Copper

Summary

Copper is an essential element in our diet, but too much can cause vomiting, diarrhea, stomach cramps and nausea. It has also been associated with liver damage and kidney disease. 

The body’s natural mechanisms for maintaining proper levels of copper develop after age one, so children younger than one are more vulnerable to its toxic effects. Copper in tap water primarily comes from plumbing pipes. This water,  especially when hot, can leach copper from pipes, so it should not be used to prepare infant formula.

Water utilities are required to sample water in a subset of customers’ homes served by the utility to determine if excessive copper might be a problem.

The federal action level for copper in drinking water is triggered whenever the level of copper in more than 10 percent of the tap water samples collected by a water system is greater than 1.3 parts per million, or ppm. The system then has to take steps to reduce copper in its water.

But this action level is not sufficient to protect susceptible populations, such as infants and people with a rare inherited metabolic disorder known as Wilson’s disease. 

California set a public health goal for copper at 0.3 ppm to protect infants and children from the gastrointestinal effects of excess copper. Public health goals are not legally enforceable.

How does copper get into tap water?

Copper occurs naturally and the levels found in the rivers and lakes that supply drinking water are typically low. The main reason copper is in tap water is because copper pipes used in household plumbing can dissolve over time. Corrosive water conditions, such as acidity or a high concentration of aluminum or chlorine in water, can increase copper leaching.

According to the Minnesota Department of Health, homes with new copper pipes are most at risk of leaching. That’s because minerals build up on the inside of pipes over time. Once this coating has developed, water has less contact with the pipe surface and is less likely to pick up copper. 

The longer the water stays in pipes, the more copper will leach into it. In homes with copper pipes – especially new ones – water should be flushed from the tap if it has not been in use for more than six hours before anyone drinks it.

What are the toxic effects of copper in drinking water?

At levels typically detected in U.S. tap water, copper primarily poses a concern for newborn children and infants, as well as for individuals with a genetic copper metabolism disorder.

The amount of copper infants and children need to function is much lower than what adults need. And infants younger than one year old are more susceptible than adults to excess copper, due to their inability to regulate copper. Infants may experience diarrhea, weight loss and even liver cirrhosis if they drink water with too much copper – especially formula made with it.

About one percent of Americans have Wilson’s disease, a genetic predisposition to increased copper retention. They are susceptible to increased copper toxicity that may affect the liver, kidneys and brain, as reported in 2000 by the National Research Council Committee on Copper in Drinking Water.

What can be done to reduce exposure to copper in drinking water?

Copper, like lead, is removed with specialized treatment techniques that water utilities use to control the corrosiveness of their water.

According to the Environmental Protection Agency’s Lead and Copper Rule, 1.3 ppm is the trigger for utilities to act. Whenever this action level is exceeded in more than a tenth of samples collected in a water system, the utility must take additional steps to decrease leaching. These may include adding a corrosion inhibitor, such as phosphate, or adjusting the water chemistry.

If you have copper pipes in your home – especially if it’s a new home or the pipes are new – flush the tap for 15 to 30 seconds before use to remove water that has been sitting in pipes for hours or overnight.

For infants younger than one year old and anyone with a copper metabolism disorder, filter water using an NSF-certified filter rated to reduce copper.

Use cold water for cooking because hot water dissolves more copper. It is especially important not to use hot water for making baby formula.

If you use a private water well, check its acidity and copper levels at the tap. If the well water is acidic, consider a treatment system to reduce pH, which will decrease copper leaching.

References

Agency for Toxic Substances and Disease Registry, Toxicological Profile for Copper. 2004. Available at www.atsdr.cdc.gov/toxprofiles/tp132.pdf.

California Office of Environmental Health Hazard Assessment, Public Health Goal for Copper in Drinking Water. California Environmental Protection Agency, 2008. Available at www.oehha.ca.gov/media/downloads/water/chemicals/phg/copperphg020808_0.pdf.

Centers for Disease Control and Prevention, Copper and Drinking Water from Private Wells. 2015. Available at www.cdc.gov/healthywater/drinking/private/wells/disease/copper.html.

H.H. Dieter et al., Early Childhood Cirrhosis (ECC) in Germany Between 1982 and 1994 With Special Consideration of Copper Etiology. European Journal of Medical Research, 1999, 4(6):233–242.

J.W. O’Donohue et al., Micronodular Cirrhosis and Acute Liver Failure Due to Chronic Copper Self-Intoxication. European Journal of Gastroenterology and Hepatology, 1993, 5:561–562.

L. Stenhammar. Diarrhea Following Contamination of Drinking Water with Copper. European Journal of Medical Research, 1999, 4(6):217-218.

M. Araya et al., Determination of an Acute-No-Observed-Adverse-Effect Level (NOAEL) for Copper in Water. Regulatory Toxicology and Pharmacology, 2001, 34:137–145.

M. Araya et al., Community-Based Randomized Double-Blind Study of Gastrointestinal Effects and Copper Exposure in Drinking Water. Environmental Health Perspectives, 2004, 112(10):1068–1073.

M. Edwards and J.C. Rushing, Effect of Aluminum Solids and Chlorine on Cold Water Pitting of Copper. Corrosion Science, 2004, 46(12):3069-3088.

M. Olivares et al., Nausea Threshold in Apparently Healthy Individuals Who Drink Fluids Containing Graded Concentrations of Copper. Regulatory Toxicology and Pharmacology, 2001, 33(3):271–275.

Maryland Department of Housing and Community Development, Pinhole Leaks in Copper Plumbing. Task Force Study: Final Report. 2004. Available at www.wsscwater.com/files/live/sites/wssc/files/PDFs/Study%20of%20Pinhole%20leaks%20Report_1503042.pdf.

Minnesota Department of Health, Copper in Drinking Water Health Effects and How to Reduce Exposure. 2005. Available at www.health.state.mn.us/divs/eh/water/factsheet/com/copper.pdf.

National Research Council Committee on Copper in Drinking Water, Copper in Drinking Water. 

National Academies Press, 2000. Available at www.ncbi.nlm.nih.gov/books/NBK225399/.

World Health Organization, Copper in Drinking-water: Background Document for Development of WHO Guidelines for Drinking-water Quality. 2004. Available at www.who.int/water_sanitation_health/dwq/chemicals/copper.pdf.