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Webb AN, Antipova O, Shughoury S, Farfel JM, Bennett DA, Du Y, Zheng W, Nie LH. Mercury and selenium distribution in human brain tissue using synchrotron micro-X-ray fluorescence. Metallomics 2024; 16:mfae018. [PMID: 38664065 PMCID: PMC11064728 DOI: 10.1093/mtomcs/mfae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
Mercury is a well-recognized environmental contaminant and neurotoxin, having been associated with a number of deleterious neurological conditions including neurodegenerative diseases, such as Alzheimer's disease. To investigate how mercury and other metals behave in the brain, we used synchrotron micro-X-ray fluorescence to map the distribution pattern and quantify concentrations of metals in human brain. Brain tissue was provided by the Rush Alzheimer's Disease Center and samples originated from individuals diagnosed with Alzheimer's disease and without cognitive impairment. Data were collected at the 2-ID-E beamline at the Advanced Photon Source at Argonne National Laboratory with an incident beam energy of 13 keV. Course scans were performed at low resolution to determine gross tissue features, after which smaller regions were selected to image at higher resolution. The findings revealed (1) the existence of mercury particles in the brain samples of two subjects; (2) co-localization and linear correlation of mercury and selenium in all particles; (3) co-localization of these particles with zinc structures; and (4) association with sulfur in some of these particles. These results suggest that selenium and sulfur may play protective roles against mercury in the brain, potentially binding with the metal to reduce the induced toxicity, although at different affinities. Our findings call for further studies to investigate the relationship between mercury, selenium, and sulfur, as well as the potential implications in Alzheimer's disease and related dementias.
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Affiliation(s)
- Alexis N Webb
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Olga Antipova
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Serena Shughoury
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Jose M Farfel
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Yansheng Du
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Wei Zheng
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Linda H Nie
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
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2
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Adams WJ, Duguay A. Selenium-mercury interactions and relationship to aquatic toxicity: A review. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2024. [PMID: 38578152 DOI: 10.1002/ieam.4918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 04/06/2024]
Abstract
A review of the literature pertaining to selenium-mercury (Se/Hg) interactions in aquatic species was performed to provide insight into the mechanisms allowing for the reported changes in bioaccumulation and toxicity that have been observed when the two elements occur at elevated concentrations. Selenium (Se) has been shown to protect against mercury (Hg) toxicity in all animal models evaluated (fish, birds, mammals, and plants). To explore the interaction between the two elements, data are presented on concentrations of both elements in wild-caught fish at numerous locations. The data show that most fish have Se/Hg ratios >1.0. The importance of this ratio has been reported, with suggestions that the protective interaction is due in large part to the formation of HgSe. Data show that when the Se/Hg molar ratio is <1.0 in the diet of fish and animals, Hg toxicity will be expressed, provided that the Hg concentration is sufficiently high. This toxicity is likely the result of Se deficiency leading to an excess of reactive oxygen species. Laboratory fish toxicity studies reviewed show that Se toxicity can be reduced or eliminated when Hg is added to the diet in moderate amounts. Field studies have shown reduced accumulation of Hg when Se concentrations are increased. When Hg in the diet is significantly elevated (usually >10 µg/g), toxicity is expressed regardless of the Se present. Likewise, amelioration of Se toxicity by Hg occurs over a limited range. Tissue thresholds for Se toxicity have been derived primarily from studies where fish eggs were extracted from wild fish and embryo deformities were observed; however, the amount of Hg in the fish or ovaries was not considered, which could lead to uncertainty in the toxicity threshold. It is recommended that both elements be measured and evaluated when performing risk assessments and setting water quality criteria. Integr Environ Assess Manag 2024;00:1-11. © 2024 SETAC.
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Wan Y, Liu J, Zhuang Z, Wang Q, Li H. Heavy Metals in Agricultural Soils: Sources, Influencing Factors, and Remediation Strategies. TOXICS 2024; 12:63. [PMID: 38251018 PMCID: PMC10819638 DOI: 10.3390/toxics12010063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/23/2024]
Abstract
Soil heavy metal pollution is a global environmental challenge, posing significant threats to eco-environment, agricultural development, and human health. In recent years, advanced and effective remediation strategies for heavy metal-contaminated soils have developed rapidly, and a systematical summarization of this progress is important. In this review paper, first, the anthropogenic sources of heavy metals in agricultural soils, including atmospheric deposition, animal manure, mineral fertilizers, and pesticides, are summarized. Second, the accumulation of heavy metals in crops as influenced by the plant characteristics and soil factors is analyzed. Then, the reducing strategies, including low-metal cultivar selection/breeding, physiological blocking, water management, and soil amendment are evaluated. Finally, the phytoremediation in terms of remediation efficiency and applicability is discussed. Therefore, this review provides helpful guidance for better selection and development of the control/remediation technologies for heavy metal-contaminated agricultural soils.
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Affiliation(s)
| | | | | | | | - Huafen Li
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Key Laboratory of Plant-Soil Interactions of the Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; (Y.W.); (J.L.); (Z.Z.); (Q.W.)
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Weng M, Dolgova NV, Vogt LI, Qureshi M, Sokaras D, Kroll T, Saitō H, O'Donoghue JL, Watson GE, Myers GJ, Sekikawa T, Pickering IJ, George GN. Synchrotron speciation of umbilical cord mercury and selenium after environmental exposure in Niigata. Neurotoxicology 2024; 100:117-123. [PMID: 38128735 DOI: 10.1016/j.neuro.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/09/2023] [Accepted: 12/17/2023] [Indexed: 12/23/2023]
Abstract
The insidious and deadly nature of mercury's organometallic compounds is informed by two large scale poisonings due to industrial mercury pollution that occurred decades ago in Minamata and Niigata, Japan. The present study examined chemical speciation for both mercury and selenium in a historic umbilical cord sample from a child born to a mother who lived near the Agano River in Niigata. The mother had experienced mercury exposure leading to more than 50 ppm mercury measured in her hair and was symptomatic 9 years prior to the birth. We sought to determine the mercury and selenium speciation in the child's cord using Hg Lα1 and Se Kα1 high-energy resolution fluorescence detected X-ray absorption spectroscopy, the chemical speciation of mercury was found to be predominantly organometallic and coordinated to a thiolate. The selenium was found to be primarily in an organic form and at levels higher than those of mercury, with no evidence of mercury-selenium chemical species. Our results are consistent with mercury exposure at Niigata being due to exposure to organometallic mercury species.
