New Jersey Environmental Public Health Tracking Program

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Arsenic in Drinking Water

What is Arsenic?

Arsenic (As) is a naturally-occurring element in the earth’s crust, and trace amounts can be found in geologic formations, soils and groundwater in parts of New Jersey.  Arsenic may also be found in soils as a result of past use of arsenic-containing pesticides and wood preservatives.  Arsenic in drinking water is odorless, tasteless and colorless.  

How Does Arsenic Affect Human Health?

Arsenic has been classified by the U.S. Environmental Protection Agency (USEPA) as a known human carcinogen, based on human epidemiological data.  Ingestion of large amounts of inorganic arsenic is associated with increased risk of several types of cancer in humans, including skin, lung, liver, kidney and urinary bladder.  Other potential effects of ingesting large amounts of arsenic include gastrointestinal ailments, such as diarrhea and cramping, thickening and/or discoloration of the skin, and increased risk of diabetes and cardiovascular disease.

Although short-term exposures to high doses of arsenic can cause adverse effects in people, such exposures do not occur from public water supplies in the U.S. that comply with the arsenic maximum contaminant level.  Some people who drink water containing arsenic in excess of the standard could experience skin damage or problems with the circulatory system, and may have an increased risk of certain cancers.

Based on lung and bladder cancer data from epidemiologic studies, the National Academy of Sciences has estimated that the additional lifetime cancer risk associated with drinking water that contains 5 micrograms per liter (µg/L) of arsenic is about 2 cancer cases in 1,000 people. This means that if 1,000 people were to consume two liters of this water per day for 70 years, we would expect to see no more than 2 additional cancers during the lifetimes of the 1,000 people.

What is Being Done to Protect Human Health?

The New Jersey Department of Environmental Protection (NJDEP) adopted a new Maximum Contaminant Level (MCL) for arsenic of 5 µg/L, effective in January 2006.  New Jersey now has the most protective arsenic drinking water standard in the nation (the USEPA’s MCL is 10 µg/L).  NJDEP requires the more than 600 public community water systems and 900 non-transient, non-community water systems in New Jersey to monitor periodically for arsenic and to comply with the MCL.

The NJDEP Private Well Testing Act requires wells in 10 counties to be tested for arsenic at the time of property transfer and also requires landlords to test private wells and provide tenants with the results.

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