The Ministry of Health, Labor and Welfare has been developing the methodology of screening of tens of thousands of suspected endocrine disruptors for hormonal activities in order to establish a priority list for detailed hazard evaluation studies. It is also engaged in the methodology of the definitive studies in parallel (see the scheme).
A battery of in silico, in vitro and in vivo tests ((i), (ii) and (iii) in the scheme diagram) should permit successive examination of hormonal activities of so many substances.
The priority list may be improved progressively by re-sorting (e.g. in the order of decreasing hormonal activities) as new information or screening results are obtained. Additional prioritization criteria may be introduced, such as production information, for ordering in a more general viewpoint. The detailed tests (currently under development) will start from the top compound in the priority list. The resulting hazard evaluation, along with evaluation of actual exposure, will lead to a risk evaluation which will divide the reviewed substances into what needs risk management and what does not. Appropriate measures will be taken for the former, while the latter will be put on hold as long as new findings require reappraisal. Notwithstanding this principle, the evaluation of hazard, exposure and risk may be conducted immediately of substances for which large-scale tests have already made with results sufficient for the evaluation of hormonal activities, as is the case for pesticides for which multigeneration tests have been finished.