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Luarte T, Hirmas-Olivares A, Höfer J, Giesecke R, Mestre M, Guajardo-Leiva S, Castro-Nallar E, Pérez-Parada A, Chiang G, Lohmann R, Dachs J, Nash SB, Pulgar J, Pozo K, Přibylová PP, Martiník J, Galbán-Malagón C. Occurrence and diffusive air-seawater exchanges of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in Fildes Bay, King George Island, Antarctica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168323. [PMID: 37949125 DOI: 10.1016/j.scitotenv.2023.168323] [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: 05/26/2023] [Revised: 10/31/2023] [Accepted: 11/02/2023] [Indexed: 11/12/2023]
Abstract
We report the levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in seawater and air, and the air-sea dynamics through diffusive exchange analysis in Fildes Bay, King George Island, Antarctica, between November 2019 and January 30, 2020. Hexachlorobenzene (HCB) was the most abundant compound in both air and seawater with concentrations around 39 ± 2.1 pg m-3 and 3.2 ± 2.4 pg L-1 respectively. The most abundant PCB congener was PCB 11, with a mean of 3.16 ± 3.7 pg m-3 in air and 2.0 ± 1.1 pg L-1 in seawater. The fugacity gradient estimated for the OCP compounds indicate a predominance of net atmospheric deposition for HCB, α-HCH, γ-HCH, 4,4'-DDT, 4,4'-DDE and close to equilibrium for the PeCB compound. The observed deposition of some OCs may be driven by high biodegradation rates and/or settling fluxes decreasing the concentration of these compounds in surface waters, which is supported by the capacity of microbial consortium to degrade some of these compounds. The estimated fugacity gradients for PCBs showed differences between congeners, with net volatilization predominating for PCB-9, a trend close to equilibrium for PCB congeners 11, 28, 52, 101, 118, 138, and 153, and deposition for PCB 180. Snow amplification may play an important role for less hydrophobic PCBs, with volatilization predominating after snow/glacier melting. As hydrophobicity increases, the biological pump decreases the concentration of PCBs in seawater, reversing the fugacity gradient to atmospheric deposition. This study highlights the potential impacts of climate change, through glacier retreat, on the biogeochemistry of POPs, remobilizing those compounds previously trapped within the cryosphere which in turn will transform the Antarctic cryosphere into a secondary source of the more volatile POPs in coastal areas, influenced by snow and ice melting.
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Affiliation(s)
- Thais Luarte
- Programa de Doctorado en Medicina de la Conservación, Facultad Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370251, Chile; GEMA, Center for Genomics, Ecology & Environment, Universidad Mayor, Camino La Pirámide, 5750, Huechuraba, Santiago 8580745, Chile; Anillo en Ciencia y Tecnología Antártica POLARIX, Chile; Institute of Environment, Florida International University, University Park, Miami, FL 33199, USA.
| | - Andrea Hirmas-Olivares
- GEMA, Center for Genomics, Ecology & Environment, Universidad Mayor, Camino La Pirámide, 5750, Huechuraba, Santiago 8580745, Chile; Anillo en Ciencia y Tecnología Antártica POLARIX, Chile; Department of Ecology and Biodiversity, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370251, Chile
| | - Juan Höfer
- Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile; Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
| | - Ricardo Giesecke
- Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile; Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Independencia 631, Valdivia, Chile
| | - Mireia Mestre
- Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile; Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain; Centro de Investigación Oceanográfica COPAS COASTAL, Universidad de Concepción, Chile
| | - Sergio Guajardo-Leiva
- Anillo en Ciencia y Tecnología Antártica POLARIX, Chile; Departamento de Microbiología, Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile; Centro de Ecología Integrativa, Universidad de Talca, Campus Lircay, Talca, Chile
| | - Eduardo Castro-Nallar
- Anillo en Ciencia y Tecnología Antártica POLARIX, Chile; Departamento de Microbiología, Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile; Centro de Ecología Integrativa, Universidad de Talca, Campus Lircay, Talca, Chile
| | - Andrés Pérez-Parada
- Departamento de Desarrollo Tecnológico, Centro Universitario Regional del Este (CURE), Universidad de la República, Ruta 9 y Ruta 15, Rocha 27000, Uruguay
| | - Gustavo Chiang
- Department of Ecology and Biodiversity, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370251, Chile; Centro de Investigación para Sustentabilidad, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Rainer Lohmann
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
| | - Jordi Dachs
- Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, Barcelona, Catalunya 08034, Spain
| | - Susan Bengtson Nash
- Southern Ocean Persistent Organic Pollutants Program, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia
| | - José Pulgar
- Department of Ecology and Biodiversity, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370251, Chile
| | - Karla Pozo
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Lientur 1457, Concepción, Chile; Masaryk University, Faculty of Science, RECETOX, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Petra P Přibylová
- Masaryk University, Faculty of Science, RECETOX, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Jakub Martiník
- Masaryk University, Faculty of Science, RECETOX, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Cristóbal Galbán-Malagón
- GEMA, Center for Genomics, Ecology & Environment, Universidad Mayor, Camino La Pirámide, 5750, Huechuraba, Santiago 8580745, Chile; Anillo en Ciencia y Tecnología Antártica POLARIX, Chile; Institute of Environment, Florida International University, University Park, Miami, FL 33199, USA.
