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Xie F, Yuan Q, Meng Y, Luan F. Degradation of methylmercury into Hg(0) by the oxidation of iron(II) minerals. Water Res 2024; 256:121645. [PMID: 38653093 DOI: 10.1016/j.watres.2024.121645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/25/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Mercury contamination is a global concern, and the degradation and detoxification of methylmercury have gained significant attention due to its neurotoxicity and biomagnification within the food chain. However, the currently known pathways of abiotic demethylation are limited to light-induced photodegradation process and little is known about light-independent abiotic demethylation of methylmercury. In this study, we reported a novel abiotic pathway for the degradation of methylmercury through the oxidation of both mineral structural iron(II) and surface-adsorbed iron(II) in the absence of light. Our findings reveal that methylmercury can be oxidatively degraded by reactive oxygen species, specifically hydroxyl and superoxide radicals, which are generated from the oxidation of iron(II) minerals under dark conditions. Surprisingly, Hg(0) trapping experiments demonstrated that inorganic Hg(II) resulting from the oxidative degradation of methylmercury was rapidly reduced to gaseous Hg(0) by iron(II) minerals. The demethylation of methylmercury, coupled with the generation of Hg(0), suggests a potential natural attenuation process for methylmercury. Our results highlight the underappreciated roles of iron(II) minerals in the abiotic degradation of methylmercury and the release of gaseous Hg(0) into the atmosphere.
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Affiliation(s)
- Fuyu Xie
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Qingke Yuan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Ying Meng
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
| | - Fubo Luan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
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2
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Chen Y, Zhang Q, Zhang L, Liu X, Li Y, Liu R, Wang Y, Song Y, Li Y, Yin Y, Cai Y. Light-induced degradation of dimethylmercury in different natural waters. J Hazard Mater 2024; 470:134113. [PMID: 38565021 DOI: 10.1016/j.jhazmat.2024.134113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/20/2024] [Accepted: 03/21/2024] [Indexed: 04/04/2024]
Abstract
Photo-induced degradation of dimethylmercury (DMHg) is considered to be an important source for the generation of methylmercury (MMHg). However, studies on DMHg photodegradation are scarce, and it is even debatable about whether DMHg can be degraded in natural waters. Herein, we found that both DMHg and MMHg could be photodegraded in three natural waters collected from the Yellow River Delta, while in pure water only DMHg photodegradation occurred under visible light irradiation. The effects of different environmental factors on DMHg photodegradation were investigated, and the underlying mechanisms were elucidated by density functional theory calculations and a series of control experiments. Our findings revealed that the DMHg degradation rate was higher in the tidal creek water compared to Yellow River, Yan Lake, and purified water. NO3-, NO2-, and DOM could promote the photodegradation with DOM and NO3- showing particularly strong positive effects. Different light sources were employed, and UV light was found to be more effective in DMHg photodegradation. Moreover, MMHg was detected during the photodegradation of DMHg, confirming that the photochemical demethylation of DMHg is a source of MMHg in sunlit water. This work may provide a novel mechanistic insight into the DMHg photodegradation in natural waters and enrich the study of the global biogeochemical cycle of Hg.
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Affiliation(s)
- Yingying Chen
- Shandong Key Laboratory of Environmental Processes and Health, Qingdao Key Laboratory of Marine Pollutant Prevention, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Qingzhe Zhang
- Shandong Key Laboratory of Environmental Processes and Health, Qingdao Key Laboratory of Marine Pollutant Prevention, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Shenzhen Research Institute, Shandong University, Shenzhen 518057, China.
| | - Lian Zhang
- College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, China
| | - Xinning Liu
- Environment Research Institute, Shandong University, Qingdao 266237, China; Yantai Port United General Wharf Company, Yantai 264012, China
| | - Yanwei Li
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Runzeng Liu
- Shandong Key Laboratory of Environmental Processes and Health, Qingdao Key Laboratory of Marine Pollutant Prevention, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yingjun Wang
- Shandong Key Laboratory of Environmental Processes and Health, Qingdao Key Laboratory of Marine Pollutant Prevention, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yue Song
- Shandong Key Laboratory of Environmental Processes and Health, Qingdao Key Laboratory of Marine Pollutant Prevention, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yanbin Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Yongguang Yin
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yong Cai
- Shandong Key Laboratory of Environmental Processes and Health, Qingdao Key Laboratory of Marine Pollutant Prevention, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, United States.
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3
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Hu S, Zhang Y, Meng H, Yang Y, Chen G, Wang Q, Cheng K, Guo C, Li X, Liu T. Transformation and migration of Hg in a polluted alkaline paddy soil during flooding and drainage processes. Environ Pollut 2024; 345:123471. [PMID: 38336140 DOI: 10.1016/j.envpol.2024.123471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/14/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Mercury (Hg) contamination in paddy soils poses a health risk to rice consumers and the environmental behavior of Hg determines its toxicity. Thus, the variations of Hg speciation are worthy of exploring. In this study, microcosm and pot experiments were conducted to elucidate Hg transformation, methylation, bioaccumulation, and risk coupled with biogeochemical cycling of key elements in a Hg-polluted alkaline paddy soil. In microcosm and pot experiments, organic- and sulfide-bound and residual Hg accounted for more than 98% of total Hg, and total contents of dissolved, exchangeable, specifically adsorbed, and fulvic acid-bound Hg were less than 2% of total Hg, indicating a low mobility and environmental risk of Hg. The decrease of pH aroused from Fe(III), SO42-, and NO3- reduction promoted Hg mobility, whereas the increase of pH caused by Fe(II), S2-, and NH4+ oxidation reduced available Hg contents. Moreover, Fe-bearing minerals reduction and organic matter consumption promoted Hg mobility, whereas the produced HgS and Fe(II) oxidation increased Hg stability. During flooding, a fraction of inorganic Hg (IHg) could be transported into methylmercury (MeHg), and during drainage, MeHg would be converted back into IHg. After planting rice in an alkaline paddy soil, available Hg was below 0.3 mg kg-1. During rice growth, a portion of available Hg transport from paddy soil to rice, promoting Hg accumulation in rice grains. After rice ripening, IHg levels in rice tissues followed the trend: root > leaf > stem > grain, and IHg content in rice grain exceed 0.02 mg kg-1, but MeHg content in rice grain meets daily intake limit (37.45 μg kg-1). These results provide a basis for assessing the environmental risks and developing remediation strategies for Hg-contaminated redox-changing paddy fields as well as guaranteeing the safe production of rice grains.
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Affiliation(s)
- Shiwen Hu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Yufan Zhang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Hanbing Meng
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Yang Yang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Guojun Chen
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Qi Wang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Kuan Cheng
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Chao Guo
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiaomin Li
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China
| | - Tongxu Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environ. Pollut. Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
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Li D, Han X, Li Y. Mechanism of methylmercury photodegradation in the yellow sea and East China Sea: Dominant pathways, and role of sunlight spectrum and dissolved organic matter. Water Res 2024; 251:121112. [PMID: 38198975 DOI: 10.1016/j.watres.2024.121112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/31/2023] [Accepted: 01/05/2024] [Indexed: 01/12/2024]
Abstract
Mercury (Hg) is among the most concerned contaminants in the world due to its high toxicity, prevalent existence in the environments, and bioaccumulation via food chain. Methylmercury (MeHg) is the major form of Hg that accumulates along the food chain and poses threat to humans and wild life. Photodegradation is the dominant process that MeHg is eliminated from freshwater system and upper ocean. The formation of MeHg-dissolved organic matter (DOM) complexes and a variety of free radicals (FR)/reactive oxygen species (ROS) have been previously proposed to be involved in MeHg photodegradation. However, most of these studies were conducted in freshwater, and the mechanism of MeHg photodegradation in seawater remains unclear. In this study, the main pathways of MeHg photodegradation in the seawater of Yellow Sea (YS) and East China Sea (ECS) were investigated using FR/ ROS scavenger addition and DOM competing-ligand addition techniques. The results showed that direct photodegradation of MeHg-DOM complexes is the major pathway of MeHg photodegradation in the YS and ECS, while indirect photolysis of MeHg by hydroxyl radical (·OH) also plays a certain role at some sites. MeHg photodegradation was found to be mainly induced by ultraviolet (UV) light rather than visible light in YS and ECS seawater, and the contribution of UV-B was higher than UV-A which was opposite to that previously reported in freshwater. The energy for breaking the bond of CHg in MeHg-Cl complexes formed in seawater is higher than that in MeHg-DOM complexes and this may cause the relatively greater contribution of UV-B with higher energy to MeHg photodegradation in seawater. In addition, MeHg photodegradation in various fractions of natural DOM with different molecular weights, hydrophilicity/hydrophobicity and acid-base was tested. MeHg photodegradation rates (kd) varied in these fractions and kd in high molecular weight DOM and hydrophobic Acid (HOA) fractions were faster than that in the other fractions. A significantly positive correlation was observed between kd and thiol concentrations while there was no significant correlation between kd and other measured parameters representing the composition of DOM (specific UV absorbance at 254 nm (SUVA254), spectral slope (SR), chromophoric dissolved organic matter (CDOM), humification index (HIX), biological index (BIX) and fluorescent components). These results indicate that thiol may be the key functional group in DOM affecting the photodegradation of MeHg in the YS and ECS.
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Affiliation(s)
- Dan Li
- Weifang University, Weifang 261061, China
| | - Xiaoxiao Han
- Shandong Institute for Food and Drug Control, Jinan 250000, China
| | - Yanbin Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
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5
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Yu C, Peng M, Wang X, Pan X. Photochemical demethylation of methylmercury (MeHg) in aquatic systems: A review of MeHg species, mechanisms, and influencing factors. Environ Pollut 2024; 344:123297. [PMID: 38195023 DOI: 10.1016/j.envpol.2024.123297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/01/2023] [Accepted: 01/02/2024] [Indexed: 01/11/2024]
Abstract
Photodemethylation is the major pathway of methylmercury (MeHg) demethylation in surface water before uptake by the food chain, whose mechanisms and influence factors are still not completely understood. Here, we review the current knowledge on photodemethylation of MeHg and divide MeHg photolysis into three pathways: (1) direct photodemethylation, (2) free radical attack, and (3) intramolecular electron or energy transfer. In aquatic environments, dissolved organic matter is involved into all above pathways, and due to its complex compositions, properties and concentrations, DOM poses multiple functions during the PD of MeHg. DOM-MeHg complex (mainly by sulfur-containing molecules) might weaken the C-Hg bond and enhance PD through both direct and indirect pathways. In special, synergistic effects of both strong binding sites and chromophoric moieties in DOM might lead to intramolecular electron or energy transfer. Moreover, DOM might play a role of radical scavenger; while triplet state DOM, which is generated by chromophoric DOM under light, might become a source of free radicals. Apart from DOMs, transition metals, halides, NO3-, NO2-, and carbonates also act as radical initialaters or scavengers, and significantly pose effects on radical demethylation, which is generally mediated by hydroxyl radicals and singlet oxygen. Environmental factors such as pH, light wavelength, light intensity, dissolved oxygen, salinity, and suspended particles also affect the PD of MeHg. This study assessed previously published works on three major mechanisms, with the goal of providing general estimates for photodemethylation under various environment factors according to know effects, and highlighting the current uncertainties for future research directions.
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Affiliation(s)
- Chenghao Yu
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Mao Peng
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xiaonan Wang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xiangliang Pan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
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6
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Lei P, Zhu J, Zhang J, He H, Chen M, Zhong H. Algal organic matter inhibits methylmercury photodegradation in eutrophic lake water: A dynamic study. Sci Total Environ 2023; 899:165661. [PMID: 37474073 DOI: 10.1016/j.scitotenv.2023.165661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Algal organic matter (AOM) is a major component of dissolved organic matter (DOM) in eutrophic lakes and could impact the photodegradation of neurotoxic methylmercury (MeHg) in water. Predicting these effects, however, is challenging, largely due to the dynamic changes of AOM during algal decomposition. Here, we investigated the effects of AOM on MeHg photodegradation throughout the algal decomposition process and elucidated these effects by characterizing dynamic changes of AOM and exploring the respective roles of various reactive oxygen species (ROS). Our results reveal that AOM derived from algal decomposition significantly inhibits MeHg photodegradation, and the extent of this inhibition varies depending on the specific lakes (8-21 %, p < 0.05) and their eutrophication states (16-28 %, p < 0.05). The inhibitory effect gradually weakened as the decomposition progressed, which may be attributed to the dynamic changes in the quantity and quality of AOM. Moreover, hydroxyl radical (·OH) was found to be the main contributor in driving MeHg photodegradation (15-23 %) during the early stages of decomposition (day 0-3), while in the later stage (day 12-24), the role of singlet oxygen (1O2, 15-20 %) and (3DOM*, 21-30 %) gradually strengthened and these three ROS jointly drove MeHg photodegradation. Based on our findings and recent studies, we propose that AOM derived from algal decomposition plays a vital role in increasing the risk of MeHg in eutrophic lakes. It promotes MeHg formation while simultaneously inhibiting its photodegradation. Integrating AOM-MeHg interactions into Hg biogeochemical cycling models would reduce uncertainties when predicting MeHg risks.
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Affiliation(s)
- Pei Lei
- School of Environment, Nanjing Normal University, Nanjing 210023, China; State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Jinjie Zhu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China; Suzhou Wuzhong Environmental Monitoring Station, Suzhou 215104, China
| | - Jin Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Huan He
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Mingying Chen
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China; Environmental and Life Science Program (EnLS), Trent University, Peterborough, Ontario, Canada.
