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A sensitivity analysis of pesticide concentrations in California Central Valley vernal pools
Citation:
Sinnathamby, S., J. Minucci, D. Denton, Sandy Raimondo, L. Oliver, Y. Yuan, D. Young, A. Pitchford, E. Waits, AND Tom Purucker. A sensitivity analysis of pesticide concentrations in California Central Valley vernal pools. ENVIRONMENTAL POLLUTION. Elsevier Science Ltd, New York, NY, 257:113486, (2019). https://doi.org/10.1016/j.envpol.2019.113486
Impact/Purpose:
This work was conducted to integrate exposure, effects, and chemical/species co-occurrence model output in the California Endangered Species Case Study task within the Ecological Modeling project of the Chemical Safety for Sustainability (CSS) Strategic Research Action Plans (CSS 18.04.06).
Description:
Vernal pools are ephemeral wetlands that provide critical habitat to many listed species. Pesticide fate in vernal pools is poorly understood because of uncertainties in the amount of pesticide entering these ecosystems and their bioavailability throughout cycles of wet and dry periods. The Pesticide Water Calculator (PWC), a model used for the regulation of pesticides in the US, was used to predict surface water and sediment pore water pesticide concentrations in vernal pool habitats. The PWC model (version 1.59) was implemented with deterministic and probabilistic approaches and parameterized for three agricultural vernal pool watersheds located in the San Joaquin River basin in the Central Valley of California. Exposure concentrations for chlorpyrifos, diazinon and malathion were simulated. The deterministic approach used default values and professional judgment to calculate point values of estimated concentrations. In the probabilistic approach, Monte Carlo (MC) simulations were conducted across the full input parameter space with a sensitivity analysis that quantified the parameter contribution to model prediction uncertainty. Partial correlation coefficients were used as the primary sensitivity metric for analyzing model outputs. Conditioned daily sensitivity analysis indicates curve number (CN) and the universal soil loss equation (USLE) parameters as the most important environmental parameters. Therefore, exposure estimation can be improved efficiently by focusing parameterization efforts on these driving processes, and agricultural pesticide inputs in these critical habitats can be reduced by best management practices focused on runoff and sediment reductions.
URLs/Downloads:
DOI: A sensitivity analysis of pesticide concentrations in California Central Valley vernal pools