Dubrovsky, N., Burrow, K., Clark, G., Gronberg, J., Hamilton, P., Hitt, K. 2010. The quality of our Nation’s waters—Nutrients in the Nation’s streams and groundwater, 1992–2004. USGS Circular 1350. US Geological Survey, Sacramento, CA.

agriculture, groundwater, nutrients, pollutant, surface water, urban

The National Water Quality Assessment (NAWQA) Program of the U.S. Geological Survey conducted a comprehensive national analysis of nutrients in streams and groundwater from 1992 through 2004. Findings describe nutrient occurrence, key sources of nutrients, potential effects on humans and aquatic life, and changes in concentrations since the early 1990s.