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Affiliation(s)
- Monica Weng
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V Dolgova
- Calibr - California Institute for Biomedical Research, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Linda I Vogt
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Muhammad Qureshi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | | | - John L O'Donoghue
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Gene E Watson
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA; Eastman Institute for Oral Health, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Gary J Myers
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA; Departments of Neurology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Tomoko Sekikawa
- Department of Internal Medicine, Nuttari Clinic, 6-4-12 Nuttarihigasi, Chuo-ku, Niigata 950-0075, Japan
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada; Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada; Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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5
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James AK, Popescu BF, Weng M, Myers GJ, O'Donoghue JL, Watson GE, Pickering IJ, George GN. Synchrotron X-ray methods in the study of mercury neurotoxicology. Neurotoxicology 2023; 99:129-138. [PMID: 37802190 DOI: 10.1016/j.neuro.2023.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/22/2023] [Accepted: 10/04/2023] [Indexed: 10/08/2023]
Abstract
In situ methods are valuable in all fields of research. In toxicology, the importance of dose is well known, elevating the need for in situ techniques to measure levels of toxicants and their byproducts in precise anatomically identifiable locations. More recently, additional emphasis has been placed on the value of techniques which can detect chemical form or speciation, which is equally important in the toxicology of a chemical compound. Many important but conventional methods risk losing valuable information due to extractions, digestions, or the general reliance on mobile phases. Few analytical tools possess the power and diversity of X-ray methods as in-situ methods. Here we present an overview, intended for toxicologists and pathologists, of a variety of synchrotron X-ray methods for determining in situ chemical form and distribution of heavier elements. The versatility and range of these synchrotron techniques, which are both established and emerging, is demonstrated in the context of the study of neurotoxicology of mercury, a global pollutant with the ability to harm both human health and the environment.
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Affiliation(s)
- Ashley K James
- Cameco MS Neuroscience Research Centre, University of Saskatchewan, Saskatoon City Hospital, Saskatoon, SK S7K 0M7, Canada; Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Bogdan F Popescu
- Cameco MS Neuroscience Research Centre, University of Saskatchewan, Saskatoon City Hospital, Saskatoon, SK S7K 0M7, Canada
| | - Monica Weng
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2, Canada
| | - Gary J Myers
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Departments of Neurology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - John L O'Donoghue
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - Gene E Watson
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Eastman Institute for Oral Health, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2, Canada; Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada; Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2, Canada; Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada; Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada.
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6
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Selenol (-SeH) as a target for mercury and gold in biological systems: Contributions of mass spectrometry and atomic spectroscopy. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Suzuki Y, Kondo M, Akiyama H, Ogra Y. Presence of nano-sized mercury-containing particles in seafoods, and an estimate of dietary exposure. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 307:119555. [PMID: 35654251 DOI: 10.1016/j.envpol.2022.119555] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
The toxicity of nano-sized particles of mercury (NP-Hg), which are thought to be generated during the detoxification of methyl mercury (MeHg), may differ from that of MeHg, elemental Hg (Hg0), and inorganic Hg (I-Hg). From a human health perspective, it is important to evaluate the presence of NP-Hg in seafoods. We investigated the in vivo formation of NP-Hg in fish and shellfish, which are the main sources of Hg exposure in humans. NP-Hg was measured in 90 fish samples with single-particle inductively coupled plasma mass spectrometry (spICP-MS) after enzyme degradation with pancreatin and lipase. In addition to NP-Hg, total Hg (T-Hg), MeHg, and selenium (Se) concentrations were evaluated. Transient Hg signals were detected as nanoparticles from almost all samples by using spICP-MS. Higher particle number concentrations (CPN) were observed in the tuna-swordfish group than in the shellfish group (17.7 × 107 vs. 1.2 × 106 particles/g, respectively). Although the CPN and maximum particle mass increased significantly with increasing T-Hg concentration, the increase in CPN was greater than those in maximum particle mass. Assuming that the NP-Hg detected was HgSe (tiemannite) and spherical based on previous reports, the maximum particle diameter was estimated to be 89 nm. The mean dietary exposures to NP-Hg, T-Hg, and MeHg were estimated to be 0.067, 5.75, and 5.32 μg/person per day, respectively. Generation of NP-Hg was inferred to be widespread in marine animals, with a preferential increase in the number of particles rather than an increase in particle size. The mean dietary exposure to NP-Hg in Japanese people was estimated to be 1.2 ng/kg body weight (BW) per day. Compared to PTWI of 4 μg/kg BW per week (0.57 μg/kg BW per day) derived by JECFA (2011), the health risk from redissolved I-Hg from NP-Hg is small.
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Affiliation(s)
- Yoshinari Suzuki
- Division of Foods, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Midori Kondo
- Division of Foods, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Hiroshi Akiyama
- Division of Foods, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan; Department of Analytical Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Yasumitsu Ogra
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba, 260-8675, Japan
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8
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James AK, Dolgova NV, Nehzati S, Korbas M, Cotelesage JJH, Sokaras D, Kroll T, O’Donoghue JL, Watson GE, Myers GJ, Pickering IJ, George GN. Molecular Fates of Organometallic Mercury in Human Brain. ACS Chem Neurosci 2022; 13:1756-1768. [PMID: 35543423 PMCID: PMC9977140 DOI: 10.1021/acschemneuro.2c00166] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mercury is ubiquitous in the environment, with rising levels due to pollution and climate change being a current global concern. Many mercury compounds are notorious for their toxicity, with the potential of organometallic mercury compounds for devastating effects on the structures and functions of the central nervous system being of particular concern. Chronic exposure of human populations to low levels of methylmercury compounds occurs through consumption of fish and other seafood, although the health consequences, if any, from this exposure remain controversial. We have used high energy resolution fluorescence detected X-ray absorption spectroscopy to determine the speciation of mercury and selenium in human brain tissue. We show that the molecular fate of mercury differs dramatically between individuals who suffered acute organometallic mercury exposure (poisoning) and individuals with chronic low-level exposure from a diet rich in marine fish. For long-term low-level methylmercury exposure from fish consumption, mercury speciation in brain tissue shows methylmercury coordinated to an aliphatic thiolate, resembling the coordination environment observed in marine fish. In marked contrast, for short-term high-level exposure, we observe the presence of biologically less available mercuric selenide deposits, confirmed by X-ray fluorescence imaging, as well as mercury(II)-bis-thiolate complexes, which may be signatures of severe poisoning in humans. These differences between low-level and high-level exposures challenge the relevance of studies involving acute exposure as a proxy for low-level chronic exposure.
