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Xiang Y, Guo Y, Liu G, Liu Y, Song M, Shi J, Hu L, Yin Y, Cai Y, Jiang G. Particle-Bound Hg(II) is Available for Microbial Uptake as Revealed by a Whole-Cell Biosensor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:6754-6764. [PMID: 35502862 DOI: 10.1021/acs.est.1c08946] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Particle-bound mercury (HgP), ubiquitously present in aquatic environments, can be methylated into highly toxic methylmercury, but it remains challenging to assess its bioavailability. In this study, we developed anEscherichia coli-based whole-cell biosensor to probe the microbial uptake of inorganic Hg(II) and assess the bioavailability of HgP sorbed on natural and model particles. This biosensor can quantitatively distinguish the contribution of dissolved Hg(II) and HgP to intracellular Hg. Results showed that the microbial uptake of HgP was ubiquitous in the environment, as evidenced by the bioavailability of sorbed-Hg(II) onto particulate matter and model particles (Fe2O3, Fe3O4, Al2O3, and SiO2). In both oxic and anoxic environments, HgP was an important Hg(II) source for microbial uptake, with enhanced bioavailability under anoxic conditions. The composition of particles significantly affected the microbial uptake of HgP, with higher bioavailability being observed for Fe2O3 and lower for Al2O3 particles. The bioavailability of HgP varied also with the size of particles. In addition, coating with humic substances and model organic compound (cysteine) on Fe2O3 particles decreased the bioavailability of HgP. Overall, our findings highlight the role of HgP in Hg biogeochemical cycling and shed light on the enhanced Hg-methylation in settling particles and sediments in aquatic environments.
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Affiliation(s)
- Yuping Xiang
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingying Guo
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangliang Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Yanwei Liu
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Maoyong Song
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jianbo Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ligang Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Institute of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
| | - Yong Cai
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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2
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Ahmad H, Koo BH, Khan RA. Preconcentration and determination of trace Hg(ii) using ultrasound-assisted dispersive solid phase microextraction. RSC Adv 2022; 12:53-61. [PMID: 35424482 PMCID: PMC8978612 DOI: 10.1039/d1ra07898d] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/13/2021] [Indexed: 11/21/2022] Open
Abstract
Defect rich molybdenum disulfide (MoS2) nanosheets were hydrothermally synthesized and their potential for ultrasound assisted dispersive solid phase microextraction of trace Hg(ii) ions was assessed. Ultrasonic dispersion allows the MoS2 nanosheets to chelate rapidly and evenly with Hg(ii) ions and results in improving the precision and minimizing the extraction time. The multiple defect rich surface was characterized by X-ray diffraction and high-resolution transmission electron microscopy. The surface charge of intrinsically sulfur rich MoS2 nanosheets and their elemental composition was characterized by zeta potential measurements, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. The cracks and holes on the basal planes of MoS2 led to diffusion of the Hg(ii) ions into the interior channels. Inner-sphere chelation along with outer-sphere electrostatic interaction were the proposed mechanism for the Hg(ii) adsorption onto the MoS2 surface. The experimental data showed good selectivity of MoS2 nanosheets towards Hg(ii) adsorption. The systematic and constant errors of the proposed method were ruled out by the analysis of the Standard Reference Material (>95% recovery with <5% RSD). The Student's t-test values for the analyzed Standard Reference Material were found to be less than the critical Student's t value at 95% confidence level. The limit of detection (3S) was found to be 0.01 ng mL−1. The MoS2 nanosheets were successfully employed for the analysis of Hg(ii) in environmental water samples. Hg(ii) ion adsorption onto an MoS2 surface.![]()
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Affiliation(s)
- Hilal Ahmad
- Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Bon Heun Koo
- School of Materials Science and Engineering, Changwon National University, Changwon 51140, Gyeongnam, South Korea
| | - Rais Ahmad Khan
- Department of Chemistry, College of Science, King Saud University, Riyadh-11451, Kingdom of Saudi Arabia
