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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 - CONTINUED

III.C.3. Lemon Lane Landfill Pathways Analysis

#70. Page 52 - The 10/5/94 presentation by Westinghouse concluded that 07% of the injected dye recovered in the 1989-1990 dye trace studies was at the Quarry Spring-Illinois Central Spring system. A number of questions exist:

    1) What were the relations of dye injection points and the overall flow system? The injection points may be attached to sub-areas of the karst drainage.

    2) What type and quantity of dye was injected in each well and what portion of each was detected at each spring? Losses are significant and to assume that the error does not obscure a significant component of groundwater flow is to invite a leaky enclosure.

    3) The depiction of low flow conditions alone is not adequate. High rainfall conditions lead to significant flow at many other points. In fact, it is under high-flow conditions that PCB-laden sediment is most mobile and would be transported off-site.

    4) Detmer Spring and the level and identity of contaminants appears to be lost in this view of Lemon Lane hydrology. If it is no longer part of the Lemon Lane system, what system (and source) is responsible? and how will it be addressed?

A more recent dye tracer study (Indiana University) of Lemon Lane is finding more dye "outlets" from the landfill than were indicated in the earlier study.

    While the hydrogeology of Lemon Lane has not been completely characterized, sampling for PCBs, a number of common VOCs, and selected metals was conducted in 1991 in the springs and sediments associated with Lemon Lane, including the Detmer Springs. A discussion of this sampling appears in Volume I of this PHA, pages 65-68, and a summary is in tables 18 and 19 (pages 66 and 67, respectively). The highest PCB levels were associated with sediments in the Illinois Springs (8-58 ppm); Detmer Springs had 0.7 ppm. Continued monitoring of these areas and new areas as indicated by dye studies is recommended as a means of assessing impacts on humans and the ecology. More thorough characterization may be required before selection of an appropriate remedial option but, given feasible human exposure scenarios, that additional characterization may not significantly affect the assessment of public health.

#71. Page 53 - Groundwater flow. From data gathered during low flow conditions, groundwater is interpreted to flow southeast and eventually drain at Illinois Central Spring and the Quarry Spring. During high flow conditions, the primary flow network from the landfill is Illinois Central and Quarry Springs. A minor amount of groundwater from beneath the landfill is believed to flow northwest and discharge at Slaughterhouse, PH Road, PH culvert, and to other headwaters of Clear Creek.

    The question appears to be whether under high flow conditions the primary groundwater flow is to the east as suggested on page 53 or to the southeast toward Illinois Central Spring and Quarry Springs as suggested by the commenter. From ATSDR's perspective, as long as human exposure in these areas, i.e., east or southeast, is limited or eliminated completely, significant exposures and adverse health effects are not likely to occur.

#72. Page 54--Aquifer flows. The shallow aquifer is located approximately 80 to 90 feet below the land surface and the deep aquifer is 100 to 120 feet below the land surface. During low-flow periods and high-flow periods, the deep aquifer flows to the southeast.

    The commenter is apparently pointing out differences in interpretation of the data concerning depths of the aquifers. Page 54 states that "the shallow aquifer is located approximately 11 to 22 feet below the surface with the deep aquifer occurring at 38 to 50 feet below the soil surface." Resolution of this issue could be important for remedial selection but is not likely to affect impact on human health. See response to #70 with regard to data required for public health evaluation versus data required for remedial option selection.

#73. Page 55--Ambient air PCB concentrations. The ambient air sampling results presented are from June and July 1983, prior to the placement of a synthetic cap over the entire site. Therefore, these results are not representative of present conditions at the site and should not be used to determine if the PCB concentration in the ambient air at the site are "considered to be of concern". In fact, testing performed by EPA in July of 1989, after the completion of the remedial measures, to show "worst case" concentrations resulted in PCB levels of less than 0.04 ug/m3 (micrograms per cubic meter) (USEPA Neighborhood Update, Air Sampling Data, Bloomington, Indiana, September 12, 1989).

    ATSDR concurs with the commenter's suggestion that we avoid using past data to determine current exposures. Past data are used to highlight past exposures. Thus, levels of PCBs detected in the air before interim remedial actions are considered to be of concern for past exposures. After the interim measures were completed, it is logical that air and dust emissions from the site would be reduced dramatically. Although not mentioned in the ambient air data discussions on pages 54 and 60, the pathway analyses discussion (page 68) indicates that "the latest air monitoring of this site was non-detect." It also states that "ambient air on and around the Lemon Lane Landfill is considered to be a past completed exposure pathway through inhalation."

#74. Page 55 - Table 11--On-Site Boring PCB Sample Results for Lemon Lane Landfill, March 1984. The on-site soil is inaccessible because of remedial measures such as fencing and placement of a synthetic cap. 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 #73 regarding the use of environmental data collected in the past. Because of interim actions, there appears to be no current completed pathway to on-site soils.

#75. Page 55 - The three borings and sparse sampling at this site are inadequate to indicate the extent of contamination.

    The commenter is correct. The full extent of contamination related to Lemon Lane Landfill has not been determined. However, there has been a substantial number of samples taken on and around the site. A summary of the available data appears in Volume I, pages 54-68, of this PHA. A number of these analyses included information on VOCs, SVOCs, pesticides, and metals, and several samples were also analyzed for dioxins and furans. The following recommendations appear on pages 169 and 170: (1) that if private wells near this site are still in use, they be sampled and analyzed for contaminants other than just PCBs; (2) that additional information be collected on PCB contamination in the wooded areas; and (3) that the springs and streams associated with this site be analyzed for dioxins and furans. The purpose of the latter two recommendations is to fill data gaps relevant to site characterization. The purpose of the first recommendation is to assure that public health is not being compromised.

#76. Page 56 - Table 12--On-Site Surface Soil/Boring Sample Results for Dioxins and Furans, October 1984. As stated previously, the on-site soil is inaccessible because of remedial measures such as fencing and placement of a synthetic cap. 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 comment #73.

#77. Page 57 - Table 13--On-site Subsurface Soil Total PCB Sample Results for Lemon Lane Landfill, June 1981. The range of concentrations of PCBs in the subsoil represent maximum concentrations in the samples taken from each boring. The minimum concentration of PCBs found was below detectable limits, not 1700 ppm for ISDH or 28,118 for the City of Bloomington. Again, analytical results that are not representative of current conditions should not be compared to a comparison value to demonstrate a potential health risk.

    According to the narrative on page 57, all subsurface soil samples collected in 1981 contained measurable levels of PCBs. However, even if the commenter is correct that some of the samples were non-detects, ISDH did not include these subsurface soils as part of completed or potential exposure pathways.

#78. Page 58 - Table 14--EPA On-Site Subsurface Soil PCB Sample Results for Lemon Lane Landfill, June/July, 1981. The on-site subsurface soil is inaccessible because of remedial measures such as fencing and placement of a synthetic cap. 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 comment #73.

#79. Page 59 - Table 15--On-Site Sediment Results for Lemon Lane Landfill, March 1987. The sediment samples collected by EPA were from springs near the site not on-site at Lemon Lane Landfill. Analytical results that are not representative of current conditions should not be compared to a comparison value to demonstrate a potential health risk. Analytical data for springs sediment are available from a November 1991 sampling event.

    The comment is noted. The ISDH has indicated that the data are likely from off-site locations. This correction does not change the conclusions or recommendations. Discussion of the November 1991 sampling data appears on pages 65 through 69. Past data are not used to assess current exposures. (See response to #73.)

#80. Page 59 - Table 15 does not show any of the solvents detected in the 1987 samplings, but does show a number of PNAs (polynuclear aromatics) which are semi-volatile hydrocarbons.

    Substances listed in Tables 15 and 17 are those detected at levels that exceeded appropriate CVs or for which no CVs have been developed. According to ATSDR guidelines, substances detected at levels exceeding CVs are considered substances of concern and require further evaluation of their associated exposure pathways and public health implications. Substances detected but at levels below CVs are generally not included in further discussions in PHAs.

#81. Page 60 - Ambient air monitoring. The ambient air monitoring data presented for June through September, 1987, were obtained during the remedial measures when the landfill was being cleared of trees and vegetation and being regraded. These measures included the removal of exposed capacitors, stabilizing the south slope, covering the landfill with geotextile and placing of clean fill, covering the site with a synthetic cap, and placement of the vent gas treatment system. These remedial measures have effectively eliminated the ambient air at the site as a potential exposure pathway as evidenced by the July 1989 EPA ambient air sampling at Lemon Lane (USEPA Neighborhood Update, Air Sampling Data, Bloomington, Indiana, September 12, 1989).

    Volume I of the PHA reviewed past and present data to determine the likelihood of past, present, and future human exposures to contaminants. In this case, past data were used to identify potential off-site ambient air exposure points and then to evaluate the possibility of a past completed pathway. Although the July 1989 EPA ambient air sampling data may have shown an elimination of the potential exposure point, the pathway is still regarded as a past completed pathway. With regard to present and future exposure pathways, the fact that contamination remains on site suggests that some airborne exposure may still be possible, although in ATSDR's opinion very unlikely. Air monitoring data obtained following remediation did not detect site-related PCB contamination. (See response to #73.)

#82. Page 61 - Off-site soils at Lemon-Lane Landfill with dioxins above the level of health concern are not cited as exposure pathways in Table 21.

