1
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Martin AJ, Kuang C, Wallschläger D. Expansion of the Conceptual Model for the Accumulation of Selenium in Lentic Food Chains to Include Redox-Controlled Generation and Diffusion of Selenite and Dissolved Organo-Selenium Compounds. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:2859-2869. [PMID: 35975431 DOI: 10.1002/etc.5465] [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: 04/12/2022] [Revised: 07/21/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
The controls governing the availability of reduced selenium (Se) species, namely selenite (Se[IV]) and dissolved organo-Se (DOSe), to primary producers at the sediment-water interface in depositional environments (i.e., lentic systems) were assessed through consideration of theoretical principles and field data. Selenite is generated in suboxic sediment porewater via the microbially mediated reduction of selenate (Se[IV]) and/or reductive dissolution of Se-bearing iron oxides. Field data for lentic environments demonstrate that the production of DOSe in sediment porewaters can also be redox- and depth-dependent. In this manner, the remobilization depths of Se(IV) and DOSe in depositional environments are dependent on the vertical redox gradient (dEh/dz), where deeper depths of remobilization are observed in less reducing sedimentary environments (lower dEh/dz). In turn, remobilization depth has a direct bearing on the concentration of dissolved Se(IV) and DOSe that may be realized at the sediment-water interface because the depth of reaction governs the diffusive path length, concentration gradient, and rate of diffusional transport toward the sediment-water interface. The principles that link sediment redox gradients, depth of remobilization, diffusive transport processes, and concentration of reduced Se species at the sediment-water interface have a direct bearing on the potential for Se uptake by primary producers in lentic food chains (e.g., phytoplankton, biofilms, bacteria). Overall, these processes complement the current conceptual "benthic detrital food chain" model that describes the accumulation of Se in lentic systems. Environ Toxicol Chem 2022;41:2859-2869. © 2022 SETAC.
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Affiliation(s)
- Alan J Martin
- Lorax Environmental Services, Vancouver, British Columbia, Canada
| | - Cheng Kuang
- Lorax Environmental Services, Vancouver, British Columbia, Canada
| | - Dirk Wallschläger
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada
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2
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Bordash MG, Pagliano E, LeBlanc KL, Kumkrong P, Wallschläger D, Mester Z. Determination of selenocyanate, selenate, and selenite in mining wastewater by GC-MS using sequential derivatization and extraction. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 745:140877. [PMID: 32726700 DOI: 10.1016/j.scitotenv.2020.140877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/24/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
Selenium speciation analysis is usually carried out using complex hyphenated analytical systems such as LC-ICP-MS. Here we present a novel selenium speciation approach based on a sequential derivatization and extraction combined with gas chromatography mass spectrometry for the simultaneous determination of selenite, selenate, and selenocyanate in aqueous mine wastewater samples. Selenocyanate was derivatized with triethyloxonium tetrafluoroborate to ethylselenocyanate, which was extracted into chloroform, following which the sample was split into two aliquots. One aliquot was acidified and 3,5-bis(trifluoromethyl)-o-phenylenediamine was used for the novel derivatization of selenite to 4,6-bis(trifluoromethyl)-2,1,3-benzoselenadiazole, for the determination of selenite. For the second aliquot, concentrated hydrochloric acid was added along with 4-nitro-o-phenylenediamine to simultaneously reduce selenate to selenite and derivatize the combined "selenite + selenate" fraction to 5-nitro-2,1,3-benzoselenadiazole. The benzoselenadiazoles were extracted with chloroform and all extracts were combined for GC-MS analysis. Low ng g-1 detection limits were reported for all three species. The method is unhindered by concentrations of chloride and sulphate up to 3%, as well as nitrate concentrations up to 3% for selenocyanate and selenite analysis, with minor losses in sensitivity for selenate up to 100 ppm nitrate, making the method particularly suitable for aqueous mine waste characterization. Quantitative trace selenium speciation was achieved using cost-effective materials and apparatus on a simple-to-operate benchtop instrument. The novel methodology was tested on gold mine wastewater samples; comparing to total selenium, a 63-149% recovery as the sum of species was observed. Additionally, this novel speciation approach was compared to LC-ICP-MS based selenium speciation and a reasonable agreement was found in the species distribution.