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3
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Safari N, Ghanemi K, Buazar F. Selenium functionalized magnetic nanocomposite as an effective mercury (II) ion scavenger from environmental water and industrial wastewater samples. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 276:111263. [PMID: 32889499 DOI: 10.1016/j.jenvman.2020.111263] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/23/2020] [Accepted: 08/17/2020] [Indexed: 05/12/2023]
Abstract
A novel core-shell magnetic-selenium nanocomposite (Fe3O4@SiO2@Se) was synthesized for fast and effective removal of Hg (II) ions from various industrial and environmental water samples. The composition, property, and structure of Fe3O4@SiO2@Se were characterized by spectral and microscopic techniques. The key parameters affecting the removal were evaluated and optimized. The concentration of residual Hg (II) ions in the solution was measured using a cold vapor atomic absorption spectrometer. At pH = 3.0, Fe3O4@SiO2@Se was capable to remove Hg (II) ions ranged from 100 μg L-1 to 10 mg L-1 within 20 min with the efficiency of approximately 99% in a way that residual concentration levels matched international standards. This level of removal efficiency was well maintained up to salinity of 25 g L-1. Kinetic investigations revealed compliance with a second-order kinetic model. The linear regression coefficient suggested the adsorption of Hg (II) ions by the adsorbent followed the Langmuir isotherm model (R2 > 0.997). The maximum capacity of the adsorbent obtained through investigating the isotherms was 70.42 mg g-1. The Fe3O4@SiO2@Se adsorbent effectively removed the Hg (II) ions spiked to different samples, including tap water, river water, seawater, and industrial wastewater. Therefore, this nano-adsorbent can be used as a good alternative for Hg (II) removal, in practical applications.
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Affiliation(s)
- Nima Safari
- Department of Marine Chemistry, Faculty of Marine Science, Khorramshahr University of Marine Science and Technology, P.O. BOX 669, Khorramshahr, Iran
| | - Kamal Ghanemi
- Department of Marine Chemistry, Faculty of Marine Science, Khorramshahr University of Marine Science and Technology, P.O. BOX 669, Khorramshahr, Iran.
| | - Foad Buazar
- Department of Marine Chemistry, Faculty of Marine Science, Khorramshahr University of Marine Science and Technology, P.O. BOX 669, Khorramshahr, Iran
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4
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Kelly CA, Rudd JWM. Transport of mercury on the finest particles results in high sediment concentrations in the absence of significant ongoing sources. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 637-638:1471-1479. [PMID: 29801240 DOI: 10.1016/j.scitotenv.2018.04.234] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
The mercury contaminated upper Penobscot Estuary in Maine provided a unique opportunity to rigorously examine the effect of sediment type and particle size on mercury concentrations in sediments, and to explain why sediments at different locations in the estuary had different mercury concentrations. This is because the Penobscot Estuary contains a large, well-mixed pool of mobile sediments of many different types (muds, sand, gravel, wood chips), which are the source of material for the permanently deposited surface sediments. Despite this mixing, average surface sediment mercury concentrations were very different in different locations, ranging from 238 ng/gdw to 1032 ng/gdw in the 11 subareas studied. Average total mercury concentrations were highly related to the type of sediment (wood chips > muds > sands) regardless of location in the estuary. The characteristics in both mobile and surface sediments that were positively related to total mercury concentrations were % organic matter (measured as loss on ignition) and %fines (measured usually as <62.5 μ). Also, in a subset of samples it was shown that mercury was positively associated only with the very finest (<44 μ) particles. Thus, side embayments of the estuary such as the Orland River and Mendall Marsh, which experience lower velocity currents and so accumulate more fine particles, tended to be much higher in mercury concentrations. This knowledge will be important in managing remediation of this system, as fine particles can be the most difficult to trap or to retain if dredging is employed. Methyl mercury was well correlated with total mercury and so its distribution would also be affected by transport characteristics. This was the case even in the mobile sediments, which were more oxic and not expected to provide a good habitat for methylation.
