Abstract
Waters from the Sakawa River and its tributaries were tested by conducting a colony forming assay with Bulb 3T3 A31-1-1 and Vero cells, both of which showed good sensitivities to the test waters and some pesticides. The waters were also subjected to standard water analyses, such as bacterial count, concentrations of nitrate and nitrite, chemical oxigen demand (COD), and electrical conductivity. The river waters were collected 7 times at 13 points from August 1995 to July 1997. Relative cell plating efficiencies at maximum concentrations of the river waters (net river water in the medium was 81%) were used to compare the cytotoxicities of the waters. The ranking of each water in terms of the given parameters was determined with the plating efficiency, or each parameter of chemical analysis, then in cells (total ranking of cytotoxicity), or in the water analysis (total ranking of standard water analysis). On the whole, the results of total ranking of cytotoxicity and those of standard water analysis were strongly correlated, although some waters showed strong cytotoxicity even when judged as ‘clean waters’ by the water analysis. Overall, the data suggest the usefulness of biological testing to detect complex pollutants in environmental waters.
