Environmental interfaces come in many varieties, including solid-water, solid-gas, solid-microbial bifofilm-water, solid-organic film-water, etc., and they exist under a variety of conditions, none of which involve UHV. In addition, the solids involved in environmental interfaces are often in the nanoparticle size range, which may result in properties, such as surface structures and reactivities, that differ from their bulk counterparts. Another common complication is that the surfaces of environmental solids are often coated by natural organic matter and/or microbial biofilms, which could have dramatic effects on their surface charge properties, extent of aggregation, and reactivity. In contrast, most surface science studies involve clean single crystal surfaces on which metals, molecules, or organic molecules are attached under carefully controlled conditions, typically involving UHV. In order to increase our understanding of the chemical and biological processes at environmental interfaces, the pressure, cleanliness, and size gaps must be overcome to the extent possible in surface science studies. We will discuss recent near-ambient pressure XPS studies of the interfaces between alpha-Fe2O3 (0001) and water and Fe3O4 and water, which have revealed the extent of dissociation of water and hydroxylation of these surfaces. We will also present the results of new x-ray standing wave fluorescence yield spectroscopy studies of the interaction of aqueous metal ions with alpha-Fe2O3 nanoparticles coated by polyacrylic acid and natural organic matter thin films as well as with microbial biofilm-coated single crystal metal oxides. The results of these studies have revealed that the intrinsic order of reactivities of different metal oxide surfaces coated by organic matter or microbial biofilms is not affected by the coatings. However, time-dependent studies have shown that the rates of partitioning of metal ions between aqueous solutions and metal oxide surfaces are diffusion controlled. Finally, we will discuss differences in surface structures of nanoparticulate (avg. diameter = 10 nm) vs. microparticulate (avg. diameter = 550 nm) of alpha-Fe2O3 derived from XAFS spectroscopy studies of Zn(II) ions sorbed on the particle surfaces.