Safety guidelines for copper in water.

It is important for public health authorities to set a scientifically sound guideline value for the safe ingestion of copper in drinking water. To date, the principal health-based guideline values have been set by the US Environmental Protection Agency (1.3 mg Cu/L) and the World Health Organization (2.0 mg Cu/L). However, close examination of the data and assumptions used in the derivation of these values reveals a paucity of scientifically defensible information. Several international groups are now reviewing this issue, and others have begun epidemiologic studies that may provide useful copper exposure and toxicity data. Investigations of acute copper toxicity in human populations are most likely to affect future revisions of the guideline value for copper in drinking water.