The purpose of this report is to present the findings of a literature review and personal interviews about the ecology and geology of the Mississippi river gorge located on the eastern boarder of the Seward neighborhood. The directives were to study both the history and current conditions of the geology and ecology of the Mississippi river gorge in Seward. The report was commissioned to aid the Seward Neighborhood Group (SNG) in producing a brochure that describes these features of the Riverside Park.
<p>Rare earth elements (REEs) are an emerging pollutant whose increasing use in various technological applications causes increasing risk of environmental contamination. Electronic waste (E-waste) could be one major source of REE pollution, as E-waste typically contains elevated REE concentrations and is often handled in unsafe and environmentally hazardous ways. Here, a series of leaching assays revealed that <1% of REEs available in a representative E-waste were released except at acidic conditions (pH 2) rarely observed in nature. If REEs are leached from E-waste, the extent of their spread in the environment will depend, in large part, on their mobility through porous media. Measurements of REE transport through saturated sand demonstrated extremely limited mobility except at acidic conditions (pH 2), though significant REE retention by the substrate still occurs at this low pH. Similar experiments in a natural soil found REE mobility to be even lower in that substrate, with complete REE retention even after the passage of up to 215 pore volumes of a 500 ppb REE solution. Aqueous REEs are therefore not expected to be highly mobile in the environment. The presence of natural or anthropogenic nanoparticles may affect REE behavior during leaching and/or transport. Measurements indicated that silica nanoparticles can increase the concentration of fluid-mobile REEs during E-waste leaching, but both plastic and silica nanoparticles have a negligible effect on REE transport. Ultimately, the experiments and analysis presented here suggest that the threat of REE pollution from E-waste is minimal except at specific sites with unusual environmental conditions.</p>