Toxicokinetic and metabolic study of dimethylnitrosamine and diethylnitrosamine in crayfish Austropotamobius pallipes

1. The acute toxicities of dimethylnitrosamine and diethylnitrosamine have been evaluated in adult male crayfish Austropotamobius pallipes; LD50 values are 2250 mg/kg and 230 mg/kg, respectively. 2. Toxicokinetic studies of 14C-dimethylnitrosamine and 14C-diethylnitrosamine in crayfish, administered by i.v. injection, show high concentrations of 14C in abdominal muscle and hepatopancreas. Excretion is greater with dimethylnitrosamine, and retention in the tissues, especially the hepatopancreas, is greater with diethylnitrosamine. 3. Metabolites identified in excreta include monomethylnitrosamine from dimethylnitrosamine, and hydroxyethyl-ethyl-, bishydroxyethyl- and carboxyethyl-ethyl-nitrosamine from diethylnitrosamine.