Arsenic is a naturally occurring element found in the environment, especially in food and water. However, exposure to high levels of the inorganic form, such as that found in wood preservatives, insecticides, and weed killers, can be deadly. Known for its role in poisonings, arsenic can be inhaled or ingested, or, to a lesser degree, absorbed through the skin. Arsenic targets the central nervous system, causing convulsions and death. As little as one-tenth of a gram accumulated over a two-month period can produce death, and arsenic is carcinogenic at much lower levels.
Studies have linked long-term arsenic exposure in drinking water to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate, according to the U.S. Environmental Protection Agency. It is also associated with cardiovascular, pulmonary, immunologic, neurological, and endocrine problems.
Arsenic can enter the water supply from natural deposits in the earth or from industrial and agricultural pollution. It is used for a variety of purposes within industry and agriculture, and is a by-product of copper smelting, mining, and coal burning. Industries in the United States release thousands of pounds of arsenic into the environment every year.
Arsenic toxicity can contribute to a wide array of symptoms and conditions, including, but limited to:
- Cardiac disease, lung disease, diabetes, and diseases of the blood vessels
- Damage to the liver and kidneys (causing jaundice and fluid loss or fluid retention)
- Difficulty healing from injury
- Electrolyte imbalances or depletion
- Hair loss
- Hyperpigmentation (darkening) of the skin and vitiligo (white patches)
- Increased risk for cancer of the bladder, lung, kidney, liver, and colon, and prostate
- Iodine and folic acid deficiencies that damage the thyroid (resulting in goiters)
- Skin problems, including skin cancer
Common sources of arsenic exposure include:
- Fungicides, herbicides, insecticides, and pesticides
- Water (polluted by runoff from pesticides, natural mineral deposits, industrial disposal)
- Wood preservatives
Shellfish in particular can accumulate arsenic—an organic form called arsenobetaine that is less harmful—and should be eaten selectively and sparingly or avoided completely.