U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska

 

Document Type

Article

Date of this Version

2008

Comments

Published in Nitrogen in the Environment: Sources, Problems, and Management, Second edition, ed. J. L. Hatfield & R. F. Follett (Amsterdam, Boston, et al.: Academic Press/Elsevier, 2008).

“Copyright protection is not available for any work prepared by an officer or employee of the United States Government as part of that person's official duties.”
United States Code, Title 17, §105.

Abstract

A recent report to Congress concerning water quality in the United States indicated that 35%, 45%,and 44'% of the assessed rivers and streams, lakes, and estuaries, respectively, were impaired by one or more pollutants (US Environmental Protection Agency, 1999). Nutrients, primarily nitrogen (N) and phosphorus (P), contributed to the impairment of 30% or 135,000 km of the nation's impaired rivers and streams. 44% of the impaired lakes, and 23% of the impaired estuaries. Excessive nutrient loads are implicated in the eutrophication of lakes and reservoirs in the United States and coastal ecosystems where N is most limiting to primary productivity (Vitousek et al., 1997; Carpenter et al., 1998). Efforts arc currently underway to establish Total Maximum Daily Load (TMDL) values for pollutants, including nutrients, of impaired water bodies as described under Section 303(d) of the Clean Water Act of 1972.

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