Need to revise the national drinking water regulation for copper.

Copper is an essential micronutrient and a potential toxic metal. The USEPA current maximum contaminant level goal (MCLG, a nonenforceable aspirational health goal) and the required treatment technique action level, both set at 1.3 mg/liter of copper are not adequately protective for infants and children under 10 years of age. Infants and children up to 10 years of age have increased susceptibility to copper toxicity. The two main reasons for the high sensitivity in this population subgroup are the presence of a normally high concentration of copper in the liver during early life and the lack of a fully developed homeostatic mechanism of copper in children under 10 years of age. This sensitive group of infants and children represents approximately 17% of the total U.S. population. The adverse health effects caused by drinking water contaminated with copper are abdominal pain, nausea, vomiting, diarrhea, headache, and dizziness. The proposed drinking water guideline of 0.3 mg/liter for copper was derived by the application of the risk assessment procedures approved by the USEPA. Drinking water containing 0.3 mg/liter of copper will provide approximately 26% of the nutritional requirement of copper. This proposed drinking water guideline (0.3 mg/liter) for copper will adequately protect health of infants, children, and adults.