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Peng X, Yang Y, Yang S, Li L, Song L. Recent advance of microbial mercury methylation in the environment. Appl Microbiol Biotechnol 2024; 108:235. [PMID: 38407657 PMCID: PMC10896945 DOI: 10.1007/s00253-023-12967-6] [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: 09/11/2023] [Revised: 12/02/2023] [Accepted: 12/13/2023] [Indexed: 02/27/2024]
Abstract
Methylmercury formation is mainly driven by microbial-mediated process. The mechanism of microbial mercury methylation has become a crucial research topic for understanding methylation in the environment. Pioneering studies of microbial mercury methylation are focusing on functional strain isolation, microbial community composition characterization, and mechanism elucidation in various environments. Therefore, the functional genes of microbial mercury methylation, global isolations of Hg methylation strains, and their methylation potential were systematically analyzed, and methylators in typical environments were extensively reviewed. The main drivers (key physicochemical factors and microbiota) of microbial mercury methylation were summarized and discussed. Though significant progress on the mechanism of the Hg microbial methylation has been explored in recent decade, it is still limited in several aspects, including (1) molecular biology techniques for identifying methylators; (2) characterization methods for mercury methylation potential; and (3) complex environmental properties (environmental factors, complex communities, etc.). Accordingly, strategies for studying the Hg microbial methylation mechanism were proposed. These strategies include the following: (1) the development of new molecular biology methods to characterize methylation potential; (2) treating the environment as a micro-ecosystem and studying them from a holistic perspective to clearly understand mercury methylation; (3) a more reasonable and sensitive inhibition test needs to be considered. KEY POINTS: • Global Hg microbial methylation is phylogenetically and functionally discussed. • The main drivers of microbial methylation are compared in various condition. • Future study of Hg microbial methylation is proposed.
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Affiliation(s)
- Xuya Peng
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, No. 174, Shapingba Street, Chongqing, 400045, China
| | - Yan Yang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, No. 174, Shapingba Street, Chongqing, 400045, China
| | - Shu Yang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, No. 174, Shapingba Street, Chongqing, 400045, China.
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China.
| | - Lei Li
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, No. 174, Shapingba Street, Chongqing, 400045, China
| | - Liyan Song
- School of resources and environmental engineering, Anhui University, No 111 Jiulong Road, Economic and Technology Development Zone, Hefei, 230601, People's Republic of China.
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2
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Zhou Y, Li S, Hintelmann H, Tang W, Zhong H. New insights into HgSe antagonism: Minor impact on inorganic Hg mobility while potential impacts on microorganisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169705. [PMID: 38160847 DOI: 10.1016/j.scitotenv.2023.169705] [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: 10/27/2023] [Revised: 12/13/2023] [Accepted: 12/25/2023] [Indexed: 01/03/2024]
Abstract
Selenium (Se) is a crucial antagonistic factor of mercury (Hg) methylation in soil, with the transformation of inorganic Hg (IHg) to inert mercury selenide (HgSe) being the key mechanism. However, little evidence has been provided of the reduced Hg mobility at environmentally relevant doses of Hg and Se, and the potential impacts of Se on the activities of microbial methylators have been largely ignored. This knowledge gap hinders effective mitigation for methylmercury (MeHg) risks, considering that Hg supply and microbial methylators serve as materials and workers for MeHg production in soils. By monitoring the mobility of IHg and microbial activities after Se spike, we reported that 1) active methylation might be the premise of HgSe antagonism, as higher decreases in MeHg net production were found in soils with higher constants of Hg methylation rate; 2) IHg mobility did not significantly change upon Se addition in soils with high DOC concentrations, challenging the long-held view of Hg immobilization by Se; and 3) the activities of iron-reducing bacteria (FeRB), an important group of microbial methylators, might be potentially regulated by Se addition at a dose of 4 mg/kg. These findings provide empirical evidence that IHg mobility may not be the limiting factor under Se amendment and suggest the potential impacts of Se on microbial activities.
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Affiliation(s)
- Yang Zhou
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China
| | - Shouying Li
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China
| | - Holger Hintelmann
- Department of Chemistry, Trent University, Peterborough, ON, Canada; Water Quality Centre, Trent University, Peterborough, ON, Canada
| | - Wenli Tang
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China.
| | - Huan Zhong
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China.