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Affiliation(s)
- Ashley K. James
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V. Dolgova
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Susan Nehzati
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Malgorzata Korbas
- Canadian Light Source, 44 Innovation Blvd, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Julien J. H. Cotelesage
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - John L. O’Donoghue
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Gene E. Watson
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Eastman Institute for Oral Health, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Gary J. Myers
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Departments of Neurology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Ingrid J. Pickering
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N. George
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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Nehzati S, Dolgova NV, Young CG, James AK, Cotelesage JJH, Sokaras D, Kroll T, Qureshi M, Pickering IJ, George GN. Mercury Lα1 High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy: A Versatile Speciation Probe for Mercury. Inorg Chem 2022; 61:5201-5214. [PMID: 35073478 PMCID: PMC9962031 DOI: 10.1021/acs.inorgchem.1c03196] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mercury is in some sense an enigmatic element. The element and some of its compounds are a natural part of the biogeochemical cycle; while many of these can be deadly poisons at higher levels, environmental levels in the absence of anthropogenic contributions would generally be below the threshold for concern. However, mercury pollution, particularly from burning fossil fuels such as coal, is providing dramatic and increasing emissions into the environment. Because of this, the environmental chemistry and toxicology of mercury are of growing importance, with the fate of mercury being vitally dependent upon its speciation. X-ray absorption spectroscopy (XAS) provides a powerful tool for in situ chemical speciation, but is severely limited by poor spectroscopic energy resolution. Here, we provide a systematic examination of mercury Lα1 high energy resolution fluorescence detected XAS (HERFD-XAS) as an approach for chemical speciation of mercury, in quantitative comparison with conventional Hg LIII-edge XAS. We show that, unlike some lighter elements, chemical shifts in the Lα1 X-ray fluorescence energy can be safely neglected, so that mercury Lα1 HERFD-XAS can be treated simply as a high-resolution version of conventional XAS. We present spectra of a range of mercury compounds that may be relevant to the environmental and life science research and show that density functional theory can produce adequate simulations of the spectra. We discuss strengths and limitations of the method and quantitatively demonstrate improvements both in speciation for complex mixtures and in background rejection for low concentrations.
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Affiliation(s)
- Susan Nehzati
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Present Address: MAX IV Laboratory, Lund University, Fotongatan 2, 221 00 Lund, Sweden
| | - Natalia V. Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Present Address: Calibr - California Institute for Biomedical Research, Scripps Research, La Jolla, California 92037, USA
| | - Charles G. Young
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Ashley K. James
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Julien J. H. Cotelesage
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Muhammad Qureshi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Ingrid J. Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N. George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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10
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Leitão RG, Silva MP, Diniz MS, Guerra M. Mapping the distribution of mercury (II) chloride in zebrafish organs by benchtop micro-energy dispersive X-ray fluorescence: A proof of concept. J Trace Elem Med Biol 2022; 69:126874. [PMID: 34700157 DOI: 10.1016/j.jtemb.2021.126874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 09/06/2021] [Accepted: 10/12/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND Mercury (Hg) is a globally ubiquitous pollutant and one of the most dangerous metal contaminants, which presents a high risk of bioaccumulation in living organisms. In this study, we mapped the distribution of Hg and other trace elements in zebrafish (Danio rerio), which were exposed to mercury (II) chloride in order to assess its toxicity, bioaccumulation and distribution in fish organs. METHODS Adult zebrafish were exposed for 7 days to different concentrations of mercury (II) chloride and the elemental distribution was obtained through the micro-energy dispersive X-ray fluorescence technique (μ-EDXRF). RESULTS The results showed that Hg levels, measured in fish tissues, were indicative of bioaccumulation within some of its organs (e.g. visceral mass, gills), and that the physiological processes of accumulation were highly dose-dependent. In addition, the results showed higher concentrations of Hg in the gills. Moreover, other trace elements (e.g. Fe, Cu and Zn) levels were not altered after fish exposure to mercury(II) chloride. CONCLUSION The μ-EDXRF results were assessed along with the determination of some oxidative stress biomarkers (e.g. antioxidant enzymes) to understand the effects behind the Hg bioaccumulation and toxicity. These results suggest that the metabolic changes in zebrafish due to the exposure to Hg are consistent with oxidative stress.
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Affiliation(s)
- Roberta G Leitão
- LIBPhys - UNL, Laboratory for Instrumentation, Biomedical Engineering and Radiation Physics, Physics Department, School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal.
| | - Maria P Silva
- LIBPhys - UNL, Laboratory for Instrumentation, Biomedical Engineering and Radiation Physics, Physics Department, School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Mario S Diniz
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal; UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry/Department of Life Sciences, School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Mauro Guerra
- LIBPhys - UNL, Laboratory for Instrumentation, Biomedical Engineering and Radiation Physics, Physics Department, School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
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11
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Lanctôt CM, Cresswell T, Lombi E, Bennett WW. Synchrotron-Based Imaging Reveals the Fate of Selenium in Striped Marsh Frog Tadpoles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:11848-11858. [PMID: 34382781 DOI: 10.1021/acs.est.1c02028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Synchrotron-based X-ray fluorescence microscopy (XFM) coupled with X-ray absorption near-edge structure (XANES) imaging was used to study selenium (Se) biodistribution and speciation in Limnodynastes peronii tadpoles. Tadpoles were exposed to dissolved Se (30 μg/L) as selenite (SeIV) or selenate (SeVI) for 7 days followed by 3 days of depuration. High-resolution elemental maps revealed that Se partitioned primarily in the eyes (specifically the eye lens, iris, and retinal pigmented epithelium), digestive and excretory organs of SeIV-exposed tadpoles. Speciation analysis confirmed that the majority of accumulated Se was converted to organo-Se. Multielement analyses provided new information on Se colocalization and its impact on trace element homeostasis. New insights into the fate of Se on a whole organism scale contribute to our understanding of the mechanisms and risks associated with Se pollution.
