Sediment biobarriers for chlorinated aliphatic hydrocarbons in groundwater reaching surface water

Kelly Hamonts, Miranda Maesen, Annemie Ryngaert, Johan Vos, Richard Lookman, Jan Bronders, Winnie Dejonghe, John Dijk, Dirk Springael, Mark Sturme, Hauke Smidt, Jan Kuklik, Petr Kozubek, Thomas Kuhn, Rainer Meckenstock, Thomas Lange, Harald Kalka, Niels Holger Peters, Jörg Perner, Lutz Eckardt

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

In the EU-project SEDBARCAH the intrinsic capacity of eutrophic river sediment microbial communities to degrade Chlorinated Aliphatic Hydrocarbons (CAHs) was studied. As a test case, the Bìlá river in Czech Republic and the Zenne river in Belgium were chosen. For both rivers the influx zones of the CAHs were determined over a length of 45 m by sampling groundwater in boreholes, river sediment using a piston sampler and interstitial water of the sediment using a specific pore water probe. The CAH concentrations found indicated that the groundwater discharge spatial distribution is very heterogeneous, mostly depending on local sediment permeability. At some locations in the riverbed full dechlorination was observed while VC and cis-DCE reach the surface water and seem to discharge into the river at spots with a high velocity groundwater influx. Hydrogen and oxygen isotope analysis of the groundwater, surface water and sediment pore water confirmed the spatial heterogeneity of the groundwater influx zones while Compound Specific Isotope analyses of CAHs indicated that microbial degradation of the groundwater pollutants is taking place in the sediments. The CAH influx in the Zenne river was constant during 2 years of monitoring in which groundwater, pore water and surface water samples were taken monthly and no seasonal variations in the microbial degradation potential could be detected. At the highest CAH influx zones, undisturbed sediment samples were taken with a piston sampler to further study the structure and the catabolic potential of the microbial community. Anaerobic microcosm and column degradation tests showed, for both rivers, a rapid microbial dehalogenation of all CAH compounds to non-toxic ethene. For the Zenne river, chloroethene degrading Desulfuromonas and Dehalococcoides species were present in high numbers in the sediment as shown by quantification of their 16S rRNA genes by real-time PCR. Furthermore, the quantification of the vcrA and bvcA genes, which code for the VC reductive dehalogenases of respectively Dehalococcoides sp. strain VS and BAV1 indicates that these two Dehalococcoides species are probably responsible for the observed degradation of VC, the main pollutant in the Zenne. This high microbial CAH degradation potential was not present in the aquifer upstream of the river Zenne, but could be stimulated by adding a carbon source such as lactate or molasses, or an extract of the river sediment. Our results indicate that the interface between groundwater and surface water harbors a unique microbial community structure that is capable of degrading CAHs in groundwater before they reach the surface water.

Original languageEnglish
Title of host publicationIn Situ and On-Site Bioremediation-2009
Subtitle of host publicationProceedings of the 10th International In Situ and On-Site Bioremediation Symposium
StatePublished - 2009
Externally publishedYes
Event10th International In Situ and On-Site Bioremediation Symposium, In Situ and On-Site Bioremediation-2009 - Baltimore, MD, United States
Duration: 5 May 20098 May 2009

Publication series

NameIn Situ and On-Site Bioremediation-2009: Proceedings of the 10th International In Situ and On-Site Bioremediation Symposium

Conference

Conference10th International In Situ and On-Site Bioremediation Symposium, In Situ and On-Site Bioremediation-2009
Country/TerritoryUnited States
CityBaltimore, MD
Period5/05/098/05/09

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