Assessment of the human risk associated with the presence of carcinogenic compounds in drinking water.

Both organic and inorganic contaminants which have been implicated in causing cancer in man or, more commonly, in laboratory animals can be found in drinking water. Apart from arsenic there are none for which there is convincing epidemiological evidence of a significant risk to man. However environmental epidemiology is fraught with difficulties. There are also difficulties in interpreting laboratory animal data and extrapolating this to the low concentrations found in drinking water although mathematical models can be very useful if used sensibly. There is a danger that the rather extreme public perception of cancer could lead to over regulation of some contaminants in water, possibly with an increase in risk from other hazards such as microbiological contamination.