air monitoring data.

    See response to #29.

#36. Page 9 - Lemon Lane Landfill Summary Table. The inclusion of on- and off-site wild game as a completed present and future completed pathway is inappropriate. The landfill has a cover system which prevents exposure of wildlife to the landfill. In addition, the landfill does not provide a suitable habitat for wildlife.

    Although ATSDR tends to agree with the commenter that the landfill itself is not a suitable habitat for wild game, as noted on page 69 of the PHA there is the possibility that wild game could drink and forage in the springs and depressions near this site. Furthermore, because the ISDH representatives have seen wild game in the area during at least one of their site visits, and people have indicated that they do kill and eat game in that area, assessors have chosen to list the consumption of wild game as a past, present, and future completed pathway. See also response to #26 regarding completed and potential exposure pathways. (See ATSDR's conclusion regarding the public health implications of fish and game consumption in the areas impacted by the Bloomington sites, Section II. and Section II.A.)

#37. Page 12 and 167 - Winston-Thomas Sewage Treatment Plant.
The off-site sewage sludge should not be considered an exposure pathway from the Winston-Thomas facility because the off-site sewage sludge is not directly related to an environmental pathway from the facility. If it is considered an exposure pathway, it should not be characterized as completed for the present and future because this sludge is no longer being used for garden applications.

    Although the practice of using PCB-contaminated sewage sludge presumably no longer occurs, persons who still garden in areas where sewage sludge was applied are still at risk of exposure. Thus, the exposure pathway involving sewage sludge is considered to represent a past, present, and future source of exposure. Unless additional sampling is conducted to determine the present levels and extent of contamination in these gardens, it is assumed that contamination is still present and that exposures have occurred, are occurring, and will continue to occur to individuals coming in frequent contact with such areas or consuming vegetables grown in those gardens. Assessors can determine the extent of potential exposure by characterizing the levels of contamination. If available data were overlooked, or if new data become available that may change a conclusion or recommendation related to sewage, ATSDR will be happy to review the information. See response to #26.

#38. Page 13 - Summary of Chemicals of Concern by Site and Media Table. The bases for the chemicals of concern other than PCBs is not clear nor does there appear to be sufficient evidence presented in the report to include the additional chemicals of concern.

  • Anderson Road Landfill -- The subsurface soil potentially contaminated by PCBs has been removed as was the on-site surface water.
  • Bennett Stone Quarry -- The on-site soil has been isolated by the remedial measures such as the day (sic) cap and security fence. The on-site pond sediment has been removed.
  • Lemon Lane Landfill -- The on-site subsurface soil has been isolated by the remedial measures such as the synthetic cap and security fence.
  • Neal's Dump -- The on-site subsurface soil has been isolated by the remedial measures such as the soil cover and security fence.
  • Neal's Landfill -- Releases to on-site ambient air are minimized by the remedial measures such as the clay cap.
  • Winston-Thomas Facility -- The impact on off-site sediment has been minimized by the remedial actions such as the removal of contaminated sediments from Clear Creek.
      Contaminants listed in the table on page 13 are a summary of those found at levels exceeding generic, media-specific comparison (screening) values (levels of concern) at the different sites (on and off site). Discussions of these contaminants appear in the individual site evaluations in the text. The bulleted comments above were based on information contained in the table on page 13. As noted, the table was intended as a summary to provide a list of contaminants found at levels exceeding comparison (screening) values (levels of concern) in various media at the different sites (on and off site). The table was not intended to give a before and after interim remedial action picture of the change in contaminant levels and locations. Indeed, after data are difficult to find.

    #39. Page 14 - Past completed exposure pathways. The report does not provide compelling evidence that these pathways were completed. Regardless, available epidemiologic data shows no indication that excessive exposure occurred.

      See responses to #21 and #24.

