Mònica Rosell | Universitat de Barcelona (original) (raw)

Papers by Mònica Rosell

Chromatographia, 2002

Heacl space gas chromatography with flame-ionization detection (HS-GC-FID), ancl purge and trap g... more Heacl space gas chromatography with flame-ionization detection (HS-GC-FID), ancl purge and trap gas chromatography-mass spectrometry (P&T-GC-MS) have been used to determine methyl-tert-butyl ether (MTBE) and benzene, toluene, and the xylenes (BTEX) in groundwater. In the work discussed in this paper measures of quality, e.g. recovery (94-111%), precision (4.6-12.2%), limits of detection (0.3-5.7 I~g L 1 for HS and 0.001 I~g L 1 for PT), and robustness, for both methods were compared. In addition, for purposes of comparison, groundwater samples from areas suffering from odor problems because of fuel spillage and tank leakage were analyzed by use of both techniques. For high concentration levels there was good correlation between results from both methods. Results from P&T analysis showed that 20 of the 21 samples from the vulnerable areas contained MTBE at concentrations up to 666 I~g L 1. Levels in seven samples exceeded maximum permissible levels for odor and taste set by the USEPA (20-40 I~g L 1); for thirteen of the samples levels were bel',,veen 0.28 and 179 I~g L 1. The sensitivily of HS-GC-FID was, however, I',,vo to three orders of magnitude lower and concentrations of 6-10 I~g L 1 could not always be detected, leading to false negatives. The same behavior was observed for analysis of BTEXthe lower sensitivity of HS-GC-FID and coelution of peaks led to results of poor rehabihty, and confirmation by GC-MS was always necessary. The applicability of I',,vo analytical methods widely used for routine monitoring of VOC thus depends on the organoleptic thresholds of MTBE and BTEX in groundwater (20 I~g L 1) and the need to survey trace concentrations of persistent MTBE in vulnerable aquifers.

Water Research

Based on the previously observed intrinsic bioremediation potential of a site originally contamin... more Based on the previously observed intrinsic bioremediation potential of a site originally contaminated with perchloroethene (PCE), field-derived lactate-amended microcosms were performed to test different lactate isomers and concentrations, and find clearer isotopic and molecular parameters proving the feasibility of an in-situ enhanced reductive dechlorination (ERD) from PCE-to-ethene (ETH). According to these laboratory results, which confirmed the presence of Dehalococcoides sp. and the vcrA gene, an in-situ ERD pilot test consisting of a single injection of lactate in a monitoring well was performed and monitored for 190 days. The parameters used to follow the performance of the ERD comprised the analysis of i) hydrochemistry, including redox potential (Eh), and the concentrations of redox sensitive species, chlorinated ethenes (CEs), lactate, and acetate; ii) stable isotope composition of carbon of CEs, and sulphur and oxygen of sulphate; and iii) 16S rRNA gene sequencing from groundwater samples. Thus, it was proved that the injection of lactate promoted sulphate-reducing conditions, with the subsequent decrease in Eh, which allowed for the full reductive dechlorination of PCE to ETH in the injection well. The biodegradation of CEs was also confirmed by the enrichment in 13 C and carbon isotopic mass balances. The metagenomic results evidenced the shift in the composition of the microbial population towards the predominance of fermentative bacteria. Given the success of the in-situ pilot test, a full-scale ERD with lactate was then implemented at the site. After one year of treatment, PCE and trichloroethene were mostly depleted, whereas vinyl chloride (VC) and ETH were the predominant metabolites. Most importantly, the shift of the carbon isotopic mass balances towards more positive values confirmed the complete reductive dechlorination, including the VC-to-ETH reaction step. The combination of techniques used here provides complementary lines of evidence for the diagnosis of the intrinsic biodegradation potential of a polluted site, but also to monitor 3 the progress, identify potential difficulties, and evaluate the success of ERD at the field scale.

Science of The Total Environment

Many aquifers around the world are impacted by toxic chlorinated methanes derived from industrial... more Many aquifers around the world are impacted by toxic chlorinated methanes derived from industrial processes due to accidental spills. Frequently, these contaminants co-occur with chlorinated ethenes and/or chlorinated benzenes in groundwater, forming complex mixtures that become very difficult to remediate. In this study, a multi-method approach was used to provide lines of evidence of natural attenuation processes and potential setbacks in the implementation of bioremediation strategies in multi-contaminated aquifers. First, this study determined i) the carbon and chlorine isotopic compositions (δ 13 C, δ 37 Cl) of several commercial pure phase chlorinated compounds, and ii) the chlorine isotopic fractionation (εCl =-5.2 ± 0.6‰) and the dual C-Cl isotope correlation (Λ C/Cl = 5.9 ± 0.3) during dichloromethane (DCM) degradation by a Dehalobacteriumcontaining culture. Such data provide valuable information for practitioners to support the interpretation of stable isotope analyses derived from polluted sites. Second, the bioremediation potential of two industrial sites contaminated with a mixture of organic pollutants (mainly DCM, chloroform (CF), trichloroethene (TCE), and monochlorobenzene (MCB)) was evaluated. Hydrochemistry, dual (C-Cl) isotope analyses, laboratory microcosms, and microbiological data were used to investigate the origin, fate and biodegradation potential of chlorinated methanes. At Site 1, δ 13 C and δ 37 Cl compositions from field samples were consistent with laboratory microcosms, which showed complete degradation of CF, DCM and TCE, while MCB remained.