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7
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Seelen E, Liem-Nguyen V, Wünsch U, Baumann Z, Mason R, Skyllberg U, Björn E. Dissolved organic matter thiol concentrations determine methylmercury bioavailability across the terrestrial-marine aquatic continuum. Nat Commun 2023; 14:6728. [PMID: 37872168 PMCID: PMC10593767 DOI: 10.1038/s41467-023-42463-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 10/11/2023] [Indexed: 10/25/2023] Open
Abstract
The most critical step for methylmercury (MeHg) bioaccumulation in aquatic food webs is phytoplankton uptake of dissolved MeHg. Dissolved organic matter (DOM) has been known to influence MeHg uptake, but the mechanisms have remained unclear. Here we show that the concentration of DOM-associated thiol functional groups (DOM-RSH) varies substantially across contrasting aquatic systems and dictates MeHg speciation and bioavailability to phytoplankton. Across our 20 study sites, DOM-RSH concentrations decrease 40-fold from terrestrial to marine environments whereas dissolved organic carbon (DOC), the typical proxy for MeHg binding sites in DOM, only has a 5-fold decrease. MeHg accumulation into phytoplankton is shown to be directly linked to the concentration of specific MeHg binding sites (DOM-RSH), rather than DOC. Therefore, MeHg bioavailability increases systematically across the terrestrial-marine aquatic continuum as the DOM-RSH concentration decreases. Our results strongly suggest that measuring DOM-RSH concentrations will improve empirical models in phytoplankton uptake studies and will form a refined basis for modeling MeHg incorporation in aquatic food webs under various environmental conditions.
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Affiliation(s)
- Emily Seelen
- University of Connecticut, Department of Marine Sciences, Groton, CT, USA.
- University of Southern California, Earth Sciences, Los Angeles, CA, USA.
| | | | - Urban Wünsch
- Technical University of Denmark, National Institute of Aquatic Resources, Section for Oceans and Arctic, 2800, Lyngby, Denmark
| | - Zofia Baumann
- University of Connecticut, Department of Marine Sciences, Groton, CT, USA
| | - Robert Mason
- University of Connecticut, Department of Marine Sciences, Groton, CT, USA
| | - Ulf Skyllberg
- Swedish University of Agricultural Sciences, Department of Forest Ecology and Management Umeå, Umeå, Sweden
| | - Erik Björn
- Umeå University, Department of Chemistry, Umeå, Sweden.
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He Y, Yang X, Li Z, Wang T, Ma C, Wen X, Chen W, Zhang C. Aging rice straw reduces the bioavailability of mercury and methylmercury in paddy soil. Chemosphere 2023; 339:139711. [PMID: 37536532 DOI: 10.1016/j.chemosphere.2023.139711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/16/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Straw amendment is a prevalent agricultural practice worldwide, which can reduce air pollution and improve soil fertility. However, the impact of aging straw amendment on the bioavailability of mercury (Hg) and methylmercury (MeHg) in paddy soil remains unclear. To investigate this, incubation experiments were conducted using the diffusive gradient in thin-film technique. Results showed that amendments of dry-wet aging (DRS), photochemical aging (LRS), and freeze-thaw aging rice straw (FRS) reduced the bioavailable MeHg in paddy soil by 2.2-27.6%, 13.5-69.8%, and 23.5-86.1%, respectively, compared to fresh rice straw (RS) amendment. This result could be due to changes in soil properties such as soil pH and overlying water Fe and Mn as well as microbial abundance (including Clostridiaceae, Firmicutes, and Actinobacteriota). Simultaneously, The LRS and FRS amendments reduced bioavailable Hg in paddy soil by 20.0-40.8% and 17.1-48.6%, respectively, while DRS increased the bioavailable Hg by 15.8-120.0%. This could be attributed to changes in soil oxidation-reduction potential and overlying water SO42- content. Additionally, the results of sand culture experiments showed that the concentrations of Hg uptake by rice seedlings were 97.1-118.2%, 28.1-35.6%, and 198.0-217.1% higher in dissolved organic matter (DOM) derived from DRS, LRS, and FRS than RS, indicating that aging straw leached DOM may promote the Hg bioavailable when straw amendment. This result could be due to lower molecular weight and higher CO functional group content. These results provide new insight into how aging straw amendment affects the bioavailability of Hg and MeHg in paddy soil under different climates.
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Affiliation(s)
- Yubo He
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Xu Yang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Zihao Li
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Tantan Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Chi Ma
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Xin Wen
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Wenhao Chen
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Chang Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
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9
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Liu C, Ning Y, Liu J. Geochemical mercury pools regulate diverse communities of hgcA microbes and MeHg levels in paddy soils. Environ Pollut 2023; 334:122172. [PMID: 37437760 DOI: 10.1016/j.envpol.2023.122172] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/26/2023] [Accepted: 07/09/2023] [Indexed: 07/14/2023]
Abstract
Rice paddies are unique artificial wetlands generating methylmercury (MeHg), a highly potent neurotoxin. However, the impact of diverse mercury (Hg) pools on the Hg-methylating communities during rice growth is unclear. This study investigates soil treated with five mercury forms (HgCl2, α-HgS, β-HgS, nano-HgS, and Hg-DOM) at two levels (5 mg/kg and 50 mg/kg). The results showed a varying abundance of sulphate-reducing bacteria, Geobacteraceae, methanogens, and hgcA microbes in the soils across rice grown under different mercury treatments and concentrations. Soils treated with HgCl2, nano-HgS and β-HgS had higher than average levels of hgcA-methanogen abundance, and the abundance significantly and positively correlated with MeHg concentration in all samples (p < 0.05). The shifting trends in Hg-methylating microbial structure following treatment with α-HgS, β-HgS, nano-HgS and Hg-DOM at both 5 and 50 mg/kg Hg levels were diverse compared with the control group. HgCl2 treatment showed contrasting trends in community distribution of Hg methylators at 5 and 50 mg/kg Hg levels during rice growth. Dissolved organic carbon, redox potential and sulphate levels significantly correlated with variation in the Hg-methylating microbial community structure and MeHg production in soils.
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Affiliation(s)
- Chutong Liu
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China; Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan, 430074, China; Key Laboratory of Functional Geomaterials in China Nonmetallic Minerals Industry, China University of Geosciences, Wuhan, 430074, China
| | - Yongqiang Ning
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China; Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan, 430074, China; Key Laboratory of Functional Geomaterials in China Nonmetallic Minerals Industry, China University of Geosciences, Wuhan, 430074, China
| | - Jinling Liu
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China; Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan, 430074, China; Key Laboratory of Functional Geomaterials in China Nonmetallic Minerals Industry, China University of Geosciences, Wuhan, 430074, China.
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10
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Doroudian M, Thibault ME, Gailer J. N-Acetylcysteine Displaces Glutathionyl-Moieties from Hg 2+ and MeHg + to Form More Hydrophobic Complexes at Near-Physiological Conditions. Molecules 2023; 28:6762. [PMID: 37836605 PMCID: PMC10574133 DOI: 10.3390/molecules28196762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 10/15/2023] Open
Abstract
The anthropogenic release of Hg is associated with an increased human exposure risk. Since Hg2+ and MeHg+ have a high affinity for thiols, their interaction with L-glutathione (GSH) within mammalian cells is fundamentally involved in their toxicological chemistry and excretion. To gain insight into the interaction of these mercurials with multiple small molecular weight thiols, we have investigated their competitive interactions with GSH and N-acetylcysteine (NAC) at near-physiological conditions, using a liquid chromatographic approach. This approach involved the injection of each mercurial onto a reversed-phase (RP)-HPLC column (37 °C) using a PBS buffer mobile phase containing 5.0 mM GSH to simulate cytosolic conditions with Hg being detected in the column effluent by an inductively coupled plasma atomic emission spectrometer (ICP-AES). When the 5.0 mM GSH mobile phase was amended with up to 10 mM NAC, gradually increasing retention times of both mercurials were observed. To explain this behavior, the experiment with 5.0 mM NAC and 5.0 mM GSH was replicated using 50 mM Tris buffer (pH 7.4), and the Hg-containing fractions were analyzed by electrospray ionization mass spectrometry. The results revealed the presence of Hg(GS)(NAC) and Hg(NAC)2 for Hg2+ and MeHg(GS) and MeHg(NAC) for MeHg+, which suggests that the coordination/displacement of GS-moieties from each mercurial by the more hydrophobic NAC can explain their retention behavior. Since the biotransformations of both mercurials were observed at near-physiological conditions, they are of toxicological relevance as they provide a biomolecular explanation for some results that were obtained when animals were administered with each mercurial and NAC.
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Affiliation(s)
| | | | - Jürgen Gailer
- Department of Chemistry, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.D.); (M.E.T.)
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11
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Li Z, Wu Z, Shao B, Tanentzap AJ, Chi J, He W, Liu Y, Wang X, Zhao Y, Tong Y. Biodegradability of algal-derived dissolved organic matter and its influence on methylmercury uptake by phytoplankton. Water Res 2023; 242:120175. [PMID: 37301000 DOI: 10.1016/j.watres.2023.120175] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/30/2023] [Accepted: 06/04/2023] [Indexed: 06/12/2023]
Abstract
Methylmercury (MeHg) uptake by phytoplankton represents a key step in determining the exposure risks of aquatic organisms and human beings to this potent neurotoxin. Phytoplankton uptake is believed to be negatively related to dissolved organic matter (DOM) concentration in water. However, microorganisms can rapidly change DOM concentration and composition and subsequent impact on MeHg uptake by phytoplankton has rarely been tested. Here, we explored the influences of microbial degradation on the concentrations and molecular compositions of DOM derived from three common algal sources and tested their subsequent impacts on MeHg uptake by the widespread phytoplankton species Microcystis elabens. Our results indicated that dissolved organic carbon was degraded by 64.3‒74.1% within 28 days of incubating water with microbial consortia from a natural meso‑eutrophic river. Protein-like components in DOM were more readily degraded, while the numbers of molecular formula for peptides-like compounds had increased after 28 days' incubation, probably due to the production and release of bacterial metabolites. Microbial degradation made DOM more humic-like which was consistent with the positive correlations between changes in proportions of Peaks A and C and bacterial abundance in bacterial community structures as illustrated by 16S rRNA gene sequencing. Despite rapid losses of the bulk DOM during the incubation, we found that DOM degraded after 28 days still reduced the MeHg uptake by Microcystis elabens by 32.7‒52.7% relative to a control without microbial decomposers. Our findings emphasize that microbial degradation of DOM would not necessarily enhance the MeHg uptakes by phytoplankton and may become more powerful in inhibiting MeHg uptakes by phytoplankton. The potential roles of microbes in degrading DOM and changing the uptakes of MeHg at the base of food webs should now be incorporated into future risk assessments of aquatic Hg cycling.
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Affiliation(s)
- Zhike Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Bo Shao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Andrew J Tanentzap
- Ecosystems and Global Change Group, School of the Environment, Trent University, Peterborough, Ontario K9L 0G2, Canada
| | - Jie Chi
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Wei He
- School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Xuejun Wang
- College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; College of Ecology and Environment, Tibet University, Lhasa 850000, China.
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12
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Xie H, He L, Tian X, Zhang W, Cui L, Shang L, Zhao J, Li B, Li YF. Nano mercury selenide as a source of mercury for rice. Environ Pollut 2023; 318:120918. [PMID: 36563986 DOI: 10.1016/j.envpol.2022.120918] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/30/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Mercury (Hg) is a persistent and toxic metal while mercury selenide (HgSe) is generally considered as the environmental sink of Hg in its biogeochemical cycle. Recent studies found nano-sized HgSe (nano-HgSe) could be transformed by certain bacteria. This raises safety concerns about the application of selenium (Se) to curb Hg contamination in farmlands. Therefore, hydroponic experiments were performed in which rice plants were cultured with different concentrations of nano-HgSe and micro-sized HgSe (micro-HgSe) to explore their bioavailability and toxicity. It was found that both nano-HgSe and micro-HgSe did not affect the germination of rice seeds but affected the growth of rice seedlings. However, nano-HgSe could be more readily absorbed by roots and transferred to the aboveground parts compared to micro-HgSe. The highest Hg and Se levels were found to be 5255.67 ± 2496.14 μg/g and 1743.75 ± 61.87 μg/g, respectively in roots when exposed to 5000 mg/L nano-HgSe. Besides, small portion (1.2%) of methylmercury (MeHg) to total Hg was found accumulated in rice stem when exposed to 100 mg/L nano-HgSe, suggesting that nano-HgSe could be decomposed. Furthermore, nano-HgSe exposure brought oxidative damage to rice with decreased chlorophyll content and GSH-Px activity. In all, nano-HgSe was found to be more absorbable, transportable and methylated in rice plant compared to micro-HgSe. This suggests that although Se application in Hg contaminated farmland is an effective way to reduce the bioavailability of Hg, the risk of the possible remobilization of HgSe should not be neglected. Besides, the finding that nano-HgSe can act as an environmental source of Hg for plants deepens the understanding of biogeochemical cycle of Hg. More works are required to study the factors affecting the formation of nano-HgSe in the environment and the mechanisms of Hg methylation in rice plants after exposure to nano-HgSe.
