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Künzli M, Dürr-Auster T, Bracher C, Zhao Y, Bachelder J, Emmanuel F, Wiggenhauser M. 67Zn and 111Cd labelled green manure to determine the fate and dynamics of zinc and cadmium in soil-fertilizer-crop systems. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2024; 60:286-308. [PMID: 38488879 DOI: 10.1080/10256016.2024.2324966] [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: 06/20/2023] [Accepted: 02/22/2024] [Indexed: 03/17/2024]
Abstract
Isotope source tracing enables to accurately determine the fate of nutrients that are applied with fertilizers to soils. While this approach is well established for major nutrients such as nitrogen, it is not yet established for trace metals. Here, we aimed to determine the fate of the micronutrient zinc (Zn) and the contaminant cadmium (Cd) that were applied with an organic fertilizer to a soil-wheat system. A pot study was conducted in which wheat was grown on an alkaline soil. The soils received green manure and/or soluble Zn fertilizer and were compared with non-fertilized control treatments (n = 4 experimental replicates). The green manure was labelled with the stable isotopes 67Zn and 111Cd. For an efficient sample throughput, a method was provided and validated to determine enriched stable isotope ratios (67Zn:66Zn and 111Cd:110Cd) and the Zn and Cd concentrations in one analytical run. To this end, single collector ICP-MS analyses and stable isotope mass balances calculations were combined. Applying this method revealed that the addition of green manure increased neither Zn nor Cd concentrations in wheat grains due to biomass dilution effects. Isotope source tracing showed that the largest fraction of these metals in the wheat shoots derived from the soil in all treatments (Zn 87-99 %, Cd 94-98 %). Moreover, the addition of green manure increased the transfer of Zn and Cd from soil to wheat by a factor 1.9 for both elements. This increased transfer was likely related to a nitrogen fertilization effect that increased root and shoot biomass and thereby the soil exploration of the wheat. This study demonstrated how the fate and dynamics of multiple trace metals can be efficiently determined in soil-fertilizer-crop systems using isotope source tracing.
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Affiliation(s)
- Manja Künzli
- Institute of Agricultural Sciences, ETH, Zurich, Switzerland
| | | | | | - Yang Zhao
- Institute of Agricultural Sciences, ETH, Zurich, Switzerland
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Bejing, People's Republic of China
| | - Jill Bachelder
- Institute of Agricultural Sciences, ETH, Zurich, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH, Zurich, Switzerland
- Department of Water Resources and Drinking Water, Eawag, Dubendorf, Switzerland
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Shao F, Li K, Ouyang D, Zhou J, Luo Y, Zhang H. Sources apportionments of heavy metal(loid)s in the farmland soils close to industrial parks: Integrated application of positive matrix factorization (PMF) and cadmium isotopic fractionation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 924:171598. [PMID: 38461995 DOI: 10.1016/j.scitotenv.2024.171598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 03/12/2024]
Abstract
Understanding the source identification and distribution of heavy metal(loid)s in soil is essential for risk management. The sources of heavy metal(loid)s in farmland soil, especially in areas with rapid economic development, were complicated and need to be explored urgently. This study combined geographic information system (GIS) mapping, positive matrix factorization (PMF) model and cadmium (Cd) isotope fingerprinting methods to identify heavy metal(loid) sources in a typical town in the economically developed Yangtze River Delta region of China. Cd, As, Cu, Zn, Pb, Ni and Co in different samples were detected. The results showed that Cd was the most severely contaminated element, with an exceedance rate of 78.0 %. GIS mapping results indicated that the hotspot area was located in the northeastern area with prolonged operational histories of electroplating and non-ferrous metal smelting industries. The PMF model analysis also identified emissions from smelting and electroplating enterprises as the main sources of Cd in the soil, counted for 49.28 %, followed by traffic (25.66 %) and agricultural (25.06 %) sources. Through further isotopic analysis, it was found that in soil samples near the industrial park, the contribution of electroplating and non-ferrous metal smelting enterprises to cadmium pollution was significantly higher than other regions. The integrated use of various methodologies allows for precise analysis of sources and input pathways, offering valuable insights for future pollution control and soil remediation endeavors.