E3S Web of Conferences

We used C-Cl dual isotope analysis and microcosm studies for elucidating the origin and fate of t... more We used C-Cl dual isotope analysis and microcosm studies for elucidating the origin and fate of the common groundwater pollutant dichloromethane (DCM) in two different multi-contaminant field sites in Catalonia, Spain; where DCM contamination could be the result of direct solvent releases and/or chloroform (CF) transformation. Known commercial solvents isotopic compositions as well as characteristic C-Cl dual isotope slopes from our anaerobic enrichment culture containing Dehalobacterium sp., capable of fermenting DCM, and other bacteria from the literature were used for field data interpretation.

Environmental Pollution

The bioremediation potential of an aquifer contaminated with tetrachloroethene (PCE) was assessed... more The bioremediation potential of an aquifer contaminated with tetrachloroethene (PCE) was assessed by combining hydrogeochemical data of the site, microcosm studies, metabolites concentrations, compound specific-stable carbon isotope analysis and the identification of selected reductive dechlorination biomarker genes. The characterization of the site through 10 monitoring wells evidenced that leaked PCE was transformed to TCE and cis-DCE via hydrogenolysis. Carbon isotopic mass balance of chlorinated ethenes pointed to two distinct sources of contamination and discarded relevant alternate degradation pathways in the aquifer. Application of specific-genus primers targeting Dehalococcoides mccartyi species and the vinyl chloride-to-ethene reductive dehalogenase vcrA indicated the presence of autochthonous bacteria capable of the complete dechlorination of PCE. The observed cis-DCE stall was consistent with the aquifer geochemistry (positive redox potentials; presence of dissolved oxygen, nitrate, and sulphate; absence of ferrous iron), which was thermodynamically favourable to dechlorinate highly chlorinated ethenes but required lower redox potentials to evolve beyond cis-DCE to the innocuous end product ethene. Accordingly, the addition of lactate or a mixture of ethanol plus methanol as electron donor sources in parallel field-derived anoxic microcosms accelerated dechlorination of PCE and passed cis-DCE up to ethene, unlike the controls (without amendments, representative of field natural attenuation). Lactate fermentation produced acetate at near-stoichiometric amounts. The array of techniques used in this study provided complementary lines of evidence to suggest that enhanced anaerobic bioremediation using lactate as electron donor source is a feasible strategy to successfully decontaminate this site.

The Science of the total environment, Jan 16, 2018

The effects of contaminant sources removal in 2005 (i.e. barrels, tank, pit and wastewater pipe s... more The effects of contaminant sources removal in 2005 (i.e. barrels, tank, pit and wastewater pipe sources) on carbon tetrachloride (CT) and chloroform (CF) concentration in groundwater were assessed at several areas of a fractured multi-contaminant aquifer (Òdena, Spain) over a long-term period (2010-2014). Changes in redox conditions, in these chlorinated methanes (CMs) concentration and in their carbon isotopic compositions (δC) were monitored in multilevel wells. δC values from these wells were compared to those obtained from sources (barrels, tank and pit before their removal, 2002-2005) and to commercial solvents values in literature. Additionally, CMs natural attenuation processes were identified by C-Cl isotope slopes (Λ). Analyses revealed the downstream migration of the pollutant focus and an efficient removal of DNAPLs in the pit source's influence area. However, the removal of the contaminated soil from former tank and wastewater pipe was incomplete as leaching from uns...

The Science of the total environment, Jan 6, 2018

Chlorinated ethanes are frequent groundwater contaminants but compound specific isotope analysis ... more Chlorinated ethanes are frequent groundwater contaminants but compound specific isotope analysis (CSIA) has been scarcely applied to investigate their degradation pathways. In this study, dual carbon and chlorine isotope fractionation was used to investigate for the first time the anoxic biodegradation of 1,1,2-trichloroethane (1,1,2-TCA) using a Dehalogenimonas-containing culture. The isotopic fractionation values obtained for the biodegradation of 1,1,2-TCA were ɛ = -6.9 ± 0.4‰ and ɛ = -2.7 ± 0.3‰. The detection of vinyl chloride (VC) as unique byproduct and a closed carbon isotopic mass balance corroborated that dichloroelimination was the degradation pathway used by this strain. Combining the values of δC and δCl resulted in a dual element C-Cl isotope slope of Λ = 2.5 ± 0.2‰. Investigation of the apparent kinetic isotope effects (AKIEs) expected for cleavage of a CCl bond showed an important masking of the intrinsic isotope fractionation. Theoretical calculation of Λ suggested ...

Chemosphere, Jan 7, 2018

A dual element CCl isotopic study was performed for assessing chlorinated methanes (CMs) abiotic ... more A dual element CCl isotopic study was performed for assessing chlorinated methanes (CMs) abiotic transformation reactions mediated by iron minerals and Fe(0) to further distinguish them in natural attenuation monitoring or when applying remediation strategies in polluted sites. Isotope fractionation was investigated during carbon tetrachloride (CT) and chloroform (CF) degradation in anoxic batch experiments with Fe(0), with FeCl(aq), and with Fe-bearing minerals (magnetite, Mag and pyrite, Py) amended with FeCl(aq), at two different pH values (7 and 12) representative of field and remediation conditions. At pH 7, only CT batches with Fe(0) and Py underwent degradation and CF accumulation evidenced hydrogenolysis. With Py, thiolytic reduction was revealed by CS yield and is a likely reason for different Λ value (ΔδC/ΔδCl) comparing with Fe(0) experiments at pH 7 (2.9 ± 0.5 and 6.1 ± 0.5, respectively). At pH 12, all CT experiments showed degradation to CF, again with significant diff...

