ABSTRACT
High rates of nitrogen input to rivers and coastal waters are not confined to Europe. In an average year, the Mississippi River discharges 1.57 million metric tons of nitrogen into the Gulf of Mexico.[5] About 7 million metric tons of nitrogen in commercial fertilizers are applied annually in the basin leading to nitrate concentrations in agricultural drains of 20-40 mg/L or more.[5] In the United States, in 1998, more than onethird of all river miles, lakes (excluding the Great Lakes), and estuaries did not support the uses for which they were designated under the Clean Water Act.[6] Table 1 illustrates N inputs to rivers and coasts in areas of America, Africa, and Asia.