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Affiliation(s)
- Mitchell G Bordash
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada; Master of Instrumental Chemical Analysis Graduate Program, Trent University, Peterborough, Ontario, Canada
| | - Enea Pagliano
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada
| | - Kelly L LeBlanc
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada.
| | - Paramee Kumkrong
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada
| | - Dirk Wallschläger
- Water Quality Centre, School of the Environment, Department of Chemistry, Trent University, Peterborough, Ontario, Canada
| | - Zoltán Mester
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada
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3
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Pagliano E, LeBlanc KL, Mester Z. Selective Gas Chromatography Mass Spectrometry Method for Ultratrace Detection of Selenocyanate. Anal Chem 2019; 91:12162-12166. [PMID: 31464419 DOI: 10.1021/acs.analchem.9b02615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The recent interest in the determination of selenocyanate (SeCN-) in wastewater systems has spurred the development of analytical methods for its determination at the ultratrace level. Since most of the current procedures require complex and costly instrumental configurations, we have developed a simple and rapid gas chromatography tandem mass spectrometry (GC/MS/MS) method able to detect SeCN- in water samples with a LOD of 0.1 ng/g Se. A 1 mL volume of aqueous sample was buffered with sodium bicarbonate and treated with triethyloxonium tetrafluoroborate for conversion of the analyte into volatile EtSeCN. The derivatization yield was higher than 90%, and it could tolerate concentrations of chloride or sulfate up to 2%. The EtSeCN was extracted in chloroform and could be detected in electron ionization and also in negative chemical ionization mode with a further gain in signal-to-noise ratio by a factor of 2. The method was applied for the analysis of natural waters with quantitation of SeCN- in the low ng/g region. The Se13C15N- internal standard could be used for isotope dilution. Quantitative spike recoveries of 1 ng/g Se were obtained from seawater and river water, and 1 ng/g Se could be quantified within a standard uncertainty of 15%.
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Affiliation(s)
- Enea Pagliano
- National Research Council Canada , 1200 Montreal Road , Ottawa , Ontario K1A 0R6 , Canada
| | - Kelly L LeBlanc
- National Research Council Canada , 1200 Montreal Road , Ottawa , Ontario K1A 0R6 , Canada
| | - Zoltán Mester
- National Research Council Canada , 1200 Montreal Road , Ottawa , Ontario K1A 0R6 , Canada
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4
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Yu X, Liu C, Guo Y, Deng T. Speciation Analysis of Trace Arsenic, Mercury, Selenium and Antimony in Environmental and Biological Samples Based on Hyphenated Techniques. Molecules 2019; 24:E926. [PMID: 30866421 PMCID: PMC6429259 DOI: 10.3390/molecules24050926] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/22/2019] [Accepted: 02/28/2019] [Indexed: 12/20/2022] Open
Abstract
In order to obtain a well understanding of the toxicity and ecological effects of trace elements in the environment, it is necessary to determine not only the total amount, but also their existing species. Speciation analysis has become increasingly important in making risk assessments of toxic elements since the toxicity and bioavailability strongly depend on their chemical forms. Effective separation of different species in combination with highly sensitive detectors to quantify these particular species is indispensable to meet this requirement. In this paper, we present the recent progresses on the speciation analysis of trace arsenic, mercury, selenium and antimony in environmental and biological samples with an emphasis on the separation and detection techniques, especially the recent applications of high performance liquid chromatography (HPLC) hyphenated to atomic spectrometry or mass spectrometry.
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Affiliation(s)
- Xiaoping Yu
- Tianjin Key Laboratory of Marine Resources and Chemistry, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin 300457, China.
| | - Chenglong Liu
- Tianjin Key Laboratory of Marine Resources and Chemistry, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin 300457, China.
| | - Yafei Guo
- Tianjin Key Laboratory of Marine Resources and Chemistry, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin 300457, China.
| | - Tianlong Deng
- Tianjin Key Laboratory of Marine Resources and Chemistry, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin 300457, China.