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Huang ZL, Yang ZB, Xu XX, Lei YJ, He JS, Yang S, Wong MH, Man YB, Cheng Z. Health risk assessment of mercury in Nile tilapia (Oreochromis niloticus) fed housefly maggots. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 852:158164. [PMID: 36055489 DOI: 10.1016/j.scitotenv.2022.158164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/04/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
The bioaccumulation of total mercury (THg) and methylmercury (MeHg) by housefly maggots (HM) during the conversion of food waste (vegetables and meat (VM) and rice waste) under various waste feed ratios were investigated. Subsequently, Nile tilapia (Oreochromis niloticus) were fed with the commercial feed, commercial dried HM, dried HM, and fresh HM, followed by a human health risk assessment of Hg via fish consumption. The THg concentrations of HM fed with food waste ranged from 39.5 to 100 μg kg-1 ww. Concentrations of MeHg in the maggots fed with 100 % vegetables and meat (VM) waste (13.7 ± 1.12 μg kg-1 ww) was significantly higher than that fed with other mixed ratios of rice waste and VM waste (p<0.05). Concentrations of MeHg were positively correlated with the weight and lipid content of houseflies (p<0.05). THg and MeHg concentrations in tilapia fed with the converted HM (dried and fresh HM) were 22.5 ± 6.50 μg kg-1 ww and 2.43 ± 0.36 μg kg-1 ww, respectively. There was no significant difference in MeHg between tilapia fed the four experiment diets (p>0.05). Health risk assessment results indicated that mercury in tilapia fed the food waste-grown HM did not pose potential health risks to humans (target hazard quotient < 1). In conclusion, HM could convert food waste into high-quality and safe fish feeds for cultivating tilapia.
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Affiliation(s)
- Zhong-Li Huang
- College of Environment, Sichuan Agricultural University, Chengdu, China
| | - Zhan-Biao Yang
- College of Environment, Sichuan Agricultural University, Chengdu, China
| | - Xiao-Xun Xu
- College of Environment, Sichuan Agricultural University, Chengdu, China
| | - Yong-Jia Lei
- College of Environment, Sichuan Agricultural University, Chengdu, China
| | - Jin-Song He
- College of Environment, Sichuan Agricultural University, Chengdu, China
| | - Song Yang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Ming Hung Wong
- Consortium on Health, Environment, Education, and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China
| | - Yu-Bon Man
- Consortium on Health, Environment, Education, and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China.
| | - Zhang Cheng
- College of Environment, Sichuan Agricultural University, Chengdu, China.
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Tran TAT, Dinh QT, Zhou F, Zhai H, Xue M, Du Z, Bañuelos GS, Liang D. Mechanisms underlying mercury detoxification in soil-plant systems after selenium application: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:46852-46876. [PMID: 34254235 DOI: 10.1007/s11356-021-15048-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 06/17/2021] [Indexed: 05/12/2023]
Abstract
Feasible countermeasures to mitigate mercury (Hg) accumulation and its deleterious effects on crops are urgently needed worldwide. Selenium (Se) fertilizer application is a cost-effective strategy to reduce Hg concentrations, promote agro-environmental sustainability and food safety, and decrease the public health risk posed by Hg-contaminated soils and its accumulation in food crops. This holistic review focuses on the processes and detoxification mechanisms of Hg in whole soil-plant systems after Se application. The reduction of Hg bioavailability in soil, the formation of inert HgSe or/and HgSe-containing proteinaceous complexes in the rhizosphere and/or roots, and the reduction of plant root uptake and translocation of Hg in plant after Se application are systemically discussed. In addition, the positive responses in plant physiological and biochemical processes to Se application under Hg stress are presented to show the possible mechanisms for protecting the plant. However, application of high levels Se showed synergistic toxic effect with Hg and inhibited plant growth. The effectiveness of Se application methods, rates, and species on Hg detoxification is compared. This review provides a good approach for plant production in Hg-contaminated areas to meet food security demands and reduce the public health risk.
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Affiliation(s)
- Thi Anh Thu Tran
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
- Faculty of Natural Resources and Environmental Management, Thu Dau Mot University, Thu Dau Mot City, Binh Duong, Vietnam
| | - Quang Toan Dinh
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
- Department of Natural Resources and Environment of Thanh Hoa, Thanh Hoa, 400570, Vietnam
| | - Fei Zhou
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Hui Zhai
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Mingyue Xue
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zekun Du
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Gary S Bañuelos
- USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, 93648-9757, USA
| | - Dongli Liang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China.
- Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, 712100, Shaanxi, China.
