Nanoparticles of Al2O3 are in commercial scale production for use in a wide variety of medicinal and skin care products. The increase in production could lead to the introduction of those nanoparticles to soils and aquatic environments, affecting biogeochemical processes of ecological importance. The objective of this study is to evaluate the mobility, transformation and potential effects of aluminum nanoparticles (ANP) on certain microbial mediated soil processes. First, a physical and chemical characterization of the nanoparticles will be performed and results compared to those obtained from naturally occurring aluminum hydroxides. Data obtained will be related to mobility, complexation with organic, inorganic and /or biotic components and adsorption parameters of the ANP. Second, the effect of ANP on anaerobic microbial C cycling in anaerobic soils will be evaluated. Preliminary laboratory incubation studies suggest variable concentration of ANP significantly increased methanogenesis rates and affected anaerobic carbon dioxide production rate in a wetland soil. Further studies will elucidate this effect and put forward possible explanations. Results from this overall study will help answer whether metal oxide nanoparticles will pose an immediate threat to soil and soil microbial populations.