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5
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LeBlanc KL, Kumkrong P, Mercier PHJ, Mester Z. Selenium analysis in waters. Part 2: Speciation methods. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 640-641:1635-1651. [PMID: 29935780 DOI: 10.1016/j.scitotenv.2018.05.394] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
In aquatic ecosystems, there is often no correlation between the total concentration of selenium present in the water column and the toxic effects observed in that environment. This is due, in part, to the variation in the bioavailability of different selenium species to organisms at the base of the aquatic food chain. The first part of this review (Kumkrong et al., 2018) discusses regulatory framework and standard methodologies for selenium analysis in waters. In this second article, we are reviewing the state of speciation analysis and importance of speciation data for decision makers in industry and regulators. We look in detail at fractionation methods for speciation, including the popular selective sequential hydride generation. We examine advantages and limitations of these methods, in terms of achievable detection limits and interferences from other matrix species, as well as the potential to over- or under-estimate operationally-defined fractions based on the various conversion steps involved in fractionation processes. Additionally, we discuss methods of discrete speciation (through separation methods), their importance in analyzing individual selenium species, difficulties associated with their implementation, as well as ways to overcome these difficulties. We also provide a brief overview of biological treatment methods for the remediation of selenium-contaminated waters. We discuss the importance of selenium speciation in the application of these methods and their potential to actually increase the bioavailability of selenium despite decreasing its total waterborne concentration.
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Affiliation(s)
- Kelly L LeBlanc
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada.
| | - Paramee Kumkrong
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada
| | - Patrick H J Mercier
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada
| | - Zoltán Mester
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, Canada
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6
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Donner MW, Siddique T. A rapid and sensitive IC-ICP-MS method for determining selenium speciation in natural waters. CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0637] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Selenium (Se) is an element monitored by water quality agencies worldwide. The challenge of assessing its presence in aquatic systems is its low concentrations (parts per trillion) and the need for determining its chemical speciation. A method was developed using an ion chromatograph (IC) paired with a quadrupole inductively coupled plasma mass spectrometer (ICP-MS) equipped with a hydrogen reaction cell to provide analysts with a rapid and sensitive method to measure Se speciation with suitable accuracy and precision. The Se species selenite (SeIV) and selenate (SeVI) were separated within a 5 min span using dilute nitric acid as a mobile phase in a step-wise gradient (50–400 mmol L−1) and quantified using 80Se isotope that yielded low limits of detection (<10 ng L−1). Spectral interference from plasma generated diatomic argon ions (40Ar2+; m/z = 80) on 80Se was eliminated by hydrogen gas (H2) in the reaction cell. Polyatomic 79Br1H+ (m/z = 80) did not interfere with 80Se for quantification of common aquatic Se species (SeVI and SeIV) due to different column retention times. Two organic species (methylselenocysteine and selenomethionine) commonly found in aquatic and terrestrial plant tissues were also tested to rule out possible chromatographic interference and explore the potential application to biological samples. Urban rainwater and Canadian river water samples were analyzed for Se species to demonstrate the applicability of the method. Owing to its ability to rapidly determine Se species in water samples at environmentally relevant concentrations, the method may be useful for monitoring agencies to routinely measure Se species in freshwater aquatic systems.
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Affiliation(s)
- Mark W. Donner
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2G7, Canada
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2G7, Canada
| | - Tariq Siddique
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2G7, Canada
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2G7, Canada
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7
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Ponton DE, Fortin C, Hare L. Organic selenium, selenate, and selenite accumulation by lake plankton and the alga Chlamydomonas reinhardtii at different pH and sulfate concentrations. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:2112-2122. [PMID: 29672902 DOI: 10.1002/etc.4158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/10/2018] [Accepted: 04/18/2018] [Indexed: 06/08/2023]
Abstract
Selenium (Se) concentrations measured in lake planktonic food chains (microplankton <64 μm, copepods, and Chaoborus larvae) were strongly correlated with the concentrations of dissolved organic Se. These correlations were strengthened slightly by adding the concentrations of dissolved selenate to those of organic Se. To better understand the role of Se species and the influence of water chemistry on Se uptake, we exposed the green alga Chlamydomonas reinhardtii to selenite, selenate, or selenomethionine at various H+ ion and sulfate concentrations under controlled laboratory conditions. At low sulfate concentrations, inorganic Se species (selenate >> selenite) were more readily accumulated by this alga than was selenomethionine. However, at higher sulfate concentrations the uptake of selenite was higher than that of selenate, whereas the uptake of selenomethionine remained unchanged. Although the pH of the exposure water did not influence the uptake of selenate by this alga, the accumulation of selenomethionine and selenite increased with pH because of their relative pH-related speciation. The Se concentrations that we measured in C. reinhardtii exposed to selenomethionine were 30 times lower than those that we measured in field-collected microplankton exposed in the same laboratory conditions. This difference is explained by the taxa present in the microplankton samples. Using the present laboratory measurements of Se uptake in microplankton and of natural Se concentrations in lake water allowed us to model Se concentrations in a lake pelagic food chain. Environ Toxicol Chem 2018;37:2112-2122. © 2018 SETAC.
