Stratification of chlorinated ethenes natural attenuation in an alluvial aquifer assessed by hydrochemical and biomolecular tools

Němeček, Jan; Dolinová, Iva; Macháčková, Jiřina; Špánek, Roman; Ševců, Alena; Lederer, Tomáš; Černík, Miroslav

doi:10.1016/j.chemosphere.2017.06.100

Cited by 32 publications

(26 citation statements)

References 35 publications

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“…In fact, molasse addition increased the relative abundance of fermentative microorganisms. Bacterial fermentation was likely driven by fermentative members of the phylum Firmicutes, as previously observed in other CE-contaminated sites [100][101][102]. Members of the genera Desulfosporosinus, able to ferment lactate [31], and Dehalobacter significantly contributed to this increase.…”

Section: Impact Of the Biostimulation Treatment On The Aquifer Microbial Communitysupporting

confidence: 55%

Effectiveness of Permeable Reactive Bio-Barriers for Bioremediation of an Organohalide-Polluted Aquifer by Natural-Occurring Microbial Community

Bertolini

Zecchin

Beretta

et al. 2021

Water

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In this study, a bioremediation approach was evaluated for the decontamination of an aquifer affected by the release of organohalides by an industrial landfill. After preliminary physicochemical and microbiological characterization of the landfill groundwater, the stimulation of natural organohalide respiration by the addition of a reducing substrate (i.e., molasse) was tested both at microcosm and at field scales, by the placement of an anaerobic permeable reactive bio-barrier. Illumina sequencing of cDNA 16S rRNA gene revealed that organohalide-respiring bacteria of genera Geobacter, Sulfurospirillum, Dehalococcoides, Clostridium and Shewanella were present within the aquifer microbial community, along with fermentative Firmicutes and Parvarchaeota. Microcosm experiments confirmed the presence of an active natural attenuation, which was boosted by the addition of the reducing substrate. Field tests showed that the bio-barrier decreased the concentration of chloroethenes at a rate of 23.74 kg d−1. Monitoring of organohalide respiration biomarkers by qPCR and Illumina sequencing revealed that native microbial populations were involved in the dechlorination process, although their specific role still needs to be clarified. The accumulation of lower-chloroethenes suggested the need of future improvement of the present approach by supporting bacterial vinyl-chloride oxidation, to achieve a complete degradation of chloroethenes.

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Section: Impact Of the Biostimulation Treatment On The Aquifer Microbial Communitysupporting

confidence: 55%

Effectiveness of Permeable Reactive Bio-Barriers for Bioremediation of an Organohalide-Polluted Aquifer by Natural-Occurring Microbial Community

Bertolini

Zecchin

Beretta

et al. 2021

Water

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“…These macroand microheterogeneities and abilities of aerobic ethenotrophs to sustain low levels of oxygen are reasons for their occurrence in anaerobic aquifers containing anaerobic dechlorinators. Co-occurrence of anaerobic dechlorinators and VC assimilating bacteria was revealed also in groundwater samples from other sites [20,29], in discrete aquifer soil samples [19] as well as in surface riverbed sediment samples [47] where the TOC content in soil was found to be the critical parameter determining the dominant degradation pathway [48].…”

Section: Hydrochemical Conditions For Aerobic Oxidationmentioning

confidence: 75%

“…All qPCR assays were performed on a LightCycler ® 480 (Roche, Switzerland), using the same reaction conditions described in our previous study [29]. qPCR mixtures with a total volume of 10 µL were prepared using LightCycler ® 480 SYBR Green I Master (Roche, Switzerland), 4 pmol of each primer (Generi Biotech, Czech Republic) and 1 µL of template DNA.…”

Section: Dna Extraction and Real-time Quantitative Pcrmentioning

confidence: 99%

Hydrochemical Conditions for Aerobic/Anaerobic Biodegradation of Chlorinated Ethenes—A Multi-Site Assessment

