Chemical accumulation and biotransformation enzyme activities of rainbow trout embryos in waterborne exposure to PCB-77

The penetration potential of a lipophilic pollutant, 3,3',4,4'-tetrachlorobiphenyl (PCB-77), and the exposure time needed to activate the monooxygenase system of fish at the advanced embryonal stage were studied. Rainbow trout (Oncorhynchus mykiss) embryos were exposed to different doses (0, 1, 10, and 100 mu g l(-1)) of PCB-77. Results indicated rapid and high accumulation of PCB-77 into the eggs. At the lowest rest concentrations (1 and 10 mu g l(-1)), all of the free PCB-77 was absorbed by embryos in three days. At the highest concentration (100 mu g l(-1)), the accumulation limit (similar to 144 ng embryo(-1)) of the chemical was already reached after first exposure day. The microsomal CYP1A monooxygenase system (EROD) was shown to be a sensitive indicator of embryonic exposure, being induced at the low (1 mu g l(-1), 10 ng embryo(-1)) PCB-77 concentrations and after a short (three day) exposure time. (C) 1998 Elsevier Science Ltd. All rights reserved.