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Affiliation(s)
- Hongxin Xie
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, & CAS-HKU Joint Laboratory of Metallomics on Health and Environment, & Beijing Metallomics Facility, & National Consortium for Excellence in Metallomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Lina He
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, & CAS-HKU Joint Laboratory of Metallomics on Health and Environment, & Beijing Metallomics Facility, & National Consortium for Excellence in Metallomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China; College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, 200092, China
| | - Xue Tian
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, & CAS-HKU Joint Laboratory of Metallomics on Health and Environment, & Beijing Metallomics Facility, & National Consortium for Excellence in Metallomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, Guizhou, China; Shandong Police College, Jinan, 250200, Shandong, China
| | - Liwei Cui
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lihai Shang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, Guizhou, China
| | - Jiating Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, & CAS-HKU Joint Laboratory of Metallomics on Health and Environment, & Beijing Metallomics Facility, & National Consortium for Excellence in Metallomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bai Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, & CAS-HKU Joint Laboratory of Metallomics on Health and Environment, & Beijing Metallomics Facility, & National Consortium for Excellence in Metallomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu-Feng Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, & CAS-HKU Joint Laboratory of Metallomics on Health and Environment, & Beijing Metallomics Facility, & National Consortium for Excellence in Metallomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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13
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Yang L, Yang G, Wang J, Xiong B, Guo P, Wang T, Du H, Ma M, Wang D. Seasonal changes in total mercury and methylmercury in subtropical decomposing litter correspond to the abundances of nitrogen-fixing and methylmercury-degrading bacteria. J Hazard Mater 2023; 442:130064. [PMID: 36182885 DOI: 10.1016/j.jhazmat.2022.130064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Previous research has found total mercury (THg) and methylmercury (MeHg) levels increase with litterfall decay, thus suggesting litterfall decomposition plays an essential role in the biogeochemical transformation of mercury (Hg). However, it remains unclear how Hg accumulates in the decaying litter, how bacterial taxa networks vary and what roles various microorganisms play during litterfall decomposition, especially nitrogen (N)-fixing, MeHg-degrading and Hg-methylating microbes. Here, we demonstrated as degradation proceeded, a gradually-complex network evolved for litterfall bacteria for the subtropical mixed broadleaf-conifer (MBC) forest, whereas a relatively static network existed for the evergreen broadleaf (EB) forest. N-fixing and MeHg-degrading bacteria dominated throughout litterfall decomposition process, with relative abundances of N-fixing genera and nifH copies maximum and relative abundances of MeHg-degrading bacteria and merAB copies minimum in summer. Hence, N-fixing bacteria likely mediate THg increase in the decomposing litterfall, while MeHg enhancement may be regulated by aerobic MeHg-degrading microbes which can transform MeHg to inorganic divalent Hg (Hg2+) or further to elemental Hg (Hg0). Together, this work elucidates variations of N-fixing and MeHg-degrading microbes in decaying litterfall and their relationships with Hg accumulation, providing novel insights into understanding the biogeochemical cycle of Hg in the forest ecosystem.
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Affiliation(s)
- Liping Yang
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Guang Yang
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Jueying Wang
- Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Bingcai Xiong
- Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Pan Guo
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Tao Wang
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Hongxia Du
- Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China.
| | - Ming Ma
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Dingyong Wang
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400715, China
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14
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Hadidi S. A high-efficiency decomposition method for mono and dimethylmercury induced by low-energy electron attachment (<≈7 eV): A computational insight into the decomposition mechanism of extremely toxic mercury compounds. Chemosphere 2023; 310:136845. [PMID: 36241118 DOI: 10.1016/j.chemosphere.2022.136845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/03/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Dimethylmercury (DMM) and monomethylmercury (MMM) are extremely toxic and dangerous environmental contaminants. Unfortunately, there is no effective way to remove these substances from the environment. This study looks into the efficient decomposition of DMM and MMM by low-energy electrons. The calculated quantum scattering properties reveal the presence of metastable electronic states in both molecules. An examination of the spatial features of the electronic resonances, as well as the computation and characterization of the vibrational normal modes, suggests possible bond break pathways of the metastable electronic states. Most electronic resonances result in the release of Hg(0), which is easily transported to the gas phase due to its low solubility in water and high volatility.
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Affiliation(s)
- Saba Hadidi
- Department of Inorganic Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran.
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15
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Bradford MA, Mallory ML, O'Driscoll NJ. The Complex Interactions Between Sediment Geochemistry, Methylmercury Production, and Bioaccumulation in Intertidal Estuarine Ecosystems: A Focused Review. Bull Environ Contam Toxicol 2022; 110:26. [PMID: 36571620 DOI: 10.1007/s00128-022-03653-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/20/2022] [Indexed: 06/17/2023]
Abstract
Due to their natural geochemistry, intertidal estuarine ecosystems are vulnerable to bioaccumulation of methylmercury (MeHg), a neurotoxin that readily bioaccumulates in organisms. Determining MeHg concentrations in intertidal invertebrates at the base of the food web is crucial in determining MeHg exposure in higher trophic level organisms like fish and birds. The processes that govern the production of MeHg in coastal ecosystems are influenced by many geochemical factors including sulfur species, organic matter, and salinity. The interactions of these factors with mercury are complex, and a wide variety of results have been reported in the literature. This paper reviews conceptual models to better clarify the various geochemical and physical factors that impact MeHg production and bioavailability in intertidal ecosystems.
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Affiliation(s)
| | - Mark L Mallory
- Biology Department, Acadia University, Wolfville, NS, Canada
| | - Nelson J O'Driscoll
- Earth and Environmental Science Department, Acadia University, Wolfville, NS, Canada
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16
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Zhang L, Song Y, Li Y, Yin Y, Cai Y. Role of light in methylmercury photodegradation: From irradiation to absorption in the presence of organic ligands. Sci Total Environ 2022; 848:157550. [PMID: 35907539 DOI: 10.1016/j.scitotenv.2022.157550] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/07/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
Photochemical degradation acts as the principal sink for methylmercury (MeHg) in surface water, which is regulated by light and solution matrix (especially the presence of dissolved organic matter, DOM). The spectral composition of light irradiation and the light absorption properties of reaction media (often exerted by DOM) are important in MeHg photodegradation, which has not yet been clearly resolved. Aiming to understand the role of light in MeHg photodegradation from the perspectives of both light irradiation and absorption, we investigated the photodegradation of MeHg under different simulated sunlight sources, with and without DOM model compounds of different molecular structures. The results show that the photodegradation of MeHg under different sunlight irradiation yields distinct first-order date constant, mainly due to the slight difference in UVB composition. The degradation of MeHg without DOM under a light source with high intensity in the UV region and no MeHg degradation under the UV-filtered light even in the presence of DOM showed the importance of UV lights in MeHg photodegradation. The use of ultrapure water as a reaction medium may be subject to MeHg loss through vessel adsorption, not just photolysis. Additionally, this work found that the type and position of coexisting substituents on aromatic thiols play a critical role in improving the photodegradation of MeHg, following amino > hydroxyl > carboxyl, para > meta > ortho. Based on the characterization of ultraviolet-visible absorption spectra and our previous work, it was concluded that the presence of DOM could induce red-shift in light absorption and reduce the electronic transition energy of the CHg bond, facilitating MeHg photodegradation. The structures of DOM affect the light absorption properties, which are related to MeHg photodegradation.
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Affiliation(s)
- Lian Zhang
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yue Song
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
| | - Yanbin Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Yongguang Yin
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yong Cai
- Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, United States
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17
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Mija A, Jules M B, Alexandre J P. Arsenate decreases production of methylmercury across increasing sulfate concentration amendments in freshwater lake sediments. Environ Sci Process Impacts 2022; 24:1508-1516. [PMID: 35671194 DOI: 10.1039/d1em00543j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Arsenic (As) and sulfate pollution are often found co-occurring as a result of smelting metal ores. Previous studies showed that sulfate reducing microbes (SRMs) can use As(V) as a terminal electron acceptor, while others reported that SRMs are the main mercury (Hg) methylators in freshwater systems. However, we have yet to fully explore how As(V) can affect methylmercury (MeHg) production. In this study, we examined whether additions of As(V) and sulfate in freshwater sediments collected near a major gold mine with a history of S and As emissions affect Hg methylation. First, we show that Hg methylation in lake sediments was primarily limited by carbon substrate availability rather than by that of sulfate as terminal electron acceptors. Then, under conditions where carbon is not limiting, sulfate addition to the system significantly increased Hg methylation rate constants. Finally, we show that MeHg production rates in sediments significantly decreased with increasing As(V) concentrations, regardless of the sulfate concentration amended to sediments. This work underscores the apparent antagonistic effects of As(V) on the one hand, and carbon and sulfate on the other hand on the kinetics of Hg methylation. Arsenic controls on Hg methylation are complex and a combination of direct impact on the methylators' fitness, the formation of As-bearing mineral phases affecting Hg bioavailability, or changes in the microbial community structures over increasing As concentrations should be the focus of additional investigations.
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Affiliation(s)
- Aždajić Mija
- Department of Biology, University of Ottawa, 30 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada.
| | - Blais Jules M
- Department of Biology, University of Ottawa, 30 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada.
| | - Poulain Alexandre J
- Department of Biology, University of Ottawa, 30 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada.
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18
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Luo H, Cheng Q, He D, Zeng G, Sun J, Li J, Pan X. Binding of methylmercury to humic acids (HA): Influence of solar radiation and sulfide addition reaction of HA. Sci Total Environ 2022; 827:154356. [PMID: 35259369 DOI: 10.1016/j.scitotenv.2022.154356] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/02/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Methylmercury (MeHg) is a neurotoxin that bioaccumulates in organisms and it forms strong complexes with reduced sulfur-containing ligands in dissolved organic matter (DOM). In the present study, the influences of solar radiation and sulfide addition reaction of humic acids (HA) on MeHg binding to HA were investigated using synchronous fluorescence and FT-IR two-dimensional correlation spectroscopic (2DCOS) analysis. Results showed that the complexation of fluorescent fractions of HA and sulfur-reacted HA (S-HA) with MeHg was not significantly affected by photoreaction treatments and the affinity of fluorescent fractions followed the order of protein-like fractions > humic-like fractions > fulvic-like fractions for both HA and S-HA. FT-IR 2DCOS analysis showed that the affinity of various binding sites in DOM for MeHg changed under different photoreaction treatments. Under dark treatment, small molecular compounds with low humification degree such as aromatic amino acids may be the site with the strongest binding ability to MeHg in HA, whereas aliphatic amino acids and sulfur-containing groups from sulfide addition reactions play a role in complexing of S-HA and MeHg. Under BS treatment (irradiation of DOM before MeHg binding), aliphatic compounds in HA preferentially bind to MeHg and aliphatic amino acids are the components with the strongest complexing ability; but for S-HA binding to MeHg, unsaturated functional groups and aromatic groups are more sensitive (alkenes > alkanes, phenols > alcohols). Under AS treatment (irradiation of DOM after MeHg binding), unsaturated bonds and aromatic compounds in HA preferentially bind to MeHg and aromatic amino acids show the strongest complexing ability; but for S-HA binding to MeHg, aliphatic groups show the strongest complexing ability (alkanes, alkenes > aromatics). These findings help us to better understand the complexation mechanisms between MeHg and DOM.
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Affiliation(s)
- Hongwei Luo
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Qianqian Cheng
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Dongqin He
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ganning Zeng
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jianqiang Sun
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jun Li
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xiangliang Pan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
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19
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Wu Z, Li Z, Shao B, Zhang Y, He W, Lu Y, Gusvitskii K, Zhao Y, Liu Y, Wang X, Tong Y. Impact of dissolved organic matter and environmental factors on methylmercury concentrations across aquatic ecosystems inferred from a global dataset. Chemosphere 2022; 294:133713. [PMID: 35074323 DOI: 10.1016/j.chemosphere.2022.133713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Mercury (Hg) input into ecosystems is estimated to have increased by twofold to fivefold since the industrial revolution. In aquatic ecosystems, methylmercury (MeHg) receives the most attentions of all the Hg species due to its neurotoxicity and strong bioaccumulation capacity in food chain. Dissolved organic matter (DOM) is crucial in impacting aquatic Hg transformation. However, only few spatially constrained studies have attempted to quantify the relative importance of DOM and other factors (e.g., Hg availability, temperature, pH, and land-use type) on MeHg concentration. In this study, we collected data of 585 water samples at 373 sites globally, including lakes, rivers, estuaries, and wetlands, and characterized the global pattern of MeHg distribution and environmental drivers of aquatic MeHg concentration. Our results showed that MeHg concentrations ranged from detection limits to 11 (geometric mean 0.11 and average 0.29) ng/L, and the highest MeHg concentration and Hg methylation potential were observed in wetlands. A positive relationship was observed between MeHg fraction in the total mercury (THg) and DOM for all the aquatic ecosystems. Using the structural equation modeling, we found that Hg availability was a dominant factor in impacting water MeHg concentration followed by DOM. According to 129 samples of specific DOM source information, we found that the percentage of THg as MeHg (%MeHg) in water dominated by the autochthonous DOM was higher than that dominated by the allochthonous DOM. Our results could advance understanding of aquatic Hg cycling and their environmental drivers, which are fundamental for predicting and mitigating MeHg productions and its potential health risks for humans.
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Affiliation(s)
- Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Zhike Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Bo Shao
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yiyan Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Wei He
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Yiren Lu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Kair Gusvitskii
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yurong Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuejun Wang
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
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20
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Madabeni A, Nogara PA, Bortoli M, Rocha JB, Orian L. Effect of Methylmercury Binding on the Peroxide-Reducing Potential of Cysteine and Selenocysteine. Inorg Chem 2021; 60:4646-4656. [PMID: 33587617 PMCID: PMC8763373 DOI: 10.1021/acs.inorgchem.0c03619] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Indexed: 01/09/2023]
Abstract
Methylmercury (CH3Hg+) binding to catalytically fundamental cysteine and selenocysteine of peroxide-reducing enzymes has long been postulated as the origin of its toxicological activity. Only very recently, CH3Hg+ binding to the selenocysteine of thioredoxin reductase has been directly observed [Pickering, I. J. Inorg. Chem., 2020, 59, 2711-2718], but the precise influence of the toxicant on the peroxide-reducing potential of such a residue has never been investigated. In this work, we employ state-of-the-art density functional theory calculations to study the reactivity of molecular models of the free and toxified enzymes. Trends in activation energies are discussed with attention to the biological consequences and are rationalized within the chemically intuitive framework provided by the activation strain model. With respect to the free, protonated amino acids, CH3Hg+ binding promotes oxidation of the S or Se nucleus, suggesting that chalcogenoxide formation might occur in the toxified enzyme, even if the actual rate of peroxide reduction is almost certainly lowered as suggested by comparison with fully deprotonated amino acids models.