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5
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Cai W, Jin J, Dang F, Shi W, Zhou D. Mercury methylation from mercury selenide particles in soils. JOURNAL OF HAZARDOUS MATERIALS 2020; 400:123248. [PMID: 32585526 DOI: 10.1016/j.jhazmat.2020.123248] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/17/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Selenium-inhibited monomethylmercury (MeHg) production is an attractive strategy for mitigating the risks of MeHg exposure. However, it is poorly understood the methylation potential of mercury selenide (HgSe) particles during their aging in soils and sediments. Net MeHg production in three floodplain soils amended with different geochemical species of mercury selenides, i.e., dissolved inorganic mercury freshly mixed with selenite (Hg(II)+Se(IV)), HgSe nanoparticles (45.2 ± 0.5 nm) and microparticles (> 1 μm) is examined. Among mercury types, the methylation from nanoparticulate HgSe was similar to (0.05 - 0.5 % vs. 0.1 - 0.4 %, yellow brown soil) or 12.9 - 21.0 times lower (0.02 - 0.1 vs. 0.6 - 1.5 %, black soil) than that from Hg(II)+Se(IV); however, net MeHg production from HgSe nanoparticles (0.02 - 0.5 %) was 1.9 - 15.5 times greater than HgSe microparticles (< 0.05 %) in all soils. Furthermore, net MeHg production from nanoparticulate HgSe varied significantly among soil types, attributable to differences in soil organic matter contents (2.4-5.8%) and microbial methylator community among soils. These results address the importance of geochemical intermediates of mercury selenide precipitation reactions and soil properties in MeHg production, and develop Se-based remediation strategy to minimize negative effects of MeHg on environmental and human health.
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Affiliation(s)
- Weiping Cai
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jingmei Jin
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; College of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Fei Dang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Weilin Shi
- College of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Dongmei Zhou
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
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Gerson JR, Walters DM, Eagles-Smith CA, Bernhardt ES, Brandt JE. Do Two Wrongs Make a Right? Persistent Uncertainties Regarding Environmental Selenium-Mercury Interactions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9228-9234. [PMID: 32633495 DOI: 10.1021/acs.est.0c01894] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) is a pervasive environmental pollutant and contaminant of concern for both people and wildlife that has been a focus of environmental remediation efforts for decades. A growing body of literature has motivated calls for revising Hg consumption advisories to co-consider selenium (Se) levels in seafood and implies that remediating aquatic ecosystems with ecosystem-scale Se additions could be a robust solution to Hg contamination. Provided that elevated Se concentrations are also known toxicological threats to aquatic animals, we performed a literature search to evaluate the strength of evidence supporting three assertions underpinning the ameliorating benefits of Se: (1) dietary Se reduces MeHg toxicity in consumers; (2) environmental Se reduces Hg bioaccumulation and biomagnification in aquatic food webs; and (3) Se inhibits Hg bioavailability to, and/or methylmercury production by, microbial communities. Limited or ambiguous support for each criterion indicates that many scientific uncertainties and gaps remain regarding Se mediation of Hg behavior and toxicity in abiotic and biotic compartments. Significantly more information is needed to provide a strong scientific basis for modifying current fish consumption advisories on the basis of Se:Hg ratios or for applying Se amendments to remediate Hg-contaminated ecosystems.
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Affiliation(s)
- Jacqueline R Gerson
- Department of Biology, Duke University, Durham, North Carolina 27708, United States
| | - David M Walters
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, Missouri 65201, United States
| | - Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, Oregon 97330, United States
| | - Emily S Bernhardt
- Department of Biology, Duke University, Durham, North Carolina 27708, United States
| | - Jessica E Brandt
- Department of Natural Resources and the Environment & Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
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7
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Goñi-Urriza M, Klopp C, Ranchou-Peyruse M, Ranchou-Peyruse A, Monperrus M, Khalfaoui-Hassani B, Guyoneaud R. Genome insights of mercury methylation among Desulfovibrio and Pseudodesulfovibrio strains. Res Microbiol 2019; 171:3-12. [PMID: 31655199 DOI: 10.1016/j.resmic.2019.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 01/28/2023]
Abstract
Mercury methylation converts inorganic mercury into the toxic methylmercury, and the consequences of this transformation are worrisome for human health and the environment. This process is performed by anaerobic microorganisms, such as several strains related to Pseudodesulfovibrio and Desulfovibrio genera. In order to provide new insights into the molecular mechanisms of mercury methylation, we performed a comparative genomic analysis on mercury methylators and non-methylators from (Pseudo)Desulfovibrio strains. Our results showed that (Pseudo)Desulfovibrio species are phylogenetically and metabolically distant and consequently, these genera should be divided into various genera. Strains able to perform methylation are affiliated with one branch of the phylogenetic tree, but, except for hgcA and hgcB genes, no other specific genetic markers were found among methylating strains. hgcA and hgcB genes can be found adjacent or separated, but proximity between those genes does not promote higher mercury methylation. In addition, close examination of the non-methylator Pseudodesulfovibrio piezophilus C1TLV30 strain, showed a syntenic structure that suggests a recombination event and may have led to hgcB depletion. The genomic analyses identify also arsR gene coding for a putative regulator upstream hgcA. Both genes are cotranscribed suggesting a role of ArsR in hgcA expression and probably a role in mercury methylation.
