Nitrogen and Phosphorus Pollution Series: Nitrate in Ground Water
April 29, 2011
- Audrey Eldridge, Coordinator for the Southern Willamette Valley Groundwater Management Area, Oregon Department of Environmental Quality
- Jill Jonas, Director, Bureau of Drinking Water and Groundwater, Wisconsin Department of Natural Resources
- Neil M. Dubrovsky, PhD, Chief, Nutrients and Trace Elements National Synthesis Project, National Water Quality Assessment (NAWQA), U.S. Geological Survey
This webcast will highlight an emerging issue of increased nitrate loading to ground water, a growing national concern. According to EPA’s most recent data, public water systems using ground water as a drinking source serve over 300 million people nationwide. The total number of people drinking ground water increases when factoring in households supplied by private drinking water wells. Ground water can become contaminated by nutrients (nitrogen and phosphorous) leaching from the land surface into the ground water supply. In a September 2010 report, Nutrients in the Nation’s Streams and Groundwater, the U.S. Geological Survey monitored and documented nitrate levels above 10 mg/L, which is the Maximum Contaminant Level (MCL) set by the National Primary Drinking Water Regulations through the Safe Drinking Water Act, in over 20 percent of shallow household wells in agricultural areas. Additionally, from 1998 to 2008, the number of nitrate violations recorded at public water systems around the country has nearly doubled. Surface sources of drinking water are also at risk as, for example, stormwater runoff can carry nutrients directly to rivers, lakes and reservoirs – some of which are used as drinking water supplies. Capital costs to remove nitrates from public water systems or to provide alternative water supplies for individual households can be very high, with some communities spending millions of dollars. The webcast will provide a national overview of the nitrate in ground water issue and highlight a case study in Oregon’s Southern Willamette Valley.