Effects on DNA and cell viability of treated water contaminated with Cylindrospermopsis raciborskii extract including cylindrospermopsin

It is well known that chlorine can oxidize cyanotoxins, thus increasing water potability. Considering that the first steps of conventional treatment do not remove the toxins, the aim of this study was to investigate the toxicity of treated water containing cylindrospermopsin after chlorine addiction. It was analyzed DNA damage and viability of HepG2 cells exposed to the following treatments: cylindrospermopsin (CYN) containing extract of Cylindrospermopsis raciborskii; this same extract added to treated water; non toxic C. raciborskii (all extracts at concentration of 0.1, 0.5 and 1 μg of dry material mL-1), and treated water only. Cells were exposed for 24, 48 and 72 hours. A decrease in cell viability of HepG2 cells was observed after the treatment with toxic C. raciborskii extract (at 0.5 and 1 μg mL-1 for all times of exposure) and the toxic extract with treated water at the two higher concentrations at 48 and 72 hours. Comet assays also revealed DNA damage in HepG2 cells under toxic C. raciborskii extract. Data indicated that chlorine can prevent damage to DNA and to cell viability in most of conditions. In conclusion, chlorine addiction in conventional water treatment has a potential to provide protection or reduce toxic effects of CYN.