Lethal and sublethal effects of marine sediment extracts on rainbow trout hepatocytes

Genotoxicity and cytotoxicity were evaluated in rainbow trout hepatocytes exposed to organic sediment extracts obtained from Pointe aux Meules harbour in the Magdalen Islands, Canada. Hepatocytes were exposed to concentrations of sediment extracts for 24 h at 15 degrees C. After this incubation period, they were analyzed for viability, cytochrome P450 1A activity, and genotoxicity. Metallothionein (MT) levels were also determined in order to assess heavy metal exposure. All sediment extracts displayed cytotoxicity to rainbow trout hepatocytes. Half (53%) of the extracts proved to be genotoxic to trout hepatocytes, while cytochrome P450 1A induction occurred with 70% of the sediment extracts. Interestingly, 40% of the extracts had the capacity to elicit induction of MT in trout hepatocytes. MT induction by exposure of trout hepatocyte to organic extracts suggests the presence of metals. The lack of correlation between the chemical and toxicological data suggests that chemical interactions may be responsible for the toxic manifestations in trout hepatocytes or that unknown chemicals are at play.