    Based on experience at determining hazards associated with dioxins and furans at sites throughout the U.S., ATSDR has adopted a policy that states "that at sites where total dioxin equivalency levels in residential soil exceed 1 ppb (which is equivalent to 0.001 ppm), the contaminant and environmental medium should be selected for further consideration." In general, ATSDR believes that total residential area dioxin equivalent levels that are below 1 ppb (0.001 ppm) do not pose any significant health risk. At the Lemon Lane location, the total equivalents level in the off-site soils was 0.000006 ppm, a level approximately 1,000 times less than ATSDR's policy value. Thus, a decision was made to eliminate dioxins/furans as a component of an off-site soil pathway at Lemon Lane even though they exceeded CVs based on theoretical cancer risks. See responses to #28 and #41 for discussions on what CVs and MRLs represent.

#83. Page 62 - Table 16--Off-Site Groundwater Monitoring Well Sample Results for Lemon Lane Landfill. October 1982 and June 1983. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk.

    See response to comment #73.

#84. Page 64 - Table 17--Off-Site Spring Surface Water Sample Results for Lemon Lane Landfill, July/December 1982. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Analytical data for springs are available from a November 1991 sampling event.

In addition, details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. The EMEG value is tenfold less than the current drinking water MCL 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 over-conservative exposure assumptions.

    See responses to comments #73 and #41, respectively.

#85. Page 64 - VOCs (7) and inorganics (8) were detected in 7/82 springs sampling; only 3 VOCs and 1 SVOCs are cited in Table 17. Then in the 12/82 sampling 13 organics, 11 inorganics, and PCBs were detected, again discrepancies.

    See response to comment #80.

#86. Page 65 - The sampling locations and detections for the EPA 7/91 sampling are needed to show the most current presence of contamination.

    Figure 13 (page A-13) of the PHA contains the sample locations for June 1991 sediment samples. Figures 12 and 14, respectively (pages A-12 and A-14) contain sample locations for November 1991 surface water and sediment sampling. Data summaries from both sampling times are displayed and discussed on pages 65 through 68 of the PHA. The PHA does not contain sampling information from 7/91.

#87. Page 66 - Both water and sediment data should be presented for the 6 and 11/91 samplings.

    These data are displayed in Tables 18 and 19 or are included in the text on pages 65, 67, and 68.

#88. Page 66 - Table 18--Off-Site Spring & Streams Surface Water PCB Sample Results from Lemon Lane Landfill, November 1991. Details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. The EMEG value is tenfold less than the current drinking water MCL 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 response to #28 and #41.

#89. Page 67 - Background Sediment PCB Concentration. Analytical results of the background sediment sample taken from a spring at Oard Spring at Oard Road Bridge should be presented.

    The narrative on page 67 indicates that the sample was below detection levels. Since detection levels may vary from study to study, ATSDR agrees that including background levels might have provided a useful perspective. However, we select contaminants of concern in pathways for further discussion because they exceed CVs as described in #28 and #41, not because they exceed background levels.

#90. Page 68--The QA/QC (quality assurance/quality control) elimination of data is not adequately justified. The 7/82 spring samples were dismissed as unusable. Why? 3/87 sediment data was dismissed because of a sampling contamination? The remainder of the data is usable at a minimum as indicative or semiquantitative.

    Additional details about the reasons for not using the data would have helped make the story more complete. However, it has been ATSDR's experience that, more often than not, the data didn't meet QA/QC criteria. Based on other data available (from 1987 and 1991), it is doubtful that the 1982 data would have much of an impact on the conclusions and recommendations. Feasible human exposure potential is still the critical factor in assessing hazards.

#91. Page 68 - Dioxins and furans are potentially present in springs from past site activity. The landfill springs should be checked for these as part of the routine sampling. ATSDR should be very specific about the data gaps that inhibit an adequate health assessment.

    Given the levels and congeners that were detected in soil (see Table 12, page 56) and the limited potential for human exposure at the springs, ATSDR does not believe that, from a human health perspective, there is a justifiable rationale for sampling for dioxins and furans in these springs unless some other source of contamination is suspected. See #82 for discussion of dioxins/furans at Lemon Lane.

#92. Page 69 - Game Consumption. ISDH does not follow this guidance later in the report when identifying completed exposure pathways. Many of the pathways characterized as completed lack one or more of the five required elements. Rather than characterize pathways as completed if it cannot be eliminated, ISDH should characterize pathways as completed only when there is evidence to support such a characterization.

    See response to #26

#93. Page 70 - Table 20--Completed Exposure Pathways for Lemon Lane Landfill. Regarding on- and off-site wild game, the report presents no compelling evidence that this exposure pathway actually occurred. The dose study that is referenced on page 69 does not necessarily indicate that wild game were exposed or that they were taken by hunters in the vicinity of the site. Bases for number of exposed persons for each of the pathways are not identified.

    On page 69, the PHA indicates that the ISDH staff talked with people who consume wild game that "roamed the Lemon Lane Landfill and/or its associated springs and depressions...." Page 27 of the Pathways Analysis Section contains a discussion of the basis for determining the persons exposed. See also response to #56.

#94. Page 71 - The complexity of karst and its effect on groundwater flow are clear in the difference between low and high conditions during dye trace studies at this site. The presence of two water bearing zones and numerous springs make the current Westinghouse assertion that about 97% of the water from Lemon Lane LF exits the site through the Illinois and Quarry Springs streams unlikely to be true. They are also asserting that the contamination from Detmer Spring (which this report does not adequately treat) as not derived from Lemon Lane.

    See response to #70. Note also that Detmer Springs is listed in Table 19 and shown in figures A-11 and A-13.

#95. Page 71 - Ambient Air. Ambient air should not be considered a potential exposure pathway for Lemon Lane. Available monitoring data indicate non-detectable PCB levels at the site. Interim remedial measures eliminate the possibility of significant volatilization or dust generation. The PCB concentrations present in spring waters are too low to cause detectable concentrations in nearby air. The statement about "compromised" air quality in the Illinois Central Springs area following major rainfall events should be clarified. Since no data are cited, this statement cannot refer to PCBs. More likely, it refers to odors, such as those associated with domestic sewage, which is not attributable to Lemon Lane landfill. This misleading statement should be clarified. Finally, the reference to air quality at Conard's Branch is irrelevant to the Lemon Lane site and should be deleted.

    On- and off-site ambient air is listed on page 70 as a completed past pathway. It is a past pathway because of the history of on-site burning of capacitors and PCB-contaminated materials and because of work practices in effect during the landfill's operation. Off-site ambient air is listed on page 72 as a potential past, present, and future exposure pathway. Page 68 reports that the latest air monitoring data of this site was non-detect, making the current and future exposure to contaminated air a potential pathway, not a completed one. Also see response to #29. The commenter is correct regarding Conard's Branch not being associated with Lemon Lane.

#96. Page 71 - Exposure at Illinois Central. The characterization of extensive exposure of children to PCBs in the Illinois Central Springs drainage is misleading. It is unlikely that children play in these areas "on a regular basis" as the report suggests. The estimate of the exposed population (on p. 72) as 300 individuals is a gross overestimate given the small size and remote location of the area where detectable PCB concentrations were found. The small size of the stream in this area is insufficient for swimming or any other recreational activity.

    The PHA (page 71) states that ISDH has been told by community members that "children play in and around these springs and streams on a regular basis." The estimate of the exposed population reflects past, present, and future exposures. See also response to #56.

#97. Page 71 - Table 21--Potential Exposure Pathways for Lemon Lane Landfill. Bases for number of exposed persons for each of the pathways are not identified.

    The basis for estimates of persons exposed appears on page 27 of the Pathways Analysis Section.

III.C.4. Neal's Dump Pathways Analysis

#98. Page 73--Interim remedial measures. A soil cover was placed over Neal's Dump not a clay cap.

    The commenter is correct. This correction would not affect any final conclusions or recommendations for this site.

#99. Page 74 - The White River is the discharge recipient for all drainage from the site. It is a drinking water and food resource for many people downstream. Levels of 275 ppm in off-site sediments and 240 ppb in the shallow aquifer (p. 82) and no clean-up action certainly indicate an ongoing contamination problem.

    The surface contamination was removed from this site, and a soil cap was placed over the dump area. Sampling of off-site sediment in the north-northwest ravine stream in 1983 did not detect PCBs. The sampled areas were in the same location that had levels as 275 ppm in 1976 before the removal action; therefore, contaminated runoff to the White River is not likely to be occurring. Furthermore, during a 1993 site visit, the ditch area was overgrown with vegetation and did not seem to offer opportunities for frequent, direct public contact. Results of groundwater monitoring suggest that levels of PCBs reaching the White River, if any, would be inconsequential from a public health perspective.

#100. Page 76 - Table 22--On-Site PCB Soil Sample Results for Neal's Dump. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. The EMEG values are not well-documented, are not based on sound scientific data, and appear to be derived using overly conservative exposure assumptions. In addition, the EMEG comparison value for PCBs in soil in this table is given as 0.001 ppm while in previous tables the value was given as 0.01 ppm.

    The 0.001 is incorrect. For discussions on the use of past data for assessing current exposures, for EMEGs, and for MRLs, see responses to #73, #41, and #28, respectively.

#101. Page 78 - Table 23--On-Site Groundwater Monitoring Well PCB Sample Results for Neal's Dump, May 1987 - May 1993. Details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. The EMEG value is tenfold less than the current drinking water MCL 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 response to #28.

#102. Page 79--PCB concentrations in residential wells. Follow-up samples from residential wells near Neal's Dump confirmed that there was no PCB contamination.

    PCBs were detected in monitoring wells in 1991. Available hydrogeologic data are not sufficient to confirm that a hydrogeologic connection between residential aquifers and the aquifers identified in monitoring wells will never exist. Thus, as stated in Recommendation 1 for Neal's Dump (see page 170), it is very important to continue routine periodic sampling of the private wells around this site to ensure that humans are not exposed to PCBs or other hazardous substances that may be in the dump.