    #40. Page 15 - Review of health data. It is not clear why the cancer study for white females is specifically identified and it is stated that it showed a statistically significant increase in cancer of the ovaries, cervix, and uterus when it is specifically stated that there was not an environmental component to the cancers. Since there is not an environmental component to the cancers, the study is not relevant to this report. In addition, there is no consistent increase of any one particular cancer type (see Table 53 page 152) which would be expected if there was a relationship between an environmental exposure and the increase in cancer incidence.

      This analysis of health outcome data (HOD) follows current ATSDR guidance. When we evaluate cancer as a part of the HOD analysis, we analyze all anatomical sites, not just those for which there is strong scientific evidence. We use this conservative approach because most information about the carcinogenicity of chemicals is derived from animal models, which may not always accurately predict what will happen in humans. We presented the results pertaining to white females because these were the only data on anatomical sites that achieved statistical significance.

    #41. Page 16 - Chronic minimal risk level (MRL). The MRL is not defined and it appears that the concentrations for each of the media identified that were used to compare to the MRL were the maximum PCB concentrations in each matrix that were obtained prior to remedial measures. The data were not representative of past site conditions nor are the data representative of the present conditions at the sites. The MRL is presented in ATSDR's draft toxicological profile for PCBs. The MRL of 0.005 ug/kg/day (micrograms per kilograms per day) is calculated based on a LOAEL (lowest-observed-adverse-effect level) of 0.005 mg/kg/day (milligrams per kilogram per day) for immunological effects in monkeys as reported by Tryphonas et al. (1989). Specifically, monkeys exposed to low levels of PCBs exhibited somewhat lower levels of certain immunoglobulins relative to unexposed monkeys when exposed to sheep red blood cells. As pointed out in the toxicological profile, the adversity of the reported effect is questionable, i.e., the effect is characterized as a "less serious" effect. (In fact, the recent Health Panel convened by ATSDR for the Bloomington Project failed to reach consensus as to what amount of immunoglobulin level decrease could be considered clinically significant, much less adverse.) Deriving a risk-based criterion, even a screening criterion, based on this data is not technically defensible, especially when the purported LOAEL is based on a single study not supported by additional data. The MRL is based on a single endpoint and does not consider the weight of evidence provided by the complete toxicological data base. Moreover, the MRL is based solely on noncarcinogenic effects and thus does not reflect carcinogenicity, the effect which has previously been considered to be of primary importance with regard to risk-based criteria for PCBs.

      The definition of MRL and general information related to the derivation of the MRL are given on page 25 of Volume I of the PHA. ATSDR's MRLs are derived only for noncancer endpoints and are usually based on the results of well-conducted animal studies that demonstrate the most sensitive endpoint. MRLs are not environmental media specific; they are used to derive environmental specific screening guidelines called Environmental Media Evaluation Guides (EMEGs). ATSDR's Board of Scientific Counselors has endorsed the use of MRLs and EMEGs as generic, nonsite-specific screens that must be used in conjunction with other site-specific and chemical-specific information for toxicity assessment and determination of public health implications of chemicals. EMEGs are only one of several media-specific Cvs used by ATSDR health assessors to select substances for further evaluation in the PHA. Additional information on the derivation and use of ATSDR Cvs appears in the ATSDR PHAGM.

      According to ATSDR hierarchy for selection of contaminants for further discussion in the health assessment, the health assessor selects the lowest media-specific screening value regardless of whether it is based on cancer or noncancer endpoints. In the case of PCBs in soil, the ATSDR screening value was 0.01 ppm at the time Volume I of the PHA was being written. This value was lower than the 0.09 ppm soil CV based on the concern for cancer endpoints. The current noncancer CV for PCBs in soil is 0.04 ppm, based on a final revision of the MRL following external peer review and public comment and the publication of ATSDR's Toxicological Profile for Selected PCBs (April 1993). Assessors use the screen to select contaminants for further consideration and then evaluate the public health implications of contaminants. They consider both cancer and noncancer endpoints.

