The primary goal of the Minnesota Department of Agriculture's surface water monitoring is to provide detailed information on the occurrence and concentrations of pesticides in Minnesota's surface waters. Protection of Minnesota's citizens and water resources from agricultural chemicals is the fundamental purpose of this goal. The program focus is monitoring of streams and rivers in the agricultural and urban areas of the state.
In 1987, the Minnesota Legislature amended the Minnesota Pesticide Control Law (MN Statute 18B.04). It directed the Minnesota Department of Agriculture (MDA) to determine the impact of pesticides on the environment, including the impacts on surface water and groundwater.
In response to this charge, the MDA initiated a pesticide groundwater monitoring program in 1987. In 1991, surface water monitoring began. MDA also conducts edge-of-field water quality monitoring for nutrients and sediment. The MDA has one of the most comprehensive pesticide monitoring programs in the country.
In 2015, there were 82 sampling locations, 1,010 pesticide samples collected and over 52,000 individual analyses.
For additional information view the yearly monitoring reports and other resources.
Three pesticides have been designated as "surface water pesticides of concern" by the Commissioner of Agriculture. Acetochlor and atrazine (herbicides) were designated in 2012, and chlorpyrifos (insecticide) was designated in 2012. Designation as a "surface water pesticide of concern" initiates chemical specific best management practices (BMP's) and increased water quality analysis. The designation as a "surface water pesticide of concern" evaluates both detection of the pesticide in Minnesota surface waters and the concentration relative to water quality standards and/or reference values.
All data collected by the MDA are evaluated by the Minnesota Pollution Control Agency (MPCA) to determine if pesticide water quality impairments occurred. While MDA detects pesticides in surface water across the state, rarely do pesticide detections violate the water quality standards developed by the MPCA and or the United States Environmental Protection Agency to protect aquatic life.
There are currently 5 waterbodies in Minnesota proposed or designated as impaired on the USEPA 303(d) Impaired Waters List for currently registered pesticides as a result of MDA surface water pesticide monitoring:
The 2015 and 2016 MDA pesticide water quality data will be assessed as part of the 2018 USEPA 303(d) Impaired Waters List. The Le Sueur River and Beauford Ditch were designated as impaired for acetochlor on the 2008 USEPA 303(d) Impaired Waters List, and were removed on the 2014 USEPA 303(d) Impaired Waters list due to improved acetochlor water quality conditions over several years and outreach conducted by the MDA.
Visit the MPCA Minnesota Impaired Waters List for more information.
The MDA will continue to improve its program to expand monitoring to new locations and to include additional pesticide analytes, if resources are available. Finally, MDA is committed to maintaining its long-term data record to allow for continued trend analysis.