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Wang G, Guo P, Liu Y, Li C, Wang X, Wang H. Mechanistic characterization of anaerobic microbial degradation of BTBPE in coastal wetland soils: Implication by compound-specific stable isotope analysis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 335:117622. [PMID: 36867899 DOI: 10.1016/j.jenvman.2023.117622] [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: 12/24/2022] [Revised: 02/06/2023] [Accepted: 02/26/2023] [Indexed: 06/18/2023]
Abstract
As a novel brominate flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) has been extensively used in various consumer products, and frequently detected in various environmental matrices. However, the microbial degradation of BTBPE remains unclear in the environment. This study comprehensively investigated the anaerobic microbial degradation of BTBPE and therein stable carbon isotope effect in the wetland soils. BTBPE degradation followed the pseudo-first-order kinetic, with degradation rate of 0.0085 ± 0.0008 day-1. Based on identification of degradation products, stepwise reductive debromination was the main transformation pathway of BTBPE, and tended to keep the stable of 2,4,6-tribromophenoxy group during the microbial degradation. The pronounced carbon isotope fractionation was observed for BTBPE microbial degradation, and carbon isotope enrichment factor (εC) was determined to be -4.81 ± 0.37‰, indicating cleavage of C-Br bond as the rate-limiting step. Compared to previously reported isotope effects, carbon apparent kinetic isotope effect (AKIEC = 1.072 ± 0.004) suggested that the nucleophilic substitution (SN2 reaction) was the potential reaction mechanism for reductive debromination of BTBPE in the anaerobic microbial degradation. These findings demonstrated that BTBPE could be degraded by the anaerobic microbes in wetland soils, and the compound-specific stable isotope analysis was a robust method to discover the underlying reaction mechanisms.
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Affiliation(s)
- Guoguang Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Pengxu Guo
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Yu Liu
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China; Environmental Information Institute, Dalian Maritime University, Dalian, 116026, China
| | - Chuanyuan Li
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Xu Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Haixia Wang
- Navigation College, Dalian Maritime University, Dalian, 116026, China
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Wang G, Liu Y, Wang X, Dong X, Jiang N, Wang H. Application of dual carbon-bromine stable isotope analysis to characterize anaerobic micro-degradation mechanisms of PBDEs in wetland bottom-water. WATER RESEARCH 2022; 208:117854. [PMID: 34800854 DOI: 10.1016/j.watres.2021.117854] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 11/05/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs), one kind of persistent organic pollutants, were widely detected in coastal wetlands. Microbial reductive debromination is one of the most important attenuation processes for PBDEs in anaerobic environment, whereas the underlying reaction mechanisms remain elusive. Dual-element stable isotope analysis was recently recognized to distinguish different reaction mechanism for degradation of organic pollutants. In this study, the dual carbon-bromine isotope effects associated with the anaerobic microbial degradation were first investigated to characterize the reaction mechanisms for BDE-47 and BDE-153. Presence of lower brominated congeners indicated stepwise debromination as the main degradation pathway, with the preferential removal of bromine in para position > meta/ortho position. The pronounced isotope fractionation was observed for both carbon and bromine, with similar carbon (εC) and bromine isotope enrichment factor (εBr) between BDE-47 (εC = -5.98‰, εBr = -2.44‰) and BDE-153 (εC = -5.57‰, εBr = -2.06‰) during the microbial degradation. Compared to εC and εBr, the correlation of carbon and isotope effects (ΛC/Br = Δδ81Br/Δδ13C) was almost the same between BDE-47 (0.436) and BDE-153 (0.435), indicating the similar reaction mechanism. The calculated carbon and bromine apparent kinetic isotope effects (AKIEC and AKIEBr) were 1.0773 and 1.0098 for BDE-47 and 1.0716 and 1.0125 for BDE-153, within range reported for degradation of halogenated compounds following nucleophilic substitution. Combination analysis of degradation products, ΛC/Br and AKIE, all the results pointed to that the anaerobic reductive debromination of BDE-47 and BDE-153 followed the nucleophilic aromatic substitution, with the addition of cofactor to the benzene ring concomitant with dissociation of carbon-bromine bond via the inner-sphere electron transfer, and the cleavage of C-Br bond was the rate-determining step. This study contributed to the development of dual carbon-bromine isotope analysis as a robust approach to probe the fate of PBDEs in contaminated sites.
