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Gil-Villalba S, Palau J, Soder-Walz JM, Vallecillo MA, Corregidor J, Tirado A, Shouakar-Stash O, Guivernau M, Viñas M, Soler A, Rosell M. Use of isotopic (C, Cl) and molecular biology tools to assess biodegradation in a source area of chlorinated ethenes after biostimulation with Emulsified Vegetable Oil (EVO). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175351. [PMID: 39151619 DOI: 10.1016/j.scitotenv.2024.175351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 08/04/2024] [Accepted: 08/05/2024] [Indexed: 08/19/2024]
Abstract
Enhanced In Situ Bioremediation (EISB) using Emulsified Vegetable Oil (EVO) as a long-term electron donor has gained prominence for the treatment of groundwater contaminated with chlorinated ethenes (CEs). This study explores the potential of isotopic and molecular biology tools (MBT) to investigate the CEs (PCE, TCE and cis-DCE) bioremediation using EVO in a contaminated site. A multiple approach using C and Cl-CSIA, quantification of Dehalococcoides (Dhc) and specific reductive dechlorination (RD) gene population, and hydrochemical data in microcosm experiments and field samples was applied. Despite the high partitioning of CEs into the EVO phase, the carbon isotopic values of the remaining CEs fraction in the aqueous phase did not exhibit significant changes caused by phase partitioning in laboratory experiments. Both microcosm experiments and field data revealed a rapid RD of PCE and TCE, resulting in the transient accumulation of cis-DCE, which was slowly degraded to vinyl chloride (VC). These results agreed with the presence of Dhc populations and a shift to stronger reducing conditions in the field: i) RD functional genes (tceA, vcrA and bvcA) exhibited a trend to higher values and ii) a substantial increase in Dhc populations (up to 30% of the total bacterial populations) was observed over time. The dual-element isotope slope ΛC-Cl for RD of cis-DCE obtained from field data (ΛC - Cl = 5 ± 3) was similar to the one determined from the microcosm experiments under controlled anoxic conditions (ΛC - Cl = 4.9 ± 0.8). However, ΛC-Cl values differ from those reported so far for laboratory studies with Dhc strains and mixed cultures containing Dhc, i.e., between 8.3 and 17.8. This observation underscores the potential variety of reductive dehalogenases involved during cis-DCE RD and the importance of determining site-specific Λ and ɛ values in order to improve the identification and quantification of transformation processes in the field.
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Affiliation(s)
- Sergio Gil-Villalba
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí Franquès s/n, 08028 Barcelona, Spain.
| | - Jordi Palau
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí Franquès s/n, 08028 Barcelona, Spain
| | - Jesica M Soder-Walz
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Miguel A Vallecillo
- Environmental Resources Management Iberia SAU, Rambla de Catalunya 33, 08007 Barcelona, Spain
| | - Jordi Corregidor
- Environmental Resources Management Iberia SAU, Rambla de Catalunya 33, 08007 Barcelona, Spain
| | - Andrea Tirado
- Environmental Resources Management Iberia SAU, Rambla de Catalunya 33, 08007 Barcelona, Spain
| | | | - Miriam Guivernau
- Sustainability in Biosystems Programme, Institute of Agrifood Research and Technology (IRTA), Torre Marimon, Caldes de Montbui, Barcelona, Spain
| | - Marc Viñas
- Sustainability in Biosystems Programme, Institute of Agrifood Research and Technology (IRTA), Torre Marimon, Caldes de Montbui, Barcelona, Spain
| | - Albert Soler
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí Franquès s/n, 08028 Barcelona, Spain
| | - Monica Rosell
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí Franquès s/n, 08028 Barcelona, Spain
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Vinyes-Nadal M, Kümmel S, Espín Y, Gómez-Alday JJ, Gehre M, Otero N, Torrentó C. Dual C and Cl compound-specific isotope analysis and metagenomic insights into the degradation of the pesticide methoxychlor. JOURNAL OF HAZARDOUS MATERIALS 2024; 480:135929. [PMID: 39321483 DOI: 10.1016/j.jhazmat.2024.135929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 09/07/2024] [Accepted: 09/19/2024] [Indexed: 09/27/2024]
Abstract
This study investigates the use of multi-element compound-specific isotope analysis (ME-CSIA) to monitor degradation processes of methoxychlor, a persistent organochlorine insecticide. Laboratory experiments examined the kinetics, release of transformation products, and carbon and chlorine isotope effects during methoxychlor degradation through alkaline hydrolysis, oxidation with alkaline-activated persulfate, and biotic reductive dechlorination. Results showed that hydrolysis and oxidation did not cause significant carbon and chlorine isotope fractionation, indicating that C-H rather than C-Cl bond cleavage was the rate-determining step. Conversely, biotic reductive dechlorination by a field-derived microcosm under strictly anoxic conditions displayed significant carbon (εC = -0.9 ± 0.3 ‰) and chlorine (εCl = -1.9 ± 1.0 ‰) isotope fractionation. Its corresponding calculated dual isotope slope (ΛC/Cl = 0.4 ± 0.1) and apparent kinetic isotope effects (AKIEC = 1.014 ± 0.005 and AKIECl = 1.006 ± 0.003) indicate a C-Cl bond cleavage as the rate-determining step, highlighting the difference with respect to the other studied degradation mechanisms. Changes in the microbial community diversity revealed that families such as Dojkabacteria, Anaerolineaceae, Dysgonomonadaceae, Bacteroidetes vadinHA17, Pseudomonadaceae, and Spirochaetaceae, may be potential agents of methoxychlor reductive dechlorination under anoxic conditions. This study advances the understanding of degradation mechanisms of methoxychlor and improves the ability to track its transformation in contaminated environments, including for the first time an isotopic perspective.
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Affiliation(s)
- Martí Vinyes-Nadal
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí i Franquès s/n, 08028 Barcelona, Spain.
