This project investigated the eco-toxicological hazard of two different sized TiO2 nanomaterials and one non-nano sized TiO2 reference material to organisms (water flea, fish embryo, earthworm) inhabiting different environmental compartments. Different effect levels (respiration, mobility, mortality, reproduction, embryonic development) were considered under relevant exposure scenarios.
Conclusion: the tests revealed that especially solar radiation has a strong influence on the toxicity of nano as well as non-nano scale TiO2 materials.
‘SSR in the Daphnia sp. acute immobilization test (OECD 2004a) induced toxicity of the TiO2 material in the low mg/L range when based on nominal concentrations and in the μg/L range when based on analytically measured concentrations,’ the report says. ‘The solar radiation test further indicates that the SSR induced toxicity of the TiO2 materials was not a nano specific characteristic because SSR induced the toxicity of nano as well as non-nano scale TiO2 materials.’
‘The present study shows the necessity of considering the photo activity of nano and non-nano scale TiO2 materials in their environmental risk assessment, e.g., by conducting ecotoxicity tests with simultaneous irradiation by sunlight. Neglecting the influence of sunlight results in a clear underestimation of the environmental risk associated with TiO2 materials.’
• See report entitled Environmental hazard of selected TiO2 nanomaterials under consideration of relevant exposure scenarios, Umwelt bundesamt, October 2014.