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ICCVAM Biennial Report 2018-2019

Biennial Progress Report 2018-2019 Interagency Coordinating Committee on the Validation of Alternative Methods

Use of a Fish Embryo Toxicity Test for Prioritizing Testing of Environmental Contaminants

As part of ongoing assessments of wildlife health, DOI is investigating potential cardiovascular effects on fish from pesticides and pharmaceuticals frequently detected in surface waters and fish tissues. The U.S. Geological Survey's Columbia Environmental Research Center conducts high-content screening of compounds to formulate hypotheses and prioritize compounds for further toxicity testing. This approach reduces animal use, test compound needed, and waste by utilizing pre-feeding fish embryos in a microtiter plate format. This approach is also being used to better characterize toxicity of PAHs and oxygenated PAHs in groundwater samples over different trophic levels of a subsurface oil spill. These assays can provide evidence to justify larger-scale studies to determine actual risk versus perceived risk of contaminants.

The Center’s current high-content screening assay is a developmental cardiotoxicity assay that assesses total body length, pericardial area, intersegmental vessel area, circulation, and heart rate after a 72-hour exposure. This array of endpoints allows for a targeted assessment of toxicity. In addition to an LC50 estimate, the assay rapidly provides mode-of-action information, allowing formation of hypotheses on sublethal impacts of contaminants. Data derived from these studies on acute toxicity and mode of action for pesticides, pharmaceuticals, and PAHs/oxygenated PAHs will support a better understanding of potential effects on wildlife species.