POSSIBLE EFFECTS OF POLYCHLORINATED-BIPHENYLS ON SEX DETERMINATION INRAINBOW-TROUT

Aqueous exposure of newly hatched rainbow trout (Oncorhynchus mykiss) larvae to Aroclor 1260 resulted in altered sex ratios and severe gonad al abnormalities in juvenile females. The proportion of females decrea sed from 41.9% in combined controls to 31.6 to 36.1% in groups that ac cumulated 2.5 mu g/g Aroclor 1260 after 3-h immersions, although this decrease was not statistically significant (p = 0.057). A total of 18. 2% of the females in the treatment group that accumulated 2.1 mu g/g A roclor 1260 had abnormal gonads as compared to 2.7% in combined contro ls (p = 0.001). Abnormalities were characterized by inconsistent or ex tremely limited development of oocytes. Although further work is requi red to validate these results, this study suggests that environmentall y realistic tissue concentrations of Aroclor 1260 may disrupt sexual d evelopment in female trout.