What other national studies assess biological communities related to nutrients?
Yes, the U.S. Environmental Protection Agency (USEPA) conducted an assessment of wadeable streams and rivers that account for a vast majority of the length of flowing waters in the United States. The USEPA, along with states, and tribes collected chemical, physical, and biological data at 1,392 randomly selected wadeable stream sites nationwide. This study reported that 30 percent of the streams in the conterminous United States contained impaired biological communities and identified nitrogen and phosphorus as the leading causes of impairment (USEPA, 2006). For more information on this study go to Wadeable Streams Assessment web site. http://www.epa.gov/owow/streamsurvey/ In addition, national aquatic resource surveys are available through EPA at: .