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Aamir M, Guo Z, Yu J, Zhao L, Xu D, Sun X, Xu C, Niu L, Liu W. Integrating compound-specific stable isotope and enantiomer-specific analysis to characterize the isomeric and enantiomeric signatures of hexachlorocyclohexanes (HCHs) in paddy soils. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132196. [PMID: 37536155 DOI: 10.1016/j.jhazmat.2023.132196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/21/2023] [Accepted: 07/29/2023] [Indexed: 08/05/2023]
Abstract
Organic pollutants in paddy fields may undergo different processes from those in dryland due to the anaerobic environment. The integrated use of compound-specific stable isotope analysis (CSIA) and enantiomer-specific analysis is a promising technique for understanding the behavior and fate of organic pollutants in soils. In this study, soil samples were collected from paddy fields in three major rice cultivation regions of China, spanning a transect of 4000 km. The mean concentrations of ƩHCHs in paddy soils from the Taihu Plain were the highest (1.44 ng/g). The ratios of α-HCH/β-HCH (all below 11.8) and α-HCH/γ-HCH (92% below 4.64), as well as the enantiomeric fractions (EFs) of chiral α-HCH (mean of 0.81), reflected that the distribution of HCHs was affected by the use of both technical HCHs and lindane. The preferential depletion of (-)-α-HCH and pronounced carbon isotope fractionation of α-HCH (δ13C of -28.22 ± 0.92‰ -23.63 ± 1.89‰) demonstrated its effective transformation. Factors such as altitude, soil temperature, soil pH, soil conductivity and soil organic matter significantly influenced the fate and transformation of HCHs. The current study highlights the integrated application of CSIA and enantiomer-specific analysis to provide multiple lines of evidence for the transformation of HCHs in soils.
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Affiliation(s)
- Muhammad Aamir
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China
| | - Zili Guo
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China
| | - Jiawei Yu
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China; College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, China
| | - Lu Zhao
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China
| | - Dongmei Xu
- College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, China
| | - Xiaohui Sun
- Zhejiang Environmental Monitoring Centre, Hangzhou 310012, China
| | - Chao Xu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Lili Niu
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China.
| | - Weiping Liu
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China; MOE Key Laboratory of Environmental Remediation and Ecosystem Health, Institute of Environmental Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
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Liu X, Yang A, Kümmel S, Richnow HH. Uptake and Metabolization of HCH Isomers in Trees Examined over an Annual Growth Period by Compound-Specific Isotope Analysis and Enantiomer Fractionation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10120-10130. [PMID: 35758406 DOI: 10.1021/acs.est.2c02697] [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] [Indexed: 06/15/2023]
Abstract
To understand the role of plants for natural attenuation, a field study was conducted to characterize the fate of HCH in trees over an annual growth period using compound-specific isotope analysis and enantiomer fractionation. Stable and slightly higher δ13C and δ37Cl values of HCH of host soil samples compared to the muck (consisting nearly exclusively of HCH) revealed that masking isotope effects caused by the limited bioavailability may underestimate the real extent of HCH transformation in soil. In contrast, an increase of δ13C and δ37Cl values in trees indicated the transformation of HCH. A large variability of δ13C and δ37Cl values in trees over the growth period was observed, representing different transformation extents among different growth times, which is further supported by the shift of the enantiomer fraction (EF), indicating the preferential transformation of enantiomers also varied over the different growth periods. Based on dual-element isotope analysis, different predominant transformation mechanisms were observed during the growing seasons. Our observation implies that plants are acting as biological pumps driving a cycle of uptake and metabolization of HCH and refeed during littering to soil catalyzing their transformation. The changes of the transformation mechanism in different seasons have implications for phytoscreening and shed new light on phytoremediation of HCH at field sites.