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Affiliation(s)
- Fanglei Shao
- Zhejiang Provincial Key Laboratory of Soil Contamination Bioremediation, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China; Sino-Spain Joint Laboratory for Agricultural Environment Emerging Contaminants of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Kainan Li
- Zhejiang Provincial Key Laboratory of Soil Contamination Bioremediation, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China; Sino-Spain Joint Laboratory for Agricultural Environment Emerging Contaminants of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Da Ouyang
- Zhejiang Provincial Key Laboratory of Soil Contamination Bioremediation, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China; Sino-Spain Joint Laboratory for Agricultural Environment Emerging Contaminants of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Jiawen Zhou
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yating Luo
- Zhejiang Provincial Key Laboratory of Soil Contamination Bioremediation, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China; Sino-Spain Joint Laboratory for Agricultural Environment Emerging Contaminants of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China.
| | - Haibo Zhang
- Zhejiang Provincial Key Laboratory of Soil Contamination Bioremediation, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China; Sino-Spain Joint Laboratory for Agricultural Environment Emerging Contaminants of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China.
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Bracher C, Frossard E, Bigalke M, Imseng M, Mayer J, Wiggenhauser M. Tracing the fate of phosphorus fertilizer derived cadmium in soil-fertilizer-wheat systems using enriched stable isotope labeling. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 287:117314. [PMID: 34004476 DOI: 10.1016/j.envpol.2021.117314] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 06/12/2023]
Abstract
Applying mineral phosphorus (P) fertilizers introduces a considerable input of the toxic heavy metal cadmium (Cd) into arable soils. This study investigates the fate of P fertilizer derived Cd (Cddff) in soil-wheat systems using a novel combination of enriched stable Cd isotope mass balances, sequential extractions, and Bayesian isotope mixing models. We applied an enriched 111Cd labeled mineral P fertilizer to arable soils from two long-term field trials with distinct soil properties (a strongly acidic pH and a neutral pH) and distinct past mineral P fertilizer application rates. We then cultivated wheat in a pot trial on these two soils. In the neutral soil, Cd concentrations in the soil and the wheat increased with increasing past mineral P fertilizer application rates. This was not the case in the strongly acidic soil. Less than 2.3% of freshly applied Cddff was taken up by the whole wheat plant. Most of the Cddff remained in the soil and was predominantly (>95% of freshly applied Cddff) partitioned into the easily mobilizable acetic acid soluble fraction (F1) and the potentially mobile reducible fraction (F2). Soil pH was the determining factor for the partitioning of Cddff into F1, as revealed through a recovery of about 40% of freshly applied Cddff in F1 in the neutral pH soil compared with about 60% in the strongly acidic soil. Isotope mixing models showed that F1 was the predominant source of Cd for wheat on both soils and that it contributed to over 80% of the Cd that was taken up by wheat. By tracing the fate of Cddff in entire soil-plant systems using different isotope source tracing approaches, we show that the majority of Cddff remains mobilizable and is potentially plant available in the subsequent crop cycle.
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Affiliation(s)
- Christoph Bracher
- Institute of Geography, University of Bern, Hallerstrasse 12, 3012 Bern, Switzerland
| | - Emmanuel Frossard
- Institute of Agricultural Sciences, ETH Zurich, Eschikon 33, 8315 Lindau, Switzerland
| | - Moritz Bigalke
- Institute of Geography, University of Bern, Hallerstrasse 12, 3012 Bern, Switzerland
| | - Martin Imseng
- Institute of Geography, University of Bern, Hallerstrasse 12, 3012 Bern, Switzerland
| | - Jochen Mayer
- Agroscope, Reckenholzstrasse 191, 8046 Zurich, Switzerland
| | - Matthias Wiggenhauser
- Institute of Agricultural Sciences, ETH Zurich, Eschikon 33, 8315 Lindau, Switzerland.
