부산대학교 도서관

A comprehensive model was applied to simulate a laboratory microcosm study of biodegradation rates and the branched production and loss of daughter products. The aim of the investigation was to evaluate the effect of electron donors (lactate, ethanol, and natural organic matter) on 2,4,6-trinitrotoluene (TNT) biodegradation rate and pathway in historically contaminated sediments undergoing biostimulation. Simulation results show overall TNT degradation rates for lactate-amended microcosms were greater than ethanolamended microcosms by a factor of 1.7 and 3.0 times compared with natural organic matter amended microcosms. Differences in observed biomass concentrations (lactate > ethanol > unamended) were thought to be a contributing factor. TNT degradation pathway modeling included determination of branching coefficients representing whether the first nitro group reduction occurred in the ortho or para position. Branching coefficients were greater for the initial reduction of para (17-27% initial TNT concentration) over ortho (3-9% initial TNT concentration) for all test conditions. However, greater degradate recovery and a different (lower para:ortho) ratio was observed for ethanol compared with lactate and unamended conditions. Given the variation in sorption parameters among degradate isomers, these results suggest that differences in pathway branching stimulated by different electron donors are potentially relevant to the long-term persistence of TNT degradation products and the ultimate success of bioremediation-based remedial strategies. [ABSTRACT FROM AUTHOR]