    #42. Page 17 - PCB Multi-Media Ingestion Exposure Dose and Cancer Risk Summary Table for All Consent Decree Sites. The basis for this table is not evident nor is there any indication how the "cancer risk" ratings were derived. The terminology suggests that at the very least a semi-quantitative analysis was performed, although the only details that were provided stated that PCB levels in site-specific media were compared to the MRL for PCBs and the doses were calculated based on daily exposure of children to evaluate the worst case scenario (page 147). Additional details regarding how the cancer risk determinations were made must be presented. This presentation of cancer risk severely misrepresents conditions at the sites, past and present. Specifically, (1) Bennett's Quarry surface soil - "very high increase." How was this quantified? Exposure to surface soils cannot currently occur because the site has been capped and fenced; (2) Lemon Lane subsurface soil - "high increase." How could exposure to subsurface soils have occurred even pre-interim remedial measures, to the extent that would result in a "high increase" in risk? Exposure cannot currently occur because the site has been capped and fenced; (3) Neal's Dump subsurface soil - "moderate increase." Exposure cannot currently occur because the site has been capped and fenced; (4) Neal's Dump on-site groundwater - "very high increase." There has been no known potable use of on-site groundwater and thus no exposure; therefore, there can be no risk. Off-site potable wells are clean; (5) Neal's Landfill on-site groundwater - "low increase." There is no current potable use of on-site groundwater. Since there is no exposure, there can be no risk; (6) Neal's Landfill off-site surface water and sediment - "low increase." Conard's Branch sediments have been remediated and the spring treatment facility removes PCBs before water discharges to Conard's Branch/Richland's Creek. Recent data indicate minimal concentrations; (7) Winston-Thomas sediment - "high increase." Clear Creek sediment has been removed and recent data indicate minimal concentrations. In addition, the development of the MRL in the draft ATSDR toxicological profile for PCBs (see comment 13) is based on a single endpoint and does not consider the weight of evidence provided by the complete toxicological data base. Moreover, the MRL is based solely on noncarcinogenic effects and thus does not reflect carcinogenicity, the effect which has previously been considered to be of primary importance with regard to risk-based criteria for PCBs.

      The cancer portion of the table is based on exceeding a 10-6 risk screening level based on the EPA oral cancer slope factor for PCBs and using standard exposure assumptions for soil ingestion and body weight as outlined in Appendix D-1 of the ATSDR PHAGM. The PHA addresses the potential for past, present, and future exposures, and we should view it in that context. With regard to issues related to the MRL, see response to #41.

    #43. Page 18 - Private Wells. Public water supplies are available in the vicinity of each of the sites except for Neal's Dump.More importantly, a hydrogeologic connection from the sites to private wells has not been demonstrated.

      While municipal water supplies are available in most locations, the current data do not prove that private wells are not being used. Likewise, the available data have not demonstrated that a hydrogeologic connection will never exist. Thus, we cannot eliminate this pathway and must consider it a potential exposure pathway. In lieu of hydrogeologic data indicating that a connection does not and will not exist, we recommend routine monitoring of private wells.

    #44. Page 18 - PCDDs/PCDFs at Bennett's Quarry. Westinghouse has not seen data to suggest that Bennett's Quarry contained PCDDs (polychlorinated dibenzo-p-dioxins)/PCDFs (polychlorinated dibenzo-p-furans). No such data are presented in the Bennett's Quarry groundwater Section (page 43).

      ATSDR agrees with the commenter that no data in the document justify the first sentence in the second paragraph on page 18. The ISDH has indicated that the first sentence of the second paragraph is an error and should be removed. Some dioxins/furans were detected at levels below health concern in surface soils (page 42). Removal of the sentence does not change the conclusions or recommendations of the report or affect ATSDR's conclusions or recommendations for Bennett's Quarry.

    #45. Page 18 - ISDH Recommendations 1 and 2. The bases for monitoring additional contaminants were not presented in the report.