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Affiliation(s)
- Guoguang Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Yu Liu
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China; Environmental Information Institute, Dalian Maritime University, Dalian 116026, China.
| | - Xu Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Xu Dong
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Na Jiang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Haixia Wang
- Navigation College, Dalian Maritime University, Dalian 116026, China
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Wang Q, Yang M, Song X, Tang S, Yu L. Aerobic and Anaerobic Biodegradation of 1,2-Dibromoethane by a Microbial Consortium under Simulated Groundwater Conditions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16193775. [PMID: 31597267 PMCID: PMC6802363 DOI: 10.3390/ijerph16193775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 09/24/2019] [Accepted: 09/28/2019] [Indexed: 11/16/2022]
Abstract
This study was conducted to explore the potential for 1,2-Dibromoethane (EDB) biodegradation by an acclimated microbial consortium under simulated dynamic groundwater conditions. The enriched EDB-degrading consortium consisted of anaerobic bacteria Desulfovibrio, facultative anaerobe Chromobacterium, and other potential EDB degraders. The results showed that the biodegradation efficiency of EDB was more than 61% at 15 °C, and the EDB biodegradation can be best described by the apparent pseudo-first-order kinetics. EDB biodegradation occurred at a relatively broad range of initial dissolved oxygen (DO) from 1.2 to 5.1 mg/L, indicating that the microbial consortium had a strong ability to adapt. The addition of 40 mg/L of rhamnolipid and 0.3 mM of sodium lactate increased the biodegradation. A two-phase biodegradation scheme was proposed for the EDB biodegradation in this study: an aerobic biodegradation to carbon dioxide and an anaerobic biodegradation via a two-electron transfer pathway of dihaloelimination. To our knowledge, this is the first study that reported EDB biodegradation by an acclimated consortium under both aerobic and anaerobic conditions, a dynamic DO condition often encountered during enhanced biodegradation of EDB in the field.
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Affiliation(s)
- Qing Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 21008, China.
| | - Miaoyan Yang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 21008, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xin Song
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 21008, China.
| | - Shiyue Tang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 21008, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lei Yu
- Department of Environmental Engineering, Nanjing Forestry University, Nanjing 210037, China.
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Ding S, Wang F, Chu W, Cao Z, Pan Y, Gao N. Rapid degradation of brominated and iodinated haloacetamides with sulfite in drinking water: Degradation kinetics and mechanisms. WATER RESEARCH 2018; 143:325-333. [PMID: 29986242 DOI: 10.1016/j.watres.2018.06.049] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
The effective removal of haloacetamides (HAMs) as a group of emerging disinfection by-products is essential for drinking water safety. This study investigated the degradation of 10 HAMs, including chlorinated, brominated, and iodinated analogues, by sodium sulfite (S(IV)) and the mechanism behind it. The results indicated that all HAMs, excluding chlorinated HAMs, decomposed immediately when exposed to S(IV). The reductive dehalogenation kinetics were well described by a second-order kinetics model, first-order in S(IV) and first-order in HAMs. The degradation rates of HAMs increased with the increase of pH and they were positively correlated with sulfite concentration, indicating that the reaction of S(IV) with HAMs mainly depends on sulfite. The rank order and relative activity of the reaction of sulfite with HAMs depends on bimolecular nucleophilic substitution reaction reactivity. The order of the reductive dehalogenation rates of HAMs versus the substitution of halogen atoms was iodo- > bromo- >> chloro-. During reductive dehalogenation of HAMs by sulfite, the α-carbon bound to the amide group underwent nucleophilic attack at 180° to the leaving group (halide). As a consequence, the halide was pushed off the opposite side, generating a transition state pentacoordinate. The breaking of the C-X bond and the formation of the new C-S bond occurred simultaneously and HAM sulfonate formed as the immediate product. Results suggest that S(IV) can be used to degrade brominated and iodinated HAMs in drinking water and therefore should not be added as a quenching agent before HAM analysis to accurately determine the HAM concentrations produced during water disinfection.
