Citing new science, the state agency charged with keeping Minnesota's water clean announced Tuesday that it wants to move away from a law that's been on the books more than 40 years.
At issue is a limit on sulfate — the water quality standard designed to protect wild rice. The Minnesota Pollution Control Agency says using the same limit for every river or lake where wild rice grows doesn't make sense, because many factors influence whether wild rice will thrive.
A biologist named John Moyle sampled lakes and rivers throughout the state in the 1930s and '40s. He found that wild rice doesn't grow well when the water has high concentrations of sulfate. Sulfate is a compound that occurs naturally, but it's also released by iron mining operations and wastewater treatment plants.
Wild rice has long been a part of Minnesota's heritage, and it's especially important to Native Americans. So in 1973 the state developed a rule that limits the amount of sulfate in waters where wild rice grows. The limit is 10 milligrams per liter, which translates to roughly 7 gallons in an Olympic-sized swimming pool. Now, the Minnesota Pollution Control Agency wants to change that.
"The 10 [milligram limit] wasn't wrong," said Rebecca Flood, assistant commissioner of the MPCA. "It's just imprecise."
Sulfate itself doesn't kill wild rice. But when it mixes with the bacteria found in the muck at the bottom of lakes and rivers, it's converted into something that is toxic to wild rice: sulfide. And recent research has shown the approximate maximum levels of sulfide that wild rice can tolerate.
But MPCA officials say predicting the sulfide level isn't as simple as looking at how much sulfate is in the water. Wild rice appears to grow just fine in some waters that have high sulfate concentrations. They say iron is a factor. So is organic carbon.
Shannon Lotthammer, who directs the environmental analysis and outcomes division at the MPCA, said the agency is proposing a formula to predict whether wild rice will be able to thrive in a given lake or river.
"The available data we have just don't show a general pattern of iron and organic carbon in water bodies in Minnesota," she said. "They're very independently variable. That's why that science led us to this proposed approach of an equation and using specific information from each site to then calculate what the protective level of sulfate would be."
Those proposed sulfate values have been calculated for only a handful of lakes, but Lotthammer said the sulfate concentrations could vary from less than 1 milligram per liter to 140 milligrams per liter.
It was clear Tuesday that, although the MPCA said it was basing its proposed new standards on science, politicians were also playing a part. One indication was the timing: MPCA officials accelerated their announcement after Gov. Mark Dayton described the current standard as outdated and potentially catastrophic for mining in northeastern Minnesota.
"I'm standing up to what I think is best for Minnesota," he said. "And the standard that's antiquated, that's not even based on current science directly related to the conditions we're trying to deal with, to me doesn't make any sense."
Dayton has been actively involved in discussions about regulating pollution from taconite plants. Over the past several months, he has spoken about it with U.S. Steel executives, Sens. Amy Klobuchar and Al Franken, U.S. Rep. Rick Nolan, the Environmental Protection Agency and state legislators from the Iron Range.
But the MPCA's Flood said her agency's scientists didn't develop the standards as a result of pressure from Dayton or anyone else.
"This is something that we've been working on for years now," she said. "This is a part of our normal way of operating in developing normal water quality standards."
But the agency was getting it from all sides. State lawmakers who worried about mining and wastewater treatment plants were pushing legislation that would undermine the current sulfate standard. Rep. Jason Metsa, DFL-Virginia, called the MPCA's announcement a step in the right direction.
"On a statewide level, this has a broad impact and it's time to just find a solution that's reasonable to everyone," he said.
Senate Majority Leader Tom Bakk, DFL-Cook, said he'll continue to pursue legislation that prevents the MPCA from enforcing the current standard. It hasn't been enforced widely, and he blamed environmental groups for attempts to enforce it now. He said their push to more closely regulate the taconite operations is an indirect attempt to block future copper/nickel mining in the state.
"The crux of it is they just don't want any additional mining in Minnesota," Bakk said.
Environmental groups said the issue has less to do with new mining and more to do with enforcing the clean water laws already on the books.
Moving from a uniform standard for every body of water in the state to a formula for individual bodies of water could create openings for political pressure, said Kathryn Hoffman of the Minnesota Center for Environmental Advocacy.
"You have introduced a lot of uncertainty that is vulnerable to politics," she said.
U.S. Steel, which owns two taconite plants on Minnesota's Iron Range that are affected by the sulfate standard, praised state officials for reviewing it.