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Affiliation(s)
- Marisol Goñi-Urriza
- Environmental Microbiology, CNRS/UNIV PAU & PAYS ADOUR/E2S UPPA, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, IPREM, UMR5254, Pau, France.
| | - Christophe Klopp
- Plateforme Bioinformatique Genotoul, UR875 Biométrie et Intelligence Artificielle, INRA, Castanet-Tolosan, France.
| | - Magali Ranchou-Peyruse
- Environmental Microbiology, CNRS/UNIV PAU & PAYS ADOUR/E2S UPPA, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, IPREM, UMR5254, Pau, France.
| | - Anthony Ranchou-Peyruse
- Environmental Microbiology, CNRS/UNIV PAU & PAYS ADOUR/E2S UPPA, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, IPREM, UMR5254, Pau, France.
| | - Mathilde Monperrus
- CNRS/UNIV PAU & PAYS ADOUR/E2S UPPA, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, IPREM, UMR5254, Anglet, France.
| | - Bahia Khalfaoui-Hassani
- Environmental Microbiology, CNRS/UNIV PAU & PAYS ADOUR/E2S UPPA, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, IPREM, UMR5254, Pau, France.
| | - Rémy Guyoneaud
- Environmental Microbiology, CNRS/UNIV PAU & PAYS ADOUR/E2S UPPA, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, IPREM, UMR5254, Pau, France.
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Xu X, Yan M, Liang L, Lu Q, Han J, Liu L, Feng X, Guo J, Wang Y, Qiu G. Impacts of selenium supplementation on soil mercury speciation, and inorganic mercury and methylmercury uptake in rice (Oryza sativa L.). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 249:647-654. [PMID: 30933762 DOI: 10.1016/j.envpol.2019.03.095] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/28/2019] [Accepted: 03/23/2019] [Indexed: 05/09/2023]
Abstract
Rice grain is known to accumulate methylmercury (MeHg) and has been confirmed to be the major pathway of MeHg exposure to residents in mercury (Hg) mining areas in China. Selenium (Se) supplementation has been proven to be effective in mitigating the toxicity of Hg. To understand how Se supplementation influences soil Hg speciation, a wide range of Se (0-500 mg/kg) was applied to Hg polluted paddy soils in this study, which decreased MeHg concentration in soil from 2.95 ± 0.36 to 0.69 ± 0.16 μg/kg (or 77%). After Se addition, humic acid state Hg (F4) was transformed into strong-complexed state Hg (F5), indicating that Hg bound up to the non-sulfur functional groups of humic acid (non-RSH) was released and reabsorbed by strong binding Se functional group (F5). As a result, inorganic Hg (IHg) was reduced by >48%, 18%, and 80% in root, stem, and grain, respectively, however, the reduction was not apparent in leaf. Substantial reductions were also found for MeHg in grain and root, but not in stem and leaf. Soil is suggested to be the main source of both MeHg and IHg in rice grain. Such a finding may provide an idea for improving Hg-polluted paddies through controlling soil IHg and MeHg. Further research on the molecular structure of the strong-complexed Hg in F5 should be conducted to elucidate the mechanism of Hg-Se antagonism.
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Affiliation(s)
- Xiaohang Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Min Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | | | - Qinhui Lu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | | | - Lin Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Jianyang Guo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Yajie Wang
- College of Food Safety, Guizhou Medical University, Guiyang, 550025, China
| | - Guangle Qiu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
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Bjerregaard P, St John T, Biuki NA, Biserova MP, Christensen A, Pedersen KL. Retention and distribution of methylmercury administered in the food in marine invertebrates: Effect of dietary selenium. MARINE ENVIRONMENTAL RESEARCH 2018; 138:76-83. [PMID: 29706366 DOI: 10.1016/j.marenvres.2018.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 06/08/2023]
Abstract
Methylmercury is transported along aquatic food chains from the lower trophic levels and selenium modulates the biokinetics of mercury in organisms in complex ways. We investigated the retention of orally administered methylmercury in various marine invertebrates and the effect of selenium hereon. Shrimps (Palaemon adpersus and P. elegans), blue mussels (Mytilus edulis), shore crabs (Carcinus maenas) and sea stars (Asterias rubens) eliminated methylmercury slowly (t½ = ½ to >1 year) and the copepod (Acartia tonsa) faster (t½ ∼ 12-24 h). Orally administered selenite augmented elimination of methylmercury in the copepod (in one of two experiments) and blue mussels, but not in shrimps, crabs and sea stars. Selenium generally alters the distribution of the body burden of mercury, leaving more mercury in muscle and less mercury in digestive glands or rest of the body - also in the species where total body retention is not affected.