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Affiliation(s)
- Dominic E Ponton
- Institut National de la Recherche Scientifique-Centre Eau, Terre et Environnement (INRS-ETE), Université du Québec, Quebec City, Quebec, Canada
| | - Claude Fortin
- Institut National de la Recherche Scientifique-Centre Eau, Terre et Environnement (INRS-ETE), Université du Québec, Quebec City, Quebec, Canada
| | - Landis Hare
- Institut National de la Recherche Scientifique-Centre Eau, Terre et Environnement (INRS-ETE), Université du Québec, Quebec City, Quebec, Canada
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8
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Martin AJ, Fraser C, Simpson S, Belzile N, Chen YW, London J, Wallschläger D. Hydrological and biogeochemical controls governing the speciation and accumulation of selenium in a wetland influenced by mine drainage. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:1824-1838. [PMID: 29480546 DOI: 10.1002/etc.4123] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/15/2018] [Accepted: 02/23/2018] [Indexed: 06/08/2023]
Abstract
Controls governing the speciation and accumulation of Se in a 3.7-ha marsh influenced by mine drainage were assessed through examination of water balance, water quality, sediment, and plant tissue components. Over the 8-mo study period (April through November, 2009), mean monthly flows ranged from 1600 to 2300 m3 d-1 (hydraulic retention time of 1-3 d). Total Se concentrations in the marsh outflow were lower than the inflow by 0.4 to 6.2 μg L-1 (mean difference = 3.3 μg L-1 ), illustrating Se removal. The Se accumulation pathways are illustrated by elevated concentrations of Se in sediments (3-35 mg kg-1 dry wt) as well as in below-ground (2-41 mg kg-1 dry wt; mean = 10 mg kg-1 dry wt) and above-ground (0.8-6.3 mg kg-1 dry wt; mean = 2 mg kg-1 dry wt) emergent plant tissues. Redox stratification in the shallow water column had a marked effect on Se speciation and behavior, illustrating bottom water removal of dissolved selenate in suboxic horizons and increased mobility of dissolved organo-Se. Mass balance data yielded inflow and outflow loading rates for Se of 27 and 23 g d-1 , respectively (net accumulation rate of 4 g d-1 or 0.11 mg m2 d-1 ). The rate of accumulation as calculated from the mass balance agrees with independently measured rates of Se accumulation in sediments for the site (3.6-8.1 g d-1 or 0.10-0.22 mg m-2 d-1 ). Environ Toxicol Chem 2018;37:1824-1838. © 2018 SETAC.