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Affiliation(s)
- Xiao Liu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Ahyung Yang
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
- The Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, Landau in der Pfalz 76829, Germany
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Hans H Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
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Liu X, Wu L, Kümmel S, Richnow HH. Characterizing the biotransformation of hexachlorocyclohexanes in wheat using compound-specific stable isotope analysis and enantiomer fraction analysis. JOURNAL OF HAZARDOUS MATERIALS 2021; 406:124301. [PMID: 33144013 DOI: 10.1016/j.jhazmat.2020.124301] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 10/10/2020] [Accepted: 10/15/2020] [Indexed: 06/11/2023]
Abstract
Hexachlorocyclohexane isomers (HCHs) are persistent organic pollutants being responsible for environmental contamination worldwide. In order to characterize transformation of HCHs in different plant compartments during uptake, a hydroponic experimental setup was designed using wheat as the test plant. The extent of transformation was determined by using compound-specific isotope analysis (CSIA) and enantiomer fraction (EF) analysis. In nutrient solutions, no change of carbon (δ13C) and chlorine isotope ratios (δ37Cl) of α-HCH and β-HCH was detected throughout the experiment indicating no transformation there. In wheat leaves, stems and roots, however, transformation of α-HCH due to a C‒Cl bond cleavage was indicated by increasing δ13C and δ37Cl compared to the nutrient solution. In addition, 1,3,4,5,6-pentachlorocyclohexene (PCCH) was identified as the major metabolite of α-HCH transformation. For β-HCH, in contrast, no transformation was detected. The evaluation of enantiomer fraction analysis revealed no change of the EF(-) in the nutrient solution or on root surface but a decrease in the wheat compartments, providing an evidence for the preferential biological transformation of (-)α-HCH in wheat. The current study provides the first experimental evidence for biotransformation of α-HCH in wheat using CSIA and EF and provides a concept to evaluate processes during phytoremediation.
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Affiliation(s)
- Xiao Liu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Langping Wu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Department of Civil & Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON M5S 1A4, Canada
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Hans H Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
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5
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Liu X, Wu L, Kümmel S, Merbach I, Lal R, Richnow HH. Compound-Specific Isotope Analysis and Enantiomer Fractionation to Characterize the Transformation of Hexachlorocyclohexane Isomers in a Soil-Wheat Pot System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8690-8698. [PMID: 32543837 DOI: 10.1021/acs.est.9b07609] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The uptake by plants from soil is one of the first steps for hexachlorocyclohexane (HCH) isomers to enter the food web. However, the HCH transformation associated with the uptake process is still not well understood. Therefore, a soil-wheat pot experiment was conducted to characterize the HCH transformation during wheat growth using compound-specific isotope analysis (CSIA) and enantiomer fractionation. The results showed that the δ13C and δ37Cl values of β-HCH remained stable in soil and wheat, revealing no transformation. In contrast, an increase of δ13C and δ37Cl values of α-HCH indicated its transformation in soil and wheat. A shift of the enantiomer fraction (EF) (-) from 0.50 to 0.35 in soil at the jointing stage and 0.35 to 0.57 at the harvest stage suggested that the preferential transformation of enantiomers varied at different growth stages. Based on the dual element isotope analysis, the transformation mechanism in the soil-wheat system was different from that in wheat in hydroponic systems. The high abundance of HCH degraders, Sphingomonas sp. and Novosphingobium sp., was detected in the α-HCH-treated rhizosphere soil, supporting the potential for biotransformation. The application of CSIA and EF allows characterizing the transformation of organic pollutants such as HCHs in the complex soil-plant systems.
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Affiliation(s)
- Xiao Liu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Langping Wu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany
- Department of Civil & Mineral Engineering, University of Toronto, 35 St George Street, Toronto ON M5S 1A4, Canada
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Ines Merbach
- Department of Community Ecology, Helmholtz Centre for Environmental Research GmbH-UFZ, Theodor-Lieser-Str. 4, 06102 Halle, Germany
| | - Rup Lal
- Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi 110007, India
| | - Hans H Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany
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Liu Y, Liu J, Renpenning J, Nijenhuis I, Richnow HH. Dual C-Cl Isotope Analysis for Characterizing the Reductive Dechlorination of α- and γ-Hexachlorocyclohexane by Two Dehalococcoides mccartyi Strains and an Enrichment Culture. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7250-7260. [PMID: 32441516 DOI: 10.1021/acs.est.9b06407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Hexachlorocyclohexanes (HCHs) are persistent organic contaminants that threaten human health. Microbial reductive dehalogenation is one of the most important attenuation processes in contaminated environments. This study investigated carbon and chlorine isotope fractionation of α- and γ-HCH during the reductive dehalogenation by three anaerobic cultures. The presence of tetrachlorocyclohexene (TeCCH) indicated that reductive dichloroelimination was the first step of bond cleavage. Isotope enrichment factors (εC and εCl) were derived from the transformation of γ-HCH (εC, from -4.0 ± 0.5 to -4.4 ± 0.6 ‰; εCl, from -2.9 ± 0.4 to -3.3 ± 0.4 ‰) and α-HCH (εC, from -2.4 ± 0.2 to -3.0 ± 0.4 ‰; εCl, from -1.4 ± 0.3 to -1.8 ± 0.2 ‰). During α-HCH transformation, no enantioselectivity was observed, and similar εc values were obtained for both enantiomers. The correlation of 13C and 37Cl fractionation (Λ = Δδ13C/Δδ37Cl ≈ εC/εCl) of γ-HCH (from 1.1 ± 0.3 to 1.2 ± 0.1) indicates similar bond cleavage during the reductive dichloroelimination by the three cultures, similar to α-HCH (1.7 ± 0.2 to 2.0 ± 0.3). The different isotope fractionation patterns during reductive dichloroelimination and dehydrochlorination indicates that dual-element stable isotope analysis can potentially be used to evaluate HCH transformation pathways at contaminated field sites.
