declining harvests of Columbia River otter populations (as opposed to upward 

 trends elsewhere in Oregon) suggest that PCRs may be a contributory agent 

 (Henny et al . 1981). 



In little brown bats ( Myotis lucifugus ) and big brown bats ( Eptesicus 

 fuscus ) from Maryland, pups found dead at birth had significantly more Aroclor 

 1260 than live 1 ittermates; moreover, females with elevated Aroclor 1260 

 residues tended to produce litters with a greater frequency of stillbirths 

 (Clark and Lament 1976; Clark and Krynitsky 1978). 



PCBs were recently detected in 13 of 26 Florida manatees ( Trichechus 

 manatus ), an endangered species. All individuals with detectable PCR residues 

 were recovered from locations in the relatively urbanized areas of 

 northeastern Florida, primarily in the lower St. Johns River and Brevard 

 County (O'Shea et al. 1984). 



In harbor seals ( Phoca vitulina ), PCB concentrations decrease with 

 increasing blubber thickness (Van Der Zande and Oe Ruiter 1983). As expected, 

 lower chlorinated PCBs were eliminated more rapidly from blubber lipids than 

 higher chlorinated PCBs. For harbor seals in particular, blubber PCB residues 

 contained a small fraction of lower chlorinated components when compared to 

 PCB residues in fish that they eat (Van Der Zande and De Ruiter 1983). PCBs 

 in adult Weddell seals ( Leptonychotes weddelli ) were predominantly penta- and 

 hexachlorobi phenyls; a si igntly higher amount of lower chlorinated biphenyls 

 were found in newborns (Hidaka et al. 1983), suggesting that lower chlorinated 

 biphenyls are more easily transferred from mother to pup through 

 transplacental action than higher chlorinated biphenyls. Weddell seals 

 contain low concentrations of PCBs in blubber compared to 10 other pinniped 

 species and small cetaceans. This probably reflects the low PCB burdens in 

 their diets attributed, in part, to the heavy ice and snow cover during much 

 of the year that prevents atmospheric deposition of PCBs from entering the 

 water and contaminating their diet (Hidaka et al. 1983). 



INTEGRATED STUDIES 



Biomagnification of PCBs through marine food chains in an Australian 

 estuary became increasingly important with upper level carnivores such as 

 gulls and pelicans, but was relatively unimportant at lower trophic levels 

 (Shaw and Connell 1982). A similar situation was observed in Central Puget 

 Sound in Washington in 1979 (Malins et al. 1980). PCB body burdens in marine 

 organisms, especially benthic organisms, were directly related to the log of 

 PCB concentration in sediments (Shaw and Connell 1982). Furthermore, PCBs 

 were found in every tissue analyzed from fish and invertebrates in Puget Sound 

 in 1979 (Malins et al. 1980). High PCB levels, especially in sediments, have 

 been recorded from highly industral ized areas worldwide (Raldi et al. 1983). 



PCBs used in the manufacture of electrical equipment at two facilities 

 located on the upper Hudson River in Washington County, New York, have 



34 



