PROCEEDINGS OF THE EXPERT PANEL WORKSHOP
TO EVALUATE THE PUBLIC HEALTH IMPLICATIONS
FOR THE TREATMENT AND DISPOSAL OF POLYCHLORINATED BIPHENYLS-
CONTAMINATED WASTE

Chapter 5
Key Data Needs

Maureen Y. Lichtveld, M.D., M.P.H.
Allan S. Susten, Ph.D., D.A.B.T.

The expert panel workshop on the public health implications of the treatment and disposal of PCB-contaminated wastes provided ATSDR a special opportunity to convene professionals with diverse knowledge and expertise to address key issues of science and public health. As a result of this workshop, ATSDR identified selected data needs that may form the basis for a future program of research.

The following are key findings and corresponding data needs for each of the three topics discussed at the Expert Panel workshop:

Health Effects

• Finding:

  Assessing the potential health effects from exposure to PCBs, particularly from non-occupational settings, remains difficult.
  Questions about mechanisms of action and dose-response relationships of individual PCB congeners, PCB mixtures, and PCB mixtures with other chemical families (eg., halogenated pesticides, dioxins, and furans) remain to be answered.

  Data Need:

  On the basis on this finding, research is needed to ascertain the toxicity of individual PCB congeners, mixtures of PCBs, and mixtures of PCBs with other chemicals such as dioxins, typically found in combination at hazardous waste sites. Specifically, such efforts should focus on assessing the toxicity of these chemicals with low-level long-term exposures.

• Finding:

  There are increasing concerns about the non-cancer effects of PCBs.
  Until recently, a major focus of health research on PCBs has been on cancer as an adverse health outcome. However, concerns about the potential of PCBs to cause adverse health conditions of immunologic, reproductive, neurologic and endocrine systems are increasing. These concerns have surfaced because results from experimental studies in laboratory animals and from field studies of wildlife, including birds and reptiles, seem to indicate that these noncancer endpoints may be more sensitive indicators of PCB toxicity than is cancer. Furthermore, some recent research findings suggest that neurologic and reproductive changes observed in humans may be associated with environmental exposures to PCBs. Of increasing interest in this regard is the role of the non-dioxin-like (non-coplanar) and less highly chlorinated PCB congeners (4 chlorine atoms or fewer per molecule). Several of these PCB congeners possess estrogenic-like activity, and others are capable of stimulating enzymes in a manner similar to phenobarbital. Only limited data exist, however, on effective doses, the nature of interactions among PCB congeners, and potential for interactions with other complex halogenated compounds. The latter group includes pesticides and pesticide-related compounds (DDT, DDE, aldrin, mirex, etc.) and some of the lower-chlorinated dioxins and furans.

  Data Need:

  In addition to toxicity studies, epidemiologic investigations of communities living near a representative number of hazardous waste sites or releases are indicated. These health outcome studies would evaluate the occurrence of adverse health conditions associated with organ systems most suspected to be affected by exposures to PCBs, such as the reproductive and neurologic systems. By combining sites, study populations are created that are large enough to derive statistically significant findings.

  Incineration

  Finding:

• Few data and studies exist that examine the health effects of incinerators.
  The data gaps that impede an accurate assessment of the public health impact of incineration can be divided into two categories: those associated with the technology itself; and those related to environmental health.

  Data Need:

  Data gaps associated with incineration as a remedial technology in the context of public health, primarily center around inadequate characterization of wastefeeds, emissions, and possible contamination of surrounding environmental media and do not represent research needs per se.

  Key data needs in environmental health related to incineration include these:

  - demographic and health data on the surrounding community.

  - data from exposure, health monitoring, and surveillance activities in communities living near operating incinerator facilities.

  - information about adverse health effects from specific hazardous substances.

  - toxicologic data on the mixtures of substances released from incinerators.

As indicated previously, comprehensive epidemiological studies, including concurrent biological and environmental monitoring in communities living near a representative sample of incinerators are needed to enhance our knowledge about the public health implications of this remedial technology.

Non-Incineration Remedial Technologies

• Finding:

  Because of their early stage of development, data about the public health implications associated with the treatment and disposal of PCB-contaminated wastes by remedial technologies other than incineration are generally lacking. Most non-incineration technologies associated with the treatment and disposal of PCB-contaminated wastes discussed during the workshop, are in a developmental stage. Therefore, there is a lack of information related to the potential public health impacts of non-incineration remedial technologies. However, on the basis of descriptions of the technologies discussed at the workshop and of those identified by literature searches, it is possible, -as is the case with many other treatment technologies including incineration-, that fugitive emissions might occur, that byproducts of chemical and biological processes are formed, and that waste streams containing high volumes of toxic solvents may be formed. In addition, other issues, such as excavation and transport of wastes, future land use, and the time required for treatment and disposal to be completed, may have an impact on public health. Furthermore, most non-incineration remedial technologies discussed during the expert panel workshop may require pre-treatment as well as ultimate disposal. In some cases, a combination of non-incineration remedial technologies may be necessary to achieve adequate waste treatment and disposal.

  Data Need:

  In light of the current state of knowledge about the disposal of PCB-contaminated wastes by means other than incineration, and increasing community health concerns related to incineration, efforts must be made to assess the effectiveness of non-incineration remedial technologies as viable treatment and disposal methods for PCB-contaminated wastes from a public health standpoint.

  Such studies should specifically evaluate matrix-specific characteristics, air emissions including those occurring during upset conditions, and endproduct contaminants.

• General Finding:

  Currently, no data base exists with information about the performance of existing remedial technologies associated with the treatment and disposal of PCB-contaminated wastes, and the toxicological and adverse health effects associated with those technologies.

  Data Need:

  The three expert panels at the workshop independently identified the need for information repositories or other means to compile data and information about the public health implications associated with different aspects of exposure to PCBs. The development of such a comprehensive database would provide important opportunities for cross-fertilization of the environmental engineering and public health fields. This would allow for greater coordination and collaboration in the design and operation of waste disposal facilities to interdict and, where possible, prevent exposures to hazardous substances at levels of public health concern.

These data needs identify broad areas of research to be considered in addition to the specific recommendations derived by the three expert panels. Those recommendations are presented in chapters 2, 3, and 4 and are highlighted in the executive summary of these proceedings.

Appendix I - Project Description

Bloomington Polychlorinated Biphenyls Project Description

The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agency located in Atlanta, Georgia. It is part of the Public Health Service within the U.S. Department of Health and Human Services. Created by Superfund legislation in 1980, ATSDR's mission is to prevent exposure and adverse human health effects and diminished quality of life associated with exposure to hazardous substances from waste sites, unplanned releases, and other sources of pollution present in the environment.

