HEALTH ASPECTS OF ORGANICS IN DRINKING WATER (H 4298CD) Final Report to the Department of the Environment
Report No DWI0223

Mar 1985

SUMMARY

In April 1977, the Department of the Environment placed a contract with the Water Research Centre with the overall objective of evaluating the possible health effects of long term consumption of drinking water derived from sources containing sewage effluent or industrial effluent. This contract ended in March 1981 but was renewed for w years finally ending in March 1984. During the second contract, the objective was modified so that the emphasis was changed from a specific investigation of re-use to an assessment of organic compounds in general.

This final contract report summarises the main lines of investigation in each of the four components of the programme of work: epidemiology, mutagenicity, water quality studies and toxicology. The principal findings are summarised and discussed briefly.

The overall conclusion of the original contract concerning the adverse health effects of re-use was that although potentially harmful chemicals are present in water at very low levels, their presence can not be specifically attributed to re-use. Assessment of the toxicology of these compounds led to the conclusion that any risk was probably of a low order. The epidemiological studies of community health also suggested that the effects of re-use were very small. However, the application of short-term screening tests has shown that mutagens will normally be present in drinking water as a result of water treatment chlorination. It has also been shown that much of the organic matter remains unidentified and is consequently of unknown significance to health. Therefore, in terms of the objective of the second phase of the contract, that of investigating the presence of organic compounds in general rather than re-use in particular, the effect of such compounds on health is probably small but remains unquantified.

In order to better assess and quantify these risks to health a number of recommendations for further work are made including: studies of disinfection byproducts; characterisation of non-volatile organics; characterisation of sources of organic pollution of groundwater and contamination in distribution; assessment of the effects of treatment on mutagenic activity and the characterisation of mutagens in water; development of mutagenicity and cytotoxicity assays based on higher cell systems; fundamental research into those aspects of toxicology relating to low doses, long-term exposure and complex mixtures and into the mathematical techniques for extrapolating from high to low doses; epidemiological studies based on individuals rather than geographical areas.

Copies of this report may be available as an Acrobat pdf download under the 'Pre 2000 Reports' heading on the DWI website.