NANOTECHNOLOGY UPDATE: Nanoparticles seek and destroy groundwater toxins. “O’Carroll, who is visiting UNSW from the University of Western Ontario in Canada, has been trialling an innovative new groundwater clean-up technology using metal nanoparticles 500 to 5,000 times narrower than a human hair. The iron particles are injected directly into contaminated soil where they flow to the contaminants and initiate a redox reaction, whereby electrons are transferred between the particle and the pollutant. This reaction changes the oxidation state of the pollutant and diminishes its overall toxicity to safer levels, says O’Carroll.”