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Kuznetsova OV. Current trends and challenges in the analysis of marine environmental contaminants by isotope ratio mass spectrometry. Anal Bioanal Chem 2024; 416:71-85. [PMID: 37979060 DOI: 10.1007/s00216-023-05029-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 10/26/2023] [Accepted: 10/30/2023] [Indexed: 11/19/2023]
Abstract
An increasing number of organic and inorganic pollutants are being detected in the marine environment, posing a severe threat to the ecosystem and human health, even in trace concentrations. Isotope ratio mass spectrometry (IRMS) is one of the critical methods for determining the origin and fate of environmental pollutants and characterising their transformation processes. It has been used for a relatively long time for ecological monitoring of some well-studied industrial hydrocarbons at contaminated sites. However, the method still faces many analytical challenges. This review provides a comprehensive overview of recent technical advances concerning IRMS analysis of various contaminants and discusses typical pitfalls encountered in marine environment analysis. Particular attention is given to the study of sampling techniques and sample preparation for examination, often the keys to successful research given the complexity of marine matrices and the diverse and numerous nature of contaminants. Prospects for developing IRMS to monitor pollution sources and pollutant transformation in the marine environment are outlined.
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Affiliation(s)
- Olga V Kuznetsova
- Vernadsky Institute of Geochemistry and Analytical Chemistry, Kosygin St. 19, 119991, Moscow, Russian Federation.
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Liu X, Wu L, Kümmel S, Gehre M, Richnow HH. Determination of Stable Hydrogen Isotopic Composition and Isotope Enrichment Factor at Low Hydrogen Concentration. Anal Chem 2023; 95:16272-16278. [PMID: 37878670 PMCID: PMC10637740 DOI: 10.1021/acs.analchem.3c03214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/30/2023] [Accepted: 10/09/2023] [Indexed: 10/27/2023]
Abstract
Determination of stable hydrogen isotopic compositions (δ2H) is currently challenged to achieve a high detection limit for reaching the linear range where δ2H values are independent of concentration. Therefore, it is difficult to assess precise δ2H values for calculating the hydrogen isotope enrichment factor (εH) and for field application where the concentrations of contaminants are relatively low. In this study, a data treatment approach was developed to obtain accurate δ2H values below the linear range. The core concept was to use a logarithmic function to fit the δ2H values below the linear range and then adjust the δ2H values below the linear range into the linear range by using the fitted logarithmic equation. Moreover, the adjusted δ2H values were calibrated by using laboratory reference materials, e.g., n-alkanes. Tris(2-chloroethyl) phosphate (TCEP) and hexachlorocyclohexane (HCH) isomers were selected as examples of complex heteroatom-bearing compounds to develop the data treatment approach. This data treatment approach was then tested using δ2H values from a TCEP transformation experiment with OH radicals. Comparable δ2H values and εH between the low-concentration experiment and the reference experiment were obtained using the developed approach. Therefore, the developed data treatment approach enables a possibility of determining the hydrogen isotopic compositions of organic components in low concentrations. It is especially valuable for determining organic contaminants in environmental samples, which are usually present in low concentrations.
