Biliary excretion products of 1-[1-14C]naphthyl-N-methylcarbamate (carbaryl) in rainbow trout (Salmo gairdneri).

Uptake and metabolism of 1-naphthyl-N-methylcarbamate (carbaryl) were studied in rainbow trout (Salmo gairdneri) exposed to 14C-carbaryl in water. A high degree of biliary concentration was indicated by a 24-hr bile to water 14C ratio of nearly 1000:1. Four 14C-labeled compounds were purified from bile and two have been identified with reasonable certainty as unchanged carbaryl and 1-naphthol glucuronide. 5,6-Dihydro-5,6-dihydroxy-1-naphthyl-N-methylcarbamate was tentatively identified by thin-layer chromatography. The results indicate that carbaryl can be metabolized in rainbow trout via pathways similar to those reported in mammals and that bile analysis may be helpful in monitoring fish for exposure to this compound.