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Natural Anaerobic Biodegradation of TBA in Aquifer Sediments at Gasoline Spill Sites
Citation:
WILSON, J. T., C. J. ADAIR, AND H. WHITE. Natural Anaerobic Biodegradation of TBA in Aquifer Sediments at Gasoline Spill Sites. Presented at 20th Annual National Tanks Conference, Atlanta, GA, March 17, 2008.
Impact/Purpose:
To evaluate the role of sulfate reducing bacteria in the natural biodegradation of TBA at gasoline spill sites.
Description:
TBA is an important contaminant at spills sites of gasoline that contains MTBE. The impact of TBA is particularly important in Southern California, where the State Action Level for TBA is 12 μg/L and many communities produce ground water for drinking water from an urban landscape. Concentrations of TBA in ground water at gasoline spill sites are equal to or greater than concentrations of MTBE (Figure 1). At many gasoline spill sites, MTBE is present at higher concentrations immediately after the spill. Then the microbial community acclimates to degrade MTBE to TBA, and TBA is present at higher concentrations (Figure 2). To evaluate the role of sulfate reducing bacteria in the natural biodegradation of TBA at gasoline spill sites, microcosms were constructed from five sites in Southern California. To protect anaerobic bacteria that might degrade TBA, the microcosms were constructed in an anaerobic glove box (Figure 3 and Figure 4). Some of the microcosms were amended with biobeads that were baited with TBA. Some just had TBA and no biobeads. Microcosms were constructed with sediment samples from three gasoline service stations, from seven sediment samples from a distribution terminal in San Diego, CA, and from two sediment samples from a distribution terminal in South Gate, CA.