To carry out its mission, ATSDR conducts a large array of activities in the field of environmental public health. Two key activities that relate to ATSDR's Bloomington Polychlorinated Biphenyls (PCB) Project are ATSDR's public health assessments and health consultations.

Public Health Assessments
The Superfund statute, as amended, directs ATSDR to perform public health assessments of all hazardous waste sites listed, or proposed for listing, on the Environmental Protection Agency's (EPA) National Priorities List within one year of listing; and to respond to petitions from citizens requesting public health assessments. ATSDR's public health assessment evaluates data and information on the release of hazardous substances into the environment to assess any current or future impact on public health, to develop health advisories or other health recommendations, and to identify studies or actions needed to evaluate and mitigate or prevent human health effects.

Health Consultations
The Superfund statute also directs ATSDR to provide consultations to EPA, states, and local officials on health issues relating to toxic substances and hazardous waste sites. In addition, members of the U.S. Congress have requested such assistance from ATSDR in the past.

ATSDR's Bloomington Polychlorinated Biphenyls (PCB) Project
ATSDR's Bloomington PCB Project will entail activities in both aforementioned areas. As part of this project, and in accordance with the Agency's public health assessment mandate, ATSDR will conduct a comprehensive evaluation of six hazardous waste sites containing PCB-contaminated soil located in Monroe County, Indiana, using its public health assessment methodology. A preliminary exposure pathways analysis is currently being developed by the Indiana State Department of Health (ISDH) under a cooperative agreement with ATSDR. The report from ISDH's analysis will be included by ATSDR in the Agency's public health assessment of the six hazardous waste sites.

Because of health concerns expressed by some Bloomington area residents, Senator Richard Lugar and Congressman Frank McCloskey asked ATSDR to address any potential public health implications of incinerating PCB-contaminated soil associated with the six sites. To respond to this request, ATSDR will use its expertise and authority in the health consultation area. Specifically, ATSDR will determine the potential public health implications of incinerating the PCB-contaminated soil associated with the six sites. In addition, ATSDR will identify and evaluate pertinent public health considerations associated with other technically feasible non-incineration remedial technologies. The information developed through these consultation efforts will be included in the final ATSDR public health assessment. The public health assessment document will present the results of the overall ATSDR Bloomington PCB Project.

II. Background

Westinghouse Electric Corporation in Bloomington, Indiana, manufactured electrical capacitors containing PCBs from 1958 to 1977. Capacitors that did not meet specifications were discarded in area landfills and limestone quarries, resulting in more than 650,000 cubic yards of PCB-contaminated materials.

Pursuant to the Consent Decree signed on May 25, 1985, by Westinghouse Electric Corporation, the U.S. EPA, the Indiana Department of Environmental Management, the City of Bloomington, and Monroe County, Westinghouse is required to remove an estimated 650,000 cubic yards of PCB-contaminated soil, sludge, solid waste, and stream sediments from six sites in the Bloomington, Indiana, area. These six sites include four NPL sites--Bennett Stone Quarry, Lemon Lane Landfill, Neal's Landfill, and Neal's Dump--and two non-NPL sites--Anderson Road Landfill and the Winston-Thomas Sewage Treatment Plant.

The first phase of the Consent Decree involves removal and remedial measures to contain the six sites until the extensive excavation of PCB-contaminated materials begins. The second phase of the Consent Decree involves the permitting, construction, and operation of a municipal-solid-waste-fueled, high-temperature incinerator that will incinerate the PCB-contaminated materials excavated from all the Consent Decree sites.

III. Activities Undertaken to Date

Environmental Investigations
During the early 1980s, the U.S. EPA, the Westinghouse Electric Corporation, and the Indiana Department of Environmental Management conducted several environmental investigations. The investigations primarily involved environmental media sampling and monitoring. A publicly available Remedial Investigation/Feasibility Study was not performed.

Health Studies
Several health studies have been performed on Westinghouse workers and populations residing in and around the Bloomington area. A summary of the studies follows; a table listing the studies and indicating the key findings can be found in the Appendix.
Centers for Disease Control and Prevention (CDC) Sludge Users Study
The Bloomington, Indiana, municipal sewage treatment plant has made sewage sludge available to local residents for use as fertilizer since the mid-1960s. Much of this sludge was used in organic gardens by persons who wanted to minimize their exposure to agricultural chemicals. From 1972 through 1976, approximately 500 to 1,000 persons obtained sludge at the plant. In the 1970s, however, Bloomington residents began to suspect that the sludge might be contaminated with PCB waste discharged into the sewage system by the electrical capacitor manufacturing plant.

The factory had been discharging waste contaminated with PCBs into the Bloomington municipal sewage system throughout the 18 years of the plant's operation. Further environmental testing through August 1976 confirmed the presence of PCBs in raw sewage, sewage sludge, sludge-treated soil, and in vegetables grown in treated soil.

Among the toxic materials found in mixed industrial and domestic sewage have been metals, including cadmium, lead, zinc, nickel, copper, molybdenum, and selenium, and chlorinated hydrocarbons and pesticides. With repeated application, these materials may accumulate in soils and have the potential to be absorbed by plants, eventually to reach foodstuffs (Baker et al. 1980).

In 1976, then Mayor Francis X. McCloskey asked the Centers for Disease Control (CDC) to evaluate the health effects of exposure to PCBs in individuals who used the contaminated sludge in their gardens.

PCB levels in vegetable samples were generally much lower than those in the soils in which they were grown. Root crops such as beets and carrots appeared to absorb PCBs from soil more efficiently than leafy vegetables. This apparent difference may have been a result of adherence of PCB-contaminated soil to the exterior surfaces of root vegetables.

CDC investigators found mean serum PCB levels were 71.7 parts per billion (ppb) in the 18 individuals occupationally exposed, 33.6 ppb in 129 members of these workers' families, 17.6 ppb in 91 persons who had obtained sludge from the sewage plant, and 23.8 ppb in 23 persons who were not exposed. Forty-nine percent (45) of the sludge users had fewer than 2 years of exposure to PCBs. The maximum exposure was for 4 years. No chloracne or systemic symptoms of PCB toxicity were noted. Serum levels of gamma-glutamyl transpeptidase (GGTP) increased with PCB concentrations. There were no other correlations found between PCB levels and tests of hepatic or renal function. Plasma triglyceride levels increased with serum PCB concentrations. The investigators stated that these data suggest that PCBs may impair liver function and alter metabolism at exposures insufficient to cause overt symptoms.

