Toxicity assessment of organic compounds in drinking water in the Netherlands.

In a recent survey of organic compounds present in drinking water of twenty cities in The Netherlands, it was found that only a minor fraction (10%) of the total organic content could be identified. It appeared that drinking water prepared from polluted surface water contains more organic compounds with carcinogenic and mutagenic properties than water prepared from groundwater. The concentration of most of the organic constituents identified was generally below the microgram/litre level. It is not expected that circumstances will occur, that these compounds will be present in quantities, which are acutely toxic for consumers. On the other hand it cannot be excluded that certain organic compounds, in particular carcinogens and mutagens, may cause chronic toxic effects as a result of life time consumption of such contaminated drinking water. Therefore an epidemiological study was started in The Netherlands in which cancer mortality was related to the raw water source used for drinking water and the level of organic constituents. Preliminary results of the epidemiological study are presented. Furthermore a limited survey was carried out whereby drinking water of six cities was investigated for the presence of organic genotoxic compounds. The results of this survey led to the decision to extend this investigation to 19 cities. Finally, preliminary results regarding the characterization of the organic genotoxic compounds, present in drinking water, will be discussed.