John Pastor, a scientist at the University of Minnesota Duluth who researched the relationship between wild rice and sulfate for the MPCA, said concentrations could have different effects on wild rice from lake to lake. He said the agency is right to scrutinize the level of sulfide.
But he said the MPCA's proposed formula isn't close to being the solution.
"That equation at this point is just a hypothesis," he said. "The onus is on them to show it could work. They have not done that here."
Some environmental groups were asking what would happen while the new proposal is being studied.
Attorney Paula Maccabee, representing the group WaterLegacy, which has pressured the MPCA to enforce the existing standard, said the MPCA proposal didn't mean the current limit can be ignored.
"The law is clear," she said. "We have a 10-milligrams-per-liter sulfate standard. What's going to happen in rulemaking — hard to predict. But what shouldn't be hard to predict is that what happens now is enforcing our existing rule."
The MPCA said it will seek comments from researchers and others. Once it comes up with a formal rule, which is expected in late summer, it will initiate a two-year administrative process that allows for plenty of public input before the rule becomes final.
MPCA officials said they've briefed federal officials on their proposal but couldn't say whether the existing standard will be enforced in the meantime.
U.S. Rep. Betty McCollum, D-Minn., wrote a letter to EPA Administrator Gina McCarthy earlier this month warning her not to support any efforts to weaken water quality standards in Minnesota.
A spokesman for McCollum said she would have serious concerns about any proposal that would put Minnesota wild rice at risk.
Timeline: Wild rice regulations in Minnesota
1930s and '40s: Biologist John Moyle, working for the Minnesota Department of Conservation, finds that no large wild rice stands grow in waters high in sulfate.
1973: State adopts a sulfate standard limit of 10 milligrams per liter to be discharged in waters that produce wild rice. The standard affects mining operations, industrial facilities and municipal wastewater treatment plants. The standard receives U.S. Environmental Protection Agency approval.
2008: The Minnesota Department of Natural Resources publishes a study identifying more than 1,200 bodies of water where wild rice grows.
February 2010: The EPA says Minnesota regulators must ensure PolyMet Mining's proposed copper-nickel mine meets the state's sulfate standard. That raises questions about to what extent the Minnesota Pollution Control Agency is enforcing the standard for existing iron mines.
2010: The MPCA begins asking mining companies to document wild rice plants in lakes and streams where they discharge wastewater.
December 2010: The Minnesota Chamber of Commerce sues the state to overturn the state sulfate standard. The case is eventually dismissed but the Legislature starts taking action.
July 2011: Gov. Mark Dayton signs environment bill that includes a provision requiring the MPCA to do research on wild rice and complete rulemaking. The legislation provides $1.5 million for the wild rice study. Study results won't be released for another three years.
August 2011: U.S. Steel and MPCA strike a deal to clean up Minntac and limit pollution at Keetac, including a plan to reduce sulfate discharge.
May 2012: Ramsey County District Court upholds the state's 10 milligram standard after the Chamber of Commerce sues.
November 2012: MPCA announces it will begin listing waters around the state as impaired based on inability to sustain wild rice.
January 2014: Wild rice study is completed, but MPCA officials decide to hold back on releasing recommendations on what to do with the state's current sulfate standard, saying it's complicated. A peer review panel will be called to evaluate the study.
Feb. 26, 2014: Iron Range lawmakers meet with MPCA Commissioner John Linc Stine about upcoming wild rice sulfate standard after reading news media reports about it.
March 2014: The MPCA says wild rice study confirms that sulfate affects wild rice but in complex ways, says it needs more time to determine what state's standards should look like.
October 2014: Peer review panel called on by the MPCA to evaluate the wild rice study says the work is scientifically valid, and MPCA officials continue work on policy recommendations for the state's sulfate standard.
December 2014: The EPA sends a letter to the MPCA saying U.S. Steel's draft revised Minntac permit has problems. The Minntac facility has long exceeded the state's sulfate standard.
February 2015: Several bills are introduced in the Legislature to prevent the MPCA from enforcing any sulfate standard for wild rice until rulemaking process is complete, including designating wild rice waters. House committee hears testimony from the MPCA and tribal leaders. The MPCA delays the release of Minntac's revised permit until it has announced a new approach to sulfate regulation in wild rice waters.
March 23, 2015: Gov. Mark Dayton tells MPR News the state's existing sulfate standard is outdated and will hurt mining operations in the state.
March 24, 2015: The MPCA announces a "new approach" to protecting the state's wild rice waters that uses a formula to calculate sulfate limits for each of the 1,300 lakes and rivers identified as wild rice waters.