Since CeO2-nanoparticles induces specific toxicological effects, they do not belong to the group of so-called granular bio-persistent dusts (GBS). Inhalation exposure to CeO2 elicits inflammatory and fibrotic effects in the lungs of humans and rats. Data in humans as well as in animals indicate individually varying health effects due to inhalation of CeO2. In a long-term inhalation study with nanoscale CeO2-particles, cerium phosphate was clearly detected in rat bone tissue.
In an extensive 2-year-inhalationstudy using nanoscale CeO2-particles in rats, exposure concentrations as low as 0.1 mg/m3 elicited statistically significant granulomatous inflammation and interstitial fibrosis of the lung. With decreasing particle size, the proportion of the two stable cerium valence states increases in favor of the Ce3+ proportion. This leads to altered chemical-physical properties, including an increased redox potential (Ce3+/Ce4+) and higher solubility. In the biological system, the toxicity of CeO2-particles is primarily due to their redox potential at the particle surface. However, a toxic effect due to soluble parts of the CeO2 cannot be excluded.
About Dirk Walter
Dirk Walter holds a PhD in chemistry and in human biology and is an associate Professor for Chemistry at the Justus-Liebig-Universität in Gießen, Germany.He is the head of Chemistry and Physics Laboratories at the Institute for Occupation and Social Medicine (Gießen). In addition, he leads an interdisciplinary research team at the Institute for Inorganic and Analytical Chemistry. His research focus is on the Occupational toxicology on nanoparticles and dusts. Mechanism of reactions of oxidic inorganic solids represents a further focus of research.
Dirk Walter is a member of the Permanente DFG-Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area. Furthermore, he is a member of the Board of the German Society for Occupational, Social and Environment Medicine (DGAUM). Moreover, he is the chairman of the Board of the German Society for Thermal Analysis (GEFTA), Germany.