| | - Steffen Kümmel
- Department of Technical Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Yolanda Espín
- Group of Hydrogeology, Biotechnology and Natural Resources Laboratory, Institute for Regional Development (IDR), University of Castilla-La Mancha (UCLM), 02071 Albacete, Spain
| | - Juan José Gómez-Alday
- Group of Hydrogeology, Biotechnology and Natural Resources Laboratory, Institute for Regional Development (IDR), University of Castilla-La Mancha (UCLM), 02071 Albacete, Spain
| | - Matthias Gehre
- Department of Technical Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Neus Otero
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí i Franquès s/n, 08028 Barcelona, Spain; Serra Húnter Fellowship, Generalitat de Catalunya, Spain
| | - Clara Torrentó
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí i Franquès s/n, 08028 Barcelona, Spain; Serra Húnter Fellowship, Generalitat de Catalunya, Spain
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3
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Pinel-Cabello M, Wasmund K, Soder-Walz JM, Vega M, Rosell M, Marco-Urrea E. Divergent dual C-H isotopic fractionation pattern during anaerobic biodegradation of toluene within Aromatoleum species under nitrate-reducing conditions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 361:124823. [PMID: 39197649 DOI: 10.1016/j.envpol.2024.124823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 07/22/2024] [Accepted: 08/25/2024] [Indexed: 09/01/2024]
Abstract
Toluene is a pollutant frequently detected in contaminated groundwater, mostly due to leakage from underground gasoline storage tanks and pipeline ruptures. Multi-element compound-specific isotope analysis provides a framework to understand transformation processes and design efficient remediation strategies. In this study, we enriched an anaerobic bacterial culture derived from a BTEX-contaminated aquifer that couples toluene and phenol oxidation with nitrate reduction and the concomitant production of carbon dioxide and biomass. The 16S rRNA gene amplicon data indicated that the toluene-degrading consortium was dominated by an Aromatoleum population (87 ± 2 % relative abundance), and metagenome sequencing confirmed that the genome of this Aromatoleum sp. encoded glycyl-radical enzyme benzylsuccinate synthase (BssABC) and phenylphospate synthase (PpsA1BC) homologous genes involved in the first step of toluene and phenol transformation, respectively. Carbon and hydrogen isotopic fractionation were εbulk, C = - 3.5 ± 0.6 ‰ and εrp, H = - 85 ± 11 ‰, respectively, leading to a dual C-H isotope slope of ΛH/C = 26 ± 2. This value fits with a previously reported value for a consortium dominated by an Azoarcus species (ΛH/C = 19 ± 5) but differs from that reported for Aromatoleum aromaticum (ΛH/C = 14 ± 1), both of which grow with toluene under nitrate-reducing conditions. Overall, this suggests the existence of different BssABC enzymes with different mechanistic motifs even within the same Aromatoleum genus.
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Affiliation(s)
- Maria Pinel-Cabello
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Kenneth Wasmund
- School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Jesica M Soder-Walz
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Maria Vega
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Mònica Rosell
- Grup MAiMA, Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028, Barcelona, Spain
| | - Ernest Marco-Urrea
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain.
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Phillips E, Picott K, Kümmel S, Bulka O, Edwards E, Wang P, Gehre M, Nijenhuis I, Lollar BS. Vitamin B 12 as a source of variability in isotope effects for chloroform biotransformation by Dehalobacter. Microbiologyopen 2024; 13:e1433. [PMID: 39190020 PMCID: PMC11348799 DOI: 10.1002/mbo3.1433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/03/2024] [Accepted: 08/01/2024] [Indexed: 08/28/2024] Open
Abstract
Carbon and chlorine isotope effects for biotransformation of chloroform by different microbes show significant variability. Reductive dehalogenases (RDase) enzymes contain different cobamides, affecting substrate preferences, growth yields, and dechlorination rates and extent. We investigate the role of cobamide type on carbon and chlorine isotopic signals observed during reductive dechlorination of chloroform by the RDase CfrA. Microcosm experiments with two subcultures of a Dehalobacter-containing culture expressing CfrA-one with exogenous cobamide (Vitamin B12, B12+) and one without (to drive native cobamide production)-resulted in a markedly smaller carbon isotope enrichment factor (εC, bulk) for B12- (-22.1 ± 1.9‰) compared to B12+ (-26.8 ± 3.2‰). Both cultures exhibited significant chlorine isotope fractionation, and although a lower εCl, bulk was observed for B12- (-6.17 ± 0.72‰) compared to B12+ (-6.86 ± 0.77‰) cultures, these values are not statistically different. Importantly, dual-isotope plots produced identical slopes of ΛCl/C (ΛCl/C, B12+ = 3.41 ± 0.15, ΛCl/C, B12- = 3.39 ± 0.15), suggesting the same reaction mechanism is involved in both experiments, independent of the lower cobamide bases. A nonisotopically fractionating masking effect may explain the smaller fractionations observed for the B12- containing culture.
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Affiliation(s)
- Elizabeth Phillips
- Department of Earth SciencesUniversity of TorontoTorontoOntarioCanada
- Present address:
Inorganic Chemistry LaboratoryUniversity of OxfordOxfordUK
| | - Katherine Picott
- Department of Chemical Engineering and Applied ChemistryUniversity of TorontoTorontoOntarioCanada
| | - Steffen Kümmel
- Department of Technical BiogeochemistryHelmholtz Centre for Environmental Research—UFZLeipzigGermany
| | - Olivia Bulka
- Department of Chemical Engineering and Applied ChemistryUniversity of TorontoTorontoOntarioCanada
| | - Elizabeth Edwards
- Department of Chemical Engineering and Applied ChemistryUniversity of TorontoTorontoOntarioCanada
| | - Po‐Hsiang Wang
- Department of Chemical Engineering and Applied ChemistryUniversity of TorontoTorontoOntarioCanada
- Present address:
Graduate Institute of Environmental EngineeringNational Central UniversityTaoyuan CityTaiwan
| | - Matthias Gehre
- Department of Technical BiogeochemistryHelmholtz Centre for Environmental Research—UFZLeipzigGermany
| | - Ivonne Nijenhuis
- Department of Technical BiogeochemistryHelmholtz Centre for Environmental Research—UFZLeipzigGermany
| | - Barbara S. Lollar
- Department of Earth SciencesUniversity of TorontoTorontoOntarioCanada
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5
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Trueba-Santiso A, Torrentó C, Soder-Walz JM, Fernández-Verdejo D, Rosell M, Marco-Urrea E. Dual C-Cl isotope fractionation offers potential to assess biodegradation of 1,2-dichloropropane and 1,2,3-trichloropropane by Dehalogenimonas cultures. CHEMOSPHERE 2024; 358:142170. [PMID: 38679177 DOI: 10.1016/j.chemosphere.2024.142170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 03/25/2024] [Accepted: 04/26/2024] [Indexed: 05/01/2024]
Abstract
1,2-dichloropropane (1,2-DCP) and 1,2,3-trichloropropane (1,2,3-TCP) are hazardous chemicals frequently detected in groundwater near agricultural zones due to their historical use in chlorinated fumigant formulations. In this study, we show that the organohalide-respiring bacterium Dehalogenimonas alkenigignens strain BRE15 M can grow during the dihaloelimination of 1,2-DCP and 1,2,3-TCP to propene and allyl chloride, respectively. Our work also provides the first application of dual isotope approach to investigate the anaerobic reductive dechlorination of 1,2-DCP and 1,2,3-TCP. Stable carbon and chlorine isotope fractionation values for 1,2-DCP (ƐC = -13.6 ± 1.4 ‰ and ƐCl = -27.4 ± 5.2 ‰) and 1,2,3-TCP (ƐC = -3.8 ± 0.6 ‰ and ƐCl = -0.8 ± 0.5 ‰) were obtained resulting in distinct dual isotope slopes (Λ12DCP = 0.5 ± 0.1, Λ123TCP = 4 ± 2). However direct comparison of ΛC-Cl among different substrates is not possible and investigation of the C and Cl apparent kinetic isotope effects lead to the hypothesis that concerted dichloroelimination mechanism is more likely for both compounds. In fact, whole cell activity assays using cells suspensions of the Dehalogenimonas-containing culture grown with 1,2-DCP and methyl viologen as electron donor suggest that the same set of reductive dehalogenases was involved in the transformation of 1,2-DCP and 1,2,3-TCP. This study opens the door to the application of isotope techniques for evaluating biodegradation of 1,2-DCP and 1,2,3-TCP, which often co-occur in groundwaters near agricultural fields.
