The U.S. Environmental Protection Agency (EPA) published a draft deliberative entitled “State of the Science Evaluation: Nonmonotonic Dose Responses as They Apply to Estrogen, Androgen, and Thyroid Pathways and EPA Testing and Assessment Procedures”. In the document the U.S. EPA argues that while non-monotonic dose-response (NMDR) relationships exist, they are not common. The report further states that low dose effects do exist, but they are mostly relevant for molecular initiating events. Rather than identifying all effects for all endpoints, toxicological testing has the goal of identifying the potential for hazards after exposure. According to the EPA, it is therefore not necessary for toxicological tests to be modified in order to reflect upon these low dose effects. The report concludes that current testing strategies are unlikely to mischaracterize a chemical as a consequence of NMDR.
The draft report will undergo peer-review by the U.S. National Academy of Sciences