Exposure scenarios for nanomaterials under REACH
Stefano CASTELLI (ENEA)
The Exposure Scenario (SE), as defined under REACH, is a set of parameters that describe the way a substance is manufactured or used and the measures applied to control human exposure and releases to the environment. It includes operational conditions (duration and frequency of use of a substance, amount used, process temperature or pH) and applied risk management measures. The ES is fundamental in the quantitative exposure estimation for risk assessment and is a communication tool in the supply chain. The main quantitative value reported in a SE is the Risk Characterization Ratio (RCR). In order to determine this value, two fundamental values have to be established: exposure and toxicological limits. As properties of substances in nanoform are not fully understood yet, this task is very difficult and the development of exposure scenarios for nanomaterials is a challenge that the scientific community is facing, with different approaches.
The simplest way for exposure is an experimental measure. Anyway REACH reckons on the use of models that allow the possibility of extrapolation in different situations.
Till now only qualitative models applicable to engineered nanomaterials have been developed for exposure scenarios: in this work is described the model Stoffenmanager Nano 1.0.
As concern toxicological limits, waiting for the determination of official DNELs, Nano Reference Values (NRV) have been proposed.
