The Mississippi River needs more federal government action if it is once again to be clean enough for fishing and swimming, scientists said on Tuesday. In a report issued by the National Research Council, the scientists called on the Environmental Protection Agency to take a more aggressive role in enforcing the Clean Water Act, which aims to make U.S. waters "fishable and swimmable."

Parts of the Mississippi, which flows 2,300 miles from Minnesota to the Gulf of Mexico, are neither. "The limited attention being given to monitoring and managing the Mississippi's water quality does not match the river's significant economic, ecological and cultural importance," said David Dzombak of Carnegie Mellon University in Pittsburgh.

Dzombak, who headed the scientific panel that wrote the report, urged the EPA to work with the 10 states that line the river as it has with those along the Chesapeake Bay, where decades of work have cut pollution and improved water quality. On the Mississippi, one key problem is pollution from so-called nonpoint sources such as chemical runoff from farms, as opposed to direct discharges from sewage treatment plants and factories, the report said.

Nutrients like nitrogen and phosphorous enter the river from fertilizer runoff, creating significant pollution in the river itself and contribute to an oxygen-deficient "dead zone" in the northern Gulf of Mexico, the scientists found.

Sediments are also a problem that affect different parts of the river differently. In the upper Mississippi, they are too plentiful and a pollutant, but near the river's mouth, sediments are scarce and their absence contributes to a loss of coastal wetlands in southern Louisiana. Continued...
(By Deborah Zabarenko, Reuters, 16/10/2007)