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Affiliation(s)
- Yaqing Liu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Jia Liu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Haidian District, Beijing 100083, PR China
| | - Julian Renpenning
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Ivonne Nijenhuis
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Hans-Hermann Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
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Lian S, Nikolausz M, Nijenhuis I, da Rocha UN, Liu B, Corrêa FB, Saraiva JP, Richnow HH. Biotransformation of hexachlorocyclohexanes contaminated biomass for energetic utilization demonstrated in continuous anaerobic digestion system. JOURNAL OF HAZARDOUS MATERIALS 2020; 384:121448. [PMID: 31668499 DOI: 10.1016/j.jhazmat.2019.121448] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/19/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Lindane, the γ-hexachlorocyclohexane (HCH) isomer, was among the most used pesticides worldwide. Although it was banned in 2009, residues of Lindane and other HCH-isomers are still found with high concentrations in contaminated fields. For clean-up, phytoremediation combined with anaerobic digestion (AD) of contaminated biomass to produce biogas and fertilizer could be a promising strategy and was tested in two 15 L laboratory-scale continuous stirred tank reactors. During operation over one year by adding HCH isomers (γ, α and β) consecutively, no negative influence on conventional reactor parameters was observed. The γ- and α-HCH isomers were transformed to chlorobenzene and benzene, and transformation became faster along with time, while β-HCH was not removed. Genus Methanosaeta and order Clostridiales, showing significant enhancement on abundance with HCH addition, may be used as bioindicators for HCH dehalogenation in AD process. The potential for HCH degradation in AD system was restricted to axial Cl atoms of HCH and it showed slight enantioselective preference towards transformation of (+) α-HCH. Moreover, metabolite benzene was mineralized to CO2 and methane, deducing from tracer experiments with benzene-13C6. Overall, AD appears to be a feasible option for treatment of γ and α-HCHs contaminated biomass.
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Affiliation(s)
- Shujuan Lian
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Marcell Nikolausz
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Ivonne Nijenhuis
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Ulisses Nunes da Rocha
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Bin Liu
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Felipe Borim Corrêa
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - João Pedro Saraiva
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Hans Hermann Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
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8
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Liu Y, Bashir S, Stollberg R, Trabitzsch R, Weiß H, Paschke H, Nijenhuis I, Richnow HH. Compound Specific and Enantioselective Stable Isotope Analysis as Tools To Monitor Transformation of Hexachlorocyclohexane (HCH) in a Complex Aquifer System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:8909-8916. [PMID: 28673086 DOI: 10.1021/acs.est.6b05632] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Technical hexachlorocyclohexane (HCH) mixtures and Lindane (γ-HCH) have been produced in Bitterfeld-Wolfen, Germany, for about 30 years until 1982. In the vicinity of the former dump sites and production facilities, large plumes of HCHs persist within two aquifer systems. We studied the natural attenuation of HCH in these groundwater systems through a combination of enantiomeric and carbon isotope fractionation to characterize the degradation of α-HCH in the areas downstream of a former disposal and production site in Bitterfeld-Wolfen. The concentration and isotope composition of α-HCH from the Quaternary and Tertiary aquifers were analyzed. The carbon isotope compositions were compared to the source signal of waste deposits for the dumpsite and highly contaminated areas. The average value of δ13C at dumpsite was -29.7 ± 0.3 ‰ and -29.0 ± 0.1 ‰ for (-) and (+)α-HCH, respectively, while those for the β-, γ-, δ-HCH isomers were -29.0 ± 0.3 ‰, -29.5 ± 0.4 ‰, and -28.2 ± 0.2 ‰, respectively. In the plume, the enantiomer fraction shifted up to 0.35, from 0.50 at source area to 0.15 (well T1), and was found accompanied by a carbon isotope enrichment of 5 ‰ and 2.9 ‰ for (-) and (+)α-HCH, respectively. The established model for interpreting isotope and enantiomer fractionation patterns showed potential for analyzing the degradation process at a field site with a complex history with respect to contamination and fluctuating geochemical conditions.
