Document KR11d3Z7ODmEqeV57EwNyn116

CijeSystems,J;tc " PCBs MINI SYMPOSIUM ISSUES Session No. _____________ Session Topic and Issues_______________ Authors Discussants I Analytical Methodologies Dr. Edo D. Dr. Mary S. o Current threshold concentrations for identi- Pellizzari Wolff fication of-PCBs in the environment using various analytical methodologies o Current threshold concentration for identifi cation of polychlorinated dibenzofurans (con taminants of PCBs) o Need, if any, for standarized sampling proce dures to reduce inter-laboratory variability in PCB residue analysis o Identification and measurements of PCBs formed in process streams o Discussion period II Exposure Studies-- Environmental Dr. Brock Dr. Mark Residues and Bioaccumulation Neely Melaacon A.* Environmental Residues 1. Quantity of PCBs released to environment per year from "totally enclosed systems" and other sources f 2. Quantity of PCBs released from leaking .condensors and transformers 3. Quantity of PCBs released through disposal processes o Efficiency of high temperature PCB disposal o Efficiency of PCB disposal in indus trial boilers and impact of disposal in wider areas 4. Dispersal pathways of PCB following envi ronmental release . o Effect of release concentrations of PCBs in Great Lakes, in other open "PCB hot spots" for next 10, 20, 30 years o Impact of anticipated release on PCB concentrations in edible fish from these waters 5. Populations specifically exposed and exposure trends o Recent data concerning concentrations and stability of PCBs in various eco logical environments, and the decay half-lives of these systems continuedN&V Q3bd83 JCifeSystems,he. PCBs MINI SYMPOSIUM ISSUES-- coatinued Session No* | ^ Session Topic and Issues __________ Authors Discussants o Background levels of PCBs in the at mospheric , terrestrial and aquatic com partments of the environment o Average residence times for PCBs in the three environmental compartments or, conversely, the degradation rates in air, water and soil o Assuming no further release of PCBs, anticipated decay rate in food supplies, background levels and human tissue. 6. Comparison of expected field levels of PCBs to effect levels in mammals 7. Probability of PCB transformer/condensor fires forming TCVDs and PCDFs; impact of seed fires B. Bioaccumulation 1* Bioaccumulation rates of PCBs in fish, wildlife and humans Dr. Mary Jo Dr. Mark Vodicnik Melancoa 2. Excretion rates of PCBs in fish, wild life and humans 3. Impact of PCB bioaccumulation in plants 4* General description of biotransformation patterns 5. Likelihood of acute lethality resulting from food chain accumulation of PCBs in aquatic environment 6. Likelihood of acute lethality resulting from food chain accumulation of PCBs in terrestrial animals 7* Recent data on bioaccumulation and persis- tance of PCBs in food chain C. Discussion period III Exposure Studies-- Industrial Processes Dr. Kent Dr. Robert o Estimation of PCBs incidentally formed in Hodges Kaley various process streams o Worker exposure streams o Potential for environmental release o Relative importance of release compared to existing environmental pools of PCB o Discussion period . IV Health Effects-- Epidemilogy o Studies of sports-fishermen in Michigan who have consumed high concentrations of PCBs in contaminated fish Dr. William Dr. Renate R. Gaffcy Kimbrough , 2 continuedNEV 036884 CifeSystemsJnc. PCBs MINI SYMPOSIUM ISSUES-- continued Session No. . _____________ Session Topic and Issues __________ o Study on Michigan farmers exposed to PCBs from silos coated with PCBs o Recent reviews of "Yusho incident" o Other incidents involving PCB exposure o Recent studies on PCBs in human tissues o Half-lives of PCBs in humans o Discussion Period Authors Discussants V Health Effects-- Laboratory Studies Dr. Seymour Dr. Renate A. Reproductive Effects . Friess Kimbrough 1. Relevance of studies on reproductive Dr. Stephen effects in Rhesus monkeys (Allent et al.) Safe for humans 2. Other recent studies demonstrating repor- ductive effects o Dosage levels o Species o Types of abnormalities o Incidence o Types of abnormalities o Incidence o Severity o Number of effect levels o Significance levels for parameters 3. Significance of animal reproductive studies and conclusions about potential effects of PCBs on human reproduction B. Carcinogencity 1. Recent studies on carcinogenicity of PCBs o Dose-response relationships over time * o Statistical significance 2. Consensus of scientific opinion on carcin ogenicity of PCBs in animals and humans o PCBs as "initiators" or "promoters" o Mode of action for reported carcino genic effect (and specifically arene oxide formation) 3. Significance of animal studies to human 'population C. Mutagenic Effects 1. Recent studies on mutagenicity of PCBs o Mutation frequencies o Statistical significance o Proposed mechanisms of action and eval uation of their appropriateness o Sensitivity of test method continued- 3 NEV 036885 JCifeSystemsJuc. PCBs MINI SYMPOSIUM ISSUES-- continued Session No. ______________ Session Topic and Issues____ '__________ Authors 2. Conclusions o Mutagenic potential of PCBs o Significance of animal data to human population D. Other Health Effects 1. Placental transfer rates 2. Rate of entrance of PCBs into human breast 3. Potential target organs in humans o Neuroendocrine effects on thyroid, adrenals, gonads and hypothalamicpituitary axis hepatotoxicity o Others 4. Dermal and inhalation absorption rates in humans 5. Significance- of observed persistent chloracne and skin pigmentation changes 6 . ' Relevance for humans of studies by Allen et al. in demonstrating learning disabili ties in Rhesus monkeys and low PCB dosages 7. Evidence of detrimental effects on learn ing in species other than monkeys 8. Other health effects observed for PCBs o Effect o Species o Dose o Statistical significance E. Discussion period Discussants * VI Environmental Effects Dr. Richard Dr. Mark A. Recent studies on ecotoxicity of PCBs in Hunter Melancon various fish and wildlife species 1. Reported effects 2. ID50s 3. Statistical significance B. Impact of impaired reproduction on phyto plankton, daphnid and fish populations 1. Potential for population changes 2. Potential for community disruption C. Reproductive impairment in exposed birds .. 1. Residues in bird eggs 2. Behavioral alterations 3. Relative contributions to impaired repro duction Continued- NEV 036686 4 PCBs MINI SYMPOSIUM ISSUES-- continued Session Mo* ,,____________ Session Topic and Issues __________ Authors Discussants D. Relative sensitivity of mammalians to repro ductive and lethal effects of PCBs 1. Mink 2. Felines 3. Primates A . Rodents 5. Others E. Modes and rates of absorption for fish and wildlife F. Comparison of field concentrations of PCBs and reportedeffect levels for reproductive and other chronic effects in fish, birds and mammals of economic importance 1, Water, sediment and food chain concentra tions 2. Modification of PCBsr toxicity by meta bolism in mammals or fish G. Significance of mutagenic effects studies in animals on fish and wildlife population H. Significance of carcinogenic effects studies in animals on fish and wildlife population I. Discussion period / VII Risk Assessment Dr. Robert Dr. Roy o Health and environmental implications of James Harbison current environmental and human tissue concentrations of PCBs o Relationship of environmental and human tissue concentrations of PCBs to exposure o Possible environmental concerns for safety of monochlorinated biphenyls and other low chlorinated isomers o Impact of analytical uncertainties for PCB residue analyses on risk assessments o Potential synergistic activity of PCBs with other chemical groups, and estimates of numbers of chemicals in each group for which synergism may exist o Concern for increased susceptibility to disease in populations of animals after PCB exposure o Discussion period NEV 036807 5