      It is our understanding that all of these landfills are industrial landfills that have received a variety of domestic and industrial wastes--not just waste containing PCBs. By and large, sampling for other contaminants has not occurred. Therefore, where sampling for other contaminants has not occurred, monitoring for the levels of other site-related contaminants migrating into areas humans may occupy is necessary to determine any potential public health implications of the contaminants.

    #46. Page 19 - ISDH Recommendation 4. The Indiana Supreme Court upheld the 1 ppb (part per billion) limit specified in the Neal's Landfill Spring Treatment Facility National Pollutant Discharge Elimination System (NPDES) permit (Indiana Supreme Court, Case No. 36S01-9305-CV-560, IDEM and Westinghouse Electric Corp. v. Dale Conard, May 1993).

      The legal issues do not preclude ISDH from raising scientific questions regarding the situation.

    #47. Page 19 - ISDH Recommendation 7. There have been no demonstrations of any signs or symptoms of health effects resulting from environmental exposure to PCBs. There is an extensive occupational exposure data base, as well as data for less-exposed subpopulations and collectively, the only adverse health effects of PCBs that has been demonstrated on humans is chloracne in persons dermally exposed to commercial PCB mixtures. No adverse health effects associated with low-level exposure to PCB residues in the environment have been documented.

      These comments pertain to the ISDH recommendation that education programs be developed for health professionals. Since most primary care physicians and nurses in the area have not had training specific to occupational and environmental medicine and health, the ISDH felt it was important for these providers to have a better understanding of the actual health issues associated with exposure to PCBs. This recommendation directly addresses an important community health concern about the relevant knowledge of their health care providers, which is documented on page 163. Regarding signs and symptoms of exposure, see responses to #21 and #24.

    #48. Page 24 - Subsurface soil data. The rationale for evaluating subsurface soil data by using surface soil exposure assumptions is unsubstantiated. Subsurface soil concentrations are not likely to be less than surface soil concentrations in all cases. With the exception of Winston-Thomas Facility, the sites have been covered with clean soil or clay. In addition, surface soil contaminants are subject to leaching, weathering, volatilization, and aerobic biodegradation to a greater extent than subsurface soils. The use of worst case scenarios is unnecessary and misleading. The pathway analysis report should provide a realistic evaluation to support risk management decisions.

      The PHA indicates on page 24 that, when the sampling depth was not indicated on the data reviewed, we assumed that samples came from surface soils. This assumption, which was stated in this section, was the basis for some of the health conclusions. The health assessor would not otherwise have been able to use the data to determine whether contaminants were of possible health concern. ATSDR agrees that the current exposure potential from on-site areas where interim measures have been taken has been reduced or eliminated. However, off-site exposures may still be possible depending on what kind of interim steps have been taken.

    #49. Page 24 - Worst Case Scenarios. Use of worst case scenarios is unnecessary and misleading. The pathway analysis report should provide a realistic evaluation to support risk management decision and to identify further research needs.

      In lieu of complete exposure and site characterization data, the health assessor may, as a matter of public health conservatism, use a worst-case scenario.

    #50. Page 25 - Comparison Values. The report should cite references as well as derivation details for the comparison values CREG (cancer risk evaluation guide), EMEG, and RMEG (reference dose media evaluation guide).

    The environmental media evaluation guide (EMEG) values cited for evaluating soil and groundwater PCB data are inappropriate and should not be included in the pathways analysis report. In general, it is pointed out several places in the document, the pathways analysis report is not a risk assessment. In this respect, comparison of analytical data with risk-based EMEG values is outside the scope of the report.

