Effects of treated municipal wastewater on the hepatic, xenobiotic, and steroid metabolism in trout

Abstract

The effects of treated municipal wastewater on the liver microsomal in vitro metabolism of 4-androstene-3,17-dione, benzo[ a]pyrene (BP), ethylmorphine (EM), and p-nitroanisole (PNA) in rainbow trout, Salmo gairdneri, were studied. Exposure of fish to waste water for 2 weeks markedly increased the PNA- O-demethylase and BP-hydroxylase activities, while EM- N-demethylase activity was decreased. Wastewater treatment increased the cytochrome P-450 content and NADPH cytochrome c reductase activity when expressed on a per gram liver but not on a per miligram protein basis. LSI and microsomal protein content were significantly higher in wastewater-treated fish when compared to those of controls. In addition, wastewater treatment altered the liver microsomal metabolism of androstenedione. Thus, 6β-hydroxylase activity was decreased in wastewater-treated fish, while 17-hydroxysteroid oxidoreductase activity increased. The results indicate the presence of polycyclic aromatic hydrocarbons in treated municipal wastewater.