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Wiggenhauser M, Aucour AM, Telouk P, Blommaert H, Sarret G. Changes of Cadmium Storage Forms and Isotope Ratios in Rice During Grain Filling. FRONTIERS IN PLANT SCIENCE 2021; 12:645150. [PMID: 33995443 PMCID: PMC8116553 DOI: 10.3389/fpls.2021.645150] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/08/2021] [Indexed: 05/10/2023]
Abstract
Rice poses a major source of the toxic contaminant cadmium (Cd) for humans. Here, we elucidated the role of Cd storage forms (i.e., the chemical Cd speciation) on the dynamics of Cd within rice. In a pot trial, we grew rice on a Cd-contaminated soil in upland conditions and sampled roots and shoots parts at flowering and maturity. Cd concentrations, isotope ratios, Cd speciation (X-ray absorption spectroscopy), and micronutrient concentrations were analyzed. During grain filling, Cd and preferentially light Cd isotopes were strongly retained in roots where the Cd storage form did not change (Cd bound to thiols, Cd-S = 100%). In the same period, no net change of Cd mass occurred in roots and shoots, and the shoots became enriched in heavy isotopes (Δ114/110Cd maturity-flowering = 0.14 ± 0.04‰). These results are consistent with a sequestration of Cd in root vacuoles that includes strong binding of Cd to thiol containing ligands that favor light isotopes, with a small fraction of Cd strongly enriched in heavy isotopes being transferred to shoots during grain filling. The Cd speciation in the shoots changed from predominantly Cd-S (72%) to Cd bound to O ligands (Cd-O, 80%) during grain filling. Cd-O may represent Cd binding to organic acids in vacuoles and/or binding to cell walls in the apoplast. Despite this change of ligands, which was attributed to plant senescence, Cd was largely immobile in the shoots since only 0.77% of Cd in the shoots were transferred into the grains. Thus, both storage forms (Cd-S and Cd-O) contributed to the retention of Cd in the straw. Cd was mainly bound to S in nodes I and grains (Cd-S > 84%), and these organs were strongly enriched in heavy isotopes compared to straw (Δ114/110Cd grains/nodes- straw = 0.66-0.72‰) and flag leaves (Δ114/110Cd grains/nodes-flag leaves = 0.49-0.52‰). Hence, xylem to phloem transfer in the node favors heavy isotopes, and the Cd-S form may persist during the transfer of Cd from node to grain. This study highlights the importance of Cd storage forms during its journey to grain and potentially into the food chain.
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Affiliation(s)
- Matthias Wiggenhauser
- Institute of Agricultural Sciences, Department of Environmental Systems Science, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
- ISTerre, Université Grenoble Alpes, Université Savoie Mont Blanc, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux, Grenoble, France
| | - Anne-Marie Aucour
- Laboratoire de Geologie de Lyon, Ecole Normale Supérieure de Lyon, Université Lyon 1, Université de Lyon, Centre National de la Recherche Scientifique, Lyon, France
| | - Philippe Telouk
- Laboratoire de Geologie de Lyon, Ecole Normale Supérieure de Lyon, Université Lyon 1, Université de Lyon, Centre National de la Recherche Scientifique, Lyon, France
| | - Hester Blommaert
- ISTerre, Université Grenoble Alpes, Université Savoie Mont Blanc, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux, Grenoble, France
| | - Géraldine Sarret
- ISTerre, Université Grenoble Alpes, Université Savoie Mont Blanc, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux, Grenoble, France
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Zhong Q, Zhou Y, Tsang DCW, Liu J, Yang X, Yin M, Wu S, Wang J, Xiao T, Zhang Z. Cadmium isotopes as tracers in environmental studies: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 736:139585. [PMID: 32497890 DOI: 10.1016/j.scitotenv.2020.139585] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Cadmium isotopic compositions in non-contaminated systems and anthropogenic sources of Cd generally have different isotopic signatures. Cadmium isotopes, as a novel tracer, can be useful for fingerprinting the anthropogenic Cd sources, providing a promising source tracing technique in environmental studies. This review presents: (i) analytical techniques for Cd isotopic composition; (ii) isotopic signatures of Cd derived from anthropogenic activities; (iii) isotopic compositions of Cd in the industrial-impacted environmental samples; (iv) cadmium isotopic fractionation induced by geochemical process. Finally, the perspectives of using Cd isotopic compositions in environmental studies are also briefly discussed.
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Affiliation(s)
- Qiaohui Zhong
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510405, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuchen Zhou
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Juan Liu
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Xiao Yang
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Meiling Yin
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Shijun Wu
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510405, China
| | - Jin Wang
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, Guangzhou 510006, China.