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Affiliation(s)
- Alba Trueba-Santiso
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Clara Torrentó
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028, Barcelona, Spain
| | - Jesica M Soder-Walz
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - David Fernández-Verdejo
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Mònica Rosell
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028, Barcelona, Spain
| | - Ernest Marco-Urrea
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain.
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Wang C, Fuller ME, Murillo-Gelvez J, Rezes RT, Hatzinger PB, Chiu PC, Heraty LJ, Sturchio NC. Carbon and Nitrogen Isotope Fractionations During Biotic and Abiotic Transformations of 2,4-Dinitroanisole (DNAN). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:5996-6006. [PMID: 38504451 DOI: 10.1021/acs.est.3c10788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
2,4-Dinitroanisole (DNAN) is a main constituent in various new insensitive munition formulations. Although DNAN is susceptible to biotic and abiotic transformations, in many environmental instances, transformation mechanisms are difficult to resolve, distinguish, or apportion on the basis solely of analysis of concentrations. We used compound-specific isotope analysis (CSIA) to investigate the characteristic isotope fractionations of the biotic (by three microbial consortia and three pure cultures) and abiotic (by 9,10-anthrahydroquinone-2-sulfonic acid [AHQS]) transformations of DNAN. The correlations of isotope enrichment factors (ΛN/C) for biotic transformations had a range of values from 4.93 ± 0.53 to 12.19 ± 1.23, which is entirely distinct from ΛN/C values reported previously for alkaline hydrolysis, enzymatic hydrolysis, reduction by Fe2+-bearing minerals and iron-oxide-bound Fe2+, and UV-driven phototransformations. The ΛN/C value associated with the abiotic reduction by AHQS was 38.76 ± 2.23, within the range of previously reported values for DNAN reduction by Fe2+-bearing minerals and iron-oxide-bound Fe2+, albeit the mean ΛN/C was lower. These results enhance the database of isotope effects accompanying DNAN transformations under environmentally relevant conditions, allowing better evaluation of the extents of biotic and abiotic transformations of DNAN that occur in soils, groundwaters, surface waters, and the marine environment.
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Affiliation(s)
- Chunlei Wang
- Department of Earth Sciences, University of Delaware, Newark, Delaware 19716, United States
| | - Mark E Fuller
- Biotechnology Development & Applications Group, APTIM, Lawrenceville, New Jersey 08648, United States
| | - Jimmy Murillo-Gelvez
- Department of Civil & Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Rachael T Rezes
- Biotechnology Development & Applications Group, APTIM, Lawrenceville, New Jersey 08648, United States
| | - Paul B Hatzinger
- Biotechnology Development & Applications Group, APTIM, Lawrenceville, New Jersey 08648, United States
| | - Pei C Chiu
- Department of Civil & Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Linnea J Heraty
- Department of Earth Sciences, University of Delaware, Newark, Delaware 19716, United States
| | - Neil C Sturchio
- Department of Earth Sciences, University of Delaware, Newark, Delaware 19716, United States
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7
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Kuznetsova OV. Current trends and challenges in the analysis of marine environmental contaminants by isotope ratio mass spectrometry. Anal Bioanal Chem 2024; 416:71-85. [PMID: 37979060 DOI: 10.1007/s00216-023-05029-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 10/26/2023] [Accepted: 10/30/2023] [Indexed: 11/19/2023]
Abstract
An increasing number of organic and inorganic pollutants are being detected in the marine environment, posing a severe threat to the ecosystem and human health, even in trace concentrations. Isotope ratio mass spectrometry (IRMS) is one of the critical methods for determining the origin and fate of environmental pollutants and characterising their transformation processes. It has been used for a relatively long time for ecological monitoring of some well-studied industrial hydrocarbons at contaminated sites. However, the method still faces many analytical challenges. This review provides a comprehensive overview of recent technical advances concerning IRMS analysis of various contaminants and discusses typical pitfalls encountered in marine environment analysis. Particular attention is given to the study of sampling techniques and sample preparation for examination, often the keys to successful research given the complexity of marine matrices and the diverse and numerous nature of contaminants. Prospects for developing IRMS to monitor pollution sources and pollutant transformation in the marine environment are outlined.
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Affiliation(s)
- Olga V Kuznetsova
- Vernadsky Institute of Geochemistry and Analytical Chemistry, Kosygin St. 19, 119991, Moscow, Russian Federation.
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8
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Ouyang WY, Kümmel S, Adrian L, Zhu YG, Richnow HH. Carbon and hydrogen stable isotope fractionation of sulfamethoxazole during anaerobic transformation catalyzed by Desulfovibrio vulgaris Hildenborough. CHEMOSPHERE 2023; 311:136923. [PMID: 36349587 DOI: 10.1016/j.chemosphere.2022.136923] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 10/11/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
The fate of antibiotics in aquatic environments is of high concern and approaches are needed to assess the transformation of antibiotics in wastewater treatment plants. Here we used the model organism Desulfovibrio vulgaris Hildenborough to analyze compound specific isotope fractionation associated with anaerobic transformation of the antibiotic sulfamethoxazole (SMX). The results show that the rearrangement of the isoxazole ring in SMX is leading to significant carbon and hydrogen isotopic fractionation (εC = -5.8 ± 0.7‰, εH = -34 ± 9‰) during anaerobic transformation. The observed carbon isotopic fractionation is significantly higher than the values reported for aerobic degradation (εC = -0.6 ± 0.1‰) or abiotic reactions (εC = -0.8 to -4.8‰ for photolysis, εC = -0.8 to -2.2‰ for advanced oxidation). This indicates that carbon isotope fractionation can be used as a parameter to differentiate reaction mechanisms of SMX transformation. The corresponding apparent kinetic isotope effect (AKIEC) for anaerobic transformation of SMX was 1.029 ± 0.003, suggesting that the mechanism for anaerobic transformation is distinct from the mechanism reported for microbial aerobic degradation (AKIEC = 1.006 ± 0.001). In addition, dual-element (C-H) isotope analysis of SMX was performed in the present study, which was achieved by utilizing gas chromatography (GC) as the separation method instead of routine liquid chromatography. This dual-element isotope analysis resulted in a Λ value of 4.5 ± 2.2. Overall, compound specific isotope analysis can be a feasible tool to monitor the mitigation of SMX in wastewater treatment plants.
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Affiliation(s)
- Wei-Ying Ouyang
- Helmholtz Centre for Environmental Research - UFZ, Isotope Biogeochemistry, Leipzig, Germany; Chair of Geobiotechnology, Technische Universität Berlin, Berlin, Germany
| | - Steffen Kümmel
- Helmholtz Centre for Environmental Research - UFZ, Isotope Biogeochemistry, Leipzig, Germany
| | - Lorenz Adrian
- Chair of Geobiotechnology, Technische Universität Berlin, Berlin, Germany; Helmholtz Centre for Environmental Research - UFZ, Environmental Biotechnology, Leipzig, Germany
| | - Yong-Guan Zhu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Hans H Richnow
- Helmholtz Centre for Environmental Research - UFZ, Isotope Biogeochemistry, Leipzig, Germany; Isodetect GmbH, Leipzig, Germany.
