Type of Document Master's Thesis Author Boncal, Janelle Elizabeth URN etd-02172011-134222 Title Spatial Relationships Between Potential Bioavailable Organic Carbon and Sediment Grain Size at a Chlorinated Solvent-Contaminated Site Degree Master of Science Department Civil Engineering Advisory Committee
Advisor Name Title Widdowson, Mark A. Committee Chair Little, John C. Committee Member Novak, John T. Committee Member Keywords
- potential bioavailable organic carbon
- grain size
- hydraulic conductivity
- chlorinated solvents
Date of Defense 2011-02-03 Availability unrestricted AbstractChlorinated ethenes are considered one of the most prevalent sources of groundwater contamination in developed countries. Natural attenuation of chlorinated ethenes is possible through the process of microbial reductive dechlorination. Reductive dechlorination can occur in contaminated aquifers where there are sufficient amounts of organic carbon and reducing redox conditions to support dechlorinating microorganisms. Natural organic carbon (NOC) from dissolved aquifer sediment is thought to be the source of fermentable compounds needed to produce molecular hydrogen that functions as the primary electron donor for reductive dechlorination. Therefore, in an anaerobic aquifer, the production of molecular hydrogen from the fermentation of NOC drives the reductive dechlorination process.
The variability and distribution of potential bioavailable organic carbon (PBOC) at a site is relatively unknown and any potential relationships between PBOC and the physical properties of the aquifer sediment have not been evaluated. Exploring relationships between the grain size of aquifer sediment PBOC may help to determine the feasibility of natural attenuation as a long-term remediation strategy at chlorinated ethene-contaminated sites. Because hydraulic conductivity is directly related to aquifer sediment grain size, zones of high hydraulic conductivity may promote greater microbial activity or biodegradation because of the increased availability of PBOC and nutrient flux.
To determine potential relationships between PBOC and aquifer sediment grain size, two experiments were performed. PBOC was measured for 106 sediment samples impacted by chlorinated solvent contamination from an anaerobic type II site through a multiple liquid extraction process (Rectanus et al. 2007). Grain size distributions for each of the 106 sediment samples were determined by conducting sieve analyses. The results of both experiments were compared to explore relationships between PBOC and sediment grain size and to evaluate spatial distribution of both in the surficial aquifer.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access Boncal_JE_T_2011.pdf 1.24 Mb 00:05:45 00:02:57 00:02:35 00:01:17 00:00:06
If you have questions or technical problems, please Contact DLA.