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Affiliation(s)
- Chantal M Lanctôt
- Australian Rivers Institute, Griffith University, Southport, Queensland 4215, Australia
- School of Environment and Science, Griffith University, Southport, Queensland 4215, Australia
| | - Tom Cresswell
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Enzo Lombi
- Future Industries Institute, University of South Australia, Adelaide, South Australia 5095, Australia
| | - William W Bennett
- School of Environment and Science, Griffith University, Southport, Queensland 4215, Australia
- Coastal and Marine Research Centre, Cities Research Institute, Griffith University, Southport, Queensland 4215, Australia
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12
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Nehzati S, Dolgova NV, James AK, Cotelesage JJH, Sokaras D, Kroll T, George GN, Pickering IJ. High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy: An Analytical Method for Selenium Speciation. Anal Chem 2021; 93:9235-9243. [PMID: 34164981 DOI: 10.1021/acs.analchem.1c01503] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Selenium is in many ways an enigmatic element. It is essential for health but toxic in excess, with the difference between the two doses being narrower than for any other element. Environmentally, selenium is of concern due to its toxicity. As the rarest of the essential elements, its low levels often provide challenges to the analytical chemist. X-ray absorption spectroscopy (XAS) provides a powerful tool for in situ chemical speciation but is severely limited by poor spectroscopic resolution arising from core-hole lifetime broadening. Here we explore selenium Kα1 high energy resolution fluorescence detected XAS (HERFD-XAS) as a novel approach for chemical speciation of selenium, in comparison with conventional Se K-edge XAS. We present spectra of a range of selenium species relevant to environmental and life science studies, including spectra of seleno-amino acids, which show strong similarities with S K-edge XAS of their sulfur congeners. We discuss strengths and limitations of HERFD-XAS, showing improvements in both speciation performance and low concentration detection. We also develop a simple method to correct fluorescence self-absorption artifacts, which is generally applicable to any HERFD-XAS experiment.
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Affiliation(s)
- Susan Nehzati
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Ashley K James
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Julien J H Cotelesage
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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13
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Manceau A, Gaillot AC, Glatzel P, Cherel Y, Bustamante P. In Vivo Formation of HgSe Nanoparticles and Hg-Tetraselenolate Complex from Methylmercury in Seabirds-Implications for the Hg-Se Antagonism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1515-1526. [PMID: 33476140 DOI: 10.1021/acs.est.0c06269] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In vivo and in vitro evidence for detoxification of methylmercury (MeHg) as insoluble mercury selenide (HgSe) underlies the central paradigm that mercury exposure is not or little hazardous when tissue Se is in molar excess (Se:Hg > 1). However, this hypothesis overlooks the binding of Hg to selenoproteins, which lowers the amount of bioavailable Se that acts as a detoxification reservoir for MeHg, thereby underestimating the toxicity of mercury. This question was addressed by determining the chemical forms of Hg in various tissues of giant petrels Macronectes spp. using a combination of high energy-resolution X-ray absorption near edge structure and extended X-ray absorption fine structure spectroscopy, and transmission electron microscopy coupled to elemental mapping. Three main Hg species were identified, a MeHg-cysteinate complex, a four-coordinate selenocysteinate complex (Hg(Sec)4), and a HgSe precipitate, together with a minor dicysteinate complex Hg(Cys)2. The amount of HgSe decreases in the order liver > kidneys > brain = muscle, and the amount of Hg(Sec)4 in the order muscle > kidneys > brain > liver. On the basis of biochemical considerations and structural modeling, we hypothesize that Hg(Sec)4 is bound to the carboxy-terminus domain of selenoprotein P (SelP) which contains 12 Sec residues. Structural flexibility allows SelP to form multinuclear Hgx(Se,Sec)y complexes, which can be biomineralized to HgSe by protein self-assembly. Because Hg(Sec)4 has a Se:Hg molar ratio of 4:1, this species severely depletes the stock of bioavailable Se for selenoprotein synthesis and activity to one μg Se/g dry wet in the muscle of several birds. This concentration is still relatively high because selenium is naturally abundant in seawater, therefore it probably does not fall below the metabolic need for essential selenium. However, this study shows that this may not be the case for terrestrial animals, and that muscle may be the first tissue potentially injured by Hg toxicity.
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Affiliation(s)
- Alain Manceau
- Université Grenoble Alpes, CNRS, ISTerre, 38000 Grenoble, France
| | - Anne-Claire Gaillot
- Université Nantes, CNRS, Institut des Matériaux Jean Rouxel, IMN, 44000 Nantes, France
| | - Pieter Glatzel
- European Synchrotron Radiation Facility (ESRF), 71 Rue des Martyrs, 38000 Grenoble, France
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé (CEBC), CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Paco Bustamante
- La Rochelle Université, CNRS, Littoral Environnement et Sociétés (LIENSs), 17000, La Rochelle, France
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14
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Feng R, Wang L, Yang J, Zhao P, Zhu Y, Li Y, Yu Y, Liu H, Rensing C, Wu Z, Ni R, Zheng S. Underlying mechanisms responsible for restriction of uptake and translocation of heavy metals (metalloids) by selenium via root application in plants. JOURNAL OF HAZARDOUS MATERIALS 2021; 402:123570. [PMID: 32745877 DOI: 10.1016/j.jhazmat.2020.123570] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/11/2020] [Accepted: 07/23/2020] [Indexed: 05/07/2023]
Abstract
Since selenium (Se) was shown to be an essential element for humans in 1957, the biofortification of Se to crops via foliar spraying or soil fertilization has been performed for several decades to satisfy the daily nutritional need of humans. Appropriate doses of Se were found to counteract a number of abiotic and biotic stresses, such as exposure to heavy metals (metalloids) (HMs), via influencing the regulation of antioxidant systems, by stimulation of photosynthesis, by repair of damaged cell structures and functions, by regulating the metabolism of some substances and the rebalancing of essential elements in plant tissues. However, few concerns were paid on why and how Se could reduce the uptake of a variety of HMs. This review will mainly address the migration and transformation of HMs regulated by Se in the soil-plant system in order to present a hypothesis of why and how Se can reduce the uptake of HMs in plants. The following aspects will be examined in greater detail, including 1) how the soil characteristics influences the ability of Se to reduce the bioavailability of HMs in soils and their subsequent uptake by plants, which include soil Se speciation, pH, water regime, competing ions and microbes; 2) how the plant root system influenced by Se affects the uptake or the sequestration of HMs, such as root morphology, root iron plaques and root cell wall; 3) how Se combines with HMs and then sequesters them in plant cells; 4) how Se competes with arsenic (As) and thereby reduces As uptake in plants; 5) how Se regulates the expression of genes encoding functions involved in uptake, translocation and sequestration of HMs by Se in plants.
