Remediation of chlorinated ethenes in fractured sandstone by natural and enhanced biotic and abiotic processes: A crushed rock microcosm study

Yu, Rong; Andrachek, Richard G.; Lehmicke, Leo G.; Freedman, David L.

doi:10.1016/j.scitotenv.2018.01.064

Cited by 38 publications

(51 citation statements)

References 18 publications

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“…The optimum redox potential for a complete reductive dechlorination is less than -100 mV (Elsner and Hofstetter, 2011) but, as indicated in Table 1, no negative redox potentials were measured in the monitored wells, although higher reducing microenvironments in the aquifer cannot be discarded. As oxygen, nitrate, and sulphate are consumed, the redox potential is expected to fall, but reduction of these electron acceptors can be hampered by the lack of electron donor in groundwater (Yu et al, 2018). According to this hypothesis, the addition of easily fermentable organic substrates (lactate and the mixture of ethanol plus methanol) to the microcosms enhanced the dechlorination of PCE with respect to the control by shortening the lag phase of PCE dechlorination and overcoming the "DCE stall", which permitted the full dechlorination to ethene ( Figure 3A and S3A).…”

Section: Discussionmentioning

confidence: 99%

Multi-method assessment of the intrinsic biodegradation potential of an aquifer contaminated with chlorinated ethenes at an industrial area in Barcelona (Spain)

Blázquez-Pallí

Rosell

Varias³

et al. 2019

Environmental Pollution

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

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Section: Discussionmentioning

confidence: 99%

Multi-method assessment of the intrinsic biodegradation potential of an aquifer contaminated with chlorinated ethenes at an industrial area in Barcelona (Spain)

Blázquez-Pallí

Rosell

Varias³

et al. 2019

Environmental Pollution

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“…While the importance of abiotic degradation processes to plume‐scale attenuation has been increasingly considered, a more reliable quantitative assessment of these transformation processes will allow for improved predictive tools for long‐term plume management. For example, Yu et al () measured abiotic transformation rates equivalent to half‐life values of about 20 years for TCE and 23 years for cis ‐dichloroethene, which they note may be sufficient to support an MNA remedy for some site settings. Improved quantification of abiotic degradation processes will increase confidence for MNA and passive remedies, especially where abiotic degradation of CVOCs by reactive minerals is the dominant mechanism for transformation.…”

Section: Applying Abiotic Pathways For Site Restorationmentioning

confidence: 99%

“…Chlorinated volatile organic compound (CVOC) degradation can occur through biotic or abiotic mechanisms. This diagram, from Yu et al , shows how trichloroethene (TCE) is degraded through microbial action (top) or through abiotic reactions with iron sulfide minerals (bottom). Reactive iron minerals can be intentionally formed in situ by stimulating sulfate reducing bacteria.…”

Section: Introductionmentioning

confidence: 99%

New Tools for Assessing Reactive Mineral‐Mediated Abiotic Contaminant Transformation

Horst¹,

Divine²,

Tilton³

et al. 2019

Groundwater Monitoring Rem

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“…This bioremediation approach is commonly referred to as biostimulation or ERD, which stands for enhanced reductive dechlorination (Adrian and Löffler, 2016;Leeson et al, 2004). To date, many studies have focused on laboratory methodologies to assess and characterize the intrinsic bioremediation potential of CEs-polluted sites by OHRB (Buchner et al, 2015;Courbet et al, 2011;Ebert et al, 2010;Kuder et al, 2013;Lee et al, 2016;Lu et al, 2009;Matteucci et al, 2015;Nijenhuis et al, 2007;Slater et al, 2001;Tarnawski et al, 2016;Yu et al, 2018), but few have reported results after applying ERD and CSIA at the field scale (Herrero et al, 2019;Hirschorn et al, 2007;Song et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Integrative isotopic and molecular approach for the diagnosis and implementation of an efficient in-situ enhanced biological reductive dechlorination of chlorinated ethenes

Blázquez-Pallí

Rosell

Varias³

et al. 2019

Water Research

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

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Remediation of chlorinated ethenes in fractured sandstone by natural and enhanced biotic and abiotic processes: A crushed rock microcosm study

Cited by 38 publications

References 18 publications

Multi-method assessment of the intrinsic biodegradation potential of an aquifer contaminated with chlorinated ethenes at an industrial area in Barcelona (Spain)

Multi-method assessment of the intrinsic biodegradation potential of an aquifer contaminated with chlorinated ethenes at an industrial area in Barcelona (Spain)

New Tools for Assessing Reactive Mineral‐Mediated Abiotic Contaminant Transformation

Integrative isotopic and molecular approach for the diagnosis and implementation of an efficient in-situ enhanced biological reductive dechlorination of chlorinated ethenes

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