The German Umweltbundesamt (UBA) has published a study stating that ‘realistic exposure scenarios are necessary to properly assess the potential environmental risk of TiO2 materials’. The researchers also found that the toxicity of the titanium dioxide materials was not necessarily a nano-specific characteristic.
It was found that, after analysing various exposure scenarios, ‘ our tests revealed that especially solar radiation has a strong influence on the toxicity of nano as well as non-nano scale TiO2 materials’ – they postulate that ‘phototoxicity was driven by a combination of [other] factors’, since it is not ‘a nano-specific characteristic’. Mixture experiments showed that ‘the toxicity of the organic compound was not enhanced in the presence of the different-sized TiO2 materials’, and ‘OECD tests under laboratory light or darkness…observed no toxic effects to the test organisms’. The findings the team made act as the basis for their call for ‘the necessity of considering the photo activity of nano and non-nano scale TiO2 materials in their environmental risk assessment’.
This work was undertaken because UBA felt that, ‘despite the high scope of nanomaterial production and subsequent release into the environment, the special characteristics of nanomaterials are often not, or not sufficiently, considered in environmental risk assessment’. Considering OECD test guidelines, UBA looked to observe ‘more relevant exposure scenarios which are not covered by them’ – these included solar radiation, mixture experiments, and testing of embryonic development stages’.
Follow this link to read the full study.