Metal oxide nanoparticles are a form of pollution generated by a number of industrial procedures, and there is evidence that this class of nanoparticle can have a detrimental effect on human health and ecology. The chemical properties of nanoparticles are primarily influenced by the nature of their surfaces. However, surface water is an inherent component of metal oxides nanoparticle systems, and therefore if we are to obtain a comprehensive understanding of the chemical and physical properties of these nanoscale pollutants it is imperative that the thermodynamic properties of these hydration layers be evaluated. In particular, we wish to study 8-15nm samples of hydrated Fe2O3, ZnO, CuO, MoO2, and CeO2. The toxicities of Fe2O3, ZnO, and CeO2 particles are known to be of significance, and we are including CuO, MoO2 in this study due to the known aquatic toxicity of Cu and Mo metal ions.