Roz Roscoe

Results of a nationwide study on nitrates show this chemical contaminant is increasing in United States ground water sources. According to the U.S. Environmental Protection Agency (EPA), the agency regulates nitrate levels because of possible cancer risks… kidney malfunction… hemorrhaging of the spleen… and infant health concerns.

Scientists at the U.S. Geological Survey (USGS) studied nitrate trends in ground water as part of the agency’s federally funded National Water-Quality Assessment (NAWQA) Program. Study results were published in a companion supplement to the September-October issue of the Journal of Environmental Quality.

According to a statement from the American Society of Agronomy, USGS scientists studied trends in nitrate concentrations in ground water between 1988 and 2004. They collected ground water samples from 495 wells in 24 U.S. well networks, mostly in agricultural areas. Each well network was sampled once between 1988 and 1995, and re-sampled between 2000 and 2004.

The researchers found statistically significant increases in concentrations of nitrate in seven of the 24 well networks. And what’s worse, three of the seven well networks showed increases above the EPA maximum contaminant limits of 10 parts per million!

“This study highlights the importance of maintaining long-term ground-water monitoring programs in the nation, because sustained monitoring provides critical information on changes of our nation’s ground-water quality, and whether pollution prevention programs are effective in protecting this nation’s ground water,” said Michael Rupert, a hydrologist with the USGS.