抄録
There are no clear regulations for safety assessment on nanomaterials, and systematic assessment methods are now examined in many countries. In Japan, it is examined how to handle nanomaterials under the Chemical Substance Control Law. NEDO project activities discussed extrapolation of 4-week inhalation into 13-week inhalation in rats given the results obtained by intratracheal administration on representative nanomaterials, and proposed determination of period-limited occupational exposure limit. In the EU, a recommendation on the definition of nanomaterials was adopted by the European Commission in October 2011 while the debate over relation to the revision of REACH scheduled for 2012 is ongoing. In the US, CNTs and fullerene are regarded as new chemical substances under TSCA Sec. 5, and those nanomaterials which are not listed in the TSCA inventory require submission of a premanufacture notification at least 90 days prior to manufacture or import. Thus, the trend to regulate nanomaterials is intensifying; however, the activities in each country are not harmonized. Given those gaps we examined utility of our newly developed multidimensional evaluation scheme for safety assessment on nanomaterials. This is a scheme for evaluating industrial materials in consideration of manufacturing processes and assessment of nanomaterials included in a finished product. Evaluations on CNTs, fullerene, titanium oxide, silver, and cerium oxide were simulated. The results showed that the scheme’s final stage could be reached in all cases; however, this scheme is conditional upon verification of intratracheal dosing, accumulation of inhalation background data, and development of environmental risk assessment. Therefore, it is considered that technology enhancement on those concerns will allow the scheme to evolve into a more sophisticated design.
