Abstract
To evaluate the toxicity other than mutagenicity or carcinogenicity present in the water environment, in vitro cytotoxicity tests using cultured mammalian cells were utilized. Cytotoxicity was estimated based on the changes in viable cell numbers of primary rat cerebellar cells, rat pheochromocytoma cell PC12h, and normal rat kidney epithelial cell NRK-52E. Evaluation of these in vitro systems was performed by testing reference chemicals proposed by MEIC (Multicenter Evaluation of In Vitro Cytotoxicity), an international program for the validation of in vitro cytotoxicity tests.
When cells in culture were exposed to landfill leachate for 48 hours, viable cell numbers decreased dose dependently. However, fractions prepared by condensation and extraction from the leachates showed much less effects on the viable cell numbers. Their individual cytotoxicity did not account for that of unfractionated leachate, suggesting that component(s) with higher cytotoxicity may not be successfully recovered during the condensation and extraction process.
Among the silica-gel column fractions of acetone-extracts of sediment samples, fractions eluted with acetone showed the highest cytotoxicity.
These results indicate that the cytotoxicity of water samples like landfill leachates or of their extracts can be detected with the present assay system but toxic components may not be recovered quantitatively during the condensation and extraction process.