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Affiliation(s)
- Alan J Martin
- Lorax Environmental Services, Vancouver, British Columbia, Canada
| | - Colin Fraser
- Lorax Environmental Services, Vancouver, British Columbia, Canada
| | | | | | - Y-W Chen
- Laurentian University, Sudbury, Ontario, Canada
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9
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Selenium modification of β-lactoglobulin (β-Lg) and its biological activity. Food Chem 2016; 204:246-251. [DOI: 10.1016/j.foodchem.2016.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 12/01/2015] [Accepted: 01/06/2016] [Indexed: 01/03/2023]
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10
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Chen YW, Alzahrani A, Deng TL, Belzile N. Valence properties of tellurium in different chemical systems and its determination in refractory environmental samples using hydride generation - Atomic fluorescence spectroscopy. Anal Chim Acta 2015; 905:42-50. [PMID: 26755135 DOI: 10.1016/j.aca.2015.11.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 11/20/2015] [Accepted: 11/24/2015] [Indexed: 11/24/2022]
Abstract
Using HG - AFS as a powerful tool to study valence transformations of Te, we found that, in presence of HCl and at high temperature, Te can form volatile species and be lost during sample digestion and pre-reduction steps. It was also noticed that the chemical valences of Te can be modified under different chemical and digestion conditions and even by samples themselves with certain matrices. KBr can reduce Te(VI) to Te(IV) in 3.0 M HCl at 100 °C, but when HNO3 was >5% (v/v) in solution, Br2 was formed and caused serious interference to Te measurements. HCl alone can also pre-reduce Te(VI) to Te(IV), only when its concentration was ≥6.0 M (100 °C for 15min). Among 10 studied chemical elements, only Cu(2+) caused severe interference. Thiourea is an effective masking agent only when Cu(2+) concentration is equal or lower than 10 mg/L. Chemical reagents, chemical composition of sample, as well as the modes of digestion can greatly affect Te valences, reagent blanks and analytical precisions. A protocol of 2-step-digestion followed by an elimination of HF is proposed to minimize reagent blank and increase the signal/noise ratios. It is important to perform a preliminary test to confirm whether a pre-reduction step is necessary; this is especially true for samples with complex matrices such as those with high sulfide content. The analytical detection limits of this method in a pure solution and a solid sample were 100 ng/L and 0.10 ± 0.02 μg/g, respectively.
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Affiliation(s)
- Yu-Wei Chen
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario P3E 2C6, Canada
| | - Ali Alzahrani
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario P3E 2C6, Canada
| | - Tian-Long Deng
- College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin, China
| | - Nelson Belzile
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario P3E 2C6, Canada; Cooperative Freshwater Ecology Unit, Laurentian University, Sudbury, Ontario P3E 2C6, Canada.
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11
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Identification of trace levels of selenomethionine and related organic selenium species in high-ionic-strength waters. Anal Bioanal Chem 2015; 408:1033-42. [DOI: 10.1007/s00216-015-9124-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/29/2015] [Accepted: 10/15/2015] [Indexed: 10/22/2022]
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12
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Niane B, Guédron S, Moritz R, Cosio C, Ngom PM, Deverajan N, Pfeifer HR, Poté J. Human exposure to mercury in artisanal small-scale gold mining areas of Kedougou region, Senegal, as a function of occupational activity and fish consumption. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:7101-11. [PMID: 25501641 DOI: 10.1007/s11356-014-3913-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/24/2014] [Indexed: 05/24/2023]
Abstract
We investigated mercury (Hg) exposure of food web and humans in the region of Kedougou, Senegal, where Hg is used for gold amalgamation in artisanal small-scale gold mining (ASGM). For this purpose, total mercury (THg) concentration was determined in eight fish species and two shellfish species from Gambia River and in human hair from 111 volunteers of different age and sex, living in urban locations (Kedougou and Samekouta) or in ASGM areas (Tinkoto and Bantako). THg concentrations in fish samples range from 0.03 to 0.51 mg kg(-1) wet weight (ww) and 0.5 to 1.05 mg kg(-1) ww for shellfish. THg concentrations in fish are below the WHO guideline of 0.5 mg kg(-1) ww, whereas 100 % of shellfish are above this safety guideline. In the entire set of fish and shellfish samples, we documented a decrease of THg concentrations with increasing selenium to mercury (Se:Hg) ratio suggesting a protection of Se against Hg. However, local population consuming fish from the Gambia River in the two ASGM areas have higher THg concentrations (median = 1.45 and 1.5 mg kg(-1) at Bantako and Tinkoto) in hair than those from others localities (median = 0.42 and 0.32 mg kg(-1) at Kedougou town and Samekouta) who have diverse diets. At ASGM sites, about 30 % of the local population present Hg concentrations in hair exceeding 1 mg kg(-1), defined as the reference concentration of Hg in hair. We also evidence a higher exposure of women to Hg in the Tinkoto ASGM site due to the traditional distribution of daily tasks where women are more involved in the burning of amalgams. The discrepancy between the calculated moderate exposure through fish consumption and the high Hg concentrations measured in hair suggest that fish consumption is not the only source of Hg exposure and that further studies should focus on direct exposure to elemental Hg of population living at ASGM sites.