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Affiliation(s)
- Poul Bjerregaard
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark.
| | - Tanja St John
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Narges Amrollahi Biuki
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark; Department of Marine Biology, Faculty of Marine Sciences and Technology, University of Hormozgan, Iran
| | - Maya Petrova Biserova
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Alan Christensen
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Knud Ladegaard Pedersen
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
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10
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Wang X, He Z, Luo H, Zhang M, Zhang D, Pan X, Gadd GM. Multiple-pathway remediation of mercury contamination by a versatile selenite-reducing bacterium. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 615:615-623. [PMID: 28988098 DOI: 10.1016/j.scitotenv.2017.09.336] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 09/29/2017] [Accepted: 09/30/2017] [Indexed: 06/07/2023]
Abstract
Mercury contamination is a global concern because of its high toxicity, persistence, bioaccumulative nature, long distance transport and wide distribution in the environment. In this study, the efficiency and multiple-pathway remediation mechanisms of Hg2+ by a selenite reducing Escherichia coli was assessed. E. coli can reduce Hg2+ to Hg+ and Hg0 and selenite to selenide at the same time. This makes a multiple-pathway mechanisms for removal of Hg2+ from water in addition to biosorption. It was found that when the original Hg2+ concentration was 40μgL-1, 93.2±2.8% of Hg2+ was removed from solution by E. coli. Of the total Hg removed, it was found that 3.3±0.1% was adsorbed to the bacterium, 2.0±0.5% was bioaccumulated, and 7.3±0.6% was volatilized into the ambient environment, and most (80.6±5.7%) Hg was removed as HgSe and HgCl precipitates and Hg0. On one hand, selenite is reduced to selenide and the latter further reacts with Hg2+ to form HgSe precipitates. On the other hand Hg2+ is successively reduced to Hg+, which forms solid HgCl, and Hg0. This is the report on bacterially transformation of Hg2+ to HgSe, HgCl and Hg0 via multiple pathways. It is suggested that E. coli or other selenite reducing microorganisms are promising candidates for mercury bioremediation of contaminated wastewaters, as well as simultaneous removal of Hg2+ and selenite.
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Affiliation(s)
- Xiaonan Wang
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanfei He
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Hongwei Luo
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ming Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Daoyong Zhang
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xiangliang Pan
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Geoffrey Michael Gadd
- Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, DD15EH, Scotland, UK
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11
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Bao P, Li GX, Sun GX, Xu YY, Meharg AA, Zhu YG. The role of sulfate-reducing prokaryotes in the coupling of element biogeochemical cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 613-614:398-408. [PMID: 28918271 DOI: 10.1016/j.scitotenv.2017.09.062] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/07/2017] [Accepted: 09/07/2017] [Indexed: 06/07/2023]
Abstract
Sulfate-reducing prokaryotes (SRP) represent a diverse group of heterotrophic and autotrophic microorganisms that are ubiquitous in anoxic habitats. In addition to their important role in both sulfur and carbon cycles, SRP are important biotic and abiotic regulators of a variety of sulfur-driven coupled biogeochemical cycling of elements, including: oxygen, nitrogen, chlorine, bromine, iodine and metal(loid)s. SRP gain energy form most of the coupling of element transformation. Once sulfate-reducing conditions are established, sulfide precipitation becomes the predominant abiotic mechanism of metal(loid)s transformation, followed by co-precipitation between metal(loid)s. Anthropogenic contamination, since the industrial revolution, has dramatically disturbed sulfur-driven biogeochemical cycling; making sulfur coupled elements transformation complicated and unpredictable. We hypothesise that sulfur might be detoxication agent for the organic and inorganic toxic compounds, through the metabolic activity of SRP. This review synthesizes the recent advances in the role of SRP in coupled biogeochemical cycling of diverse elements.
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Affiliation(s)
- Peng Bao
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; Ningbo Urban Environment Observation and Station, Chinese Academy of Sciences, Ningbo 315800, PR China
| | - Guo-Xiang Li
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; Ningbo Urban Environment Observation and Station, Chinese Academy of Sciences, Ningbo 315800, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Guo-Xin Sun
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100086, PR China
| | - Yao-Yang Xu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; Ningbo Urban Environment Observation and Station, Chinese Academy of Sciences, Ningbo 315800, PR China
| | - Andrew A Meharg
- Institute of Global Food Security, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom
| | - Yong-Guan Zhu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100086, PR China.
