Metals in Drinking Water

Metals are inorganic substances that occur naturally in geological formations. Some metals are essential for life and are naturally available in our food and water. In addition to metals essential for life, drinking water may contain metals which cause chronic or acute poisoning.

Trace amounts of metals enter our water supplies naturally as rain percolates through rock; dissolving minute quantities into the water. This water enters larger water bodies which we then use as resources for drinking water. Contamination of our water resources by poisonous metals occurs largely due to human activity. These activities include industrial processes, such as electronics and mining, agricultural activities, and discarding of wastes in landfills.

The EPA has set maximum contaminant levels (MCL) for metals including arsenic, barium, cadmium, chromium, lead, copper, mercury, selenium, nickel, thallium, antimony, and beryllium. This means that public water supplies are monitored for these metals regularly. Private systems are not monitored. It is up to the owner or consumer to test and treat their water..

The most ubiquitous of toxic metals in drinking water is lead. Lead and copper can leach from water pipes and soldered joints which deliver water to our tap. This is especially a problem in older homes. The toxic effects of lead can lead to nerve and brain damage. Children are especially sensitive. Exposure may also lead to kidney damage, and blood disorders (1). The Environmental Protection Agency's maximum concentration level for lead is 0.005 mg/L in water.

Copper, a by-product of pipe corrosion, acid mine drainage, iron and steel production, and sewage treatment can cause anemia, digestive disturbances and liver and kidney damage at high exposure levels (1). The MCL for copper in drinking water is 1.3 mg/L.

Chromium, a by-product of mining, chrome plating, cement production, detergents, and incineration can cause liver and kidney damage (1). The MCL for chromium in drinking water is 0.05 mg/L.

External Links to information about metals in your drinking water:

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1. Kansas Extension Office

This page was prepared by T.L. Pedersen , UCD EXTOXNET FAQ Team.
June 1997