Abstract |
An in vivo rainbow trout (Salmo gairdneri) preparation was used to evaluate the gill uptake and toxicokinetics of (3H)fenvalerate ((R,S)-alpha-cyano-3-phenoxybenzyl (R,S)-2-(4-chlorophenyl)-3-methylbutyrate), a synthetic pyrethroid insecticide. Fish were exposed to technical-grade fenvalerate (0.28 or 23 ng/L) or an emulsifiable-concentrate formulation (16 ng/L) for 36 to 48 h. No significant effects of emulsifiers or fenvalerate concentration on uptake were observed. The overall mean gill uptake efficiency was determined to be 28.6. Following 8- to 48-h depuration periods, carcass and bile contained 80 to 90 percent and 10 to 20 percent of the gill-absorbed doses, respectively. Analysis of biliary metabolites indicated that the glucuronide of 4'-HO-fenvalerate was the only significant degradation product. Results from the present study suggest that efficient gill uptake does not explain the extreme sensitivity of fish to fenvalerate. Rather, a low rate of biotransformation and excretion may play a significant role in the susceptibility of rainbow trout to the synthetic pyrethroid insecticides. (Copyright (c) 1986 SETAC.) |