Arsenic

On this page:

What is arsenic?
Ways you can be exposed to arsenic
Health effects of arsenic
Homes using private wells for drinking water and household use
Health guidelines for arsenic
Ways to avoid getting too much arsenic
Current and past uses of arsenic
Are there medical tests to see whether I have been exposed to arsenic?
Printable information sheet
Contact for more information

What is arsenic?

Arsenic is a naturally occurring substance that can be present in air, groundwater, soil, rocks, and metal ores. Arsenic has no taste or odor.  While it is not common, it is possible for high levels to occur in groundwater just about anywhere in Minnesota.

Arsenic exists in different chemical forms that are separated into two groups:
inorganic arsenic or organic arsenic.

  • Inorganic forms of arsenic are found in soil, rock, and water. Most people regularly take in tiny amounts (about 6 micrograms per day) from food and water. Large amounts of inorganic arsenic can be harmful to your health.
  • Organic forms of arsenic are generally much less harmful to people than inorganic forms, and some are considered relatively risk free. People can take in up to a few hundred micrograms each day depending on their diet.

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Ways you can be exposed to arsenic

  • drinking water
  • food
  • inhaling sawdust or smoke from wood treated with arsenic (CCA)
  • pesticides or soil supplements
  • food supplements or medications
  • animal medications
  • jobs like copper smelting or pesticide/fertilizer manufacture/application
  • swallowing small amounts of soil while playing or gardening

Arsenic in rice…

  • the FDA has tested many rice samples for arsenic
  • levels of arsenic found in rice are too low to cause immediate or short-term health effects
  • FDA advises that consumers – including pregnant women, infants, and children – can continue to eat rice as part of well-balanced diet

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Health effects of arsenic

Use of drinking water containing more than 200 micrograms of inorganic arsenic per liter over many years has been linked to problems with the skin, blood circulation, lungs, and the nervous, immune and endocrine systems. Elevated amounts of inorganic arsenic in drinking water have also been linked to higher rates of some cancers, including skin, bladder and lung cancer.

Arsenic can cause many different health problems in people, but it is difficult to predict how a specific individual will be affected. The health effects of arsenic depend on many factors:

  • the chemical form of the arsenic in the exposure
  • how a person comes into contact with the arsenic
  • how much arsenic enters and is absorbed by the body
  • the duration of the exposure
  • the health of the exposed person

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Homes using private wells for drinking water and household use

MDH strongly recommends that owners of private wells test their water for arsenic at least once. All newly constructed drinking water wells must now be tested for arsenic. Water samples should be tested by an MDH certified laboratory.

    • If no arsenic is found, further testing is usually not necessary.
    • If arsenic is measured above 10 micrograms per liter, repeat the test to confirm the result.
    • If repeat testing confirms the results, do not use the water for drinking or cooking. Other uses (e.g., bathing, laundry, dishwashing, watering gardens and plants) are okay. MDH recommends installing a treatment system at a tap used for drinking and cooking to reduce arsenic levels in water for those uses. For information on water treatment, visit the MDH Well Management webpage at www.health.state.mn.us/divs/eh/wells.
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Health guidelines for arsenic

  • For public drinking water, the Environmental Protection Agency has set a limit of 10 parts per billion of arsenic.  This amount is the same as 10 micrograms of arsenic per liter of drinking water. Arsenic in drinking water at this level or below may still be associated with some additional cancer risk.
  • Soil levels up to about 20 parts per million are generally believed to be safe.

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Ways to avoid getting too much arsenic

  • Don't burn wood that is or may be treated with arsenic. If you’re unsure, don’t burn it. You should dispose of arsenic-treated (CCA) wood in trash with other solid waste. See “Current and past uses of arsenic” below.
  • If you have a well, test the water for arsenic. There are treatment systems you can use if your water has high arsenic levels. For information on water treatment, visit the MDH Well Management webpage at www.health.state.mn.us/divs/eh/wells.
  • Know the ingredients of all medications or health remedies you use.
  • Eat a well-balanced diet from a variety of food sources. A varied diet contributes to general good health and nutrition, as well as lowers the risk of being overexposed to unwanted chemicals that may be in particular foods.
  • If you have a deck or other wood structures treated with arsenic, seal them every six months to two years.
  • If children have contact with arsenic-treated wood, such as on a play structure, make sure they wash their hands after playing and before eating.
  • Even though arsenic is generally not absorbed by plants, you should thoroughly wash and peel vegetables grown in soil because the dust or soil on the plant may contain arsenic.
  • Check old pesticides and soil supplements you have to see if they contain arsenic. If you’re not sure whether they contain arsenic, don’t use them. Arsenic-containing materials can be disposed of at Household Hazardous Waste collection sites. Contact your county to find out how to safely dispose of such items.

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Current and past uses of arsenic

Arsenic has been used in pesticides to kill weeds like Creeping Charlie and to protect crops and animals from insects. Arsenic pesticides (including unmarked containers) may be found in old barns and garages. Large amounts of arsenic were historically found in some soil supplements and fertilizers that were manufactured from mining wastes.

Poultry litter can be a significant source of arsenic released to the environment when birds are fed small amounts of organic arsenic to increase feed efficiency. Use of these supplements does not increase arsenic in meat to levels of concern or levels found in other foods. Discontinuing the use of arsenic in poultry feed is an industry trend and should lower the amount of arsenic in poultry meat and litter.  

Until its removal from the market in 2003, chromated copper arsenic (CCA) was a widely used wood preservative. CCA-treated wood was used to build houses, playgrounds, decks and other residential structures. Presently, CCA may be used for non-residential structures and in some permitted uses on farms and ranches. In addition, CCA may be present in old decks and play structures made from CCA-treated wood.

Some ethnic or alternative medications (for example: some Ayurvedic formulations) have been found to contain large amounts of arsenic. Do not use any medication that does not list its contents on the container.


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Are there medical tests to see whether I have been exposed to arsenic?

Although such tests exist, the results are often difficult to interpret.

  • Hair and fingernails can be tested to look for exposure over several months.  It is possible however, that arsenic that is found came from contamination on the outside of the hair or nail, rather than from within the body.
  • A urine test only measures exposure that occurred over the last few days. Inorganic and organic arsenic are both measured together in urine. To only measure the more harmful (inorganic) forms of arsenic in urine, you would either need to remove all seafood from your diet for a couple of weeks before the test, or ask for a special test that can tell the difference between organic (typically safe) and inorganic (harmful) arsenic.

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Printable information sheet:

Arsenic(PDF: 172KB/2 pages)

For more information, please contact us.
Updated Monday, October 27, 2014 at 02:51PM