Arsenic in Drinking Water: Measures and Data
Why is Arsenic a concern?Arsenic exposures from human and natural causes can accumulate to unhealthy levels. Prolonged exposure may lead to cancer, cardiovascular disease, developmental and reproductive abnormalities, changes to the skin, and other organ system damage. Drinking water exposure can occur from both groundwater and surface water, although groundwater is the more likely source type. Although some counties in Washington require testing for arsenic in private wells (non-state-regulated), most do not.
How is it tracked?Water systems routinely test for arsenic after the water is treated. EPA’s maximum contaminant level (MCL) became more stringent in 2002; water systems had to adjust to the change by early 2006. Arsenic levels are tested at various times within a 3-year compliance period, and MCLs are based on a running annual average of samples.
What can be done about elevated arsenic levels?Avoiding water with high arsenic content and avoiding building with pressure-treated wood can reduce exposure. Point-of-use or whole-house systems can be installed in homes to eliminate arsenic specifically. Consumer testing can verify whether the installed system works properly. If bottled water is used, care should be taken to make sure the manufacturer tests for arsenic.
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