in a significant reduction in the body burden of persistent PCBs such as 

 2,5,2' ,5'-tetrachloro BP (Vodicnik and Peterson 1985). The percent lipid, and 

 the percent of total lipid deposited in their eggs, markedly influences PCB 

 transfer from fish to eggs (Niimi 1983). Mean percent PCB residue levels 

 translocated to eggs in five species of Great Lakes fish varied from a low of 

 5.4 in rainbow trout to a high of 29.3 in yellow perch, and these (and 

 intermediate) percentages reflected lipid percent levels transferred (Niimi 

 1983). Structural features in PCB forms and congeners cause different 

 elimination rates between individual components in fish, resulting in 

 differences in PCB composition between tissues and the source of uptake (Boon 

 et al. 1984). 



Decreased growth of aquatic organisms during exposure to PCBs is well 

 documented. Concentrations as low as 0.1 ug/1 of Aroclor 1254 produced growth 

 reductions in marine diatoms and a freshwater alga ( Scenedesmus quadricauda ), 

 and altered the population structure of phytoplankton communities (EPA 1980). 

 Among sensitive species of freshwater algae treated with Aroclor 1242, 

 including S^. quadricauda , disruption of internal chloroplast membranes and 

 failure of cytokinesis were the major changes observed (Mahanty et al. 1983). 

 Marine algae exhibited greater-than-expected reductions in photosynthesis when 

 stressed with mixtures of PCBs and DDE (Ernst 1984), and demonstrates the 

 importance of toxicant evaluation of complex mixtures containing PCBs. 

 Decreased shell growth of oysters was reported in acute tests with Aroclor 

 1016 at 10.1 ug/1, with Aroclor 1248 at 17.0 ug/1, with Aroclor 1254 at 14.0 

 ug/1, and with Aroclor 1260 at 60.0 ug/1 (EPA 1980); similar results were 

 reported for shrimp (Ernst 1984). Fry of brook trout held for 48 days at 1.5 

 ug Aroclor 1254/1 also showed decreased growth (Johnson and Finley 1980). 



Reproductive toxicity of PCBs is reported for Baltic flounder 

 ( Platichthys flesus ) when ovaries exceeded 0.12 mg of PCBs/kg fresh weight, 

 and for cyprinid minnows ( Phoxinus phoxinus ) when gonads contained more than 

 24 mg PCBs/kg fresh weight; these are the threshold values beyond which 

 reduced survival of developing eggs can be expected in those species (Ernst 

 1984). Gonadal levels of 24 mg/kg in minnows were obtained with diets of 20 

 mg Clophen A-50/kg for 40 days, followed by 260 days on untreated diets (Ernst 

 1984). Rainbow trout with whole body residues of 0.4 mg Aroclor 1242/kg fresh 

 weight produced eggs with low survival, and numerous (70%) fry deformities 

 (EPA 1980). Rainbow trout eggs with 0.33 mg Aroclor 1254/kg fresh weight 

 incurred 10 to 28% mortality prehatch, and numerous posthatch deformities 

 (Niimi 1983). Eggs and fry of Atlantic salmon with PCB contents of 0.6 to 1.9 

 mg/kg fresh weight, or 14.4-34.0 mg/kg lipid weight, experienced 46 to 100% 

 mortality (Niimi 1983). Embryos of sheepshead minnow ( Cyprinodon variegatus ) 

 containing 7 mg Aroclor 1254/kg fresh weight had low survival ; these values 

 were effected through exposure of parent fish to 0.14 ug Aroclor 1254/1 for 28 

 days (EPA 1980). Brook trout experienced complete reproductive failure during 

 exposure to 200 ug Aroclor 1254/1 for 71 weeks; the no effect level was 0.94 

 ug/1 (EPA 1980). Eggs of the sea urchin, Arbacia punctulata , exposed for one 

 hour to 0.5 mg Aroclor 1254/1 prior to fertilization showed reduced 

 fertilization success and lowered survival; eggs were markedly more resistant 

 to PCBs at the time of insemination and afterwards (Adams 1983). 



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