#103. Page 80 - QA/QC rejection of data for methylene chloride or phthalates as laboratory artifacts must be justified depending on their detection and concentration in the QC samples. These substances are also major contaminants from landfills.

    These are common laboratory contaminants often found in field and other laboratory blanks. Evaluation of the data led the health assessors to eliminate the data. However, even assuming the contamination was site related, human exposure to the levels reported would not be considered to be of public health significance.

#104. Page 80 - Neal's Dump cap. A soil cover was placed over Neal's Dump not a clay cap.

    See response to #98.

#105. Page 82 - Table 24--Completed Exposure Pathways for Neal's Dump. Basis for number of exposed persons for the on-site surface soil pathway is not identified.

    See response to #56.

#106. Page 82--Off-site groundwater. The 240 ppb concentration of PCBs was detected in the deepest well in the shallow aquifer. The well is located directly down gradient of the site in a stratigraphic trough where it was expected that PCBs would concentrate. The highest concentration of PCBs detected in the other shallow wells is 5.4 ppb in May 1987. Residential wells are expected to be protected from potential contamination from the site by a clay layer that appears to geologically and hydrologically isolate the wells from Neal's Dump. The two residential wells closest to the site are monitored annually and have never had detectable levels of PCBs in the well water.

    See response to #102.

#107. Page 83 - Table 25--Potential Exposure Pathways for Neal's Dump. Available data show either minimal (< 1 ppm) or non-detectable PCB levels in sediments. Exposure to off-site surface water and sediment in not a viable pathway since these media are uncontaminated. Bases for number of exposed persons for the pathways are not identified.

    See response to #99. The numbers of exposed persons for these potential pathways in Table 25 are based on the health assessor's estimates of either the number of persons residing within a 3-mile radius who use private wells or the number of hikers who traversed the ditches in the past.

III.C.5. Neal's Landfill Pathways Analysis

#108. Page 84 - The soil caps at this site and others (Bennett's and Neal's Dump) have numerous gaps where trees grow. These act as conduits for precipitation into the landfill debris to mobilize contaminants. Also, the discharge limit for National Pollutant Discharge Elimination System (NPDES) is set at 1 ppb which is above the health limit, but not all water has to meet this criteria. Most effluent water bypasses the treatment system particularly in high flow conditions when PCB-laden sediment is mobilized.

    The commenter is correct. The soil caps do not prevent precipitation from percolating through the landfills and leaching hazardous constituents out of the wastes that are present in the three landfills mentioned. See response to #59.

#109. Page 85--Fish and Wildlife Service. The statement by the Fish and Wildlife Service report that human health is not adequately protected by the existing permit limit is incorrect. Data from the Fish and Wildlife Service (April 1991) shows PCB concentrations less than the FDA limit of 2 ppm. The 2 ppm FDA guideline is for edible fish tissue. A distinction between whole-body fish data and edible fish tissue should be made. Whole-body fish samples include tissue such as fat and organs where PCBs concentrate, but which are typically not eaten.

    ATSDR agrees that, where possible, reports should indicate whether the analysis was conducted on edible fish tissue or digested whole fish. According to ISDH, all data are for whole fish. Depending on the kinds of fish and on local population customs, whole fish may be considered edible fish tissue. Perhaps most critical to assessment of effects on human populations are data on whether the portions of waterways affected by the site will support the kind of fish that humans are likely to consume. See response to #59.

#110. Page 90 - Table 26--On-Site Surface Soil Sample Results for Dioxin and Furan Congeners, Neal's Landfill, September 8, 1983. The on-site surface soil is inaccessible because of remedial measures such as fencing and placement of a clay cap. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. In addition, details should be provided regarding the exposure assumptions employed in the calculation of the comparison values and their relevance to the Bloomington sites.

The TEF (toxicity equivalency factor) concentration should not be reported for each congener group. TEFs are designed to give a single 2,3,7,8-TCDD (tetrachlorodibenzo-p-dioxin) equivalent for all PCDD congeners collectively. In addition, more detail on the TEFs that were employed should be provided, as well as referenced.

    The TEF approach is outlined in EPA's Interim Procedures for Estimating Risks Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-dioxins and -Dibenzofurans (CDDs and CDFs) and 1989 Update (EPA/625/3-89/016). To be conservative and because of public interest in dioxins, the health assessors assumed that dioxins/furans detected were 2,3,7,8-congeners, and they therefore applied TEFs associated with such congeners. Even using the assumption that the detected dioxins/furans were 2,3,7,8-congeners, the total TEF concentration was less than 1 ppb, ATSDR's policy level for residential soils (see #82). See responses to #28 and #41 for exposure assumptions and #73 for information about use of past data.

#111. Page 91 - Table 27--On-Site Soil Boring Sample Results for Dioxin, Neal's Landfill, October 30 1984. The on-site surface and subsurface soil is inaccessible because of remedial measures such as fencing and placement of a clay cap. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. In addition, details should be provided regarding the exposure assumptions employed in the calculation of the comparison values and their relevance to the Bloomington sites.

The TEF concentration should not be reported for each congener group. TEFs are designed to give a single 2,3,7,8-TCDD equivalent for all PCDD congeners collectively.

In addition, more detail on the TEFs that were employed should be provided, as well as referenced.

    See response to #110.

#112. Page 94 - Table 29--On-Site Groundwater PCB Sample Results for Neal's Landfill, l982-83. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. In addition, details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. The EMEG value is tenfold less than the current drinking water MCL 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 #73 and #41.

#113. Page 95 - Table 30--On-Site Groundwater PCB Sample Results for Neal's Landfill, 1982-83. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk.

    See response to comment #73.

#114. Page 96 - Table 31--On-Site Surface Water PCB Sample Results for Neal's Landfill, 1982-83. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. In addition, details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. The EMEG value is tenfold less than the current drinking water MCL 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 #73 and #41.

#115. Page 98 - Table 32--Off-Site Stream Surface Water Inorganic Sample Results for Neal's Landfill, November 3, 1980. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. In addition, details should be provided regarding the exposure assumptions employed in the calculation of the comparison values and their relevance to the Bloomington sites.

    See responses to #73 and #41.

#116. Page 99 - Table 33--Off-Site Spring Surface Water Organic and Inorganic Sample Results, Neal's Landfill, July 28 & 29, 1982. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk.

    See responses to comments #73 and #41.

#117. Page 100 - Table 34--Off-Site Sediment Sample Results for Richland Creek & Conard's Branch, October 26, 1992. Details should be provided regarding the exposure assumptions employed in the calculation of the comparison values and their relevance to the Bloomington sites.  

    See responses to #73 and #41.

#118. Page 101 - Table 35--Off-Site Fish PCB Sample Results, Neal's Landfill, January 20, 1982. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Fish sampling was conducted by the US Fish and Wildlife Service in April 1991, which showed that the PCB concentration in the fish to be less than the FDA limit of 2 ppm.

    See responses to comments #73 and #41. Tables 39 and 40 (pages 107 & 110) indicate that fish consumption was a completed past exposure pathway and a potentially completed future exposure pathway.

#119. Page 102 - Table 36--Off-Site Drainage PCB Analyses at Neal's Landfill, February 2, 1983. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Fish sampling was conducted by the US Fish and Wildlife Service in April 1991, which showed that the PCB concentration in the fish to be less than the FDA limit of 2 ppm. In addition, analytical results from follow up sampling of sediments in 1988 in Richland Creek were non detectable for PCBs and in 1992 in Richland Creek ranged from non detect to 0.6 ppm (2.0 ppm for duplicate) for PCBs. Analytical results from follow up sampling of sediments in 1992 at Conard's Branch ranged from non detectable to 1.8 ppm for PCBs. Surface water samples were non detectable for PCBs in Conard's Branch and Richland Creek. Details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. 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 comments #73 and #41. The 1983 fishing advisory for Richland Creek, which resulted from analyses of 1982 sampling data, was lifted in 1989. The 1989 decision was based on more recent sampling data that indicated the PCB levels in fish were lower than the FDA action level of 2 ppm. For purposes of pathways analysis, the 1982 data were used to determine past exposures via ingestion of PCB-contaminated fish; the report appears on page 107 (Table 39). Since there appears to be a continuing flow of PCB contamination into Richland Creek in spite of the interim actions that have been taken (see #59), there is the potential that contaminant levels may once again become elevated and increase the levels of PCBs in fish and wildlife associated with the stream. Thus, a future, potential pathway of human exposure was designated for those who would consume fish taken from the creek (page 110, Table 40).

#120. Page 103 - Table 37--Caged Fish Stock PCB Sample Results, Neal's Landfill, September 1982. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Fish sampling was conducted by the US Fish and Wildlife Service in April 1991, which showed that the PCB concentration in the fish to be less than the FDA limit of 2 ppm.

    See response to #119.

#121. Page 103 - Table 38--On-Site Vegetation PCB Sample Results, Neal's Landfill, February 1, 1982. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. In addition, details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. 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 #73 and #41 regarding past exposures and MRLs, respectively. The discussion and Table 38 on page 103 of the PHA described PCB results of 1982 vegetation samples that were considered deer browse by the U.S. Fish and Wildlife Service. Health assessors interpreted those data to represent a past completed exposure pathway for persons who consumed wild game that roamed the site.

#122. Page 104--Ambient Air. Ambient air should not be considered a completed present and future exposure pathway. PCB concentrations in springs are not high enough to cause detectable concentrations in ambient air. PCBs in surface waters tend to bind to organic matter and particulates, thereby minimizing volatilization.

    ATSDR agrees with this comment (see response to #29). However, a future air exposure pathway may occur as a result of final remedial actions that will be taken at the site unless proper control procedures are implemented.

