USGS Scientist to Discusses the Impacts of Agricultural Runoff in California’s Bay-Delta

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Research Chemist, Dr. Michelle Hladik, presented her research on current-use pesticides being introduced into certain areas of California’s Bay-Delta ecosystem. Dr. Hladik’s presentation took place at the Society of Environmental Toxicology and Chemistry (SETAC) Annual Meeting, Toronto, Canada during the first week of November.

Bay-Delta Location Map

Map showing location of California's San Francisco Bay-Delta​​​​​​​

The Cache Slough/Liberty Island complex and the Yolo Bypass are areas of critical habitat for several Bay-Delta fish species including the threatened Delta Smelt. In addition, recent research suggests that the Yolo Bypass can serve as an important source of phytoplankton and zooplankton, benefitting fish downstream. However, these areas are impacted by agricultural and urban runoff containing mixtures of current-use pesticides which may have direct, harmful effects on fish as well as on plankton production and quality. Dr. Hladik and her team collected samples from these areas. The samples were analyzed for over 150 current-use pesticides and pesticide degradates in water, suspended sediment, and zooplankton.

SETAC was formed in the late 1970s due to concerns that had developed in over the last few decades over the effects of increased pesticide use. SETAC came together in response to the need for a need for a multidisciplinary organization to address a widening array of issues. This year’s annual meeting Toronto will mark the 40th time the society formally began convening in 1979.