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Affiliation(s)
- Birane Niane
- Earth and Environmental Sciences, University of Geneva, rue des Maraîchers 13, 1205, Geneva, Switzerland,
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13
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Shih TT, Lin CH, Hsu IH, Chen JY, Sun YC. Development of a Titanium Dioxide-Coated Microfluidic-Based Photocatalyst-Assisted Reduction Device to Couple High-Performance Liquid Chromatography with Inductively Coupled Plasma-Mass Spectrometry for Determination of Inorganic Selenium Species. Anal Chem 2013; 85:10091-8. [DOI: 10.1021/ac400934e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tsung-Ting Shih
- Department
of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 30013 Hisnchu, Taiwan
| | - Cheng-Hsing Lin
- Department
of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 30013 Hisnchu, Taiwan
| | - I-Hsiang Hsu
- Center for Measurement Standards, Industrial Technology Research Institute, 30011 Hsinchu, Taiwan
| | - Jian-Yi Chen
- Department
of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 30013 Hisnchu, Taiwan
| | - Yuh-Chang Sun
- Department
of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 30013 Hisnchu, Taiwan
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14
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Ponton DE, Hare L. Relating selenium concentrations in a planktivore to selenium speciation in lakewater. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 176:254-260. [PMID: 23454587 DOI: 10.1016/j.envpol.2013.01.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 01/16/2013] [Accepted: 01/22/2013] [Indexed: 06/01/2023]
Abstract
We measured selenium (Se) speciation in the waters of 16 lakes located near two major metal smelters and compared it to Se concentrations in a potential biomonitor, the planktivorous insect Chaoborus. We used this sentinel because planktonic algae and crustaceans, which are lower in the trophic chain leading to Chaoborus, are more difficult to separate and identify to species, whereas many fish species are not obligate planktivores. Percentages of selenate and organo-Se were generally higher in acidic lakes, whereas those of selenite were usually greater in alkaline waters. Chaoborus Se concentrations varied widely among lakes and, with the exception of a single high-sulfate lake, were significantly and highly correlated with those of dissolved organo-Se plus selenate (Se(VI)). We suggest that Chaoborus larvae would be highly effective for monitoring the Se-exposure of planktonic food webs in lakes.
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Affiliation(s)
- Dominic E Ponton
- Institut national de recherche scientifique - Eau Terre Environnement, Université du Québec, 490 rue de Couronne, Quebec City, QC, Canada G1K 9A9
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15
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Truong HYT, Chen YW, Belzile N. Effect of sulfide, selenite and mercuric mercury on the growth and methylation capacity of the sulfate reducing bacterium Desulfovibrio desulfuricans. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 449:373-84. [PMID: 23454698 DOI: 10.1016/j.scitotenv.2013.01.054] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 05/09/2023]
Abstract
Cultures of the sulfate reducing bacteria Desulfovibrio desulfuricans were grown under anoxic conditions to study the effect of added sulfide, selenite and mercuric ions. A chemical trap consisting in a CuSO4 solution was used to control the poisoning effect induced by the bacterial production of hydrogen sulfide via the precipitation of CuS. Following the addition of Hg(2+), the formation of methylmercury (MeHg) was correlated to bacterial proliferation with most of MeHg found in the culture medium. A large fraction (50-80%) of added Hg(2+) to a culture ended up in a solid phase (Hg(0) and likely HgS) limiting its bioavailability to cells with elemental Hg representing ~40% of the solid. Following the addition of selenite, a small fraction was converted into Se(0) inside the cells and, even though the conversion to this selenium species increased with the increase of added selenite, it never reached more than 49% of the added amount. The formation of volatile dimethylselenide is suggested as another detoxification mechanism. In cultures containing both added selenite and mercuric ions, elemental forms of the two compounds were still produced and the increase of selenium in the residual fraction of the culture suggests the formation of mercuric selenite limiting the bioavailability of both elements to cells.