#123. Page 105 - The cited maximum levels of PCBs (21 ppm) in off-site water and sediment are incorrect. On p. 99 levels of 68 ppm were mentioned. What recent data supports a conclusion of only a "past potential exposure"? The site continues to leak at levels in excess of health concerns as ATSDR pointed out in its question on the high NPDES permit level. Because the Indiana Supreme Court supported a legal contract does not make the contamination less toxic.

    Maximum concentration reported in sediments associated with off-site areas of Neal's landfill was 68 ppm reported in 1980. The 38 ppm reported on the bottom of page 105 should read 68 ppm. These samples were taken before the removal action conducted in 1987-1988. The maximum level of 21 ppm cited by the commenter was from an area of Conard's Branch, upstream of the stream treatment facility (see Table 34, page 100); the source of the PCBs is unknown. There are indications from the FWS that sediments are being recontaminated. The extent of present and future human exposure will depend largely on the frequency and kinds of activity that occur in streams and lands affected by the site. Current data regarding levels of PCBs in aquatic species that might serve as food sources for humans were also not available. An assessment of human impact would require evaluation of such data. The appropriate agencies should evaluate ecological impact. For similar concerns at another site, see response to #59.

#124. Page 107 - Table 39--Completed Exposure Pathways for Neal's Landfill. Bases for number of exposed persons for the pathways are not identified. Exposure to off-site surface water and sediment in Conard's Branch and Richland Creek should not be identified as completed exposure pathways for the present and future. The remedial measures conducted at the site such as capping of the landfill, sediment removal in Conard's Branch, and the operation of spring treatment facility have limited the potential for exposure to PCBs. Indeed, these exposure paths are identified as present and future potential exposure pathways on page 109, 2nd paragraph. The pathways are not completed. Surface water and sediment samples taken in October 1992, showed minimal PCB concentration to be present in Conard's Branch sediments and non detectable in Richland Creek sediments. Surface water samples were non detectable for PCBs in Conard's Branch and Richland Creek.

    The ISDH confirms that the table contains an error with respect to completed pathways for ambient air. The table should indicate that the pathway was only likely completed in the past. See #123 regarding potential exposure pathways. See #56 regarding bases for number of exposed persons by pathway.

#125. Page 108 - The statement on the effectiveness of the treatment system to eliminate PCBs in the groundwater under base flow conditions before it leaves the site is incorrect. The system is required to handle only 1 cfs (cubic foot per second) to 1 ppb. No records show the proportion of water handled (or even the quantity). What is base flow? and does it all come through these springs.

Try to be a little more impartial and scientifically accurate. The levels of PCBs in the overflow basin are not indicative of the stream sediments. To cite 7.7 ppb when levels of 68 ppm have been detected does not indicate a situation of little concern. What about some of the other contaminants such as lead and vinyl chloride? A good assessment would also look at the additive and antagonistic effects of the mix of hazardous substances. To calculate each risk separately may produce a low risk, but cumulatively they are quite a body burden.

    The 68 ppm level of PCBs was detected in samples taken in 1980, before the implementation of interim remedial steps that included excavating sediments at the headwaters of Conard's Branch. The Stream Bank Project began in 1987 and ended in 1988. The levels detected in the basin (South Spring) during a 1992 sampling by the IDEM indicated a maximum level of 7.7 ppm (not the 7.7 ppb reported in the document). Similar levels were detected by Westinghouse (see Table 34, page 100). Overall, ATSDR believes that the levels reported in 1992 were representative of the sediment levels of PCBs at that time. Monitoring is continuing. Regarding the concern about mixtures and body burdens, ATSDR and ISDH do evaluate the possibility of combined contaminant exposures when there is a relevant pathway. In the case of sediments, the most likely exposure scenario would be related to human ingestion of fish or wildlife that bioaccumulate PCBs from the sediments. Based on observations during site visits, such an exposure scenario appears unlikely. However, if exposures were to occur, vinyl chloride and other solvents, unlike PCBs, do not bioaccumulate in fish or animals to any extent, if at all, and therefore would not be likely to increase body burdens of individuals who might consume fish and game associated with creek water. Although lead may accumulate to some degree in bones of fish, it is unlikely that ingestion of fish tissue will lead to increased human body burdens of lead. Thus, no cumulative body burden for vinyl chloride or lead is likely even if humans consume fish and game associated with the creek.

#126. Page 108 - Off-Site Groundwater Pathway. A hydrogeologic connection from the site to private wells has not been demonstrated.

    Similarly, a hydrogeologic connection from the site to private wells has not been ruled out.

#127. Page 109 - Richland Creek is still contaminated; it should be cleaned up. The creek should be posted until it's cleaned up.

    See response to #119. The state's routine monitoring of fish determines whether posting is required. Because of vandalism, posting has not proven to be a practical or effective way of warning the public of potential hazards associated with consuming fish from contaminated creeks and rivers.

#128. Page 109 - Off-site fish - Neal's Landfill. Concentrations of PCBs in fish in Richland Creek will be minimized because of the sediment removal in Conard's Branch and Richland Creek and the operation of the spring treatment facility which treats up to 1 cfs of spring water to less than 1 ppb. This was confirmed by the results of fish sampling conducted by the US Fish and Wildlife Service in April 1991, which showed that the PCB concentration in the fish to be less than the FDA limit of 2 ppm. In addition, sediment samples taken in October 1992, showed minimal PCB concentration to be present in Conard's Branch and non detectable in Richland Creek. Recent fish samples taken by IDEM show preliminary results of 0.7 ppm and 1.9 ppm in whole fish samples for creek chub and white sucker. In addition, fish samples taken from fillets of rock bass and white sucker were 0.076 ppm and 0.48 ppm respectively.

    See response to #127.

#129. Page 110 - Table 40--Potential Exposure Pathways for Neal's Landfill. Basis for number of exposed persons for the off-site groundwater pathway is not identified.

    The number of residential private wells within a 3-mile radius of the site (see exposed population column, Table 40) was multiplied by an estimated number of persons per household. A 1986 well user survey found 43 residential wells within 5,000 feet of the site (page 97). If there were three people per household, a total of 129 people could be exposed. Table 40 indicates 120 persons.

III.C.6. Winston-Thomas Facility Pathways Analysis

#130. Page 115 - Table 41--On-Site Abandoned Lagoon Total PCB Sample Results for Winston-Thomas Facility, March/April 1984. The analytical results may not be representative of current conditions. In addition, the EMEG comparison 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 #41 and #73.

#131. Page 116 - Table 42--On-Site Tertiary Lagoon Sludge PCB Sample Results, Winston-Thomas Facility, July 1982. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. 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 #41 and #73.

#132. Page 117 - Table 43--On-Site Tertiary Lagoon Core Sludge Total PCB Sample Results, Winston-Thomas Facility. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Ten samples were collected from the tertiary lagoon in the summer of 1992. The maximum reported dry weight PCB concentration was 2500 mg/kg in Sample M. The EMEG comparison 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 #41 and #73. Regarding core samples, the 1992 core sampling data noted by the commenter were apparently not available to the health assessors. However, the PCB level detected in 1992 in core sample M suggests that little change in concentrations of PCBs in core sludge has occurred since the mid-1980s (see Table 43). While the PHA did not propose direct exposure pathways involving the tertiary core sediments, the data do indicate that a continuing source of contamination exists and creates opportunities for off-site exposures. (See page 130, Table 49.)

#133. Page 118 - Table 44--On-Site Tertiary Lagoon Core Sludge & Clay PCB Sample Results, Winston-Thomas Facility, June 1983. With the exception of the clay samples for Core Locations E, G. and M, the data is the same as that presented in Table 43.

    As noted in #132, there has been little change in core levels of PCBs.

#134. Page 122 - Table 46--Off-Site Surface Water and Sediment Total PCB Sample Results for Winston-Thomas Facility. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Remedial measures conducted at the site included the removal of sediment from Clear Creek near the site. Analytical results from follow up sampling of surface water (1991) were non detectable for PCBs. Country Club Road where 0.50 ppm PCBs were detected in November 1991 is upstream of the Winston-Thomas Facility. This analytical result is greater than the results obtained near the facility and downstream of the facility. In addition, details should be provided regarding the exposure assumptions employed in the calculation of the EMEG comparison values from MRLs and their relevance to the Bloomington sites. The EMEG comparison value for water is tenfold less than the current drinking water MCL 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 #41 and #73 concerning EMEGs and use of past data. Regarding the sample for Country Club Road, the commenter is correct that there should have been some indication of the upstream nature of the sample either in Table 46 or in the narrative. Table 46 does provide sampling dates that provide a temporal perspective of the site history and activities. However, the fact that the health assessor did not indicate that the Country Club Road sample was upstream does not affect the conclusions that the assessor reached regarding completed or potential exposure pathways.

#135. Pages 123 & 124 - Table 47--Off-Site Fish PCB Sample Results for Winston-Thomas Facility. Analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Remedial measures conducted near the site included the removal of sediment from Clear Creek, a potential source of PCBs. Analytical results from follow up sampling of sediments (1988 and 1991) were less than 0.19 ppm and surface water (1991) were non detectable for PCBs.

    Regarding the use of past data for assessing current conditions, see response to #73. As noted by the commenter, the most recent sediment and surface water sampling results for Clear Creek appear to be from 1991. Those results reflect the positive effects of the interim remedial actions conducted at the site. However, the FWS has indicated that fish samples collected in 1992 downstream of the Winston-Thomas facility (locations not specified) had PCB levels higher than 3 ppm, suggesting that recontamination of sediment and surface water may be occurring and that routine consumption of fish from Clear Creek, if any, may pose an increased health risk. However, it remains unclear to ATSDR whether areas of Clear Creek affected by the site are routinely used by humans as a source of food. Based on observations made by ATSDR during site visits in 1993, such use appears unlikely. There is a need, therefore, for data on patterns of food consumption by humans who harvest from the areas of Clear Creek affected by the site. Additional sampling for current levels of contaminants in off-site sediment, water, and biota could be useful to agencies looking at effects on surrounding ecosystems.

