Protecting wild rice waters

Status of MPCA proposed changes to sulfate water quality standard to protect wild rice

The MPCA withdrew its proposal to change the water quality standard designed to protect wild rice from adverse impacts due to sulfate pollution. The MPCA will continue to work with the public and state, local, federal, and tribal partners to investigate ways to protect this important Minnesota resource.

Stay up to date

Sign for emails that keep you up-to-date on Minnesota's sulfate standard.



Chief Administrative Law Judge’s Order

PDF icon Chief Administrative Law Judge’s Order on Review (April 12, 2018)

MPCA response to the ALJ report

PDF icon MPCA response to the ALJ report on wild rice (wq-rule4-15nn)

Report of the ALJ/Chief ALJ

PDF icon Administrative Law Judge Report/Report of the Chief ALJ (wq-rule4-15mm)

MPCA response to comments

Proposed Rules and Notice of Hearing documents

Supporting documents

Documents being incorporated by reference into the proposed rules

Exhibits to the Statement of Need and Reasonableness

Hearing records

Additional information

PDF icon Analyzing alternatives for sulfate treatment in municipal wastewater (wq-rule4-15pp)


Research papers

  • Modeling hydrologic controls on sulfur processes in sulfate-impacted wetland and stream sediments, Ng, G.- H.C., A.R Yourd, N.W. Johnson, and A.E. Myrbo. 2017, Journal of Geophysical Research-Biogeosciences, 122, doi:10.1002/2017JG003822. (E-mail to request a copy: MPCA Hearing Exhibit L.2
  • Myrbo, A., E.B. Swain, D.R. Engstrom, J. Coleman Wasik, J. Brenner, M. Dykhuizen Shore, E.B. Peters, and G. Blaha. 2017.  Sulfide generated by sulfate reduction is a primary controller of the occurrence of wild rice (Zizania palustris) in shallow aquatic ecosystems. Journal of Geophysical Research: Biogeosciences.
  • Pollman, C.D., E.B. Swain, D. Bael, A. Myrbo, P. Monson, and M. Dykhuizen Shore. 2017. The evolution of sulfide in shallow aquatic ecosystem sediments – an analysis of the roles of sulfate, organic carbon, iron, and feedback constraints using structural equation modeling. Journal of Geophysical Research: Biogeosciences. 122.
  • Myrbo, A., E. B. Swain, N. W. Johnson, D.R. Engstrom, J. Pastor, B. Dewey, P. Monson, J. Brenner, M. Dykhuizen Shore, and E.B. Peters. 2017. Increase in nutrients, mercury, and methylmercury as a consequence of elevated sulfate reduction to sulfide in experimental wetland mesocosms. Journal of Geophysical Research: Biogeosciences.
  • Pastor, J., B. Dewey, N. W. Johnson, E. B. Swain, P. Monson, E. B. Peters, and A. Myrbo. 2017. Effects of sulfate and sulfide on the life cycle of Zizania palustris in hydroponic and mesocosm experiments, Ecological Applications, 27, 321-336.

Comments received. The official record of comments is maintained by the Office of Administrative Hearings. Comments can be viewed online ( or by arrangement with the Office of Administrative Hearings. Contact: Katie Lin 651-361-7900 or fax 651-539-0310.

The 2011 wild rice sulfate standard legislation directed the MPCA to form an advisory committee “to provide input to the Commissioner on a protocol for scientific research to assess the impacts of sulfate and other substances on the growth of wild rice, review research results, and provide other advice on the development of future rule amendments to protect wild rice.”  

The Wild Rice Standards Study Advisory Committee began meeting in October 2011. Members include representatives of Tribes, municipal wastewater treatment facilities, industrial dischargers, wild rice harvesters, wild rice research experts, and citizen organizations.