PMPC Meeting Agenda and Notes

Dan Stoddard, MDA, welcomed participants to the meeting, explained the purpose of the PMPC, and emphasized the importance of discussion and member feedback. PMCA Members and MDA leadership introduced themselves.

Kate Hall (meeting facilitator), MDA, went through housekeeping items and presented background slides on PMPC. The presentation provided an overview of the MDA’s Pesticide Management Plan, “common detection” and “surface water pesticide of concern” designations, and select comments received from members the previous year. The MDA’s Indigenous Land Acknowledgement statement was read.

MDA Presenter: Bill VanRyswyk

The presentation provided an overview of the MDA’s monitoring program and introduced the main sections of the 2022 report. Changes to the 2022 analyte list were highlighted along with groundwater and surface water program design elements.

Minnesota Department of Health Presenter: Kris Klos

The presentation described the different groups at the MN Dept. of Health (MDH) responsible for developing human health-based guidance values and the processes and data involved. Guidance including Health Risk Limits (HRLs), Health Based Values (HBVs), Risk Assessment Advice (RAA), and pesticide Rapid Assessments (RAs) were reviewed. Additional details were provided regarding the recent development of HBV and RAA values for the fungicide chlorothalonil and its degradate, respectively.

MDA Presenter: Kim Kaiser

The presentation focused on the groundwater results from the 2022 monitoring season. Current common detection pesticides were reviewed, and trend maps were presented showing changes in detection frequency and concentration for individual pesticide monitoring regions (PMRs). Pesticides detected in PMR 4 were highlighted along with neonicotinoid detections, detections of cyanazine degradates in private wells, and urban groundwater results.

Discussion focused on:

• The importance of clearly presenting trend data and the need to consider the time series graphs for detection frequency and concentration alongside color-coded trend maps.
   
• Health Risk Limits (HRLs) for cyanazine degradates
  • A member explained that previously there were not enough animal studies to develop HRLs for cyanazine degradates and asked if MDH had any updates.
  • There were no substantial updates on the topic, and it was noted that once a chemical is cancelled (as is the case with cyanazine), there typically is not a lot of new research being conducted on the chemical.

• Chlorothalonil and its degradate, 4-hydroxychlorothalonil
  • 4-hydroxychlorothalonil is classified as a “marginally performing analyte” due to analytical challenges related to recovery. This means that the concentration values reported for 4-hydroxychlorothalonil may under-represent environmental conditions.
  • MDH was unable to develop a HRL for 4-hydroxychlorothalonil due to data limitations. Instead, Risk Assessment Advice (RAA) was developed and is being used to evaluate concentration data in groundwater.
  • The potential to create best management practices (BMPs) for chlorothalonil was discussed. The MDA currently has BMPs for potato fungicides that can be promoted and additional BMPs may be considered.
     
• The MDA’s authority to regulate treated seed
  • The omnibus environment and natural resources bill (HF 2310) passed during the 2023 legislative session states that a person may not use, store, handle, distribute, or dispose of seed treated with pesticide in a manner that: (1) endangers humans, food, livestock, fish, or wildlife; or (2) will cause unreasonable adverse effects on the environment.
     
• Additivity of parent and degradate chemicals in evaluating concentration data
  • It was asked whether the detected concentrations of bentazon and its AIBA degradate should be combined.
  • The MDA defers to MDH for human health-based guidance and appropriately accounting for additivity.

MDA Presenter: Dave Tollefson

The presentation focused on the surface water results from the 2022 monitoring season. Current surface water pesticides of concern were reviewed, and trend maps were presented showing changes in detection frequency and concentration for individual pesticide monitoring regions (PMRs). Comparisons of detected concentrations to relevant standards or guidance values (i.e., reference values) were also presented, focusing on pesticide detected at concentrations >10% and >50% of relevant reference values. Additionally, the presentation focused on neonicotinoid detections and reviewed findings from the 2022 Polar Organic Chemical Integrated Sampler (POCIS) pilot study.

Discussion focused on:

• Whether there will be more sampling earlier or later in the year to better capture neonicotinoid detections
  • The MDA has expanded the sampling window at some sites to gain further insight on detection patterns (added April and September monitoring).
• Why the number of clothianidin 21-day average concentrations above the aquatic life benchmark increased in 2022
  • It was suggested that there may have been some carryover from the drought in 2021 when detections were suppressed.
• If there has been an increase in azoxystrobin sales
  • There has been a steady increase in sales in recent years. The increase may be in part related to new products for use in corn.
• Why acetochlor detections have been increasing over time
  • It was suggested that the increase may be related to increasing issues with weed control in soybean, though application rates have not increased.
  • Metolachlor is an alternative herbicide, but it was stated that is not as safe as acetochlor for some crops and doesn’t provide as much residual control.
• MDA’s acetochlor outreach
  • A member asked whether the MDA plans to change the current approach to acetochlor outreach and when actions move beyond best management practices (BMPs). 
  • Currently, a change in the approach is not anticipated. The MDA recently updated their acetochlor water quality BMPs and continues to promote these. The MDA’s actions are guided by the Minnesota Pesticide Management Plan; however, there is no set rule for when actions move beyond BMPs.
  • The MDA will continue to monitor acetochlor and evaluate the BMPs to determine if any additional actions are needed.
• Why there is only one acetochlor impairment despite many detections
  • It was explained that many of the acetochlor detections at concentrations at or above the numeric reference value do not meet the duration requirement (4-day) of the chronic standard. Typically, elevated acetochlor concentrations rapidly decrease.

Raj provided an update on treated seeds and MDA’s authority to take action to prevent unreasonable adverse effects. He explained that while MDA now has this authority, treated seeds will not be handled the same as pesticides. The MDA also received money for pollinator research which may be used to study pesticide treated seed.

Discussion focused on:

• Pesticides in precipitation
  • A member expressed concerns over the presence of pesticides in rain and requested the report focus more on these results.
• Aquatic life benchmarks and water quality standards for neonicotinoids
  • It was explained that MDA does not develop reference values and uses guidance from the MN Pollution Control Agency.
  • Currently, there are no promulgated standards for neonics in surface water. The neonics are on the MPCA’s list of standards to develop; however, they have not been prioritized.