#136. Page 125 - The sludge did not come from the Westinghouse facility.

    This comment is correct; the sludge came from the Winston-Thomas facility.

#137. Page 125 - Off-site fish--Winston-Thomas. This pathway should not be characterized as completed for the present and future. The evaluation of this pathway is based solely on pre-Interim Remedial Measures data, the most recent of which is from 1980. There are no post-IRM fish data to suggest that fish PCB levels exceed the FDA limit. Clear Creek sediments, a potential source, have been removed. Since post-interim remedial measures sediment samples indicate minimal PCB concentrations in sediments, it is unlikely that current fish samples would exceed the FDA limit. The characterization of this pathway as completed for the present and future should be deleted.

    See response to #135.

#138. Page 126--Ingestion of Wildlife from the Tertiary Lagoon. There is very little compelling evidence to included the consumption of wildlife that may have roamed on the Winston-Thomas Facility as a completed past, present, and future pathway.

    See response to #135.

#139. Page 127 - Table 48--Completed Exposure Pathways for Winston-Thomas Facility. The off-site fish pathway should not be identified as complete for the present and future. A potential source of PCBs in Clear Creek, the sediments, were removed during remedial measures in 1987. Analytical results from follow up sampling of sediments (1988 and 1991) were less than 0.19 ppm and surface water (1991) were non detectable for PCBs.

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.

No compelling evidence has been presented to included the consumption of wildlife that may have roamed on the Winston-Thomas Facility as a completed past, present, and future pathway.

Bases for number of exposed persons for the pathways are not identified.

    See response to #135 for information concerning the potential ingestion of fish and wildlife. The issue of sludge is addressed in #27 and #37. The difficulty of estimating exposed persons per pathway is addressed in #56.

#140. Page 128--Off-site Sediment. The results for the July 1988 sampling event (actual sampling occurred 6/30/88) were non detectable for PCBs for all ten samples. In addition, IDEM sampled sediment in Clear Creek in November 1991. The concentration of PCBs in the four sediment samples from the creek near the Winston-Thomas Facility ranged from non detectable to 0.19 ppm.

    The commenter is correct. All of the June/July 1988 sediment samples within the first indicator area (within 300 feet of Gordon Pike) were non-detect for PCBs; one sample in the second indicator area (12 miles south of Gordon Pike) contained 12 ppm PCBs (see page 121). The commenter is correct regarding the data from the November 1991 sediment sampling. As noted in #8 and #25, however, there is some evidence of continued leaching and recontamination.

#141. Page 129 - PCB levels in Clear Creek of 0.19 ppm is almost 400X MCL for drinking water and is high enough to be considered as a significant health risk.

    The 0.19 ppm is actually a sediment level, not a surface water level. If the 0.19 ppm were in a drinking water supply, health agencies would increase their levels of health concern. However, Clear Creek is a surface water body, and it is not routinely used as a source of potable water (i.e., 1 to 2 liters of water per day). Therefore, a health assessor will not directly compare the contaminant concentration with a drinking water standard to reach a health conclusion.

#142. Page 129 - Off-site Groundwater--Private Wells. A hydrogeologic connection from the site to private wells has not been demonstrated. The area near the site is served by the municipal water supply.

    The possibility of a hydrogeologic connection has not been eliminated. Because there may still be some private wells used for potable water, as noted on page 129, groundwater was considered a component of a potential pathway for exposure in the past, present, and future.

#143. Page 130 - Table 48--Potential Exposure Pathways for Winston-Thomas Facility. Bases for number of exposed persons for the On-site/Off-site Ambient Air and Off-site Groundwater pathways are not identified.

    For this table (actually Table 49), the health assessor estimated the number of people potentially exposed via ambient air by identifying the number of residences within a certain radius of the site and adding a portion of the estimated number of individuals who obtained sewage sludge from the facility for home gardening. The number of persons potentially exposed via the groundwater pathway was estimated from the number of private wells within a 5,000-foot radius of the site (i.e., 3 per household X 40 wells = 120).

III.C.7. Public Health Information

#144. Page 134 - Exposure Assumptions. The exposure assumptions on page 134 are not placed in perspective, and the concept of daily exposure is not justified. The report provides inadequate documentation as to how these assumptions are used to calculate exposure, and how these calculated exposure levels are used to determine whether or not a potential risk or hazard exists.

    The exposure assumptions used are consistent with ATSDR PHA guidance. The commenter is correct, however, in suggesting that these guidelines should be adjusted, based on site-specific factors, to obtain an accurate perspective on exposure and, therefore, on public health implications. Because sampling data in many cases were not considered sufficient to determine extent of contamination, ATSDR asked ISDH to estimate public health impact conservatively.

#145. Page 135 - Table 50--Summary of Chemicals of Concern by Site and Media. The bases for chemicals of concern other than PCBs is not clear nor does there appear to be sufficient evidence presented in the report to include additional chemicals of concern. It is stated on page 136 that it is "highly unlikely" that chemicals would contaminate private wells. Moreover, with few exceptions, the evaluations of the chemicals in the following pages determined that no adverse health risks are expected from exposure to the chemicals at their detected levels. This is true even when the detected levels of the chemicals used for comparison to health-based criteria are the maximum concentration which were ever detected and obtained prior to remedial measures were conducted at the sites.

(Editor's Note: The following comments relate to specific sites cited in Table 50 of the PHA and addressed in the previous paragraph.)

  • 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 remedial measures such as the clay cap and security fence. The on-site pond sediment has been removed.
  • Lemon Lane Landfill -- The on-site subsurface soil has been isolated by 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 remedial measures such as the clay cap. This evidenced by the ambient air sampling conducted after the completion of the remedial measures.
  • Winston-Thomas Facility -- The impact on off-site sediment has been minimized by remedial actions such as the removal of contaminated sediments from Clear Creek.
        Table 50 (page 135) is the same as the summary on page 13 of the PHA. ATSDR agrees with the commenter that the interim actions have reduced releases from the site and have tended to reduce or prevent human exposures to contaminants associated with the sites. Permanent remedies should further reduce exposures or eliminate them altogether. This table, however, was intended only to display the contaminants of concern for each of the sites and was not intended to make the distinction of when or if exposure pathways were, are, or will be completed. See also response to comment #38 (re: page 13 table).

    #146. Page 139 - Is chromium(VI) a carcinogen? Strange that this is not mentioned here

      Yes, hexavalent chromium (CrVI) is considered to be a human carcinogen based largely on occupational exposures to CrVI-containing aerosols and dusts in industries that process or grind metals. The primary effects of such exposures have been associated with nasal and lung cancer and other respiratory damage due largely to the very acid nature of the aerosols that are generated. Page 139 of the PHA contains a discussion of the chromium's ability to cause cancer under these exposure conditions. However, there is little evidence that levels of CrVI that might be found in the environment pose a threat to humans under feasible exposure scenarios, because most forms of chromium in the environment tend to be trivalent (CrIII). The valence state for chromium was not specified in the PHA. Chromium was probably analyzed as total chromium, which most likely includes mostly CrIII. Chromium is a required element for normal physiological function and is a component of almost all multi-vitamin preparations.

    #147. Page 140 - The discussion of dioxin here and in any site where detected or possible from site history needs to be re-done in light of EPA's recent revision on dioxin toxicity.

      The discussion of dioxins on page 140 is correct. There is nothing in EPA's draft dioxin reassessment that requires changing the discussion. See response to #82.

    #148. Page 141 - The occurrence of 122 ppb of lead which exceeds the MCL of 50 ppb should be sufficient to indicate a situation of concern for health risks. Although ATSDR has not established an RfD (reference dose) for a substance, this does not mean that hazardous substances contaminating a water resource are of little concern.

      If this concentration of lead were in a drinking water supply, health agencies would certainly increase their level of health concern. However, surface water near Neal's Landfill is not routinely a source of potable water (i.e., 1 to 2 liters of water per day). Therefore, a health assessor does not directly compare the contaminant concentration with a drinking water standard to reach a public health conclusion.

    #149. Page 142 - Polychlorinated Biphenyls (PCBs). This section cites the ATSDR Draft Toxicological Profile for Selected PCBs (presumably the October 1991 draft) as the source of information reported in this paragraph. 1) ATSDR's final toxicological profile is available (ATSDR, 1993); 2) ATSDR's 1993 final profile no longer states that exposure to alcohol or tobacco smoke can enhance susceptibility to the adverse health effects caused by PCB exposure. Furthermore, general exposure to antibiotics does not put someone at additional risk. ATSDR (1993) states that children who are taking the antibiotic novobiocin may have increased sensitivity to PCBs due to novobiocin's interference with glucuronyl transferase (this would intervene in the metabolism and excretion of PCBs). This statement is specific to novobiocin and hardly supports a general conclusion that antibiotics increase sensitivity to PCB exposure.

      A final version of the Toxicological Profile for Selected PCBs (TP-92/16) became available after the completion of the writing of this section of the PHA. ATSDR agrees that the statement is specific to novobiocin and may not apply to other antibiotics.

    #150. Page 143--PCBs in blood fats. This statement implies that PCBs affect blood lipids. In fact, PCB concentrations are correlated with blood lipid levels because PCBs are lipophilic chemicals.