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9
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Blessing M, Baran N. A review on environmental isotope analysis of aquatic micropollutants: Recent advances, pitfalls and perspectives. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Liu J, Wei L, Zhang D, Tang L, Liu Y, Jing L, Liu J, Yang S. The effects of inorganic anions on degradation kinetics and isotope fractionation during the transformation of tris(2-chloroethyl) phosphate (TCEP) by UV/persulfate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157462. [PMID: 35868383 DOI: 10.1016/j.scitotenv.2022.157462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Tris(2-chloroethyl) phosphate (TCEP), as a typical chlorinated flame retardant, is attracting more attention as a carcinogen. Although persulfate-based oxidation exhibits good performance in removing refractory organic pollutants, the kinetics of persulfate-based remediation are affected by inorganic anions, which causes inaccurate remediation efficiency. This study combines steady-state radical concentration modelling with isotope fractionation to investigate the effects of inorganic anions on TCEP degradation by UV/persulfate (UV/PS). In the absence of anions during UV/PS system, the observed degradation rate was (9.7 ± 0.1) × 10-5 s-1, which was approximately 93 % attributed to sulfate radical (SO4-•) oxidation based on radical modelling. Carbon isotope fractionation, coupled with the identification of transformation products by mass spectrometry, suggests a carbon bond split during TCEP degradation with a carbon isotopic fractionation value (ε) of -1.6 ± 0.2 ‰ (± 95 % confidence intervals). With respect to co-existing anions in UV/PS system, the addition of chloride (Cl-) had a negligible effect on degradation rates, while the addition of hydrogencarbonate (HCO3-) caused them to decrease, and the addition of hydrogenphosphate (HPO42-) caused them to increase. Radical modelling suggested that SO4-• was transformed to chlorine radicals (Cl•/Cl2-•), phosphate radicals (HPO4-•), and carbonate radicals (CO3-•). Furthermore, the overlapping 95 % confidence intervals (C.I.) and the statistical tests (p > 0.05) both agree that Cl- and HPO42- gain identical ε values. Nevertheless, when HCO3- coexisted in the UV/PS system, the ε values were distinct. The addition of HCO3- would result in ε variation of TCEP in the UV activated PS process, which should receive more attention when applying remediation.
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Affiliation(s)
- Jia Liu
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China.
| | - Liuqing Wei
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Dan Zhang
- School of Energy & Environment, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Liang Tang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Yaqing Liu
- College of light industry and food engineering, Guangxi University, Nanning 530004, China
| | - Liandong Jing
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Junfei Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Shengtao Yang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
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11
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Junginger T, Payraudeau S, Imfeld G. Transformation and stable isotope fractionation of the urban biocide terbutryn during biodegradation, photodegradation and abiotic hydrolysis. CHEMOSPHERE 2022; 305:135329. [PMID: 35709839 DOI: 10.1016/j.chemosphere.2022.135329] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/09/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Terbutryn is a widely used biocide in construction materials like paint and render to prevent the growth of microorganisms, algae and fungi. Terbutryn is released from the facades into the environment during rainfall, contaminating surface waters, soil and groundwater. Knowledge of terbutryn dissipation from the facades to aquatic ecosystems is scarce. Here, we examined in laboratory microcosms degradation half-lives, formation of transformation products and carbon and nitrogen isotope fractionation during terbutryn direct (UV light with λ = 254 nm and simulated sunlight) and indirect (simulated sunlight with nitrate) photodegradation, abiotic hydrolysis (pH = 1, 7 and 13), and aerobic biodegradation (stormwater pond sediment, soil and activated sludge). Biodegradation half-lives of terbutryn were high (>80 d). Photodegradation under simulated sunlight and hydrolysis at extreme pH values indicated slow degradability and accumulation in the environment. Photodegradation resulted in a variety of transformation products, whereas abiotic hydrolysis lead solely to terbutryn-2-hydroxy in acidic and basic conditions. Biodegradation indicates degradation to terbutryn-2-hydroxy through terbutryn-sulfoxide. Compound-specific isotope analysis (CSIA) of terbutryn holds potential to differentiate degradation pathways. Carbon isotope fractionation values (εC) ranged from -3.4 ± 0.3‰ (hydrolysis pH 1) to +0.8 ± 0.1‰ (photodegradation under UV light), while nitrogen isotope fractionation values ranged from -1.0 ± 0.4‰ (simulated sunlight photodegradation with nitrate) to +3.4 ± 0.2‰ (hydrolysis at pH 1). In contrast, isotope fractionation during biodegradation was insignificant. ΛN/C values ranged from -1.0 ± 0.1 (hydrolysis at pH 1) to 2.8 ± 0.3 (photodegradation under UV light), allowing to differentiate degradation pathways. Combining the formation of transformation products and stable isotope fractionation enabled identifying distinct degradation pathways. Altogether, this study highlights the potential of CSIA to follow terbutryn degradation in situ and differentiate prevailing degradation pathways, which may help to monitor urban biocide remediation and mitigation strategies.
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Affiliation(s)
- Tobias Junginger
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg/ EOST/ ENGEES, CNRS, UMR 7063, F-67084, Strasbourg, France
| | - Sylvain Payraudeau
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg/ EOST/ ENGEES, CNRS, UMR 7063, F-67084, Strasbourg, France
| | - Gwenaël Imfeld
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg/ EOST/ ENGEES, CNRS, UMR 7063, F-67084, Strasbourg, France.
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12
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Phillips E, Bulka O, Picott K, Kümmel S, Edwards E, Nijenhuis I, Gehre M, Dworatzek S, Webb J, Lollar BS. Investigation of Active Site Amino Acid Influence on Carbon and Chlorine Isotope Fractionation during Reductive Dechlorination. FEMS Microbiol Ecol 2022; 98:6608266. [PMID: 35700008 DOI: 10.1093/femsec/fiac072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 05/23/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
Reductive dehalogenases (RDases) are corrinoid-dependent enzymes that reductively dehalogenate organohalides in respiratory processes. By comparing isotope effects in biotically-catalyzed reactions to reference experiments with abiotic corrinoid-catalysts, compound-specific isotope analysis (CSIA) has been shown to yield valuable insights into enzyme mechanisms and kinetics, including RDases. Here, we report isotopic fractionation (ε) during biotransformation of chloroform (CF) for carbon (εC = -1.52 ± 0.34‰) and chlorine (εCl = -1.84 ± 0.19‰), corresponding to a ΛC/Cl value of 1.13 ± 0.35. These results are highly suppressed compared to isotope effects observed both during CF biotransformation by another organism with a highly similar RDase (> 95% sequence identity) at the amino acid level, and to those observed during abiotic dehalogenation of CF. Amino acid differences occur at four locations within the two different RDases' active sites, and this study examines whether these differences potentially affect the observed εC, εCl, and ΛC/Cl. Structural protein models approximating the locations of the residues elucidate possible controls on reaction mechanisms and/or substrate binding efficiency. These four locations are not conserved among other chloroalkane reducing RDases with high amino acid similarity (> 90%), suggesting that these locations may be important in determining isotope fractionation within this homologous group of RDases.
