title: Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms.
abstract: Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [(13)C6]-ETBE (BACTRAP(®)s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant (13)C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation.
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig, Germany; Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig, Germany. Electronic address: petra.bombach@ufz.de.
authors.forename: Petra
authors.initials: P
authors.lastname: Bombach
authors.affiliation: Kuvier the Biotech Company S.L., Ctra. N-I, p.k. 234-P.E. INBISA 23ª, E-09001 Burgos, Spain.
authors.forename: Norbert
authors.initials: N
authors.lastname: Nägele
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig, Germany; Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), C/Martí i Franquès s/n, 08028 Barcelona, Spain.
authors.forename: Mònica
authors.initials: M
authors.lastname: Rosell
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig, Germany.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Richnow
authors.affiliation: Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig, Germany.
authors.forename: Anko
authors.initials: A
authors.lastname: Fischer
mesh_terms: D001673:Biodegradation, Environmental; D002247:Carbon Isotopes / Q000032:analysis*; D005591:Chemical Fractionation; D004784:Environmental Monitoring / Q000379:methods*; D005019:Ethyl Ethers / Q000032:analysis*; D005227:Fatty Acids / Q000737:chemistry; D060587:Groundwater; D006859:Hydrogen / Q000032:analysis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008738:Methyl Ethers / Q000032:analysis; D009930:Organic Chemicals / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002247:Carbon Isotopes; D005019:Ethyl Ethers; D005227:Fatty Acids; D008738:Methyl Ethers; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; C098546:ethyl tert-butyl ether; D006859:Hydrogen; D010100:Oxygen
keywords: Compound-specific stable isotope analysis (CSIA); ETBE biodegradation; Groundwater remediation; In situ microcosm (BACTRAP); Total lipid fatty acid-stable isotope probing (TLFA-SIP)