| | - Tangfu Xiao
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Zhaofeng Zhang
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510405, China
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Barraza F, Moore RET, Rehkämper M, Schreck E, Lefeuvre G, Kreissig K, Coles BJ, Maurice L. Cadmium isotope fractionation in the soil – cacao systems of Ecuador: a pilot field study. RSC Adv 2019; 9:34011-34022. [PMID: 35528875 PMCID: PMC9073709 DOI: 10.1039/c9ra05516a] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/14/2019] [Indexed: 12/22/2022] Open
Abstract
The often high Cd concentrations of cacao beans are a serious concern for producers in Latin America due to the implementation of stricter Cd limits for cocoa products by the European Union in 2019. This is the first investigation to employ coupled Cd isotope and concentration measurements to study soil – cacao systems. Analyses were carried out for 29 samples of soils, soil amendments and cacao tree organs from organic farms in Ecuador that harvest three distinct cacao cultivars. The majority of soils from 0–80 cm depth have very similar δ114/110Cd of about −0.1‰ to 0‰. Two 0–5 cm topsoils, however, have high Cd concentrations coupled with heavy Cd isotope compositions of δ114/110Cd ≈ 0.2%, possibly indicating Cd additions from the tree litter used as organic fertilizer. Whilst cacao leaves, pods and beans are ubiquitously enriched in Cd relative to soils there are distinct Cd isotope signatures. The leaves and pods are isotopically heavier than the soils, with similar Δ114/110Cdleaf–soil values of 0.22 ± 0.07‰ to 0.41 ± 0.09‰. In contrast, the data reveal differences in Δ114/110Cdbean–leaf that may be linked to distinct cacao cultivars. In detail, Δ114/110Cdbean–leaf values of −0.34‰ to −0.40‰ were obtained for Nacional cacao from two farms, whilst CCN-51 hybrid cacao from a third farm showed no fractionation within error (−0.08 ± 0.13‰). As such, further work to investigate whether Cd isotopes are indeed useful for tracing sources of Cd enrichments in soils and to inform genetic efforts to reduce the Cd burden of cocoa is indicated. Cd isotope composition in cacao seems to be cultivar-specific whereas Cd in soil is probably due to tree litter recycling.![]()
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Affiliation(s)
- Fiorella Barraza
- Géosciences Environnement Toulouse (GET)
- Observatoire Midi-Pyrénées
- CNRS
- IRD
- Université de Toulouse
| | - Rebekah E. T. Moore
- Department of Earth Science & Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - Mark Rehkämper
- Department of Earth Science & Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - Eva Schreck
- Géosciences Environnement Toulouse (GET)
- Observatoire Midi-Pyrénées
- CNRS
- IRD
- Université de Toulouse
| | - Grégoire Lefeuvre
- Géosciences Environnement Toulouse (GET)
- Observatoire Midi-Pyrénées
- CNRS
- IRD
- Université de Toulouse
| | - Katharina Kreissig
- Department of Earth Science & Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - Barry J. Coles
- Department of Earth Science & Engineering
- Imperial College London
- London SW7 2AZ
- UK
| | - Laurence Maurice
- Géosciences Environnement Toulouse (GET)
- Observatoire Midi-Pyrénées
- CNRS
- IRD
- Université de Toulouse
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Imseng M, Wiggenhauser M, Keller A, Müller M, Rehkämper M, Murphy K, Kreissig K, Frossard E, Wilcke W, Bigalke M. Fate of Cd in Agricultural Soils: A Stable Isotope Approach to Anthropogenic Impact, Soil Formation, and Soil-Plant Cycling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1919-1928. [PMID: 29308892 DOI: 10.1021/acs.est.7b05439] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The application of mineral phosphate (P) fertilizers leads to an unintended Cd input into agricultural systems, which might affect soil fertility and quality of crops. The Cd fluxes at three arable sites in Switzerland were determined by a detailed analysis of all inputs (atmospheric deposition, mineral P fertilizers, manure, and weathering) and outputs (seepage water, wheat and barley harvest) during one hydrological year. The most important inputs were mineral P fertilizers (0.49 to 0.57 g Cd ha-1 yr-1) and manure (0.20 to 0.91 g Cd ha-1 yr-1). Mass balances revealed net Cd losses for cultivation of wheat (-0.01 to -0.49 g Cd ha-1 yr-1) but net accumulations for that of barley (+0.18 to +0.71 g Cd ha-1 yr-1). To trace Cd sources and redistribution processes in the soils, we used natural variations in the Cd stable isotope compositions. Cadmium in seepage water (δ114/110Cd = 0.39 to 0.79‰) and plant harvest (0.27 to 0.94‰) was isotopically heavier than in soil (-0.21 to 0.14‰). Consequently, parent material weathering shifted bulk soil isotope compositions to lighter signals following a Rayleigh fractionation process (ε ≈ 0.16). Furthermore, soil-plant cycling extracted isotopically heavy Cd from the subsoil and moved it to the topsoil. These long-term processes and not anthropogenic inputs determined the Cd distribution in our soils.
