Int. J. Environ. Res. Public Health 2015, 12, 1253-1278; doi:10.3390/ijerph120201253 OPEN ACCESS International Journal of Environmental Research and Public Health ISSN 1660-4601 www.mdpi.com/journal/ijerph Review Environmental Geochemistry of Cerium: Applications and Toxicology of Cerium Oxide Nanoparticles Jessica T. Dahle 1 and Yuji Arai 2,* 1 School of Agricultural, Forest and Environmental Science, Clemson University, Clemson, SC 29634, USA; E-Mail:
[email protected] 2 Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign Urbana, IL 61801, USA * Author to whom correspondence should be addressed; E-Mail:
[email protected]; Tel.: +(217)-244-3602. Academic Editor: Mónica Amorim Received: 22 September 2014 / Accepted: 15 January 2015 / Published: 23 January 2015 Abstract: Cerium is the most abundant of rare-earth metals found in the Earth’s crust. Several Ce-carbonate, -phosphate, -silicate, and -(hydr)oxide minerals have been historically mined and processed for pharmaceutical uses and industrial applications. Of all Ce minerals, cerium dioxide has received much attention in the global nanotechnology market due to their useful applications for catalysts, fuel cells, and fuel additives. A recent mass flow modeling study predicted that a major source of CeO2 nanoparticles from industrial processing plants (e.g., electronics and optics manufactures) is likely to reach the terrestrial environment such as landfills and soils. The environmental fate of CeO2 nanoparticles is highly dependent on its physcochemical properties in low temperature geochemical environment. Though there are needs in improving the analytical method in detecting/quantifying CeO2 nanoparticles in different environmental media, it is clear that aquatic and terrestrial organisms have been exposed to CeO2 NPs, potentially yielding in negative impact on human and ecosystem health.