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Fate of microbial metabolites of hydrocarbons in a coastal plain aquifer: The role of electron acceptors

January 1, 1995

A combined field and laboratory study was undertaken to understand the distribution and geochemical conditions that influence the prevalence of low molecular weight organic acids in groundwater of a shallow aquifer contaminated with gasoline. Aromatic hydrocarbons from gasoline were degraded by microbially mediated oxidation-reduction reactions, including reduction of nitrate, sulfate, and Fe(III). The biogeochemical reactions changed overtime in response to changes in the hydrogeochemical conditions in the aquifer. Aliphatic and aromatic organic acids were associated with hydrocarbon degradation in anoxic zones of the aquifer. Laboratory microcosms demonstrated that the biogeochemical fate of specific organic acids observed in groundwater varied with the structure of the acid and the availability of electron acceptors. Benzoic and phenylacetic acid were degraded by indigenous aquifer microorganisms when nitrate was supplied as an electron acceptor. Aromatic acids with two or more methyl substituants on the benzene ring persisted under nitrate-reducing conditions. Although iron reduction and sulfate reduction were important processes in situ and occurred in the microcosms, these reactions were not coupled to the biological oxidation of aromatic organic acids that were added to the microcosms as electron donors. 

Citation Information

Publication Year 1995
Title Fate of microbial metabolites of hydrocarbons in a coastal plain aquifer: The role of electron acceptors
DOI 10.1021/es00002a023
Authors I.M. Cozzarelli, J.S. Herman, M. Jo Baedecker
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science & Technology
Index ID 70018740
Record Source USGS Publications Warehouse
USGS Organization Toxic Substances Hydrology Program