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Affiliation(s)
- Yaqing Liu
- Department Of Isotope Biogeochemistry, Helmholtz Centre For Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
| | - Safdar Bashir
- Department Of Isotope Biogeochemistry, Helmholtz Centre For Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
| | - Reiner Stollberg
- Department Groundwater Remediation, Helmholtz Centre For Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
| | - Ralf Trabitzsch
- Department Groundwater Remediation, Helmholtz Centre For Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
| | - Holger Weiß
- Department Groundwater Remediation, Helmholtz Centre For Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
| | - Heidrun Paschke
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
| | - Ivonne Nijenhuis
- Department Of Isotope Biogeochemistry, Helmholtz Centre For Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
| | - Hans-Hermann Richnow
- Department Of Isotope Biogeochemistry, Helmholtz Centre For Environmental Research-UFZ , Permoserstraße 15, 04318 Leipzig, Germany
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9
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Gao XF, Nie J, Ouyang XK, Wang YG, Wu WJ. Enantioseparation and enantioselective behavior of trichlorfon enantiomers in sediments. Chirality 2017; 29:140-146. [DOI: 10.1002/chir.22686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 11/16/2016] [Accepted: 02/02/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Xiao-Feng Gao
- School of Food and Pharmacy; Zhejiang Ocean University; Zhoushan P. R China
| | - Jing Nie
- School of Food and Pharmacy; Zhejiang Ocean University; Zhoushan P. R China
| | - Xiao-Kun Ouyang
- School of Food and Pharmacy; Zhejiang Ocean University; Zhoushan P. R China
| | - Yang-Guang Wang
- School of Food and Pharmacy; Zhejiang Ocean University; Zhoushan P. R China
| | - Wei-Jian Wu
- School of Food and Pharmacy; Zhejiang Ocean University; Zhoushan P. R China
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McLachlan MS, Zou H, Gouin T. Using Benchmarking To Strengthen the Assessment of Persistence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4-11. [PMID: 27977157 DOI: 10.1021/acs.est.6b03786] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chemical persistence is a key property for assessing chemical risk and chemical hazard. Current methods for evaluating persistence are based on laboratory tests. The relationship between the laboratory based estimates and persistence in the environment is often unclear, in which case the current methods for evaluating persistence can be questioned. Chemical benchmarking opens new possibilities to measure persistence in the field. In this paper we explore how the benchmarking approach can be applied in both the laboratory and the field to deepen our understanding of chemical persistence in the environment and create a firmer scientific basis for laboratory to field extrapolation of persistence test results.
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Affiliation(s)
- Michael S McLachlan
- Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University , SE-106 91 Stockholm, Sweden
| | - Hongyan Zou
- Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University , SE-106 91 Stockholm, Sweden
| | - Todd Gouin
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire, U.K. , MK44 1LQ
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Liu X, Shen Z, Wang P, Liu C, Yao G, Zhou Z, Liu D. Enantioselective Characteristics and Montmorillonite-Mediated Removal Effects of α-Hexachlorocyclohexane in Laying Hens. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5695-5701. [PMID: 27163366 DOI: 10.1021/acs.est.6b01111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
α-Hexachlorocyclohexane (α-HCH) is a chiral organochlorine pesticide that is often ubiquitously detected in various environmental matrices and may be absorbed by the human body via food consumption, with serious detriments to human health. In this study, enantioselective degradation kinetics and residues of α-HCH in laying hens were investigated after a single dose of exposure to the pesticide, whereas enantioselectivity and residues of α-HCH in eggs, droppings, and various tissues were investigated after long-term exposure. Meanwhile, montmorillonite (MMT), a feed additive with high capacity of adsorption, was investigated for its ability to remove α-HCH from laying hens. Most non-brain tissues enantioselectively accumulated (-)-α-HCH, while (+)-α-HCH was preferentially accumulated in the brain. The enantiomer fractions (EFs) in most tissues gradually decreased, implying continuous depletion of (+)-α-HCH in laying hens. After 30 days of exposure and 31 days of elimination, the concentration of α-HCH in eggs and tissues of laying hens with MMT-containing feed was lower than that with MMT-free feed, indicating the removal effects of MMT for α-HCH in laying hens. The findings presented herein suggest that modified MMT may potentially be useful in reducing the enrichment of α-HCH in laying hens and eggs, thus lowering the risk of human intake of α-HCH.
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Affiliation(s)
- Xueke Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University , Beijing 100193, People's Republic of China
| | - Zhigang Shen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University , Beijing 100193, People's Republic of China
| | - Peng Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University , Beijing 100193, People's Republic of China
| | - Chang Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University , Beijing 100193, People's Republic of China
| | - Guojun Yao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University , Beijing 100193, People's Republic of China
| | - Zhiqiang Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University , Beijing 100193, People's Republic of China
| | - Donghui Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University , Beijing 100193, People's Republic of China
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12
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Chartrand M, Passeport E, Rose C, Lacrampe-Couloume G, Bidleman TF, Jantunen LM, Sherwood Lollar B. Compound specific isotope analysis of hexachlorocyclohexane isomers: a method for source fingerprinting and field investigation of in situ biodegradation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:505-14. [PMID: 26160416 DOI: 10.1002/rcm.7146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/07/2015] [Accepted: 01/08/2015] [Indexed: 05/06/2023]
Abstract
RATIONALE The manufacturing and uses of hexachlorocyclohexane (HCH) have resulted in a serious environmental challenge and legacy. This study highlights the ability of compound specific isotope analysis (CSIA) to distinguish among various HCH sources and to support the evaluation of the potential for in situ biodegradation in contaminated groundwater. METHODS Tests were conducted to verify the absence of significant isotope fractionation during HCH sample pre-concentration including dichloromethane extraction, solvent exchange into iso-octane, and H2SO4 clean-up, and analysis by gas chromatography/combustion-isotope ratio mass spectrometry (GC/C-IRMS). The method was then applied to four Technical Grade (TG) HCH mixtures procured from different sources and to groundwater samples from a contaminated site. RESULTS The pre-concentration method enabled determination of carbon isotope ratios (δ(13)C values) of HCH isomers with no significant isotopic fractionation. The TG-HCH mixtures had significantly different δ(13)C values. Moreover, for any given TG-HCH, all isomers had δ(13)C values within 1.1‰ of each other - a distinctly uniform fingerprint. At the HCH-contaminated field site, compared with source wells, downgradient wells showed significant (up to 5.1‰) enrichment in (13)C and the δ(13)C values of the HCH isomers were significantly different from each other. CONCLUSIONS A method was successfully developed for the CSIA of HCH isomers that showed potential for HCH source differentiation and identification of HCH in situ biodegradation. At the HCH-contaminated site, the observed preferential isotopic enrichment of certain isomers relative to others for a given source allows differentiation between biodegraded and non-biodegraded HCH.
