exert inhibitory effects on photosynthesis and cell motility. In addition to 

 direct toxic effects on algae, accumulated PCBs are readily introduced into 

 the aquatic food chain (Rohrer et al . 1982). 



Selected species of terrestrial plants collected in upstate New York 

 showed decreases in total PCB concentrations of 42% between 1978 and 1980; 

 however, levels in hay in 1979 varied between 0.08 and 0.10 ppm dry weight, or 

 nearly half the Food and Drug Administration (FOA) limit of 0.2 ppm for PCBs 

 in feeds for livestock (Buckley 1983). Plants grown on soils amended with 

 lake sediments contaminated with Aroclors 1248, 1254, and 1260, accumulated 

 PCBs (Sawhney and Hankin 1984). Uptake of Aroclors by beets ( Beta vulgari s ), 

 turnips ( Brassica rapa ), and beans ( Phaseolus vulgaris ) was in the order 

 1248>1254>1260, indicating that lower chlorinated isomers (which are more 

 soluble in water and more volatile) were more abundant in crop plants than 

 higher chlorinated isomers. Based on these studies, continued monitoring of 

 plants used as forage for livestock and wildlife appears necessary, especially 

 in locations where soils are amended with PCB-contaminanted aquatic sediments 

 or sewage sludges. 



INVERTEBRATES 



Aquatic invertebrates assume an important role in the cycling of PCBs 

 within and between ecosystems. Mysid crustaceans from Lake Michigan appear to 

 have a low assimilation efficiency for PCBs and a high efficiency for fecal 

 excretion of ingested PCBs; fecal pellets sink rapidly (80-170 m/day) and many 

 probably reach the sediments intact before the onset of microbial degradation 

 (Evans et al. 1982). By vertically migrating to the surface at night, mysids 

 may transport PCBs into the upper regions; the PCBs will continue to recycle 

 through the Lake Michigan ecosystem if the PCBs are excreted, egested, lost 

 with molts, or if the mysid is consumed by fish. PCB levels of freshwater 

 oligochaete worms from the Niagara River in New York State were positively 

 correlated with sediment PCB levels (Fox et al. 1983). Uptake of PCBs from 

 the sediment by chironomid ( Chi ronomus plumosus - type) larvae was also 

 directly related to the concentration of PCBs in the sediment (Larsson 1984). 

 When larvae metamorphosed to adults, PCB compounds were concentrated and 

 transferred from the aquatic to the terrestrial environment. In a field study 

 near a Swedish sewage plant outfall, transport of PCBs by chironomids from 

 the aquatic to the terrestrial environment was estimated at 20 ug of PCBs 

 per m^ annually. Terrestrial predators that feed on emerging aquatic insects 

 whose larval stage inhabits PCB-contaminated sediments may be exposed to PCBs 

 (Larsson 1984). 



FISH 



Trace concentrations of the more persistent, more highly chlorinated PCBs 

 are detected in fish from almost every major river in the United States 



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