While nitrogen and phosphorus levels were previously an issue in groundwater systems, and many steps have been taken, and money spent to attempt to address this issue, a recently released study by the USGS shows that these levels have stayed the same or even risen since the 1990's. Some streams contain levels two to ten times higher than what is recommended by the EPA's Water Quality Standards. Areas affected most nationally include the Northeast, Midwest, and Northwest due to high use of fertilizer and manure for agricultural purposes.
Beside threatening aquaculture in these streams, drinking water with high nitrate levels is also a concern for humans. Aquifers and shallow wells are at risk and the potential for these nitrate levels to rise in the next few years as groundwater high in nutrient concentration penetrates the soil. Since private wells are not under the jurisdiction of the Federal Safe Drinking Water Act, homeowners should test their water annually to make sure that it is safe.
The USGS's fact sheet for Nutrients in the Nation’s Streams and Groundwater gives a detailed analysis of the study's findings. For further reading suggestions, see our recommended reading list on drinking water quality.
Photo courtesy of Roger Wendell.