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Affiliation(s)
- Andrea Madabeni
- Dipartimento
di Scienze Chimiche, Università degli
Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Pablo A. Nogara
- Dipartimento
di Scienze Chimiche, Università degli
Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
- Departamento
de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria (UFSM), 97105-900 Santa
Maria, RS, Brazil
| | - Marco Bortoli
- Dipartimento
di Scienze Chimiche, Università degli
Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - João B.
T. Rocha
- Departamento
de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria (UFSM), 97105-900 Santa
Maria, RS, Brazil
| | - Laura Orian
- Dipartimento
di Scienze Chimiche, Università degli
Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
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21
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Strain JJ, Love TM, Yeates AJ, Weller D, Mulhern MS, McSorley EM, Thurston SW, Watson GE, Mruzek D, Broberg K, Rand MD, Henderson J, Shamlaye CF, Myers GJ, Davidson PW, van Wijngaarden E. Associations of prenatal methylmercury exposure and maternal polyunsaturated fatty acid status with neurodevelopmental outcomes at 7 years of age: results from the Seychelles Child Development Study Nutrition Cohort 2. Am J Clin Nutr 2021; 113:304-313. [PMID: 33330939 PMCID: PMC7851824 DOI: 10.1093/ajcn/nqaa338] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 10/22/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Fish is a primary source of protein and n-3 PUFA but also contains methylmercury (MeHg), a naturally occurring neurotoxicant to which, at sufficient exposure levels, the developing fetal brain is particularly sensitive. OBJECTIVES To examine the association between prenatal MeHg and maternal status of n-3 and n-6 PUFA with neurodevelopment, and to determine whether PUFA might modify prenatal MeHg associations with neurodevelopment. METHODS We examined the Seychelles Child Development Study Nutrition Cohort 2 (NC2) at age 7 y. We used a sophisticated and extensive neurodevelopmental test battery that addressed 17 specific outcomes in multiple neurodevelopmental domains: cognition, executive and psychomotor function, language development, behavior, scholastic achievement, and social communication. Analyses were undertaken on 1237 mother-child pairs with complete covariate data (after exclusions) and a measure of at least 1 outcome. We examined the main and interactive associations of prenatal MeHg exposure (measured as maternal hair mercury) and prenatal PUFA status (measured in maternal serum at 28 weeks' gestation) on child neurodevelopmental outcomes using linear regression models. We applied the Bonferroni correction to account for multiple comparisons and considered P values <0.0029 to be statistically significant. RESULTS Prenatal MeHg exposure and maternal DHA and arachidonic acid (20:4n-6) (AA) status were not significantly associated with any neurodevelopmental outcomes. Findings for 4 outcomes encompassing executive function, cognition, and linguistic skills suggested better performance with an increasing maternal n-6:n-3 PUFA ratio (P values ranging from 0.004 to 0.05), but none of these associations were significant after adjusting for multiple comparisons. No significant interaction between MeHg exposure and PUFA status was present. CONCLUSIONS Our findings do not support an association between prenatal MeHg exposure or maternal DHA and AA status with neurodevelopmental outcomes at age 7 y. The roles of n-6 and n-3 PUFA in child neurodevelopment need further research.
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Affiliation(s)
- JJ Strain
- Nutrition Innovation Centre for Food & Health, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Tanzy M Love
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Alison J Yeates
- Nutrition Innovation Centre for Food & Health, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Daniel Weller
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Maria S Mulhern
- Nutrition Innovation Centre for Food & Health, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Emeir M McSorley
- Nutrition Innovation Centre for Food & Health, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Sally W Thurston
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Gene E Watson
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Daniel Mruzek
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Karin Broberg
- Unit of Metals and Health, Institute of Environmental Medicine, Metals and Health, Karolinska Institute, Stockholm, Sweden
- Division of Occupational and Environmental Medicine, Laboratory of Medicine, Lund University, Lund, Sweden
| | - Matthew D Rand
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | | | | | - Gary J Myers
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Philip W Davidson
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
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22
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Yao C, He T, Xu Y, Ran S, Qian X, Long S. Mercury bioaccumulation in zooplankton and its relationship with eutrophication in the waters in the karst region of Guizhou Province, Southwest China. Environ Sci Pollut Res Int 2020; 27:8596-8610. [PMID: 31907806 DOI: 10.1007/s11356-019-07479-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
Zooplankton play an important role in the transfer of mercury (Hg) from the lower to upper trophic positions in the food chain. In this study, total mercury (THg) and methylmercury (MeHg) levels were measured in three size fractions of zooplankton collected from three reservoirs (Hongfeng, Baihua, and Aha Reservoir) and one wetland in karst areas to understand mercury accumulation in zooplankton from alkaline environments. The results showed that the alkaline waters had lower zooplankton MeHg levels (0.1 to 66.8 ng g-1) than most of the acidic waters reported. However, the zooplankton THg levels (6.3 to 494.9 ng g-1) were comparable. The macro-zooplankton (> 500 μm) had significantly higher THg and MeHg levels than meso-zooplankton (116 to 500 μm) in the three reservoirs at all seasons, which showed biomagnification of mercury in the food chain. The correlation between Hg in water and zooplankton and Hg in zooplankton of different sizes indicated that THg bioaccumulation in zooplankton was related to the THg levels in water; however, MeHg bioaccumulation in zooplankton was controlled by many other factors, such as their feeding and living habits. In the three reservoirs, the THg and MeHg concentrations in zooplankton decreased with increasing eutrophication. However, compared with the three reservoirs, Caohai Wetland, with large amounts of aquatic plants, had a much lower trophic level and higher MeHg content in water but much lower zooplankton MeHg levels and bioaccumulation factors (BAFs). The large amounts of plant residue might dilute mercury in the food chain, revealing that high primary production could result in lower Hg bioaccumulation, rather than only being influenced by nutrient levels.
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Affiliation(s)
- Cong Yao
- Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang, 550003, China
| | - Tianrong He
- Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang, 550003, China.
| | - Yiyuan Xu
- Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang, 550003, China
| | - Shu Ran
- Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang, 550003, China
| | - Xiaoli Qian
- The School of Resources and Environment Engineering, Guizhou University, Guiyang, 550003, China
| | - Shengxing Long
- Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang, 550003, China
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23
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Piccoli BC, Alvim JC, da Silva FD, Nogara PA, Olagoke OC, Aschner M, Oliveira CS, Rocha JBT. High level of methylmercury exposure causes persisted toxicity in Nauphoeta cinerea. Environ Sci Pollut Res Int 2020; 27:4799-4813. [PMID: 31845250 DOI: 10.1007/s11356-019-06989-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 11/06/2019] [Indexed: 06/10/2023]
Abstract
Methylmercury (MeHg+) is a neurotoxicant abundantly present in the environment. The long-term effects of MeHg+ have been investigated in rodents, yet data on the long-term or persisted toxicity of MeHg+ in invertebrates is scanty. Here, we examined the acute, intermediate, and chronic effects upon dietary administration of MeHg+ in nymphs of Nauphoeta cinerea. Besides, the potential reversibility of the toxic effects of MeHg+ after a detoxification period was evaluated. Nymphs were exposed to diets containing 0 (control), 2.5, 25, and 100 μg MeHg+/g of diet for 10, 30, and 90 days. Additional groups of nymphs were fed with the same dose of MeHg+ for 30 days and then were subjected to a detoxification period for 60 days. The nymphs exposed to 100 μg MeHg+/g succumbed to a high mortality rate, along with multiple biochemical (increase of reactive oxygen species production and glutathione S-transferase activity, as well as decrease in the acetylcholinesterase activity) and behavioral alterations. We observed delayed mortality rate and behavioral alterations in nymphs exposed to 100 μg MeHg+/g for 30 days and subsequently subjected to 60 days of detoxification. However, the biochemical alterations did not persist throughout the detoxification period. In conclusion, our results established the persistent toxic effect of MeHg+ even after a prolonged detoxification period and evidenced the use of N. cinerea as an alternative model to study the toxicity of MeHg+.
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Affiliation(s)
- Bruna C Piccoli
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Jéssica C Alvim
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Fernanda D da Silva
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Pablo A Nogara
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Olawande C Olagoke
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Cláudia S Oliveira
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, PR, Brazil.
- Faculdades Pequeno Príncipe, Curitiba, PR, Brazil.
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
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24
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Ji X, Liu C, Pan G. Interfacial oxygen nanobubbles reduce methylmercury production ability of sediments in eutrophic waters. Ecotoxicol Environ Saf 2020; 188:109888. [PMID: 31706242 DOI: 10.1016/j.ecoenv.2019.109888] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/23/2019] [Accepted: 10/27/2019] [Indexed: 06/10/2023]
Abstract
Eutrophication can induce hypoxia/anoxia and rich organic matter at the sediment-water interface in surface waters. When eutrophic waters are impacted with mercury (Hg) pollution, methylmercury (MeHg) production ability (MPA) of surface sediment would increase and more MeHg might be produced. To tackle this risk, this study firstly collected samples of surface sediment and overlying water from a typical eutrophic lake-Taihu Lake. Then from a sediment-water simulation system, we demonstrated that eutrophic waters were able to methylate Hg spontaneously, and that sediment is the major Hg sink in the system. After the addition of HgCl2 solution (approximately 1 mg L-1 in the slurry), MeHg concentrations in the sediment increased by 11.7 times after 48 h. The subsequent column experiments proved that O2 nanobubbles could significantly decrease the MPA of surface sediment, by up to 48%. Furthermore, we found that O2 nanobubbles could remediate anoxia mainly by increasing dissolved oxygen (from 0 to 2.1 mg L-1), oxidation-reduction potentials (by 37% on average), and sulfate (by 31% on average) in the overlying water. In addition, O2 nanobubbles could also help decrease organic matter concentration, as was revealed by the decline of dissolved organic carbon in the overlying water (by up to 57%) and total organic carbon in surface sediment (by up to 37%). The remediation of anoxia and reduction of organic matter could contribute to the decrease of hgcA gene abundance (by up to 86%), and thus result in the reduction of MPA after the addition of O2 nanobubbles. This study revealed the risk of MeHg production in case Hg pollution occurs in eutrophic waters and proposed a feasible solution for MeHg remediation.
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Affiliation(s)
- Xiaonan Ji
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Chengbin Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China
| | - Gang Pan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China; Beijing Advanced Science and Innovation Center, Chinese Academy of Sciences, Beijing, 101407, PR China; Center of Integrated Water-Energy-Food Studies (iWEF), School of Animal, Rural, and Environmental Sciences, Nottingham Trent University, Brackenhurst Campus, NG25 0QF, UK.
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25
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Crea F, De Stefano C, Irto A, Lando G, Materazzi S, Milea D, Pettignano A, Sammartano S. Understanding the Solution Behavior of Epinephrine in the Presence of Toxic Cations: A Thermodynamic Investigation in Different Experimental Conditions. Molecules 2020; 25:E511. [PMID: 31991662 PMCID: PMC7037007 DOI: 10.3390/molecules25030511] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/16/2020] [Accepted: 01/21/2020] [Indexed: 11/16/2022] Open
Abstract
The interactions of epinephrine ((R)-(-)-3,4-dihydroxy-α-(methylaminomethyl)benzyl alcohol; Eph-) with different toxic cations (methylmercury(II): CH3Hg+; dimethyltin(IV): (CH3)2Sn2+; dioxouranium(VI): UO22+) were studied in NaClaq at different ionic strengths and at T = 298.15 K (T = 310.15 K for (CH3)2Sn2+). The enthalpy changes for the protonation of epinephrine and its complex formation with UO22+ were also determined using isoperibolic titration calorimetry: HHL = -39 ± 1 kJ mol-1, HH2L = -67 ± 1 kJ mol-1 (overall reaction), HML = -26 ± 4 kJ mol-1, and HM2L2(OH)2 = 39 ± 2 kJ mol-1. The results were that UO22+ complexation by Eph- was an entropy-driven process. The dependence on the ionic strength of protonation and the complex formation constants was modeled using the extended Debye-Hückel, specific ion interaction theory (SIT), and Pitzer approaches. The sequestering ability of adrenaline toward the investigated cations was evaluated using the calculation of pL0.5 parameters. The sequestering ability trend resulted in the following: UO22+ >> (CH3)2Sn2+ > CH3Hg+. For example, at I = 0.15 mol dm-3 and pH = 7.4 (pH = 9.5 for CH3Hg+), pL0.5 = 7.68, 5.64, and 2.40 for UO22+, (CH3)2Sn2+, and CH3Hg+, respectively. Here, the pH is with respect to ionic strength in terms of sequestration.
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Affiliation(s)
- Francesco Crea
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, V.le F. Stagno d’Alcontres, 31, I-98166 Messina, Italy; (C.D.S.); (A.I.); (G.L.); (D.M.); (S.S.)
| | - Concetta De Stefano
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, V.le F. Stagno d’Alcontres, 31, I-98166 Messina, Italy; (C.D.S.); (A.I.); (G.L.); (D.M.); (S.S.)
| | - Anna Irto
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, V.le F. Stagno d’Alcontres, 31, I-98166 Messina, Italy; (C.D.S.); (A.I.); (G.L.); (D.M.); (S.S.)
| | - Gabriele Lando
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, V.le F. Stagno d’Alcontres, 31, I-98166 Messina, Italy; (C.D.S.); (A.I.); (G.L.); (D.M.); (S.S.)
| | - Stefano Materazzi
- Dipartimento di Chimica, Università “La Sapienza” di Roma, Piazzale A. Moro 5, I-00185 Rome, Italy;
| | - Demetrio Milea
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, V.le F. Stagno d’Alcontres, 31, I-98166 Messina, Italy; (C.D.S.); (A.I.); (G.L.); (D.M.); (S.S.)
| | - Alberto Pettignano
- Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, V.le delle Scienze, ed. 17, I-90128 Palermo, Italy;
| | - Silvio Sammartano
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, V.le F. Stagno d’Alcontres, 31, I-98166 Messina, Italy; (C.D.S.); (A.I.); (G.L.); (D.M.); (S.S.)
