ECETOC Florence workshop on risk assessment of endocrine substances, including the potency concept.

The European regulation on plant protection products (1107/2009) and the Biocidal Products Regulation (EC Regulation 528/2012) only support the marketing and use of chemicals if they do not cause endocrine disruption in humans or wildlife species. Also, substances with endocrine properties are subject to authorization under the European regulation on the registration, evaluation, authorization and restriction of chemicals (REACH; 1907/2006). Therefore, the regulatory consequences of identifying a substance as an endocrine disrupting chemical are severe. In contrast to that, basic scientific criteria, necessary to define endocrine disrupting properties, are not described in any of these legislative documents. Thus, the European Center for Ecotoxicology and Toxicology of Chemicals (ECETOC) established a task force to provide scientific criteria for the identification and assessment of chemicals with endocrine disrupting properties that may be used within the context of these three legislative texts (ECETOC, 2009a). In 2009, ECETOC introduced a scientific framework as a possible concept for identifying endocrine disrupting properties within a regulatory context (ECETOC, 2009b; Bars et al., 2011a,b). The proposed scientific criteria integrated, in a weight of evidence approach, information from regulatory (eco)toxicity studies and mechanistic/screening studies by combining evidence for adverse effects detected in apical whole-organism studies with an understanding of the mode of action (MoA) of endocrine toxicity. However, since not all chemicals with endocrine disrupting properties are of equal hazard, an adequate concept should also be able to differentiate between chemicals with endocrine properties of low concern from those of higher concern (for regulatory purposes). For this purpose, the task force refined this part of their concept. Following an investigation of the key factors at a second workshop of invited regulatory, academic and industry scientists, the guidance was advanced further. For human health assessments it is based on the relevance to humans of the endocrine mechanism of toxicity, the specificity of the endocrine effects with respect to other toxic effects, the potency of the chemical to induce endocrine toxicity and consideration of exposure levels.