Genotoxicity of the Kishon River, Israel: the application of an in vitro cellular assay

The alkaline comet assay, a sensitive method for DNA strand breaks and alkali labile site detection in individual cells, was employed here as an ecotoxicological monitoring tool for evaluation of genotoxicity in the Kishon River, Israel. This river, the most polluted river in Israel, has recently elicited major public concern with regard to cancer incidences in people who have dived there over many years. Five water samples were collected every odd month throughout the year 2001, from four localities. The comet assay was employed on fish hepatoma cell line RTH-149. Cells were exposed for 2 h, in triplicate, to Kishon water: medium (1:1) samples that were pre-adjusted for pH and salinity percentage levels. Three DNA damage parameters (comet percentages, score of damage, and cumulative tail lengths of the comet), revealed significantly higher genotoxic values in Kishon water-treated cells as compared with the controls (up to 2.4, 3.2, and 3.6-fold, respectively). Part of the sampling sites revealed higher genotoxicity than other polluted sites. The results of this study demonstrate that the comet assay with RTH-149 cells can be successfully applied to a variety of aquatic samples revealing freshwater, marine and estuary conditions. The method found to be fast, sensitive, and suitable for monitoring programs.