    In addition, the ATSDR EMEG values for PCBs are suspect. These values are based on a minimal risk level (MRL) which is presented in ATSDR's draft toxicological profile for PCBs. The MRL of 0.005 ug/kg/day is calculated based on a LOAEL of 0.005 mg/kg/day for immunological effects in monkeys as reported by Tryphonas et al. (1989). Specifically, monkeys exposed to low levels of PCBs exhibited somewhat lower levels of certain immunoglobulins relative to unexposed monkeys when exposed to sheep red blood cells. As pointed out in the toxicological profile, the adversity of the reported effect is questionable, i.e. the effect is characterized as a "less serious" effect. [In fact, the recent health panel convened by ATSDR in Bloomington failed to reach consensus as to what amount of immunoglobulin level decrease could be considered clinically significant, much less adverse.] Deriving a risk-based criterion, even a screening criterion, based on this data is not technically defensible, especially when the purported LOAEL is based on a single study not supported by additional data. The MRL is based on a single endpoint and does not consider the weight of evidence provided by the complete toxicological data base. Moreover, the MRL is based solely on non-carcinogenic effects and thus does not reflect carcinogenicity, the effect which has previously been considered to be of primary importance with regard to risk-based criteria for PCBs.

    With regard to calculation of EMEG values based on the MRL, ATSDR should provide details regarding the exposure assumptions employed in the calculations and their relevance to the Bloomington sites. With particular regard to groundwater, the EMEG is tenfold less than the current drinking water standard (MCL [maximum contaminant level]) for PCBS, which is designed to protect public water supply systems. In general, the EMEG values are not well-documented, are not based on sound scientific data and appear to be derived using overly conservative exposure assumptions.

      See responses to #28 and #41.

    #51. Page 26 - Complete exposure pathways. ISDH does not adhere to the criteria for completed exposure pathways throughout the report. Many of the pathways characterized as completed lack one or more of the five required elements. Rather than characterize a pathway as completed if it can not be eliminated, ISDH should characterize pathways as complete only when there is evidence to support such a characterization.

    The report presents unsubstantiated exposure scenarios. Many of the exposure pathways and scenarios identified in the report are suspect. The report lists any pathway which it cannot definitively eliminate as a potential pathway. In doing so, the report does not follow its cited guidance which states that five key elements must be present for a pathway to exist, but many of the exposure pathways identified in the report lack one or more of the five required elements. In addition, many land uses and practices cited in the report are based on anecdotal and unsubstantiated information. For example, the report identifies consumption of wild game taken on-site as a completed exposure pathway for Lemon Lane Landfill in the present and future. However, post-IRM conditions (plastic cap and fencing) eliminate any potential for game to be exposed on-site. In addition, there is no information that people hunt wild game within city limits or that anyone has in fact hunted or consumed wild game from the site. As a second example, the report's estimate that 300 children are regularly exposed to Illinois Central Springs is a gross overestimate considering the small size of the area and the fact that it cannot support fishing or swimming.

      See response to #26.

    #52. Page 26 - The FWS is critical of the ISDH statement, page 26, which states "the sites in question have undergone remediation prior to 1987", since it is common knowledge that ambient air pollution exists at all sites, and as documented by FWS, PCBs continue to be flushed in significant quantities from the sites when it rains, undoubtedly with other contaminants.

      The FWS did not provide or cite ambient air data that indicate that a site-related air pollution problem exists. Pre- and post-ambient air sampling for Lemon Lane suggest that the interim remediations that have occurred have prohibited releases of site-related contaminants into the air (page 60, PHA Volume I). Furthermore, given the levels of contaminants detected in springs and streams associated with the various sites, it is very unlikely that releases into the air, if any, would be at levels that would have public health significance.

    III.C.1. Anderson Road Landfill Pathways Analysis

    #53. Page 29 - The waste at this site is emplaced without a liner on permeable stream and lake terrace deposits. Leachate has moved beyond the monitoring wells.

      The commenter is correct about the landfill not having a liner; this is typical for existing sanitary landfills. The PCB-contaminated waste, soils, and sediment were removed from this site in 1987. No data were submitted to support the allegation that leachate has moved beyond the monitoring wells. The groundwater monitoring from October 1989 through June 1993 shows no VOCs, semi-volatile organic compounds (SVOCs), or inorganic chemicals in the monitoring wells. There have been no detections of dioxin or furans in any leachate analysis from 1990 to 1993. (See last sentence on page 32 of Volume I.) Anderson Road Landfill does not pose a current public health hazard.