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Affiliation(s)
- Shunke Ding
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Feifei Wang
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, PO Box 5048, 2600 GA Delft, the Netherlands
| | - Wenhai Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
| | - Zhongqi Cao
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yang Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu province, China
| | - Naiyun Gao
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
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Jin B, Nijenhuis I, Rolle M. Simulation of dual carbon-bromine stable isotope fractionation during 1,2-dibromoethane degradation. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2018; 54:418-434. [PMID: 29852794 DOI: 10.1080/10256016.2018.1468759] [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: 11/29/2016] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
We performed a model-based investigation to simultaneously predict the evolution of concentration, as well as stable carbon and bromine isotope fractionation during 1,2-dibromoethane (EDB, ethylene dibromide) transformation in a closed system. The modelling approach considers bond-cleavage mechanisms during different reactions and allows evaluating dual carbon-bromine isotopic signals for chemical and biotic reactions, including aerobic and anaerobic biological transformation, dibromoelimination by Zn(0) and alkaline hydrolysis. The proposed model allowed us to accurately simulate the evolution of concentrations and isotope data observed in a previous laboratory study and to successfully identify different reaction pathways. Furthermore, we illustrated the model capabilities in degradation scenarios involving complex reaction systems. Specifically, we examined (i) the case of sequential multistep transformation of EDB and the isotopic evolution of the parent compound, the intermediate and the reaction product and (ii) the case of parallel competing abiotic pathways of EDB transformation in alkaline solution.
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Affiliation(s)
- Biao Jin
- a Department of Environmental Engineering , Technical University of Denmark , Kgs. Lyngby , Denmark
- b State Key Laboratory of Organic Geochemistry , Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou , People's Republic of China
| | - Ivonne Nijenhuis
- c Department of Isotope Biogeochemistry , Helmholtz Centre for Environmental Research - UFZ , Leipzig , Germany
| | - Massimo Rolle
- a Department of Environmental Engineering , Technical University of Denmark , Kgs. Lyngby , Denmark
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Segal DC, Kuder T, Kolhatkar R. Assessment of anaerobic biodegradation of bis(2-chloroethyl) ether in groundwater using carbon and chlorine compound-specific isotope analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:696-705. [PMID: 29306157 DOI: 10.1016/j.scitotenv.2017.12.246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/18/2017] [Accepted: 12/21/2017] [Indexed: 06/07/2023]
Abstract
Carbon and chlorine compound specific isotope analysis (CSIA) of bis(2-chloroethyl) ether (BCEE) was performed to distinguish the primary processes contributing to observed concentration reductions in an anaerobic groundwater plume. Laboratory microcosms were constructed to demonstrate and obtain isotopic enrichment factors and dual-element CSIA trends from two potential transformation processes (1) anaerobic biodegradation using saturated sediment samples from the field site (εC=-14.8 and εCl=-5.0) and (2) abiotic reactions with sulfide nucleophiles in water (εC=-12.8 and εCl=-5.0). The results suggested a nucleophilic, SN2-type dechlorination as the mechanism of biodegradation of BCEE. Identical dual-element CSIA trends observed in the field and in the microcosm samples suggested that the same degradation mechanism was responsible for BCEE degradation in the field. While biodegradation was the likely dominant mechanism of BCEE mass destruction in the aquifer, potential contribution of abiotic hydrolysis to the net budget of degradation could not be confidently excluded. To our knowledge, this is the first unequivocal demonstration of BCEE biodegradation at a field site.
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Affiliation(s)
- Daniel C Segal
- Chevron Energy Technology Company, San Ramon, CA, United States
| | - Tomasz Kuder
- School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States
| | - Ravi Kolhatkar
- Chevron Energy Technology Company, Houston, TX, United States.