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Affiliation(s)
- Carol A Kelly
- R&K Research Inc., 675 Mount Belcher Heights, Salt Spring Island, BC V8K 2J3, Canada.
| | - John W M Rudd
- R&K Research Inc., 675 Mount Belcher Heights, Salt Spring Island, BC V8K 2J3, Canada
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5
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Review on the latest developments in modified vanadium-titanium-based SCR catalysts. CHINESE JOURNAL OF CATALYSIS 2018. [DOI: 10.1016/s1872-2067(18)63090-6] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Olsen M, Schaanning MT, Braaten HFV, Eek E, Moy FE, Lydersen E. The influence of permanently submerged macrophytes on sediment mercury distribution, mobility and methylation potential in a brackish Norwegian fjord. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 610-611:1364-1374. [PMID: 28851156 DOI: 10.1016/j.scitotenv.2017.08.136] [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: 04/13/2017] [Revised: 08/06/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
Macrophytes are shown to affect the microbial activity in different aqueous environments, with an altering of the sediment cycling of mercury (Hg) as a potential effect. Here, we investigated how a meadow with permanently submerged macrophytes in a contaminated brackish fjord in southern Norway influenced the conditions for sulfate reducing microbial activity, the methyl-Hg (MeHg) production and the availability of MeHg. Historically discharged Hg from a chlor-alkali plant (60-80tons, 1947-1987) was evident through high Hg concentrations (491mgTot-Hgkg-1, 268μgMeHgkg-1) in intermediate sediment depths (10-20cm) outside of the meadow, with reduced concentrations within the meadow. Natural recovery of the fjord was revealed by lower sediment surface concentrations (1.9-15.5mgTot-Hgkg-1, 1.3-3.2μgMeHgkg-1). Within the meadow, vertical gradients of sediment hydrogen sulfide (H2S) Eh and pH suggested microbial sulfate reduction in 2-5cm depths, coinciding with peak values of relative MeHg levels (0.5% MeHg). We assume that MeHg production rates was stimulated by the supply and availability of organic carbon, microbial activity and a sulfide oxidizing agent (e.g. O2) within the rhizosphere. Following this, % MeHg in sediment (0-5cm) within the meadow was approximately 10× higher compared to outside the meadow. Further, enhanced availability of MeHg within the meadow was demonstrated by significantly higher fluxes (p<0.01) from sediment to overlying water (0.1-0.6ngm-2d-1) compared to sediment without macrophytes (0.02-0.2ngm-2d-1). Considering the productivity and species richness typical for such habitats, submerged macrophyte meadows located within legacy Hg contaminated sediment sites may constitute important entry points for MeHg into food webs.
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Affiliation(s)
- Marianne Olsen
- University College of Southeast Norway, Gullbringvegen 36, N-3800 Bø, Norway; The Norwegian Institute for Water Research, Gaustadalléen 21, N-0349 Oslo, Norway.
| | | | | | - Espen Eek
- Norwegian Geotechnical Institute, NGI, PB 3930, Ullevål Stadion, 0806 Oslo, Norway
| | - Frithjof E Moy
- Institute of Marine Research, Nye Flødevigveien 20, 4817 His, Norway
| | - Espen Lydersen
- University College of Southeast Norway, Gullbringvegen 36, N-3800 Bø, Norway
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7
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Stenzler B, Hinz A, Ruuskanen M, Poulain AJ. Ionic Strength Differentially Affects the Bioavailability of Neutral and Negatively Charged Inorganic Hg Complexes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:9653-9662. [PMID: 28701033 DOI: 10.1021/acs.est.7b01414] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mercury (Hg) bioavailability to bacteria in marine systems is the first step toward its bioamplification in food webs. These systems exhibit high salinity and ionic strength that will both alter Hg speciation and properties of the bacteria cell walls. The role of Hg speciation on Hg bioavailability in marine systems has not been teased apart from that of ionic strength on cell wall properties, however. We developed and optimized a whole-cell Hg bioreporter capable of functioning under aerobic and anaerobic conditions and exhibiting no physiological limitations of signal production to changes in ionic strength. We show that ionic strength controls the bioavailability of Hg species, regardless of their charge, possibly by altering properties of the bacterial cell wall. The unexpected anaerobic bioavailability of negatively charged halocomplexes may help explain Hg methylation in marine systems such as the oxygen-deficient zone in the oceanic water column, sea ice or polar snow.
