Wednesday, January 18, 2012

Trace Elements Exceed Health Standards in 20 Percent of U.S. Water Wells by Brett Walton

Nearly one in five wells in the United States contains traces of at least one element that exceeds human health standards set by the U.S. Environmental Protection Agency (EPA), according to a U.S. Geological Survey (USGS) study of more than 5,000 public, private, and monitoring wells.

When multiple elements are found in the same water source at concentrations higher than national health standards — as is the case in one in ten U.S. wells — this poses an even greater health concern, because they can interact to become even more toxic than each element would be individually. Furthermore, trace elements exceed health standards in groundwater more often than do pesticides or volatile organic compounds, such as fuels and solvents.

Public utilities are required by the Safe Drinking Water Act to treat water to standards set by the EPA. But even those systems can be out of compliance. For instance, in July, Circle of Blue reported that nearly 1,000 water utilities — most of which are small systems serving fewer than 10,000 people — remain in violation of the EPA’s standard for arsenic, a decade after the rule was first submitted.

However, the greater health risk is arguably with those individuals not connected to a public utility system, since privately owned wells do not have the same federal requirements. Private wells are not regulated at the national level, and there are only a few cases in which private wells are regulated at state and local levels. Nearly 43 million people in the U.S. supply their own water, with some 98 percent using private wells, according to estimates from the USGS in its 2005 national water use survey.

“By and large, most [private well users] are unaware of a broad group of contaminants that could be affecting their health,” said Joe Ayotte, a USGS hydrologist and the lead author of the 2011 study, in an interview with Circle of Blue.

Elements of Concern
Of the elements regulated by the EPA, the USGS study found that arsenic (in 7 percent of samples) and uranium (4 percent) were most prevalent in the wells it tested. Long-term exposure to high levels of arsenic — an element most commonly found in the Western U.S, the upper Midwest, and the Northeast — can cause cancers of the skin, bladder, and lungs, as well as skin lesions. Uranium exposure affects the kidneys.

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