PCB Concentrations in Environmental Samples, Bloomington, Indiana, 1976

(Baker, et al. 1980)

National Institute for Occupational Safety and Health (NIOSH) PCB Worker Exposure Study
In 1975, the CDC's National Institute for Occupational Safety and Health (NIOSH) was in the process of identifying capacitor manufacturing facilities that could be used in an industry wide study of PCB exposures in capacitor manufacturing workers.

NIOSH chose the Bloomington Westinghouse plant for study because a concurrent epidemiologic study investigating human exposures to PCB-contaminated sewage sludge provided background data on serum PCB concentrations. Data gathering began in 1977 (Baker et al. 1980).

Serum PCB concentrations were many times greater among workers employed in power capacitor manufacturing than among the general population, even comparing employees never assigned to work in PCB-exposed areas. Workers employed in capacitor manufacturing had 8 to 50 times greater lower-chlorinated PCB serum concentrations than the general population, and 2 to 4 times greater higher-chlorinated PCB serum concentrations than the general population (NIOSH 1991). Statistically significant correlations of symptoms suggestive of mucous membrane and skin irritation, systemic malaise, and altered peripheral sensation were noted with increasing concentrations of serum PCBs. No clinical abnormalities attributable to exposure to PCBs were observed. Serum PCB concentrations were positively and significantly correlated with glutamic-oxalacetic transaminase (SGOT), GGTP, and plasma triglyceride, and were inversely correlated with plasma high-density lipoprotein cholesterol. The investigators stated that these findings were indicative of PCBs' physiologic effect on the liver, the long-term health significance of which was unknown. Concerns were raised regarding the long-term cardiovascular effects of exposure to PCBs evidenced by the association of PCBs with plasma triglyceride and the negative association with plasma HDL cholesterol (Smith et al. 1982).

Exposure Study of Residents Living Near Three Hazardous Waste Sites
In late 1983, the Indiana State Department of Health (ISDH) asked CDC for assistance in studying exposure to PCBs among residents living near three waste sites (Lemon Lane Landfill, Neal's Landfill, and Bennett Stone Quarry) in the Bloomington area. A pilot study was conducted to evaluate persons at high risk of exposure to waste contaminated with PCBs at these sites, to determine if any of the individuals had elevated serum PCBs, and to determine which environmental pathways among those containing PCBs might have contributed most to producing elevated levels of PCBs in human sera. On the basis of the results of a screening survey of 995 individuals who lived in proximity to the three sites, a total of 114 individuals were selected to participate in the full study.

Of the 20 individuals with serum PCB levels greater than 20 ppb (20 ppb is the upperbound 95% confidence interval of the normal distribution), 7 had known occupational exposures, 5 were in the highest-risk group, and 9 were from the randomly selected at-risk group. Individuals included in the highest-risk group were persons who had the greatest exposure, that is, from such high-risk activities as capacitor scavenging, swimming, eating fish, or working on site. The at-risk group consisted of the rest of the study population. Twenty percent of the 61 individuals in the highest-risk group had elevated serum PCB levels; 16.3% of the randomly selected at-risk group had elevated serum PCB levels. No specific environmental pathway, with the exception of occupational exposures and scavenging of capacitor parts, could be identified. One explanation given was that exposures in the community were taking place from a combination of pathways, although they could not be individually implicated. No statistically significant differences between the highest-risk group and either of the two comparison groups (unexposed group and the randomly selected at-risk group) were detected for any of the general specific diagnostic categories elicited from a health effects survey questionnaire or from the clinical chemistries results.

There was, however, a statistically significant dose-response relationship between serum PCB levels and the occurrence of self-reported high blood pressure; this relationship remained statistically significant when the data were controlled for the possible confounding effects of age and smoking. The authors recommended further study of the population to ascertain which exposure pathways were responsible for the increased levels of serum PCBs identified, and recommended a larger epidemiologic study investigating the effect of serum PCBs on measured blood pressure (Stehr, Welty, and Steele 1986; Stehr, Welty, Steele, and Steinberg 1986; Steinberg et al. 1986).

Five individuals who had participated in the 1977 NIOSH study and six individuals who had participated in the CDC sludge users study participated in the study described in the previous paragraphs. Changes in their higher- and lower-chlorinated serum PCB congeners were evaluated by reviewing the results of their serum PCB assays conducted in the late 1970s and comparing them to the results of their serum PCB levels analyzed in 1984. Assuming no continuing exposure in 1977 and a log-linear relation to serum PCB levels over time, which is consistent with first-order kinetics of PCB metabolism, the half-life for the lower-chlorinated congeners was estimated to be 6 to 7 months. The half-life for the higher-chlorinated congeners was determined to be 33 to 34 months (Steele et al. 1986).

NIOSH Follow-up Worker Study
In May 1984, ISDH requested assistance from NIOSH to follow up workers occupationally exposed to PCBs. These workers had participated in a cross-sectional medical study conducted by NIOSH in 1977. Serum log PCB concentrations were quantified as lower-chlorinated biphenyls and higher-chlorinated biphenyls. Workers were stratified by NIOSH into higher- and lower-exposed groups based on their 1977 serum PCB concentrations. By 1985, the concentration of the lower-chlorinated congeners in the low-exposure PCB group had decreased by an average of 85% of the 1977 values. Serum PCB lower-chlorinated congener concentrations in the high- exposure group had decreased by an average of 90%. By 1985, the level of higher-chlorinated PCB congeners in the low-exposure and high-exposure groups had decreased by 39% and 58%, respectively, of the 1977 values. No clinical abnormalities attributable to exposure to PCBs were observed. Serum PCB concentrations were positively and significantly correlated with triglycerides, cholesterol, total bilirubin, conjugated bilirubin, beta glucuronidase, 5-prime nucleotidase, serum apolipoprotein A1, serum apolipoprotein B, urinary creatinine, and urinary alanine aminopeptidase. When the prevalence of symptoms and overt clinical disease were investigated by exposure group, no differences between the groups could be ascertained, except for a positive association with GGTP and a negative association with urinary creatinine. The investigators stated that the findings are indicative of PCBs' physiologic effect on lipid metabolism, liver function, and kidney function (NIOSH 1991).