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Affiliation(s)
- Benjamin Stenzler
- Biology Department, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Aaron Hinz
- Biology Department, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Matti Ruuskanen
- Biology Department, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Alexandre J Poulain
- Biology Department, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
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8
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Wang J, Wang Y, Dong Y, Lu L, Li Q, Wang Z, Zhang Y. Modified Capillary Electrophoresis for Highly Sensitive and Selective Detection of Hg2+ in Natural Water. J CHIN CHEM SOC-TAIP 2016. [DOI: 10.1002/jccs.201500521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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9
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Moreno CE, Fjeld E, Lydersen E. The effects of wildfire on mercury and stable isotopes (δ(15)N, δ(13)C) in water and biota of small boreal, acidic lakes in southern Norway. ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:178. [PMID: 26896966 DOI: 10.1007/s10661-016-5148-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 02/01/2016] [Indexed: 05/21/2023]
Abstract
Effects of wildfire on main water chemistry and mercury (Hg) in water and biota were studied during the first 4 post-fire years. After severe water chemical conditions during hydrological events a few months following the wildfire, the major water chemical parameters were close to pre-fire conditions 4 years after the fire. Concentrations of total Hg and methyl Hg in the surface water 4 years after the fire ranged between 1.17-2.63 ng L(-1) and 0.053-0.188 ng L(-1), respectively. Both variables were positive and strongly correlated with total organic carbon (TOC), TOC-related variables (color, UV absorbance), total phosphorous, and total iron. In addition, MeHg was positively correlated with total nitrogen and chlorophyll-a. The concurrence of increased concentrations of nutrients and chlorophyll-a in the lakes, the more enriched δ(15)N-signatures and higher Hg levels in fish 2 years after the fire, might be a result of the wildfire. However, natural factors as year-to-year variations in thermocline depth and suboxic status in the lakes make it difficult to draw any strong conclusions about wildfire effects on Hg in the biota from our investigated lakes.
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Affiliation(s)
- Clara E Moreno
- Department of Environmental and Health Studies, University College of Southeast Norway, Hallvard Eikas Plass 1, No-3800, Bø i Telemark, Norway.
| | - Eirik Fjeld
- Norwegian Institute for Water Research, Gaustadallén 21, No-0340, Oslo, Norway.
| | - Espen Lydersen
- Department of Environmental and Health Studies, University College of Southeast Norway, Hallvard Eikas Plass 1, No-3800, Bø i Telemark, Norway.
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10
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Wang JW, Shen YY, Dong YJ, Qin W, Zhang QP, Lu L, Zhang YG. Oxidation and adsorption of gas-phase Hg0 over a V2O5/AC catalyst. RSC Adv 2016. [DOI: 10.1039/c6ra15455g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
V2O5/AC had a high Hg0 capture capability due to the co-effects of oxidation and adsorption and O2 enhanced Hg0 oxidation.
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Affiliation(s)
- Jun-Wei Wang
- Anhui Key Laboratory of Functional Coordination Compounds
- College of Chemistry and Chemical Engineering
- Anqing Normal University
- Anqing 246011
- PR China
| | - Yuan-Yuan Shen
- Anhui Key Laboratory of Functional Coordination Compounds
- College of Chemistry and Chemical Engineering
- Anqing Normal University
- Anqing 246011
- PR China
| | - Yan-Jie Dong
- Anhui Key Laboratory of Functional Coordination Compounds
- College of Chemistry and Chemical Engineering
- Anqing Normal University
- Anqing 246011
- PR China
| | - Wei Qin
- Anhui Key Laboratory of Functional Coordination Compounds
- College of Chemistry and Chemical Engineering
- Anqing Normal University
- Anqing 246011
- PR China
| | - Qing-Ping Zhang
- Anhui Key Laboratory of Functional Coordination Compounds
- College of Chemistry and Chemical Engineering
- Anqing Normal University
- Anqing 246011
- PR China
| | - Lu Lu
- Anhui Key Laboratory of Functional Coordination Compounds
- College of Chemistry and Chemical Engineering
- Anqing Normal University