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Affiliation(s)
- Elizabeth Phillips
- Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario M5S 3B1, Canada
| | - Olivia Bulka
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Katherine Picott
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Elizabeth Edwards
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Ivonne Nijenhuis
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Matthias Gehre
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany
| | | | | | - Barbara Sherwood Lollar
- Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario M5S 3B1, Canada
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13
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Soder-Walz JM, Torrentó C, Algora C, Wasmund K, Cortés P, Soler A, Vicent T, Rosell M, Marco-Urrea E. Trichloromethane dechlorination by a novel Dehalobacter sp. strain 8M reveals a third contrasting C and Cl isotope fractionation pattern within this genus. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 813:152659. [PMID: 34954170 DOI: 10.1016/j.scitotenv.2021.152659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
Trichloromethane (TCM) is a pollutant frequently detected in contaminated aquifers, and only four bacterial strains are known to respire it. Here, we obtained a novel Dehalobacter strain capable of transforming TCM to dichloromethane, which was denominated Dehalobacter sp. strain 8M. Besides TCM, strain 8M also completely transformed 1,1,2-trichloroethane to vinyl chloride and 1,2-dichloroethane. Quantitative PCR analysis for the 16S rRNA genes confirmed growth of Dehalobacter with TCM and 1,1,2-trichloroethane as electron acceptors. Carbon and chlorine isotope fractionation during TCM transformation was studied in cultured cells and in enzymatic assays with cell suspensions and crude protein extracts. TCM transformation in the three studied systems resulted in small but significant carbon (εC = -2.7 ± 0.1‰ for respiring cells, -3.1 ± 0.1‰ for cell suspensions, and - 4.1 ± 0.5‰ for crude protein extracts) and chlorine (εCl = -0.9 ± 0.1‰, -1.1 ± 0.1‰, and - 1.2 ± 0.2‰, respectively) isotope fractionation. A characteristic and consistent dual CCl isotope fractionation pattern was observed for the three systems (combined ΛC/Cl = 2.8 ± 0.3). This ΛC/Cl differed significantly from previously reported values for anaerobic dechlorination of TCM by the corrinoid cofactor vitamin B12 and other Dehalobacter strains. These findings widen our knowledge on the existence of different enzyme binding mechanisms underlying TCM-dechlorination within the genus Dehalobacter and demonstrates that dual isotope analysis could be a feasible tool to differentiate TCM degraders at field studies.
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Affiliation(s)
- Jesica M Soder-Walz
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Clara Torrentó
- Grup MAiMA, Mineralogia Aplicada, Geoquímica i Geomicrobiologia, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028 Barcelona, Spain
| | - Camelia Algora
- Laboratory of Environmental Microbiology, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220, Praha 4, Czech Republic
| | - Kenneth Wasmund
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1010, Austria
| | - Pilar Cortés
- Departament de Genètica i de Microbiologia, Facultat de BioCiències, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Albert Soler
- Grup MAiMA, Mineralogia Aplicada, Geoquímica i Geomicrobiologia, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028 Barcelona, Spain
| | - Teresa Vicent
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
| | - Mònica Rosell
- Grup MAiMA, Mineralogia Aplicada, Geoquímica i Geomicrobiologia, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028 Barcelona, Spain.
| | - Ernest Marco-Urrea
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, Bellaterra, Spain
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14
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Gilevska T, Sullivan Ojeda A, Kümmel S, Gehre M, Seger E, West K, Morgan SA, Mack EE, Sherwood Lollar B. Multi-element isotopic evidence for monochlorobenzene and benzene degradation under anaerobic conditions in contaminated sediments. WATER RESEARCH 2021; 207:117809. [PMID: 34741903 DOI: 10.1016/j.watres.2021.117809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/10/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Industrial chemicals are frequently detected in sediments due to a legacy of chemical spills. Globally, site remedies for groundwater and sediment decontamination include natural attenuation by in situ abiotic and biotic processes. Compound-specific isotope analysis (CSIA) is a diagnostic tool to identify, quantify, and characterize degradation processes in situ, and in some cases can differentiate between abiotic degradation and biodegradation. This study reports high-resolution carbon, chlorine, and hydrogen stable isotope profiles for monochlorobenzene (MCB), and carbon and hydrogen stable isotope profiles for benzene, coupled with measurements of pore water concentrations in contaminated sediments. Multi-element isotopic analysis of δ13C and δ37Cl for MCB were used to generate dual-isotope plots, which for 2 locations at the study site resulted in ΛC/Cl(130) values of 1.42 ± 0.19 and ΛC/Cl(131) values of 1.70 ± 0.15, consistent with theoretical calculations for carbon-chlorine bond cleavage (ΛT = 1.80 ± 0.31) via microbial reductive dechlorination. For benzene, significant δ2H (122‰) and δ13C (6‰) depletion trends, followed by enrichment trends in δ13C (1.6‰) in the upper part of the sediment, were observed at the same location, indicating not only production of benzene due to biodegradation of MCB, but subsequent biotransformation of benzene itself to nontoxic end-products. Degradation rate constants calculated independently using chlorine isotopic data and carbon isotopic data, respectively, agreed within uncertainty thus providing multiple lines of evidence for in situ contaminant degradation via reductive dechlorination and providing the foundation for a novel approach to determine site-specific in situ rate estimates essential for the prediction of remediation outcomes and timelines.
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Affiliation(s)
- Tetyana Gilevska
- Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada; CNRS/EOST, ITES UMR 7063, Earth and Environment Institute of Strasbourg (ITES), University of Strasbourg, Strasbourg, 67084, France
| | - Ann Sullivan Ojeda
- Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada; Department of Geosciences, Auburn University, Auburn, AL 36849, United States
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research, UFZ, Leipzig, 04318, Germany
| | - Matthias Gehre
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research, UFZ, Leipzig, 04318, Germany
| | - Edward Seger
- The Chemours Company, Wilmington, DE 19810, United States
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15
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Drouin G, Droz B, Leresche F, Payraudeau S, Masbou J, Imfeld G. Direct and indirect photodegradation of atrazine and S-metolachlor in agriculturally impacted surface water and associated C and N isotope fractionation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1791-1802. [PMID: 34709265 DOI: 10.1039/d1em00246e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Knowledge of direct and indirect photodegradation of pesticides and associated isotope fractionation can help to assess pesticide degradation in surface waters. Here, we investigated carbon (C) and nitrogen (N) isotope fractionation during direct and indirect photodegradation of the herbicides atrazine and S-metolachlor in synthetic agriculturally impacted surface waters containing nitrates (20 mg L-1) and dissolved organic matter (DOM, 5.4 mgC L-1). Atrazine and S-metolachlor were quickly photodegraded by both direct and indirect processes (half-lives <5 and <7 days, respectively). DOM slowed down photodegradation while nitrates increased degradation rates. The analysis of transformation products showed that oxidation mediated by hydroxyl radicals (HO˙) predominated during indirect photodegradation. UV light (254 nm) led to significant C and N isotope fractionation, yielding isotopic fractionation values εC = 2.7 ± 0.3 and 0.8 ± 0.1‰, and εN = 2.4 ± 0.3 and -2.6 ± 0.7‰ for atrazine and S-metolachlor, respectively. In contrast, photodegradation under simulated sunlight led to negligible C and slight N isotope fractionation, emphasizing the effect of the radiation wavelengths on the isotope fractionation induced by direct photodegradation. Altogether, these results highlight the importance of using simulated sunlight to obtain environmentally-relevant isotopic fractionation values and to distinguish photodegradation and other dissipation pathways in surface waters.