The Science of the total environment, Jan 17, 2017

Field-derived anoxic microcosms were used to characterize chloroform (CF) and carbon tetrachlorid... more Field-derived anoxic microcosms were used to characterize chloroform (CF) and carbon tetrachloride (CT) natural attenuation to compare it with biostimulation scenarios in which vitamin B12 was added (B12/pollutant ratio of 0.01 and 0.1) by means of by-products, carbon and chlorine compound-specific stable-isotope analysis, and the active microbial community through 16S rRNA MiSeq high-throughput sequencing. Autoclaved slurry controls discarded abiotic degradation processes. B12 catalyzed CF and CT biodegradation without the accumulation of dichloromethane, carbon disulphide, or CF. The carbon isotopic fractionation value of CF (ƐCCF) with B12 was -14±4‰, and the value for chlorine (ƐClCF) was -2.4±0.4‰. The carbon isotopic fractionation values of CT (ƐCCT) were -16±6 with B12, and -13±2‰ without B12; and the chlorine isotopic fractionation values of CT (ƐClCT) were -6±3 and -4±2‰, respectively. Acidovorax, Ancylobacter, and Pseudomonas were the most metabolically active genera, wher...

International Biodeterioration & Biodegradation

Environmental science & technology, Jan 6, 2017

To use compound-specific isotope analysis for confidently assessing organic contaminant attenuati... more To use compound-specific isotope analysis for confidently assessing organic contaminant attenuation in the environment, isotope fractionation patterns associated with different transformation mechanisms must first be explored in laboratory experiments. To deliver this information for the common groundwater contaminant chloroform (CF), this study investigated for the first time both carbon and chlorine isotope fractionation for three different engineered reactions: oxidative C-H bond cleavage using heat-activated persulfate, transformation under alkaline conditions (pH ∼ 12) and reductive C-Cl bond cleavage by cast zerovalent iron, Fe(0). Carbon and chlorine isotope fractionation values were -8 ± 1‰ and -0.44 ± 0.06‰ for oxidation, -57 ± 5‰ and -4.4 ± 0.4‰ for alkaline hydrolysis (pH 11.84 ± 0.03), and -33 ± 11‰ and -3 ± 1‰ for dechlorination, respectively. Carbon and chlorine apparent kinetic isotope effects (AKIEs) were in general agreement with expected mechanisms (C-H bond cleava...

Science of The Total Environment, 2017

Biodegradation of dichloromethane (DCM) under reducing conditions is of major concern due to its ... more Biodegradation of dichloromethane (DCM) under reducing conditions is of major concern due to its widespread detection in contaminated groundwaters. Here, we report an anaerobic enrichment culture derived from a membrane bioreactor operating in an industrial wastewater treatment plant, capable of fermenting DCM and the brominated analogue dibromomethane (DBM). Comparative analysis of bacterial 16S rDNA-DGGE profiles from fresh liquid medium inoculated with single colonies picked from serial dilution-to-extinction agar vials showed that cultures degrading DCM contained a predominant band belonging to Dehalobacterium, however this band was absent in cultures unable to degrade DCM. Analysis of the microbial composition of the enrichment by bacterial 16S rRNA gene amplicon paired-end sequencing confirmed the presence of Dehalobacterium together with three additional phylotypes belonging to Acetobacterium, Desulfovibrio, and Wolinella, representing all four operational taxonomic units >99.9% of the retrieved sequences. The carbon isotopic fractionation (ε) determined for DCM degradation in this culture was -27±2‰. This value differs from the ε previously reported for the DCM-fermentative bacteria Dehalobacter (-15.5±1.5‰) but they are both significantly different from those reported for facultative methylotrophic organisms (ranging from -45 to -61‰). This significant difference in the ε allows differentiating between hydrolytic transformation of DCM via glutathione-dependent dehalogenases and fermentation pathway. The carbon isotopic fractionation of dichloromethane by an enriched Dehalobacterium-containing culture has significant potential to monitor biodegradation of DCM in groundwaters.

Journal of Hazardous Materials, 2015

Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess t... more Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess the effect of a zero-valent iron-permeable reactive barrier (ZVI-PRB) installation at a site contaminated with tetrachloroethene (PCE) and trichloroethene (TCE). The focus was on 1) using 13 C to evaluate natural chlorinated ethene biodegradation and the ZVI-PRB efficiency; 2) using dual element 13 C-37 Cl isotopic analysis to distinguish biotic from abiotic degradation of cis-dichloroethene (cis-DCE); and 3) using 13 C-37 Cl-2 H isotopic analysis of cis-DCE and TCE to elucidate different contaminant sources. Both biodegradation and degradation by ZVI-PRB were indicated by the metabolites that were detected and the 13 C data, with a quantitative estimate of the ZVI-PRB efficiency of less than 10% for PCE. Dual element 13 C-37 Cl isotopic plots confirmed that biodegradation was the main process at the site including the ZVI-PRB area. Based on the carbon isotope data, approximately 45% and 71% of PCE and TCE, respectively, were estimated to be removed by biodegradation. 2 H combined with 13 C and 37 Cl seems to have identified two discrete sources contributing to the contaminant plume, indicating the potential of δ 2 H to discriminate whether a compound is of industrial origin, or whether a compound is formed as a daughter product during degradation.