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7
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Koster van Groos PG, Hatzinger PB, Streger SH, Vainberg S, Philp RP, Kuder T. Carbon Isotope Fractionation of 1,2-Dibromoethane by Biological and Abiotic Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3440-3448. [PMID: 29493235 DOI: 10.1021/acs.est.7b05224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Affiliation(s)
- Paul G. Koster van Groos
- Biotechnology Development and Applications Group, APTIM, 17 Princess Road, Lawrenceville, New Jersey 08648, United States
| | - Paul B. Hatzinger
- Biotechnology Development and Applications Group, APTIM, 17 Princess Road, Lawrenceville, New Jersey 08648, United States
| | - Sheryl H. Streger
- Biotechnology Development and Applications Group, APTIM, 17 Princess Road, Lawrenceville, New Jersey 08648, United States
| | - Simon Vainberg
- Biotechnology Development and Applications Group, APTIM, 17 Princess Road, Lawrenceville, New Jersey 08648, United States
| | - R. Paul Philp
- School of Geology and Geophysics, University of Oklahoma, 100 E. Boyd Street SEC 710, Norman, Oklahoma 73019, United States
| | - Tomasz Kuder
- School of Geology and Geophysics, University of Oklahoma, 100 E. Boyd Street SEC 710, Norman, Oklahoma 73019, United States
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Sohn SY, Kuntze K, Nijenhuis I, Häggblom MM. Evaluation of carbon isotope fractionation during anaerobic reductive dehalogenation of chlorinated and brominated benzenes. CHEMOSPHERE 2018; 193:785-792. [PMID: 29175406 DOI: 10.1016/j.chemosphere.2017.11.089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 11/15/2017] [Accepted: 11/18/2017] [Indexed: 06/07/2023]
Abstract
Compound specific stable isotope analysis (CSIA) has been established as a useful tool to evaluate in situ biodegradation. Here, CSIA was used to determine microbial dehalogenation of chloro- and bromobenzenes in microcosms derived from Hackensack River sediments. Gas chromatography-isotope ratio mass spectrometry (GC-IRMS) was used to measure carbon isotope fractionation during reductive dehalogenation of hexachlorobenzene (HCB), pentachlorobenzene (PeCB), 1,2,3,5-tetrachlorobenzene (TeCB), 1,2,3,5-tetrabromobenzene (TeBB), and 1,3,5-tribromobenzene (TriBB). Strong evidence of isotope fractionation coupled to dehalogenation was not observed in the substrate, possibly due to the low solubilities of the highly halogenated benzene substrates and a dilution of the isotope signal. Nonetheless, we could measure a depletion of the δ13C value in the dichlorobenzene product during dechlorination of HCB, the sequential depletion and enrichment of δ13C value for trichlorobenzene in TeCB dechlorinating cultures, and the enrichment of δ13C during debromination of TriBB. This indicates that a measurable isotope fractionation occurred during reductive dehalogenation of highly halogenated chloro- and bromobenzenes in aquatic sediments. Thus, although more quantitative measurements will be needed, the data suggests that CSIA may have application for monitoring in situ microbial reductive dehalogenation of highly halogenated benzenes.
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Affiliation(s)
- Seo Yean Sohn
- Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers University, 76 Lipman Drive, New Brunswick, NJ 08901, USA
| | - Kevin Kuntze
- Department of Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, D-04318, Leipzig, Germany
| | - Ivonne Nijenhuis
- Department of Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, D-04318, Leipzig, Germany
| | - Max M Häggblom
- Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers University, 76 Lipman Drive, New Brunswick, NJ 08901, USA.
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Kuntze K, Kozell A, Richnow HH, Halicz L, Nijenhuis I, Gelman F. Dual Carbon-Bromine Stable Isotope Analysis Allows Distinguishing Transformation Pathways of Ethylene Dibromide. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9855-9863. [PMID: 27526716 DOI: 10.1021/acs.est.6b01692] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The present study investigated dual carbon-bromine isotope fractionation of the common groundwater contaminant ethylene dibromide (EDB) during chemical and biological transformations, including aerobic and anaerobic biodegradation, alkaline hydrolysis, Fenton-like degradation, debromination by Zn(0) and reduced corrinoids. Significantly different correlation of carbon and bromine isotope fractionation (ΛC/Br) was observed not only for the processes following different transformation pathways, but also for abiotic and biotic processes with, the presumed, same formal chemical degradation mechanism. The studied processes resulted in a wide range of ΛC/Br values: ΛC/Br = 30.1 was observed for hydrolysis of EDB in alkaline solution; ΛC/Br between 4.2 and 5.3 were determined for dibromoelimination pathway with reduced corrinoids and Zn(0) particles; EDB biodegradation by Ancylobacter aquaticus and Sulfurospirillum multivorans resulted in ΛC/Br = 10.7 and 2.4, respectively; Fenton-like degradation resulted in carbon isotope fractionation only, leading to ΛC/Br ∞. Calculated carbon apparent kinetic isotope effects ((13)C-AKIE) fell with 1.005 to 1.035 within expected ranges according to the theoretical KIE, however, biotic transformations resulted in weaker carbon isotope effects than respective abiotic transformations. Relatively large bromine isotope effects with (81)Br-AKIE of 1.0012-1.002 and 1.0021-1.004 were observed for nucleophilic substitution and dibromoelimination, respectively, and reveal so far underestimated strong bromine isotope effects.
