Titanium Dioxide Nanoparticles May Be Environmentally Disruptive

According to a new Northeastern University study, titanium dioxide nanoparticles (nTiO₂) can disrupt photosynthetic organisms vital to aquatic ecosystems. Long used in paints, coatings, cement, and tile to create bright white coloring, titanium dioxide is now used in nanoparticle form in cosmetics, sunscreens, food coloring, and even building products, particularly white concrete products that are claimed to clean the air (see “Clean Concrete—and Air—with TX Active,”

EBN May 2007). April Gu, Carla Cherchi, and other environmental engineers studied how nTiO₂ affects one blue-green algae organism that contributes to aquatic nitrogen and carbon cycles. The researchers found that algae growth was reduced by 90% and nitrogen fixation activity was diminished when the organisms were exposed to nTiO₂ at levels similar to those found in wastewater. Effects increased with exposure time and nTiO₂ concentrations. The laboratory study did not evaluate the effect of titanium nanoparticles in the environment, or whether such particles are released from common products. For more information visit www1.coe.neu.edu.