Pesticide Concentrations in American Bullfrog (Lithobates catesbeianus) Tadpoles Collected from Ponds and Reservoirs near Mead, Nebraska

To evaluate the potential uptake and accumulation of pesticides in amphibians, American bullfrog (Lithobates catesbeianus) tadpoles were collected from surface water sites (four ponds and one reservoir) in 2021 near Mead, Nebraska. Sites were located in the landscape surrounding the AltEn ethanol plant, a plant which had previously received pesticide treated (coated) seeds. Tadpoles were collected in November 2021, these tadpoles hatched in June 2021. The tadpole tissues were dried, homogenized, and then extracted using acetonitrile at 100 °C. Samples were analyzed for 166 pesticides and degradates using both gas and liquid chromatography-tandem mass spectrometry. Overall, 14 pesticides and degradates were detected in the tadpole tissue. Pesticides detected included neonicotinoid insecticides (clothianidin) and their degradates, other insecticides (bifenthrin), fungicides (fluoxastrobin, ipconazaole, metconazole, propiconazole, pyraclostrobin, tebuconazole) and degradates, and the historically used insecticide p,p’-DDT and its degradates (p,p’-DDE and p,p’-DDD). These results can help determine which pesticides may accumulate in amphibians.