- Anqing 246011
- PR China
| | - Yuan-Guang Zhang
- Anhui Key Laboratory of Functional Coordination Compounds
- College of Chemistry and Chemical Engineering
- Anqing Normal University
- Anqing 246011
- PR China
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11
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Le Faucheur S, Campbell PGC, Fortin C, Slaveykova VI. Interactions between mercury and phytoplankton: speciation, bioavailability, and internal handling. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:1211-1224. [PMID: 24127330 DOI: 10.1002/etc.2424] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 06/11/2013] [Accepted: 10/03/2013] [Indexed: 06/02/2023]
Abstract
The present review describes and discusses key interactions between mercury (Hg) and phytoplankton to highlight the role of phytoplankton in the biogeochemical cycle of Hg and to understand direct or indirect Hg effects on phytoplankton. Phytoplankton are exposed to various Hg species in surface waters. Through Hg uptake, phytoplankton affect the concentration, speciation, and fate of Hg in aquatic systems. The mechanisms by which phytoplankton take up Hg are still not well known, but several studies have suggested that both facilitated transport and passive diffusion could be involved. Once internalized, Hg will impact several physiological processes, including photosynthesis. To counteract these negative effects, phytoplankton have developed several detoxification strategies, such as the reduction of Hg to elemental Hg or its sequestration by intracellular ligands. Based on the toxicological studies performed so far in the laboratory, Hg is unlikely to be toxic to phytoplankton when they are exposed to environmentally relevant Hg concentrations. However, this statement should be taken with caution because questions remain as to which Hg species control Hg bioavailability and about Hg uptake mechanisms. Finally, phytoplankton are primary producers, and accumulated Hg will be transferred to higher consumers. Phytoplankton are a key component in aquatic systems, and their interactions with Hg need to be further studied to fully comprehend the biogeochemical cycle of Hg and the impact of this ubiquitous metal on ecosystems.
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Affiliation(s)
- Séverine Le Faucheur
- Institute F.-A. Forel, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, Versoix, Switzerland
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12
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Chiasson-Gould SA, Blais JM, Poulain AJ. Dissolved organic matter kinetically controls mercury bioavailability to bacteria. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:3153-61. [PMID: 24524696 DOI: 10.1021/es4038484] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Predicting the bioavailability of inorganic mercury (Hg) to bacteria that produce the potent bioaccumulative neurotoxin monomethylmercury remains one of the greatest challenges in predicting the environmental fate and transport of Hg. Dissolved organic matter (DOM) affects mercury methylation due to its influence on cell physiology (as a potential nutrient) and its influence on Hg(II) speciation in solution (as a complexing agent), therefore controlling Hg bioavailability. We assessed the role of DOM on Hg(II) bioavailability to a gram-negative bacterium bioreporter under oxic pseudo- and nonequilibrium conditions, using defined media and field samples spanning a wide range of DOM levels. Our results showed that Hg(II) was considerably more bioavailable under nonequilibrium conditions than when DOM was absent or when Hg(II) and DOM had reached pseudoequilibrium (24 h) prior to cell exposure. Under these enhanced uptake conditions, Hg(II) bioavailability followed a bell shaped curve as DOM concentrations increased, both for defined media and natural water samples, consistent with bioaccumulation results in a companion paper (this issue) observed for amphipods. Experiments also suggest that DOM may not only provide shuttle molecules facilitating Hg uptake, but also alter cell wall properties to facilitate the first steps toward Hg(II) internalization. We propose the existence of a short-lived yet critical time window (<24 h) during which DOM facilitates the entry of newly deposited Hg(II) into aquatic food webs, suggesting that the bulk of mercury incorporation in aquatic food webs would occur within hours following its deposition from the atmosphere.
