Comparison of Microporous Minerals for Potential Contaminant Uptake

<p>Microporous minerals have many industrial applications, from filtration to contaminant immobilization. Natural and synthetic minerals, including zeolites, clays, and silica aerogel, represent a few examples of microporous minerals with distinctive structures, surface charges, and porosity. Analysis and comparison of their crystal structures are necessary to determine how each mineral may be suited for contaminant uptake. Here we assessed the structure of microporous minerals, specifically rowleyite, clinoptilolite, vermiculite, and silica aerogel.  Raman spectroscopy, X-ray fluorescence, and X-ray powder diffraction were used to create and model atomic mineral structures to visualize atomic and macroscope features. Taking into account pore size and surface charge each mineral was reviewed to find the best fit with regards to heavy metal uptake, mainly Pb (lead). Overall, we provide a comparative framework to assess microporous minerals that will inform future flow-through experiments for heavy metal uptake.</p>

Urban Stream Syndrome and Contaminant Uptake in Salamanders of Central Texas

We studied the ecological health of springs experiencing varying levels of urban development to assess impacts to rare endemic salamanders (Eurycea spp.) of Central Texas. We evaluated measures of invertebrate species richness, water quality, and contaminant uptake by salamanders to determine how springs and their inhabitants were being affected by urban growth and changing land-use patterns. The number of environmental contaminants present and concentrations of contaminants increased in both water and salamander tissues with increasing age of the developments (i.e., years postconstruction) and increasing levels of impervious cover (e.g., roads) in urban watersheds compared with nondeveloped sites. We conclude that urbanization and associated increases in pollutant loading in watersheds can result in a loss of spring biodiversity and the accumulation of persistent and potentially toxic pollutants in salamanders. Although we detected generally low levels of pollutants, the altered water quality and invertebrate composition observed at springs, coupled with the changing hydrology and chronic contaminant exposure inherent in urban landscapes, is cause for concern, with potential implications for the long-term health, survival, and recovery of salamanders.