    #54. Page 32 - The results of borehole vapor monitoring indicates that many solvents are present in the waste material. The monitoring wells analyte list needs to include VOCs and SVOCs because the monitoring wells at the edge of the waste material are very close to the landfill margins. Off-site movement of contaminants, including residual PCBs is likely. These contaminants also need to be monitored in nearby residential wells.

      The groundwater monitoring from October 1989 through June 1993 has included analyses for VOCs and SVOCs; the data show no VOCs, SVOCs, or inorganic chemicals at levels of health concern.

    #55. Page 35 - The site is not adequately sealed from percolation by precipitation. Cover soil is not sealed with vegetation and rainfall causes erosion. Sediment run-off is severe. Surface streams are heavily sedimented and excavation of sediment traps is constantly required. Off-site movement of sediment is common. Contact with contaminated water, particularly for PCBs can lead to sediment carrying adsorbed substances off-site.

      The commenter is correct. The landfill is not sealed and vegetated. This situation is typical for an operating sanitary landfill. Until the landfill is closed, it is not possible to prevent rain from percolating into the landfill. While it is possible to control erosion and sediment runoff at an operating landfill to keep the sediment on site, it is not possible to eliminate erosion. However, the PCB-contaminated wastes, soil, and sediment were removed from the site in 1987. So the sediment being carried off site and the leachate caused by rain percolating through the landfill should not contain any PCBs. The sediment and leachate would be expected to be the same as from any other operating sanitary landfill. The groundwater monitoring from October 1989 through June 1993 shows no VOCs, SVOCs, or inorganic chemicals. Dioxin and furans have not been detected in any analysis of leachate taken from 1990 to 1993. (See page 32 of PHA Volume I.) Therefore, we do not believe that the Anderson Road Landfill poses a current public health hazard.

    #56. Page 35 - Table 4. Completed Exposure Pathways for Anderson Road Landfill. Bases for number of exposed persons for the on-site ambient air and on-site surface soil pathways are not identified.

      As discussed in the Pathway Analysis Section (pages 26 and 27), "It is impossible to estimate the actual number of individuals who may have trespassed on these sites, particularly where the capacitors were deposited." The estimate of exposed persons is based on information provided by approximately 50 individuals regarding frequency of scavenging activities and the locations where the activities occurred. Most scavengers performed activities at most, if not all, of the six consent decree sites, resulting in multiple exposures.

    #57. Page 37 - Table--Potential Exposure Pathways for Anderson Road Landfill. Basis for number of exposed persons for the on-site surface water is not identified.

      Please refer to the reference discussed on page 27 of the PHA under Pathway Analysis. See response to #55.

    III.C.2. Bennett Stone Quarry Pathways Analysis

    #58. Page 38 - Site History. The reference identifying the past use of Stout's Creek and quarries near Bennett Stone Quarry for mudbaths and swimming, respectively, was not presented.

      Please refer to the reference discussed on page 27 of the PHA under Pathway Analysis. See response to #56.

    #59. Page 40. Areas with trees at this and other sites act as windows through the installed covers. Precipitation has access through these gaps, resulting in mobilization of contaminants. Stout's Creek needs periodic monitoring of water and stream sediments. The problem is most severe during higher precipitation events because of the flushing action and sediment loads from karst as primary carriers of sorbed contaminants.