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Affiliation(s)
- Sophie A Chiasson-Gould
- Department of Biology, University of Ottawa , 30 Marie-Curie, Ottawa, Ontario, K1N 6N5, Canada
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13
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Amaro-Estrada J, Ramírez-Solís A. Aqueous microsolvation of HgClOH. A systematic MP2 study of the HgClOH–(H2O)n species with n=1–4. COMPUT THEOR CHEM 2013. [DOI: 10.1016/j.comptc.2012.11.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Lehnherr I, St Louis VL, Kirk JL. Methylmercury cycling in High Arctic wetland ponds: controls on sedimentary production. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10523-31. [PMID: 22799567 DOI: 10.1021/es300577e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Methylmercury (MeHg) is a potent neurotoxin that has been demonstrated to biomagnify in Arctic freshwater foodwebs to levels that may be of concern to Inuit peoples subsisting on freshwater fish, for example. The key process initiating the bioaccumulation and biomagnification of MeHg in foodwebs is the methylation of inorganic Hg(II) to form MeHg, and ultimately how much MeHg enters foodwebs is controlled by the production and availability of MeHg in a particular water body. We used isotopically enriched Hg stable isotope tracers in sediment core incubations to measure potential rates of Hg(II) methylation and investigate the controls on MeHg production in High Arctic wetland ponds in the Lake Hazen region of northern Ellesmere Island (Nunavut, Canada). We show here that MeHg concentrations in sediments are primarily controlled by the sediment methylation potential and the quantity of Hg(II) available for methylation, but not by sediment demethylation potential. Furthermore, MeHg concentrations in pond waters are controlled by MeHg production in sediments, overall anaerobic microbial activity, and photodemethylation in the water column.
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Affiliation(s)
- Igor Lehnherr
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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15
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Attar AM, Kharkhaneh A, Etemadifar M, Keyhanian K, Davoudi V, Saadatnia M. Serum mercury level and multiple sclerosis. Biol Trace Elem Res 2012; 146:150-3. [PMID: 22068727 DOI: 10.1007/s12011-011-9239-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 10/13/2011] [Indexed: 10/15/2022]
Abstract
Exposure to heavy metals has been associated to a higher incidence of multiple sclerosis. In this work, we present a possible relationship between serum mercury levels and development of multiple sclerosis in Isfahan, the third largest city in Iran. Seventy-four patients affected by multiple sclerosis were retrieved from multiple sclerosis (MS) clinic in Isfahan, Iran. By matching sex and age, 74 healthy volunteers were chosen as control group. Blood samples were collected and serum mercury content was determined. Serum mercury level in MS patients was significantly higher than controls (9.6 ± 10.17 vs. 5.7 ± 8.6, P = 0.037). Concerning all MS patients, serum mercury value was significantly higher than the mercury concentration founded in control subjects {odd ratio: 2.39 (CI, 1.96-2.94), P = 0.00}. Serum mercury level is higher in MS patients with odd ratio equal to 2.39 compared with healthy individuals. It may reveal that high mercury levels in serum might help MS development in susceptible individuals. More studies with larger sample size are needed to confirm this hypothesis.
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Affiliation(s)
- Ahmad Movahedian Attar
- Department of Clinical Biochemistry, Isfahan Pharmaceutical Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
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Castro L, Dommergue A, Renard A, Ferrari C, Ramirez-Solis A, Maron L. Theoretical study of the solvation of HgCl2, HgClOH, Hg(OH)2 and HgCl3(-): a density functional theory cluster approach. Phys Chem Chem Phys 2011; 13:16772-9. [PMID: 21860852 DOI: 10.1039/c1cp22154j] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The determination of the solvation shell of Hg(II)-containing molecules and especially the interaction between Hg(II) and water molecules is the first requirement to understand the transmembrane passage of Hg into the cell. We report a systematic DFT study by stepwise solvation of HgCl(2) including up to 24 water molecules. In order to include pH and salinity effects, the solvation patterns of HgClOH, Hg(OH)(2) and HgCl(3)(-) were also studied using 24 water molecules. In all cases the hydrogen bond network is crucial to allow orbital-driven interactions between Hg(II) and the water molecules. DFT Born-Oppenheimer molecular dynamics simulations starting from the stable HgCl(2)-(H(2)O)(24) structure revealed that an HgCl(2)-(H(2)O)(3) trigonal bipyramid effective solute appears and then the remaining 21 water molecules build a complete first solvation shell, in the form of a water-clathrate. In the HgCl(2), HgClOH, Hg(OH)(2)-(H(2)O)(24) optimized structures Hg also directly interacts with 3 water molecules from an orbital point of view (three Hg-O donor-acceptor type bonds). All the other interactions are through hydrogen bonding. The cluster-derived solvation energies of HgCl(2), HgClOH and Hg(OH)(2) are estimated to be -34.4, -40.1 and -47.2 kcal mol(-1), respectively.
