Minnesota’s sulfate standard to protect wild rice

The MPCA's sulfate standard for wild rice has been a topic of much interest and activity in recent months. On this page, the MPCA will share information about ongoing studies, current and future rulemaking, and other MPCA news related to this standard.

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Background

Wild rice plants grow in lakes and slow-flowing streamsWild rice is an important component of aquatic communities in parts of Minnesota, particularly northern Minnesota. It provides food for waterfowl, and shelter for animals and fish. Wild rice is also a very important cultural resource to many Minnesotans, and is economically important to those who harvest and market wild rice.

Sulfate is a natural chemical commonly found in air, soil and water. It can be found at varying concentrations in discharges from permitted facilities such as mining operations, wastewater treatment plants and other industrial facilities. The primary factor in sulfate loading to surface water is the surface geology of Minnesota. For example, the glaciers left relatively high-sulfur soils across southwestern Minnesota, which contribute sulfate to lakes and streams.

Past studies have shown that elevated levels of sulfate were detrimental to the growth of wild rice so Minnesota adopted a standard in 1973 to protect this important resource. This 10 mg/liter sulfate standard, which is found in Minnesota Rules 7050.0224, subpart 2, protects “water used for production of wild rice during periods when the rice may be susceptible to damage by high sulfate levels.”

Concerns about the 10 mg/L sulfate standard

The MPCA is striving to clarify current and future implementation of this standard. States and authorized Tribes are required to review and amend their water quality standards every three years. As part of its 2012 Water Quality Standards Triennial Review, the MPCA intends to clarify the definition of “water used for production of wild rice.”

While revision of the 10 mg/L numeric sulfate standard continues to be evaluated, it is unlikely that sufficient data will be available to propose a revision to the numeric standard for the 2012 triennial review. Based on a review of available studies, MPCA believes that additional information is needed to further evaluate the wild rice sulfate standard.

Study protocol

To acquire the necessary information to further evaluate the wild rice sulfate standard, the MPCA first needs to establish a testing protocol for additional wild rice studies. To help inform the protocol development, the MPCA consulted with the U.S. Environmental Protection Agency (EPA) and Tribal representatives and met with interested/affected stakeholders such as the Chamber of Commerce and Minnesota Environmental Partnership. The purpose of these meetings was to:

1. get input on the protocol development process, including researchers/experts to connect with;
2. identify and discuss considerations for the protocol; and
3. learn how best to keep interested parties informed about progress.

The MPCA will also meet with technical experts to discuss the details of the protocol. The objectives for this meeting are:

1. Share understanding of what is known about the effects of sulfate and sulfide on wild rice.
2. Identify the most critical “unknowns” and associated hypotheses, needed to inform further evaluation and, if warranted, revision of the wild rice and sulfate standard.
3. Recommend study design(s) and methods to test the most critical hypotheses.

The following PDF files contain the agenda and technical discussion document for the May 9 meeting:

• Meeting agenda (wq-s6-40a)
• Discussion document (wq-s6-40b)

Presentations from the May 9 meeting and the straw proposal used in the afternoon breakout sessions.

• Standards overview (wq-s6-40c)
• Summary of feedback on hypotheses (wq-s6-40d)
• Straw proposal for breakout discussion (wq-s6-40e)

See below for meeting notes and feedback from the May 9 meeting. Comments from the morning discussion on hypotheses and afternoon breakout sessions are grouped by topic area.

• Meeting Notes and Feedback from May 9, 2011, Wild Rice and Sulfate Technical Meeting (wq-s6-40g)

See below for comments received on the draft protocol (general comments and comments by the Wild Rice Standards Study Advisory Committee) and a copy of the Final Protocol:

• Comments Received on Sulfate Standard to Protect Wild Rice Study Protocol (wq-s6-42c)
• Sulfate Standard to Protect Wild Rice: Final Protocol (wq-s6-42h)
• Wild Rice Standards Study Final Protocol (wq-s6-42b)

Wild rice standards study

Once the protocol is developed, funding will be needed to implement the studies. The studies would evaluate the toxicity of sulfate to wild rice across the full life cycle of the plant.

Based on protocol discussions to date, the MPCA believes that the Wild Rice Standards Study will be comprised of one or more studies that include a “field” investigation of the water quality and sediment chemistry associated with exiting natural wild rice stands, and an “experimental” study or studies that investigate the mechanisms by which elevated sulfate levels impact wild rice. This would include testing of a range of sulfate concentrations.

During the study, the MPCA would assemble and support a stakeholder group to ensure communication among interested parties is maintained, and would continue to consult with EPA and Tribal representatives. If the study is funded, the MPCA will work with affected parties to determine the composition of the stakeholder group.

A preliminary field survey of 50 sites was conducted in August and September of 2011 by the University of Minnesota. The purpose of the study was to characterize wild rice habitat. The data and information gained from this survey will be used to guide subsequent studies that will inform further evaluation of the Minnesota sulfate water quality standard for the protection of wild rice. Please see the following file for a description of the study methods and analyses.

• Wild Rice Sulfate 2011 Preliminary Field Survey (wq-s6-42g)

Upon completion of the study, the MPCA will undertake a rulemaking to adjust (as needed) the sulfate standard based on the results of the study. While the MPCA does not expect that every question regarding the effects of sulfate and other parameters on wild rice will be answered during a two-year study, we expect that sufficient additional information will be provided to allow for a further evaluation of the standard.

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Meetings

Tribal consultations and meetings

• March 12, 2012, Minnesota Pollution Control Agency Tribal Consultation on Water Used for Production of Wild Rice.  Discussion of the definition of "water used for production of wild rice."
• March 7, 2011, Minnesota  Pollution Control Agency Tribal Consultation on Sulfate and Wild Rice. Discussion of definition of “water used for production of wild rice” and wild rice and sulfate study protocol.

Stakeholder meetings

• March 10 and 30, 2011, Minnesota Pollution Control Agency meetings with Minnesota Chamber of Commerce. Discussion of wild rice and sulfate study protocol.
• March 17, 2011, Minnesota Pollution Control Agency meeting with Minnesota Environmental Partnership. Discussion of wild rice and sulfate study protocol; also some discussion of definition of “water used for production of wild rice.”
• April 7, 2011, Minnesota Pollution Control Agency meeting with  Minnesota Cultivated Wild Rice Council. Discussion of wild rice and sulfate study protocol .
  

Contact information

For information about the sulfate standard, contact Pat Engelking at pat.engelking@state.mn.us, 651-757-2340.