BREAKING: Popular lake near the Boundary Waters recognized as impaired for sulfate by the Minnesota Pollution Control Agency

Nov 14, 2023
Libby London

For Immediate Release
November 14, 2023
Contact: Libby London (612) 227-8407

Popular lake near the Boundary Waters recognized as impaired for
sulfate by the Minnesota Pollution Control Agency

It has taken years of effort and tens of thousands of dollars in lab and equipment costs, but the Campaign to Save the Boundary Waters’ tireless water quality monitoring work sheds light on Birch Lake whose pollution has been ignored until now

Join us for a press conference TOMORROW, Wednesday, November 15, at 2:30 p.m. at the Minnesota Capitol in Press Conference Room B971

Ely, MN – Today, The Minnesota Pollution Control Agency (MPCA) released its biennial draft impaired waters list (the 303(d) list) for 2024. The list includes Birch Lake and a portion of the Dunka River, which exceeds Minnesota’s wild rice sulfate standard of 10 mg/L. Birch Lake is a popular recreational lake in the Superior National Forest in the watershed of the Boundary Waters Canoe Area Wilderness (the Rainy River Watershed) near Ely and Babbitt. Birch Lake is officially designated as a wild rice lake. 

For more than four years, Northeastern Minnesotans for Wilderness (NMW), founder and lead organization of the Campaign to Save the Boundary Waters, has intensively monitored the waters of Birch Lake for sulfate through its water quality monitoring program. This effort unequivocally found that the lake exceeds state standards for sulfate. NMW’s data was deemed the most high-quality sulfate data for Birch Lake in the State of Minnesota’s possession, and approximately 90% of the water quality data on Birch Lake in the MPCA’s database was collected by NMW. 

Thank you to the Minnesota Pollution Control Agency and Commissioner Kessler for following the scientific evidence and listing Birch Lake as an impaired waterbody, stated Ingrid Lyons, Executive Director of NMW and the Campaign to Save the Boundary Waters, “NMW is a small but mighty group conducting professional-level scientific research that shined a light on the ignored pollution of Birch Lake. Thanks to my science team's tireless water quality monitoring, we are one step closer to protecting the Boundary Waters once and for all.” 

NMW has built a rigorous monitoring program. It produces solid water quality data, which we share with the 1854 Treaty Authority, the EPA, and State. The data reveal the serious mining pollution flowing into Birch Lake every day, and made the MPCA’s listing of Birch Lake as a wild rice water impaired for sulfate the correct and unavoidable decision,” stated Matt Norton, Director of Science and Policy at NMW and Save the Boundary Waters

Minnesota develops a list of impaired waters every two years, as the federal Clean Water Act requires. The list sets pollution reduction goals (TMDL) to restore the water to an improved level. If Birch Lake is officially recognized as impaired by the Environmental Protection Agency in April, the Clean Water Act will be triggered, and clean-up and mitigation of the pollutant will be enforced. It will then become much more difficult for dangerous mining projects to be permitted. The impaired waters list will be available November 14 until January 12 for public comment.

It has long been known that there is sulfate pollution in Birch Lake, but so far effectively nothing has been done to address it. In 2021, we rapidly expanded our water quality testing program after discovering that the state had in its possession almost no data on sulfate concentrations in the west end of Birch Lake, where mining pollution is discharged. The listing of Birch Lake means that the machinery of the Clean Water Act will begin to turn, requiring - we hope - cleanup of the mining pollution still being dumped into the lake,” said Lisa Pugh, Water Quality Monitoring Program Manager at NMW and Save the Boundary Waters 

The MPCA’s 10 mg/L sulfate water quality standard is designed to protect a specific beneficial use — the use of the wild rice grain as a food source for humans and wildlife (Minn. R. 7050.0224) Sulfate pollution changes the ecology of lakes and streams and can be toxic to wild rice; this is why the state standard limits sulfate pollution to less than 10 mg/L in wild rice waters like Birch Lake. Wild rice grows naturally in Minnesota lakes and streams, making it a unique and valuable resource. Because it’s an important food source for humans and animals, which many depend on for survival, wild rice water bodies are protected by a Minnesota water quality standard. In 1973, Minnesota adopted a sulfate standard to protect wild rice based on studies showing that wild rice was found primarily in low-sulfate waters. 

