What Is Copper? Copper is a reddish metal that occurs naturally in rock, soil, water, sediment, and air. Its average concentration in the earth's crust is about 50 parts copper per million parts soil (ppm). Copper also occurs naturally in plants and animals. It is an essential element for all known living organisms including humans and other animals.

        Copper can be easily molded or shaped. Its reddish color is most commonly seen in the U.S. penny, electrical wiring, and some water pipes. It is also found in many mixtures of metals, called alloys, such as brass and bronze.

        How Might I Be Exposed to Copper? Copper is common in the environment. You may be exposed to copper by breathing air, drinking water, eating food, and by skin contact with soil, water, and other copper­containing substances.

        You may be exposed to high levels of soluble copper in your drinking water. The average concentration of copper in tap water ranges from 20 to 75 parts copper per billion parts water (ppb). However, some households have copper concentrations of more than 1,000 ppb. (The EPA standard is 1,300 ppm or 1.3 mg/l). This is because copper is picked up from copper pipes and brass faucets when the water sits in the pipes overnight. After the water is allowed to run for a while, the concentration of copper in the water decreases.

        How Can Copper Affect My Health? Copper is necessary for good health. However, very large single or daily intakes of copper can harm your health. (i.e., you may experience vomiting, diarrhea, stomach cramps, and nausea). Intentionally high intakes of copper can cause liver and kidney damage and even death. Very young children are sensitive to copper, and long­term exposure to high levels of copper in food or water may cause liver damage and death. Copper is not known to cause cancer. We do not know if copper can cause birth defects in humans. The seriousness of the effects of copper can be expected to increase with both level and length of exposure.

        What Levels Protect Human Health? The Environmental Protection Agency (EPA) has determined that the level of copper in water (lakes, streams) should be limited to 1 ppm to protect human health from the toxic properties of copper ingested through water and contaminated aquatic organisms. EPA has also determined that drinking water should not contain more than 1.3 ppm of copper. EPA has developed regulations on the amount of copper released by industry.

        The National Academy of Sciences (NAS) has recommended that 2­3 milligrams copper is a safe and adequate daily intake. This provides enough copper for adult nutrition.