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Affiliation(s)
- Guillaume Drouin
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Boris Droz
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Frank Leresche
- Department of Civil, Environmental, and Architectural Engineering, Environmental Engineering Program, University of Colorado Boulder, Colorado 80309, USA
| | - Sylvain Payraudeau
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Jérémy Masbou
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Gwenaël Imfeld
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
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16
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Torrentó C, Ponsin V, Lihl C, Hofstetter TB, Baran N, Elsner M, Hunkeler D. Triple-Element Compound-Specific Stable Isotope Analysis (3D-CSIA): Added Value of Cl Isotope Ratios to Assess Herbicide Degradation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13891-13901. [PMID: 34586806 DOI: 10.1021/acs.est.1c03981] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Multielement isotope fractionation studies to assess pollutant transformation are well-established for point-source pollution but are only emerging for diffuse pollution by micropollutants like pesticides. Specifically, chlorine isotope fractionation is hardly explored but promising, because many pesticides contain only few chlorine atoms so that "undiluted" position-specific Cl isotope effects can be expected in compound-average data. This study explored combined Cl, N, and C isotope fractionation to sensitively detect biotic and abiotic transformation of the widespread herbicides and groundwater contaminants acetochlor, metolachlor, and atrazine. For chloroacetanilides, abiotic hydrolysis pathways studied under acidic, neutral, and alkaline conditions as well as biodegradation in two soils resulted in pronounced Cl isotope fractionation (εCl from -5.0 ± 2.3 to -6.5 ± 0.7‰). The characteristic dual C-Cl isotope fractionation patterns (ΛC-Cl from 0.39 ± 0.15 to 0.67 ± 0.08) reveal that Cl isotope analysis provides a robust indicator of chloroacetanilide degradation. For atrazine, distinct ΛC-Cl values were observed for abiotic hydrolysis (7.4 ± 1.9) compared to previous reports for biotic hydrolysis and oxidative dealkylation (1.7 ± 0.9 and 0.6 ± 0.1, respectively). The 3D isotope approach allowed differentiating transformations that would not be distinguishable based on C and N isotope data alone. This first data set on Cl isotope fractionation in chloroacetanilides, together with new data in atrazine degradation, highlights the potential of using compound-specific chlorine isotope analysis for studying in situ pesticide degradation.
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Affiliation(s)
- Clara Torrentó
- Centre of Hydrogeology and Geothermics (CHYN), University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Violaine Ponsin
- Centre of Hydrogeology and Geothermics (CHYN), University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Christina Lihl
- Institute of Groundwater Ecology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Thomas B Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Nicole Baran
- BRGM, Bureau de Recherches Géologiques et Minières, 45060 Cedex 02 Orléans, France
| | - Martin Elsner
- Institute of Groundwater Ecology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
- Technical University of Munich, Chair of Analytical Chemistry and Water Chemistry, 81377 Munich, Germany
| | - Daniel Hunkeler
- Centre of Hydrogeology and Geothermics (CHYN), University of Neuchâtel, 2000 Neuchâtel, Switzerland
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17
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Wu L, Suchana S, Flick R, Kümmel S, Richnow H, Passeport E. Carbon, hydrogen and nitrogen stable isotope fractionation allow characterizing the reaction mechanisms of 1H-benzotriazole aqueous phototransformation. WATER RESEARCH 2021; 203:117519. [PMID: 34391022 DOI: 10.1016/j.watres.2021.117519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/13/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
1H-benzotriazole is part of a larger family of benzotriazoles, which are widely used as lubricants, polymer stabilizers, corrosion inhibitors, and anti-icing fluid components. It is frequently detected in urban runoff, wastewater, and receiving aquatic environments. 1H-benzotriazole is typically resistant to biodegradation and hydrolysis, but can be transformed via direct photolysis and photoinduced mechanisms. In this study, the phototransformation mechanisms of 1H-benzotriazole were characterized using multi-element compound-specific isotope analysis (CSIA). The kinetics, transformation products, and isotope fractionation results altogether revealed that 1H-benzotriazole direct photolysis and indirect photolysis induced by OH radicals involved two alternative pathways. In indirect photolysis, aromatic hydroxylation dominated and was associated with small carbon (εC = -0.65 ± 0.03‰), moderate hydrogen (εH = -21.6‰), and negligible nitrogen isotope enrichment factors and led to hydroxylated forms of benzotriazole. In direct photolysis of 1H-benzotriazole, significant nitrogen (εN = -8.4 ± 0.4 to -4.2 ± 0.3‰) and carbon (εC = -4.3 ± 0.2 to -1.64 ± 0.04‰) isotope enrichment factors indicated an initial N-N bond cleavage followed by nitrogen elimination with a C-N bond cleavage. The results of this study highlight the potential for multi-element CSIA application to track 1H-benzotriazole degradation in aquatic environments.
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Affiliation(s)
- Langping Wu
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON M5S 1A4, Canada
| | - Shamsunnahar Suchana
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON M5S 1A4, Canada
| | - Robert Flick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Hans Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Elodie Passeport
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON M5S 1A4, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada.
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18
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Wang C, Fuller ME, Heraty LJ, Hatzinger PB, Sturchio NC. Photocatalytic mechanisms of 2,4-dinitroanisole degradation in water deciphered by C and N dual-element isotope fractionation. JOURNAL OF HAZARDOUS MATERIALS 2021; 411:125109. [PMID: 33858090 DOI: 10.1016/j.jhazmat.2021.125109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/16/2020] [Accepted: 01/10/2021] [Indexed: 06/12/2023]
Abstract
In surface water environments, photodegradation may be an important process for the natural attenuation of 2,4-dinitroanisole (DNAN). Understanding the photolysis and photocatalysis mechanisms of DNAN is difficult because the photosensitivity of nitro groups and the behavior of DNAN as a potential photosensitizer are unclear in aqueous solutions. Here, we investigate the degradation mechanisms of DNAN under UV-A (λ ~ 350 nm) and UV-C (λ ~ 254 nm) irradiation in a photolysis reactor where aqueous solution was continuously recycled through a UV-irradiated volume from a non-irradiated external reservoir. By tracking C and N isotopic fractionation in DNAN and its reaction products, we observed normal 13C fractionation (εC = -3.34‰) and inverse 15N fractionation (εN = +12.30‰) under UV-A (λ ~ 350 nm) irradiation, in contrast to inverse 13C fractionation (εC = +1.45‰) and normal 15N fractionation (εN = -3.79‰) under UV-C (λ ~ 254 nm) irradiation. These results indicate that DNAN can act as a photosensitizer and may follow a product-to-parent reversion mechanism in surface water environments. The data also indicate that photocatalytic degradation of DNAN in aqueous systems can be monitored via C and N stable isotope analysis.