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Affiliation(s)
- Hoang-Yen T Truong
- Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6
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Martin AJ, Simpson S, Fawcett S, Wiramanaden CIE, Pickering IJ, Belzile N, Chen YW, London J, Wallschläger D. Biogeochemical mechanisms of selenium exchange between water and sediments in two contrasting lentic environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:2605-2612. [PMID: 21446766 DOI: 10.1021/es103604p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The biogeochemical mechanisms of Se exchange between water and sediments in two contrasting lentic environments were assessed through examination of Se speciation in the water column, porewater, and sediment. High-resolution (7 mm) vertical profiles of <0.45 μm Se species across the sediment-water interface demonstrate that the behavior of dissolved Se(VI), Se(IV), and organo-Se are closely linked to redox conditions as revealed by porewater profiles of redox-sensitive species (dissolved O2, NO3-, Fe, Mn, SO4(2-), and ΣH2S). At both sites Se(VI) is removed from solution in suboxic near-surface porewaters demonstrating that the sediments are serving as diffusive sinks for Se. X-ray absorption near edge spectroscopy (XANES) of sediments suggests that elemental Se and organo-Se represent the dominant sedimentary sinks for dissolved Se. Dissolved Se(IV) and organo-Se are released to porewaters in the near-surface sediments resulting in the diffusive transport of these species into the water column, where between-site differences in the depths of release can be linked to differences in redox zonation. The presence or absence of emergent vegetation is proposed to present a dominant control on sedimentary redox conditions as well as on the recycling and persistence of reduced Se species in bottom waters.
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Affiliation(s)
- Alan J Martin
- Lorax Environmental Services Ltd., Vancouver, British Columbia V6J 3H9, Canada.
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Simmons DBD, Wallschläger D. Release of reduced inorganic selenium species into waters by the green fresh water algae Chlorella vulgaris. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:2165-2171. [PMID: 21341693 DOI: 10.1021/es103337p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The common green fresh water algae Chlorella vulgaris was exposed to starting concentrations of 10 μg/L selenium in the form of selenate, selenite, or selenocyanate (SeCN(-)) for nine days in 10% Bold's basal medium. Uptake of selenate was more pronounced than that of selenite, and there was very little uptake of selenocyanate. Upon uptake of selenate, significant quantities of selenite and selenocyanate were produced by the algae and released back into the growth medium; no selenocyanate was released after selenite uptake. Release of the reduced metabolites after selenate exposure appeared to coincide with increasing esterase activity in solution, indicating that cell death (lysis) was the primary emission pathway. This is the first observation of biotic formation of selenocyanate and its release into waters from a nonindustrial source. The potential environmental implications of this laboratory observation are discussed with respect to the fate of selenium in impacted aquatic systems, the ecotoxicology of selenium bioaccumulation, and the interpretation of environmental selenium speciation data generated, using methods incapable of positively identifying reduced inorganic selenium species, such as selenocyanate.
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Zhao QX, Chen YW, Belzile N, Wang M. Low volume microwave digestion and direct determination of selenium in biological samples by hydride generation-atomic fluorescence spectrometry. Anal Chim Acta 2010; 665:123-8. [DOI: 10.1016/j.aca.2010.03.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/12/2010] [Accepted: 03/18/2010] [Indexed: 11/26/2022]
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Yang DY, Ye X, Chen YW, Belzile N. Inverse relationships between selenium and mercury in tissues of young walleye (Stizosedion vitreum) from Canadian boreal lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:1676-1683. [PMID: 20006995 DOI: 10.1016/j.scitotenv.2009.11.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 11/20/2009] [Accepted: 11/22/2009] [Indexed: 05/28/2023]
Abstract
The concentrations of total mercury (Hg), methylmercury (MeHg) and total selenium (Se) were determined in muscle, liver and brain tissues of young-of-the-year walleye (Stizosedion vitreum) specimens collected from 8 boreal lakes that are located within 107km around the Sudbury smelters in Ontario, Canada. Dry weight basis concentrations of Hg were highest in muscle and lowest in brain (p<0.05), those of MeHg were higher in muscle than in liver and brain but there was no significant difference between liver and brain (p<0.05). The highest Se concentrations were found in liver and the lowest in brain (p<0.05). Considering the biomass of the studied tissues, muscle was the part of the body where most of Hg, MeHg and Se were accumulated. In fish muscle, the percentage of MeHg over Hg was the highest and this percentage was the lowest in liver. The concentrations of Hg, MeHg and Se in the studied tissues were closely related to the concentrations of total dissolved Se in lake waters which vary with the distance of the lakes from the smelters. Thresholds of Se concentrations in tissues were revealed (6.2, 12.0 and 3.5mgkg(-1) dry wt., for muscle, liver and brain, respectively), above which a significant reduction of MeHg concentrations was observed in all studied tissues compared to lower Se levels in the same tissues. Based on the collected information and data analysis, possible mechanisms for the biological processes behind the observed inverse relationships between Se and Hg in fish tissues are discussed.
