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Wisconsin Department of Health Services


Also known as: Arsen, Arsenia
Chemical reference number (CAS): 07440-38-2

What is arsenic?

Arsenic is a naturally occurring mineral found in soil, bedrock, and water. In its pure form, arsenic is a silver-gray or white brittle metal. Arsenic has no odor and is almost tasteless.  Arsenic and its compounds have a variety of commercial uses. Manufacturers use arsenic to make other metals, glass, electronic components, and wood preservatives.

Arsenic occurs naturally in some Wisconsin drinking water supplies. Drugs used to treat parasite diseases have contained arsenic.

How are people exposed to arsenic?

Breathing:  Arsenic in food or water does not evaporate into the air. However, burning arsenic-containing materials such as treated lumber will put arsenic fumes into the air. Burning treated wood in a wood stove or fireplace may expose people to dangerous levels of arsenic. Tobacco smoke contains traces of arsenic.

Drinking/Eating:  Marine fish and seafood contain naturally high amounts of arsenic.  However, the arsenic in these foods is a non-toxic form called "fish arsenic." Calcium supplements made from sea shells may also contain high levels of arsenic.

Arsenic levels have been found in private drinking wells throughout Wisconsin. Homes that are near waste sites where paint, pesticides or electronic components are disposed may also have arsenic in the drinking water.  For more information on understanding your laboratory well test results, go to Arsenic in Well Water: Understanding Your Test Results (PDF, 215 KB).

Touching:  Levels of arsenic typically found in the environment are not easily absorbed.

Do standards exist for regulating arsenic?

Water:  Wisconsin drinking water standards for arsenic are set at 10 parts per billion (ppb).  If your arsenic level is more than 10 ppb, we suggest you stop using your water for drinking and food preparation.  The following table provides a general guide for the average person.

Arsenic level below 10 parts per billion (ppb)* This water is safe to drink and use for food preparation.
Arsenic level between 10 parts per billion (ppb) and 500 parts per billion (ppb)* Do not drink your water or use it to prepare foods that require a lot of water (e.g. infant formula, soups, Jell-O, rice, coffee, tea) if the arsenic level is above 10 ppb.  Washing foods and dishes in the water is safe, and is not a significant source of exposure.
Arsenic level above 500 parts per billion (ppb) Stop using your water for any use.  Do not use water even for showering, bathing, or flushing toilets.

*Because levels can change over time, annual testing is recommended.

Arsenic in water is not easily absorbed through intact skin.  Arsenic does not evaporate into the air.

Air: There is no standard for the amount of arsenic allowed in the air of homes. We use a formula to convert workplace limits to home limits. Based on the formula, we recommend levels of arsenic in the air of homes be no higher than 0.004 parts per million (ppm).

The Wisconsin Department of Natural Resources regulates the amount of arsenic that can be released by industries.

How can arsenic affect my health?

Your health risks are determined by the following factors:

  • the amount of arsenic in your water,
  • the amount of water you drink each day,
  • the number of years you drink the water, and
  • your individual sensitivity to arsenic.

Long-term exposure to toxic forms of arsenic may cause the following illnesses:

Cancer: Arsenic has been associated with certain types of skin cancer. Some studies also show a possible link with lung, bladder, liver, colon, and kidney cancers.

Reproductive Effects: No reproductive effects have been reported.

Skin: Very high exposure to arsenic can cause noticeable changes to skin and nails.  Arsenic exposure can cause a certain pattern of skin changes that resemble warts, called "hyperkeratosis."  Fingernails may show ridges and yellowing.  Dark or light spots may also appear.  Consult your physician if you have any health problems that you think may be caused by arsenic exposure.

Nervous System: Arsenic is harmful to the nervous system. Symptoms of arsenic exposure include tremors, headaches, and numbness.

Other health effects may include blood vessel damage, high blood pressure, anemia, stomach upsets, and diabetes.

In general, chemicals affect the same organ systems in all people who are exposed. However, the seriousness of the effects may vary from person to person. A person's reaction depends on several things, including individual health, heredity, previous exposure to chemicals including medicines, and personal habits such as smoking or drinking.

It is also important to consider the length of exposure to the chemical; the amount of chemical exposure; and whether the chemical was inhaled, touched, or eaten.

Are there special concerns about children's health?

Yes.  Prenatal and early childhood exposures to arsenic can increase the risk of lung cancer and respiratory disease in later life.  Arsenic exposure has also been associated with lower IQ scores in school-aged children and can affect learning.  The current standard is intended to protect the developing fetus and young children from these effects.

Can a medical test determine exposure to arsenic?

Urine can be tested for arsenic up to a week after the exposure. Arsenic can also be measured in hair and fingernails within a few months of exposure. The results of arsenic urine tests may be misleading if you have eaten seafood, marine fish or ocean-derived vitamin supplements in the past five days.

If a person suspects high arsenic exposure, tests that monitor the functioning of the liver and kidneys should be done. These tests can be done by a doctor on blood samples.

Seek medical advice if you have any symptoms that you think may be related to chemical exposure.

(P-44587  Revised 8/2012)

This fact sheet summarizes information about this chemical and is not a complete listing of all possible effects. It does not refer to work exposure or emergency situations.

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Last Revised:  August 28, 2014