In order to examine whether cytotoxicity test is available as bioassay of water micropollutants, cytotoxicities of 40 chemicals, which have been reported to occur in drinking water, were investigated using 3 different types of cultured cells including HL-60 cells, mouse peritoneal macrophages and rat liver hepatocytes, and the results were compared with their mutagenicity and carcinogenicity. Cancer promotion activity was assayed by use of morphological change of HL-60 cells. Lethality of chemicals was measured with trypan-blue exclusion test of HL-60 cells or lactose dehydrogenase released from rat hepatocytes. Influence of chemicals on cell functions was examined with phagocytic activity of macrophages and glycogenolytic activity of hepatocytes. Some of the chemicals showed strong cytotoxicities which depended on the structure of chemicals and the nature of cells, while cancer promotion activity was not found in any sample. Among the 3 tests, viability test using HL-60 cells was the most susceptible to the chemicals. No correlation was observed between the results of cytotoxicities and their mutagenicity. The results indicate that the combination of some cytotoxicity tests should become effective both to estimate the safety of drinking water and to identify the hazardous micropollutants.

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In order to establish the method of bio-assay for the safety of drinking water, mutagenic activity, promotion activity for cancer, cytotoxicity and liposomal membrane damage of micropollutants in water were studied. The dissolved substances in water were recovered from raw, chlorinated, and rapid-filtrated waters by adsorption with XAD-2. Mutagenicity of the recovered substances was estimated with Ames Salmonella mutagenicity test. Cancer promotion activity was assayed by use of morphological change of HL-60 cell. Cytotoxicities of the recovered substances were evaluated with the cultured cells, HL-60 and mouse peritoneal macrophages. Some of the samples showed strong direct mutagenicity and cytotoxicities, while cancer promotion activity was not found in any sample. No correlation was observed between the results of mutagenicity and cytotoxicities, while the results of cytotoxicities related to those of liposomal membrane damage. The findings indicate that the combination of mutagenicity test with the other bio-assay such as cytotoxicity should be necessary to secure the safety of drinking water.

Cytotoxicities were investigated with chemicals including pesticides, industrial materials, and chlorination by‐products using colony formation inhibition of L‐929 cells and membrane damage of “liposomes” to develop the simple bioassays for estimation of human hazardous micropollutants in water. Some chemicals including pesticides and chlorination by‐products strongly inhibited colony formation of L‐929 cells, and the inhibition was dose dependent. But most cytotoxic substances did not increase membrane permeability of liposomes, suggesting that Cytotoxicity of these chemicals does not arise from direct damage of cell membranes. The IC10 and IC50,10 and 50% inhibition concentrations, were obtained from the dose‐response curve of colony formation. The IC10 showed good correlation (r = 0.75) to LD50 of rat by intraperitoneal administration but not to those by oral administration. The results were compared to those with viability of HL‐60 cells, phagocytic activity of mice peritoneal macrophages, glycogenolysis, and LDH release of rat liver hepatocytes. The susceptibilities were largely different among these Cytotoxicity tests, and the colony formation inhibition test gave similar results to the viability of HL‐60 cells. The principle of “cytotcxicity matrix” was developed from the comparison of cytotoxicities for each chemical. The characteristic relation was found between the chemical structure and the pattern of the Cytotoxicity matrix, indicating that the Cytotoxicity matrix may be useful for predicting the origin and nature of micropollutants. © 1994 by John Wiley & Sons, Inc..