No cap for nitrogen: Editorial

By Editorial page staff, The Times-Picayune
Saturday, August 07, 2010, 6:40 AM

The crude oil that fouled the Gulf of Mexico captured the nation’s attention this summer, but other pollutants — nutrients washed down the Mississippi River — arrive every year, causing a massive dead zone off Louisiana’s coast.

This summer’s area of low oxygen is 7,722 square miles, nearly the size of New Jersey. That’s twice the size of last year’s dead zone, when lower spring water levels in the Mississippi River meant less nitrogen and phosphorus washed into the Gulf. This year, high water levels in the spring and summer meant more nutrient pollution to fuel bumper crops of algae that deplete oxygen when they decompose.

The oil from BP’s well that gushed for weeks is contained, and the federal government says that only 26 percent of the oil remains. But there’s no end in sight to the pollution that pours into the Gulf of Mexico every year, and its effects are also destructive. Low oxygen levels kill bottom-dwelling marine life that is the basis of the food chain.

The Mississippi River-Gulf of Mexico Watershed Nutrient Task Force has set the goal of shrinking the average size of the dead zone to 1,900 square miles by 2015. But the task force is relying on voluntary measures to lower fertilizer use, and obviously that’s not working.

The EPA’s Office of Inspector General recommended a year ago that the agency set numerical standards for the amount of nutrients allowed in the Mississippi and other bodies of water, noting that state governments have been too slow to adopt such measures.

The report called the Gulf of Mexico and the Mississippi River "critical national waters,” and said that it is EPA’s responsibility to act if states do not.

This pollution can be curbed by using less fertilizer, creating wetlands and grassy strips along farmland to filter nutrients and reducing emissions from runoff and reduce emissions from urban sewage systems, industry and individual septic systems.

Nitrogen and phosphorus are certainly not the only pollutants that arrive in the Gulf of Mexico via the Mississippi and other rivers. Herbicides, pesticides and pharmaceuticals also flow into the Gulf. The same type of chemicals that were used to disperse the oil — and a similar amount — enter the Gulf every day, from household soaps and industrial solvents. Researchers call those substances "emerging contaminants” that may hurt marine life.

But the effects of fertilizers are already well-known and well-documented. Reducing the amount that ends up in the Gulf needs to become a more urgent national priority.