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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
- Ecometrix
Incorporated, 6800 Campobello
Road, Mississauga, ON L5N 2L8, Canada
| | - 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
| | - Hans Hermann Richnow
- Department
of Isotope Biogeochemistry, Helmholtz Centre
for Environmental Research-UFZ,Permoserstraße 15, 04318 Leipzig, Germany
- Isodetect
GmbH, Deutscher Platz
5b, 04103 Leipzig, Germany
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Blessing M, Baran N. A review on environmental isotope analysis of aquatic micropollutants: Recent advances, pitfalls and perspectives. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Gilevska T, Sullivan Ojeda A, Kümmel S, Gehre M, Seger E, West K, Morgan SA, Mack EE, Sherwood Lollar B. Multi-element isotopic evidence for monochlorobenzene and benzene degradation under anaerobic conditions in contaminated sediments. WATER RESEARCH 2021; 207:117809. [PMID: 34741903 DOI: 10.1016/j.watres.2021.117809] [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: 03/24/2021] [Revised: 08/10/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Industrial chemicals are frequently detected in sediments due to a legacy of chemical spills. Globally, site remedies for groundwater and sediment decontamination include natural attenuation by in situ abiotic and biotic processes. Compound-specific isotope analysis (CSIA) is a diagnostic tool to identify, quantify, and characterize degradation processes in situ, and in some cases can differentiate between abiotic degradation and biodegradation. This study reports high-resolution carbon, chlorine, and hydrogen stable isotope profiles for monochlorobenzene (MCB), and carbon and hydrogen stable isotope profiles for benzene, coupled with measurements of pore water concentrations in contaminated sediments. Multi-element isotopic analysis of δ13C and δ37Cl for MCB were used to generate dual-isotope plots, which for 2 locations at the study site resulted in ΛC/Cl(130) values of 1.42 ± 0.19 and ΛC/Cl(131) values of 1.70 ± 0.15, consistent with theoretical calculations for carbon-chlorine bond cleavage (ΛT = 1.80 ± 0.31) via microbial reductive dechlorination. For benzene, significant δ2H (122‰) and δ13C (6‰) depletion trends, followed by enrichment trends in δ13C (1.6‰) in the upper part of the sediment, were observed at the same location, indicating not only production of benzene due to biodegradation of MCB, but subsequent biotransformation of benzene itself to nontoxic end-products. Degradation rate constants calculated independently using chlorine isotopic data and carbon isotopic data, respectively, agreed within uncertainty thus providing multiple lines of evidence for in situ contaminant degradation via reductive dechlorination and providing the foundation for a novel approach to determine site-specific in situ rate estimates essential for the prediction of remediation outcomes and timelines.
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Affiliation(s)
- Tetyana Gilevska
- Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada; CNRS/EOST, ITES UMR 7063, Earth and Environment Institute of Strasbourg (ITES), University of Strasbourg, Strasbourg, 67084, France
| | - Ann Sullivan Ojeda
- Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada; Department of Geosciences, Auburn University, Auburn, AL 36849, United States
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research, UFZ, Leipzig, 04318, Germany
| | - Matthias Gehre
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research, UFZ, Leipzig, 04318, Germany
| | - Edward Seger
- The Chemours Company, Wilmington, DE 19810, United States
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Ojeda AS, Zheng J, Phillips E, Sherwood Lollar B. Implications of regression bias for multi-element isotope analysis for environmental remediation. Talanta 2021; 226:122113. [PMID: 33676669 DOI: 10.1016/j.talanta.2021.122113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 11/24/2022]
Abstract
Measuring changes in the stable isotope ratios of multiple elements (e.g. Δδ13C, Δδ37Cl, and Δδ2H) during the (bio)transformation of environmental contaminants has provided new insights into reaction mechanisms and tools to optimize remediation efforts. Dual-isotope analysis, wherein changes in one isotopic system are plotted against another (to derive an interpretational parameter expressed as Λ), is a key tool in multi-element isotopic assessment. To date, most dual-isotope analyses use ordinary linear regression (OLR) for the calculation, which can be subject to regression attenuation and thus an inherent artifact that depresses slope values, expressed as Λ. Here, a series of Monte Carlo simulations were constructed to represent common data conditions and variations within dual-isotope data to test the degree of bias when deriving Λ using OLR compared to an alternative regression technique, the York method. The degree of bias was quantified compared to the modeled or "true" Λ value. For all simulations, the York method provided the least bias in slope estimates (<1%) over all data conditions tested. In contrast, OLR produced unbiased estimates only under a limited set of conditions, which was validated through a mathematical model proof. Both the mathematical model and simulations show that bias of at least 5% in OLR occurs when the extent of enrichment in the x-variable (XM) is equal to or less than ≈15 times the 1σ precision in the isotope measurement (σX), for both Cl/C and C/H plots. The results give practitioners tools to evaluate whether bias is present in data and to estimate the extent to which this negatively impacts the interpretations and predictions of remediation potential for new and previously published datasets. This study demonstrates that integration of such robust statistical tools is essential for dual-isotope interpretations widely used in contaminant hydrogeology but relevant to other disciplines including environmental chemistry and ecology.
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Affiliation(s)
| | - Jingyi Zheng
- Auburn University, Department of Mathematics and Statistics, Auburn, AL, 36849, USA
| | - Elizabeth Phillips
- University of Toronto, Department of Earth Sciences, Toronto, ON, M5S 3B1, Canada
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