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Affiliation(s)
- RenWei Feng
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China.
| | - LiZhen Wang
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - JiGang Yang
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - PingPing Zhao
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - YanMing Zhu
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - YuanPing Li
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - YanShuang Yu
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Hong Liu
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Christopher Rensing
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - ZeYing Wu
- Rural Energy and Environment Agency, Ministry of Agriculture and Rural Affairs, Beijing, 100125, China
| | - RunXiang Ni
- Rural Energy and Environment Agency, Ministry of Agriculture and Rural Affairs, Beijing, 100125, China
| | - ShunAn Zheng
- Rural Energy and Environment Agency, Ministry of Agriculture and Rural Affairs, Beijing, 100125, China.
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15
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Dolgova NV, Nehzati S, MacDonald TC, Summers KL, Crawford AM, Krone PH, George GN, Pickering IJ. Disruption of selenium transport and function is a major contributor to mercury toxicity in zebrafish larvae. Metallomics 2020; 11:621-631. [PMID: 30688331 DOI: 10.1039/c8mt00315g] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mercury is one of the most toxic elements threatening the biosphere, with levels steadily rising due to both natural and human activities. Selenium is an essential micronutrient, required for normal development and functioning of many organisms. While selenium is known to counteract mercury's toxicity under some conditions, to date information about the mercury-selenium relationship is fragmented and often controversial. As part of a systematic study of mercury and selenium interactions, zebrafish (Danio rerio) larvae (a model verterbrate) were exposed to methylmercury chloride or mercuric chloride. The influence of pre- and post-treatment of selenomethionine on the level and distribution of mercury and selenium in the brain and eye sections, as well as on toxicity, were examined. Selenomethionine treatment decreased the amount of maternally transfered mercury in the larval brain. Selenomethionine treatment prior to exposure to mercuric chloride increased both mercury and selenium levels in the brain but decreased their toxic effects. Conversely, methylmercury levels were not changed as a result of selenium pre-treatment, while toxicity was increased. Strikingly, both forms of mercury severely disrupted selenium metabolism, not only by depleting selenium levels due to formation of Hg-Se complexes, but also by blocking selenium transport into and out of tissues, suggesting that restoring normal selenium levels by treating the organism with selenium after mercury exposure may not be possible. Disruption of selenium metabolism by mercury may lead to disruption in function of selenoproteins. Indeed, the production of thyroid hormones by selenoprotein deiodinases was found to be severely impaired as a result of mercury exposure, with selenomethionine not always being a suitable source of selenium to restore thyroid hormone levels.
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Affiliation(s)
- Natalia V Dolgova
- Molecular and Environment Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
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16
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James AK, Nehzati S, Dolgova NV, Sokaras D, Kroll T, Eto K, O'Donoghue JL, Watson GE, Myers GJ, Krone PH, Pickering IJ, George GN. Rethinking the Minamata Tragedy: What Mercury Species Was Really Responsible? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2726-2733. [PMID: 31951385 DOI: 10.1021/acs.est.9b06253] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Industrial release of mercury into the local Minamata environment with consequent poisoning of local communities through contaminated fish and shellfish consumption is considered the classic case of environmental mercury poisoning. However, the mercury species in the factory effluent has proved controversial, originally suggested as inorganic, and more recently as methylmercury species. We used newly available methods to re-examine the cerebellum of historic Cat 717, which was fed factory effluent mixed with food to confirm the source. Synchrotron high-energy-resolution fluorescence detection-X-ray absorption spectroscopy revealed sulfur-bound organometallic mercury with a minor β-HgS phase. Density functional theory indicated energetic preference for α-mercuri-acetaldehyde as a waste product of aldehyde production. The consequences of this alternative species in the "classic" mercury poisoning should be re-evaluated.
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Affiliation(s)
- Ashley K James
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Susan Nehzati
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V Dolgova
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Komyo Eto
- National Institute for Minamata Disease, Ministry of the Environment,, Kumamoto 867-0008, Japan
| | - John L O'Donoghue
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
| | - Gene E Watson
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
- Eastman Institute for Oral Health, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
| | - Gary J Myers
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
- Departments of Neurology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
| | - Patrick H Krone
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
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17
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Ashley-Martin J, Dodds L, Arbuckle TE, Lanphear B, Muckle G, Bouchard MF, Fisher M, Asztalos E, Foster W, Kuhle S. Blood metal levels and early childhood anthropometric measures in a cohort of Canadian children. ENVIRONMENTAL RESEARCH 2019; 179:108736. [PMID: 31541908 DOI: 10.1016/j.envres.2019.108736] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/03/2019] [Accepted: 09/07/2019] [Indexed: 05/18/2023]
Abstract
Fetal exposure to some toxic metals has been associated with reduced fetal growth, but the impact of contemporary, low-level metals on anthropometric measures in childhood is not well understood. Our primary objective was to quantify associations between childhood levels of toxic metals and concurrently measured body mass index (BMI) in a population of Canadian preschool-aged children. We collected biomonitoring data and anthropometric measures on 480 children between the ages of two and five years in the Maternal-Infant Research on Environmental Chemicals (MIREC) Child Development Plus study. Concentrations of four toxic metals (lead, arsenic, cadmium, and mercury) were measured in whole blood collected from pregnant women and their children. Blood levels of key essential elements were also measured in children. Children's weight, height, and BMI z-scores were calculated using the World Health Organization growth standards. We used a series of linear regression models, adjusted for potential parental confounders, concurrently measured metals and elements, and prenatal blood metal levels, to evaluate associations between tertiles of each toxic metal and anthropometric measures. We tested for effect modification by sex. Of the 480 children, 449 (94%) were singleton births and had complete biomonitoring and anthropometric data. The majority of children had detectable concentrations of metals. In the adjusted models, girls with blood lead concentrations in the highest tertile (>0.82 μg/dL) had, on average, 0.26 (95% Cl: -0.55, 0.03) lower BMI z-scores than those in the referent category. In contrast, boys with lead levels in the highest tertile had, on average, 0.14 higher BMI z-scores (95% Cl: -0.14, 0.41) (p-value heterogeneity = 0.04). In this population of Canadian preschool-aged children with low-level blood lead concentrations, we observed effect modification by sex in the association between Pb and BMI but no statistically significant associations in the sex-specific strata. Child blood levels of As, Cd, and Hg were not associated with childhood BMI, weight, or height in boys or girls.