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Affiliation(s)
- Ludovic Castro
- Université de Toulouse, INSA, UPS, LPCNO, Toulouse, France
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Wu Y, Wang WX. Accumulation, subcellular distribution and toxicity of inorganic mercury and methylmercury in marine phytoplankton. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2011; 159:3097-105. [PMID: 21550705 DOI: 10.1016/j.envpol.2011.04.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 03/29/2011] [Accepted: 04/03/2011] [Indexed: 05/12/2023]
Abstract
We examined the accumulation, subcellular distribution, and toxicity of Hg(II) and MeHg in three marine phytoplankton (the diatom Thalassiosira pseudonana, the green alga Chlorella autotrophica, and the flagellate Isochrysis galbana). For MeHg, the inter-species toxic difference could be best interpreted by the total cellular or intracellular accumulation. For Hg(II), both I. galbana and T. pseudonana exhibited similar sensitivity, but they each accumulated a different level of Hg(II). A higher percentage of Hg(II) was bound to the cellular debris fraction in T. pseudonana than in I. galbana, implying that the cellular debris may play an important role in Hg(II) detoxification. Furthermore, heat-stable proteins were a major binding pool for MeHg, while the cellular debris was an important binding pool for Hg(II). Elucidating the different subcellular fates of Hg(II) and MeHg may help us understand their toxicity in marine phytoplankton at the bottom of aquatic food chains.
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Affiliation(s)
- Yun Wu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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Sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 as a model for understanding bacterial mercury methylation. Appl Environ Microbiol 2011; 77:3938-51. [PMID: 21515733 DOI: 10.1128/aem.02993-10] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We propose the use of Desulfovibrio desulfuricans ND132 as a model species for understanding the mechanism of microbial Hg methylation. Strain ND132 is an anaerobic dissimilatory sulfate-reducing bacterium (DSRB), isolated from estuarine mid-Chesapeake Bay sediments. It was chosen for study because of its exceptionally high rates of Hg methylation in culture and its metabolic similarity to the lost strain D. desulfuricans LS, the only organism for which methylation pathways have been partially defined. Strain ND132 is an incomplete oxidizer of short-chain fatty acids. It is capable of respiratory growth using fumarate as an electron acceptor, supporting growth without sulfide production. We used enriched stable Hg isotopes to show that ND132 simultaneously produces and degrades methylmercury (MeHg) during growth but does not produce elemental Hg. MeHg produced by cells is mainly excreted, and no MeHg is produced in spent medium. Mass balances for Hg and MeHg during the growth of cultures, including the distribution between filterable and particulate phases, illustrate how medium chemistry and growth phase dramatically affect Hg solubility and availability for methylation. The available information on Hg methylation among strains in the genus Desulfovibrio is summarized, and we present methylation rates for several previously untested species. About 50% of Desulfovibrio strains tested to date have the ability to produce MeHg. Importantly, the ability to produce MeHg is constitutive and does not confer Hg resistance. A 16S rRNA-based alignment of the genus Desulfovibrio allows the very preliminary assessment that there may be some evolutionary basis for the ability to produce MeHg within this genus.
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Larose C, Dommergue A, Marusczak N, Coves J, Ferrari CP, Schneider D. Bioavailable mercury cycling in polar snowpacks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:2150-2156. [PMID: 21341797 DOI: 10.1021/es103016x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Polar regions are subject to contamination by mercury (Hg) transported from lower latitudes, severely impacting human and animal health. Atmospheric Mercury Depletion Events (AMDEs) are an episodic process by which Hg is transferred from the atmospheric reservoir to arctic snowpacks. The fate of Hg deposited during these events is the subject of numerous studies, but its speciation remains unclear, especially in terms of environmentally relevant forms such as bioavailable mercury (BioHg). Here, using a bacterial mer-lux biosensor, we report the fraction of newly deposited Hg at the surface and at the bottom of the snowpack that is bioavailable. Snow samples were collected over a two-month arctic field campaign in 2008. In surface snow, BioHg is related to atmospheric Hg deposition and snow fall events were shown to contribute to higher proportions of BioHg than AMDEs. Based on our data, AMDEs represent a potential source of 20 t.y(-1) of BioHg, while wet and dry deposition pathways may provide 135-225 t.y(-1) of BioHg to Arctic surfaces.
