Concentrations of pesticides in silicone bands as passive samplers and sediment in Pinnacles National Park and Bureau of Land Management lands in San Benito County, California, 2019-2021

To better understand the potential pesticide exposure, samples were collected from locations along two creeks in Pinnacles National Park and four creeks in nearby Bureau of Land Management (BLM) lands. Silicone bands were used as passive sampling devices (PSD) staked in the creek and above in the air (above the water line). Sampling was conducted in the summer from 2019 to 2021. PSDs were deployed for 2 to 4 weeks and sediment was collected once in 2020. PSDs were extracted via sonication with an organic solvent and sediment was extracted via pressurized liquid extraction and solid phase extraction cleanup. Samples were analyzed for 168 pesticides and degradates using both gas and liquid chromatography-tandem mass spectrometry. Overall, 22 pesticides and degradates were detected in the PSDs and 8 pesticides and degradates were detected in the sediment. These results can help determine which pesticides are detected in sensitive habitats in Department of Interior lands in San Benito County.