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Home > Protecting Our Lands & Waters > Clean Water Fund > Pesticide Monitoring

Pesticide Monitoring: Increased Capacity and Capability

The purpose of the Minnesota Department of Agriculture's pesticide monitoring program is to determine the presence and concentration of pesticides in Minnesota's groundwater and surface water. 

The MDA has been continuously monitoring the state's water resources for more than 30 years. With over three decades of monitoring data, the MDA operates one of the few programs with sufficient long term data to evaluate changes in water quality over time. Lab equipment for liquid chromatography with tandem mass spectrometry (LC-MS/MS) analytical methods

Clean Water funding has increased the capability and capacity of the pesticide monitoring program by purchasing a new analytical instrument in the MDA lab for a liquid chromatography with tandem mass spectrometry (LC/MS/MS) method. This state-of-the art equipment is capable of detecting a broader suite of chemicals at lower concentrations. 

Clean Water funding has allowed the MDA to increase the number of detectable pesticides, increase the sensitivity of detection of certain pesticides and increase the overall number of samples that can be analyzed on an annual basis.  As a result, Minnesota’s pesticide water monitoring program is one of the most comprehensive programs in the country and is regarded as a national leader. 

  • The MDA increased the number of detectable pesticides from 44 in 2009 to 138 in 2015.
  • Pesticides on the new method are now being quantified at a parts-per-trillion (ppt) level, which is a shift from the previous parts-per-billion (ppb) level.
  • Approximately 1600 pesticide samples were submitted for analysis during 2010, an increase of 600 samples compared to 2009. This increase of 600 samples should be maintained, but may be lower if dry weather conditions persist.

In general, the MDA looks for pesticides that are widely used and/or pose the greatest risk to groundwater or surface water. The MDA follows a pesticide selection process which prioritizes the specific compounds to be tested. Common compounds include pesticides applied in agricultural settings and those applied to lawns and gardens. The program is designed specifically to evaluate pesticides, however, analysis of nutrients and sediment is also conducted.

View MDA's 2015 Pesticide Monitoring Report (PDF: 16.15 MB / 248 pages) for details about water quality in the state of Minnesota. Monitoring reports from previous years are available on MDA's Monitoring and Assessment web page

General Information about MDA's Pesticide Monitoring Program

The MDA has established 10 Pesticide Monitoring Regions to provide a framework for conducting pesticide monitoring. Areas within a region contain similar land and water features and similar types of pesticide use practices. By dividing the state into regions, the MDA can provide information about the effects of pesticides in each unique area of the state.

Regions 4 and 9 are vulnerable to groundwater contamination and receive more intensive monitoring.

  • Region 4 is vulnerable because of widespread sandy soils
  • Region 9 is vulnerable because of shallow bedrock, sinkholes, and underground caves (referred to as karst geology)

In both of these areas, low levels of pesticides that are below health standards, are frequently detected in shallow groundwater. The frequency of detection for some chemicals is increasing as new equipment is able to detect some pesticides at much lower concentrations. 

Groundwater Monitoring

Minnesota Department of Agriculture staff collecting a groundwater sampleTo monitor in areas with shallow groundwater, specially designed wells are installed by the MDA in or near areas with row crop agriculture. Monitoring in these highly vulnerable areas ensures early detection if pesticides are present, and is considered a preventive and proactive approach to protecting Minnesota's waters.

The MDA monitors groundwater wells in eight of the ten Pesticide Monitoring Regions in the state. Pesticide Monitoring Regions 2 and 3 are not currently monitored for agricultural pesticides because of the low usage of these pesticides in the area. The MDA monitors groundwater in urban areas in cooperation with the Minnesota Pollution Control Agency (MPCA).

Surface Water Monitoring

The MDA monitors streams and rivers throughout the state. More frequent sampling occurs in areas that have historically exhibited higher concentrations of pesticides. Samples are generally collected during the late spring and early summer when the potential for pesticide movement is the greatest.


Monitoring efforts are coordinated with other state agencies and local units of government. The MDA also participates with a variety of statewide monitoring surveys in cooperation with other state agencies. These partnerships are essential and make it possible to collect consistent and reliable information.

 Related webpages:

Looking for additional water data and information? Check out the Key Water Information Catalogue

 MDA Contacts

Bill VanRyswyk
Bill.Vanryswyk@state.mn.us ~ 507-344-5260

Dan Stoddard
Assistant Division Director
Dan.Stoddard@state.mn.us ~ 651-201-6291