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Affiliation(s)
- Kevin Kuntze
- Department of Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany
| | - Anna Kozell
- Geological Survey of Israel, 30 Malkhei Israel St., Jerusalem, 95501, Israel
| | - Hans H Richnow
- Department of Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany
| | - Ludwik Halicz
- Geological Survey of Israel, 30 Malkhei Israel St., Jerusalem, 95501, Israel
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw , 02-089 Warsaw, Poland
| | - Ivonne Nijenhuis
- Department of Isotope Biogeochemistry, Helmholtz-Centre for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany
| | - Faina Gelman
- Geological Survey of Israel, 30 Malkhei Israel St., Jerusalem, 95501, Israel
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Ma J, Li H, Spiese R, Wilson J, Yan G, Guo S. Vapor intrusion risk of lead scavengers 1,2-dibromoethane (EDB) and 1,2-dichloroethane (DCA). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 213:825-832. [PMID: 27038569 DOI: 10.1016/j.envpol.2016.03.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 03/12/2016] [Accepted: 03/13/2016] [Indexed: 06/05/2023]
Abstract
Vapor intrusion of synthetic fuel additives represented a critical yet still neglected problem at sites impacted by petroleum fuel releases. This study used an advanced numerical model to simulate the vapor intrusion risk of lead scavengers 1,2-dibromoethane (ethylene dibromide, EDB) and 1,2-dichloroethane (DCA) under different site conditions. We found that simulated EDB and DCA indoor air concentrations can exceed USEPA screening level (4.7 × 10(-3) μg/m(3) for EDB and 1.1 × 10(-1) μg/m(3) for DCA) if the source concentration is high enough (is still within the concentration range found at leaking UST site). To evaluate the chance that vapor intrusion of EDB might exceed the USEPA screening levels for indoor air, the simulation results were compared to the distribution of EDB at leaking UST sites in the US. If there is no degradation of EDB or only abiotic degradation of EDB, from 15% to 37% of leaking UST sites might exceed the USEPA screening level. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the screening criteria for petroleum hydrocarbon may not provide sufficient protectiveness for fuel releases containing EDB and DCA. Based on a thorough literature review, we also compiled previous published data on the EDB and DCA groundwater source concentrations and their degradation rates. These data are valuable in evaluating EDB and DCA vapor intrusion risk. In addition, a set of refined attenuation factors based on site-specific information (e.g., soil types, source depths, and degradation rates) were provided for establishing site-specific screening criteria for EDB and DCA. Overall, this study points out that lead scavengers EDB and DCA may cause vapor intrusion problems. As more field data of EDB and DCA become available, we recommend that USEPA consider including these data in the existing PVI database and possibly revising the PVI Guidance as necessary.
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Affiliation(s)
- Jie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China.