      ATSDR agrees that there is a need for periodic monitoring until permanent remediations are performed. In a January 1994 letter, the FWS indicated to ISDH that fish collected in 1992 from Stout's Creek and from Bean Blossom Creek downstream of its confluence with Stout's Creek contained levels of PCBs higher than 3 ppm. This suggests that water, sediments, fish, and other wildlife may have been recontaminated since the 1988 sampling. However, the question of whether humans use fish and wild game from those portions of Stout's and Bean Blossom creeks as food sources is critical to our evaluation of human exposure. What kinds of edible fish and game are in those areas remains unclear to ATSDR. However, based on observations during site visits, it appears to ATSDR that those areas are unlikely to serve as sources of fish and game for regular (or even occasional) human consumption. Therefore, there is no public health hazard likely for these areas. On the other hand, data may be sufficient to determine whether ecological impacts may exist. Appropriate agencies will make that determination.

    #60. Page 42 - Table 6--On-Site Multi-Media Sample Results from Bennett Stone Quarry, May 1983. The PCB concentrations presented for each of the media should be identified as maximum sample concentrations ever detected. These values are not representative of the site even prior to the remedial measures. Specifically, the soil PCB concentrations represent stained soils and in some cases were collected adjacent to leaking capacitors.

      As Table 6 (page 42) shows, the PCB concentrations presented for each of the media are identified in the third column heading as "Maximum PCB Concentration (ppm)." Although ATSDR does agree that maximum concentrations are not always representative of exposure potential at a site, maximum concentrations are used in the PHA process to screen, identify, and select contaminants of concern for further evaluation.

    #61. Page 42. The detection level of 5 ppb for sediments where the level of concern is .01 ppb is an example of poor quality assurance. A properly managed RI/FS (remedial investigation/feasibility study) would have data quality objectives for the analytical requirements. One of them is the required detection level needed to assess the health risk, to determine the level of contamination, or to evaluate remediation alternatives. This detection level question is persistent throughout the data base.

      Table 6 (page 42) indicates that the detection limit is about 5 parts per million, not parts per billion. The environmental data reported in the table were from 1983, prior to interim actions taken at the site. Cvs are not health endpoints (i.e., thresholds for effects). Cvs are, as a matter of policy, conservative values to be used as screens that require health assessors to look more closely at exposure potential and the toxicologic/epidemiologic databases. Exceeding a CV does not necessarily indicate increased likelihood of a health hazard. Determination of a health hazard involves evaluation of all factors and the application of professional judgement. See responses to #28 and #41.

    #62. Page 43. Another RI/FS issue is the lack of field sampling plans. The location of boreholes and the depth of sampling is critical to the adequate assessment of a site. Soil sampling at this site did not extend below 48 inches and most to less than 12 inches. Even as sparse as this was, some soils contain >5% PCBs and water wells had a separated PCB oil phase. An adequate site characterization is absolutely necessary for this site.

      The commenter is correct that characterization of the site for final remediation purposes requires adequate sampling. However, for assessing human health impact, soil sampling below 48 inches at this site is not likely to matter. Direct contact with contamination by trespassers or the general public would not be expected at depths below 3 inches. Furthermore, the on-site wells are not being used for drinking water. Therefore, direct human exposures are not likely under current conditions. Present monitoring of off-site areas should provide adequate indications of the potential for human exposure.

    #63. Page 45 - Fish concentrations. The fish sampling results cited were from 1984. This was prior to remedial measures (clay cap and stream cleaning) and is not representative of present conditions for the streams. The FDA (Food and Drug Administration) Guideline of 2 ppm is for edible fish tissue. The report does not distinguish between whole body fish and edible tissue.

      Table 8 (page 45) indicates that the samples were collected in 1984. According to ISDH, all data are for whole fish. The definition of edible fish versus whole fish varies, depending on cultural practices of persons catching and eating the fish. There are anecdotal reports of Asian students fishing in and around these areas. In some Asian cultures, the whole fish is cooked to make a fish stock or soup. Indiana University's registrar's office indicates that there are approximately 1,600 Asian students in the Bloomington area. As noted previously, there is a need for information regarding dietary use, if any, of fish caught in these waters.