Worker Mortality Study
Also in 1984, ISDH and NIOSH began to evaluate the mortality experience of a cohort of Westinghouse Electric Corporation workers who were occupationally exposed to PCBs. The primary interest was to determine if this cohort had experienced any increased mortality from cancers previously associated with exposure to PCBs. These included malignant melanoma, liver and biliary tract cancer, cancer of the rectum, hematopoietic malignancies, and lung cancer. It was also intended to examine mortality as a function of job-specific exposures to PCBs and to control for other known exposures in the workplace. The cohort comprised 3,588 persons who had ever worked at the Westinghouse facility during the time in which PCBs were used. Although overall mortality and deaths from all cancers combined were less than expected (that is, the healthy worker effect), this study indicated that there was a moderate, although not statistically significant, increase in the risk of dying from cancer of the brain, and a statistically significant increase in deaths from malignant melanoma, a form of skin cancer. These findings applied to all individuals who were employed at the facility from January 1, 1957, through March 31, 1977. The study provides some evidence of an association between PCB exposure in an occupational environment and mortality from malignant melanoma. The brain cancer finding suggests that this outcome should be carefully observed in further follow up of this cohort, which is currently underway (NIOSH 1991).

To elaborate on these findings, the NIOSH investigators used a proportional hazards model to examine the association between cumulative PCB exposure and site-specific cancer mortality. All-cause mortality and total cancer mortality were lower than expected. More deaths were observed than expected for malignant melanoma and cancers of the brain and nervous system. The average estimated cumulative dose for the workers with cases of brain cancer was greater than for other workers, but the 95% confidence intervals around this difference were broad. The risk of malignant melanoma was not related to cumulative PCB exposure (Sinks et al. 1991).

Domestic Animals as Sentinels Surveillance Study
In 1986, ISDH, along with CDC, decided to evaluate the potential for using domestic animals in the surveillance of environmental exposures. Dog owners who lived near the three major PCB waste sites were identified. Each dog owner was identified to obtain information on their dog's age, sex, breed, length of residence in the area, weight, height at the shoulder, confinement (indoors, yard, or leash), and activities outdoors (retrieving and digging). Whenever possible, older dogs that had lived in the area before the 1983 remedial actions limited access to the waste sites and dogs that had been allowed to run free frequently were selected. After selecting nine dogs from Monroe County, a similar questionnaire was used to identify nine comparison dogs owned by CDC employees in Atlanta. Dogs were selected that were similar in weight, height, and age to the Monroe County dogs. The results of the study indicated that the median canine serum PCB level in contaminated areas was 2.96 ppb; the median canine serum PCB level in uncontaminated areas was 1.45 ppb. The findings suggested that pet dogs may serve as sentinels of human exposure to PCBs (Schilling et al. 1988).

ISDH/ATSDR PCBs Exposure Study
In 1987, ISDH requested assistance from ATSDR in evaluating the health implications of exposures to PCBs. This study was a follow-up study to the study conducted by CDC and ISDH staff in 1983 and 1984. The goals of the study were these: (1) ascertain if the population in Monroe County from 18 through 65 years of age with serum PCB levels greater than 20 ppb was similar to what was observed in other cross-sectional studies of populations putatively exposed; (2) evaluate whether there was an association between PCBs and hypertension, and if so, evaluate the strength and nature of the relationship; (3) evaluate the potential for PCBs to induce microsomal enzymes; and (4) identify the exposure pathways that lead to elevated serum concentrations.

The mean total PCB level was 8.1 ppb for males and 7.8 ppb for females. Approximately 3.6% of the study population had serum PCB levels greater than 20 ppb. The range for all study participants was from approximately 1 to 76 ppb. There were statistically significant trends, in the univariate analyses, between increasing systolic and diastolic blood pressures and PCB levels. After adjustment for other variables in the multivariate regression analysis models, PCB exposure was not associated with either diastolic or systolic blood pressure. There was no association between high-density or low-density cholesterol levels and PCB levels. No statistically significant differences among the liver function enzymes were found with serum PCB levels greater than 20 ppb. No statistically significant associations between PCBs and sex, race, educational level, employment status, dietary consumption of game and vegetation, or recreational activities were identified. Eating home-grown vegetables was the only variable associated (although not significantly) with increased concentrations of serum PCBs. The results of this study indicated that, in spite of the potential for exposure to PCB-contaminated media, individuals living in the general community were generally not at risk for PCB exposure, based on the results of their serum PCB levels (Steele and Richter 1992).

IV. Purposes of the Project

Because of health concerns expressed by some Bloomington area residents, Senator Richard Lugar and Congressman Frank McCloskey asked ATSDR to address any potential public health implications of incinerating PCB-contaminated soil associated with these sites. Appropriations to address this concern were approved in H.R. 5679, Amendment No. 195, which provided an additional $250,000 in fiscal year 1993 funds for a PCB exposure study in Monroe County, Indiana. ATSDR has developed the Bloomington PCB Project using these funds.

The purposes of the ATSDR Bloomington PCB Project are these:

1)	to conduct a comprehensive public health assessment of six hazardous waste sites containing PCB-contaminated soil located in Monroe County, Indiana;
2)	to determine any potential public health implications of incinerating the PCB-contaminated soil associated with those sites; and
3)	to identify and evaluate pertinent public health considerations associated with other technically feasible non-incineration remedial technologies.
The tasks of the project are these:
1)	development of a preliminary evaluation of all past, present, and future human exposure pathways, available health outcome data, and community health concerns associated with the six previously named sites. This evaluation is being conducted by the Indiana State Board of Health under a cooperative agreement with ATSDR;
2)	a comprehensive review of past PCB-related health studies;
3)	an evaluation of the public health implications of incinerating the PCB-contaminated waste; and
4)	an evaluation of the public health considerations of other technically feasible non-incineration remedial technologies;
Three expert panels comprising national experts will assist in the conduct of tasks 2, 3, and 4. The findings of the project will be presented in ATSDR's final public health assessment. The final public health assessment will include data developed in the preliminary pathways analysis report and the report from the expert panels. Community involvement is an integral part of the ATSDR Bloomington PCB Project. ATSDR is committed to working closely with the Bloomington community and other federal, state, and local agencies throughout the duration of the project. ATSDR anticipates that the final public health assessment will be available during the summer of 1994.

References

1. Baker E, et al. 1980. Metabolic consequences of exposure to polychlorinated biphenyls in sewage sludge. Am J Epidemiol 112:553-563.

2. Smith AB, J Schloemer, LK Lowry, AW Smallwood, RN Ligo, S Tanaka, W Stringer, M Jones, R Hervin, and CJ Glueck. 1982. Metabolic and health consequences of occupational exposure to polychlorinated biphenyls. Br J Ind Med 39:361-369.

3. Stehr PA, E Welty, and GK Steele. 1986. A pilot study of serum polychlorinated biphenyl levels in persons at high risk of exposure in residential and occupational environments. Arch Environ Health 41:240-244.

