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Filippini M, Leoncini C, Luchetti L, Emiliani R, Fabbrizi E, Gargini A. Detecting vinyl chloride by phytoscreening in the shallow critical zone at sites with potential human exposure. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 319:115776. [PMID: 35982574 DOI: 10.1016/j.jenvman.2022.115776] [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: 05/11/2022] [Revised: 07/01/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Chlorinated ethene (CE) contaminants are widespread in groundwater, and the occurrence of vinyl chloride (VC), among others, is a well-known issue due to its mobility, persistence, and carcinogenicity. Human exposure to VC may occur through inhalation after soil vapor intrusion into buildings at sites with shallow underground contamination. Soil vapor intrusion risk is traditionally assessed through indoor air and sub-slab sampling (direct evidence) or soil gas and groundwater surveys (indirect evidence). Phytoscreening (sampling and analysis of tree trunk matrices) was proven as a cost-effective alternative technique to indirectly detect shallow underground contamination by higher chlorinated ethenes and subsequent vapor intrusion risk. However, the technique has appeared barely capable to screen for the lower chlorinated VC, likely due to its fugacity and aerobic bio-degradability, with only one literature record to date showing successful detection in trees. We applied phytoscreening at two sites with severe CE contamination nearby residential buildings caused by illegal dumping of chlorinated pitches from petrochemical productions. The two sites show variable amounts of VC in the shallow groundwater (1e2 to 1e4 μg/L), posing potential sanitary risk issues. Former soil gas surveys did not detect VC in the vadose zone. At both sites, we sampled trunk micro-cores and trunk gas from poplar trees close to contaminated piezometers in different seasons. VC was detected in several instances, disproving the shared literature assumption of the inefficacy of phytoscreening towards this compound. Factors influencing the detectability of VC and other CEs in trees were analyzed through linear regressions. Two different conceptual models were proposed to explain the effective uptake of VC by trees at the two sites, i.e., direct uptake of contaminated groundwater at the first site and uptake of VC from an anoxic vadose zone at the second site. In planta reductive dechlorination of CEs is not expected based on current literature knowledge. Thus, the detection of VC in trunks would indicate its occurrence in the shallow underground, suggesting higher screening effectiveness of phytoscreening compared to soil gas; this has implications for indirect vapor intrusion risk assessment.
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Affiliation(s)
- Maria Filippini
- Department of Biological, Geological and Environmental Sciences, Alma Mater Studiorum University of Bologna, Via Zamboni 67, 40126, Bologna, Italy.
| | - Carlotta Leoncini
- Department of Biological, Geological and Environmental Sciences, Alma Mater Studiorum University of Bologna, Via Zamboni 67, 40126, Bologna, Italy
| | - Lucina Luchetti
- Senior Geologist Expert PNRR- ARTA (Regional Authority for the Protection of Environment -Abruzzo), District of Chieti, Via San Michele 32, 66100, Chieti, Italy
| | - Renata Emiliani
- ARPAE (Authority for the Prevention Environment and Energy -Emilia Romagna), District of Ravenna, Via Alberoni 17/19, 48121, Ravenna, Italy
| | - Emanuela Fabbrizi
- ARPAE (Authority for the Prevention Environment and Energy -Emilia Romagna), District of Bologna, Via Rocchi 19, 40138, Bologna, Italy
| | - Alessandro Gargini
- Department of Biological, Geological and Environmental Sciences, Alma Mater Studiorum University of Bologna, Via Zamboni 67, 40126, Bologna, Italy
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Ciampi P, Esposito C, Bartsch E, Alesi EJ, Petrangeli Papini M. 3D dynamic model empowering the knowledge of the decontamination mechanisms and controlling the complex remediation strategy of a contaminated industrial site. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 793:148649. [PMID: 34328981 DOI: 10.1016/j.scitotenv.2021.148649] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/04/2021] [Accepted: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Knowledge of the geology and hydrogeology of the polluted site emblematize a key requirement for environmental remediation, through assembling and synthesizing findings from various sources of physical evidence. In an increasingly virtual era, digital and geo-referenced metadata may serve as tools for collecting, merging, matching, and understanding multi-source information. The main goal of this paper is to emphasize the significance of a 3D hydrogeochemical model to the portrayal and the understanding of contamination dynamics and decontamination mechanisms at a highly contaminated industrial site. Some remediation measures are active on-site, due to the evidence-based presence of chlorinated solvents in groundwater. These are attributable to a slow-release source of pollutants in the saturated zone associated with very low permeability sediments. Therefore, in this research, a new technique for the remediation of secondary sources of dense non-aqueous phase liquid (DNAPL) contamination was investigated for the first time on a full-scale application. The combination of groundwater circulation wells (IEG-GCW®) and a continuous electron donor production device was set up to boost in situ bioremediation (ISB). A multi-phase approach was followed handling and releasing data during various remediation stages, from site characterization via pilot testing to full-scale remediation, thus allowing users to monitor, analyze, and manipulate information in 3D space-time. Multi-source and multi-temporal scenarios reveal the impact of ongoing hydraulic dynamics and depict the decontamination mechanisms in response to the interventions implemented over time, by quantifying the overall performance of the adopted strategies in terms of removal of secondary sources of pollution still active at the site.