Environmental science & technology, Jan 25, 2015

A stable enrichment culture derived from Besòs river estuary sediments stoichiometrically dechlor... more A stable enrichment culture derived from Besòs river estuary sediments stoichiometrically dechlorinated 1,2-dichloropropane (1,2-DCP) to propene. Sequential transfers in defined anaerobic medium with the inhibitor bromoethanesulfonate produced a sediment-free culture dechlorinating 1,2-DCP in the absence of methanogenesis. Application of previously published genus-specific primers targeting 16S rRNA gene sequences revealed the presence of a Dehalogenimonas strain, and no amplification was obtained with Dehalococcoides-specific primers. The partial sequence of the 16S rRNA amplicon was 100% identical with Dehalogenimonas alkenigignens strain IP3-3. Also, dcpA, a gene described to encode a corrinoid-containing 1,2-DCP reductive dehalogenase was detected. Resistance of the dehalogenating activity to vancomycin, exclusive conversion of vicinally chlorinated alkanes, and tolerance to short-term oxygen exposure is consistent with the hypothesis that a Dehalogenimonas strain is responsible...

The Handbook of Environmental Chemistry, 2007

Isotope fractionation of fuel oxygenates has been employed as an indicator for monitoring in-situ... more Isotope fractionation of fuel oxygenates has been employed as an indicator for monitoring in-situ degradation in the field. For quantification of in-situ degradation, the Rayleigh concept can be applied. The selection of an appropriate isotope enrichment factor (ε) that is representative of the biogeochemical conditions governing the microbial 100 M. Rosell et al. degradation process in the field is crucial for quantification. Therefore, the biogeochemistry of contaminated aquifers has to be taken into account in the development of isotope strategies in assessment and monitoring operations. In addition, controlled microcosms studies are needed to determine the extent of isotope fractionation under different conditions. The simultaneous analysis of carbon and hydrogen isotope composition of fuel oxygenates in a two-dimensional isotope approach opens opportunities for analysis of the predominant degradation process in the field and can be used to select an appropriate fractionation factor. In this contribution we summarise the concept of isotope fractionation of fuel oxygenates to assess in-situ degradation with respect to analytical techniques, recent progress on isotope fractionation in laboratory studies, the concept of two-dimensional isotope analysis, and experience from field studies. Keywords MTBE • ETBE fuel oxygenates • CSIA (compound-specific stable isotope analysis) • In-situ biodegradation Abbreviations B Biodegradation extent BTEX Benzene, toluene, ethylbenzene and xylenes C Concentration of pollutant CSIA Compound-specific isotope analysis DIN Deutsches Institut

Journal of hazardous materials, Jan 18, 2014

Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental ... more 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...

... [16] measured average MTBE content in German regular (0.4%), eu-rosuper (0.4–4.2%), super pre... more ... [16] measured average MTBE content in German regular (0.4%), eu-rosuper (0.4–4.2%), super premium unleaded (9.8%), and ... being substituted by ETBE due to tax incentives for the application of biomass-derived ethanol, which is ... [24] who developed HS-SPME-GC/MS to ...

TrAC Trends in Analytical Chemistry, 2006

... P-THREE (“Removal of Persistent Polar Pollutants through improved treatment of wastewater eff... more ... P-THREE (“Removal of Persistent Polar Pollutants through improved treatment of wastewater effluents ... Figure 2. Evolution in the composition of British Petroleum (BP) gasoline in Spain ... Accidental spills and leakage from corroded tanks at gasoline stations and refineries are the ...

Journal of Hazardous Materials, 2012

Ethyl tert-butyl ether (ETBE) was detected at high concentration (300mgL(-1)) in the groundwater ... more Ethyl tert-butyl ether (ETBE) was detected at high concentration (300mgL(-1)) in the groundwater below a gas-station. No significant carbon neither hydrogen isotopic fractionation of ETBE was detected along the plume. ETBE and BTEX biodegradation capacities of the indigenous microflora Pz1-ETBE and of a culture (MC-IFP) composed of Rhodococcus wratislaviensis IFP 2016, Rhodococcus aetherivorans IFP 2017 and Aquincola tertiaricarbonis IFP 2003 showed that ETBE and BTEX degradation rates were in the same range (ETBE: 0.91 and 0.83 mg L(-1)h(-1) and BTEX: 0.64 and 0.82 mg L(-1)h(-1), respectively) but tert-butanol (TBA) accumulated transiently at a high level using Pz1-ETBE (74 mg L(-1)). An on-site pilot plant (2m(3)) filled with polluted groundwater and inoculated by MC-IFP, successfully degraded four successive additions of ETBE and gasoline. However, an insignificant ETBE isotopic fractionation was also accompanying this decrease which suggested the involvement of low fractionating-strains using EthB enzymes, but required of additional proofs. The ethB gene encoding a cytochrome P450 involved in ETBE biodegradation (present in R. aetherivorans IFP 2017) was monitored by quantitative real-time polymerase chain reaction (q-PCR) on DNA extracted from water sampled in the pilot plant which yield up to 5×10(6) copies of ethB gene per L(-1).

