Assessment of the cytotoxicity and genotoxicity of haloacetic acids using microplate-based cytotoxicity test and CHO/HGPRT gene mutation assay.

Haloacetic acids (HAAs) are the second most prevalent class of disinfection byproducts found in drinking water. The implications of HAAs presence in drinking water are a public health concern due to their potential mutagenic and carcinogenic effects. In the present study, we examined the cytotoxic and genotoxic effects of six common HAAs using a microplate-based cytotoxicity test and a hypoxanthine-guanine phosphoribosyltransferase (HGPRT) gene mutation assay in Chinese hamster ovary K1 (CHO-K1) cells. We found that their chronic cytotoxicities (72h exposure) to CHO-K1 cells varied, and we ranked their levels of toxicity in the following descending order: iodoacetic acid (IA)>bromoacetic acid (BA)>dibromoacetic acid (DBA)>chloroacetic acid (CA)>dichloroacetic acid (DCA)>trichloroacetic acid (TCA). The toxicity of IA is 1040-fold of that of TCA. All HAAs except TCA were shown to be mutagenic to CHO-K1 cells in the HGPRT gene mutation assay. The mutagenic potency was compared and ranked as follows: IA>DBA>BA>CA>DCA>TCA. There was a statistically significant correlation between cytotoxicity and mutagenicity of the HAAs in CHO-K1 cells. The microplate-based cytotoxicity assay and HGPRT gene mutation assay were suitable methods to monitor the cytotoxicity and genotoxicity of HAAs, particularly for comparing the toxic intensities quantitatively. 2010 Elsevier B.V. All rights reserved.