Concentrations of pesticides in silicone bands placed in National Wildlife Refuges of the Sacramento River Valley of California, 2023

To better understand pesticide exposure, silicone band samples were placed in five National Wildlife Refuges in the Sacramento Valley of Northern California. Silicone bands, used as aerial passive sampling collection devices, were flag-pinned half a meter off the ground and deployed for 28 days in the spring of 2023 (total of 176 bands). Upon retrieval, silicone bands were extracted via sonication with ethyl acetate and evaporated to 0.2 milliliters in acetonitrile. Samples were analyzed for 198 pesticides and degradates using both gas and liquid chromatography-tandem mass spectrometry. Overall, 36 pesticides and degradates were detected in the silicone bands.