4. Stehr P, E Welty, GK Steele, and K Steinberg. 1986. Evaluation of potential health effects associated with serum polychlorinated biphenyl levels. Environ Health Perspect 70:255-259.

5. Steinberg KK, LWJ Freni-Titulaer, TN Roberts, VW Bruse, PW Mueller, PW Stehr, GK Steele, and DT Miller. 1986. Effects of polychlorinated biphenyls and lipemia on serum analytes. J Toxicol Environ Health 19:369.

6. National Institute for Occupational Safety and Health (NIOSH) and Indiana State Board of Health. January 1991. Westinghouse Electric Corporation Health Hazard Evaluation. HETA 89-116-2094.

7. Sinks T, GK Steele, AB Smith, K Watkins, and RA Shults. 1992. Mortality among workers exposed to polychlorinated biphenyls. Am J Epidemiol 36:289-398.

8. Schilling RJ, GK Steele, AE Harris, JF Donahue, and RT Ing. 1988. Canine serum levels of polychlorinated biphenyls (PCBs): A pilot study to evaluate the use of animal sentinels in environmental health. Arch Environ Health 543:218-221.

9. Agency for Toxic Substances and Disease Registry. 1992. Final report: Community exposure to polychlorinated biphenyls, Bloomington, Indiana. Atlanta: Agency for Toxic Substances and Disease Registry.

Studies on Westinghouse Workers and Populations in the Bloomington, Indiana, Area

Appendix II - Workshop Agenda

AGENCY FOR TOXIC SUBSTANCES AND DISEASE REGISTRY

EXPERT PANEL WORKSHOP TO EVALUATE THE PUBLIC HEALTH IMPLICATIONS OF
HUMAN EXPOSURE TO POLYCHLORINATED BIPHENYLS (PCBs)

Indiana Memorial Union, Indiana University
Bloomington, Indiana
September 13-14, 1993

AGENDA

PANEL SESSIONS - MONDAY, SEPTEMBER 13, 1993

PANEL SESSIONS - TUESDAY, SEPTEMBER 14, 1993

Appendix III - Videotape Index

Appendix III

Panel Workshop Videotape Repositories

The sessions of the three workshop panels ran concurrently and were recorded on videotapes. The plenary and summary sessions were also videotaped. Each session was open to the public and ended with questions and comments from the audience. A complete set of videotapes is available for review at the Monroe County Public Library, 303 East Kirkwood Avenue, (812)339-2271.

Also, the videotapes will be available to the public for purchase through the National Technical Information Service in five separate packages: 1) Plenary and Summary Sessions; 2) Health Panel Sessions; 3) Incineration Panel Sessions; 4) Non-Incineration Remedial Technologies Panel Sessions; and 5) a Complete Set of Videotapes. Contact the ATSDR Bloomington PCB Project Office at 1-800-722-8904 for information on how to order these tapes.

Outline of Information Covered in Videotapes

Videotape Package 1 - Plenary and Summary Sessions

Videotape Package 2 - Health Panel Sessions

Videotape Package 3 - Incineration Panel Sessions

Videotape Package 4 - Non-Incineration Remedial Technologies Panel Sessions

Date	Session Title	Topics Discussed
Monday, September 13, 1993	1. Remediation Technologies and Bioremediation	Panel Objectives Remediation Technologies (applications, limitations, including potential releases) Bioremediation
	2. Chemical Dechlorination	Chemical Dechlorination
	3. Soil Washing	Soil Washing
	4. Solvent Extraction	Solvent Extraction
	5. Thermal Desorption	Thermal Desorption
	6. Solidification Stabilization	Solidification and Stabilization
	7. Landfilling	Landfilling Other Issues

Appendix IV - Response to Comments Received

ATSDR received a number of comments. Commenters included the Bloomington, IN, community; consultants; industry; and other federal agencies. Several sets of comments were received that addressed both the Proceedings of the Expert Panel Workshop To Evaluate the Public Health Implications of the Treatment and Disposal of Polychlorinated Biphenyls-Contaminated Waste and the Public Health Assessment for Bloomington PCB Sites (PHA). This appendix will summarize and address the comments on the Proceedings of the Expert Panel Workshop to Evaluate the Public Health Implications of the Treatment and Disposal of Polychlorinated Biphenyls-Contaminated Waste (hereafter referred to as the panel report). Comments that were specific to the PCB sites in Monroe and Owen counties in Indiana will be summarized and addressed as part of the Public Health Assessments for Bloomington PCB Sites.

GENERAL COMMENTS

1. Comment: Several comments suggest modifying the panel reports by adding or deleting information.

   Response: The individual panel reports (Chapters 2-4) reflect the discussions that occurred during the workshop and were reviewed by each panel member at least twice. Chapters 2-4 were not intended to be an exhaustive compilation of all available scientific information but rather an accurate summary of what was discussed. No changes have been made to Chapters 2-4. However, as a result of some comments regarding Chapters 2-4, changes have been made to the executive summary.

2. Comment: The proceedings should be placed in the context of the findings of the EPA dioxin report.

   Response: The purpose of convening the expert panel workshop was to bring experts together to evaluate the most recent toxicity and health data regarding PCBs and remedial technologies that can be utilized to remediate PCB-contaminated wastes. Dioxin contamination may exist at some PCB sites, and the issues regarding dioxin were discussed by the Health Effects Panel. However, dioxin was not a major focus of the workshop. The proceedings are a summary report of the expert panel discussions regarding PCB issues that occurred in September 1993, one year before EPA released its draft dioxin report for public comment. ATSDR does not believe that it is appropriate to make changes to the proceedings based on a document that was released after the panel discussions occurred.

3. Comment: The proceedings concentrate too much on incineration; more emphasis should be given to the Health Effects Panel Report and the Non-Incineration Panel Report.

   Response: As noted previously, Chapters 2-4 reflect the discussions and recommendations of the panels. No attempt was made by ATSDR to provide focus or emphasis on any panel.

4. Comment: The Executive Summary should address the environmental justice implications of the panels' findings and conclusions. For instance, since African-American men experience a higher incidence of cancer than non-African-American men, is their cumulative risk in the face of PCB exposure greater than that for non-African-American men?

   Response: The Executive Summary is a summary of the deliberations of the three expert panels. The panels did not focus or address to any extent environmental justice issues. The intent of all of the panel discussions was to identify what was known about the health effects related to human exposures to PCBs, health effects associated with incinerating PCBs or wastes containing PCBs, and public health implications of using technically feasible non-incineration technologies for the treatment and disposal of PCB-contaminated wastes. However, the two illustrative questions raised by the commenter are worthy of consideration by other programs within ATSDR and by other agencies involved in the environmental health area.