    #64. Page 45 - Table 8--Off-Site Fish Sample Results, Bennett Stone Quarry, March 1984. As stated previously, the fish sampling results cited were from 1984 and analytical results that are not representative of current conditions should not be compared to a comparison value to demonstrate a potential health risk.

      See response to #63. We did not use the 1984 fish sampling data for PCB contamination to determine possible current exposures. Page 47 reports that the "current concentrations of PCBs in stream sediments are unknown." Except for the groundwater pathway, all exposure pathways (potentially completed and completed) are listed as past exposure pathways (tables 9 and 10). Levels of PCBs in fish in creeks affected by Bennett's may be increasing and therefore may represent a potential future pathway if humans eat fish from those waters. (See #59.)

    #65. Page 45. The fish sampling clearly indicates a leachate escape and stream contamination at least to Bean Blossom Creek. Although sediments have been removed, the leakage to Stout's Creek needs to be monitored on a regular basis

      Data for these conclusions come from 1984. However, Stout's Creek may still be receiving contamination. (See #59.)

    #66. Page 47. The presence of separated phase of PCB oil in MW-5 adjacent to Stout's Creek indicates more than simple dissolved levels of PCB as a threat from this site. Because the transformer oil is fluid, it is likely that PCB transformer oil will seep off-site. Considering ground or surface water contact as only a past exposure pathway ignores the continued presence of mobile contamination.

      The data suggest that it is likely that the contaminated groundwater has moved off site and will continue to move off site. (See response to #59.) However, if no one is currently being exposed to the contaminated groundwater or surface water, a completed exposure pathway does not exist. Municipal water is available to nearby residents, but some questions have been raised regarding some residents still using their private wells. (See response to #8.) Samples collected from residential wells in 1983, 1986, and August 1988 were analyzed for PCBs. All samples contained less than 1 ppb, a level below health concern. Because current information about well use was not available, ISDH designated the off-site groundwater pathway as a potential pathway both currently and in the future. Page 169 contains a recommendation for a survey of residential wells near Bennett Stone Quarry. The recommendation suggests that, if any private wells are still in use, they be analyzed for "hazardous substances"--the full Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) screening list of contaminants--not just for PCBs.

    #67. Page 48 - Table 9--Completed Exposure Pathways for Bennett Stone Quarry. Bases for number of exposed persons for the on-site and off-site ambient air, on-site surface soil, off-site surface water, and off-surface sediment are not identified.

      See response to comment #56.

    #68. Page 49. Bennett Stone Quarry Off-site Groundwater Hydrogeologic studies show that the groundwater flow is to the west-northwest to Stout's Creek; therefore, the groundwater does not impact private wells.

      Based on information that was available, ATSDR agrees that the shallow aquifer does predominantly discharge to Stout's Creek, as stated on page 49. However, as noted in the responses to #26 and #43, where information is not sufficient to eliminate a pathway, that pathway is considered potential. Page 49 of the PHA indicates that knowledge gaps remain concerning aquifers beneath the site and the number and locations of residential wells in the area. (See #66.) Thus, data are not sufficient to eliminate concerns regarding connections from deeper aquifers, if any, to private wells west and northwest of the site. Available monitoring data for private wells in the vicinity suggest that, at least up to 1988, the site had no impact on the wells.

    #69. Page 50 - Table 10. Potential Exposure Pathways for Bennett Stone Quarry. Bases for number of exposed persons for the on-site surface water and off-site groundwater are not identified.

      See response to comment #56.


    Next Section       Table of Contents

     
  •  
    USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
    Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
    Contact CDC: 800-232-4636 / TTY: 888-232-6348

    A-Z Index

    1. A
    2. B
    3. C
    4. D
    5. E
    6. F
    7. G
    8. H
    9. I
    10. J
    11. K
    12. L
    13. M
    14. N
    15. O
    16. P
    17. Q
    18. R
    19. S
    20. T
    21. U
    22. V
    23. W
    24. X
    25. Y
    26. Z
    27. #