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26
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Cheng L, Wang L, Geng Y, Wang N, Mao Y, Cai Y. Occurrence, speciation and fate of mercury in the sewage sludge of China. Ecotoxicol Environ Saf 2019; 186:109787. [PMID: 31629907 DOI: 10.1016/j.ecoenv.2019.109787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/05/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
Municipal sewage has been identified to be an important source of mercury (Hg) to the environment. However, as the major sink of sewage-borne Hg, sewage sludge (SS) remains unresolved in terms of the occurrence status of Hg species. We presented here, a nation-wide survey on the speciation of Hg in SS of China. Total Hg (THg) and methylmercury (MeHg) were detected in all SS samples, within ranges of 0.4-12.4 mg/kg and 0.1-27.0 μg/kg, respectively. Sludge-borne Hg mainly occurred in the mercury sulfide and organo-chelated phases, with only tiny portions occurring as soluble Hg. The mass loadings of sludge-borne THg and MeHg in China for year 2016 were estimated to be 12.2 metric tons and 19.9 kg, respectively. Landfill was the most important sink of sludge-borne Hg, followed by incineration, land application, and building materials.
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Affiliation(s)
- Liu Cheng
- School of Chemical & Environmental Engineering, Anyang Institute of Technology, Anyang, 455000, China; School of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
| | - Li Wang
- School of Chemical & Environmental Engineering, Anyang Institute of Technology, Anyang, 455000, China
| | - Yuanmeng Geng
- School of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
| | - Ning Wang
- School of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
| | - Yuxiang Mao
- School of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454000, China.
| | - Yong Cai
- Research Center for Eco-Environmental Science, Chinese Academy of Science, Beijing, 100085, China
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27
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Sharma Ghimire P, Tripathee L, Zhang Q, Guo J, Ram K, Huang J, Sharma CM, Kang S. Microbial mercury methylation in the cryosphere: Progress and prospects. Sci Total Environ 2019; 697:134150. [PMID: 32380618 DOI: 10.1016/j.scitotenv.2019.134150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) is one of the most toxic heavy metals, and its cycle is mainly controlled by oxidation-reduction reactions carried out by photochemical or microbial process under suitable conditions. The deposition and accumulation of methylmercury (MeHg) in various ecosystems, including the cryospheric components such as snow, meltwater, glaciers, and ice sheet, and subsequently in the food chain pose serious health concerns for living beings. Unlike the abundance of knowledge about the processes of MeHg production over land and oceans, little is known about the sources and production/degradation rate of MeHg in cryosphere systems. In addition, processes controlling the concentration of Hg and MeHg in the cryosphere remains poorly understood, and filling this scientific gap has been challenging. Therefore, it is essential to study and review the deposition and accumulation by biological, physical, and chemical mechanisms involved in Hg methylation in the cryosphere. This review attempts to address knowledge gaps in understanding processes, especially biotic and abiotic, applicable for Hg methylation in the cryosphere. First, we focus on the variability in Hg concentration and mechanisms of Hg methylation, including physical, chemical, microbial, and biological processes, and transportation in the cryosphere. Then, we elaborate on the mechanism of redox reactions and biotic and abiotic factors controlling Hg methylation and biogeochemistry of Hg in the cryosphere. We also present possible mechanisms of Hg methylation with an emphasis on microbial transformation and molecular function to understand variability in Hg concentration in the cryosphere. Recent advancements in the genetic and physicochemical mechanisms of Hg methylation are also presented. Finally, we summarize and propose a method to study the unsolved issues of Hg methylation in the cryosphere.
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Affiliation(s)
- Prakriti Sharma Ghimire
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal
| | - Lekhendra Tripathee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal.
| | - Qianggong Zhang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100085, China
| | - Junming Guo
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China
| | - Kirpa Ram
- Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi, India
| | - Jie Huang
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100085, China; Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Chhatra Mani Sharma
- Himalayan Environment Research Institute (HERI), Kathmandu, Nepal; Central Department of Environmental Science, Tribhuvan University, Kathmandu, Nepal
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100085, China.
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28
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Wang X, Seelen EA, Mazrui NM, Kerns P, Suib SL, Zhao J, Mason RP. The interaction of mercury and methylmercury with chalcogenide nanoparticles. Environ Pollut 2019; 255:113346. [PMID: 31627051 DOI: 10.1016/j.envpol.2019.113346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/30/2019] [Accepted: 10/03/2019] [Indexed: 06/10/2023]
Abstract
Mercury (Hg) and methylmercury (CH3Hg) bind strongly to micro and nano (NP) particles and this partitioning impacts their fate and bioaccumulation into food webs, and, as a result, potential human exposure. This partitioning has been shown to influence the bioavailability of inorganic Hg to methylating bacteria, with NP-bound Hg being more bioavailable than particulate HgS, or organic particulate-bound Hg. In this study we set out to investigate whether the potential interactions between dissolved ionic Hg (HgII) and CH3Hg and NPs was due to incorporation of Hg into the core of the cadmium selenide and sulfide (CdSe; CdS) nanoparticles (metal exchange or surface precipitation), or due purely to surface interactions. The interaction was assessed based on the quenching of the fluorescence intensity and lifetime observed during HgII or CH3Hg titration experiments of these NP solutions. Additional analysis using inductively coupled plasma mass spectrometry of CdSe NPs and the separated solution, obtained after HgII additions, showed that there was no metal exchange, and X-ray photoelectron spectroscopy confirmed this and further indicated that the Hg was bound to cysteine, the NP capping agent. Our study suggests that Hg and CH3Hg adsorbed to the surfaces of NPs would have different bioavailability for release into water or to (de)methylating organisms or for bioaccumulation, and provides insights into the behavior of Hg in the environment in the presence of natural or manufactured NPs.
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Affiliation(s)
- Xudong Wang
- Department of Chemistry, University of Connecticut, 55 North Eagleville Rd., Storrs, USA
| | - Emily A Seelen
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| | - Nashaat M Mazrui
- Department of Chemistry, University of Connecticut, 55 North Eagleville Rd., Storrs, USA; Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| | - Peter Kerns
- Department of Chemistry, University of Connecticut, 55 North Eagleville Rd., Storrs, USA
| | - Steven L Suib
- Department of Chemistry, University of Connecticut, 55 North Eagleville Rd., Storrs, USA; Institute of Materials Science, University of Connecticut, 97 North Eagleville Rd., Storrs, USA
| | - Jing Zhao
- Department of Chemistry, University of Connecticut, 55 North Eagleville Rd., Storrs, USA; Institute of Materials Science, University of Connecticut, 97 North Eagleville Rd., Storrs, USA
| | - Robert P Mason
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA.
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Li D, Xie L, Carvan MJ, Guo L. Mitigative effects of natural and model dissolved organic matter with different functionalities on the toxicity of methylmercury in embryonic zebrafish. Environ Pollut 2019; 252:616-626. [PMID: 31185350 DOI: 10.1016/j.envpol.2019.05.155] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 05/27/2019] [Accepted: 05/30/2019] [Indexed: 06/09/2023]
Abstract
Dissolved organic matter (DOM) occurs ubiquitously in aquatic environments and plays an intrinsic role in altering the chemical speciation and toxicity of methylmercury (MeHg). However, interactions between MeHg and natural DOM remain poorly understood, especially at the functional group level. We report here the mitigative effects of three natural organic matter (NOM) and five model-DOM under different concentrations (0, 1, 3, 10, 30 and 100 mg-C/L) on the toxicity of MeHg in embryonic zebrafish (<4 h post-fertilization, hpf). NOM are those from the Mississippi River, Yukon River, and Suwannee River, while model-DOM include those containing thiosalicylic acid, L-glutathione, dextran, alginic acid, and humic acid. We selected a MeHg concentration (100 n-mol/L) that reduces the survival rate of embryos at 24 hpf by 18% and increases malformations at 72 and 96 hpf. In the presence of DOM, however, the malformation rates induced by MeHg can be mitigated to a different extent depending on DOM concentrations, specific functional groups, and/or specific components. Model DOM with aromatic thiols was the most effective at mitigating the effects of MeHg, followed by L-glutathione, carbohydrates, and humic acid. NOM also mitigated the toxicity of MeHg dependent on their composition and/or effective DOM components as characterized by fluorescence excitation-emission matrix techniques. Specifically, humic-like DOM components are more effective in reducing the MeHg toxicity in the embryonic zebrafish compared to protein-like components. Further studies are needed to elucidate the interactions between DOM and MeHg and the mitigative mechanisms at the molecular level.
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Affiliation(s)
- Dan Li
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E Greenfield Ave., Milwaukee, WI, 53204, USA; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lingtian Xie
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China
| | - Michael J Carvan
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E Greenfield Ave., Milwaukee, WI, 53204, USA
| | - Laodong Guo
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E Greenfield Ave., Milwaukee, WI, 53204, USA.
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30
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Liao W, Wang G, Zhao W, Zhang M, Wu Y, Liu X, Li K. Change in mercury speciation in seafood after cooking and gastrointestinal digestion. J Hazard Mater 2019; 375:130-137. [PMID: 31054530 DOI: 10.1016/j.jhazmat.2019.03.093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 02/19/2019] [Accepted: 03/20/2019] [Indexed: 06/09/2023]
Abstract
Mercury (Hg) is readily bioaccumulated in seafood, a common ingredient in indigenous cuisines throughout the world. This study investigates Hg speciation in cooked seafood after gastric and intestinal digestion. The results showed that the removal of Hg by washing was negligible. Additionally, the results of our calculations regarding the mass balance of Hg concentration indicated that cooking reduced Hg mainly by means of volatilization and that Hg2+ was more readily reduced than MeHg. Moreover, cooking lowered the bioaccessibility of Hg in seafood: the reduced percent of bioaccessible Hg2+ after cooking ranged from 2 to 35% (on average, 16%). The corresponding numbers were slightly lower compared with those for MeHg (on average, 19%). Furthermore, there might be a chemical transformation of Hg during in vitro gastrointestinal digestion. The results of in vivo tests in laboratory mice suggested that methylation of Hg mainly took place in the gastric tract, whereas demethylation of Hg occurred primarily during intestinal digestion. These findings indicate that the bioaccessibility of Hg2+ and MeHg was not only related to their initial concentrations in the food samples, but also that further studies on the mechanisms of Hg demethylation and methylation during gastrointestinal digestion are essential for more realistic risk assessments.
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Affiliation(s)
- Wen Liao
- National Key Laboratroty of Water Environment Simulation and Polltion Control, South China Institute of Environment Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510665, China; Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510655, China; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guang Wang
- National Key Laboratroty of Water Environment Simulation and Polltion Control, South China Institute of Environment Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510665, China; Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510655, China.
| | - Wenbo Zhao
- National Key Laboratroty of Water Environment Simulation and Polltion Control, South China Institute of Environment Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510665, China; Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510655, China
| | - Meng Zhang
- National Key Laboratroty of Water Environment Simulation and Polltion Control, South China Institute of Environment Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510665, China; Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510655, China; College of Life Sciences, Hebei University, Baoding, 071002, China
| | - Ye Wu
- National Key Laboratroty of Water Environment Simulation and Polltion Control, South China Institute of Environment Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510665, China; Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510655, China
| | - Xiaowei Liu
- National Key Laboratroty of Water Environment Simulation and Polltion Control, South China Institute of Environment Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510665, China; Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510655, China
| | - Kaiming Li
- National Key Laboratroty of Water Environment Simulation and Polltion Control, South China Institute of Environment Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510665, China; Guangdong Key Laboratory of Water and Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510655, China
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31
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Liu J, Wang J, Ning Y, Yang S, Wang P, Shaheen SM, Feng X, Rinklebe J. Methylmercury production in a paddy soil and its uptake by rice plants as affected by different geochemical mercury pools. Environ Int 2019; 129:461-469. [PMID: 31154148 DOI: 10.1016/j.envint.2019.04.068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/15/2019] [Accepted: 04/28/2019] [Indexed: 06/09/2023]
Abstract
The formation of neurotoxic methylmercury (MeHg) in paddy fields and its accumulation by rice plants is of high environmental concern. The contribution of different geochemical mercury (Hg) pools in paddy soils to MeHg production and its accumulation by rice seedlings is not well-studied up to now. Therefore, we investigated the impact of different inorganic Hg forms, including HgCl2, nano-particulated HgS (nano-HgS), Hg bound with dissolved organic matter (Hg-DOM), β-HgS, and α-HgS, at levels of 5 mg Hg/kg soil and 50 mg Hg/kg soil, on the production of MeHg in the soil during rice growing season. Further, we studied the uptake of MeHg by the roots, stalks, leaves, and grains of rice in the tillering, panicle formation, and ripening growth stages, and compared these treatments to a non-polluted soil (control). MeHg contents in HgCl2 polluted soil were the highest, and were 13.5 times and 36.1 times higher than control in 5 and 50 mg/kg Hg treatments, respectively. MeHg contents in α-HgS, β-HgS, nano-HgS, and Hg-DOM polluted soil were 3.9, 2.6, 2.4, and 1.7 times, and 4.4, 15.1, 6.7, and 10.9 times higher than control in 5 and 50 mg/kg Hg treatments, respectively, suggesting the mobilization and methylation of these Hg complexes. The ratio of MeHg to total Hg in the pore water (indication of methylation potential) in HgCl2 and β-HgS treatments were higher than in Hg-DOM, α-HgS, and nano-HgS treatments. HgCl2 treatment resulted in significantly higher MeHg contents in the root, stalk, leaf, and brown rice than nano-HgS, Hg-DOM, β-HgS, and α-HgS treatments both in 5 and 50 mg/kg Hg polluted soils. Rice grain in HgCl2 treatment showed a potential hazard to human health, as indicated by high health risk index (HRI > 1) of MeHg. Current results improve our understanding of MeHg production in soil polluted with different Hg forms, and the assessment of human health risks from consumption of MeHg-laden rice grain at Hg polluted sites with different Hg forms in soils.
