Nutrient pollution in the form of excess nitrogen and phosphorus inputs is a well-known cause of water-quality degradation that has affected water bodies across the Nation throughout the 20th century. The recognition of excess nutrients as pollution devel
Stets, Edward G.,Kelly, Valerie J. vjkelly@usgs.gov,Broussard, Whitney P. III,et al. Century-scale perspective on water quality in selected river basins of the conterminous United States. 2012-01-01.