How error-prone bioaccumulation experiments affect the risk assessment of hydrophobic chemicals and what could be...

Bioaccumulation is one of the three criteria for the PBT assessment of chemicals, where P stands for persistence, B for bioaccumulation, and T for toxicity, which is a cornerstone for the "Registration, Evaluation, Authorization, and Restriction of Chemicals" (REACH) in the EU. Registrants are required by REACH to submit data on bioaccumulation if the chemical is manufactured in and/or imported to the European Economic Area at more than 100 t/year. Most of the experimental bioaccumulation studies submitted were on the bioconcentration factor (BCF) and were conducted prior to 2012, before the OECD Test Guideline 305 on Bioaccumulation in Fish was updated. An analysis of the submitted data revealed that many of the experimental data, but also the data from QSARs and other calculation methods, underestimate the actual bioaccumulation potential of hydrophobic substances considerably. One of the main reasons in the nonexperimental studies is that the BCF is related there to the total concentration of the chemical in water and not to the dissolved chemical concentration. There is therefore an urgent need to reassess the bioaccumulation potential of the hydrophobic substances registered under REACH. Based on the model calculations in the present study, between 332 and 584 substances that are registered under REACH are likely to bioaccumulate in the aquatic environment-many more than have so far been identified in the B assessment. Integr Environ Assess Manag 2023;19:792-803. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).