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Affiliation(s)
- Jinling Liu
- School of Earth Sciences, China University of Geosciences, Wuhan 430074, China.
| | - Jianxu Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China.
| | - Yongqiang Ning
- School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Shaochen Yang
- School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Pengcong Wang
- School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Sabry M Shaheen
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; King Abdulaziz University, Faculty of Meteorology, Environment, and Arid Land Agriculture, Department of Arid Land Agriculture, 21589 Jeddah, Saudi Arabia; University of Kafrelsheikh, Faculty of Agriculture, Department of Soil and Water Sciences, 33516 Kafr El-Sheikh, Egypt.
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; University of Sejong, Department of Environment, Energy and Geoinformatics, 98 Gunja-Dong, Guangjin-Gu, Seoul, South Korea.
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Man Y, Yin R, Cai K, Qin C, Wang J, Yan H, Li M. Primary amino acids affect the distribution of methylmercury rather than inorganic mercury among tissues of two farmed-raised fish species. Chemosphere 2019; 225:320-328. [PMID: 30884293 DOI: 10.1016/j.chemosphere.2019.03.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/16/2019] [Accepted: 03/10/2019] [Indexed: 05/25/2023]
Abstract
The distributions of primary amino acids, MeHg and IHg in body tissues of two commonly farm-raised fish species (common carp: Cyprinus carpio; grass carp: Ctenopharyngodon idellus) in Guizhou Province, SW China, were investigated to understand the effects of primary amino acids on MeHg and IHg metabolism in farm-raised fish. The primary amino acids were classified into four groups: (1) essential and polar amino acids; (2) essential and non-polar amino acids; (3) non-essential and polar amino acids; and (4) non-essential and non-polar amino acids. For both fish species, groups (1, 2 and 3) were enriched in muscle and kidney, whereas group (4) was enriched in scale. The two fish species showed low MeHg concentrations (grass carp: 0.5-3.9 ng/g; common carp:1.0-7.4 ng/g) and low MeHg proportions (grass carp: 2-45%; common carp: 6-37%) in their tissues, which are mainly due to the simple food web structures and the fast growth of the farm-raised fish. Positive correlations (r = 0.342 to 0.472; p < 0.01; n = 78) were observed between MeHg and several primary amino acids (cysteine, threonine, phenylalanine, leucine, valine, glutamate serine and tyrosine) in fish tissues, which may be driven by the formation of MeHg-Cys complexes within fish body. However, no significant correlations were observed between IHg and any primary amino acids, indicating the metabolic processes of IHg and MeHg are different. This study advances our understanding that cysteine and its related/derived amino acids may be an important driving force for MeHg distribution and translocation in fish.
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Affiliation(s)
- Yi Man
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou Province, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou Province, China; University of Chinese Academic of Sciences, Beijing, China
| | - Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou Province, China.
| | - Kai Cai
- Guizhou Academy of Tobacco Science, Guiyang, Guizhou Province, China
| | - Chongyang Qin
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou Province, China; University of Chinese Academic of Sciences, Beijing, China
| | - Jianxu Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou Province, China
| | - Haiyu Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou Province, China.
| | - Miling Li
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Wang Y, Yin D, Xiang Y, Xu Q, Zhang C, Xie Q, Wang D. A Review of Studies on the Biogeochemical Behaviors of Mercury in the Three Gorges Reservoir, China. Bull Environ Contam Toxicol 2019; 102:686-694. [PMID: 30859245 DOI: 10.1007/s00128-019-02586-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/02/2019] [Indexed: 06/09/2023]
Abstract
The Three Gorges Reservoir (TGR) is a relatively large reservoir, and its water level management actions produce a widespread water level fluctuation zone (WLFZ), which has characteristics of both terrestrial and aquatic ecosystems. Here, an integrated overview of current knowledge on Hg behaviors in the TGR, especially the WLFZ, as well as exposure risk to local residents was presented. Hg levels in the TGR were comparable with other natural aquatic systems. WLFZ in the TGR was confirmed to be an environment favorable for Hg methylation by enhancing microbial activity, promoting sulfur cycling and increasing the level of low-molecular-weight organic matters. However, elevated fish Hg concentrations did not follow the impoundment of TGR, indicating no obvious reservoir effect, while it is still noteworthy that frequently consuming fish is likely to be a methylmercury (MeHg) exposure pathway for specific populations e.g. fishermen around the TGR.
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Affiliation(s)
- Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, 400715, Chongqing, China
| | - Deliang Yin
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Yuping Xiang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Qinqin Xu
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Cheng Zhang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, 400715, Chongqing, China
| | - Qing Xie
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China.
- Chongqing Key Laboratory of Agricultural Resources and Environment, 400715, Chongqing, China.
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Li H, Zheng D, Yang J, Wu C, Zhang S, Li H, Ma H. Salinity and redox conditions affect the methyl mercury formation in sediment of Suaeda heteroptera wetlands of Liaoning province, Northeast China. Mar Pollut Bull 2019; 142:537-543. [PMID: 31232335 DOI: 10.1016/j.marpolbul.2019.03.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/28/2019] [Accepted: 03/31/2019] [Indexed: 06/09/2023]
Abstract
Using a laboratory simulation experiment, we studied the trend of change in methylmercury (MeHg) content of sediments in response to the changing salinity of flooding water (deionized water, 0.5%, 1.0%, 1.5%, and 2.0%) and sulfate-reducing bacteria (SRB) content for both the surface layer (0-10 cm) and the bottom layer (10-20 cm) of Suaeda heteroptera wetland sediments in the Liaohe estuary under anaerobic and aerobic conditions, respectively. The results showed that under AAC (anaerobic conditions), the MeHg content in the surface and bottom sediment layers increased first and then decreased over time and was highest at the 14th day. In contrast, under AC (aerobic conditions), the MeHg content in sediments of both layers increased slowly with increasing test time. The MeHg content in sediments increased first and then decreased with rising salinity and was highest at a salinity of 1.0%. Among the samples collected at different experimental stages, the SRB content in the sediments showed a decreasing trend with rising flooding salinity under AAC and AC. The MeHg and SRB contents were higher under anaerobic conditions than under aerobic conditions. Linear fitting results showed that there was no linear correlation between MeHg contents and SRB quantities in surface and bottom sediments under AAC and AC (R2 < 0.1). Collectively, these results suggest an important role for flooding salinity and anaerobic-aerobic conditions in the production of MeHg in S. heteroptera wetlands of the Liaohe estuary, and may predict the ecological risk of methylmercury according to the change of salinity.
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Affiliation(s)
- Hang Li
- Environmental College, Shenyang University, Shenyang 110044, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Ministry of Education, Shenyang University, Shenyang 110044, China
| | - Dongmei Zheng
- Environmental College, Shenyang University, Shenyang 110044, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Ministry of Education, Shenyang University, Shenyang 110044, China.
| | - Jisong Yang
- Environmental College, Shenyang University, Shenyang 110044, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Ministry of Education, Shenyang University, Shenyang 110044, China
| | - Chenghao Wu
- Environmental College, Shenyang University, Shenyang 110044, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Ministry of Education, Shenyang University, Shenyang 110044, China
| | - Shiwei Zhang
- Environmental College, Shenyang University, Shenyang 110044, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Ministry of Education, Shenyang University, Shenyang 110044, China
| | - Huiying Li
- Environmental College, Shenyang University, Shenyang 110044, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Ministry of Education, Shenyang University, Shenyang 110044, China
| | - Huanchi Ma
- Environmental College, Shenyang University, Shenyang 110044, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Ministry of Education, Shenyang University, Shenyang 110044, China
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Tang W, Su Y, Gao Y, Zhong H. Effects of Farming Activities on the Biogeochemistry of Mercury in Rice-Paddy Soil Systems. Bull Environ Contam Toxicol 2019; 102:635-642. [PMID: 31053868 DOI: 10.1007/s00128-019-02627-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
The biogeochemistry of mercury (Hg) in rice-paddy soil systems raises concerns, given that (1) the redox potential in paddy soil favors Hg methylation and (2) rice plants have a strong ability to accumulate methylmercury (MeHg), making rice an important source for MeHg exposure to humans. Therefore, all factors affecting the behavior of Hg in rice-paddy soils might impact Hg accumulation in rice, with its subsequent potential risks. As a typical wetland, paddy soils are managed by humans and affected by anthropogenic activities, such as agronomic measures, which would impact soil properties and thus Hg biogeochemistry. In this paper, we reviewed recent advances in the effects of farming activities including water management, fertilizer application and rotation on Hg biogeochemistry, trying to elucidate the factors controlling Hg behavior and thus the ecological risks in rice-paddy soil systems. This review might provide new thoughts on Hg remediation and suggest avenues for further studies.
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Affiliation(s)
- Wenli Tang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, China
| | - Yao Su
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, China
| | - Yuxi Gao
- State Environmental Protection Engineering Center for Mercury Pollution Prevention and Control, Laboratory of Metallomics and Nanometallomics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, China.
- Environmental and Life Sciences Program (EnLS), Trent University, Peterborough, ON, Canada.
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Rutkowska M, Bajger-Nowak G, Kowalewska D, Bzoma S, Kalisińska E, Namieśnik J, Konieczka P. Methylmercury and total mercury content in soft tissues of two bird species wintering in the Baltic Sea near Gdansk, Poland. Chemosphere 2019; 219:140-147. [PMID: 30543952 DOI: 10.1016/j.chemosphere.2018.11.162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 11/14/2018] [Accepted: 11/25/2018] [Indexed: 06/09/2023]
Abstract
Of the various forms of Hg occurring in nature, (mono) methylmercury (MeHg) is an especially toxic form and practically all forms of Hg can be converted into MeHg as a result of natural processes. Total mercury (THg) and MeHg were determined in tissues of two piscivorous birds: razorbill Alca torda and black-throated loon Gavia arctica to provide baseline data on current mercury concentrations for liver, kidneys and pectoral muscle mercury concentrations of birds which winter on the south Baltic Sea coast. Intra and inter-specific comparisons were carried out. The study is conducted between winter and autumn and the distributions of mercury in tissues were compared with data in other studies. The following paper contains discussion of the results based on the statistical analysis and ecology aspect. The highest average Hg content was in the liver (loon ≈ 3.86 mg kg-1 dw; razorbill ≈ 1.57 mg kg-1 dw), then in the kidneys (loon ≈ 3.14 mg kg-1 dw; razorbill ≈ 1.53 mg kg-1 dw) and the lowest concentrations were in pectoral muscles (loon ≈ 1.97 mg kg-1 dw; razorbill ≈ 0.67 mg kg-1 dw).
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Affiliation(s)
- Małgorzata Rutkowska
- Gdańsk University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, 11/12 G. Narutowicza Street, 80-233 Gdańsk, Poland.
| | - Gabriela Bajger-Nowak
- Gdańsk University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, 11/12 G. Narutowicza Street, 80-233 Gdańsk, Poland
| | - Diana Kowalewska
- Gdańsk University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, 11/12 G. Narutowicza Street, 80-233 Gdańsk, Poland
| | - Szymon Bzoma
- Waterbird Research Group KULING, 34/7 Świerkowa Street, 81-526 Gdynia, Poland.
| | - Elżbieta Kalisińska
- Pomeranian Medical University, Department of Biology and Medical Parasitology, 72 Powstancow Wielkopolskich Street, 70-411 Szczecin, Poland.
| | - Jacek Namieśnik
- Gdańsk University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, 11/12 G. Narutowicza Street, 80-233 Gdańsk, Poland
| | - Piotr Konieczka
- Gdańsk University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, 11/12 G. Narutowicza Street, 80-233 Gdańsk, Poland
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Zhang J, Wu S, Xu Z, Wang M, Man YB, Christie P, Liang P, Shan S, Wong MH. The role of sewage sludge biochar in methylmercury formation and accumulation in rice. Chemosphere 2019; 218:527-533. [PMID: 30500713 DOI: 10.1016/j.chemosphere.2018.11.090] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/20/2018] [Accepted: 11/12/2018] [Indexed: 06/09/2023]
Abstract
Methylmercury (MeHg) can accumulate in rice and this has been demonstrated to be an important human MeHg exposure pathway. How to reduce MeHg concentrations in rice grains has therefore become a very important public health issue. Previous studies have investigated the role of plant biochars on Hg bioavailability in soils but knowledge of the influence of sewage sludge biochars (SSB) on MeHg formation and bioaccumulation in different soils is lacking. In the present study, SSB was applied to two Hg-contaminated soils, one acid and the other calcareous, in an attempt to stabilize MeHg in the soil and further mitigate MeHg accumulation in rice grains. The results indicate that the presence of SSB may promote Hg methylation in an acid soil. Moreover, MeHg concentrations increased gradually during rice growth, perhaps due to the release of root exudates. SSB can inhibit both MeHg and total Hg (THg) accumulation in different rice tissues. Both MeHg and THg decreased in the rice grains by up to 73.4 and 81.9%, respectively. However, the inhibitory effect was less pronounced in a calcareous soil. This study further demonstrates that biochar application can inhibit MeHg accumulation in soils despite the promotion of MeHg formation in soil by SSB application. However, an effect of biochar on MeHg accumulation was observed only in the acid soil. These results are useful in managing applications of biochars to Hg-contaminated paddy fields.
