The study released Tuesday by the National Research Council calls on the Environmental Protection Agency to coordinate the efforts affecting the river and the northern Gulf of Mexico where its water is discharged.
"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 A. Dzombak, professor of environmental engineering at Carnegie Mellon University in Pittsburgh.
Dzombak, who was chairman of the committee that prepared the report, said that "in addressing water-quality problems in the river, EPA and the states should draw upon the useful experience in the Chesapeake Bay watershed, where for decades the agency has been working together with states surrounding the bay to reduce nutrient pollution and improve water quality."
Because it passes through or borders many states, the river's quality is not consistently monitored, the report said.
In the north, the Upper Mississippi River Basin Association has promoted many cooperative water-quality studies and other initiatives, the report said. That group includes Illinois, Iowa, Minnesota, Missouri and Wisconsin.
But there is no similar organization for the lower-river states -- Kentucky, Tennessee, Arkansas, Mississippi and Louisiana -- and they should strive to create one, the report said.
EPA also should support better coordination among states, and among its four regional offices along the river corridor, the report says.
Greater effort is needed to ensure that the river is monitored and evaluated as a single system, said the report.
While the 10 states along the river conduct their own programs to monitor water quality, state resources vary widely and there is no single program that oversees the entire river.
In recent years, actions have reduced much point-source pollution, such as direct discharges from factories and wastewater treatment plants.
But the report notes that many of the river's remaining pollution problems stem from nonpoint sources, such as nutrients and sediments that enter the river and its tributaries through runoff.
Nutrients from fertilizers create water-quality problems in the river itself and contribute to an oxygen-deficient "dead zone" in the northern Gulf of Mexico.
The National Research Council is an arm of the National Academy of Sciences, an independent organization chartered by Congress to advise the government on scientific matters. Randolph E. Schmid