USDA Conservation Programs and Pesticides in Great Plains Depressional Wetlands—Texas to North Dakota

Pesticides were detected regularly, but not always, in wetlands from all land uses across the entire study area, although individual sites typically contained only one or two pesticides. Herbicides were the dominant pesticides detected, as would be expected given their widespread use for controlling weeds in cropland landscapes. Fungicides and insecticides were detected much less frequently, likely because they are used only as needed to manage regionand field-specific pest outbreaks. Though pesticides were found regularly in sediments of all land uses, the frequency of detection and concentration of the pesticide was affected by land use. For example, in the Southern WHP trifluralin detections in wetlands located in CRP were only a third of those in wetlands located in cropland. The same trends were observed for herbicide concentrations in the Southern and Northern WHP, where levels were significantly lower for wetlands located within CRP or native grassland than for wetlands located within cropland. Similar trends were observed for wetlands in the PPR.