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Affiliation(s)
- Martin Imseng
- Institute of Geography, University of Bern , Hallerstrasse 12, CH-3012 Bern, Switzerland
| | - Matthias Wiggenhauser
- Institute of Agricultural Sciences, ETH Zurich , Eschikon 33, CH-8315 Lindau, Switzerland
| | - Armin Keller
- Swiss Soil Monitoring Network (NABO), Agroscope , Reckenholzstrasse 191, CH-8046 Zürich, Switzerland
| | - Michael Müller
- Swiss Soil Monitoring Network (NABO), Agroscope , Reckenholzstrasse 191, CH-8046 Zürich, Switzerland
| | - Mark Rehkämper
- Department of Earth Science & Engineering, Imperial College London , SW7 2AZ London, U.K
| | - Katy Murphy
- Department of Earth Science & Engineering, Imperial College London , SW7 2AZ London, U.K
| | - Katharina Kreissig
- Department of Earth Science & Engineering, Imperial College London , SW7 2AZ London, U.K
| | - Emmanuel Frossard
- Institute of Agricultural Sciences, ETH Zurich , Eschikon 33, CH-8315 Lindau, Switzerland
| | - Wolfgang Wilcke
- Institute of Geography and Geoecology, Karlsruhe Institute of Technology (KIT) , Reinhard-Baumeister-Platz 1, 76131 Karlsruhe, Germany
| | - Moritz Bigalke
- Institute of Geography, University of Bern , Hallerstrasse 12, CH-3012 Bern, Switzerland
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Murphy K, Rehkämper M, Kreissig K, Coles B, van de Flierdt T. Improvements in Cd stable isotope analysis achieved through use of liquid-liquid extraction to remove organic residues from Cd separates obtained by extraction chromatography. JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY 2016; 31:319-327. [PMID: 27284213 PMCID: PMC4869401 DOI: 10.1039/c5ja00115c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 08/07/2015] [Indexed: 05/15/2023]
Abstract
Organic compounds released from resins that are commonly employed for trace element separations are known to have a detrimental impact on the quality of isotopic analyses by MC-ICP-MS. A recent study highlighted that such effects can be particularly problematic for Cd stable isotope measurements (M. Gault-Ringold and C. H. Stirling, J. Anal. At. Spectrom., 2012, 27, 449-459). In this case, the final stage of sample purification commonly applies extraction chromatography with Eichrom TRU resin, which employs particles coated with octylphenyl-N,N-di-isobutyl carbamoylphosphine oxide (CMPO) dissolved in tri-n-butyl phosphate (TBP). During chromatography, it appears that some of these compounds are eluted alongside Cd and cannot be removed by evaporation due to their high boiling points. When aliquots of the zero-ε reference material were processed through the purification procedure, refluxed in concentrated HNO3 and analyzed at minimum dilution (in 1 ml 0.1 M HNO3), they yielded Cd isotopic compositions (ε114/110Cd = 4.6 ± 3.4, 2SD, n = 4) that differed significantly from the expected value, despite the use of a double spike technique to correct for instrumental mass fractionation. This result was accompanied by a 35% reduction in instrumental sensitivity for Cd. With increasing dilution of the organic resin residue, both of these effects are reduced and they are insignificant when the eluted Cd is dissolved in ≥3 ml 0.1 M HNO3. Our results, furthermore, indicate that the isotopic artefacts are most likely related to anomalous mass bias behavior. Previous studies have shown that perchloric acid can be effective at avoiding such effects (Gault-Ringold and Stirling, 2012; K. C. Crocket, M. Lambelet, T. van de Flierdt, M. Rehkämper and L. F. Robinson, Chem. Geol., 2014, 374-375, 128-140), presumably by oxidizing the resin-derived organics, but there are numerous disadvantages to its use. Here we show that liquid-liquid extraction with n-heptane removes the organic compounds, dramatically improving quality of the Cd isotope data for samples that are analyzed at or close to minimum dilution factors. This technique is quick, simple and may be of use prior to analysis of other isotope systems where similar resins are employed.
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Affiliation(s)
- Katy Murphy
- Department of Earth Science and Engineering , Imperial College London , London SW7 2AZ , UK . ; Tel: +44 (0)2075947140
| | - Mark Rehkämper
- Department of Earth Science and Engineering , Imperial College London , London SW7 2AZ , UK . ; Tel: +44 (0)2075947140
| | - Katharina Kreissig
- Department of Earth Science and Engineering , Imperial College London , London SW7 2AZ , UK . ; Tel: +44 (0)2075947140
| | - Barry Coles
- Department of Earth Science and Engineering , Imperial College London , London SW7 2AZ , UK . ; Tel: +44 (0)2075947140
| | - Tina van de Flierdt
- Department of Earth Science and Engineering , Imperial College London , London SW7 2AZ , UK . ; Tel: +44 (0)2075947140
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9
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Application of non-traditional stable isotopes in analytical ecogeochemistry assessed by MC ICP-MS - A critical review. Anal Bioanal Chem 2015; 408:369-85. [DOI: 10.1007/s00216-015-9025-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/25/2015] [Accepted: 09/02/2015] [Indexed: 10/23/2022]
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