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Affiliation(s)
| | - Linda Dodds
- Perinatal Epidemiology Research Unit, Dalhousie University, Halifax, NS, Canada
| | - Tye E Arbuckle
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | | | - Gina Muckle
- Laval University and Quebec CHU Research Center, Quebec City, QC, Canada
| | | | - Mandy Fisher
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | | | | | - Stefan Kuhle
- Perinatal Epidemiology Research Unit, Dalhousie University, Halifax, NS, Canada.
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18
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Zhang Z, Yuan L, Qi S, Yin X. The threshold effect between the soil bioavailable molar Se:Cd ratio and the accumulation of Cd in corn (Zea mays L.) from natural Se-Cd rich soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 688:1228-1235. [PMID: 31726553 DOI: 10.1016/j.scitotenv.2019.06.331] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/22/2019] [Accepted: 06/21/2019] [Indexed: 05/10/2023]
Abstract
There is little available information about the important interactions between selenium and cadmium (Se-Cd) in crops grown on natural Se-Cd rich soils. We investigated their interactive effects on the translocation and uptake of Se and Cd from soils to crops. Corn (Zea mays L.) roots, stems, leaves, and grains, and their corresponding rhizosphere soils were collected from naturally Se-Cd rich areas in Wumeng Mountain, Guizhou, China. The Se and Cd levels were determined in the soils, roots, stems, leaves, and grains. Soil bioavailable Se and Cd were also determined. The low soil bioavailable molar ratios for Se and Cd (Se:Cd) (≤0.7) improved Cd accumulation in the plants. However, relatively high Se:Cd molar ratios (>0.7) in the soils prevented Cd from entering the plants, but the effect of the soil Se:Cd on Se accumulation in corn was not significant. The strong anion exchange-high performance liquid chromatography-inductively coupled plasma mass spectroscopy (SAX-HPLC-ICP-MS) chromatograms showed that Se-Cd complexes occurred in the leaves, which likely indicated that direct interactions between Se and Cd happened there. The results suggested that thresholds for soil bioavailable Se:Cd molar ratios played a role in the interaction between Se and Cd in corn under natural conditions.
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Affiliation(s)
- Zezhou Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Linxi Yuan
- Agricultural College of Yangzhou University, Yangzhou, China; Jiangsu Bio-Engineering Research Centre of Selenium, Suzhou, China.
| | - Shihua Qi
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Xuebin Yin
- Key Laboratory of Functional Agriculture, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, China
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19
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Pereira P, Korbas M, Pereira V, Cappello T, Maisano M, Canário J, Almeida A, Pacheco M. A multidimensional concept for mercury neuronal and sensory toxicity in fish - From toxicokinetics and biochemistry to morphometry and behavior. Biochim Biophys Acta Gen Subj 2019; 1863:129298. [PMID: 30768958 DOI: 10.1016/j.bbagen.2019.01.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 01/16/2019] [Accepted: 01/30/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Neuronal and sensory toxicity of mercury (Hg) compounds has been largely investigated in humans/mammals with a focus on public health, while research in fish is less prolific and dispersed by different species. Well-established premises for mammals have been governing fish research, but some contradictory findings suggest that knowledge translation between these animal groups needs prudence [e.g. the relative higher neurotoxicity of methylmercury (MeHg) vs. inorganic Hg (iHg)]. Biochemical/physiological differences between the groups (e.g. higher brain regeneration in fish) may determine distinct patterns. This review undertakes the challenge of identifying sensitive cellular targets, Hg-driven biochemical/physiological vulnerabilities in fish, while discriminating specificities for Hg forms. SCOPE OF REVIEW A functional neuroanatomical perspective was conceived, comprising: (i) Hg occurrence in the aquatic environment; (ii) toxicokinetics on central nervous system (CNS)/sensory organs; (iii) effects on neurotransmission; (iv) biochemical/physiological effects on CNS/sensory organs; (v) morpho-structural changes on CNS/sensory organs; (vi) behavioral effects. The literature was also analyzed to generate a multidimensional conceptualization translated into a Rubik's Cube where key factors/processes were proposed. MAJOR CONCLUSIONS Hg neurosensory toxicity was unequivocally demonstrated. Some correspondence with toxicity mechanisms described for mammals (mainly at biochemical level) was identified. Although the research has been dispersed by numerous fish species, 29 key factors/processes were pinpointed. GENERAL SIGNIFICANCE Future trends were identified and translated into 25 factors/processes to be addressed. Unveiling the neurosensory toxicity of Hg in fish has a major motivation of protecting ichtyopopulations and ecosystems, but can also provide fundamental knowledge to the field of human neurodevelopment.
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Affiliation(s)
- Patrícia Pereira
- Department of Biology and CESAM, University of Aveiro, Aveiro 3810-193, Portugal
| | - Malgorzata Korbas
- Science Division, Canadian Light Source Inc., Saskatoon, Canada; Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Canada
| | - Vitória Pereira
- Department of Biology and CESAM, University of Aveiro, Aveiro 3810-193, Portugal
| | - Tiziana Cappello
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d'Alcontres 31, Messina 98166, Italy
| | - Maria Maisano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d'Alcontres 31, Messina 98166, Italy
| | - João Canário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa 1049-001, Portugal
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), University of Minho, Campus of Gualtar, Braga 4750-057, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga, Portugal
| | - Mário Pacheco
- Department of Biology and CESAM, University of Aveiro, Aveiro 3810-193, Portugal.
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20
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Jamwal A, Saibu Y, MacDonald TC, George GN, Niyogi S. The effects of dietary selenomethionine on tissue-specific accumulation and toxicity of dietary arsenite in rainbow trout (Oncorhynchus mykiss) during chronic exposure. Metallomics 2019; 11:643-655. [DOI: 10.1039/c8mt00309b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selenomethionine facilitated arsenic deposition in the brain and likely in other tissues, possibly via bio-complexation. Elevated dietary selenomethionine can increase the tissue-specific accumulation and toxicity of As3+ in fish during chronic dietary exposure.