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12
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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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13
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Zhao L, Chen H, Lu X, Lin H, Christensen GA, Pierce EM, Gu B. Contrasting Effects of Dissolved Organic Matter on Mercury Methylation by Geobacter sulfurreducens PCA and Desulfovibrio desulfuricans ND132. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10468-10475. [PMID: 28806071 DOI: 10.1021/acs.est.7b02518] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Natural dissolved organic matter (DOM) affects mercury (Hg) redox reactions and anaerobic microbial methylation in the environment. Several studies have shown that DOM can enhance Hg methylation, especially under sulfidic conditions, whereas others show that DOM inhibits Hg methylation due to strong Hg-DOM complexation. In this study, we investigated and compared the effects of DOM on Hg methylation by an iron-reducing bacterium Geobacter sulfurreducens PCA and a sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 under nonsulfidic conditions. The methylation experiment was performed with washed cells either in the absence or presence of DOM or glutathione, both of which form strong complexes with Hg via thiol-functional groups. DOM was found to greatly inhibit Hg methylation by G. Sulfurreducens PCA but enhance Hg methylation by D. desulfuricans ND132 cells with increasing DOM concentration. These strain-dependent opposing effects of DOM were also observed with glutathione, suggesting that thiols in DOM likely played an essential role in affecting microbial Hg uptake and methylation. Additionally, DOM and glutathione greatly decreased Hg sorption by G. sulfurreducens PCA but showed little effect on D. desulfuricans ND132 cells, demonstrating that ND132 has a higher affinity to sorb or take up Hg than the PCA strain. These observations indicate that DOM effects on Hg methylation are bacterial strain specific, depend on the DOM:Hg ratio or site-specific conditions, and may thus offer new insights into the role of DOM in methylmercury production in the environment.
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Affiliation(s)
- Linduo Zhao
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Hongmei Chen
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Xia Lu
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Hui Lin
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Geoff A Christensen
- Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Eric M Pierce
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Baohua Gu
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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14
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In vitro study on antagonism mechanism of glutathione, sodium selenite and mercuric chloride. Talanta 2017; 171:262-269. [DOI: 10.1016/j.talanta.2017.04.074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/25/2017] [Accepted: 04/30/2017] [Indexed: 02/08/2023]
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15
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Tang W, Dang F, Evans D, Zhong H, Xiao L. Understanding reduced inorganic mercury accumulation in rice following selenium application: Selenium application routes, speciation and doses. CHEMOSPHERE 2017; 169:369-376. [PMID: 27886539 DOI: 10.1016/j.chemosphere.2016.11.087] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/04/2016] [Accepted: 11/15/2016] [Indexed: 05/09/2023]
Abstract
Selenium (Se) has recently been demonstrated to reduce inorganic mercury (IHg) accumulation in rice plants, while its mechanism is far from clear. Here, we aimed at exploring the potential effects of Se application routes (soil or foliar application with Se), speciation (selenite and selenate), and doses on IHg-Se antagonistic interactions in soil-rice systems. Results of our pot experiments indicated that soil application but not foliar application could evidently reduce tissue IHg concentrations (root: 0-48%, straw: 15-58%, and brown rice: 26-74%), although both application routes resulted in comparable Se accumulation in aboveground tissues. Meanwhile, IHg distribution in root generally increased with amended Se doses in soil, suggesting antagonistic interactions between IHg and Se in root. These results provided initial evidence that IHg-Se interactions in the rhizosphere (i.e., soil or rice root), instead of those in the aboveground tissues, could probably be more responsible for the reduced IHg bioaccumulation following Se application. Furthermore, Se dose rather than Se speciation was found to be more important in controlling IHg accumulation in rice. Our findings regarding the importance of IHg-Se interactions in the rhizosphere, together with the systematic investigation of key factors affecting IHg-Se antagonism and IHg bioaccumulation, advance our understanding of Hg dynamics in soil-rice systems.
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Affiliation(s)
- Wenli Tang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China.
| | - Fei Dang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, PR China.
| | - Douglas Evans
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China; Environmental and Resource Studies Program (ERS), Trent University, Peterborough, Ontario, Canada.
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China; Environmental and Life Sciences Program (EnLS), Trent University, Peterborough, Ontario, Canada.
| | - Lin Xiao
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China.
