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Date: March 2, 2000
Contacts: Bill Kearney, Media Relations Associate
Megan O'Neill, Media Relations Assistant
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Allowable Levels of Copper in Drinking Water Should Not Be Increased Until Studies Are Done

WASHINGTON -- The federal government should not increase the maximum level of copper allowed in drinking water, because higher levels could lead to liver poisoning in infants and children with certain genetic disorders, according to a new report from the National Academies' National Research Council. Instead, the government should conduct studies on the health effects of copper in these sensitive populations, the committee that wrote the report urged.

Under the Safe Drinking Water Act, the Environmental Protection Agency (EPA) is required to establish the concentrations of contaminants that are permitted in public drinking water supplies. EPA has set a goal for copper at a maximum allowable level of 1.3 mg per liter of drinking water, to protect against short-term gastrointestinal tract problems. However, some states, such as Nebraska and Delaware, have difficulty maintaining copper levels below this goal.

Because some recent population studies have reported no adverse health effects from ingesting copper at higher concentrations, questions have been raised about the validity of the science on which EPA based its goal for drinking water. Some people believe that the goal might be unnecessarily low, and others believe that some individuals might get sick from copper levels at or below EPA's current goal. In response to these concerns, Congress asked the Research Council for an independent review of the scientific and technical basis for EPA's goal for copper in drinking water.

Too much copper can cause several health problems, the committee said. Excessive doses can cause nausea, vomiting, and diarrhea. Long-term exposure can lead to copper poisoning, especially in people whose bodies have trouble regulating copper because of certain genetic disorders or illnesses, such as Wilson's disease. Severe cases of copper poisoning have led to anemia, liver poisoning, and kidney failure.

"We reviewed a wide range of data on exposure to copper from both food and water and concluded that EPA's current level protects sensitive individuals from the acute effects of excess copper," said committee chair Richard Bull, senior staff scientist, Battelle Pacific Northwest Division, Richland, Wash. "We assume this level is protective to people with chronic disease, as well. But we need more information about the total copper doses received from drinking water, along with a better idea of how many people are sensitive to copper and what happens to them when they are exposed. Once this information has been gathered, the current level should be re-evaluated. We don't know enough to change it right now, but if it is raised, there may be harm done to children with a defective gene."

In the past, people with Wilson's disease, which is caused by a defect in a gene that is important in eliminating excess copper from the body, were considered such a small and special portion of the population that it was thought best to protect them by limiting their copper intake individually. However, new evidence suggests that brothers and sisters of people with Wilson's disease also may be at risk, even though they do not have the disease themselves. This in turn suggests that carriers -- people with one copy of the defective gene -- also could be at risk.

Children who carry the gene would be at particular risk because their consumption of water is greater than adults in proportion to their size. Although Wilson's disease is found in only 1 out of 40,000 people in the United States, the committee believes that as much as 1 percent of the population may carry the gene for the disease. But there is no test available yet to identify individuals that could be at risk.

Copper is an essential mineral nutrient that is found in soil and plants. Most copper contamination in drinking water is the result of corrosion of copper pipes or fittings. Corrosion can occur from water that is high in acidity and high in temperature. Corrosion also can be caused by water that is "soft," or free of magnesium or calcium salts that create a protective coating inside the pipe.

In 1989 the Institute of Medicine estimated that adults could safely ingest 1.5 to 3.0 mg of dietary copper per day and infants could consume 0.4 to 0.6 mg per day to maintain good health. Generally, the copper that people ingest through their daily diet falls within this range, and typically only a small fraction of an individual's copper intake comes from drinking water. However, water characteristics in some states and municipalities are conducive to greater leaching of the mineral into drinking water. The length of time that water sits in copper pipes also can greatly increase the mineral's concentration to several milligrams per liter of water. The concentration of copper decreases in water that has been running from the tap for a few minutes.

The committee's work was funded by the EPA. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit organization that provides advice on science and technology under a congressional charter. A committee roster follows.

Read the full text of COPPER IN DRINKING WATER for free on the Web, as well as more than 1,800 other publications from the National Academies. Printed copies are available for purchase from the National Academy Press Web site or at the mailing address in the letterhead; tel. (202) 334-3313 or 1-800-624-6242. Reporters may obtain a pre-publication copy from the Office of News and Public Information at the letterhead address (contacts listed above).

Commission on Life Sciences
Board on Environmental Studies and Toxicology

Committee on Copper in Drinking Water

Richard J. Bull, Ph.D. (chair)
Senior Staff Scientist
Molecular Biosciences Department
Battelle Pacific Northwest Laboratory
Richland, Wash.

Michael Aschner, Ph.D.
Professor of Physiology and Pharmacology
Wake Forest University School of Medicine
Winston-Salem, N.C.

George J. Brewer, M.D.
Departments of Human Genetics and Internal Medicine
University of Michigan
Ann Arbor

Edward D. Harris, Ph.D.
Department of Biochemistry and Nurtition
Texas A&M University
College Station

Carl L. Keen, Ph.D.
Department of Nutrition
University of California

Karl T. Kelsey, M.D.
Departments of Cancer Cell Biology and Environmental Health
Harvard School of Public Health

F. William Sunderman Jr., M.D.
Visiting Scholar
Department of Chemistry and Biochemistry
Middlebury College
Whiting, Vt.

Joyce S. Tsuji, Ph.D.
Bellevue, Wash.

Lauren A. Zeise, Ph.D.
Reproductive and Cancer Hazard Assessment Section
California Environmental Protection Agency


Carol A. Maczka, Ph.D.
Study Director