of environnental contaminants have high body burdens of toxic chemicals 
and serious pathological conditions (i.e., liver neoplasnns). In addition, 
very recent studies of juvenile Chinook salmon captured in Seattle's 
EXiwamish Waterway have shown that these fish have substantial body burdens 
of contaminants, (The potential effects on the health of these juvenile 
salmon exposed to these toxic chenicals are yet to be assessed.) 
TO date we have successfully employed a multidisciplinary approach to 
investigate pollution and its effects in Puget Sound. Following this 
approach we are further developing sensitive chemical and biological 
indicators of pollution for use in assessing pollution impact in 
estuarine and coastal areas. More investigations of cause-and-effect 
relationships between observed biological effects such as fish diseases 
and environmental contaminants are also being conducted. At present, 
evidence linking fish diseases, such as liver tumors, to specific classes 
of chemicals is based on circumstantial evidence obtained in field studies. 
These investigations should include additional field studies, as well as 
controlled laboratory studies. For example, studies in progress in our 
laboratory involve a series of long-term (1 to 2 year) exposures of 
English sole and rainbow trout to selected fractions of extracts of 
sediments fron contaminated sites in Puget Sound and to selected individual 
compounds known to be carcinogenic in laboratory mammals. Fish are 
periodically sacrificed and examined for histopathological conditions in 
the liver. Information on cause-and-effect relationships betv^en 
biological perturbations and individual chemicals or groups of chemicals 
can help implement source control and/or clean up actions by regulatory 
agencies. 
105 