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Affiliation(s)
- Catherine Larose
- Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS - Université Joseph Fourier Grenoble, 54 Rue Molière, 38400 St Martin d'Hères, France
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20
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Curli produced by Escherichia coli PHL628 provide protection from Hg(II). Appl Environ Microbiol 2010; 76:6939-41. [PMID: 20729321 DOI: 10.1128/aem.01254-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of curli, amyloid extracellular fibers, in the tolerance of Escherichia coli PHL628 to Hg(II) was examined. Our findings indicate that by sorbing Hg(II) extracellularly, curli protect the cells. To our knowledge, this is the first time a protective role of curli against toxic metals has been demonstrated.
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Picado F, Mendoza A, Cuadra S, Barmen G, Jakobsson K, Bengtsson G. Ecological, groundwater, and human health risk assessment in a mining region of Nicaragua. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2010; 30:916-933. [PMID: 20409041 DOI: 10.1111/j.1539-6924.2010.01387.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The objective of the present study was to integrate the relative risk from mercury exposure to stream biota, groundwater, and humans in the Río Artiguas (Sucio) river basin, Nicaragua, where local gold mining occurs. A hazard quotient was used as a common exchange rate in probabilistic estimations of exposure and effects by means of Monte Carlo simulations. The endpoint for stream organisms was the lethal no-observed-effect concentration (NOECs), for groundwater the WHO guideline and the inhibitory Hg concentrations in bacteria (IC), and for humans the tolerable daily intake (TDI) and the benchmark dose level with an uncertainty factor of 10 (BMDLs(0.1)). Macroinvertebrates and fish in the contaminated river are faced with a higher risk to suffer from exposure to Hg than humans eating contaminated fish and bacteria living in the groundwater. The river sediment is the most hazardous source for the macroinvertebrates, and macroinvertebrates make up the highest risk for fish. The distribution of body concentrations of Hg in fish in the mining areas of the basin may exceed the distribution of endpoint values with close to 100% probability. Similarly, the Hg concentration in cord blood of humans feeding on fish from the river was predicted to exceed the BMDLs(0.1) with about 10% probability. Most of the risk to the groundwater quality is confined to the vicinity of the gold refining plants and along the river, with a probability of about 20% to exceed the guideline value.
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Affiliation(s)
- Francisco Picado
- Centro para la Investigación en Recursos Acuáticos de Nicaragua, Universidad Nacional Autónoma de Nicaragua, Managua, Nicaragua
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Effect of pH on intracellular accumulation of trace concentrations of Hg(II) in Escherichia coli under anaerobic conditions, as measured using a mer-lux bioreporter. Appl Environ Microbiol 2007; 74:667-75. [PMID: 18083863 DOI: 10.1128/aem.00717-07] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of pH on the uptake and accumulation of Hg(II) by Escherichia coli were determined at trace, environmentally relevant, concentrations of Hg and under anaerobic conditions. Hg(II) accumulation was measured using inducible light production from E. coli HMS174 harboring a mer-lux bioreporter plasmid (pRB28). The effect of pH on the toxicity of higher concentrations of Hg(II) was measured using a constitutive lux plasmid (pRB27) in the same bacterial host. In this study, intracellular accumulation and toxicity of Hg(II) under anaerobic conditions were both significantly enhanced with decreasing pH over the pH range of 8 to 5. The pH effect on Hg(II) accumulation was most pronounced at pHs of <6, which substantially enhanced the Hg(II)-dependent light response. This enhanced response did not appear to be due to pH stress, as similar results were obtained whether cells were grown at the same pH as the assay or at a different pH. The enhanced accumulation of Hg(II) was also not related to differences in the chemical speciation of Hg(II) in the external medium resulting from the changes in pH. Experiments with Cd(II), also detectable by the mer-lux bioreporter system, showed that Cd(II) accumulation responded differently to pH changes than the net accumulation of Hg(II). Potential implications of these findings for our understanding of bacterial accumulation of Hg(II) under anaerobic conditions and for bacteria-mediated cycling of Hg(II) in aquatic ecosystems are discussed. Arguments are provided suggesting that this differential accumulation is due to changes in uptake of mercury.
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