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Affiliation(s)
- Michelle Chartrand
- Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, ON, M5S 3B1, Canada
| | - Elodie Passeport
- Department of Civil Engineering, University of Toronto, 35 Russell Street, Toronto, ON, M5S 1A4, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Carla Rose
- Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, ON, M5S 3B1, Canada
| | - Georges Lacrampe-Couloume
- Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, ON, M5S 3B1, Canada
| | - Terry F Bidleman
- Dept. of Chemistry, Umeå University, Linnaeus väg 6, SE-901 87, Umeå, Sweden
| | - Liisa M Jantunen
- Air Quality Processes Research Section, Environment Canada, 6248 Eighth Line, Egbert, ON, L0L1N0, Canada
| | - Barbara Sherwood Lollar
- Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, ON, M5S 3B1, Canada
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Bashir S, Fischer A, Nijenhuis I, Richnow HH. Enantioselective carbon stable isotope fractionation of hexachlorocyclohexane during aerobic biodegradation by Sphingobium spp. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:11432-11439. [PMID: 24007541 DOI: 10.1021/es402197s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Carbon isotope fractionation was investigated for the biotransformation of γ- and α- hexachlorocyclohexane (HCH) as well as enantiomers of α-HCH using two aerobic bacterial strains: Sphingobium indicum strain B90A and Sphingobium japonicum strain UT26. Carbon isotope enrichment factors (ε(c)) for γ-HCH (ε(c) = -1.5 ± 0.1 ‰ and -1.7 ± 0.2 ‰) and α-HCH (ε(c) = -1.0 ± 0.2 ‰ and -1.6 ± 0.3 ‰) were similar for both aerobic strains, but lower in comparison with previously reported values for anaerobic γ- and α-HCH degradation. Isotope fractionation of α-HCH enantiomers was higher for (+) α-HCH (ε(c) = -2.4 ± 0.8 ‰ and -3.3 ± 0.8 ‰) in comparison to (-) α-HCH (ε(c) = -0.7 ± 0.2 ‰ and -1.0 ± 0.6 ‰). The microbial fractionation between the α-HCH enantiomers was quantified by the Rayleigh equation and enantiomeric fractionation factors (ε(e)) for S. indicum strain B90A and S. japonicum strain UT26 were -42 ± 16% and -22 ± 6%, respectively. The extent and range of isomer and enantiomeric carbon isotope fractionation of HCHs with Sphingobium spp. suggests that aerobic biodegradation of HCHs can be monitored in situ by compound-specific stable isotope analysis (CSIA) and enantiomer-specific isotope analysis (ESIA). In addition, enantiomeric fractionation has the potential as a complementary approach to CSIA and ESIA for assessing the biodegradation of α-HCH at contaminated field sites.
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Affiliation(s)
- Safdar Bashir
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ , Permoserstraße 15, 04318, Leipzig, Germany
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Liu Y, Han P, Li XY, Shih K, Gu JD. Enantioselective degradation and unidirectional chiral inversion of 2-phenylbutyric acid, an intermediate from linear alkylbenzene, by Xanthobacter flavus PA1. JOURNAL OF HAZARDOUS MATERIALS 2011; 192:1633-1640. [PMID: 21794984 DOI: 10.1016/j.jhazmat.2011.06.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 06/10/2011] [Accepted: 06/29/2011] [Indexed: 05/31/2023]
Abstract
Microbial degradation of the chiral 2-phenylbutyric acid (2-PBA), a metabolite of surfactant linear alkylbenzene sulfonates (LAS), was investigated using both racemic and enantiomer-pure compounds together with quantitative stereoselective analyses. A pure culture of bacteria, identified as Xanthobacter flavus strain PA1 isolated from the mangrove sediment of Hong Kong Mai Po Nature Reserve, was able to utilize the racemic 2-PBA as well as the single enantiomers as the sole source of carbon and energy. In the presence of the racemic compounds, X. flavus PA1 degraded both (R) and (S) forms of enantiomers to completion in a sequential manner in which the (S) enantiomer disappeared much faster than the (R) enantiomer. When the single pure enantiomer was supplied as the sole substrate, a unidirectional chiral inversion involving (S) enantiomer to (R) enantiomer was evident. No major difference was observed in the degradation intermediates with either of the individual enantiomers when used as the growth substrate. Two major degradation intermediates were detected and identified as 3-hydroxy-2-phenylbutanoic acid and 4-methyl-3-phenyloxetan-2-one, using a combination of liquid chromatography-mass spectrometry (LC-MS), and (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy. The biochemical degradation pathway follows an initial oxidation of the alkyl side chain before aromatic ring cleavage. This study reveals new evidence for enantiomeric inversion catalyzed by pure culture of environmental bacteria and emphasizes the significant differences between the two enantiomers in their environmental fates.