About NMW’s monitoring program:

In 2020, the federal Environmental Protection Agency (EPA) listed 30 Minnesota wild rice waters as impaired for sulfate -- something that Minnesota’s state Pollution Control Agency (MPCA) had not done, despite data showing the impairments and the federal Clean Water Act’s requirement that all impaired waters be listed every two years. NMW’s staff discovered that the MPCA had almost no sulfate data from the southern and western half of Birch Lake. As a result, NMW developed a plan and assembled the equipment needed to begin a large water quality sampling operation in Birch Lake. Determined to do the job right and make the data count, NMW’s Lisa Pugh learned, followed, and began documenting compliance with EPA and MPCA quality-assurance and quality-control (QA/QC) methods. The results from NMW’s 2021 sampling were unequivocal: every sample in the western end of Birch Lake showed sulfate concentrations above the 10 mg/L sulfate standard. However, because the MPCA wanted to see additional years' worth of data, and Birch Lake was not listed in 2021 or in 2022. NMW continued with data collection. 

NMW’s data pinpoints the sources of that sulfate pollution - the sulfate is from the Dunka River and the stream called “Unnamed Creek.” The data pinpoints exactly where within those two tributaries’ sub-watersheds the pollution originates. Both tributaries have open-pit taconite mines in their sub-watersheds. Dunka River flows between an active taconite mine pit called the Peter Mitchell Pit, and a closed and flooded taconite pit called the Dunka Pit. Both mine pits discharge mine pit water into the Dunka River. Unnamed Creek receives acid mine drainage (AMD) with extremely high sulfate levels flowing from massive piles of weakly mineralized copper-nickel-sulfide waste rock. That waste rock once sat as overburden atop the taconite ore slated to be mined in the Dunka Pit and was removed and placed into massive piles. That sulfidic rock has been producing acid mine drainage (AMD) since the 1970s when the ore was dumped on the east side of the open pit. 

The Dunka River water has sulfate concentrations of 35 mg/L, which is 20 times higher than background levels. Unnamed Creek has sulfate concentrations of 326 mg/L, which is 180 times higher than background conditions in clean rivers where there is no mining pollution.  

The quality of NMW’s data has been vouched for by the MPCA and expert scientists. A robust collection of multi-year water quality data is critical to permanently protecting the Boundary Waters watershed from the threat of toxic hardrock mining pollution. 

"The most extensive and reliable sulfate concentration data available for Birch Lake were obtained by NMW’s monitoring program," said Dr. Patrick Brezonik, Ph.D., Professor Emeritus, University of Minnesota, "NMW has built a professional water monitoring program that has produced extensive water quality data on the Birch Lake area of the Boundary Waters watershed. Its trained monitoring staff followed appropriate sample collection methods, and a state-certified lab analyzed the water samples using accepted analytical methods. As a result, NMW has produced a large quantity of reliable water quality data in and around Birch Lake, which is essential to provide science-based answers to important water quality questions. Indeed, I am impressed with their operation.” 

Dr. Brezonik is an environmental chemist researching surface water quality, former Director of the University of Minnesota’s Water Resources Center, and Former chair of the MPCA’s scientific peer review panel on the wild rice sulfate standard. 

A 2017 report by the Minnesota Pollution Control Agency describes the waters within the Rainy River Watershed area (where the Boundary Waters is located) as “exceptionally clean” and “immaculate” and concludes that "the majority of the waterbodies within this watershed had exceptional biological, chemical, and physical characteristics that are worthy of additional protection." The Boundary Waters is the nation’s premier lakeland National Wilderness Area and the most visited of all such areas. A defining characteristic is water: 24% percent of the Boundary Waters is water, and along with the Superior National Forest, it contains 20% of all the freshwater in the entire National Forest System.


A vast collection of peer-reviewed science shows that if a Twin Metals mine was built along the rivers and streams flowing into the Wilderness, pollution and environmental degradation would be certain. A peer-reviewed independent study from Harvard University showed that protection of the Boundary Waters from the proposed sulfide-ore mine would result in dramatically more jobs and more income over a 20-year period. Nearly 70 percent of Minnesotans support permanent protection for this priceless Wilderness area.