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Affiliation(s)
- Chunlei Wang
- Department of Earth Sciences, University of Delaware, Newark, DE 19716, USA.
| | - Mark E Fuller
- Aptim Federal Services, LLC, Lawrenceville, NJ 08648, USA
| | - Linnea J Heraty
- Department of Earth Sciences, University of Delaware, Newark, DE 19716, USA
| | | | - Neil C Sturchio
- Department of Earth Sciences, University of Delaware, Newark, DE 19716, USA
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19
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Feng JR, Ni HG. A modified method to calculate dual-isotope slopes for the natural attenuation of organic pollutants in the environment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:30399-30408. [PMID: 33963995 DOI: 10.1007/s11356-021-14313-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 05/03/2021] [Indexed: 06/12/2023]
Abstract
Two-dimensional compound-specific isotope analysis has become a powerful tool for distinguishing reaction mechanisms. Lambda (Λ), an essential and important parameter for processing two-dimensional isotope fractionation data, exhibits values specific to a reaction mechanism. In the present article, we modified the existing algorithms for calculation of lambdas based on a review of current methods. Specifically, by regressing [(1000+δE0,2)*(n1*x2)*ΔδEbulk,1] versus [(1000+δE0,1)*(n2*x1)*ΔδEbulk,2] by the York method, a novel method was developed to calculate Λs. The improved method eliminates both the influence of the nonreacting position and the initial isotope signatures. Furthermore, this method retains the advantages of a two-dimensional isotope plot, which eliminates contributions from commitment to catalysis, does not require determination of the fraction of remaining substrate, and can be constructed even from field data. Additionally, the one-sample t test is applied to generate a 95% confidence interval of the dataset of Λris for various reaction mechanisms. The ranges of 5.67-24.8, 8.54-9.80, 0.51-8.35, 25.2-36.8, and 7.09-21.9 are applicable for the oxidation of C-H bonds (ZC=1, ZH=3; ZC and ZH are the number of indistinguishable carbon and hydrogen atoms in intramolecular competition, respectively), oxidation of C-H bonds (ZC=1, ZH=4), aerobic biodegradation of benzene (ZC=6, ZH=6), methanogenic or sulfate-reducing biodegradation of benzene (ZC=6, ZH=6), and nitrate-reducing biodegradation of benzene (ZC=6, ZH=6). The accumulation and correction of these values will make the data measured in the field easier to interpret.
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Affiliation(s)
- Jin-Ru Feng
- School of Urban Planning and Design, Shenzhen Graduate School, Peking University, Shenzhen, 518055, People's Republic of China
| | - Hong-Gang Ni
- School of Urban Planning and Design, Shenzhen Graduate School, Peking University, Shenzhen, 518055, People's Republic of China.
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20
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Ojeda AS, Zheng J, Phillips E, Sherwood Lollar B. Implications of regression bias for multi-element isotope analysis for environmental remediation. Talanta 2021; 226:122113. [PMID: 33676669 DOI: 10.1016/j.talanta.2021.122113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 11/24/2022]
Abstract
Measuring changes in the stable isotope ratios of multiple elements (e.g. Δδ13C, Δδ37Cl, and Δδ2H) during the (bio)transformation of environmental contaminants has provided new insights into reaction mechanisms and tools to optimize remediation efforts. Dual-isotope analysis, wherein changes in one isotopic system are plotted against another (to derive an interpretational parameter expressed as Λ), is a key tool in multi-element isotopic assessment. To date, most dual-isotope analyses use ordinary linear regression (OLR) for the calculation, which can be subject to regression attenuation and thus an inherent artifact that depresses slope values, expressed as Λ. Here, a series of Monte Carlo simulations were constructed to represent common data conditions and variations within dual-isotope data to test the degree of bias when deriving Λ using OLR compared to an alternative regression technique, the York method. The degree of bias was quantified compared to the modeled or "true" Λ value. For all simulations, the York method provided the least bias in slope estimates (<1%) over all data conditions tested. In contrast, OLR produced unbiased estimates only under a limited set of conditions, which was validated through a mathematical model proof. Both the mathematical model and simulations show that bias of at least 5% in OLR occurs when the extent of enrichment in the x-variable (XM) is equal to or less than ≈15 times the 1σ precision in the isotope measurement (σX), for both Cl/C and C/H plots. The results give practitioners tools to evaluate whether bias is present in data and to estimate the extent to which this negatively impacts the interpretations and predictions of remediation potential for new and previously published datasets. This study demonstrates that integration of such robust statistical tools is essential for dual-isotope interpretations widely used in contaminant hydrogeology but relevant to other disciplines including environmental chemistry and ecology.
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Affiliation(s)
| | - Jingyi Zheng
- Auburn University, Department of Mathematics and Statistics, Auburn, AL, 36849, USA
| | - Elizabeth Phillips
- University of Toronto, Department of Earth Sciences, Toronto, ON, M5S 3B1, Canada
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21
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Höhener P, Imfeld G. Quantification of Lambda (Λ) in multi-elemental compound-specific isotope analysis. CHEMOSPHERE 2021; 267:129232. [PMID: 33338724 DOI: 10.1016/j.chemosphere.2020.129232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
In multi-elemental compound-specific isotope analysis the lambda (Λ) value expresses the isotope shift of one element versus the isotope shift of a second element. In dual-isotope plots, the slope of the regression lines typical reveals the footprint of the underlying isotope effects allowing to distinguish degradation pathways of an organic contaminant molecule in the environment. While different conventions and fitting procedures are used in the literature to determine Λ, it remains unclear how they affect the magnitude of Λ. Here we generate synthetic data for benzene δ2H and δ13C with two enrichment factors εH and εC using the Rayleigh equation to examine how different conventions and linear fitting procedures yield distinct Λ. Fitting an error-free data set in a graph plotting the δ2H versus δ13C overestimates Λ by 0.225%⋅εH/εC, meaning that if εH/εCis larger than 22, Λ is overestimated by more than 5%. The correct fitting of Λ requires a natural logarithmic transformation of δ2H versus δ13C data. Using this transformation, the ordinary linear regression (OLR), the reduced major-axis (RMA) and the York methods find the correct Λ, even for large εH/εC. Fitting a dataset with synthetic data with typical random errors let to the same conclusion and positioned the suitability of each regression method. We conclude that fitting of non-transformed δ values should be discontinued. The validity of most previous Λ values is not compromised, although previously obtained Λ values for large εH/εC could be corrected using our error estimation to improve comparison.