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Affiliation(s)
- Yishan Liu
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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Badea SL, Vogt C, Gehre M, Fischer A, Danet AF, Richnow HH. Development of an enantiomer-specific stable carbon isotope analysis (ESIA) method for assessing the fate of α-hexachlorocyclo-hexane in the environment. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:1363-1372. [PMID: 21504001 DOI: 10.1002/rcm.4987] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
α-Hexachlorocyclohexane (α-HCH) is the only chiral isomer of the eight 1,2,3,4,5,6-HCHs and we have developed an enantiomer-specific stable carbon isotope analysis (ESIA) method for the evaluation of its fate in the environment. The carbon isotope ratios of the α-HCH enantiomers were determined for a commercially available α-HCH sample using a gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) system equipped with a chiral column. The GC-C-IRMS measurements revealed δ-values of -32.5 ± 0.8‰ and -32.3 ± 0.5‰ for (-) α-HCH and (+) α-HCH, respectively. The isotope ratio of bulk α-HCH was estimated to be -32.4 ± 0.6‰ which was in accordance with the δ-values obtained by GC-C-IRMS (-32.7 ± 0.2‰) and elemental analyzer-isotope ratio mass spectrometry (EA-IRMS) of the bulk α-HCH (-32.1 ± 0.1‰). The similarity of the isotope ratio measurements of bulk α-HCH by EA-IRMS and GC-C-IRMS indicates the accuracy of the chiral GC-C-IRMS method. The linearity of the α-HCH ESIA method shows that carbon isotope ratios can be obtained for a signal size above 100 mV. The ESIA measurements exhibited standard deviations (2σ) that were mostly < ± 0.5‰. In order to test the chiral GC-C-IRMS method, the isotope compositions of individual enantiomers in biodegradation experiments of α-HCH with Clostridium pasteurianum and samples from a contaminated field site were determined. The isotopic compositions of the α-HCH enantiomers show a range of enantiomeric and isotope patterns, suggesting that enantiomeric and isotope fractionation can serve as an indicator for biodegradation and source characterization of α-HCH in the environment.
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Affiliation(s)
- Silviu-Laurentiu Badea
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany
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Biochemistry of microbial degradation of hexachlorocyclohexane and prospects for bioremediation. Microbiol Mol Biol Rev 2010; 74:58-80. [PMID: 20197499 DOI: 10.1128/mmbr.00029-09] [Citation(s) in RCA: 235] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lindane, the gamma-isomer of hexachlorocyclohexane (HCH), is a potent insecticide. Purified lindane or unpurified mixtures of this and alpha-, beta-, and delta-isomers of HCH were widely used as commercial insecticides in the last half of the 20th century. Large dumps of unused HCH isomers now constitute a major hazard because of their long residence times in soil and high nontarget toxicities. The major pathway for the aerobic degradation of HCH isomers in soil is the Lin pathway, and variants of this pathway will degrade all four of the HCH isomers although only slowly. Sequence differences in the primary LinA and LinB enzymes in the pathway play a key role in determining their ability to degrade the different isomers. LinA is a dehydrochlorinase, but little is known of its biochemistry. LinB is a hydrolytic dechlorinase that has been heterologously expressed and crystallized, and there is some understanding of the sequence-structure-function relationships underlying its substrate specificity and kinetics, although there are also some significant anomalies. The kinetics of some LinB variants are reported to be slow even for their preferred isomers. It is important to develop a better understanding of the biochemistries of the LinA and LinB variants and to use that knowledge to build better variants, because field trials of some bioremediation strategies based on the Lin pathway have yielded promising results but would not yet achieve economic levels of remediation.