| | - Haiyan Li
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Richard Spiese
- Vermont Department of Environmental Conservation, Waste Management & Prevention Division, Montpelier, VT, 05620, USA
| | - John Wilson
- Scissortail Environmental Solutions, LLC., Ada, OK, 74820, USA
| | - Guangxu Yan
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Shaohui Guo
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
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11
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Nunez Garcia A, Boparai HK, O'Carroll DM. Enhanced Dechlorination of 1,2-Dichloroethane by Coupled Nano Iron-Dithionite Treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5243-5251. [PMID: 27128632 DOI: 10.1021/acs.est.6b00734] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
1,2-Dichloroethane (1,2-DCA) is a chlorinated solvent classified as a probable human carcinogen. Due to its extensive use in industrial applications, widespread contamination, and recalcitrance toward abiotic dechlorination, 1,2-DCA remains a challenging compound for the remediation community. Over the past decade, nano zerovalent iron (nZVI) has been efficiently used to treat many of the chlorinated compounds of concern. However, thus far, even nZVI (monometallic or bimetallic) has been unable to dechlorinate 1,2-DCA. Therefore, an alternative treatment coupling nZVI with dithionite to treat 1,2-DCA is proposed in this work. Coupled nZVI-dithionite was able to degrade >90% 1,2-DCA over the course of a year. The effects of dithionite and nZVI loadings, carboxymethyl cellulose (CMC) coating, addition of palladium, and other iron species as metal surfaces on the degradation kinetics were also investigated. Observed pseudo-first-order rate constants (kobs) ranged from 3.8 × 10(-3) to 7.8 × 10(-3) d(-1). Both nucleophilic substitution and reductive dechlorination are the proposed mechanisms for 1,2-DCA degradation by coupled nZVI-dithionite treatment. Characterization analysis of the nZVI-dithionite nanoparticles shows that most of the iron was still preserved in the zerovalent state even after more than one year of reactivity with some iron sulfide (FeS) formation. Scanning electron microscopy (SEM) analysis shows that the nanosized spherical particles were still present along with the FeS platelets. This novel treatment represents the first nZVI-based formulation to achieve nearly complete degradation of 1,2-DCA.
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Affiliation(s)
- Ariel Nunez Garcia
- Civil and Environmental Engineering, Western University , 1151 Richmond Road, London, Ontario N6A 5B8, Canada
| | - Hardiljeet K Boparai
- Civil and Environmental Engineering, Western University , 1151 Richmond Road, London, Ontario N6A 5B8, Canada
| | - Denis M O'Carroll
- Civil and Environmental Engineering, Western University , 1151 Richmond Road, London, Ontario N6A 5B8, Canada
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Kozell A, Yecheskel Y, Balaban N, Dror I, Halicz L, Ronen Z, Gelman F. Application of dual carbon-bromine isotope analysis for investigating abiotic transformations of tribromoneopentyl alcohol (TBNPA). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4433-4440. [PMID: 25723316 DOI: 10.1021/es504887d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Many of polybrominated organic compounds, used as flame retardant additives, belong to the group of persistent organic pollutants. Compound-specific isotope analysis is one of the potential analytical tools for investigating their fate in the environment. However, the isotope effects associated with transformations of brominated organic compounds are still poorly explored. In the present study, we investigated carbon and bromine isotope fractionation during degradation of tribromoneopentyl alcohol (TBNPA), one of the widely used flame retardant additives, in three different chemical processes: transformation in aqueous alkaline solution (pH 8); reductive dehalogenation by zero-valent iron nanoparticles (nZVI) in anoxic conditions; oxidative degradation by H2O2 in the presence of CuO nanoparticles (nCuO). Two-dimensional carbon-bromine isotope plots (δ(13)C/Δ(81)Br) for each reaction gave different process-dependent isotope slopes (Λ(C/Br)): 25.2 ± 2.5 for alkaline hydrolysis (pH 8); 3.8 ± 0.5 for debromination in the presence of nZVI in anoxic conditions; ∞ in the case of catalytic oxidation by H2O2 with nCuO. The obtained isotope effects for both elements were generally in agreement with the values expected for the suggested reaction mechanisms. The results of the present study support further applications of dual carbon-bromine isotope analysis as a tool for identification of reaction pathway during transformations of brominated organic compounds in the environment.
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Affiliation(s)
- Anna Kozell
- †Geological Survey of Israel, 30 Malhei Israel Street, Jerusalem 95501, Israel
- ‡Department of Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Yinon Yecheskel
- §Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Noa Balaban
- ∥Zuckerberg Institute for Water Research, Department of Environmental Hydrology and Microbiology, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Sede Boqer 84990, Israel
| | - Ishai Dror
- §Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ludwik Halicz
- †Geological Survey of Israel, 30 Malhei Israel Street, Jerusalem 95501, Israel
- ⊥Biological and Chemical Research Centre, University of Warsaw, 02-089, Poland
| | - Zeev Ronen
- ∥Zuckerberg Institute for Water Research, Department of Environmental Hydrology and Microbiology, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Sede Boqer 84990, Israel
| | - Faina Gelman
- †Geological Survey of Israel, 30 Malhei Israel Street, Jerusalem 95501, Israel
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