5. Comment: Studies should be conducted to assess the effects of PCBs on reproduction in women and men.

   Response: ATSDR agrees with this comment. The majority of occupational cohorts consist of men. Therefore, there may be an opportunity for research on reproductive effects in both men and women exposed to PCBs as well as for developmental studies among their offspring. The commenter's suggestion would be consistent with Health Effects Panel recommendations D and E (pages 2-32) and ATSDR's conclusion A5 (page xvi). ATSDR will modify the Executive Summary A1 recommendation accordingly. In addition, NIOSH is developing a study to examine whether exposure to PCBs is associated with an increased risk of breast cancer. The study will include women from all capacitor manufacturers previously studied by NIOSH and is separate from the PCB mortality study currently underway.

6. Comment: The Executive Summary contains a litany of recommendations for further studies and research. Can such costly endeavors be justified for a chemical which is no longer in production? If these studies cause delays in the cleanup of sites contaminated with PCBs, what are the impacts those delays will have on public health and the environment? How does it compare to the potential benefit of the information from such studies? We have a lot of data now on incineration: it has the ability to process feed stocks with a wide range of properties and is more flexible than many alternate technologies.

   Response: Even after all the Superfund sites that contain PCBs are cleaned up, the public will continue to have PCBs in their bodies from past exposures. The health studies recommended by the Health Effects Panel will help public health agencies know what the potential long- and short-term health effects of exposure to PCBs may be. The health studies should not delay the cleanup of Superfund sites. Most of the Incineration Panel's recommendations are based on conservative assumptions when evaluating the potential public health impacts of incinerators, monitoring stack and fugitive emissions, and sampling environmental media during the incinerator's operating life. Only one recommendation made by the Incineration Panel could delay a site cleanup: pilot-scale (or full scale) testing of the waste feed is needed if the feed was "unique and there are no previous data on incineration of this waste feed." (See the Comments on Chapter 3, comment #9, for further discussion of this recommendation.)

7. Comment: The recommendations in the Executive Summary should be re-ordered to list first the actions that can be implemented now.

   Response: ATSDR staff reviewed the recommendations section of the Executive Summary and concluded that the recommendations in subsections "A. Health Effects" and "C. Non-Incineration Remedial Technologies" already listed first those actions that can be implemented now. The recommendations in subsection "B. Incineration" were arranged to address this comment.

8. Comment: While federal agencies, academia, and some stakeholders were well represented on the panels, industry and the environmental justice community were not.

   Response: As previously noted, the panels focused on issues of science and technology as these relate to human health. Panel members were invited because of their expertise and experience in areas of PCB remediation and health effects associated with exposure to PCBs. Individuals representing industry or private consulting firms that may sometimes represent industry were present on all three panels. No attempt was made by ATSDR to include or exclude members of the "environmental justice community."

9. Comment: Because EPA does most of the environmental sampling at hazardous waste sites, add "EPA" after "....have been found" on page 1-1, in the second paragraph.

   Response: The paragraph was primarily of an introductory nature and was not meant to be specific. The organization responsible for conducting environmental sampling was not part of the discussions at the workshop. In addition to EPA, state environmental agencies, potentially responsible parties for Superfund sites, and owners of waste handling facilities also conduct environmental sampling. No change in the wording is necessary.

10. Comment: The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) does not specify "hazardous waste sites" as stated in the paragraph 1, line 7, on page 1-2.

    Response: The commenter is correct; the specific language indicates that consultations be prepared "....on health issues relating to hazardous or toxic substances,...." However, CERCLA (also known as Superfund) is concerned with facilities or sites that may represent sources of pollution. ATSDR's intent was to paraphrase the letter and spirit of the legislation. No change is necessary in the panel report.

COMMENTS ON CHAPTER 2 - Expert Panel Report Health Effects Panel

1. Comment: A discussion of the linkage between health effects and exposure (or dose) was absent from the proceedings of the Health Effects Panel discussions. It would be helpful to add some graphics demonstrating threshold dosage ranges, ambient exposures, and estimates of local and national releases of PCBs.

   Response: The set of questions utilized to stimulate scientific discussions and interchange among panel members at the workshop had an emphasis on known and perceived health effects. The direction and content of the discussions emphasized issues associated with outcomes more so than exposures. In preparation for the expert panel workshop, ATSDR conducted comprehensive literature reviews of all previously conducted epidemiologic studies associated with PCBs. Key studies including some that focused on exposure are included in the project description (See Appendix I).

2. Comment: There appears to be a constant equating of exposure to dose in the Health Effects Panel report. There should be a discussion of factors affecting the bioavailability (internal dose) after dermal or inhalation exposures.

   Response: ATSDR concurs that exposure should not be equated with internal dose to target organs. Many factors affect the bioavailability of PCBs after dermal or inhalation exposures. Because this information was not presented or discussed in detail by the Health Effects Panel, it is not appropriate to modify the Health Effects Panel Report. However, ATSDR recognizes that this is pertinent information. The ATSDR Toxicological Profile for PCBs contains this type of information (page 2-34).

3. Comment: Several identified sentences on page 2-15 are unclear--is cancer incidence or cancer mortality being discussed?

   Response: The sentences identified pertain to cancer mortality.

4. Comment: What is the impact of the healthy worker effect on PCB-associated cancer incidence?

   Response: The Health Effects Panel evaluated this issue. It was unclear to the panel if or how the healthy worker effect might affect the magnitude of any risk estimates for PCB-associated cancer.

5. Comment: On page 2-17 in the third paragraph, does "they" refer to "levels of PCBs" or "signs or symptoms?" The proceedings should note and address environmental justice issues.

   Response: "They" refers to "signs or symptoms." As indicated earlier, the workshop, including the Health Effects Panel, did not specifically address or exclude environmental justice issues.

6. Comment: Several technical or interpretive questions were received pertaining to the cited literature related to the statistical power of standard deviations reported in studies cited.

   Response: This report provides a synopsis of what was presented or discussed by panel members. The issues described in this comment were not deliberated by the Health Effects Panel. Specific references for cited literature are provided in this chapter for further investigation.

7. Comment: Include a discussion of what animal species are sensitive for all endpoints.

   Response: This information was not discussed by the panel members and is beyond the scope of the Health Effects Panel Report. However, the ATSDR Toxicological Profile for PCBs contains this information (page 2-34). Copies of the profile are available from ATSDR, Division of Toxicology, 1600 Clifton Road, M/S E-29, Atlanta, GA 30333.

