Arsenic is usually found
in the environment combined with other elements such as oxygen,
chlorine, and sulfur (inorganic arsenic); or combined with carbon and
hydrogen (organic arsenic). Organic forms are usually less harmful than
inorganic forms.
Low
levels of arsenic are naturally present in water, about two parts arsenic
per billion parts water (ppb). Thus, you normally take in small amounts
of arsenic in the water you drink. Some areas of the country have
unusually high levels of arsenic in rock which can lead to unusually
high levels of arsenic in water.
While
your drinking water meets the U.S. EPA's standards for arsenic, it does
contain low levels of arsenic. The U.S. EPA's standard balances the
current understanding of arsenic's possible health effects against the
cost of removing arsenic from drinking water. The U.S. EPA continues to
research the health effects of low levels of arsenic, which is a
chemical know to cause cancer in humans at high concentrations and is
linked to other health effects such as skin damage and circulatory
problems.
In January 2001, the
U.S. EPA lowered the arsenic Maximum Contaminant Level (MCL) from 50 ppb
to 10 ppb in response to new and compelling research linking high
arsenic levels in drinking water with certain forms of cancer. All water
utilities are required to implement this new MCL starting in 2006. For a
more complete discussion visit the U.S. EPA's arsenic Web Site at
www.epa.gov/safewater/arsenic.html.
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