NASA file
This 1999 NASA satellite image shows effluents deposited at the Mississippi River delta. Those deposits include topsoil as well as farm fertilizer runoff, which depletes the surrounding water of oxygen. staff and news service reports
updated 10/16/2007 10:57:08 AM ET 2007-10-16T14:57:08

States and the federal government are not doing enough to monitor and manage the water quality of the Mississippi River and its impact on the Gulf of Mexico, where an annual "dead zone" from farm runoff is killing marine life, according to a major scientific assessment released Tuesday.

The study by experts with 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 Dzombak, chairman of panel and professor of environmental engineering at Carnegie Mellon University in Pittsburgh.

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.

Dealing with the 'dead zone'
Nutrients from fertilizers create water-quality problems in the river itself and contribute to an annual oxygen-deficient “dead zone” in the northern Gulf of Mexico.

The zone grew this summer to 7,900 square miles — one of the three largest since measurements began in 1985.

Centered at the end of the Mississippi River system, the zone is one of the largest areas of oxygen-depleted coastal waters in the world.

Low oxygen, or hypoxia, can be caused by pollution from farm fertilizer, soil erosion and discharge from sewage treatment plants, according to the U.S. Geological Survey.

Excess nutrients can spur the growth of algae, and when the algae die, their decay consumes oxygen faster than it can be brought down from the surface. As a result, fish, shrimp and crabs can be forced to move or die.

Eugene Turner, a professor of oceanography and coastal sciences at Louisiana State University, said it’s tough to determine whether fish are dying because of hypoxia or other factors, such as climatic effects. However, “we really don’t want to mess with this, to make it worse,” he said.

The dead zone usually begins forming in the spring and stays through summer and into the fall. Though the size of the dead zone has shrunk some years, on average it has steadily grown larger, Turner said.

Inconsistent monitoring
The new report found that because the Mississippi River passes through or borders many states, the river’s quality is not consistently monitored.

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.

Dzombak 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.”

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.

The study was sponsored by the McKnight Foundation of Minneapolis.

The Associated Press contributed to this report.


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