Use of dual element isotope analysis and microcosm studies to determine the origin and potential anaerobic biodegradation of dichloromethane in two multi-contaminated aquifers
Blázquez Pallí, Natàlia (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Shouakar Stash, Orfan (University of Waterloo. Department of Earth and Environmental Sciences)
Palau Capdevila, Jordi (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)
Trueba-Santiso, Alba (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Varias, Joan (Litoclean, S.L.)
Bosch, Marçal (Litoclean, S.L.)
Soler, Albert (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)
Vicent i Huguet, Teresa (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Marco Urrea, Ernest (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Rosell, Mònica (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)

Data:	2019
Resum:	Many aquifers around the world are impacted by toxic chlorinated methanes derived from industrial processes due to accidental spills. Frequently, these contaminants co-occur with chlorinated ethenes and/or chlorinated benzenes in groundwater, forming complex mixtures that become very difficult to remediate. In this study, a multi-method approach was used to provide lines of evidence of natural attenuation processes and potential setbacks in the implementation of bioremediation strategies in multi-contaminated aquifers. First, this study determined i) the carbon and chlorine isotopic compositions (δ¹³C, δ³⁷Cl) of several commercial pure phase chlorinated compounds, and ii) the chlorine isotopic fractionation (εCl = −5. 2 ± 0. 6‰) and the dual CCl isotope correlation (ΛC/Cl = 5. 9 ± 0. 3) during dichloromethane (DCM) degradation by a Dehalobacterium-containing culture. Such data provide valuable information for practitioners to support the interpretation of stable isotope analyses derived from polluted sites. Second, the bioremediation potential of two industrial sites contaminated with a mixture of organic pollutants (mainly DCM, chloroform (CF), trichloroethene (TCE), and mono-chlorobenzene (MCB)) was evaluated. Hydrochemistry, dual (CCl) isotope analyses, laboratory microcosms, and microbiological data were used to investigate the origin, fate and biodegradation potential of chlorinated methanes. At Site 1, δ¹³C and δ³⁷Cl compositions from field samples were consistent with laboratory microcosms, which showed complete degradation of CF, DCM and TCE, while MCB remained. Identification of Dehalobacter sp. in CF-enriched microcosms further supported the biodegradation capability of the aquifer to remediate chlorinated methanes. At Site 2, hydrochemistry and δ¹³C and δ³⁷Cl compositions from field samples suggested little DCM, CF and TCE transformation; however, laboratory microcosms evidenced that their degradation was severely inhibited, probably by co-contamination. A dual CCl isotopic assessment using results from this study and reference values from the literature allowed to determine the extent of degradation and elucidated the origin of chlorinated methanes.
Ajuts:	Ministerio de Economía y Competitividad CGL2017-87216-C4-1-R Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-14 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1733 Ministerio de Economía y Competitividad CTM2016-75587-C2-1-R Agència de Gestió d'Ajuts Universitaris i de Recerca 2015-DI-064 Ministerio de Economía y Competitividad BES-2014-070817 Ministerio de Economía y Competitividad RYC-2012-11920
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Matèria:	2D-CSIA ; Dehalobacter ; Dehalobacterium ; Dichloromethane ; Chloroform ; Organohalide respiration ; Natural attenuation
Publicat a:	Science of the total environment, Vol. 696 (Dec. 2019) , art. 134066, ISSN 1879-1026

DOI: 10.1016/j.scitotenv.2019.134066

Preprint 46 p, 1.4 MB

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