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Evaluation of Time- and Concentration-dependent Toxic Effect Models for use in Aquatic Risk Assessments, Oral Presentation
Citation:
ERICKSON, R. J. Evaluation of Time- and Concentration-dependent Toxic Effect Models for use in Aquatic Risk Assessments, Oral Presentation. Presented at SETAC Annual Meeting, Tampa, FL, November 16 - 20, 2008.
Impact/Purpose:
Various models have been proposed for describing the time- and concentration-dependence of toxic effects to aquatic organisms, which would improve characterization of risks in natural systems.
Description:
Various models have been proposed for describing the time- and concentration-dependence of toxic effects to aquatic organisms, which would improve characterization of risks in natural systems. Selected models were evaluated using results from a study on the lethality of copper to juvenile fathead minnows that examined effects under continuous exposures of various durations and under pulsed exposures. Models were parameterized based on continuous exposure tests, and model assumptions were evaluated based on their goodness-of-fit to these tests. Predictions for pulsed exposure tests were made, and used to further evaluate model assumptions and compare model performance. These evaluations demonstrated good utility of these models, and showed better performance using models with multiple toxicity processes and with a deterministic, rather than a stochastic, approach for differences among individual organisms. For the types of exposures of interest in typical aquatic risk assessments, risk prediction differences among models were small, so that complex models might not be needed.