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Affiliation(s)
- Patrick Höhener
- Aix Marseille University - CNRS, UMR 7376, Laboratory of Environmental Chemistry, Marseille, France.
| | - Gwenaël Imfeld
- Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), Université de Strasbourg, UMR 7517 CNRS/EOST, 1 Rue Blessig, 67084, Strasbourg Cedex, France
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22
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Berens MJ, Hofstetter TB, Bolotin J, Arnold WA. Assessment of 2,4-Dinitroanisole Transformation Using Compound-Specific Isotope Analysis after In Situ Chemical Reduction of Iron Oxides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5520-5531. [PMID: 32275413 DOI: 10.1021/acs.est.9b07616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ferrous iron-bearing minerals are important reductants in the contaminated subsurface, but their availability for the reduction of anthropogenic pollutants is often limited by competition with other electron acceptors including microorganisms and poor accessibility to Fe(II) in complex hydrogeologic settings. The supply of external electron donors through in situ chemical reduction (ISCR) has been proposed as one remediation approach, but the quantification of pollutant transformation is complicated by the perturbations introduced to the subsurface by ISCR. Here, we evaluate the application of compound specific isotope analysis (CSIA) for monitoring the reduction of 2,4-dinitroanisole (DNAN), a component of insensitive munitions formulations, by mineral-bound Fe(II) generated through ISCR of subsurface material from two field sites. Electron balances from laboratory experiments in batch and column reactors showed that 3.6% to 11% of the total Fe in the sediments was available for the reduction of DNAN and its partially reduced intermediates after dithionite treatment. The extent of DNAN reduction was successfully quantified from its N isotope fractionation measured in the column effluent based on the derivation of a N isotope enrichment factor, εN, derived from a comprehensive series of isotope fractionation experiments with numerous Fe(II)-bearing minerals as well as dithionite-reduced subsurface materials. Our observations illustrate the utility of CSIA as a robust approach to evaluate the success of in situ remediation through abiotic contaminant reduction.
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Affiliation(s)
- Matthew J Berens
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, United States
| | - Thomas B Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Chemistry, Überlandstrasse 133, CH-8600 Dübendorf , Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Jakov Bolotin
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Chemistry, Überlandstrasse 133, CH-8600 Dübendorf , Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
| | - William A Arnold
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, United States
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23
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Zimmermann J, Halloran LJS, Hunkeler D. Tracking chlorinated contaminants in the subsurface using compound-specific chlorine isotope analysis: A review of principles, current challenges and applications. CHEMOSPHERE 2020; 244:125476. [PMID: 31830644 DOI: 10.1016/j.chemosphere.2019.125476] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
Many chlorinated hydrocarbons have gained notoriety as persistent organic pollutants in the environment. Engineered and natural remediation efforts require a monitoring tool to track the progress of degradation processes. Compound-specific isotope analysis (CSIA) is a robust method to evaluate the origin and fate of contaminants in the environment and does not rely on concentration measurements. While carbon CSIA has established itself in the routine assessment of contaminated sites, studies incorporating chlorine isotopes have only recently become more common. Although some aspects of chlorine isotope analysis are more challenging than carbon isotope analysis, having additional isotopic data yields valuable information for contaminated site management. This review provides an overview of chlorine isotope fractionation of chlorinated contaminants in the subsurface by different processes and presents analytical techniques and unresolved challenges in chlorine isotope analysis. A summary of successful field applications illustrates the potential of using chlorine isotope data. Finally, approaches in modelling chlorine isotope fractionation due to degradation, diffusion, and sorption processes are discussed.
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Affiliation(s)
- Jeremy Zimmermann
- Centre for Hydrogeology and Geothermics, University of Neuchâtel, Rue Emile-Argand 11, CH-2000, Neuchâtel, Switzerland.
| | - Landon J S Halloran
- Centre for Hydrogeology and Geothermics, University of Neuchâtel, Rue Emile-Argand 11, CH-2000, Neuchâtel, Switzerland
| | - Daniel Hunkeler
- Centre for Hydrogeology and Geothermics, University of Neuchâtel, Rue Emile-Argand 11, CH-2000, Neuchâtel, Switzerland
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24
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Ojeda AS, Phillips E, Sherwood Lollar B. Multi-element (C, H, Cl, Br) stable isotope fractionation as a tool to investigate transformation processes for halogenated hydrocarbons. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:567-582. [PMID: 31993605 DOI: 10.1039/c9em00498j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Compound-specific isotope analysis (CSIA) is a powerful tool to evaluate transformation processes of halogenated compounds. Many halogenated hydrocarbons allow for multiple stable isotopic systems (C, H, Cl, Br) to be measured for a single compound. This has led to a large body of literature describing abiotic and biotic transformation pathways and reaction mechanisms for contaminants such as chlorinated alkenes and alkanes as well as brominated hydrocarbons. Here, the current literature is reviewed and a new compilation of Λ values for multi-isotopic systems for halogenated hydrocarbons is presented. Case studies of each compound class are discussed and thereby the current strengths of multi-element isotope analysis, continuing challenges, and gaps in our current knowledge are identified for practitioners of multi-element CSIA to address in the near future.
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Affiliation(s)
- Ann Sullivan Ojeda
- Department of Geosciences, Auburn University, Auburn, Alabama 36849, USA.
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25
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Büsing J, Buchner D, Behrens S, Haderlein SB. Deciphering the Variability of Stable Isotope (C, Cl) Fractionation of Tetrachloroethene Biotransformation by Desulfitobacterium strains Carrying Different Reductive Dehalogenases Enzymes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:1593-1602. [PMID: 31880148 DOI: 10.1021/acs.est.9b05606] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Kinetic isotope effects have been used successfully to prove and characterize organic contaminant transformation on various scales including field and laboratory studies. For tetrachloroethene (PCE) biotransformation, however, causes for the substantial variability of reported isotope enrichment factors (ε) are still not deciphered (εC = -0.4 to -19.0‰). Factors such as different reaction mechanisms and masking of isotope fractionation by either limited intracellular mass transfer or rate-limitations within the enzymatic multistep reaction are under discussion. This study evaluated the contribution of these factors to the magnitude of carbon and chlorine isotope fractionation of Desulfitobacterium strains harboring three different PCE-transforming enzymes (PCE-RdhA). Despite variable single element isotope fractionation (εC = -5.0 to -19.7‰; εCl = -1.9 to -6.3‰), similar slopes of dual element isotope plots (ΛC/Cl values of 2.4 ± 0.1 to 3.6 ± 0.1) suggest a common reaction mechanism for different PCE-RdhAs. Cell envelope properties of the Desulfitobacterium strains allowed to exclude masking effects due to PCE mass transfer limitation. Our results thus revealed that different rate-limiting steps (e.g., substrate channel diffusion) in the enzymatic multistep reactions of individual PCE-RdhAs rather than different reaction mechanisms determine the extent of PCE isotope fractionation in the Desulfitobacterium genus.
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Affiliation(s)
- Johannes Büsing
- Center for Applied Geoscience , University of Tübingen , 72074 Tübingen , Germany
| | - Daniel Buchner
- Center for Applied Geoscience , University of Tübingen , 72074 Tübingen , Germany
| | - Sebastian Behrens
- Department of Civil, Environmental, and Geo-Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Stefan B Haderlein
- Center for Applied Geoscience , University of Tübingen , 72074 Tübingen , Germany
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