Chromatographia, 2002

Heacl space gas chromatography with flame-ionization detection (HS-GC-FID), ancl purge and trap g... more Heacl space gas chromatography with flame-ionization detection (HS-GC-FID), ancl purge and trap gas chromatography-mass spectrometry (P&T-GC-MS) have been used to determine methyl-tert-butyl ether (MTBE) and benzene, toluene, and the xylenes (BTEX) in groundwater. In the work discussed in this paper measures of quality, e.g. recovery (94-111%), precision (4.6-12.2%), limits of detection (0.3-5.7 I~g L 1 for HS and 0.001 I~g L 1 for PT), and robustness, for both methods were compared. In addition, for purposes of comparison, groundwater samples from areas suffering from odor problems because of fuel spillage and tank leakage were analyzed by use of both techniques. For high concentration levels there was good correlation between results from both methods. Results from P&T analysis showed that 20 of the 21 samples from the vulnerable areas contained MTBE at concentrations up to 666 I~g L 1. Levels in seven samples exceeded maximum permissible levels for odor and taste set by the USEPA (20-40 I~g L 1); for thirteen of the samples levels were bel',,veen 0.28 and 179 I~g L 1. The sensitivily of HS-GC-FID was, however, I',,vo to three orders of magnitude lower and concentrations of 6-10 I~g L 1 could not always be detected, leading to false negatives. The same behavior was observed for analysis of BTEXthe lower sensitivity of HS-GC-FID and coelution of peaks led to results of poor rehabihty, and confirmation by GC-MS was always necessary. The applicability of I',,vo analytical methods widely used for routine monitoring of VOC thus depends on the organoleptic thresholds of MTBE and BTEX in groundwater (20 I~g L 1) and the need to survey trace concentrations of persistent MTBE in vulnerable aquifers.

Water Research

Based on the previously observed intrinsic bioremediation potential of a site originally contamin... more Based on the previously observed intrinsic bioremediation potential of a site originally contaminated with perchloroethene (PCE), field-derived lactate-amended microcosms were performed to test different lactate isomers and concentrations, and find clearer isotopic and molecular parameters proving the feasibility of an in-situ enhanced reductive dechlorination (ERD) from PCE-to-ethene (ETH). According to these laboratory results, which confirmed the presence of Dehalococcoides sp. and the vcrA gene, an in-situ ERD pilot test consisting of a single injection of lactate in a monitoring well was performed and monitored for 190 days. The parameters used to follow the performance of the ERD comprised the analysis of i) hydrochemistry, including redox potential (Eh), and the concentrations of redox sensitive species, chlorinated ethenes (CEs), lactate, and acetate; ii) stable isotope composition of carbon of CEs, and sulphur and oxygen of sulphate; and iii) 16S rRNA gene sequencing from groundwater samples. Thus, it was proved that the injection of lactate promoted sulphate-reducing conditions, with the subsequent decrease in Eh, which allowed for the full reductive dechlorination of PCE to ETH in the injection well. The biodegradation of CEs was also confirmed by the enrichment in 13 C and carbon isotopic mass balances. The metagenomic results evidenced the shift in the composition of the microbial population towards the predominance of fermentative bacteria. Given the success of the in-situ pilot test, a full-scale ERD with lactate was then implemented at the site. After one year of treatment, PCE and trichloroethene were mostly depleted, whereas vinyl chloride (VC) and ETH were the predominant metabolites. Most importantly, the shift of the carbon isotopic mass balances towards more positive values confirmed the complete reductive dechlorination, including the VC-to-ETH reaction step. The combination of techniques used here provides complementary lines of evidence for the diagnosis of the intrinsic biodegradation potential of a polluted site, but also to monitor 3 the progress, identify potential difficulties, and evaluate the success of ERD at the field scale.

Science of The Total Environment

Many aquifers around the world are impacted by toxic chlorinated methanes derived from industrial... more Many aquifers around the world are impacted by toxic chlorinated methanes derived from industrial processes due to accidental spills. Frequently, these contaminants co-occur with chlorinated ethenes and/or chlorinated benzenes in groundwater, forming complex mixtures that become very difficult to remediate. In this study, a multi-method approach was used to provide lines of evidence of natural attenuation processes and potential setbacks in the implementation of bioremediation strategies in multi-contaminated aquifers. First, this study determined i) the carbon and chlorine isotopic compositions (δ 13 C, δ 37 Cl) of several commercial pure phase chlorinated compounds, and ii) the chlorine isotopic fractionation (εCl =-5.2 ± 0.6‰) and the dual C-Cl isotope correlation (Λ C/Cl = 5.9 ± 0.3) during dichloromethane (DCM) degradation by a Dehalobacteriumcontaining culture. Such data provide valuable information for practitioners to support the interpretation of stable isotope analyses derived from polluted sites. Second, the bioremediation potential of two industrial sites contaminated with a mixture of organic pollutants (mainly DCM, chloroform (CF), trichloroethene (TCE), and monochlorobenzene (MCB)) was evaluated. Hydrochemistry, dual (C-Cl) isotope analyses, laboratory microcosms, and microbiological data were used to investigate the origin, fate and biodegradation potential of chlorinated methanes. At Site 1, δ 13 C and δ 37 Cl compositions from field samples were consistent with laboratory microcosms, which showed complete degradation of CF, DCM and TCE, while MCB remained.

