Estimated risk profiles of titanium dioxide and carbon nanotubes engineered nanomaterials (enms) in the Gauteng province environment

Abstract

This paper presents findings on the quantification of potential risks posed by nTiO2 and CNTs to the aquatic and terrestrial ecosystems. The risk quotient (RQ) was calculated as a ratio of modelled predicted environmental concentrations (PEC) to the predicted no-effect concentrations (PNEC). To illustrate the functionality of the environmental risk profiling using modelling tools, the model was applied to the Gauteng Province. Due to large input data uncertainties, three scenarios (minimum, probable and maximum) were considered in our model. In the aquatic environment, the PEC values ranged from 0.036 µg/L to 0.301 µg/L for nTiO2; and 0.005 µg/L to 0.045 µg/L for CNTs under the realistic dilution factor (Dk = 1). On the other hand, the PEC values in terrestrial environment were; 0.457 µg/L to 3.349 µg/L and 0.068 µg/L to 0.499 µg/L, for nTiO2 and CNTs, respectively.