In addition to toxicity, the potential of test chemicals to bioaccumulate is often assessed using fish. However, there are opportunities to reduce and replace the use of fish while advancing the goal of environmental protection.

In Vitro Methods to Predict Hepatic Clearance and Bioconcentration Factors

In 2018, two Organisation for Economic Co-operation and Development (OECD) Test Guidelines (TG) to determine in vitro hepatic clearance using rainbow trout hepatocytes and S9, and an associated guidance document (GD) were adopted by the OECD (OECD TGs 319A and 319B, OECD GD 280). In combination with in silico models, hepatic clearance can be used to predict bioconcentration factors for bioaccumulation assessment.

Reducing the Number of Fish Used in Bioaccumulation Testing

In July 2020, the US Environmental Protection Agency (EPA) released new guidance clarifying the number of treatment concentrations required for fish bioconcentration factor (BCF) studies for pesticide registration. The policy change brings the EPA into alignment with international regulations and will prevent as many as 240 fish from being used in BCF studies each year while safeguarding human health and the environment.

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