Exposure modeling of engineered nanoparticle
C. Som, N.C. Mueller, T. Sonderer, F. Gottschalk, R. Scholz, B. Nowack
Empa Materials Science and Technology, CH
Keywords: exposure, release, modeling, engineered nanoparticles, environment
Abstract:An elementary step towards a quantitative assessment of the risks of new compounds to the environment is to calculate their predicted environmental concentrations (PEC). The aim of this study was to use a life-cycle perspective to model the quantities of engineered nanoparticles released into the environment. The quantification was based on a substance flow analysis from products to air, soil and water. The following parameters were used as model inputs: estimated worldwide production volume, allocation of the production volume to product categories, particle release from products and flow coefficients within the environmental compartments. To cope with uncertainties concerning the estimation of the model parameters (e.g. transfer and partitioning coefficients, emission factors) as well as uncertainties about the exposure causal mechanisms (e.g. level of compound production and application), we utilized and combined probabilistic methods, sensitivity and uncertainty analysis. The method was applied to the engineered nanoparticles titanium dioxide, silver, carbon nanotubes, fullerenes, ZnO and carbon black. The PEC-values were then compared to the predicted no effect concentrations (PNEC) derived from the literature to estimate a possible risk. The results of this study make it possible for the first time to carry out a quantitative risk assessment of nanoparticles in the environment and suggest further detailed studies of nano-titanium dioxide.