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Extrapolating from laboratory-based aquatic toxicity tests to fish populations: Data from diazinon and carbaryl exposures
Citation:
Flynn, K., M. Etterson, N. Pollesch, S. Kadlec, AND F. Whiteman. Extrapolating from laboratory-based aquatic toxicity tests to fish populations: Data from diazinon and carbaryl exposures. SETAC North America, Sacramento, CA, November 04 - 08, 2018.
Impact/Purpose:
Under FIFRA, the USEPA conducts risk assessments for pesticide registration. While the need for population-level assessment has long been recognized, the data submitted often comes from standardized aquatic toxicity tests that do not include population-level endpoints. Therefore, the Fish Translator is being developed to link laboratory measured effects to population-level outcomes. As part of this effort, laboratory tests with model fish species (Japanese medaka or fathead minnow) have been conducted with the acetylcholinesterase inhibitors diazinon and carbaryl. The data produced is being integrated into the Fish Translator and adverse outcomes at the population-level modeled by the Fish Translator. When sufficiently developed, the Fish Translator can be a tool used by the USEPA to predict the risk of changes to population structures from pesticide exposure.
Description:
The United States Environmental Protection Agency (USEPA) assesses the risk of pesticides that are registered under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) to the environment and non-target wildlife and fish. A fundamental challenge in this process is the extrapolation from laboratory-based aquatic toxicity testing, which collects data on the individual fish, to population-level impacts. Currently, we are developing a structured population modeling (called the Fish Translator) that is intended to bridge the gap between effects observed in standardized aquatic toxicity tests often submitted during the FIFRA pesticide registration process, and potential outcomes of pesticide exposure to fish populations. As part of this research effort, laboratory tests on fish exposed to pesticides have been conducted to provide data on the relationship between growth and reproductive output (i.e. initiation of spawning, duration of spawning, and fecundity) to help parameterize the Fish Translator model. Specifically, Japanese medaka (Oryzias latipes) were exposed to either diazinon (an acetylcholinesterase inhibitor), reared at reduced food rations, or both to dis-entangled the reproductive and growth effects of a pesticide and the relationships between exposure, growth, and reproduction. Additionally, a standard Fish Early Life Stage Test (OCSPP 850.1400) with carbaryl (another acetylcholinesterase inhibitor) was conducted, exposing fathead minnows (Pimephales promelas) which were then reared without exposure to reproductive competence. The goal is to link adverse outcomes of an early life exposure (data often submitted under FIFRA) to adverse reproductive outcomes later in life that, in turn, are applicable to populations and population modeling. The effects observed in the laboratory of these two pesticides on the reproductive output of either Japanese medaka or fathead minnow were used in the Fish Translator to predictive population-level impacts on fish species with similar life history parameters.