Jemec A, Drobne D, Remškar M, Sepčić K, Tišler T
[ pdf ] [ site ] Environmental Toxicology and Chemistry, 2008

The effects of ingested nano-sized titanium dioxide (TiO₂; anatase, 15 nm) on the terrestrial isopod Porcellio scaber (Isopoda, Crustacea) after short-term (3-d) dietary exposure were studied. Activities of antioxidant enzymes, such as catalase (CAT) and glutathione-S-transferase (GST), in digestive glands were affected in a dose-independent manner, but higher-level isopod endpoints, including weight change, feeding rate, food assimilation efficiency, and survival, were not affected up to the highest tested concentration of TiO₂ in food (3,000 μg/g). Exposure concentrations of 0.5, 2,000, and 3,000 μg nonsonicated TiO₂/g food decreased CAT and GST activities, but intermediate concentrations (1, 10, 100, and 1,000 μg/g food) did not result in significant changes of enzyme activities. When the dispersion of TiO₂ was sonicated, no effects on enzyme activities or higher-level biomarkers were observed. The experimental setup with terrestrial isopods designed for dissolved chemicals also is suitable for testing the effects of ingested nanoparticles, but the presentation of toxicity data needs to be adapted according to the mode of action of the nanoparticles and their specific characteristics.