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NH Environmental Public Health Tracking Program

Arsenic and Your Health

Arsenic is a toxic chemical element that is found in the Earth's crust in soil, rocks, and minerals. The levels of arsenic found in drinking water systems and private water supplies across the United States vary widely. Arsenic occurs naturally in the environment and as a by-product of some agricultural and industrial activities. It can enter drinking water through the ground or as run-off into surface water sources. There is wide variation in the levels of arsenic found in community and private water systems in NH.

Some people who drink water containing arsenic in excess of the U.S. Environmental Protection Agency's (EPA) standard over many years could experience skin damage or problems with their circulatory system and may have an increased risk of developing cancer.

In 2001, the U.S. Environmental Protection Agency (EPA) reduced the regulatory drinking water standard (maximum contaminant level or MCL) from 50 parts per billion (ppb) to 10 ppb on the basis of bladder and lung cancer risks. Lowering the MCL reduces bladder and lung cancer mortality and morbidity by 37-56 cancers a year in the U.S.

Exposure and Risk

The majority of health risks of arsenic exposure in the United States are long term. Although short-term exposures to high doses cause adverse effects in people, such exposures do not occur from U.S. Environmental Protection Agency (EPA)-regulated public water supplies in the United States that comply with the arsenic Maximum Contaminant Level. A high dose is about a thousand times higher than the drinking water standard.

Some people who drink water containing arsenic in excess of EPA's standard over many years could experience health effects, including:

Reduce Your Risk

All community water systems are required to monitor for arsenic at the entry-point to the distribution system. However, the frequency of monitoring varies based on source water type and the level of arsenic observed in past samples because some systems have little potential for arsenic contamination.  Routine required monitoring is performed annually for surface water and once every 3 years for ground water, with quarterly monitoring once a sample exceeds 10 ppb. With a state granted monitoring waiver the sampling frequency can be reduced to once every 9 years.

If your water comes from a municipal or privately-owned water company that meets the definition of a community water system, your water is already tested for arsenic. Your water provider should notify you of any violations or actions you may need to take. If you have any questions, contact your water provider.

If you have your own household water supply, you are responsible for maintaining and testing it. Contact your local health department to find out whether arsenic is a contaminant of concern in your area. NH Department of Environmental Services can give you names of laboratories that are certified to test drinking water.

For more information on arsenic:

For more information on monitoring requirements and the arsenic rule:

To find certified home treatment units:

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Environmental Public Health Tracking Program
NH Department of Health and Human Services, Division of Public Health Services
29 Hazen Drive, Concord, NH 03301
Tel: (603) 271-4988 800-852-3345 ext.4988

copyright 2009. State of New Hampshire