Guardian Environmental Network
Gulf dead zone
Each year a group of scientists sets out to measure the dead zone — an area where oxygen has been so depleted that it can’t support life — in the Gulf of Mexico. Last year, it had grown to the size of Massachusetts. On Tuesday, in an attempt to stop it from reaching the size of Michigan or Texas or even Alaska, environmental groups filed two lawsuits aimed at forcing the EPA to reduce the pollution that creates the dead zone — pollution whose main source is human and agricultural waste carried down the Mississippi River from the nation’s Farm Belt and cities like Chicago.
Currently the EPA doesn’t require wastewater treatment plants to filter out nutrients such as nitrogen and phosphorous — even though those nutrients are a large part of what’s choking the Gulf. The agency hasn’t set wastewater treatment guidelines since 1985, when the technology to remove nutrients was extremely expensive. It’s gotten cheaper, environmental experts say, and EPA needs to change its guidelines appropriately. “We believe that the technology exists and is affordable,” said Andrew Rota, director of science and water policy at the Gulf Restoration Network in a press conference.
The plaintiffs, including the Natural Resources Defense Council (which publishes OnEarth), also want EPA regulators to set national rules for nutrient runoff from agriculture. Right now, states are left to set those guidelines themselves, but few really are, said Glynnis Collins, executive director of the Prairie Rivers Network. Of the ten states that flank the Mississippi, “only Wisconsin and Minnesota have taken action towards the problem,” Collins said.
EPA declined to comment on the lawsuit.
Over the past fifty years, the dead zone has tripled in size, due to increased human development and agriculture along the rivers that flow into the Gulf, according to a report released last year. Nitrogen and phosphorous provide food for algae, which consumes oxygen in the water and creates the region that can’t support other forms of life, including fish and shrimp. (Good luck dropping a net into the area devoid of oxygen.) Gulf beaches are forced to close each year due to toxic algal blooms, and wildlife is put at risk — in 2004, 107 bottle-nosed dolphins died after an encounter with toxic algae. Nitrogen and phosphorous also degrade the soil quality along the banks of the Mississippi and its tributaries, leaving low-lying areas prone to destruction during hurricanes.
“The Mississippi River and the entire Gulf has been treated as the nation’s sewer for decades,” Rota said. “It’s long past time for the EPA to start addressing the dead zone.”
Although the Gulf zone may be the largest and most famous in U.S. waters, it’s not the only one. Other bodies of water, including the Great Lakes, are seeing growing dead zones due to nutrient pollution, as OnEarth explored last year in the story, “Lake Erie Death Watch.” As NRDC’s Thom Cmar writes, Wednesday’s lawsuit could help address the problems there, too.
Image: Mississippi River plume meets Gulf of Mexico water at Southwest Pass, a primary shipping channel in Louisiana waters (N. Rabelais courtesy USGS)