E3S Web of Conferences

We used C-Cl dual isotope analysis and microcosm studies for elucidating the origin and fate of t... more We used C-Cl dual isotope analysis and microcosm studies for elucidating the origin and fate of the common groundwater pollutant dichloromethane (DCM) in two different multi-contaminant field sites in Catalonia, Spain; where DCM contamination could be the result of direct solvent releases and/or chloroform (CF) transformation. Known commercial solvents isotopic compositions as well as characteristic C-Cl dual isotope slopes from our anaerobic enrichment culture containing Dehalobacterium sp., capable of fermenting DCM, and other bacteria from the literature were used for field data interpretation.

Environmental Pollution

The bioremediation potential of an aquifer contaminated with tetrachloroethene (PCE) was assessed... more The bioremediation potential of an aquifer contaminated with tetrachloroethene (PCE) was assessed by combining hydrogeochemical data of the site, microcosm studies, metabolites concentrations, compound specific-stable carbon isotope analysis and the identification of selected reductive dechlorination biomarker genes. The characterization of the site through 10 monitoring wells evidenced that leaked PCE was transformed to TCE and cis-DCE via hydrogenolysis. Carbon isotopic mass balance of chlorinated ethenes pointed to two distinct sources of contamination and discarded relevant alternate degradation pathways in the aquifer. Application of specific-genus primers targeting Dehalococcoides mccartyi species and the vinyl chloride-to-ethene reductive dehalogenase vcrA indicated the presence of autochthonous bacteria capable of the complete dechlorination of PCE. The observed cis-DCE stall was consistent with the aquifer geochemistry (positive redox potentials; presence of dissolved oxygen, nitrate, and sulphate; absence of ferrous iron), which was thermodynamically favourable to dechlorinate highly chlorinated ethenes but required lower redox potentials to evolve beyond cis-DCE to the innocuous end product ethene. Accordingly, the addition of lactate or a mixture of ethanol plus methanol as electron donor sources in parallel field-derived anoxic microcosms accelerated dechlorination of PCE and passed cis-DCE up to ethene, unlike the controls (without amendments, representative of field natural attenuation). Lactate fermentation produced acetate at near-stoichiometric amounts. The array of techniques used in this study provided complementary lines of evidence to suggest that enhanced anaerobic bioremediation using lactate as electron donor source is a feasible strategy to successfully decontaminate this site.

The Science of the total environment, Jan 16, 2018

The effects of contaminant sources removal in 2005 (i.e. barrels, tank, pit and wastewater pipe s... more The effects of contaminant sources removal in 2005 (i.e. barrels, tank, pit and wastewater pipe sources) on carbon tetrachloride (CT) and chloroform (CF) concentration in groundwater were assessed at several areas of a fractured multi-contaminant aquifer (Òdena, Spain) over a long-term period (2010-2014). Changes in redox conditions, in these chlorinated methanes (CMs) concentration and in their carbon isotopic compositions (δC) were monitored in multilevel wells. δC values from these wells were compared to those obtained from sources (barrels, tank and pit before their removal, 2002-2005) and to commercial solvents values in literature. Additionally, CMs natural attenuation processes were identified by C-Cl isotope slopes (Λ). Analyses revealed the downstream migration of the pollutant focus and an efficient removal of DNAPLs in the pit source's influence area. However, the removal of the contaminated soil from former tank and wastewater pipe was incomplete as leaching from uns...

The Science of the total environment, Jan 6, 2018

Chlorinated ethanes are frequent groundwater contaminants but compound specific isotope analysis ... more Chlorinated ethanes are frequent groundwater contaminants but compound specific isotope analysis (CSIA) has been scarcely applied to investigate their degradation pathways. In this study, dual carbon and chlorine isotope fractionation was used to investigate for the first time the anoxic biodegradation of 1,1,2-trichloroethane (1,1,2-TCA) using a Dehalogenimonas-containing culture. The isotopic fractionation values obtained for the biodegradation of 1,1,2-TCA were ɛ = -6.9 ± 0.4‰ and ɛ = -2.7 ± 0.3‰. The detection of vinyl chloride (VC) as unique byproduct and a closed carbon isotopic mass balance corroborated that dichloroelimination was the degradation pathway used by this strain. Combining the values of δC and δCl resulted in a dual element C-Cl isotope slope of Λ = 2.5 ± 0.2‰. Investigation of the apparent kinetic isotope effects (AKIEs) expected for cleavage of a CCl bond showed an important masking of the intrinsic isotope fractionation. Theoretical calculation of Λ suggested ...

Chemosphere, Jan 7, 2018

A dual element CCl isotopic study was performed for assessing chlorinated methanes (CMs) abiotic ... more A dual element CCl isotopic study was performed for assessing chlorinated methanes (CMs) abiotic transformation reactions mediated by iron minerals and Fe(0) to further distinguish them in natural attenuation monitoring or when applying remediation strategies in polluted sites. Isotope fractionation was investigated during carbon tetrachloride (CT) and chloroform (CF) degradation in anoxic batch experiments with Fe(0), with FeCl(aq), and with Fe-bearing minerals (magnetite, Mag and pyrite, Py) amended with FeCl(aq), at two different pH values (7 and 12) representative of field and remediation conditions. At pH 7, only CT batches with Fe(0) and Py underwent degradation and CF accumulation evidenced hydrogenolysis. With Py, thiolytic reduction was revealed by CS yield and is a likely reason for different Λ value (ΔδC/ΔδCl) comparing with Fe(0) experiments at pH 7 (2.9 ± 0.5 and 6.1 ± 0.5, respectively). At pH 12, all CT experiments showed degradation to CF, again with significant diff...