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Affiliation(s)
- Paolo Ciampi
- Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Carlo Esposito
- Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Ernst Bartsch
- IEG Technologie GmbH, Hohlbachweg 2, D-73344 Gruibingen, Baden-Württemberg, Germany.
| | - Eduard J Alesi
- IEG Technologie GmbH, Hohlbachweg 2, D-73344 Gruibingen, Baden-Württemberg, Germany.
| | - Marco Petrangeli Papini
- Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
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Evaluation of MNA in A Chlorinated Solvents-Contaminated Aquifer Using Reactive Transport Modeling Coupled with Isotopic Fractionation Analysis. WATER 2021. [DOI: 10.3390/w13212945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Groundwater contamination by chlorinated hydrocarbons is a worldwide problem that poses important challenges in remediation processes. In Italy, the Legislative Decree 152/06 defines the water quality limits to be obtained during the cleanup process. In situ bioremediation techniques are becoming increasingly important due to their affordability and, under the right conditions, because they can be more effective than conventional methodologies. In the initial feasibility study phase, the numerical modeling supports the reliability of each technique. Two different codes, BIOCHLOR and PHREEQC were discussed and compared assuming different field conditions. Isotopic Fractionation-Reactive Transport Models were then developed in one synthetic and one simple field case. From the results, the two codes were in agreement and also able to demonstrate the Monitored Natural Attenuation processes occurring at the dismissed site located in Italy. Finally, the PHREEQC model was used to forecast the remediation time frame by MNA, hypothesizing a complete source cleanup: a remediation time frame of about 10–11 years was achieved by means of natural attenuation processes.
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Castellani F, Manzoli L, Martellucci CA, Flacco ME, Astolfi ML, Fabiani L, Mastrantonio R, Avino P, Protano C, Vitali M. Levels of Polychlorinated Dibenzo-p-Dioxins/Furans and Polychlorinated Biphenyls in Free-Range Hen Eggs in Central Italy and Estimated Human Dietary Exposure. J Food Prot 2021; 84:1455-1462. [PMID: 33852724 DOI: 10.4315/jfp-21-126] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 04/13/2021] [Indexed: 12/17/2022]
Abstract
ABSTRACT The aim of the present study was to evaluate the contamination levels of some classes of persistent organic pollutants in free-range hen eggs and to estimate the related human dietary exposure in a site of national interest, characterized by a serious state of environmental pollution in the Bussi sul Tirino area in central Italy. For these purposes, 17 samples of free-range hen eggs collected in home-producing farms located in the site of national interest territory were analyzed for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), 12 dioxin-like polychlorinated biphenyls (dl-PCBs), and 6 non-dioxin-like PCBs (ndl-PCBs). Dietary exposure was assessed assuming a standard consumption of eggs per week. The concentration of ∑PCDD/Fs plus dl-PCBs ranged from 0.463 to 8.028 pg toxic equivalent g-1 fat, whereas the mean contamination level of the ∑ndl-PCBs ranged from 0.234 to 7.741 ng toxic equivalent g-1 fat. PCDD/Fs and PCBs contamination levels were lower than maximum values established by the Commission Regulation (European Union) 1259/2011, except for one sample. The estimated weekly intake, calculated to evaluate the contribution in terms of the monitored pollutants of the locally produced eggs to the diet, was lower than the tolerable weekly intake established by the European Food Safety Authority. HIGHLIGHTS
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Affiliation(s)
