Wild rice-sulfate studies concludeResults of two years of field and laboratory work on how sulfate affects wild rice were released Tuesday, but any decision on the state’s wild rice standard and its effect on the mining industry is still many months away.
By: John Myers, Duluth News Tribune
Results of two years of field and laboratory work on how sulfate affects wild rice were released Tuesday, but any decision on the state’s wild rice standard and its effect on the mining industry is still many months away.
The data was collected by studying wild rice in outdoor tubs and indoor labs at the University of Minnesota Duluth and by University of Minnesota, Twin Cities, campus scientists studying wild rice in rivers and lakes statewide.
The $1.5 million effort concluded in December, and preliminary results made public Tuesday appear to show that sulfate at certain levels does indeed affect wild rice, as suspected.
But it’s not a direct, toxic effect, said John Pastor, the lead UMD scientist on the project.
“Sulfate on its own did not have a detrimental effect on wild rice; it wasn’t directly toxic to wild rice,” Pastor said. “But when sulfate is converted to sulfides, that’s what has an effect.”
That conversion happens in the sediment as the plant tries to pick up nutrients, Pastor said.
Once sulfate is converted to sulfide “the issue is not with germination. The seeds germinate. But it adversely impacts the growth of the seedling,” Pastor said. Where sulfate wasn’t converted to sulfide, wild rice generally wasn’t damaged, he said.
The laboratory work corroborated the field work, Pastor noted, and all of it corroborated work done in the 1940s by a state scientist — John Moyle — who found wild rice did not grow well in water high in sulfate.
“Moyle made the correlation correctly. What he didn’t know is how it happened,” Pastor said. “Now, we know a lot more about how it happens.”
But knowing how it happens is different from deciding how much sulfate is too much for wild rice, and what limit to apply to industrial discharges, especially mining.
“I can’t make that recommendation. I can’t say what the limit should be,” Pastor said.
That will be up to the Minnesota Pollution Control Agency. PCA officials will take the study results and use them to help make a decision on what, if anything, to do with the state’s current standard of 10 parts per million sulfate in waters that hold wild rice stands.
For the next few months PCA staff will “analyze the data as a whole, and review existing monitoring data” and other relevant scientific studies, and by April decide whether the standard should be changed.
If the answer is yes, the PCA would come up with a proposed new standard and kick off a months-long rulemaking process that would include public input, testimony and hearings headed by an administrative law judge, all under the watchful eye of the federal Environmental Protection Agency.
Several Minnesota taconite operations are in violation of the state’s 10 parts per million sulfate limit and are waiting for the state’s decision. The PCA is getting input and guidance from a 32-person advisory committee representing taconite companies, business groups, environmentalists, Indian resource agencies and research universities.
Shannon Lotthammer, director of the PCA’s Environmental Analysis and Outcomes Division, said Tuesday that it’s “just too soon to draw any general conclusions from the data about the impact of sulfate on wild rice,” saying additional analysis is needed.
The study results “include information about the concentrations of sulfate or sulfide at which effects on wild rice were observed, and we continue to see correlations in the field data regarding sulfate and sulfide concentrations and wild rice presence,” Lotthammer said. “With that said, we need to review the results … complete our own statistical analyses, and compare the results across the individual study components before we are in a position to say anything about the general consensus or conclusions about what impact sulfate has on wild rice.”
Sulfates are ions that can come from decaying plants and animals as well as some industrial processes such as mine discharges, mine stockpiles and waste piles, tanneries, steel mills, pulp mills, sewage-treatment plants and textile plants. High sulfate levels are known to damage plants, in some cases by limiting uptake of nutrients.
The PCA is under pressure from business and mining groups to relax the standard, noting several taconite mines and other industries may not be able to meet it without huge investments that might affect Minnesota jobs.
It’s also suspected that runoff from proposed copper mining operations will be high in sulfate and that the standard could affect future mining projects. The proposed PolyMet copper mine, for example, can meet the existing sulfate standard, an environmental review concludes, but only by treating water that leaves the site for decades, possibly centuries to come.
Environment and tribal groups want to keep the old standard, saying higher sulfate standards could decimate wild rice beds and may cause other harmful environmental effects.
Minnesota lawmakers tried, on their own, to relax the state sulfate rule in 2011 in an effort to help industry. But the EPA said they could not change a law tied to the Clean Water Act without scientific backing. So the Legislature also approved money for what became the state’s largest study of wild rice.
The current standard of 10 parts per million was upheld in December 2012 by a state court of appeals ruling. The original lawsuit was filed by the Minnesota Chamber of Commerce in 2010 asking the court to throw out the state’s 1973 sulfate rule, claiming it was unfounded, based on poor science and was overly restrictive, especially for the state’s mining industry.
The court ruled that the Chamber would have to wait for the study to conclude and the state to determine any new standard.
While the state-funded study is over, Pastor said his efforts have received a $200,000 SeaGrant grant and another $60,000 from the Fond du Lac Band of Ojibwe to continue his work over a longer period of time to see if the impact of sulfate to sulfide conversion changes over several more years, well beyond the two years in the state study.