Pesticide Concentrations in Tadpoles Collected from Ponds and Reservoirs near Mead, Nebraska 2022-2024

The AltEn bioenergy plant (Mead, Nebraska, USA) previously (2015 to 2021) generated ethanol from almost 100% unused/expired treated corn seeds. This use of treated corn seeds as a feedstock for ethanol production resulted in accumulation of large amounts of contaminated wastewater and solid residue at the plant, a portion of which was applied to surrounding farmland. To evaluate the potential uptake and accumulation of pesticides in amphibians, American bullfrog (Aquarana catesbeiana (Shaw, 1802) [formerly Lithobates catesbeianus (Shaw, 1802)]) and native tadpoles were collected from surface water sites (four ponds and one reservoir) from June 2022 through June 2024 near Mead, Nebraska. Sites were located in the landscape surrounding the AltEn ethanol plant, a plant which had previously received pesticide treated (coated) seeds. The tadpole tissues were dried, homogenized, and then extracted using acetonitrile at 100 degrees Celsius. Samples were analyzed for 165 pesticides and degradates using both gas and liquid chromatography-tandem mass spectrometry. Overall, 22 pesticides and degradates were detected in the tadpole tissue. The highest concentrations detected include acetochlor (29.1 nanogram per gram wet weight [ng/g w.w.], herbicide), ipconazole (23.1 ng/g w.w., fungicide), and cyfluthrin (21.9 ng/g w.w., insecticide). These results can help determine which pesticides may accumulate in amphibians.