- F Castellani
- Department of Public Health and Infectious Diseases, University of Ferrara, Via Fossato di Mortara 64B, 44121 Ferrara (FE), Italy
| | - L Manzoli
- Department of Medical Sciences, University of Ferrara, Via Fossato di Mortara 64B, 44121 Ferrara (FE), Italy
| | - C Acuti Martellucci
- Department of Medical Sciences, University of Ferrara, Via Fossato di Mortara 64B, 44121 Ferrara (FE), Italy
| | - M E Flacco
- Department of Medical Sciences, University of Ferrara, Via Fossato di Mortara 64B, 44121 Ferrara (FE), Italy
| | - M L Astolfi
- Department of Chemistry, University of Rome La Sapienza, P.le Aldo Moro, 5, 00185 Rome, Italy
| | - L Fabiani
- Department of Life, Health & Environmental Sciences, University of L'Aquila, P.le Salvatore Tommasi 1, 67100 Coppito, L'Aquila, Italy
| | - R Mastrantonio
- Department of Life, Health & Environmental Sciences, University of L'Aquila, P.le Salvatore Tommasi 1, 67100 Coppito, L'Aquila, Italy
| | - P Avino
- Department of Agricultural, Environmental and Food Sciences (DiAAA), University of Molise, via De Sanctis, 86100 Campobasso, Italy
| | - C Protano
- Department of Public Health and Infectious Diseases, University of Ferrara, Via Fossato di Mortara 64B, 44121 Ferrara (FE), Italy
| | - M Vitali
- Department of Public Health and Infectious Diseases, University of Ferrara, Via Fossato di Mortara 64B, 44121 Ferrara (FE), Italy
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Vitali M, Castellani F, Fragassi G, Mascitelli A, Martellucci C, Diletti G, Scamosci E, Astolfi ML, Fabiani L, Mastrantonio R, Protano C, Spica VR, Manzoli L. Environmental status of an Italian site highly polluted by illegal dumping of industrial wastes: The situation 15 years after the judicial intervention. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:144100. [PMID: 33360460 DOI: 10.1016/j.scitotenv.2020.144100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/03/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
In 2008 the Italian government classified the Bussi sul Tirino area (Central Italy) as Site of National Interest destined to remediation which, unfortunately, has not yet begun. The decision followed >20 years of illegal dumping of industrial wastes, lasting from 1984 to 2005, that generated the biggest illegal toxic waste disposal site in Europe. The contamination profile of the site was mainly characterized by PCDD/Fs, PCBs, PAHs, chlorinated solvents, Hg, and Pb. Due to the health concern of the population and local authorities, an extensive monitoring and biomonitoring campaign was carried out in 2017-2018, checking the site-specific pollutants in local food (free-range hens' eggs, milk from grazing sheep and goats, wild edible mushrooms, and drinking water), environmental (air and freshwaters) and biological (human urine) matrices. A total of 314 samples were processed, obtaining 3217 analytical data that were compared with regulatory limits, when available, and values reported by international literature. The sum PCDD/Fs and DL-PCBs ranged from 0.24 to 3.6 pg TEQ g-1 fat, and from 0.46 to 8.3 pg TEQ g-1 fat, respectively in milk in eggs, in line with the maximum levels established by CE Regulations except for an egg sample. As regards PAHs, all our results were lower than the literature data, as well as for Hg and Pb. Outdoor air showed levels of chlorinated solvents ranging from <LOD to 36 μg m-3, and freshwaters from 0.21 to 2.8 μg L-1. All drinking water samples resulted compliant with the maximum levels established by the current EU directive. Despite the severe pollution of the illegal dumping site and the remediation not yet carried out, the local environment and the population living in Bussi and surroundings seem not to be affected by significant exposure to the toxics characterizing the landfill.