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Affiliation(s)
- Ankur Jamwal
- Department of Biology
- University of Saskatchewan
- Saskatoon
- Canada
| | - Yusuf Saibu
- Toxicology Centre
- University of Saskatchewan
- Saskatoon
- Canada
| | | | - Graham N. George
- Toxicology Centre
- University of Saskatchewan
- Saskatoon
- Canada
- Department of Geology
| | - Som Niyogi
- Department of Biology
- University of Saskatchewan
- Saskatoon
- Canada
- Toxicology Centre
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21
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Gajdosechova Z, Mester Z, Feldmann J, Krupp EM. The role of selenium in mercury toxicity – Current analytical techniques and future trends in analysis of selenium and mercury interactions in biological matrices. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2017.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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22
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Wang X, Wang WX. Selenium induces the demethylation of mercury in marine fish. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 231:1543-1551. [PMID: 28928020 DOI: 10.1016/j.envpol.2017.09.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/06/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
The antagonistic effect of selenium (Se) on mercury (Hg) toxicity has been known for decades. Earlier studies mainly focused on Hg-Se interaction based on biokinetics and bioaccumulation, but the influences of Se on in vivo biotransformation of methylmercury (MeHg) have not been well understood. We conducted a 42-day exposure study to investigate the dynamic changes of MeHg and its primary degradation product - inorganic mercury (IHg) - in different organs of black seabream (Acanthopagrus schlegeli) exposed to different dietary Se levels. A physiologically based pharmacokinetic (PBPK) model was then developed to describe the biotransformation and disposition of MeHg under the influence of Se. Our results demonstrated that Se significantly increased the transformation from MeHg into IHg, thereby decreasing the accumulation of MeHg. The simulation further showed that the intestine was the major site for demethylation, with an estimated rate 1.5-fold higher in high Se treatment than in low Se treatment. However, the hepatic demethylation rate was extremely low and comparable between the two treatments (0.012-0.015 d-1). These results strongly suggested that the intestine instead of the commonly assumed liver was the major site for Hg-Se interaction. Furthermore, Se did not show significant influences on the distribution and elimination of MeHg, but promoted the uptake and elimination of the generated IHg from demethylation. Therefore, Se-induced demethylation especially in the intestine played an important role in mitigating the MeHg accumulation. This study provided new sight to elucidate the Hg-Se interaction in fish.
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Affiliation(s)
- Xun Wang
- Division of Life Science, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong; Marine Environmental Laboratory, HKUST Shenzhen Research Institute, Shenzhen 518057, China
| | - Wen-Xiong Wang
- Division of Life Science, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong; Marine Environmental Laboratory, HKUST Shenzhen Research Institute, Shenzhen 518057, China.
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MacDonald TC, Sylvain NJ, James AK, Pickering IJ, Krone PH, George GN. Effects of inorganic mercury on the olfactory pits of zebrafish larvae. Metallomics 2017; 8:514-7. [PMID: 27108745 DOI: 10.1039/c6mt00031b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Mercury compounds are highly toxic; due to the rising levels of mercury pollution, both human and environmental exposure to mercury are increasing. Occupational exposure to inhaled mercury can be high, causing adverse effects not only in the lungs, but in the olfactory system as well. Olfaction plays a critical role in the survival of fish and other vertebrates, and impaired olfaction can substantially impact human quality of life. We present a study of the effects of mercury exposure in the olfactory pits of zebrafish larvae using a combination of X-ray fluorescence imaging and immunohistochemistry. We show that mercury accumulates in the sensory cells of the olfactory pits and also that it may also damage primary neurons, such as those that innervate olfactory pits.
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Affiliation(s)
- Tracy C MacDonald
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada. and Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada and Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Nicole J Sylvain
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Ashley K James
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada. and Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada and Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Ingrid J Pickering
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada. and Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada and Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
| | - Patrick H Krone
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada and Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Graham N George
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada. and Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada and Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
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Weekley CM, Kenkel I, Lippert R, Wei S, Lieb D, Cranwell T, Wedding JL, Zillmann AS, Rohr R, Filipovic MR, Ivanović-Burmazović I, Harris HH. Cellular Fates of Manganese(II) Pentaazamacrocyclic Superoxide Dismutase (SOD) Mimetics: Fluorescently Labeled MnSOD Mimetics, X-ray Absorption Spectroscopy, and X-ray Fluorescence Microscopy Studies. Inorg Chem 2017; 56:6076-6093. [DOI: 10.1021/acs.inorgchem.6b03073] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Claire M. Weekley
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Isabell Kenkel
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Rainer Lippert
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Shengwei Wei
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Dominik Lieb
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Tiffanny Cranwell
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Jason L. Wedding
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Annika S. Zillmann
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Robin Rohr
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Milos R. Filipovic
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Ivana Ivanović-Burmazović
- Department of Chemistry
and Pharmacy, University of Erlangen−Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Hugh H. Harris
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
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Selenium Speciation in the Fountain Creek Watershed (Colorado, USA) Correlates with Water Hardness, Ca and Mg Levels. Molecules 2017; 22:molecules22050708. [PMID: 28468296 PMCID: PMC6154685 DOI: 10.3390/molecules22050708] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 04/14/2017] [Accepted: 04/19/2017] [Indexed: 01/26/2023] Open
Abstract
The environmental levels of selenium (Se) are regulated and strictly enforced by the Environmental Protection Agency (EPA) because of the toxicity that Se can exert at high levels. However, speciation plays an important role in the overall toxicity of Se, and only when speciation analysis has been conducted will a detailed understanding of the system be possible. In the following, we carried out the speciation analysis of the creek waters in three of the main tributaries—Upper Fountain Creek, Monument Creek and Lower Fountain Creek—located in the Fountain Creek Watershed (Colorado, USA). There are statistically significant differences between the Se, Ca and Mg, levels in each of the tributaries and seasonal swings in Se, Ca and Mg levels have been observed. There are also statistically significant differences between the Se levels when grouped by Pierre Shale type. These factors are considered when determining the forms of Se present and analyzing their chemistry using the reported thermodynamic relationships considering Ca2+, Mg2+, SeO42−, SeO32− and carbonates. This analysis demonstrated that the correlation between Se and water hardness can be explained in terms of formation of soluble CaSeO4. The speciation analysis demonstrated that for the Fountain Creek waters, the Ca2+ ion may be mainly responsible for the observed correlation with the Se level. Considering that the Mg2+ level is also correlating linearly with the Se levels it is important to recognize that without Mg2+ the Ca2+ would be significantly reduced. The major role of Mg2+ is thus to raise the Ca2+ levels despite the equilibria with carbonate and other anions that would otherwise decrease Ca2+ levels.