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Affiliation(s)
- Jin Zhang
- Zhejiang Province Key Laboratory of Recycling and Eco-Treatment of Waste Biomass, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China
| | - Shengchun Wu
- Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Zhentao Xu
- Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Minyan Wang
- Jiyang College, Zhejiang Agriculture and Forestry University, Zhuji, 311800, China
| | - Yu Bon Man
- Consortium on Health, Environment, Education and Research (CHEER), Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong SAR
| | - Peter Christie
- Zhejiang Province Key Laboratory of Recycling and Eco-Treatment of Waste Biomass, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China
| | - Peng Liang
- Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China.
| | - Shengdao Shan
- Zhejiang Province Key Laboratory of Recycling and Eco-Treatment of Waste Biomass, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China.
| | - Ming Hung Wong
- Consortium on Health, Environment, Education and Research (CHEER), Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong SAR
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Park M, Hong KI, Jin SM, Lee E, Jang WD, Ju SY. Helical Assembly of Flavin Mononucleotides on Carbon Nanotubes as Multimodal Near-IR Hg(II)-Selective Probes. ACS Appl Mater Interfaces 2019; 11:8400-8411. [PMID: 30724070 DOI: 10.1021/acsami.8b18781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The development of novel methods to detect mercury is of paramount importance owing to the impact of this metal on human health and the environment. We observed that flavin mononucleotide (FMN) and its helical assembly with a single-walled carbon nanotube (SWNT) selectively bind Hg2+ arising from HgCl2 and MeHgCl. Absorption spectroscopic studies show that FMN preferentially forms a 2:1 rather than a 1:1 complex with Hg2+ at high FMN concentrations. On the basis of the analogy to the thymine-Hg-thymine complex, it is proposed that the 2:1 complex between FMN and Hg2+ comprises a Hg-bridged pair of FMN groups, regardless of the presence of SWNT. Upon addition of as little as a few hundred nanomoles of Hg2+, both FMN and FMN-SWNT exhibit absorption and photoluminescence (PL) changes. Moreover, FMN-SWNT displays simultaneous multiple sigmoidal changes in PL of SWNT tubes having different chiral vectors. Assessment of binding affinities using the Hill equation suggests that 2:1 and 1:1 complexes form between Hg2+ and FMN groups on the FMN-SWNT. Theoretical calculations indicate that optical changes of the FMN-SWNT originate from Hg-mediated conformational changes occurring on the helical array of FMN on the SWNT. High-resolution transmission electron microscopy revealed that the presence of Hg2+ in complexes with the FMN-SWNT enables visualization of helical periodic undulation of FMN groups along SWNT without the need for staining. Circular dichroism (CD) study revealed that FMN-SWNT whose CD signal mainly originates from FMN decreases dichroic bands upon the addition of Hg2+ owing to the formation of a centrosymmetric FMN-Hg-FMN triad on SWNT. The binding mode specificity and multimodal changes observed in response to Hg2+ ions suggest that systems based on FMN-SWNT can serve as in vivo NIR beacons for the detection of various mercury derivatives.
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Affiliation(s)
- Minsuk Park
- Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seodaemun-Gu, Seoul 03722 , Republic of Korea
| | - Kyeong-Im Hong
- Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seodaemun-Gu, Seoul 03722 , Republic of Korea
| | - Seon-Mi Jin
- Graduate School of Analytical Science and Technology , Chungnam National University , Daejeon 34134 , Republic of Korea
| | - Eunji Lee
- School of Materials Science and Engineering , Gwangju Institute of Science and Technology (GIST) , Gwangju 61005 , Republic of Korea
| | - Woo-Dong Jang
- Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seodaemun-Gu, Seoul 03722 , Republic of Korea
| | - Sang-Yong Ju
- Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seodaemun-Gu, Seoul 03722 , Republic of Korea
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Xie M, Zhang C, Liao X, Fan Z, Xie X, Huang C. Mechanisms of radical-initiated methylmercury degradation in soil with coexisting Fe and Cu. Sci Total Environ 2019; 652:52-58. [PMID: 30359801 DOI: 10.1016/j.scitotenv.2018.10.178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/12/2018] [Accepted: 10/12/2018] [Indexed: 06/08/2023]
Abstract
Methylmercury (MeHg) is a toxic compound. It forms mainly in reducing environments, and then degrades through biogeochemical processes. Photodegradation and microorganism degradation of MeHg are among the processes that have been reported. However, little attention has been focused on the abiotic degradation of MeHg in soil/sediment without light. In our study, the percent MeHg of total Hg in Guangzhou soil in southern China was found to be variable and exhibited a significant negative correlation with the content of Fe or Cu where annite (KFe2+3(AlSi3O10)(OH)2), a Fe-bearing mineral, was identified. To understand the mechanisms of radical-initiated MeHg degradation by Fe/Cu-containing components, batch experiments were done. Results showed that annite in the soils could activate O2 to generate OH and O2- and facilitate MeHg degradation under oxic conditions. Meanwhile, Cu components in the soil further enhanced the production of O2-, and was oxidized to Cu(III) promoting degradation of MeHg directly. These findings help us understand that the distribution of MeHg in soil depends on not only external pollution sources, but also on biogeochemical processes in subsurface environments.
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Affiliation(s)
- Mengying Xie
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China
| | - Caixiang Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China.
| | - Xiaoping Liao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China
| | - Zenghui Fan
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China
| | - Xinmo Xie
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China
| | - Changsheng Huang
- Wuhan Center of China Geological Survey, Wuhan 430205, Hubei, PR China
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Beutel MW, Dent SR, Newcombe RL, Möller G. Mercury removal from municipal secondary effluent with hydrous ferric oxide reactive filtration. Water Environ Res 2019; 91:132-143. [PMID: 30735297 DOI: 10.1002/wer.1007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 09/23/2018] [Indexed: 06/09/2023]
Abstract
This study evaluated the ability of hydrous ferric oxide reactive filtration (HFO-RF) to remove mercury (Hg) from municipal secondary effluent at four study sites. Pilot HFO-RF systems (136 m3 /day) at two sites demonstrated total Hg concentration removal efficiencies of 96% (inflow/outflow mean total Hg: 43.6/1.6 ng/L) and 80% (4.2/0.8 ng/L). A lightly loaded medium-scale HFO-RF system (950 m3 /day) had a concentration removal efficiency of 53% (0.98/0.46 ng/L) and removed 0.52 mg/day of total Hg and 2.2 μg/day of methyl-Hg. A full-scale HFO-RF system (11,400 m3 /day) yielded a total Hg concentration removal efficiency of 97% (87/2.7 ng/L) and removed an estimated 0.36 kg/year of Hg. Results suggest that the quality of secondary effluent, including dissolved organic matter content, affects achievable minimum total Hg concentrations in effluent from HFO-RF systems. Low HFO-RF effluent concentrations (<1 ng/L) can be expected when treating secondary effluent from suspended-growth biological treatment systems. PRACTITIONER POINTS: Trace levels of mercury in municipal secondary effluent can negatively impact receiving waters. Hydrous ferric oxide reactive filtration (HFO-RF) can remove mercury from municipal secondary effluent to levels below the Great Lakes Initiative discharge standard of 1.3 ng/L. Mercury removal to low concentrations (< 1 ng/L) using HFO-RF appears to be associated with secondary effluents with low dissolved organic matter content. HFO-RF can also remove total phosphorus and turbidity to low concentrations.
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Affiliation(s)
- Marc W Beutel
- Department of Civil and Environmental Engineering, University of California Merced, Merced, California
| | - Stephen R Dent
- Miles Community College, Miles City, Montana
- Hydrometrics, Inc., Billings, Montana
| | | | - Gregory Möller
- Department of Biological Engineering, School of Food Science, University of Idaho, Moscow, Idaho
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Pedro S, Fisk AT, Ferguson SH, Hussey NE, Kessel ST, McKinney MA. Limited effects of changing prey fish communities on food quality for aquatic predators in the eastern Canadian Arctic in terms of essential fatty acids, methylmercury and selenium. Chemosphere 2019; 214:855-865. [PMID: 30317166 DOI: 10.1016/j.chemosphere.2018.09.167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 09/24/2018] [Accepted: 09/28/2018] [Indexed: 06/08/2023]
Abstract
We determined concentrations of eicosapentaenoic and docosahexaenoic acids (EPA + DHA), Σomega-3, polyunsaturated fatty acids (ΣPUFA), selenium, methylmercury, and selenium:methylmercury (Se:Hg) ratios in native and northward-redistributing sub-Arctic marine fish and invertebrates from low, mid-, and high Canadian Arctic latitudes. There was no clear latitudinal trend in nutrient or contaminant concentrations. Among species, EPA + DHA concentrations in native Arctic cod (Boreogadus saida) were similar to concentrations in sub-Arctic capelin (Mallotus villosus) and sand lance (Ammodytes spp.) (444-658 mg.100 g-1), and higher than in most other species. Concentrations of EPA + DHA were related to lipid content, but to a greater extent for higher trophic position species (R2 = 0.83) than for species at lower trophic positions (R2 = 0.61). Selenium concentrations were higher in sand lance (1.15 ± 0.16 μg g-1) than in all other species (0.30-0.69 μg g-1), which was significantly, but weakly, explained by more pelagic feeding in sand lance. Methylmercury concentrations were similar (and Se:Hg ratios were higher) in capelin, sand lance, and Arctic cod (0.01-0.03 μg g-1 wet weight (ww)) and lower than in other prey (0.12-0.26 μg g-1 ww), which was significantly explained by the smaller size of these species and more pelagic feeding habits than other fish. These results suggested that a shift in prey fish composition from Arctic cod to capelin and/or sand lance is unlikely to reduce the food quality of the prey available to marine predators at least with respect to concentrations of essential fatty acids, selenium, and Se:Hg ratios.
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Affiliation(s)
- Sara Pedro
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA.
| | - Aaron T Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Steven H Ferguson
- Fisheries and Oceans Canada, Central and Arctic Region, Winnipeg, MB R3T 2N6, Canada
| | - Nigel E Hussey
- Department of Biological Sciences, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Steven T Kessel
- Daniel P. Haerther Center for Conservation and Research, John G. Shedd Aquarium, Chicago, IL 60605, USA
| | - Melissa A McKinney
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA; Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.
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Strohmidel P, Sperling M, Karst U. Investigations on the binding of ethylmercury from thiomersal to proteins in influenza vaccines. J Trace Elem Med Biol 2018; 50:100-104. [PMID: 30262265 DOI: 10.1016/j.jtemb.2018.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/07/2018] [Accepted: 06/15/2018] [Indexed: 01/01/2023]
Abstract
This study investigates the binding of ethylmercury (EtHg+) released from the preservative thiomersal by hydrolysis to proteins in influenza vaccines via ultrafiltration and subsequent total reflection x-ray fluorescence (TXRF) analysis as well as size exclusion chromatography (SEC) hyphenated to inductively coupled plasma-mass spectrometry (ICP-MS). Binding of EtHg+ to the protein fraction was shown by means of ultrafiltration and TXRF in a qualitative matter. SEC/ICP-MS was applied to gain more information about the molecular weight of the bound protein and quantitative information. First experiments showed the necessity of a rinsing step during elution with a thiol-containing compound to prevent unspecific binding or mercury species to the chromatographic system. Adduct formation of EtHg+ and a high-molecular compound could be observed for different concentrations of EtHg+ applied. The mercury-containing fraction was larger than 133 kDa, indicating binding to hemagglutinin, which is the active ingredient in influenza vaccines. The applied SEC/ICP-MS method allowed for external calibration with EtHg+ and a binding of 141 μg L-1 Hg was shown for a vaccine solution that was incubated with EtHg+ (25 mg L-1 Hg).
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Affiliation(s)
- Philipp Strohmidel
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstr. 28/30, 48149 Münster, Germany
| | - Michael Sperling
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstr. 28/30, 48149 Münster, Germany; European Virtual Institute for Speciation Analysis (EVISA), Mendelstr. 11, 48149 Münster, Germany
| | - Uwe Karst
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstr. 28/30, 48149 Münster, Germany.
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Zhao JY, Ye ZH, Zhong H. Rice root exudates affect microbial methylmercury production in paddy soils. Environ Pollut 2018; 242:1921-1929. [PMID: 30072222 DOI: 10.1016/j.envpol.2018.07.072] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 07/16/2018] [Accepted: 07/16/2018] [Indexed: 06/08/2023]
Abstract
Microbial methylmercury (MeHg) production in contaminated soil-rice systems and its accumulation in rice pose health risks to consumers, especially those in Asia. However, the mechanism responsible for microbial MeHg production in paddy soils is far from clear. While previous studies examined the effect of soil and microbial factors on soil MeHg levels, in this work we explored the impact of rice cultivation itself on microbial MeHg production, focusing on the root exudate organic matter as a potential source of electron donors for microbial methylators. Effects of the cultivation of two rice cultivars, Heigu246 (H-rice) and Neiwuyou8015 (N-rice), on MeHg production in soils were therefore investigated in pot and batch incubation experiments. Soil MeHg levels measured in H-rice treatment during the heading and harvest stages were 18-49% higher than in the control and 23-108% higher than in N-rice treatment. Consequently, MeHg levels in grain, straw, and root were 38%, 81%, and 40% higher in H-rice than those in N-rice, which was mainly attributed to cultivar-specific MeHg production in soils. Results of the batch experiments suggested that root exudate organic matter could be responsible for MeHg production in soils during rice cultivation, by increasing the abundances of potential microbial methylators. For instance, root exudate organic matter increased copy numbers of Hg methylation genes (hgcA) in soils 4.1-fold. Furthermore, the 211% higher concentration of acetate (a key electron donor for microbial methylators) in the root exudate of H-rice could account for the higher MeHg production under H-rice than N-rice cultivation. Our results suggest that root exudate organic matter, especially acetate, as its key component, contributes to the elevated soil MeHg concentrations during rice cultivation. The proposed mechanism provides new insights into the elevated risk of MeHg production in contaminated soil-rice systems, as well as cultivar-specific MeHg bioaccumulation.