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Affiliation(s)
- Matteo Vitali
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, P.le Aldo Moro, 5, 00185 Rome, Italy.
| | - Federica Castellani
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, P.le Aldo Moro, 5, 00185 Rome, Italy; Department of Ecological and Biological Sciences, Tuscia University, Largo dell'Università snc, 01100 Viterbo, Italy.
| | - Giorgia Fragassi
- Regional Healthcare Agency of Abruzzo, Via Attilio Monti 9, 65127 Pescara, PE, Italy
| | - Alfonso Mascitelli
- Regional Healthcare Agency of Abruzzo, Via Attilio Monti 9, 65127 Pescara, PE, Italy
| | - Cecilia Martellucci
- Department of Biomedical Sciences and Public Health, University of the Marche Region, Via Tronto 10/a, 60020 Torrette di Ancona, AN, Italy
| | - Gianfranco Diletti
- Istituto Zooprofilattico Sperimentale of Abruzzo and Molise "Giuseppe Caporale", via Campo Boario, 64100 Teramo, TE, Italy.
| | - Emanuela Scamosci
- Environmental Protection Regional Agency of Abruzzo, via Marconi 49, 65126 Pescara, PE, Italy.
| | - Maria Luisa Astolfi
- Department of Chemistry, University of Rome La Sapienza, P.le Aldo Moro, 5, 00185 Rome, Italy.
| | - Leila Fabiani
- Department of Life, Health & Environmental Sciences, University of L'Aquila, P.le Salvatore Tommasi 1, 67100 Coppito, L'Aquila, Italy.
| | - Riccardo Mastrantonio
- Department of Life, Health & Environmental Sciences, University of L'Aquila, P.le Salvatore Tommasi 1, 67100 Coppito, L'Aquila, Italy.
| | - Carmela Protano
- Department of Public Health and Infectious Diseases, University of Rome La Sapienza, P.le Aldo Moro, 5, 00185 Rome, Italy.
| | - Vincenzo Romano Spica
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro De Bosis 6, 00135 Rome, Italy.
| | - Lamberto Manzoli
- Department of Medical Sciences, University of Ferrara, Via Fossato di Mortara 64B, 44121 Ferrara, FE, Italy.
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6
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Jin B, Zhang J, Xu W, Rolle M, Liu J, Zhang G. Simultaneous determination of stable chlorine and bromine isotopic ratios for bromochlorinated trihalomethanes using GC-qMS. CHEMOSPHERE 2021; 264:128529. [PMID: 33038736 DOI: 10.1016/j.chemosphere.2020.128529] [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: 05/13/2020] [Revised: 09/05/2020] [Accepted: 10/01/2020] [Indexed: 06/11/2023]
Abstract
Bromochlorinated compounds are organic contaminants originating from different natural and anthropic sources and increasingly found in different environmental compartments. This work presents an online approach for compound specific stable isotope analysis of chlorine and bromine isotope ratios for bromochlorinated trihalomethanes using gas chromatography coupled to quadrupole mass spectrometry (GC-qMS). An evaluation scheme was developed to simultaneously determine stable chlorine and bromine isotope ratios based on the mass spectral data of two target compounds: dibromochloromethane and dichlorobromomethane. The analytical technique was optimized by assessing the impact of different instrumental parameters, including dwell time, split ratios, and ionization energy. Successively, static headspace samples containing the two target compounds at aqueous concentrations ranging from 0.1 mg/L to 5 mg/L were analyzed in order to test the precision and reproducibility of the proposed approach. The results showed a good precision under the optimized instrumental conditions, with relative standard deviations ranging between 0.05% and 0.5% for chlorine and bromine isotope analysis. Finally, the method was tested in a source identification problem in which the simultaneous determination of chlorine and bromine stable isotope ratios allowed the clear distinction of dibromochloromethane from three different manufacturers.
