Copper in drinking water, Nebraska, 1994.

Area of Science:

• Environmental Health
• Epidemiology
• Public Health

Background:

• In 1993, Nebraska's drinking water copper (Cu) levels frequently exceeded the EPA action level of 1.3 mg/L.
• Gastrointestinal (GI) illness is a common public health concern, and water quality is a potential contributing factor.

Purpose of the Study:

• To investigate the association between elevated copper concentrations in drinking water and the incidence of gastrointestinal illness.
• To determine if specific copper exposure levels correlate with increased risk of GI symptoms.

Main Methods:

• A cohort study interviewed households with varying 1993 drinking water Cu levels ( > 3 mg/L, 2-3 mg/L, < 1.3 mg/L).
• Cases were defined by rapid onset of vomiting or nausea with abdominal pain.
• Water samples were resampled to validate exposure, and cohort status was reassessed in December 1994.

Main Results:

• No association was found between 1993 copper levels and GI illness status in 1994.
• Relative risks (RR) for GI illness were not significantly elevated in households with Cu > 3 mg/L (RR = 1.03) or 2-3 mg/L (RR = 0.50) compared to < 1.3 mg/L.
• Subsequent resampling in December 1994 also revealed no association between GI illness and copper exposure.

Conclusions:

• Elevated copper levels in Nebraska's drinking water in 1993 were not linked to an increased risk of gastrointestinal illness in the studied population.
• The findings suggest that copper in drinking water, at the levels investigated, is unlikely to be a significant cause of acute GI illness.
• Water quality monitoring and public health advisories regarding copper should consider these epidemiological findings.