Minnesota's top pollution officials are setting ambitious goals - primarily for farmers - to cut back on the millions of tons of pollution that each year flow out of the state and down the Mississippi River to the Gulf of Mexico, where it adds to a dead zone incapable of supporting sea life.
Within 12 years, according to a plan that will be publicly released next week, the state hopes to reduce nitrogen lost from farm fields, urban streets and water treatment plants by 20 percent. Phosphorus, another nutrient that primarily comes from agricultural fertilizers and soil runoff, would be reduced by 35 percent, said Rebecca Flood, assistant commissioner at the Minnesota Pollution Control Agency.
She laid out the plan Tuesday before a group federal and state environmental regulators meeting to assess progress on fixing the gulf's 6,000-square-mile dead zone.
"Minnesota takes its role as a headwaters state very seriously," she said, pointing out that almost all the water that falls on the state in the form of rain and snow ends up in the Red and Mississippi rivers. But by the time it leaves the state, it is contaminated with nitrogen and phosphorus.
High concentrations lead to excessive plant and algae growth, and, eventually, not enough oxygen in the water to support fish and other aquatic life. Many cities throughout Minnesota and the Midwest spend millions annually to remove nitrogen from drinking water because at high levels it poses a serious health risk to infants.
About 78 percent of the nitrogen and 40 percent of the phosphorus in the state's major rivers can be traced to fertilizers used on crops, according to state researchers, even though farmers use far less per acre than they did a few decades ago. But overall, the amount applied to the land has increased along with the number of acres devoted to corn.
Minnesota is one of 12 states along the Mississippi that has agreed to devise a cleanup plan for the nutrients. Ultimately, the goal set by the Environmental Protection Agency and other states is a 45 percent reduction by 2045.
Mark Hammerlink, communications director for the Minnesota Corn Growers Association, said he could not comment on the state's plan until the group's scientists had a chance to review it.
Environmental groups say they applaud the goals but the not the strategies designed to achieve them. The EPA, Minnesota and other states say they will rely on education and voluntary actions by farmers and other landowners. Environmental groups say that without laws and enforcement, that strategy is likely to fail.
The disagreement has landed in a federal court, which last week ruled partly in favor of the Gulf Restoration Network and the Natural Resources Defense Council, environmental groups that in 2008 petitioned the EPA to take stronger action. A New Orleans federal judge gave the EPA six months to decide whether to use the federal Clean Water Act to set limits for nitrogen and phosphorous in all U.S. waterways or explain why they're not needed.
Such agricultural pollution is becoming increasingly contentious nationwide. This month, a federal judge in Virginia upheld pollution limits designed to improve the health of Chesapeake Bay by more tightly regulating wastewater treatment, construction and agricultural runoff. Similar concerns are rising around massive algae blooms in Lake Erie that have been tied to agricultural pollution in Ohio.
Flood, however, said that Minnesota will continue to rely on research, demonstration projects and persuasion to reduce nitrogen and phosphorus. In the next 12 years, she said, nitrogen from agriculture will be reduced by 19 percent if farmers choose to use the most effective management techniques and technologies. For example, increasing fertilizer use efficiency on 13.2 million acres will reduce nitrogen lost to water by 13 percent. Growing cover crops on an additional 800,000 acres will reduce it by 3 percent.
Nitrogen levels in the Mississippi have remained unchanged since 2000. The state has taken strides in reducing phosphorus, primarily by improving wastewater treatment facilities, she said. But future reductions will have to come primarily from farmers, she said.
Trevor Russel, program director for Friends of the Mississippi River, said the goals are laudatory, but changing land management practices across millions of acres will be a staggering task without funding for farmers or regulatory requirements, he said.
"It seems highly unlikely," he said.
Hammerlink said voluntary measures are a far better choice than imposing regulations on farmers. But more importantly, he said, research is needed to find the methods that will be sure to reduce the pollution from fields, and that will be worth a farmer's investment.
"You have to wait for the science to catch up with the intent," he said.
Explore further: Wetlands more cost-effective in nutrient removal, but multiple payments would be of uncertain value