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Integration of Climate Change into the Multiple Stressor Risk Assessment for the Yakima River, Washington, USA
Citation:
Landis, W., John F. Carriger, J. Hader, C. Mitchell, R. Nathan, AND E. Sharpe. Integration of Climate Change into the Multiple Stressor Risk Assessment for the Yakima River, Washington, USA. Presented at SETAC North America 44th Annual Meeting, Louisville, KY, November 12 - 16, 2023.
Impact/Purpose:
To present the results of a collaborative effort for incorporating climate change adjustments into multiple stressor risk assessment from a case study involving the chinook salmon. This research is a product of the SETAC Pellston conference “Integrating Global Climate Change in Ecological Risk Assessment” held June 2022 at the Oscarborg Fortress Conference Center, Oslo, Norway.
Description:
A key question in understanding the implications of climate change is how to integrate ecological risk assessments that focus on contaminants with the environmental alterations from climate predictions. This report summarizes the results of integrating climate change with the use of agricultural pesticides in the Yakima River basin of Washington State. The original study (Mitchell et al. 2021) used the Bayesian network relative risk model to integrate risk. The Bayesian network incorporated an adverse outcome-based pathway to describe the effects of pesticide mixtures on fish survivorship and reproduction. Other pathways described the effects of water quality. The endpoint was no net loss to the Chinook population. Inputs to the model were all based on direct measurements from the site. In our study, a number of additional pathways were integrated to capture possible effects of a changing climate. Different levels of pesticide application were incorporated to capture different strategies to control pests in the future. Projected changes in water quality parameters were based on Ficklin et al. (2013), who used a suite of climate change models to generate probability distributions describing changes to conditions in the years 2050 and 2080. Our findings indicate that the largest driver of risk is the direct impacts climate change on temperature and dissolved oxygen content, rather than changes in pesticide exposures. The results suggest the Yakima metapopulation will not meet the goal of no net loss. It appears that climate change will have a major influence on the population dynamics and therefore risk to the Chinook population. If preservation of Chinook salmon is the goal, risk mitigation options should be planned and implemented by state, federal regulators and stakeholders in the near term. This research is a product of the SETAC Pellston conference “Integrating Global Climate Change in Ecological Risk Assessment” held June 2022 at the Oscarborg Fortress Conference Center, Oslo, Norway.