Distribution and Concentration of Neonicotinoid Insecticides on Waterfowl Production Areas in West Central Minnesota

Neonicotinoid insecticides have been reported to occur widely in surface waters, including those of wetlands within the Prairie Pothole Region (PPR). In the US portion of the PPR, the US Fish and Wildlife Service has established Waterfowl Production Areas (WPAs) in an effort to enhance waterfowl production. Most WPAs have an area of protected upland surrounding wetlands that can act as a buffer to reduce the transport of contaminants, including pesticides. We assessed the extent that neonicotinoid insecticides occurred in the ponded water of wetlands within WPAs located along a gradient of agricultural influence throughout west-central Minnesota. Of the five neonicotinoids we tested for, two were not detected. However, at least one of the other three, imidacloprid, clothianidin and thiamethoxam, were detected in 29% of our wetland water samples. Additionally, both the occurrence and total concentrations of neonicotinoids were higher in sites with higher surrounding crop use. Neonicotinoid insecticides, if persistent for long periods of time, have the potential to affect aquatic-invertebrate communities within PPR wetlands. Our research indicates that areas often perceived as protected may still be at risk to neonicotinoid contamination, emphasizing the importance of maintaining effective grassland buffers around wetlands.