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

Environmental Science & Technology
By: , and 

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Abstract

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. 

Publication type Article
Publication Subtype Journal Article
Title Fate of microbial metabolites of hydrocarbons in a coastal plain aquifer: The role of electron acceptors
Series title Environmental Science & Technology
DOI 10.1021/es00002a023
Volume 29
Issue 2
Year Published 1995
Language English
Publisher ACS
Contributing office(s) Toxic Substances Hydrology Program
Description 12 p.
First page 458
Last page 469
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