The information summarized in this review provides substantial evidence for the widespread presence of genotoxins in drinking water. In many, if not most cases, the genotoxic activity can be directly attributed to the chlorination stage of drinking water treatment. The genotoxic activity appears to originate primarily from reactions of chlorine with humic substances in the source waters. Genotoxic activity in drinking water concentrates has been most frequently demonstrated using bacterial mutagenicity tests but results with mammalian cell assay systems are generally consistent with the findings from the bacterial assays. There is currently no evidence for genotoxic damage following in vivo exposures to animals. In some locations genotoxic contaminants of probable industrial and/or agricultural origin occur in the source waters and contribute substantially to the genotoxic activity of finished drinking waters. The method used for sample concentration can have an important bearing on study results. In particular, organic acids account for most of the mutagenicity of chlorinated drinking water, and their recovery from water requires a sample acidification step prior to extraction or XAD resin adsorption. Considerable work has been done to determine the identity of the compounds responsible for the mutagenicity of organic concentrates of drinking water. Recently, one class of acidic compounds, the chlorinated hydroxyfuranones, has been shown to be responsible for a major part of the mutagenic activity. Strategies for drinking water treatment that have been evaluated with respect to reduction of genotoxins in drinking water include granular activated carbon (GAC) filtration, chemical destruction, and the use of alternative means of treatment (i.e., ozone, chlorine dioxide, and monochloramine). GAC treatment has been found to be effective for removal of mutagens from drinking water even after the GAC is beyond its normal use for organic carbon removal. All disinfectant chemicals appear to have the capacity of forming mutagenic chemicals during water treatment. However, the levels of mutagenicity formed with the alternative disinfectants have been generally less than those seen with chlorine and, especially in the case of ozone, highly dependent on the source water.(ABSTRACT TRUNCATED AT 400 WORDS)

Genotoxic activity of organic chemicals in drinking water.

The influence of different disinfectants on mutagenicity and toxicity of urban wastewater

Pulsed electric field treatment for bacteria reduction and its impact on hospital wastewater

A review of the use of XAD resins to concentrate organic compounds in water

Advanced oxidation and adsorption technologies for organic micropollutant removal from lake water used as drinking-water supply.

The mutagenic potential of water taken at various stages in a water treatment plant which used both chlorination and ozonation as methods for disinfection was investigated. Presented in this paper are some of the results obtained using the Salmonella/microsome test. The results of this investigation indicate that while mutagenic chemicals were produced by chlorination, ozonation of the chemicals in controlled laboratory experiments resulted in a decrease in the mutagenic activity. In observations at the treatment plant, mutagenic chemicals were produced to a lesser extent by ozone treatment than by chlorination. (RJC)

D Burrini

Papers

Effect of ozonation and chlorination on the mutagenic potential of drinking water.