Occurrence and control of genotoxins in drinking water: a monitoring proposal

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.