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16
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Wang YJ, Dang F, Zhao JT, Zhong H. Selenium inhibits sulfate-mediated methylmercury production in rice paddy soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 213:232-239. [PMID: 26901075 DOI: 10.1016/j.envpol.2016.02.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 02/11/2016] [Accepted: 02/11/2016] [Indexed: 06/05/2023]
Abstract
There is increasing interest in understanding factors controlling methylmercury (MeHg) production in mercury-contaminated rice paddy soil. Sulfate has been reported to affect MeHg biogeochemistry under anoxic conditions, and recent studies revealed that selenium (Se) could evidently reduce MeHg production in paddy soil. However, the controls of sulfate and Se on net MeHg production in paddy soil under fluctuating redox conditions remain largely unknown. Microcosm experiments were conducted to explore the effects of sulfate and Se on net MeHg production in rice paddy soil. Soil was added with 0-960 mg/kg sulfate, in the presence or absence of 3.0 mg/kg selenium (selenite or selenate), and incubated under anoxic (40 days) or suboxic conditions (5 days), simulating fluctuating redox conditions in rice paddy field. Sulfate addition moderately affected soil MeHg concentrations under anoxic conditions, while reoxidation resulted in evidently higher (18-40%) MeHg levels in sulfate amended soils than the control. The observed changes in net MeHg production were related to dynamics of sulfate and iron. However, Se could inhibit sulfate-mediated MeHg production in the soils: Se addition largely reduced net MeHg production in the soils (23-86%, compared to the control), despite of sulfate addition. Similarly, results of the pot experiments (i.e., rice cultivation in amended soils) indicated that soil MeHg levels were rather comparable in Se-amended soils during rice growth period, irrespective of added sulfate doses. The more important role of Se than sulfate in controlling MeHg production was explained by the formation of HgSe nanoparticles irrespective of the presence of sulfate, confirmed by TEM-EDX and XANES analysis. Our findings regarding the effects of sulfate and Se on net MeHg production in rice paddy soil together with the mechanistic explanation of the processes advance our understanding of MeHg dynamics and risk in soil-rice systems.
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Affiliation(s)
- Yong-Jie Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Fei Dang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, PR China
| | - Jia-Ting Zhao
- Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Laboratory of Metallomics and Metalloproteomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China; Environmental and Life Sciences Program (EnLS), Trent University, Peterborough, Ontario, Canada.
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Wang Y, Dang F, Zhong H, Wei Z, Li P. Effects of sulfate and selenite on mercury methylation in a mercury-contaminated rice paddy soil under anoxic conditions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:4602-4608. [PMID: 26520099 DOI: 10.1007/s11356-015-5696-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/26/2015] [Indexed: 06/05/2023]
Abstract
Biogeochemical cycling of sulfur and selenium (Se) could play an important role in methylmercury (MeHg) dynamics in soil, while their potential effects on MeHg production in rice paddy soil are less understood. The main objective of this study was to explore the effects of sulfate and selenite on net MeHg production in contaminated rice paddy soil, characterized with massive MeHg production and thus MeHg accumulation in rice. A series of microcosm incubation experiments were conducted using a contaminated paddy soil amended with sulfate and/or selenite, in which sulfate-reducing bacteria were mainly responsible for MeHg production. Our results demonstrated that sulfate addition reduced solid and dissolved MeHg levels in soils by ≤18 and ≤25 %, respectively. Compared to sulfate, selenite was more effective in inhibiting net MeHg production, and the inhibitory effect depended largely on amended selenite doses. Moreover, sulfate input played a dual role in affecting Hg-Se interactions in soil, which could be explained by the dynamics of sulfate under anoxic conditions. Therefore, the effects of sulfate and selenium input should be carefully considered when assessing risk of Hg in anoxic environments (e.g., rice paddy field and wetland).
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Affiliation(s)
- Yongjie Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China
| | - Fei Dang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China.
- Environmental and Life Sciences Program (EnLS), Trent University, Peterborough, Ontario, Canada.
| | - Zhongbo Wei
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China
| | - Ping Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, People's Republic of China
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Wang Y, Dang F, Evans RD, Zhong H, Zhao J, Zhou D. Mechanistic understanding of MeHg-Se antagonism in soil-rice systems: the key role of antagonism in soil. Sci Rep 2016; 6:19477. [PMID: 26778218 PMCID: PMC4726087 DOI: 10.1038/srep19477] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 12/09/2015] [Indexed: 11/09/2022] Open
Abstract
Methylmercury (MeHg) accumulation in rice has great implications for human health. Here, effects of selenium (Se) on MeHg availability to rice are explored by growing rice under soil or foliar fertilization with Se. Results indicate that soil amendment with Se could reduce MeHg levels in soil and grain (maximally 73%). In contrast, foliar fertilization with Se enhanced plant Se levels (3–12 folds) without affecting grain MeHg concentrations. This evidence, along with the distinct distribution of MeHg and Se within the plant, demonstrate for the first time that Se-induced reduction in soil MeHg levels (i.e., MeHg-Se antagonism in soil) rather than MeHg-Se interactions within the plant might be the key process triggering the decreased grain MeHg levels under Se amendment. The reduction in soil MeHg concentrations could be mainly attributed to the formation of Hg-Se complexes (detected by TEM-EDX and XANES) and thus reduced microbial MeHg production. Moreover, selenite and selenate were equally effective in reducing soil MeHg concentrations, possibly because of rapid changes in Se speciation. The dominant role of Se-induced reduction in soil MeHg levels, which has been largely underestimated previously, together with the possible mechanisms advance our mechanistic understanding about MeHg dynamics in soil-rice systems.