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26
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Reyes ES, Aristizabal Henao JJ, Kornobis KM, Hanning RM, Majowicz SE, Liber K, Stark KD, Low G, Swanson HK, Laird BD. Associations between omega-3 fatty acids, selenium content, and mercury levels in wild-harvested fish from the Dehcho Region, Northwest Territories, Canada. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 80:18-31. [PMID: 27905863 DOI: 10.1080/15287394.2016.1230916] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 08/28/2016] [Indexed: 06/06/2023]
Abstract
To better understand the risks and benefits of eating wild-harvested fish from the Northwest Territories, Canada, levels of total mercury (HgT) and selenium (Se) and composition of omega-3 fatty acid (n-3 FA) were measured in muscle tissue of fish harvested from lakes in the Dehcho Region, Northwest Territories, Canada. Average HgT levels ranged from 0.057 mg/kg (cisco) to 0.551 mg/kg (northern pike), while average n-3 FA concentrations ranged from 101 mg/100 g (burbot) to 1,689 mg/100 g (lake trout). In contrast to HgT and n-3 FA, mean Se concentrations were relatively similar among species. Consequently, species such as lake whitefish, cisco, and longnose sucker displayed the highest nutrient levels relative to HgT content. Levels of HgT tended to increase with fish size, while Se and n-3 FA levels were typically not associated with fork length or fish weight. Interestingly, HgT concentration was occasionally inversely related to tissue nutrient content. Significant negative correlations were observed between Hg and n-3 FA for lake trout, northern pike, and walleye. There were also significant negative correlations between Hg and Se noted for lake whitefish, cisco, and northern pike. Samples with the highest nutritional content displayed, on occasion, lower levels of HgT. This study provides valuable information for the design of probabilistic models capable of refining public health messaging related to minimizing Hg risks and maximizing nutrient levels in wild-harvested fish in the Canadian subarctic.
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Affiliation(s)
- Ellen S Reyes
- a School of Public Health and Health Systems, University of Waterloo , Waterloo , Canada
| | | | | | - Rhona M Hanning
- a School of Public Health and Health Systems, University of Waterloo , Waterloo , Canada
| | - Shannon E Majowicz
- a School of Public Health and Health Systems, University of Waterloo , Waterloo , Canada
| | - Karsten Liber
- d Toxicology Centre, University of Saskatchewan , Saskatoon , Saskatchewan , Canada
| | - Ken D Stark
- b Department of Kinesiology , University of Waterloo , Waterloo , Canada
| | - George Low
- e Dehcho Aboriginal Aquatic Resources and Ocean Management , Hay River, Northwest Territories , Canada
| | - Heidi K Swanson
- c Department of Biology , University of Waterloo , Waterloo , Canada
| | - Brian D Laird
- a School of Public Health and Health Systems, University of Waterloo , Waterloo , Canada
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27
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In vivo formation of natural HgSe nanoparticles in the liver and brain of pilot whales. Sci Rep 2016; 6:34361. [PMID: 27678068 PMCID: PMC5039623 DOI: 10.1038/srep34361] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/07/2016] [Indexed: 12/23/2022] Open
Abstract
To understand the biochemistry of methylmercury (MeHg) that leads to the formation of mercury-selenium (Hg-Se) clusters is a long outstanding challenge that promises to deepen our knowledge of MeHg detoxification and the role Se plays in this process. Here, we show that mercury selenide (HgSe) nanoparticles in the liver and brain of long-finned pilot whales are attached to Se-rich structures and possibly act as a nucleation point for the formation of large Se-Hg clusters, which can grow with age to over 5 μm in size. The detoxification mechanism is fully developed from the early age of the animals, with particulate Hg found already in juvenile tissues. As a consequence of MeHg detoxification, Se-methionine, the selenium pool in the system is depleted in the efforts to maintain essential levels of Se-cysteine. This study provides evidence of so far unreported depletion of the bioavailable Se pool, a plausible driving mechanism of demonstrated neurotoxic effects of MeHg in the organism affected by its high dietary intake.
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28
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Dolgova NV, Hackett MJ, MacDonald TC, Nehzati S, James AK, Krone PH, George GN, Pickering IJ. Distribution of selenium in zebrafish larvae after exposure to organic and inorganic selenium forms. Metallomics 2016; 8:305-12. [DOI: 10.1039/c5mt00279f] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selenium is found to be highly concentrated in zebrafish pigment (melanin) containing tissues especially for the organic selenium treatments, with lower concentrations in eye lens, yolk sac and heart.
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Affiliation(s)
- N. V. Dolgova
- Molecular and Environmental Science Research Group
- Department of Geological Sciences
- University of Saskatchewan
- Saskatoon, Canada
| | - M. J. Hackett
- Molecular and Environmental Science Research Group
- Department of Geological Sciences
- University of Saskatchewan
- Saskatoon, Canada
| | - T. C. MacDonald
- Molecular and Environmental Science Research Group
- Department of Geological Sciences
- University of Saskatchewan
- Saskatoon, Canada
- Toxicology Centre
| | - S. Nehzati
- Molecular and Environmental Science Research Group
- Department of Geological Sciences
- University of Saskatchewan
- Saskatoon, Canada
| | - A. K. James
- Molecular and Environmental Science Research Group
- Department of Geological Sciences
- University of Saskatchewan
- Saskatoon, Canada
- Toxicology Centre
| | - P. H. Krone
- Toxicology Centre
- University of Saskatchewan
- Saskatoon, Canada
- Department of Anatomy and Cell Biology
- University of Saskatchewan
| | - G. N. George
- Molecular and Environmental Science Research Group
- Department of Geological Sciences
- University of Saskatchewan
- Saskatoon, Canada
- Toxicology Centre
| | - I. J. Pickering
- Molecular and Environmental Science Research Group
- Department of Geological Sciences
- University of Saskatchewan
- Saskatoon, Canada
- Toxicology Centre
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