The Science of the total environment, Jan 17, 2017

Field-derived anoxic microcosms were used to characterize chloroform (CF) and carbon tetrachlorid... more Field-derived anoxic microcosms were used to characterize chloroform (CF) and carbon tetrachloride (CT) natural attenuation to compare it with biostimulation scenarios in which vitamin B12 was added (B12/pollutant ratio of 0.01 and 0.1) by means of by-products, carbon and chlorine compound-specific stable-isotope analysis, and the active microbial community through 16S rRNA MiSeq high-throughput sequencing. Autoclaved slurry controls discarded abiotic degradation processes. B12 catalyzed CF and CT biodegradation without the accumulation of dichloromethane, carbon disulphide, or CF. The carbon isotopic fractionation value of CF (ƐCCF) with B12 was -14±4‰, and the value for chlorine (ƐClCF) was -2.4±0.4‰. The carbon isotopic fractionation values of CT (ƐCCT) were -16±6 with B12, and -13±2‰ without B12; and the chlorine isotopic fractionation values of CT (ƐClCT) were -6±3 and -4±2‰, respectively. Acidovorax, Ancylobacter, and Pseudomonas were the most metabolically active genera, wher...

International Biodeterioration & Biodegradation

Environmental science & technology, Jan 6, 2017

To use compound-specific isotope analysis for confidently assessing organic contaminant attenuati... more To use compound-specific isotope analysis for confidently assessing organic contaminant attenuation in the environment, isotope fractionation patterns associated with different transformation mechanisms must first be explored in laboratory experiments. To deliver this information for the common groundwater contaminant chloroform (CF), this study investigated for the first time both carbon and chlorine isotope fractionation for three different engineered reactions: oxidative C-H bond cleavage using heat-activated persulfate, transformation under alkaline conditions (pH ∼ 12) and reductive C-Cl bond cleavage by cast zerovalent iron, Fe(0). Carbon and chlorine isotope fractionation values were -8 ± 1‰ and -0.44 ± 0.06‰ for oxidation, -57 ± 5‰ and -4.4 ± 0.4‰ for alkaline hydrolysis (pH 11.84 ± 0.03), and -33 ± 11‰ and -3 ± 1‰ for dechlorination, respectively. Carbon and chlorine apparent kinetic isotope effects (AKIEs) were in general agreement with expected mechanisms (C-H bond cleava...

Science of The Total Environment, 2017

Biodegradation of dichloromethane (DCM) under reducing conditions is of major concern due to its ... more Biodegradation of dichloromethane (DCM) under reducing conditions is of major concern due to its widespread detection in contaminated groundwaters. Here, we report an anaerobic enrichment culture derived from a membrane bioreactor operating in an industrial wastewater treatment plant, capable of fermenting DCM and the brominated analogue dibromomethane (DBM). Comparative analysis of bacterial 16S rDNA-DGGE profiles from fresh liquid medium inoculated with single colonies picked from serial dilution-to-extinction agar vials showed that cultures degrading DCM contained a predominant band belonging to Dehalobacterium, however this band was absent in cultures unable to degrade DCM. Analysis of the microbial composition of the enrichment by bacterial 16S rRNA gene amplicon paired-end sequencing confirmed the presence of Dehalobacterium together with three additional phylotypes belonging to Acetobacterium, Desulfovibrio, and Wolinella, representing all four operational taxonomic units >99.9% of the retrieved sequences. The carbon isotopic fractionation (ε) determined for DCM degradation in this culture was -27±2‰. This value differs from the ε previously reported for the DCM-fermentative bacteria Dehalobacter (-15.5±1.5‰) but they are both significantly different from those reported for facultative methylotrophic organisms (ranging from -45 to -61‰). This significant difference in the ε allows differentiating between hydrolytic transformation of DCM via glutathione-dependent dehalogenases and fermentation pathway. The carbon isotopic fractionation of dichloromethane by an enriched Dehalobacterium-containing culture has significant potential to monitor biodegradation of DCM in groundwaters.

Journal of Hazardous Materials, 2015

Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess t... more Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess the effect of a zero-valent iron-permeable reactive barrier (ZVI-PRB) installation at a site contaminated with tetrachloroethene (PCE) and trichloroethene (TCE). The focus was on 1) using 13 C to evaluate natural chlorinated ethene biodegradation and the ZVI-PRB efficiency; 2) using dual element 13 C-37 Cl isotopic analysis to distinguish biotic from abiotic degradation of cis-dichloroethene (cis-DCE); and 3) using 13 C-37 Cl-2 H isotopic analysis of cis-DCE and TCE to elucidate different contaminant sources. Both biodegradation and degradation by ZVI-PRB were indicated by the metabolites that were detected and the 13 C data, with a quantitative estimate of the ZVI-PRB efficiency of less than 10% for PCE. Dual element 13 C-37 Cl isotopic plots confirmed that biodegradation was the main process at the site including the ZVI-PRB area. Based on the carbon isotope data, approximately 45% and 71% of PCE and TCE, respectively, were estimated to be removed by biodegradation. 2 H combined with 13 C and 37 Cl seems to have identified two discrete sources contributing to the contaminant plume, indicating the potential of δ 2 H to discriminate whether a compound is of industrial origin, or whether a compound is formed as a daughter product during degradation.

