Temporal and spatial dynamics and predictors of neonicotinoid contamination in groundwater fed streams in central Wisconsin

Neonicotinoid Pesticides have increased in usage over the last 20 years since the first neonicotinoid was registered in the late 1990s. Some research on non-target organisms is completed during pesticide registration, however it is not enough to fully understand the extent of neonicotinoid’s impact on aquatic invertebrate communities. In the Central Sands region of Wisconsin that is predominantly known for sandy soils and vegetable production, very little is understood about how neonicotinoid concentrations in stream water vary throughout the year and across the region. Our research is trying to identify the temporal and spatial dynamics of neonicotinoid contamination in the central sands region of Wisconsin to identify what landscape components might drive higher concentrations in stream water to aid regulatory and management decisions to protect native aquatic invertebrates. 82 stream sampling sites across the region have been identified and sampled bimonthly over the course of the past 2 years and the concentrations of 2 neonicotinoids, imidacloprid and thiamethoxam, were quantified using purchased ELISA serology kits. This work is still ongoing and future plans for this project include a landscape analysis of land usage in the areas of groundwater influence for each of the sites using a groundwater flow model developed by the USGS in order to determine a relationship with land use and neonicotinoid concentration. These results will hopefully serve as a guide for natural resource managers in our system and potentially other systems to more accurately predict risk to aquatic invertebrates and better protect sensitive taxa.