Real estate brokers and agents need to be aware that the Environmental Protection Agency is preparing - probably for release some time this year - new drinking water standards concerning arsenic concentrations that almost certainly will become a costly headache for municipalities in the Southwest, Midwest and Northeast.

New maps published by the U.S. Geological Survey, and available on the Internet, are considered the most detailed and accurate water resource maps in history. Those maps suggest the presence of arsenic is wider spread and at higher concentrations than previously believed. Both industrial and residential real estate professionals may need to access the maps for disclosure purposes.

The current standard for arsenic contaminants in drinking water is 50 micrograms per liter (MCL). The World Health Organization, however, already has reduced the global standard to 10 MCL and some insiders believe the EPA may attempt a standard as low as 5 MCL.

The presence of arsenic in ground water is largely the result of minerals dissolving naturally over time as rock and soil weather, says the USGS.

While recognized as a toxic element for centuries, scientists now believe arsenic is an additional human health concern because it can contribute to skin, bladder and other cancers, according to the National Research Council. The Research Council is among those calling for a lower standard.

Public water systems exceeding a new, lower MCL will be required to either treat their water or find alternative sources. Either way, consumers will find water prices escalating even as their threat of exposure decreases.

Homeowners with private wells are not regulated, but adoption of a low MCL standard could put new testing burdens on agents working with potential buyers.

In the last 20 years, the USGS has collected and analyzed drinking water samples from 18,850 wells in 595 counties across the United States. These wells were used for irrigation, industrial purposes and research, as well as for public and private water supply.

Arsenic concentrations in ground water generally were highest in the West. Parts of the Midwest and Northeast also had arsenic concentrations that exceeded 10 MCL. Concentrations appear to be lower in the Southeast, but the USGS also warned that smaller amounts of data were available from that region.

Just over 13 percent of systems used water with arsenic concentrations reater than 5 MCL. Roughly 1 percent exceeded the current 50 MCL standard.

Published: June 6, 2000

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