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Affiliation(s)
- Dan-Yi Yang
- Department of Chemistry and Biochemistry, Laurentian University, Ontario, Canada
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Wallschläger D, Feldmann J. Formation, Occurrence, Significance, and Analysis of Organoselenium and Organotellurium Compounds in the Environment. ORGANOMETALLICS IN ENVIRONMENT AND TOXICOLOGY 2010. [DOI: 10.1039/9781849730822-00319] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Among all environmentally-relevant trace elements, selenium has one of the most diverse organic chemistries. It is also one of the few trace elements that may biomagnify in food chains under certain conditions. Yet, the exact chemical forms of selenium involved in the uptake into organisms and transfer to higher trophic levels, as well as the biochemical mechanisms that lead to their subsequent metabolism in organisms, are still not well understood. This is in part due to the analytical challenges associated with measuring the myriad of discrete Se species occurring in organisms. While there are generalized concepts of selenium metabolism, there is a lack of conclusive analytical evidence supporting the existence of many postulated intermediates. Likewise, there is a disconnect between the major selenium species encountered in abiotic compartments (waters, soils, and sediment), and those found in organisms, which renders the qualitative and quantitative description of the bioaccumulation process uncertain. Here, we summarize the knowledge on important selenium and tellurium species in all environmental compartments, and identify gaps and uncertainties in the existing body of knowledge, with emphasis on problems associated with past and current analytical methodology.
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Affiliation(s)
- Dirk Wallschläger
- Environmental & Resource Sciences Program and Department of Chemistry, Trent University 1600 West Bank Dr. Peterborough ON K9J 7B8 Canada
| | - Jörg Feldmann
- Trace Element Speciation Laboratory (TESLA), College of Physical Science, University of Aberdeen Meston Walk Aberdeen Scotland AB24 3UE UK
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Liu S, Kokot S, Will G. Photochemistry and chemometrics—An overview. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2009. [DOI: 10.1016/j.jphotochemrev.2010.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gonzalvez A, Cervera M, Armenta S, de la Guardia M. A review of non-chromatographic methods for speciation analysis. Anal Chim Acta 2009; 636:129-57. [DOI: 10.1016/j.aca.2009.01.065] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 01/28/2009] [Accepted: 01/28/2009] [Indexed: 11/17/2022]
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Chen YW, Truong HYT, Belzile N. Abiotic formation of elemental selenium and role of iron oxide surfaces. CHEMOSPHERE 2009; 74:1079-1084. [PMID: 19062070 DOI: 10.1016/j.chemosphere.2008.10.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 10/24/2008] [Accepted: 10/27/2008] [Indexed: 05/27/2023]
Abstract
The possible abiotic reduction of selenite to form elemental Se was studied under controlled conditions in the presence of ferrous iron. The reduction of selenite and formation of Se (0) was found to be a surface-mediated reaction by iron oxides. Without the presence of the reactive surface of freshly precipitated iron oxides, the reduction reaction could not be detected, even under a well controlled low oxygen environment (30 ppmv). Our results clearly illustrate the crucial role of iron oxide in this redox process. In lake sediments, the complex sediment matrix seems to strongly adsorb SeO(2-) and make it less available for reduction into Se(0). When lake sediments were submitted to UV irradiation to eliminate bacteria, the percentage of iron oxides increased and it was found that higher levels of iron oxides, generated by the UV treatment, correlated with the higher formation of Se(0). Moreover, the results of our field studies on two distinctively different lake sediments also showed a strong influence of iron oxides on the formation of elemental Se, which agrees well with our laboratory simulations.
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Affiliation(s)
- Yu-Wei Chen
- Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E2C6, Canada
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