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PCBs MIHI SYMPOSIUM ISSUES
Session Ho*
, Session Topic and Issues_______________
Authors
I Analytical Methodologies
Dr. Edo D.
\ Current threshold concentrations for identi- Pelliezari
ficatlon of PCBs in the environment using
various analytical methodologies
'* Current threshold concentration for identifi
cation of polychlorinated dibenzofurans (con
taminants of PCBs)
o Heed, 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
*
Discussants
Dr- Mary S. Wolff
II Exposure Studies-- Environmental Residues and Bioaccumulation A. Environmental Residues
Dr. Brock ,Heely
Dr. Mark Melancon
1. Quantity of PCBs released to environment
per year from "totally enclosed systems"
and other sources
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
Continued-
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PCBs MIMI SYMPOSIUM ISSUES-- continued
Session Ko.
Session Topic and Issues
Authors Discussants
B. ^t.
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
airi 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
-Bioaccumulation
Dr. Mary Jo
1. Bioaccumulation rates of PCBs in fish, wildlife and humans
Vodicnik
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
tence of PCBs in food chain
Discussion period
Dr. Mark Melancon
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
Relative importance of release compared to
existing environmental pools of PCB
Discussion period
IV Health Effects-- Epidemilogy
Dr. William Dr. Renate
Studies of sports-fishermen In Michigan who R. Gaffcy Kimbrough
have consumed high concentrations of PCBs in
contaminated fish
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PCBs MINI SYMPOSIUM ISSUES-- continued
Session No.
Session Topic and Issues
Authors Discussants
O Study on Michigan farmers exposed to PCBs from silos coated with PCBs
O Recent reviews of "Yusho incident" 0 Other incidents involving PCB exposure o Recent studies on PCBs in human tissues o Half-lives of PCBs in humans o Discussion Period
Health Effects-- Laboratory Studies
Dr. Seymour
A. Reproductive Effects
Friess
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
X. Recent studies on mutagenicity of PCBS
O Mutation frequencies
O Statistical significance
0 Proposed mechanisms of action and eval
uation of their appropriateness
o Sensitivity of test method
Dr. Renate Kimbrough
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PCBs MINI SYMPOSIUM ISSUES-- continued
Session Ho.
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 A. Recent studies on ecotoxicity of PCBs in
Dr. Richard Dr. Mark
Hunter
Melancon
various fish and wildlife species
1. Reported effects
2. LDSOs 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
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'CDs MINI SYMPOSIUM ISSUES --continued
ession Ho.
* Session Topic and Issues
Authors
D. Relative sensitivity of mammalians to repro
ductive and lethal effects of PCBs 1. Mink 2 Felines
S. Primates 4. Rodents 5. Others E. Modes and rates of absorption for fish and wildlife
F. Comparison of field concentrations of PCBs and reported effect levels for reproductive and
\ other chronic effects in fish, birds and mammals of economic importance 1. Water, sediment and food chain concentrations
2. Modification of PCBs* toxicity by meta-
holism 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
o Health and environmental implications of
James
current environmental and human tissue
concentrations of PCBs
0 Relationship of environmental and human
tissue concentrations of PCBs to exposure
' O Possible environmental concerns for safety of
Bonochlorinated 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
0 Discussion period
Discussants
t Dr. Roy Harbison
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