8. Comment: Discuss the bioavailability of PCBs after dermal exposure and the resulting systemic health effects.

   Response: The Health Effects Panel did not discuss bioavailability. In human studies, much of the information regarding health effects of PCBs is obtained from occupational exposures where relative contributions of inhalation and dermal routes are unclear. In animals, the adverse effects include centrilobular degeneration of the liver, tubular degeneration of the kidney, acne and hyperkeratosis of the skin, and thymic atrophy (Vos JG, Beems RB, 1971. Dermal toxicity studies of technical polychlorinated biphenyls and fractions thereof in rabbits. Toxicol Appl Pharmacol 19:617-633). When evaluating the relevance of animal studies to humans, factors to consider include the vehicle used, the surface area exposed, and the duration of exposure.

9. Comment: Do the health effects from remediation technologies differ among the exposed poor and minority groups compared to other subgroups of the general population?

   Response: The lack of information about waste feeds, the efficiencies of various remediation technologies, and potential emissions from different technologies precluded any discussion by the Health Effects Panel of exposure doses and specific health effects from different remediation technologies. Therefore, based on the deliberations of the Health Effects Panel, conclusions cannot be made concerning possible differences in health risks between poor and minority groups compared to other population subgroups.

10. Comment: The recommendations did not address environmental justice concerns and the need for research to answer environmental justice questions related to PCB exposures.

    Response: As indicated earlier, this panel primarily focused on PCB-associated health issues facing the total general population and did not specifically address environmental justice issues. See responses to General Comments #4 and #8 and Comment #5 in this section.

COMMENTS ON CHAPTER 3 - Expert Panel Report PCB Incineration Panel

1. Comment: What was the purpose of the Incineration Panel's discussions? The panelist did not seem well-informed about Monroe County and the City of Bloomington's unique problems.

   Response: The panel discussions were not meant to be site specific. The purpose of the incineration panel was to discuss the use of incineration as a remedial technology for the disposal of wastes contaminated primarily with PCBs. From a generic viewpoint, the panel discussed the data that are available on stack emissions, residuals, effectiveness of various types of equipment, operating conditions, and other factors that affect emissions, data gaps in knowledge incineration, and potential pathways of public exposure from incineration facilities.

   The Incineration Panel was not briefed on the proposed Bloomington incineration facility or any other incineration site at which ATSDR is involved. ATSDR will use the information provided by the panel to address the Bloomington site-specific issues and issues related to incineration in other communities around the country.

2. Comment: The Incineration Panel was not a well-balanced panel. In particular, there were more "pro-incineration experts" on the panel than "anti-incineration experts."

   Response: ATSDR's purpose in selecting the various panel members was to gather the broadest range of expert views, not to make policy decisions where the number of people with a particular view or consensus would be important. No consensus was sought, and each panel member was given opportunities to express opinions and provide factual information in support of opinions. As discussed on page 1-3, because ATSDR viewed these panels as critical sources of information, concepts, and recommendations applicable to hazardous waste disposal nationwide, every effort was made to select panel members with demonstrated expertise and diverse viewpoints and professional affiliations. The criteria set for selecting panel members included relevant expertise in a discipline appropriate for one of the panels, articles published in peer-reviewed scientific journals or in technical journals, and direct knowledge and experience with PCBs or similarly complex organochlorine substances such as dioxins and furans. In addition, for the Incinerator and Non-Incineration Remedial Technologies panels, an attempt was made to identify individuals who, along with their technical and engineering expertise, also had demonstrated knowledge or experience dealing with issues of public health. Identification of the panel members was through literature searches and acquisition and review of technical reports written by potential panel members, and by contacting academic institutions; private organizations; local, state, and federal government agencies; national and local environmental interest groups; and national professional societies. To ensure that all viewpoints were expressed, no consensus on issues was required.

   Using these criteria, ATSDR selected the Incineration Panel members with the following backgrounds and affiliations: two environmental activists who are recognized for their incineration expertise, two academicians, two EPA employees (one expert in incineration and the other an expert in risk assessment of incinerators), a representative from a national laboratory who has published extensively on the public health effects of various types of incineration, a consultant who has conducted risk assessment for combustion facilities for several government agencies, a consulting engineer involved in several EPA incineration studies, a representative from the Centers for Disease Control and Prevention, and an ATSDR representative familiar with incineration issues to coordinate the panel's activities.

3. Comment: Does ATSDR believe that we should try to prevent and not add to the high levels of persistent toxic chemicals and heavy metals in background pollution?

   Response: Yes, ATSDR does believe that we should try to limit or prevent exposure to all toxic chemicals under circumstances that would lead to adverse human health effects. ATSDR's mission is "to prevent exposure and adverse human health effects and diminished quality of life associated with exposure to hazardous substances from waste sites, unplanned releases, and other sources of pollution present in the environment." As stated by Barry L. Johnson, Ph.D., Assistant Surgeon General and Assistant Administrator of ATSDR, in his testimony on January 24, 1994, before the Subcommittee on Human Resources and Intergovernmental Relations, United States House of Representatives, "Incineration of wastes should be viewed from a public health perspective in the larger context of generation and management of wastes. Wastes become a public health concern when they are improperly managed and disposed of. Therefore, in a public health context, the most protective action is not to produce waste. Waste elimination or minimization comports with prevention or reduction of health consequences of wastes."

4. Comment: The best way to prevent dioxins from entering the environment would be to prevent incinerators from being built. For those in operation, the best available pollution control technology should be required for storage of incinerator ash, particularly fly ash, but also bottom ash if it contains significant amounts of dioxins.

   Response: The best way to prevent dioxins from entering the environment is to minimize the creation of or not to produce hazardous wastes and to recycle or reuse any wastes if possible by means that do not cause the generation of dioxins. Incinerators are only one source of dioxin in the environment; other sources of dioxin include cigarettes, fireplaces, automobiles, coal burning power plants, and industrial plants. The newer incinerators are designed to minimize emissions; therefore, replacing old incinerators with state-of-the-art incineration facilities or requiring the old incinerators to be upgraded to have the best available pollution control technology would be desirable. ATSDR concurs that incinerator ash containing significant amounts of dioxin should be managed in a manner that prevents human exposure.

5. Comment: How significant is the use of escape valves of incinerators and the malfunction provision in EPA's regulations to the public health in terms of kinds and quantities of emissions?

