Is arsenic in drinking water harmful?


Long-term exposure to arsenic in drinking water is associated with multiple health problems.

  • Arsenic is a known human carcinogen linked to cancers of the skin, bladder, kidney, liver, and lung.
  • Arsenic has been shown to cause vascular disease (loss of circulation in the limbs) and skin abnormalities (changes in skin texture and color).
  • Some researchers have found evidence that arsenic can disrupt the immune and endocrine systems, and may be related to Type-2 diabetes.
Drinking water is the main source of human exposure to arsenic. more

Seafood also contains arsenic, but it is “organic” arsenic, which is much less toxic than “inorganic” arsenic—the type found in water.

For drinking water, the health standard for arsenic in water is 10 micrograms per liter (ug/L), which is equivalent to 10 ppb (10 parts of arsenic per 1 billion parts of water). more

This is the USEPA Maximum Contaminant Level (MCL) for arsenic, a national standard for public-water systems. The  Ohio Department of Health has adopted the same standard for household wells and other private water systems.

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