Occurrence and Control of Genotoxins in Drinking Water: A Monitoring Proposal.

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Many studies have shown the presence of numerous organic genotoxins and carcinogens in drinking water. These toxic substances derive not only from pollution, but also from the disinfection treatments, particularly when water is obtained from surface sources and then chlorinated. Most of the chlorinated compounds in drinking water are nonvolatile and are difficult to characterize. Thus, it has been proposed to study such complex mixtures using short-term genotoxicity tests predictive of carcinogenic activity. Mutagenicity of water before and after disinfection has mainly been studied by the Salmonella/microsome (Ames test); in vitro genotoxicity tests have also been performed in yeasts and mammalian cells; in situ monitoring of genotoxins has also been performed using complete organisms such as aquatic animals or plants (in vivo). The combination of bioassay data together with results of chemical analyses would give us a more firm basis for the assessment of human health risks related to the consumption of drinking water. Tests with different genetic end-points complement each other with regard to sensitivity toward environmental genotoxins and are useful in detecting low genotoxicity levels which are expected in drinking water samples.Significance for public healthThe provision of a safe drinking water is an important public health problem. Many studies have shown the presence of numerous genotoxins and carcinogens in drinking water. These toxic substances derive not only from pollution, but also from the disinfection treatments, particularly when water is obtained from surface sources and then chlorinated. The potential health risks of disinfection by-products (DBPs) from drinking water include cancer and adverse reproductive outcomes. People are exposed to disinfected drinking/shower/bathing water as a mixture of at least 600 identified DBPs and other toxic compounds via dermal, inhalation, and ingestion routes. Many of these substances are present in trace concentration, hardly detectable by chemical standard analysis. The monitoring of environmental genotoxins by short-term bioassays could allow a better evaluation of the global human exposure to water genotoxins and could help health officers and drinking water managers to reduce genotoxic hazards and distribute high quality drinking water.