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Affiliation(s)
- Biao Jin
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; Guangdong Key Laboratory of Environmental Protection and Resources Utilization, China; University of Chinese Academy of Sciences, Beijing, 10069, China.
| | - Jiyun Zhang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 10069, China
| | - Wenli Xu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 10069, China
| | - Massimo Rolle
- DTU Environment, Department of Environmental Engineering, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Jinzhong Liu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Gan Zhang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
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Li L. Toxicity evaluation and by-products identification of triclosan ozonation and chlorination. CHEMOSPHERE 2021; 263:128223. [PMID: 33297179 DOI: 10.1016/j.chemosphere.2020.128223] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 05/05/2023]
Abstract
Triclosan (TCS) has attracted increasing concern due to its ubiquitous occurrence in aquatic environments as well as its potential adverse effects on human health. This study investigated the toxicity and transformation characteristics of triclosan ozonation and chlorination. The results showed that two hydroxylated by-products were formed via nucleophilic substitution during ozonation, while three chlorinated compounds were generated via electrophilic substitution during chlorination. The toxicity results demonstrated that the parent compound, triclosan, exhibited mild genotoxicity and anti-estrogenic activity. The chlorination of triclosan resulted in a 30-fold increase in anti-estrogenic activity owing to the generation of toxic polychlorinated transformation by-products. In addition, the chlorination by-products were found to be genotoxic like the parent compound. Fortunately, in contrast to chlorination, ozonation could mitigate the genotoxicity and anti-estrogenic activity of triclosan-containing water.
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Affiliation(s)
- Liping Li
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China; Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, PR China.
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8
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Gilevska T, Sullivan Ojeda A, Renpenning J, Kümmel S, Gehre M, Nijenhuis I, Sherwood Lollar B. Requirements for Chromium Reactors for Use in the Determination of H Isotopes in Compound-Specific Stable Isotope Analysis of Chlorinated Compounds. Anal Chem 2020; 92:2383-2387. [PMID: 31898453 DOI: 10.1021/acs.analchem.9b04737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is a strong need for careful quality control in hydrogen compound-specific stable isotope analysis (CSIA) of halogenated compounds. This arises in part due to the lack of universal design of the chromium (Cr) reactors. In this study, factors that optimize the critical performance parameter, linearity, for the Cr reduction method for hydrogen isotope analysis were identified and evaluated. These include the effects of short and long vertically mounted reactors and temperature profiles on trapping of Cl to ensure accurate and precise hydrogen isotope measurements. This paper demonstrates the critical parameters that need consideration to optimize any Cr reactor applications to ensure the accuracy of δ2H analysis for organic compounds and to enhance intercomparability for both international standards and reference materials run by continuous flow versus an elemental analyzer.
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Affiliation(s)
- Tetyana Gilevska
- Department of Earth Sciences , University of Toronto , Toronto , Ontario M5S 3B1 , Canada
| | - Ann Sullivan Ojeda
- Department of Earth Sciences , University of Toronto , Toronto , Ontario M5S 3B1 , Canada
| | - Julian Renpenning
- Department of Isotope Biogeochemistry , Helmholtz Centre for Environmental Research - UFZ , Permoserstrasse 15 , 04318 Leipzig , Germany
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry , Helmholtz Centre for Environmental Research - UFZ , Permoserstrasse 15 , 04318 Leipzig , Germany
| | - Matthias Gehre
- Department of Isotope Biogeochemistry , 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
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Blázquez-Pallí N, Rosell M, Varias J, Bosch M, Soler A, Vicent T, Marco-Urrea E. Multi-method assessment of the intrinsic biodegradation potential of an aquifer contaminated with chlorinated ethenes at an industrial area in Barcelona (Spain). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 244:165-173. [PMID: 30326388 DOI: 10.1016/j.envpol.2018.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/02/2018] [Accepted: 10/02/2018] [Indexed: 06/08/2023]
Abstract
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.
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Affiliation(s)
- Natàlia Blázquez-Pallí
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), c/ de les Sitges s/n, 08193, Cerdanyola del Vallès, Spain; Litoclean, S.L., c/ Numància 36, 08029, Barcelona, Spain
| | - Mònica Rosell
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Geomicrobiologia, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028, Barcelona, Spain
| | - Joan Varias
- Litoclean, S.L., c/ Numància 36, 08029, Barcelona, Spain
| | - Marçal Bosch
- Litoclean, S.L., c/ Numància 36, 08029, Barcelona, Spain
| | - Albert Soler
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Geomicrobiologia, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), c/ Martí Franquès s/n, 08028, Barcelona, Spain
| | - Teresa Vicent
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), c/ de les Sitges s/n, 08193, Cerdanyola del Vallès, Spain
| | - Ernest Marco-Urrea
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), c/ de les Sitges s/n, 08193, Cerdanyola del Vallès, Spain.
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