Němeček

Marková

Špánek

et al. 2020

Water

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A stall of cis-1,2-DCE and vinyl chloride (VC) is frequently observed during bioremediation of groundwater chloroethenes via reductive dechlorination. These chloroethenes may be oxidised by aerobic methanotrophs or ethenotrophs co-metabolically and/or metabolically. We assessed the potential for such oxidation at 12 sites (49 groundwater samples) using hydrochemical and molecular biological tools. Both ethenotroph (etnC and etnE) and methanotroph (mmoX and pmoA) functional genes were identified in 90% of samples, while reductive dehalogenase functional genes (vcrA and bvcA) were identified in 82%. All functional genes were simultaneously detected in 78% of samples, in actively biostimulated sites in 88% of samples. Correlation analysis revealed that cis-1,2-DCE concentration was positively correlated with vcrA, etnC and etnE, while VC concentration was correlated with etnC, etnE, vcrA and bvcA. However, feature selection based on random forest classification indicated a significant relationship for the vcrA in relation to cis-1,2-DCE, and vcrA, bvcA and etnE for VC and no prove of relationship between cis-1,2-DCE or VC and the methanotroph functional genes. Analysis of hydrochemical parameters indicated that aerobic oxidation of chloroethenes by ethenotrophs may take place under a range of redox conditions of aquifers and coincide with high ethene and VC concentrations.

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“…This corresponded with elevated levels of total dissolved iron (Fe(II)). Gallionella is commonly found in the groundwater of CE-contaminated sites [47,51] and has been described as capable of dechlorinating TCE under sulphate-reducing conditions [49]. While iron-reducing Geobacter were already abundant in well 14/04 and in the upper layer of CMT 1, their abundance increased even further after nZVI-AC application (Table 2; Fig.…”

Section: Effect Of Nzvi-ac Applicationmentioning

confidence: 99%

In situ pilot application of nZVI embedded in activated carbon for remediation of chlorinated ethene-contaminated groundwater: effect on microbial communities

et al. 2020

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Background Nanoscale zero-valent iron (nZVI) is commonly used for remediation of groundwater contaminated by chlorinated ethenes (CEs); however, its long-term reactivity and subsurface transport are limited. A novel nZVI–AC material, consisting of colloidal activated carbon (AC) with embedded nZVI clusters, was developed with the aim of overcoming the limitations of nZVI alone. Results Application of a limited amount of nZVI–AC to an oxic, nitrate-rich, highly permeable quaternary aquifer triggered time-limited transformation of CEs, with noticeable involvement of reductive dechlorination. Reductive dechlorination of CEs was dominantly abiotic, as an increase in the concentration of vinyl chloride (VC) and ethene did not coincide with an increase in the abundance of reductive biomarkers for complete dechlorination of CEs (Dehalococcoides, Dehalogenimonas, VC reductase genes vcrA and bvcA). Application of nZVI–AC under unfavourable hydrochemical conditions resulted in no dramatic change in the microbial community, the reducing effect resulting in temporal proliferation of nitrate and iron reducers only. At a later stage, generation of reduced iron induced an increase in iron-oxidizing bacteria. High concentrations and a continuous mass influx of competing electron acceptors (nitrate and dissolved oxygen) created unfavourable conditions for sulphate-reducers and organohalide-respiring bacteria, though it allowed the survival of aerobic microorganisms of the genera Pseudomonas, Polaromonas and Rhodoferax, known for their ability to assimilate VC or cis-1,2-dichloroethene. A potential for aerobic oxidative degradation of CE metabolites was also indicated by detection of the ethenotroph functional gene etnE. Conclusions This pilot study, based on the application of nZVI–AC, failed to provide a sustainable effect on CE contamination; however, it provided valuable insights into induced hydrogeochemical and microbial processes that could help in designing full-scale applications.

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Stratification of chlorinated ethenes natural attenuation in an alluvial aquifer assessed by hydrochemical and biomolecular tools

Cited by 32 publications

References 35 publications

Effectiveness of Permeable Reactive Bio-Barriers for Bioremediation of an Organohalide-Polluted Aquifer by Natural-Occurring Microbial Community

Effectiveness of Permeable Reactive Bio-Barriers for Bioremediation of an Organohalide-Polluted Aquifer by Natural-Occurring Microbial Community

Hydrochemical Conditions for Aerobic/Anaerobic Biodegradation of Chlorinated Ethenes—A Multi-Site Assessment

In situ pilot application of nZVI embedded in activated carbon for remediation of chlorinated ethene-contaminated groundwater: effect on microbial communities

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