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BIOMASS ACCUMULATION AT THE ELIZABETH CITY AND DENVER FEDERAL CENTER PRBS
Citation:
Wilkin*, R T. BIOMASS ACCUMULATION AT THE ELIZABETH CITY AND DENVER FEDERAL CENTER PRBS. Presented at Interstate Technology Regulatory Cooperation Training, 10/23-25/2001.
Description:
Microbial characterization results, based on PLFA profiles, from the Elizabeth City PRB and adjacent aquifer materials showed a diverse microbiological community dominated by Gram-negative bacteria. Iron core samples from near the upgradient edge of the PRB are typically enriched in microbial biomass (up to 5.23x107 cells/g) and contained elevated proportions of biomarkers indicative of metal-reducing and sulfate-reducing bacteria. Aquifer materials (up to 6.96x106 cells/g) and iron from near the downgradient PRB edge (5.20x106 cells/g) were comparatively depleted in total biomass and in biomarkers indicative of metal-reducing and sulfate-reducing bacteria. Microbiological results, based on PLFA analyses, indicate enriched biomass in gate 2 of the Denver Federal Center (up to 9.85x107 cell/g). Biomass concentrations in gate 2 were a factor of about 2x greater compared to gates 1 and 3, and the Elizabeth City PRB. The higher biomass concentrations may be linked to low-flow conditions in the gate and high sulfate concentrations. Concentrations of iron sulfide precipitates are also comparatively high in gate 2 of the DFC (up to 5650 g/g). Gram-negative bacteria dominate the microbial community. Present in the iron samples are elevated proportions of biomarkers indicative of metal-reducing and sulfate-reducing bacteria.