      ATSDR agrees that while associations have been demonstrated, there is no clear evidence of causation. As cited in ATSDR's 1995 draft Toxicological Profile on Selected PCBs, "Increased levels of serum triglycerides and cholesterol have not been reported consistently in workers with long-term exposure to PCBs... ." The significance of the reported changes in serum triglycerides and cholesterol in humans occupationally exposed to PCBs is unclear and could be due to partitioning phenomena" (PHA page 83, last paragraph; page 84, first paragraph). Furthermore, the expert health panel that met in Bloomington in September 1993 indicated that the relationship once thought to be causal is now viewed as artifactual (Proceedings of the Expert Panel Workshop To Evaluate the Public Health Implications for the Treatment and Disposal of Polychlorinated Biphenyls-Contaminated Wastes (September 13-14,1993).

    #151. Page 143 - Polychlorinated Biphenyls (PCBs). In the final toxicological profile for selected PCBs, ATSDR (1993) states:

  • "Associations between serum PCBs and hepatic indices in environmentally exposed populations are generally inconclusive." (page 45, first sentence).
  • "Increased levels of serum triglycerides and cholesterol have not been reported consistently in workers with long-term exposure to PCBs .... The significance of the reported changes in serum triglycerides and cholesterol in humans occupationally exposed to PCBs is unclear and could be due to partitioning phenomena" (page 83, last paragraph; page 84, first paragraph).
  • "Dermal lesions including skin irritation, chloracne, and pigmentation of nails and skin have been observed in humans following occupation exposure to relatively low levels of PCBs, but time to recovery, effect levels, and possible contribution of contaminants cannot be evaluated with the existing information." (page 85, first paragraph).
  • Occupational studies provide inconclusive evidence of PCB-related cancer...Study limitations and inconsistent findings among studies contribute to the inconclusive results." (page 92, first paragraph).
      The above statements will be incorporated, where appropriate, in future PHAs that address PCBs as a chemical of concern.

    #152. Page 143 - Cancer and reproductive effects. In fact, cancer and reproductive effects of PCBs in humans have been extensively studied and there is no evidence that PCBs cause such effects in humans. There is an extensive occupational exposure data base as well as data for less-exposed subpopulations. Collectively, the only adverse health effect 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 ever been documented.

      The expert health panel convened by ATSDR in September 1993 concluded that the data on carcinogenicity from human studies are limited and equivocal. Several occupational studies from around the world have reported positive associations between PCB exposure and excess risk of mortality from cancer; others have failed to find associations. Among the studies reporting positive associations, no consistent pattern of excesses of anatomic site-specific cancers among the various worker cohorts has been demonstrated. Similarly, the expert panel also concluded that while human epidemiologic studies suggest reproductive effects (cognitive intelligence and attention behavior decrements), there is a need for more definitive studies. The panel stated that it was more difficult to document functional effects than structural effects, given the current level and type of existing medical records and public health surveillance systems.

    #153. Page 144 - Table 51--Comparison of Estimated Exposure Dose to Health Guidelines for PCBs in Fish. As stated for the fish data presented in the specific sections for each site, analytical results that are not representative of current conditions should not be used as a comparison value to demonstrate a potential health risk. Remedial measures conducted at Bennett Stone Quarry and Winston-Thomas removed a potential source of PCBs by cleaning the sediment from Stout's Creek and Clear Creek, respectively, in the vicinity of the sites. Analytical results from sampling of sediments in Stout's Creek in 1988 and 1993 were non detectable for PCBs. Analytical results from sampling of sediments in Clear Creek in 1988 and 1991 were less than 0.19 ppm for PCBs. In fact when the most recent Neal's Landfill data is used for comparison (fish sampling in Richland Creek, US Fish and Wildlife Service April 1991), which showed that the PCB concentration in the fish was less than the FDA limit of 2 ppm, the fish advisory on Richland Creek was lifted.

      Data displayed in Table 51 were used for past exposure estimations and were also used by ISDH as the basis for fish advisories. The fish advisory for Richland Creek was lifted in 1989; the advisory for Clear Creek remains. The FWS has indicated in a letter to ISDH that some recontamination of off-site sediments associated with Bennett Stone Quarry, Winston-Thomas Facility, and Neal's Landfill has occurred and may impact fish and wildlife. See also #8 and #25.

    #154. Page 146 - Table 52--PCB Multi-Media Ingestion Exposure Dose and Cancer Risk Summary Table for All Consent Decree Sites. The bases for this table is not evident and only minimal indication is provided on 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 are 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 (p 150). Additional details regarding how the cancer risk determinations were made must be presented.

      See response to #42 regarding the basis for cancer risk screening levels.

    This presentation of cancer risk severely misrepresents conditions at the sites. Specifically:

  • Bennett's Quarry - Subsurface soil - "high increase." The site has been capped and fenced. There is no pathway for exposure to subsurface soil; thus, there can be no risk.
        This is a past estimate of risk from contacting surface soil prior to any remediation.
  • Neal's Dump, subsurface soil - "moderate increase." Same comment.
        This, too, refers to a past estimate of risk.
  • Neal's Dump, groundwater - "very high increase." There is no potable water use or any other pathway of exposure to on-site groundwater. Off-site potable wells are clean. There is no completed exposure pathway and thus no risk.
        Hydrogeologic connections have not been ruled out.
  • Winston-Thomas, off-site sediment - "high increase." The report itself characterizes this pathway as only a potential past exposure pathway (page 122, Table 49). Sediments were removed from Clear Creek, thereby removing the source. There is no complete pathway, and thus no risk.
        Off-site sediment in this case may also refer to the sewage sludge taken and used in residential gardens. The locations and amounts of contaminants have yet to be characterized fully.

    #155. Page 147--Maximation of cancer risk. Extremely conservative assumptions are presented for the estimation of cancer risk: children exposed to sediments five days per week; sediments contain the maximum PCB concentration detected at each site; 100 percent of the sediment ingested is available for absorption by the gastrointestinal tract; and 100 percent of the contaminated sediments are absorbed through the skin. These exposure assumptions and modeled results are not validated by the health studies conducted in the Bloomington area. As concluded by this report for each of the sites "Community-specific health outcome data do not indicate that the site has had an adverse impact on human health" (pages 164-168).

      The authors noted that the assumptions they used were for a worst-case exposure scenario and for conservative estimates of toxicity potency. Applying these criteria assured that ATSDR would provide a further review of the information and would judge the human health impact at each location. Overall, ATSDR agrees with the commenter that with the exception of the noted subsets of the general population (metal reclaimers, home vegetable gardeners and consumers of their produce, and workers in the Westinghouse facility), exposures to the general public were and are minimal.

    #156. Page 147--Dermal Exposure. The use of 100% dermal absorption is not warranted. USEPA dermal exposure guidance cites a range of 0.6 - 6% for PCBs. The assumption of 5 day/week exposure to sediment is unrealistic given the remote nature of these sites and the lack of physical attributes that would attract children.

      As noted previously, conservative assumptions are appropriate for screening. ATSDR agrees that such exposures to PCBs in environmental media are very unlikely to result in 100% absorption.

    #157. Page 147--Inhalation exposure. The inhalation LOAEL should be properly referenced since it is much lower than effect levels indicated by most studies. The NIOSH (National Institute for Occupational Safety and Health) value should not be included at all since it is not health based, but is based on analytical capabilities. A more appropriate value which is based on epidemiologic information would be the OSHA (Occupational Safety and Health Administration) PEL (permissible exposure limit) and/or the ACGIH (American Conference of Governmental Industrial Hygienists) TLV (threshold limit value), which are in the range of 500 to 1000 ug/m3.

      The commenter is correct regarding the OSHA PELs and ACGIH TLVs. The 3 µg/m3 level cited on page 47 is incorrectly listed as a LOAEL. However, the 3 µg PCBs/m3 is in the range used by several states in regulations or guidelines for PCBs in ambient air.

    #158. Page 147--Health effects on scavengers and trespassers. The acknowledgment should be made that the population potentially exposed and at risk, such as scavengers and trespassers, have no actual indication of elevated exposure to PCBs and no indication of adverse health effects. This fact should be featured more prominently throughout the document and much less emphasis should be given to hypothetical worst case evaluations of potential exposure and maximization of cancer risk as stated in the second and third paragraphs.

      See responses to comments #21 and #24.

    #159. Page 151--Health outcome data evaluation. Collectively the studies discussed in this section demonstrate that the general population in Bloomington is no more exposed to PCBs than the general U.S. population and no more at risk of adverse health effects. This fact should be emphasized throughout the document rather than emphasizing hypothetical worst-case evaluations of exposure and risk.

      See responses to #21 and #24.

    #160. Page 161--Risk Assessment. Although ISDH states that no risk assessment will be performed as part of this project, some sort of risk assessment must have been done to derive the cancer risk estimates cited previously. If this analysis is to be included, much greater detail should be provided. However, if the document is to remain true to its stated purpose and represent only a pathway analysis, the cancer risk portions of the evaluation should be deleted.

      An ATSDR PHA is a qualitative evaluation of the potential public health implications posed by past, present, and future exposures, if any. We do not perform risk (probabilistic) calculations. The cancer screening levels we use to determine contaminants of concern at various locations are based on EPA slope factors and generic exposure factors provided in the ATSDR PHAGM. See response to comment #42.

    III.C.8. Conclusions

    #161. Page 164 - At Anderson Road, it is surprising that a concern for methane, a non-toxic gas is expressed, but the presence of a "soup" of solvents was detected in the gas sampling raises (with) no question.

      It is quite common for sanitary landfills to generate sufficient methane gas to be of health concern. Methane is a volatile organic compound, so it is surprising that methane was not detected in the soil gas samples. Soil gas samples were taken one time, on site, around the time that the site was remediated. Sample depths and locations were not provided, so it is not possible to determine the significance of these data. The public is not exposed to the subsurface soils at this site. The groundwater is being monitored for VOCs, SVOCs, and inorganic chemicals, and through 1993 none had been detected.