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Ma Y, Xu C, Wen Y, Liu W. Enantioselective separation and degradation of the herbicide dichlorprop methyl in sediment. Chirality 2009; 21:480-3. [DOI: 10.1002/chir.20624] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Elliott DW, Lien HL, Zhang WX. Zerovalent iron nanoparticles for treatment of ground water contaminated by hexachlorocyclohexanes. JOURNAL OF ENVIRONMENTAL QUALITY 2008; 37:2192-2201. [PMID: 18948472 DOI: 10.2134/jeq2007.0545] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ground water and aquifer samples from a site contaminated by hexachlorocyclohexanes (HCHs; C(6)H(6)Cl(6)) were exposed to nanoscale iron particles to evaluate the technology as a potential remediation method. The summed concentration of the HCH isomers in ground water was approximately 5.16 micromol L(-1) (1500 microg L(-1)). Batch experiments with 2.2 to 27.0 g L(-1) iron nanoparticles showed that more than 95% of the HCHs were removed from solution within 48 h. Using a pseudo first-order kinetics model, the HCH isomers were removed in accordance with the trend gamma congruent with alpha > beta > delta. This seems to be correlated with the orientation (axial vs. equatorial) of the chlorine atoms lost in the dihaloelimination steps. Although the reactivity of the HCH isomers has been investigated in the classical organic chemistry literature, the present study was the first in the environmental remediation arena. The rate of removal is directly correlated to the number of axial chlorines. The observed rate constant varied from 0.04 to 0.65 h(-1), and the rate constant normalized to the iron surface area concentration ranged from 5.4 x 10(-4) to 8.8 x 10(-4) L m(-2) h(-1). Post-test extractions of the reactor contents detected little HCH remaining in solution or on the iron surfaces, reinforcing the contention that reaction rather than sorption was the operative mechanism for the HCH removal. Together with previously published work on a wide variety of chlorinated organic solvents, this work further demonstrates the potential of zerovalent iron nanoparticles for treatment and remediation of persistent organic pollutants.
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Chapter 10 Organic contaminant speciation and bioavailability in the terrestrial environment. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s0166-2481(07)32010-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Zhao X, Quan X, Chen S, Zhao HM, Liu Y. Photocatalytic remediation of gamma-hexachlorocyclohexane contaminated soils using TiO2 and montmorillonite composite photocatalyst. J Environ Sci (China) 2007; 19:358-61. [PMID: 17918601 DOI: 10.1016/s1001-0742(07)60059-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading gamma-hexachlorocyclohexane (gamma-HCH) in soils. After being spiked with gamma-HCH, soil samples loaded with the composite photocatalysts were exposed to UV-light irradiation. The results indicated that the photocatalytic activities of the composite photocatalysts varied with the content of TiO2 in the order of 10% < 70% < 50% < 30%. Moreover, the photocatalytic activity of the composite photocatalysts with TiO2 content 30% was higher than that of the pure P25 with the same mass of TiO2. The strong adsorption capacity of the composite photocatalysts and quantum size effect may contribute to its increased photocatalytic activities. In addition, effect of dosage of composite photocatalysts and soil pH on gamma-HCH photodegradation was investigated. Pentachlorocyclohexene, trichlorocyclohexene, and dichlorobenzene were detected as photodegradation intermediates, which were gradually degraded with the photodegradation evolution.
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Affiliation(s)
- Xu Zhao
- Department of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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Phillips TM, Seech AG, Lee H, Trevors JT. Biodegradation of hexachlorocyclohexane (HCH) by microorganisms. Biodegradation 2005; 16:363-92. [PMID: 15865341 DOI: 10.1007/s10532-004-2413-6] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The organochlorine pesticide Lindane is the gamma-isomer of hexachlorocyclohexane (HCH). Technical grade Lindane contains a mixture of HCH isomers which include not only gamma-HCH, but also large amounts of predominantly alpha-, beta- and delta-HCH. The physical properties and persistence of each isomer differ because of the different chlorine atom orientations on each molecule (axial or equatorial). However, all four isomers are considered toxic and recalcitrant worldwide pollutants. Biodegradation of HCH has been studied in soil, slurry and culture media but very little information exists on in situ bioremediation of the different isomers including Lindane itself, at full scale. Several soil microorganisms capable of degrading, and utilizing HCH as a carbon source, have been reported. In selected bacterial strains, the genes encoding the enzymes involved in the initial degradation of Lindane have been cloned, sequenced, expressed and the gene products characterized. HCH is biodegradable under both oxic and anoxic conditions, although mineralization is generally observed only in oxic systems. As is found for most organic compounds, HCH degradation in soil occurs at moderate temperatures and at near neutral pH. HCH biodegradation in soil has been reported at both low and high (saturated) moisture contents. Soil texture and organic matter appear to influence degradation presumably by sorption mechanisms and impact on moisture retention, bacterial growth and pH. Most studies report on the biodegradation of relatively low (< 500 mg/kg) concentrations of HCH in soil. Information on the effects of inorganic nutrients, organic carbon sources or other soil amendments is scattered and inconclusive. More in-depth assessments of amendment effects and evaluation of bioremediation protocols, on a large scale, using soil with high HCH concentrations, are needed.
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Affiliation(s)
- Theresa M Phillips
- Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
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