Science Notes: Features

Common Trace Metals Found in Water

Trace metals are far from the only pollutants in our waters. Bacteria like E. coli and cryptosporidium may be your greatest health risk from water. (For example, a cryptosporidium outbreak killed 12 people in Milwaukee in 1993.)

But that doesn't mean that trace metals aren't a problem. For example, lead pollution has killed tundra swans and caused brain damage in children along the Coeur d'Alene River in Idaho. Exposure to trace metals in air and water continues to be an occupational hazard for workers in the mining and smelting industries. Contaminated soil can be a significant source of exposure for children, who ingest on the average over an ounce of dirt a day. Wash those hands, kids!

The table below shows the metals that were studied by Flegal and Creasey at a contaminated site in California, explains what they are used for and identifies some of their possible health effects. Not all of these metals are bad! In particular, small amounts of chromium, copper and zinc are essential nutrients. See the Web page of the Agency for Toxic Substances and Disease Registry (ATSDR), called ToxFAQs, for more detailed information.

Kind of Metal

Possible Health Effects

Used For

How You Might be Exposed

Lead
High Levels - Damage to brain, kidneys, immune system, possibly to reproductive system. Probable carcinogen. "Lead can affect almost every organ and system in your body." - ATSDR. Batteries, ammunition; formerly used in paint, gasoline, solder for pipes. Contaminated food, soil, paint, water. (Lead dissolves in soft water.)

Cadmium
Lung irritant. Long Term - May cause kidney disease, fragile bones. Probable carcinogen. Can build up in body for decades. Battery production, solder, pigments. Tobacco smoke. (Smokers have twice as much cadmium in their bodies as nonsmokers.) Sewage sludge, contaminated fish or plants. Concentrations in water are rarely high enough to cause human health problems.

Chromium
An essential nutrient in small amounts. Very large amounts can cause ulcers, liver, kideney damage. Some chromium compounds cause cancer. Steel, dyes and pigments, chrome plating, leather tanning, wood preserving. Occupational exposure, contaminated water or soil near waste sites.

Copper
An essential nutrient. Non-toxic to normal adults. Wilson's Disease, a rare genetic disease in which the body cannot get rid of copper, leads to liver, brain damage and death by age 30-40 (if untreated). Copper pipes. Added to water supplies to prevent algal blooms. Shellfish, nuts, liver, chocolate, mushrooms.

Nickel
Very high levels can affect heart, kidneys, lungs. Skin allergies in some people. Stainless steel, plumbing, engines, nickel plating, batteries. Occupational exposure, contaminated soil or plants.

Zinc
Essential nutrient in small amounts. Large amounts can cause anemia, stomach cramps, pancreas damage, nausea. Coatings, batteries, steel. Zinc compounds are used in paint, rubber, dyes, wood preservatives, skin creams. Contaminated water, fish. (Zinc does not build up in plants.) Overconsumption of dietary supplements.

Kind of Metal	Possible Health Effects	Used For	How You Might be Exposed
Lead	High Levels - Damage to brain, kidneys, immune system, possibly to reproductive system. Probable carcinogen. "Lead can affect almost every organ and system in your body." - ATSDR.	Batteries, ammunition; formerly used in paint, gasoline, solder for pipes.	Contaminated food, soil, paint, water. (Lead dissolves in soft water.)
Cadmium	Lung irritant. Long Term - May cause kidney disease, fragile bones. Probable carcinogen. Can build up in body for decades.	Battery production, solder, pigments.	Tobacco smoke. (Smokers have twice as much cadmium in their bodies as nonsmokers.) Sewage sludge, contaminated fish or plants. Concentrations in water are rarely high enough to cause human health problems.
Chromium	An essential nutrient in small amounts. Very large amounts can cause ulcers, liver, kideney damage. Some chromium compounds cause cancer.	Steel, dyes and pigments, chrome plating, leather tanning, wood preserving.	Occupational exposure, contaminated water or soil near waste sites.
Copper	An essential nutrient. Non-toxic to normal adults. Wilson's Disease, a rare genetic disease in which the body cannot get rid of copper, leads to liver, brain damage and death by age 30-40 (if untreated).	Copper pipes. Added to water supplies to prevent algal blooms.	Shellfish, nuts, liver, chocolate, mushrooms.
Nickel	Very high levels can affect heart, kidneys, lungs. Skin allergies in some people.	Stainless steel, plumbing, engines, nickel plating, batteries.	Occupational exposure, contaminated soil or plants.
Zinc	Essential nutrient in small amounts. Large amounts can cause anemia, stomach cramps, pancreas damage, nausea.	Coatings, batteries, steel. Zinc compounds are used in paint, rubber, dyes, wood preservatives, skin creams.	Contaminated water, fish. (Zinc does not build up in plants.) Overconsumption of dietary supplements.