Juliette N. Rooney-Varga Catherine V. Gaw Derek R. Lovley Robert T. Anderson 1998 <div class="article_abstract"><div class="container container_scaled-down"><div class="row"><div class="col-xs-12"><div id="abstractBox" class="article_abstract-content hlFld-Abstract"><p class="articleBody_abstractText">The potential for anaerobic benzene oxidation in the Fe(III)-reduction zone of petroleum-contaminated aquifers was evaluated. Sediments were incubated under strict anaerobic conditions without any amendments in order to simulate in situ conditions. [¹⁴C]Benzene was not oxidized to<span>&nbsp;</span>¹⁴CO₂<span>&nbsp;</span>at most sites examined, which is consistent with previous studies that have found that benzene tends to persist in unamended, anaerobic aquifer materials and/or long periods of time are required in order to adapt the microbial population for benzene degradation. However, at one site located in Bemidji, MN, [¹⁴C]benzene was oxidized to<span>&nbsp;</span>¹⁴CO₂<span>&nbsp;</span>in unamended sediments without an apparent lag, suggesting that benzene was anaerobically degraded in situ. Benzene was not significantly oxidized in sediments from nearby Fe(III)-reducing sites nor in sediments collected from an uncontaminated background site in the same aquifer. Culturing and 16S rRNA-based molecular studies of the Bemidji aquifer demonstrated that while all sites contained similar numbers of Fe(III)-reducing microorganisms closely related to<span>&nbsp;</span><i>Geothrix fermentens</i>, the site at which anaerobic benzene degradation was observed was greatly enriched with microorganisms in the family<span>&nbsp;</span><i>Geobacteraceae</i>. This study provides the first data consistent with in situ anaerobic oxidation of benzene to carbon dioxide in the Fe(III)-reducing zone of a petroleum-contaminated aquifer and suggests that comparative studies on the size of the<span>&nbsp;</span><i>Geobacteraceae</i><span>&nbsp;</span>community in petroleum-contaminated aquifers might aid in the location of zones in which benzene degradation coupled to Fe(III) reduction is taking place.</p></div></div></div></div></div> application/pdf 10.1021/es9704949 en American Chemical Society Anaerobic benzene oxidation in the Fe(III) reduction zone of petroleum-contaminated aquifers article