Environmental science & technology, Jan 25, 2015

A stable enrichment culture derived from Besòs river estuary sediments stoichiometrically dechlor... more A stable enrichment culture derived from Besòs river estuary sediments stoichiometrically dechlorinated 1,2-dichloropropane (1,2-DCP) to propene. Sequential transfers in defined anaerobic medium with the inhibitor bromoethanesulfonate produced a sediment-free culture dechlorinating 1,2-DCP in the absence of methanogenesis. Application of previously published genus-specific primers targeting 16S rRNA gene sequences revealed the presence of a Dehalogenimonas strain, and no amplification was obtained with Dehalococcoides-specific primers. The partial sequence of the 16S rRNA amplicon was 100% identical with Dehalogenimonas alkenigignens strain IP3-3. Also, dcpA, a gene described to encode a corrinoid-containing 1,2-DCP reductive dehalogenase was detected. Resistance of the dehalogenating activity to vancomycin, exclusive conversion of vicinally chlorinated alkanes, and tolerance to short-term oxygen exposure is consistent with the hypothesis that a Dehalogenimonas strain is responsible...

The Handbook of Environmental Chemistry, 2007

Isotope fractionation of fuel oxygenates has been employed as an indicator for monitoring in-situ... more Isotope fractionation of fuel oxygenates has been employed as an indicator for monitoring in-situ degradation in the field. For quantification of in-situ degradation, the Rayleigh concept can be applied. The selection of an appropriate isotope enrichment factor (ε) that is representative of the biogeochemical conditions governing the microbial 100 M. Rosell et al. degradation process in the field is crucial for quantification. Therefore, the biogeochemistry of contaminated aquifers has to be taken into account in the development of isotope strategies in assessment and monitoring operations. In addition, controlled microcosms studies are needed to determine the extent of isotope fractionation under different conditions. The simultaneous analysis of carbon and hydrogen isotope composition of fuel oxygenates in a two-dimensional isotope approach opens opportunities for analysis of the predominant degradation process in the field and can be used to select an appropriate fractionation factor. In this contribution we summarise the concept of isotope fractionation of fuel oxygenates to assess in-situ degradation with respect to analytical techniques, recent progress on isotope fractionation in laboratory studies, the concept of two-dimensional isotope analysis, and experience from field studies. Keywords MTBE • ETBE fuel oxygenates • CSIA (compound-specific stable isotope analysis) • In-situ biodegradation Abbreviations B Biodegradation extent BTEX Benzene, toluene, ethylbenzene and xylenes C Concentration of pollutant CSIA Compound-specific isotope analysis DIN Deutsches Institut

Journal of hazardous materials, Jan 18, 2014

Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental ... more 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...

... [16] measured average MTBE content in German regular (0.4%), eu-rosuper (0.4–4.2%), super pre... more ... [16] measured average MTBE content in German regular (0.4%), eu-rosuper (0.4–4.2%), super premium unleaded (9.8%), and ... being substituted by ETBE due to tax incentives for the application of biomass-derived ethanol, which is ... [24] who developed HS-SPME-GC/MS to ...

TrAC Trends in Analytical Chemistry, 2006

... P-THREE (“Removal of Persistent Polar Pollutants through improved treatment of wastewater eff... more ... P-THREE (“Removal of Persistent Polar Pollutants through improved treatment of wastewater effluents ... Figure 2. Evolution in the composition of British Petroleum (BP) gasoline in Spain ... Accidental spills and leakage from corroded tanks at gasoline stations and refineries are the ...

Journal of Hazardous Materials, 2012

Ethyl tert-butyl ether (ETBE) was detected at high concentration (300mgL(-1)) in the groundwater ... more Ethyl tert-butyl ether (ETBE) was detected at high concentration (300mgL(-1)) in the groundwater below a gas-station. No significant carbon neither hydrogen isotopic fractionation of ETBE was detected along the plume. ETBE and BTEX biodegradation capacities of the indigenous microflora Pz1-ETBE and of a culture (MC-IFP) composed of Rhodococcus wratislaviensis IFP 2016, Rhodococcus aetherivorans IFP 2017 and Aquincola tertiaricarbonis IFP 2003 showed that ETBE and BTEX degradation rates were in the same range (ETBE: 0.91 and 0.83 mg L(-1)h(-1) and BTEX: 0.64 and 0.82 mg L(-1)h(-1), respectively) but tert-butanol (TBA) accumulated transiently at a high level using Pz1-ETBE (74 mg L(-1)). An on-site pilot plant (2m(3)) filled with polluted groundwater and inoculated by MC-IFP, successfully degraded four successive additions of ETBE and gasoline. However, an insignificant ETBE isotopic fractionation was also accompanying this decrease which suggested the involvement of low fractionating-strains using EthB enzymes, but required of additional proofs. The ethB gene encoding a cytochrome P450 involved in ETBE biodegradation (present in R. aetherivorans IFP 2017) was monitored by quantitative real-time polymerase chain reaction (q-PCR) on DNA extracted from water sampled in the pilot plant which yield up to 5×10(6) copies of ethB gene per L(-1).