Most Arsenic Presumed to be From Naturally Occurring Sources
A new study by the U.S. Geological Survey and Centers for Disease Control and Prevention estimates about 2.1 million people in the U.S. may be getting their drinking water from private domestic wells considered to have high concentrations of arsenic, presumed to be from natural sources.
“About 44 million people in the lower 48 states use water from domestic wells,” said Joe Ayotte, a USGS hydrologist and lead author of the study. “While we’re confident our research will help well owners understand if they live in an area of higher risk for arsenic, the only way for them to be certain of what’s in their water is to have it tested.”
Using a standard of 10 micrograms of arsenic per liter -- the maximum contaminant level allowed for public water supplies -- the researchers developed maps of the contiguous U.S. showing locations where there are likely higher levels of arsenic in groundwater, and how many people may be using it.
Nearly all of the arsenic in the groundwater tested for this study and used to map probabilities is likely from natural sources, and is presumed to be coming primarily from rocks and minerals through which the water flows.
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