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MDA Presenter: Raj Mann and Dan Stoddard

The following updates from the MDA were provided:

1. Pesticide Management Plan (PMP) Revisions - The MDA is in the process of revising the PMP. Significant revisions include developing a process for removal of pesticides from list of "common detection" or "surface water pesticide of concern" status, updating the statutory language referenced, and various other technical changes related to pesticides and agricultural technology. A draft of the revised PMP will be published in the state register for public comment along with a summary of changes (anticipated in late 2021).
    
2. Chlorpyrifos Update - Several lawsuits have been filed for chlorpyrifos’s potential adverse effects on human health. Of particular interest is lawsuit filed in 2007 to revoke all chlorpyrifos tolerances and cancel all registrations based on adverse human health effects. The EPA denied this petition in 2019; however, in a ruling issued on April 29, 2021, the Ninth Circuit Court of Appeals vacated the 2019 denial of the petition and instructed the EPA to either modify chlorpyrifos’s tolerances and publish findings to show they are safe or to revoke all chlorpyrifos tolerances within 60 days. The decision on this from the EPA or 9th circuit court is awaited.
   
   The MDA has an ongoing special registration review focused on chlorpyrifos in Minnesota (scoping document is available on the Pesticide Special Registration Reviews page.
    
3. Legislative Report Recommendations - In 2020, there was an audit of the MDA’s pesticide programs. The audit report supported the continued monitoring of pesticides in water and recommended three additional analytes be added to the program (triphenyltin hydroxide, glufosinate-ammonium and ethylenethiourea [ETU]). Unfortunately, analysis of these chemicals by the MDA Lab is not feasible at this time based on available instrumentation and methodology. The MDA will continue to seek funding for lab equipment and explore analytical options.
    
4. MDA Laboratory Funding - The MDA had a legislative proposal to increase pesticide registration fees that would generate approx. $2,251,000 per year from pesticide gross sales. These funds would have been used to (1) replace analytical equipment required to maintain critical laboratory services, (2) replace Clean Water funding, (3) create two new urban pesticide positions, and (4) provide the necessary resources for the MDA Lab to expand pesticide monitoring and include specific analytes recommended by the audit. Ultimately, the Lab received $600,000 in general funds through the agricultural budget bill in 2021. These funds will be used to update/replace existing equipment, but they are not sufficient to purchase additional new equipment.

Discussion topics included:

• The MDA’s investigation into potential propazine sources.
  • Detections in surface water are likely the result of impurities in atrazine products. Propazine has not been sold in MN in over 30 years and detections correlated well with atrazine detections.
  • This relationship between atrazine and propazine is unique and similar trends with other chemicals (particularly triazines) have not been observed.
• Sources of metribuzin detections outside of PMR 4 and method reporting limits (MRLs) for its main degradates.
  • Detections have been limited and occur in different areas throughout the state. Because detections are erratic, the source has not been fully investigated by the MDA.
  • Metribuzin has been making a reappearance as part of pre-emergence tank mixes to address resistant weeds in soybean.
  • The MDA is not able to lower the MRLs for metribuzin and its degradates at this time.

• Availability of raw data for 4-hydroxychlorothalonil (report table only shows a single maximum concentration).
  • Requested data was sent after the meeting. Raw data is also available through the Water Quality Portal.
• The MDA’s actions regarding increasing metolachlor trends in groundwater.
  • The MDA is continuing to promote Water Quality Best Management Practices for Metolachlor (PDF).
  • While some PMRs do show increasing trends, concentrations remain well below human health reference values in groundwater. The MDA will continue to carefully monitor metolachlor and its degradates.
  • Increased metolachlor use is anticipated due to resistance issues with glyphosate and other herbicides.
• The continued use of Roundup-Ready crops despite the development of glyphosate-resistance.
  • Growers are continuing to use Roundup-Ready crops and glyphosate is still an important part of weed management programs from corn and soybean.
• The new addition of piperonyl butoxide to the monitoring list and the lack of detections.
  • Piperonyl butoxide is a synergist often used with pyrethroid insecticides. It has been detected by other monitoring programs, but it was not detected in 2020 by the MDA.