   Response: The Incineration Panel pointed out that there are insufficient data at this time on the emissions from escape valves, also known as thermal relief valves or emergency stacks. The panel recommended that testing of these stacks is needed and that data should be used, when available, to evaluate the public health impacts of the incineration facility. ATSDR evaluates public health impacts on a site-specific basis using available data from a particular facility. Data on changes in the levels of emissions resulting from compliance with EPA's malfunction provision would be necessary to evaluate the public health impacts of the regulation. Such data are not yet available.

6. Comment: On page 3-11, the dates of the tests should have been given.

   Response: The Dow Chemical Company in Louisiana conducted its test in December 1986. The Mobay Chemical testing was conducted in July and August 1988. These dates will be added to the text.

7. Comment: Does ATSDR have fugitive emissions and stack emissions data taken during day-to-day operation, including process upsets or malfunctions, of a hazardous waste incinerator that is burning a complex mixture of chlorinated hydrocarbons and heavy metals in soil?

   Response: No, ATSDR does not have such data. EPA and state environmental agencies and the facility owners are responsible for facility and environmental monitoring. The Incineration Panel identified this type of information as a data gap where more testing is needed.

8. Comment: ATSDR appears to be pro-incineration based on certain statements in the ATSDR document Public Health Overview of Incineration as a Means to Destroy Hazardous Wastes and testimony by Dr. Barry L. Johnson, Assistant Administrator of ATSDR, on January 24, 1994, before the Subcommittee on Human Resources and Intergovernmental Relations, on the health impacts of incineration. Dr. Johnson's testimony on the lack of knowledge of health effects from incineration is sufficient grounds for outlawing incineration of hazardous wastes until the data gaps are filled and the results evaluated.

   Response: Because ATSDR has received so many questions regarding the use of incineration at Superfund sites, the Agency staff developed the guidance document Public Health Overview of Incineration as a Means to Destroy Hazardous Wastes. The guidance document points out the site- specific factors that are important for the health assessor to evaluate before determining on a site-specific basis what the public health implications of an incineration facility are. The document does not suggest that all incinerators are protective of public health; rather, it requires that a number of factors be evaluated before drawing any conclusions. In the guidance document, ATSDR implies that poorly run or operated incineration facilities can impact public health, and that even a properly designed and operated incinerator, if placed in the wrong location, may adversely effect public health.

   Data gaps do exist for incineration as pointed out by the expert Incineration Panel and summarized for Congress by Dr. Johnson in the referenced testimony. However, this does not imply that incineration should be outlawed. Rather, ATSDR considers it important to evaluate each situation on a site-specific basis. To provide data to help fill some of the data gaps regarding the health effects related to combustion facilities, ATSDR is conducting several health studies in communities living near incinerators and other combustion facilities. In addition, ATSDR often requests additional environmental data to help make better public health decisions.

9. Comment: One of the Incineration Panel's recommendations listed in the Executive Summary and Chapter 3 states that pilot or full-scale tests should be run before incineration or "unique" waste feeds. PCB wastes from 100% to dilute aqueous stream and low PCB concentration soils have all been burned at full scale. What other PCB wastes exist that do not fall within the wide ranges of PCB concentration, ash content, chlorine content, and heat value that have already been incinerated?

   Response: The panel was asked to discuss PCB incineration in general, not to review any specific PCB incinerators. However, that discussion included data relevant to using Municipal Solid Waste (MSW) as the primary fuel to co-incinerate sewage treatment sludge, PCB-contaminated soils, MSW, and stream sediments. None of the panel members were aware of this combination of waste feeds. Most, if not all, of the panel members thought this combination was "unique" and should be tested in a pilot-scale facility before construction of a full-scale incinerator. They were doubtful that MSW would provide sufficient heating value to maintain stable operating conditions and sufficiently decontaminate the PCB-contaminated wastes if these wastes were mixed with the MSW and sewage treatment sludge.

10. Comment: On what basis does the Incineration Panel recommend (Executive Summary, page xvii and page 3-40) that fly ash and bottom ash should not be mixed until these wastes are characterized? Both fly ash and bottom ash are residues of the waste fed to the process; why shouldn't these wastes leave the process as one stream?

    Response: The panel members did not preclude mixing of the bottom ash and fly ash AFTER they were initially characterized and the disposal options evaluated. Some panel members suggested that if the fly ash and bottom ash were characterized separately, that sometimes it might be possible to recycle the fly ash due to its metal content; whereas it would not be feasible if it was mixed with the bottom ash. The example was also given that bottom ash could be returned to the site, but that the combined ashes might not pass certain land disposal restrictions.

COMMENTS ON CHAPTER 4 - Expert Panel Report Non-Incineration Remedial Technologies

1. Comment: While the discussion of non-incineration treatment technologies is interesting, it did not reflect the same level of scrutiny with regards to health impacts as did the incineration portion of the proceedings. The noted data gaps appear as afterthoughts. Furthermore, it is important to highlight that fugitive emissions will occur regardless of the technology selected and that these emissions pose the greatest risk to public health. Finally, most of these non-incineration alternatives use off-site incinerators to destroy the residuals from the waste stream. This fact appears to have been overlooked in the discussion of alternatives.

   Response: Unlike incineration, many of the non-incineration technologies reviewed have little, if any, performance history information for treatment of PCBs. Therefore, indepth discussions concerning health effects related to these technologies were not possible. There are limited data available concerning possible emissions associated with use of non-incineration technologies. The panel identified data gaps, where possible, including fugitive emissions, so that future efforts can focus on collecting information on possible releases and public health implications. Indeed, some non-incineration technologies will produce residuals requiring additional treatment or disposal. The report notes that bioremediation, dechlorination, solidification/stabilization would not typically require additional treatment or disposal. Solvent extraction and soil washing concentrate the PCBs and would produce residuals requiring treatment or disposal.

2. Comment: Did the expert panel evaluate warehouse storage or vaulting of PCB-contaminated material?

   Response: The Non-Incineration Remedial Technologies Panel discussed several aboveground disposal options for PCB contaminated wastes, including warehouse storage and vaulting. Additional information on those options is presented on page 4-30 of the document. Warehouse storage is typically used for temporary storage periods of 10-20 years. Vaulting or entombment (typically built from concrete) is used to store material from 50 to more than 100 years. Both options require long-term maintenance and environmental monitoring to ensure continued integrity of the containment systems. Warehouse storage or vaulting require excavation of the wastes and may require pretreatment (i.e., dewatering, removal of debris, etc.).

1. According to HazDat, an interactive personal computer platform for data gathered from more than 1,600 hazardous waste sites for which ATSDR has conducted public health assessments, prepared health consultations, or provided emergency response. It includes data on more than 2,000 hazardous substances found at hazardous waste sites. HazDat can be accessed through Internet using a World-Wide Web browser.

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