Risk assessment of endocrine disruptors: Does unresolved uncertainties require extra precaution?

Minimising exposure to endocrine disruptors (EDs) is a priority within the European Union's political agenda. These chemical substances interfere with the endocrine system, leading to adverse effects on human health and the environment. Despite extensive research, significant uncertainties remain regarding safe levels of exposure to EDs. This paper highlights the need for cautious risk assessment due to substantial knowledge gaps, limitations in testing and unresolved questions about thresholds, non-monotonic dose-responses and low-dose effects. On this basis, we recommend a precautionary approach to risk assessment of EDs and in general support initiatives to reduce exposure by phasing out use and production. In cases where EDs are found in for instance food and drinking water, we propose the use of an additional uncertainty factor of 10 (as default) for the nature of ED effects to ensure more protective risk assessments. Our recommendations aim to contribute to the ongoing discussion on how to effectively manage the risks associated with endocrine disruptors. • There is a growing need for risk assessment of endocrine disruptors (EDs) • Significant uncertainties remain in deriving safe levels of exposure to EDs • Uncertainties include major knowledge gaps, testing limitations, questions around thresholds, and potential for non-monotonic and low-dose effects • Applying an additional uncertainty factor of 10 for ED effects is recommended as a pragmatic precautionary approach