A review of the science behind drinking water standards for copper.

Copper is an essential element, being a vital component in several enzyme systems. Some intake, therefore, is necessary for human health. At high intakes, however, it can have toxic effects. This paper uses a quality audit framework to review the strength of the science underlying the setting of standards for copper in drinking water intended for human consumption. The two copper standards examined are the revised EU drinking water directive (98/83/EC) of 2 mg/l, based on WHO guidelines, and the USEPA treatment technique action level of 1.3 mg/l. Examination of these standards reveals that neither has a firm scientific basis, accordingly both are difficult to justify from a scientific standpoint, a situation that is worrying in both health and policy terms.