    #162. Page 164--Anderson Road Conclusions, Item 3. It is stated that specific sub-groups "may be exhibiting signs and symptoms of adverse health outcome due to site-related exposures"; however, the sub groups are not identified nor is there any evidence in the report (past health studies have looked at specific subgroups) to indicate that this is indeed the case. In fact this report acknowledges that the population potentially exposed and at risk, such as scavengers and trespassers, has no actual indication of elevated exposure to PCBs and no indication of adverse health effects.

      See responses to #21 and #24.

    #163. Page 164 - At Bennett's the presence of free PCB oils represents a long-term source of contamination to Stout's Creek. The accumulation in fish is evidence of the ongoing leakage.

      See response to #66.

    #164. Page 164--Bennett Stone Quarry Conclusions, Item 2. The conclusion that a health hazard exists from the consumption of fish from Stout's Creek is based on analytical results that do not reflect current conditions. Remedial measures conducted at the site included the removal of sediment from Stout's Creek near the site. Analytical results from follow up sampling of sediments in 1988 and 1993 were non detect for PCBs.

      See response to #59. The question of whether humans use fish (and wild game) found in those portions of the Stout's Creek and Bean Blossom Creek areas as food sources is important. If yes, then Conclusion 2 and Recommendation 1 for Bennett's on page 169 would be appropriate.

    #165. Page 164--Bennett Stone Quarry Conclusions, Item 4. A hydrogeologic connection from the site to private wells has not been demonstrated.

      This comment appears to refer to Bennett's Conclusion 3. Private wells may still be in use. As noted in #68, available data do not rule out a hydrogeologic connection for the deeper aquifers, and the wells have been sampled only for PCBs. Therefore, ISDH designated this pathway and any health hazards associated with the pathway as indeterminate.

    #166. Page 165--Bennett Stone Quarry Conclusions, Item 5. It is stated that specific sub-groups "may be exhibiting signs and symptoms of adverse health outcome due to site-related exposures"; however, the sub groups are not identified nor is there any evidence in the report (past health studies have looked at specific subgroups) to indicate that this is indeed the case. Moreover, as acknowledged in this report that the population potentially exposed and at risk, such as scavengers and trespassers, has no actual indication of elevated exposure to PCBs and no indication of adverse health effects.

      See responses to #21 and #24.

    #167. Page 165--Lemon Lane Conclusions, Item 4. It is stated that specific sub-groups "may be exhibiting signs and symptoms of adverse health outcome due to site-related exposures"; however, the sub groups are not identified nor is there any evidence in the report (past health studies have looked at specific subgroups) to indicate that this is indeed the case. Furthermore, this report acknowledges that population potentially exposed and at risk, such as scavengers and trespassers, has no actual indication of elevated exposure to PCBs and no indication of adverse health effects.

      See responses to #21 and #24.

    #168. Page 165--Conclusions, Lemon Lane Landfill. Although Westinghouse now claims Detmer Spring is sourced from the old Westinghouse Plant run-off, (This does decrease the concern for the multiple exits from the site and the case for in-place closure is simpler.) Detmer Spring is still a major release of hazardous substances to the environment. Does the ATSDR concern change as Westinghouse redefines the sources of contamination? What are the health concerns for the mix of contaminants in Detmer?

      If, indeed, we redefine the source of contamination, it will have no impact on the public health conclusions reached by a health agencies review of environmental contaminant data. Pages 63, 64, 67, and 69 contain displays and discussions of the data for Detmer Spring. Off-site surface water and sediment are categorized as potential past, present, and future exposure pathways via dermal contact and incidental ingestion.
      During the consideration of health concerns at any location, we consider epidemiologic and toxicologic data of the individual substances and of the substances in combinations. Considerations include levels of exposure, effects of exposure, and circumstances of exposure. We review this information in the context of how exposures may occur in the area of interest. We then develop feasible exposure scenarios that reflect the manner in which individuals come in contact with the contaminants, who is likely to be exposed, how frequently and for how many days/months/years exposures will occur, and the known effects and levels of effects of substances and combinations of substances detected. Considering all of the above, none of the feasible exposure scenarios is likely to result in adverse health effects at this location, now or in the near future.

    #169. Page 165 - The EPA determined that levels (58 ppm) exceeding those requiring clean-up (50 ppm) did not constitute a health threat. Considering that the point of highest contamination behind Hinkle's at Third Street is a common play area for neighborhood children, the likelihood of contact may be high and the threat greater than EPA calculated.

      The finding of 58 ppm could indicate ongoing contamination of the Illinois Central Springs area (see Table 19 and discussion on pages 67 and 68). A duplicate sample (i.e., a sample taken at the same location at the same time as the sample showing 58 ppm) contained 21 ppm, a level more consistent with other samples from this area. All other samples had levels less than 20 ppm. Based on the available sampling data and review of the environmental settings and of the nearby populations, ATSDR does not expect that any intermittent contact that may occasionally occur at the springs associated with Lemon Lane Landfill, including those behind Hinkle's Restaurant, would be sufficient to result in exposures leading to increased body burdens or to cause adverse health effects in the general population. Because the 1991 data may not represent current conditions, ISDH recommended that access to these areas be minimized or prevented. If more recent data concerning human activities and environmental contamination become available, ATSDR will review them.

    #170. Page 165--Lemon Lane Conclusions, Item 5. To state that high levels of PCBs were found in springs and streams associated with the Lemon Lane Landfill is misleading. The majority of the samples did not contain detectable levels of PCBs ( < 0.1 ppb). The samples that did contain detectable levels of PCBs had low or sub-ppb levels of PCBs.

      Table 19 on page 67 summarizes the most recent (June 1991) off-site sediment data. PCB concentrations ranged from 0.2 to 58 ppm. See response to comment #169 for further discussion.

    #171. Page 166--Neal's Landfill Conclusions, Item 2. This statement is based on outdated information (i.e. pre-interim remedial measures fish data). There is no evidence that anyone actually ate more than one meal per week of fish obtained from Conard's Branch or Richland Creek in the area of elevated PCB levels. In fact, in these areas the streams do not support a sufficient population of edible-size sport fish. Recent data show fish PCB levels are less than the FDA limit.

      The commenter is correct that the first part of the conclusion does reflect past fish data and past potential exposures if fish were caught and consumed. However, the issues raised by the commenter regarding the extent, if any, of fish consumption (as well as wild game consumption) at these locations are important for establishing real rather than theoretical risks of exposure and health hazard. As indicated in response to comment #135 concerning fishing in Clear Creek, obtaining reliable data and information about current and past use of these streams for obtaining edible fish and game is recommended.

    #172. Page 166--Neal's Landfill Conclusions, Item 3. One private well has shown a potential hydrogeologic connection to an off-site monitoring well, not the site.

      Page 108 of the PHA points out that information on the depths of the residential wells near the site and the numbers and depths of aquifers below the site were not provided for review and may not exist. To be protective of public health, ISDH chose to avoid ruling out this possible exposure pathway until there are definitive data available.

    #173. Page 166--Neal's Dump Conclusions, Item 4. It is stated that specific sub-groups "may be exhibiting signs and symptoms of adverse health outcome due to site-related exposures"; however, the sub groups are not identified nor is there any evidence in the report (past health studies have looked at specific subgroups) to indicate that this is indeed the case. In fact it is acknowledged in this report that the population potentially exposed and at risk, such as scavengers and trespassers, has no actual indication of elevated exposure to PCBs and no indication of adverse health effects.

      See responses to #21 and #24.

    #174. Page 166--Neal's Landfill Conclusions. The conclusions discount the permeability of the alluvial sediments between Neal's Dump and the White River and the surface run-off in the ditch. One is a current threat, and both are future threats to a water and food source. At Neal's Landfill the current NPDES permit level for PCBs is not protective of human health and the environment. To say less is to question the level of concern in both the MCL and FWS limits.

      Regarding Neal's Dump (Conclusion 3), the surface contamination has been removed from this site, and a soil cap was placed over the dump area. Sampling of off-site sediment in the north-northwest ravine stream in 1983 in the same location or downstream of an area that had levels as 275 ppm in 1976 did not detect PCBs. Furthermore, during a site visit, the ditch area appeared to be very overgrown and did not seem to offer opportunities for frequent, direct public contact and possible exposure. Unless there has been substantial recent off-site migration of PCBs via surface runoff, there would appear to be little or no impact on the White River. Results of groundwater monitoring suggest that levels of PCBs reaching the White River, if any, would be inconsequential from a public health perspective.
      Regarding Neal's Landfill (conclusions 4, 5, and 6), the effectiveness of the NPDES permit to protect human health and the environment has been the subject of numerous citizen concerns. The available data do indicate that Conard's Branch and Richland Creek are being recontaminated. When the sediment removal project was completed in October 1988, the analysis did not detect any PCBs. The most recent sediment samples, taken in October 1992, show concentrations ranging from non-detect to 21 ppm. Thus, the current NPDES permit may not be sufficient to prevent recontamination of the streams. It is ATSDR's opinion that those levels would not pose a direct threat to humans, given most feasible exposure scenarios of direct contact and direct ingestion. However, there is a concern that routine human ingestion of fish and wild game from areas affected by Neal's Landfill could lead to elevated exposures. Similarly, cattle drinking in the streams could serve as an elevated source of PCBs to those drinking milk and eating meat from the cattle. Thus, for Neal's Landfill Conclusion 4, the use of the word may is appropriate. Exceeding any regulatory value, whether it is the NPDES permit level or an MCL, does not automatically indicate that adverse human health effects will occur. Effects on human health following exposure, if any, depend on frequency and extent of exposure, manner of exposure, and the toxic potential of the contaminant. The use of an MCL as an indicator for health effects associated with Neal's Landfill springs is not appropriate, since humans do not consume the surface water daily, frequently, or extensively. As noted in the response to #171, there is a need for current information and data on fish and fishing patterns. Even if human health may not be at increased risk, appropriate agencies should evaluate the potential environmental impacts of recontamination.

