Browsing by Subject "Remediation"

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Open Access
A Survey of Fungal Community Composition along a Gradient of Recovery on the Mine Sites in the Carolinas
(2019-05-06) Miao, Ruolin
In the era of Anthropocene, an increasing part of the terrestrial environments is losing their ecosystem services and function, negatively affecting both human economics and the ecological system. Phytoremediation, the use of plants to reverse degradation and to restore ecological function, has been a promising approach. However, the symbiotic soil microbiota that influence the effectiveness of this method is not fully understood. I sampled the soil and roots of Pinus spp. (pines) at four sites along a gradient of vegetation recovery on the Superfund Site Brewer Gold Mine (SC), the Henry Knob Mine (SC), and Russell Gold Mine. The acidity, nutrient profile and heavy-metal contamination of collected soil is determined. DNA is extracted from the soil and root samples with PowerSoil DNA Isolation Kit, followed by preparation of multiplex PCR samples of the ITS region. Sequence reads generated through Illumina Miseq is processed through QIIME pipeline and taxonomy assigned through UNITE database. The results show a pattern of succession in fungal communities along a recovery gradient. While the mycorrhizal fungi on the least recovered site are dominated by Rhizopogon sp. and Pisolithus sp., sites with more recovered vegetation reveal a more diverse array of symbiotic fungi, including Amanita sp. and Russula sp.. These diverse fungi, although came later in the succession pattern, likely brings more diverse benefits to help their hosts cope with the stressful environment. This “bioprospecting” method could be applied to extract and amplify symbiotic fungi to facilitate revegetation efforts.
Open Access
Examining the Feasibility of using Coal Mine Drainage as a Hydraulic Fracturing Fluid
(2013-04-26) Kondash, Andrew
Much of the current concern about hydraulic fracturing revolves around the treatment and disposal of wastewaters that come up out of the well after fracturing has occurred. These “produced waters” and “flowback waters” in some cases are high in concentrations of total dissolved solids (TDS), naturally occurring radioactive material (NORM), and metals. There are currently many ways these wastewaters are managed including being recycled on site, treated at commercial waste water treatment plants, or shipped away for storage in federally permitted underground injection wells. This study suggests that by supplementing wastewater with high-sulfate coal mine drainage (CMD), on site recycling can be even more effective through the removal of high metal concentrations and NORM from the wastewater. This could potentially allow for 100% waste water recycling, saving local water resources, while a legacy environmental problem may be remediated. This study was focused on the idea that by mixing coal mine drainage with flowback or produced water, many of the negative characteristics of both fluids can be remediated. The sulfate can be removed from the coal mine drainage, and with it, the barium and radium can be removed from the coal mine drainage. Mix ratios of 1:4, 1:2, and 3:4 were used for this study and in almost every case a majority of the radium (100% for each ratio), barium (75, 90, and 80% respectively), and sulfate (90, 75, and 40% respectively) precipitated out of the mixture. Barium and radium concentrations were found to be strongly correlated within each the sample (r2 of .815). In addition to that, the removal of those solutes was also found to be correlated (r2 of .75). Finally, using spatial analysis and a number of input factors, it was found that on average the use of coal mine drainage is between $30 and $200 thousand more expensive to use per well than fresh water. These results indicate that mixing AMD and flowback water is an effect means of water treatment for re-use as hydraulic fracturing fluid. Although not currently cost effective, the potential to clean up a legacy environmental problem has inspired policy makers to begin the process of making the use of coal mine drainage more cost effective with less legal consequence.
Open Access
Fate, Transport and Toxicity of Nanoscale Zero-Valent Iron (nZVI) Used During Superfund Remediation
(2010-04-29T17:38:25Z) Keane, Emily
As a result of the Superfund Amendments and Reauthorization Act (SARA) of 1986, the United States Environmental Protection Agency (EPA) has increased consideration and implementation of newer and more efficient innovative technologies to treat wastes rather than the traditional “dig-and-haul” and “pump-and-treat” methods for removing contaminated soils and groundwater from the site (U.S. EPA 2008b). One such emerging field that holds potential for cleaning up Superfund sites in a more cost effective and efficient manner is nanotechnology. The impacts of nanotechnology are increasingly evident in all areas of science and technology, including the field of environmental studies and treatment. Experts anticipate the development and implementation of environmentally beneficial nanotechnologies in the categories of sensing and detecting, pollution prevention, and treatment and remediation. Of the three, the category of treatment and remediation has experienced the most growth in recent years. In terms of site remediation, the development and deployment of nanotechnology for contaminant destruction has already taken place. Nanoscale zero-valent iron (nZVI) particles and the subsequent derivatives (bimetallic iron particles and emulsified iron) represent a viable, commercially available nanotechnology for in situ remediation at Superfund and other contaminated sites. Responsible use of nZVI in environmental applications and careful management of the associated risks requires a fundamental understanding of their mobility, potential bioavailability/bioaccumulation and impacts on a wide variety of organisms. Currently this fundamental understanding of the environmental fate of nZVI and its oxidation products is not well understood for the variety of environmental conditions that may occur. In general, the high tendency of bare nZVI to agglomerate indicates that migration in the groundwater should not be an issue for groundwater drinking wells, streams and other bodies of water. This agglomeration will also limit the risk of human and environmental exposure to nZVI used for remediation. Issues, however, may exist for organisms in the environment that are directly exposed to the nZVI before much oxidation of the particles takes place. Concerns may also exist with incomplete conversion of certain contaminants and the offsite mobilization of contaminants that bind to the nZVI. Understanding the fate, transport and toxicity of nZVI in its early phases of use is essential before the technology can be used on a large scale.