Comparison of In Vitro to In Vivo Data Generated in Bioaccumulation Studies

SETAC North America 2022 -- Fish bioconcentration or biomagnification studies are carried out to determine whether substances have the potential to bioaccumulate and have potential to biomagnify throughout different trophic levels. The concentration of test material accumulated in the fish over time is compared to that in the surrounding media or the diet and the rate of uptake and depuration are calculated. There are increasing requirements to conduct these studies on a broad variety of industrial chemicals, pharmaceuticals and crop protection products across the globe, resulting in the use of significant numbers of fish. The preferred method of testing requires three doses of chemical (including a control) with up to 100 fish per dose. However, following the revision to the OECD Test Guideline (OECD 305: 2012), there is now the option to test on one concentration and the control only, providing there is scientific justification. This has the potential to decrease the numbers of fish used in these tests by one third (100 fish per study). The best way to reduce animal numbers further is to replace animals altogether with validated in vitro alternative studies such as the OECD 319 study (Determination of in vitro intrinsic clearance using cryopreserved rainbow trout hepatocytes or S9 fractions). Animal care and use is conducted in alignment with applicable animal welfare requirements.