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Affiliation(s)
- Yongjie Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China
| | - Fei Dang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, P.R. China
| | - R Douglas Evans
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.,Environmental and Resource Studies Program (ERS), Trent University, Peterborough, Ontario, Canada
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.,Environmental and Life Sciences Program (EnLS), Trent University, Peterborough, Ontario, Canada
| | - Jiating Zhao
- Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Laboratory of Metallomics and Metalloproteomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Dongmei Zhou
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, P.R. China
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Karita K, Sakamoto M, Yoshida M, Tatsuta N, Nakai K, Iwai-Shimada M, Iwata T, Maeda E, Yaginuma-Sakurai K, Satoh H, Murata K. [Recent Epidemiological Studies on Methylmercury, Mercury and Selenium]. Nihon Eiseigaku Zasshi 2016; 71:236-251. [PMID: 27725427 DOI: 10.1265/jjh.71.236] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
More than sixty years has passed since the outbreak of Minamata disease, and high-level methylmercury contaminations now seem nonexistent in Japan. However, mercury has been continuously discharged from natural sources and industrial activities, and the health effects on children susceptible to methylmercury exposure at low levels, in addition to mercury contamination from mercury or gold mining areas in developing countries, become a worldwide concern. In this article, we provide a recent overview of epidemiological studies regarding methylmercury and mercury. The following findings were obtained. (1) Many papers on exposure assessment of methylmercury/mercury have been published since the Minamata Convention on Mercury was adopted in 2013. (2) The most crucial problem is child developmental neurotoxicity resulting from prenatal exposure to methylmercury, but its precise assessment seems to be difficult because most of such effects are neither severe nor specific. (3) Several problems raised in birth cohort studies (e.g., whether IQ deficits due to prenatal methylmercury exposure remain when the children become adults, or whether the postnatal exposure at low levels also causes such adverse effects in children) remain unsolved. (4) Concurrent exposure models of methylmercury, lead, polychlorinated biphenyls, aresenic, and organochlorine pesticides, as well as possible antagonists such as polyunsaturated fatty acids and selenium, should be considered in the study design because the exposure levels of methylmercury are extremely low in developed countries. (5) Further animal experiments and molecular biological studies, in addition to human studies, are required to clarify the mechanism of methylmercury toxicity.
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Affiliation(s)
- Kanae Karita
- Department of Hygiene and Public Health, Kyorin University School of Medicine
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A Post-Genomic View of the Ecophysiology, Catabolism and Biotechnological Relevance of Sulphate-Reducing Prokaryotes. Adv Microb Physiol 2015. [PMID: 26210106 DOI: 10.1016/bs.ampbs.2015.05.002] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Dissimilatory sulphate reduction is the unifying and defining trait of sulphate-reducing prokaryotes (SRP). In their predominant habitats, sulphate-rich marine sediments, SRP have long been recognized to be major players in the carbon and sulphur cycles. Other, more recently appreciated, ecophysiological roles include activity in the deep biosphere, symbiotic relations, syntrophic associations, human microbiome/health and long-distance electron transfer. SRP include a high diversity of organisms, with large nutritional versatility and broad metabolic capacities, including anaerobic degradation of aromatic compounds and hydrocarbons. Elucidation of novel catabolic capacities as well as progress in the understanding of metabolic and regulatory networks, energy metabolism, evolutionary processes and adaptation to changing environmental conditions has greatly benefited from genomics, functional OMICS approaches and advances in genetic accessibility and biochemical studies. Important biotechnological roles of SRP range from (i) wastewater and off gas treatment, (ii) bioremediation of metals and hydrocarbons and (iii) bioelectrochemistry, to undesired impacts such as (iv) souring in oil reservoirs and other environments, and (v) corrosion of iron and concrete. Here we review recent advances in our understanding of SRPs focusing mainly on works published after 2000. The wealth of publications in this period, covering many diverse areas, is a testimony to the large environmental, biogeochemical and technological relevance of these organisms and how much the field has progressed in these years, although many important questions and applications remain to be explored.
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Liu S, Kang M, Yan F, Peng D, Yang Y, He L, Wang M, Fang S, Zhang Z. Electrochemical DNA Biosensor Based on Microspheres of Cuprous Oxide and Nano-chitosan for Hg(II) Detection. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.02.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zhao J, Li Y, Li Y, Gao Y, Li B, Hu Y, Zhao Y, Chai Z. Selenium modulates mercury uptake and distribution in rice (Oryza sativa L.), in correlation with mercury species and exposure level. Metallomics 2014; 6:1951-7. [DOI: 10.1039/c4mt00170b] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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