    #175. Pages 166 & 167--Neal's Landfill Conclusions, Items 4, 5 & 6. The conclusion that the NPDES permit limit for Neal's Landfill Treatment Facility may not be protective of human health or the environment is not supported. Analytical results from follow up sampling of sediments in 1988 in Richland Creek were non detect for PCBs and in 1992 in Richland Creek ranged from non detect to 0.6 ppm (2.0 ppm for duplicate) for PCBs. Analytical results from follow up sampling of sediments in 1992 at Conard's Branch ranged from non detect to 1.8 ppm for PCBs.

      See response to #174.

    #176. Page 167--Neal's Landfill Conclusions, Item 7. It is stated that specific sub-groups "may be exhibiting signs and symptoms of adverse health outcome due to site-related exposures"; however, the sub groups are not identified nor is there any evidence in the report (past health studies have looked at specific subgroups) to indicate that this is indeed the case. In fact this report acknowledges that the population potentially exposed and at risk, such as scavengers and trespassers, has no actual indication of elevated exposure to PCBs and no indication of adverse health effects.

      See responses to #21 and #24.

    #177. Page 167--Winston-Thomas Facility Conclusions, Items 1 & 3. Because of the quality of Clear Creek and the types of fish present, it is unlikely that subsistence fishermen use the creek. The conclusion that the sediment and surface water of Clear Creek are contaminated at levels of health concern are based on analytical results that do not reflect current conditions. Remedial measures conducted at the site included the removal of sediment from Clear Creek near the site. Analytical results from follow up sampling of sediments (1988 and 1991) were less than 0.19 ppm and surface water (1991) were non detectable for PCBs.

      Regarding sewage sludge (Conclusion 1), please see response to #37. Regarding Conclusion 3, the most recent sediment and surface water sampling results for Clear Creek appear to be from 1991. If 1995 levels are the same, ATSDR would agree with the commenter that Conclusion 3 and Recommendation 4 on page 170 may not be appropriate even if individuals use the creek occasionally for such recreational activities as swimming and wading. However, the FWS has indicated that fish samples collected in 1992 downstream of the Winston-Thomas facility had PCB levels in excess of 3 ppm, suggesting that recontamination of sediment and surface water may be occurring and that routine consumption of fish from Clear Creek may pose an increased health risk. It remains unclear to ATSDR, however, what kinds of fish and game are in Clear Creek in areas affected by Winston-Thomas and how often humans eat these fish and the game from the area. Without answers to the latter questions, ATSDR will not be able to reach a definitive conclusion regarding the public health impact of the Winston-Thomas site in its current status. Similarly, without data on current levels in sediment and in fish and animals affected by Winston-Thomas, agencies that evaluate impact on the environment and on ecosystems will likewise not be able to reach meaningful conclusions.

    #178. Page 167--Winston-Thomas Facility Conclusions, Item 2. A hydrogeologic connection from the site to private wells has not been demonstrated.

      While it is true that a hydrogeologic connection from the site to private wells has not been demonstrated, there are also no data to show that a hydrogeologic connection does not exist and will never be present. Furthermore, there appears to be some question regarding use of private wells in the area despite the availability of municipal water supplies. Until these questions and issues are resolved, ISDH has designated this pathway as a potential pathway and an indeterminate health hazard.

    #179. Page 167 - What about the impact on transient wildlife and the potential for off-site transport to other sites, organisms, and systems? Duck hunters nationwide now share in our problem.

    At Winston-Thomas some concern for the off-site transport of PCBs by transients and the impact on a wider population from release to other systems and consumption by hunters needs evaluation.

      See response to #6.

    #180. Page 167--Winston-Thomas Facility Conclusions, Item 4. It is stated that specific sub-groups "may be exhibiting signs and symptoms of adverse health outcome due to site-related exposures"; however, the sub groups are not identified nor is there any evidence in the report (past health studies have looked at specific subgroups) to indicate that this is indeed the case. In fact it is acknowledged in this report that population potentially exposed and at risk, such as scavengers and trespassers, has no actual indication of elevated exposure to PCBs and no indication of adverse health effects.

      See responses to #21 and #24.

    III.C.9. Recommendations

    #181. Page 169 - Recommendations

    • Monitoring wells at Anderson Road LF are MW-3, 4, 5, 6. All show some degree of leachate presence and need to be monitored frequently to determine the release of hazardous substances.

      According to the data received from the Monroe County Health Department, there are 3 monitoring wells (MW) (see pages 31, 32, and A-31) and 6 private wells (W) around the Anderson Road Landfill. The MW appear to be routinely monitored, and no contamination has been detected so far. Recommendation 1 on page 169 contains a typographical error. The recommendation should have referenced private wells W-1 and W-6, which are down gradient and are located in the state park, rather than using the designation MW. We do not know the functions of these wells, but we assume, for the purposes of this PHA, that they are used as sources of potable water.

    • At Bennett's the presence of free PCB oil demands a heightened vigilance for mobilization to surrounding surface and groundwater.

      See response to #66.

    • At Lemon Lane LF (Landfill) the presence of numerous contaminants requires an expanded analyte list. Landfills do not contain a homogenous trash, and the leakage from this site and others requires a wider concept of concern and monitoring extent.

      Sampling of groundwater monitoring wells during 1982-1983 and associated springs in July and December 1982 and to some extent in November 1991 did include analysis for substances other than PCBs, including VOCs, SVOCs, metals, and pesticides. Please see discussion and tables on PHA pages 61-67. Substances present at levels exceeding ATSDR CVs and therefore requiring further evaluation appear in Table 8 (page 66). Substances whose concentrations were less than ATSDR CVs were excluded from further discussion.

    • Also, if the uncontrolled effluent from Lemon Lane requires prevention of human exposure the site is a clear and present danger which demands immediate remedies.

      While ATSDR agrees with the commenter that it is desirable from the public's point of view to provide quick remediation at all sites where human exposures may be occurring, ATSDR does not agree that available data suggest that a "clear and present danger" exists. Based on the available sampling data and a review of the settings and of the nearby populations, ATSDR does not expect the intermittent contact that may occur at the springs near Lemon Lane Landfill to be sufficient to result in exposures that would lead to increased body burdens or would cause adverse health effects. ATSDR will review any new data or information that suggest significant exposures are or will be occurring.

    #182. Page 169--Lemon Lane Landfill Recommendations 1 and 2. Recommendations regarding the sampling of private wells appears to be unwarranted because, as stated in the report (page 53), all local residents are served by the municipal supply.

      If in fact the last household has now been connected to the municipal water supply, that would eliminate the drinking water pathway. However, ATSDR has occasionally found that people with private wells, even after being connected to municipal water supplies, will continue to use their private wells for outdoor uses such as watering the garden or yard or washing the car and even for drinking. Thus, some exposures may still occur. Recommendation 1 suggests that "individuals using private wells for any purpose should have their well tested... ." ATSDR will be happy to review any new data and information.

    #183. Page 170 - The ground and surface contamination represent a future impact on the White River, a food and drinking water resource. The ditch soil represents immediate threats to humans through direct contact, and a direct impact in the White River requiring response.

      See response to #174.

    #184. Page 170--Neal's Dump Recommendation 2. Neither Westinghouse nor any of the government agencies have documentation of a contaminated ditch that needs remediated at Neal's Dump. It is not clear what is meant by this recommendation. The site is surrounded by a fence and the landfill has a soil cover to prevent exposure to the landfill contents.

      See response to #174.

    #185. Page 170--Winston-Thomas Facility Recommendation 4. The basis for this recommendation is not clear since the most recent analytical data for Clear Creek samples of sediments (1988 and 1991) were less than 0.19 ppm and surface water (1991) were non detect for PCBs.

      See response to #177.

    #186. Page 170 - At Winston-Thomas some concern for the off-site transport of PCBs by transients and the impact on a wider population from release to other systems and consumption by hunters needs evaluation. Also, the extent and impact of biological degradation needs assessment. Even if it does occur, is the rate so slow that volatilization, and transient accumulation may be significant and yield severe negative effects. This should be one of the studies included in the next section.

      See response to #6 with regard to hunters. Regarding the issue of "natural degradation," ATSDR expects that the "natural degradation" of the PCBs in the lagoon sludges and core sludges will indeed be relatively slow (i.e., it will take years). However, from a public health perspective, unless humans gain access to the contaminated sludges that are present or to contamination that escapes from the site under conditions that lead to significant exposures, no public health threat is apparent. Data on human activities that indicate how often and under what circumstances exposures occur as well as levels of exposure that can feasibly occur will determine the degree of hazard posed by the site. Because of the potential ecological as well as human impacts, ATSDR and ISDH encourage environmental agencies and researchers to continue research in the area of biodegradation and bioremediation technologies.

    #187. Page 171 - All Sites--Recommendation 2. This recommendation appears unnecessary given the availability of USEPA toxicity criteria for most of these compounds. Additional information should be provided concerning what a MRL is and how it is derived. It is unnecessary to write a toxicological profile for sodium which is an essential nutrient.

      See responses to #28 and #41 for discussion of EMEGs and MRLs. The need for a toxicological profile for sodium or any other substance is determined by an algorithm or by programmatic need. Most essential nutrients can be hazardous under certain exposure circumstances.

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