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Affiliation(s)
- Jia-Yin Zhao
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Zhi-Hong Ye
- State Key Laboratory for Bio-control and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, 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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Bravo AG, Kothawala DN, Attermeyer K, Tessier E, Bodmer P, Ledesma JLJ, Audet J, Casas-Ruiz JP, Catalán N, Cauvy-Fraunié S, Colls M, Deininger A, Evtimova VV, Fonvielle JA, Fuß T, Gilbert P, Herrero Ortega S, Liu L, Mendoza-Lera C, Monteiro J, Mor JR, Nagler M, Niedrist GH, Nydahl AC, Pastor A, Pegg J, Gutmann Roberts C, Pilotto F, Portela AP, González-Quijano CR, Romero F, Rulík M, Amouroux D. The interplay between total mercury, methylmercury and dissolved organic matter in fluvial systems: A latitudinal study across Europe. Water Res 2018; 144:172-182. [PMID: 30029076 DOI: 10.1016/j.watres.2018.06.064] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/27/2018] [Accepted: 06/28/2018] [Indexed: 05/16/2023]
Abstract
Large-scale studies are needed to identify the drivers of total mercury (THg) and monomethyl-mercury (MeHg) concentrations in aquatic ecosystems. Studies attempting to link dissolved organic matter (DOM) to levels of THg or MeHg are few and geographically constrained. Additionally, stream and river systems have been understudied as compared to lakes. Hence, the aim of this study was to examine the influence of DOM concentration and composition, morphological descriptors, land uses and water chemistry on THg and MeHg concentrations and the percentage of THg as MeHg (%MeHg) in 29 streams across Europe spanning from 41°N to 64 °N. THg concentrations (0.06-2.78 ng L-1) were highest in streams characterized by DOM with a high terrestrial soil signature and low nutrient content. MeHg concentrations (7.8-159 pg L-1) varied non-systematically across systems. Relationships between DOM bulk characteristics and THg and MeHg suggest that while soil derived DOM inputs control THg concentrations, autochthonous DOM (aquatically produced) and the availability of electron acceptors for Hg methylating microorganisms (e.g. sulfate) drive %MeHg and potentially MeHg concentration. Overall, these results highlight the large spatial variability in THg and MeHg concentrations at the European scale, and underscore the importance of DOM composition on mercury cycling in fluvial systems.
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Affiliation(s)
- Andrea G Bravo
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish National Research Council (CSIC), Barcelona, Spain.
| | - Dolly N Kothawala
- Limnology/Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Katrin Attermeyer
- Limnology/Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Emmanuel Tessier
- CNRS/ UNIV PAU & PAYS ADOUR, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Materiaux, UMR5254, MIRA, Pau, France
| | - Pascal Bodmer
- Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany; Chemical Analytics and Biogeochemistry, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - José L J Ledesma
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Joachim Audet
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Núria Catalán
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | | | - Miriam Colls
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | - Anne Deininger
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Vesela V Evtimova
- Department of Aquatic Ecosystems, Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Jérémy A Fonvielle
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Thomas Fuß
- Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; WasserCluster Biological Station Lunz, Lunz am See, Austria
| | - Peter Gilbert
- The Environmental Research Institute, North Highland College, University of Highlands and Islands, Thurso, Scotland, UK
| | - Sonia Herrero Ortega
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Liu Liu
- Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany
| | - Clara Mendoza-Lera
- IRSTEA, UR RiverLy, Centre de Lyon-Villeurbanne, Villeurbanne, Cedex, France
| | - Juliana Monteiro
- Research Centre in Biodiversity and Genetic Resources (CIBIO), University of Porto, Porto, Portugal
| | - Jordi-René Mor
- Catalan Institute for Water Research (ICRA), Girona, Spain; Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona (UB), Barcelona, Spain
| | - Magdalena Nagler
- Microbial Resource Management, Institute of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Georg H Niedrist
- River and Conservation Research, Institute of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Anna C Nydahl
- Limnology/Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Ada Pastor
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | - Josephine Pegg
- Department of Life and Environmental Sciences, Bournemouth University, UK; University Centre Sparsholt, Winchester, UK
| | | | - Francesca Pilotto
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Ana Paula Portela
- Research Centre in Biodiversity and Genetic Resources (CIBIO), University of Porto, Porto, Portugal
| | | | - Ferran Romero
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | - Martin Rulík
- Department of Ecology and Environmental Sciences, Palacky University in Olomouc, Olomouc, Czech Republic
| | - David Amouroux
- CNRS/ UNIV PAU & PAYS ADOUR, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Materiaux, UMR5254, MIRA, Pau, France.
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Liang P, Wu S, Zhang C, Xu J, Christie P, Zhang J, Cao Y. The role of antibiotics in mercury methylation in marine sediments. J Hazard Mater 2018; 360:1-5. [PMID: 30075378 DOI: 10.1016/j.jhazmat.2018.07.096] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 06/08/2023]
Abstract
The role of antibiotics commonly used in fish culture activities in methylmercury (MeHg) formation in mariculture sediments (MS) and in reference sediments (RS) was studied using simulation microcosms. MS and RS were split into three equal batches. Two batches were spiked with Hg(NO3)2 aqueous solution at levels of 2 and 8 mg kg-1 (dry weight basis) and the remainder served as a control batch. Tetracycline (TC) and oxytetracycline (OTC) (2.5 g and 10 g of each) were added to each treatment. Sediment THg concentration decreased during the culture period possibly due to complexation of Hg with the antibiotics resulting in the dissolution of Hg compounds from the sediment. More importantly, the MeHg concentration increased after 32 days together with a decrease in the concentrations of the antibiotics in the sediment. The complexation of TC or OTC with Hg resulted in the transport of electrons from TC or OTC to Hg2+ due to the high electronegativity of Hg2+. Subsequently, Hg2+ was reduced to Hg° which reacted with CH3+ derived from TC or OTC. The use of antibiotics may therefore promote the formation of MeHg in sediments.
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Affiliation(s)
- Peng Liang
- School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Lin'an, 311300, China; Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, Hangzhou 311300, China.
| | - Shengchun Wu
- School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Lin'an, 311300, China; Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, Hangzhou 311300, China.
| | - Chan Zhang
- College of Law and Political Science, Zhejiang Agriculture and Forestry University, Lin'an, China
| | - Jialin Xu
- School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Lin'an, 311300, China
| | - Peter Christie
- School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Lin'an, 311300, China; Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, Hangzhou 311300, China
| | - Jin Zhang
- School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Lin'an, 311300, China; Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, Hangzhou 311300, China
| | - Yucheng Cao
- School of Environmental and Resource Sciences, Zhejiang Agriculture and Forestry University, Lin'an, 311300, China; Zhejiang Province Key Laboratory of Soil Contamination and Bioremediation, Hangzhou 311300, China
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46
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Zhao T, Yu Z, Zhang J, Qu L, Li P. Low-thermal remediation of mercury-contaminated soil and cultivation of treated soil. Environ Sci Pollut Res Int 2018; 25:24135-24142. [PMID: 29948692 DOI: 10.1007/s11356-018-2387-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 05/22/2018] [Indexed: 06/08/2023]
Abstract
In this study, low-thermal technology was used to treat the mercury contaminated farmland soil from a chemical plant in Guizhou Province, China. A series of field planting experiments were also aimed at determining the content of total and methyl-Hg in crop plants after thermal treatment. The results showed that the mercury concentration in soils was reduced about 70% from 255.74 mg/kg to 80.63 mg/kg when treated at 350 °C for 30 min in engineering-scale experiments, and the treated soil retained most of its original soil. Organic-bound and residual mercury in treated soil were reduced by 64.1 and 56.4% by means of a sequential extraction procedure, respectively. The total and methyl-mercury concentrations in crops decreased significantly, and the degree of soil mercury accumulation to crop roots has been reduced significantly. The total Hg concentrations in potato and corn were lower than the mercury tolerance limits for food in China, and the Hg concentration of radish was close to the limit. The technology provides a more sustainable remediation method for treating mercury-contaminated farmland soil in future engineering applications.
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Affiliation(s)
- Ting Zhao
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Zhi Yu
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
- Research and Design Institute of Environmental Science of Guizhou Province, Guiyang, 550023, China
| | - Junfang Zhang
- Research and Design Institute of Environmental Science of Guizhou Province, Guiyang, 550023, China
| | - Liya Qu
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China.
- Research and Design Institute of Environmental Science of Guizhou Province, Guiyang, 550023, China.
| | - Ping Li
- Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China
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Tanner KC, Windham-Myers L, Marvin-DiPasquale M, Fleck JA, Tate KW, Linquist BA. Methylmercury Dynamics in Upper Sacramento Valley Rice Fields with Low Background Soil Mercury Levels. J Environ Qual 2018; 47:830-838. [PMID: 30025065 DOI: 10.2134/jeq2017.10.0390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Few studies have considered how methylmercury (MeHg, a toxic form of Hg produced in anaerobic soils) production in rice ( L.) fields can affect water quality, and little is known about MeHg dynamics in rice fields. Surface water MeHg and total Hg (THg) imports, exports, and storage were studied in two commercial rice fields in the Sacramento Valley, California, where soil THg was low (25 and 57 ng g). The median concentration of MeHg in drainage water exiting the fields was 0.17 ng g (range: <0.007-2.1 ng g). Compared with irrigation water, drainage water had similar MeHg concentrations, and lower THg concentrations during the growing season. Significantly elevated drainage water MeHg and THg concentrations were observed in the fallow season compared with the growing season. An analysis of surface water loads indicates that fields were net importers of both MeHg (76-110 ng m) and THg (1947-7224 ng m) during the growing season, and net exporters of MeHg (35-200 ng m) and THg (248-6496 ng m) during the fallow season. At harvest, 190 to 700 ng MeHg m and 1400 to 1700 ng THg m were removed from fields in rice grain. Rice straw, which contained 120 to 180 ng MeHg m and 7000-10,500 ng m THg was incorporated into the soil. These results indicate that efforts to reduce MeHg and THg exports in rice drainage water should focus on the fallow season. Substantial amounts of MeHg and THg were stored in plants, and these pools should be considered in future studies.
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Zhang X, Li Y, Feng G, Tai C, Yin Y, Cai Y, Liu J. Probing the DOM-mediated photodegradation of methylmercury by using organic ligands with different molecular structures as the DOM model. Water Res 2018; 138:264-271. [PMID: 29609155 DOI: 10.1016/j.watres.2018.03.055] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 06/08/2023]
Abstract
Photodegradation is the main depletion pathway for methylmercury (MeHg) in surface water. The formation of MeHg-dissolved organic matter (DOM) complexes has been found to be a key step in MeHg photodegradation. However, the major functional groups involved in the DOM-mediated process have yet to be clearly resolved. In this work, we systematically investigated the effects of DOM molecular structures on MeHg photodegradation by using a variety of organic ligands with different functional groups (e.g., thiosalicylate, thiophenol, and thioaniline). The results showed that thiol and phenyl groups may be the major functional groups governing DOM-mediated MeHg photodegradation, with photodegradation rates also dependent on the type (carboxyl, hydroxyl, and amino group) and position (ortho-, meta-, and para-) of other chemical substituents. The addition of "non-photochemically active" thiol ligands (e.g., mercaptoethanol and dithiothreitol) and high concentrations of Cl- can significantly inhibit the o-thiosalicylate-induced MeHg photodegradation, indicating that complexation of MeHg with these ligands is necessary for MeHg photodegradation. Sparging with O2 had a negligible effect on MeHg photodegradation, while sparging with N2 significantly enhanced MeHg photodegradation. This finding suggests that MeHg photodegradation may be a reductive process, which was further supported by identification of the degradation products of MeHg. A possible protonolysis mechanism of MeHg photodegradation in the presence of o-thiosalicylate was then proposed based on the findings of this study.
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Affiliation(s)
- Xiaoyan Zhang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Yanbin Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
| | - Gang Feng
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China
| | - Chao Tai
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo 454000, China
| | - Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Yong Cai
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Jingfu Liu
- 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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49
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Stoichev T, Tessier E, Almeida CMR, Basto MCP, Vasconcelos VM, Amouroux D. Flux model to estimate the transport of mercury species in a contaminated lagoon (Ria de Aveiro, Portugal). Environ Sci Pollut Res Int 2018; 25:17371-17382. [PMID: 29654462 DOI: 10.1007/s11356-018-1925-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/02/2018] [Indexed: 06/08/2023]
Abstract
The concentrations of dissolved and particulate inorganic mercury (IHg(II)) and methylmercury (MeHg) from the contaminated Laranjo Bay (main freshwater discharge from the Antuã River) were measured by species-specific isotope dilution during six sampling campaigns at high and at low tide. Different effective riverine concentrations were calculated, based on salinity profiles, for specific hydrological conditions. The export fluxes of total Hg and MeHg (324 and 1.24 mol year-1, respectively) from the bay to the rest of the Aveiro Lagoon are much higher than the input fluxes from the Hg source (3.9 and 0.05 mol year-1) and from the Antuã River (10.4 and 0.10 mol year-1). Resuspension of contaminated sediments from Laranjo Bay is crucial for the transport of both IHg(II) and MeHg. Methylation and/or selective enrichment into biogenic particles is responsible for the mobilization of MeHg. Sorption of dissolved IHg(II) onto suspended particles limits its export flux. This is one of the rarest examples where both speciation fluxes and partitioning of mercury are studied in a contaminated coastal environment. Despite the lower fraction of total MeHg (relative to total Hg), the contaminated lagoon may have an impact on coastal areas, particularly if change in the lagoon geometry occurs, due to sea level rise.
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Affiliation(s)
- Teodor Stoichev
- Interdisciplinary Center of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal.
| | - Emmanuel Tessier
- Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, CNRS/UNIV PAU & PAYS ADOUR, UMR5254, Mira, 64000, Pau, France
| | - Cristina Marisa R Almeida
- Interdisciplinary Center of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal
| | - Maria Clara P Basto
- Interdisciplinary Center of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal
- Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
| | - Vitor M Vasconcelos
- Interdisciplinary Center of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal
- Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
| | - David Amouroux
- Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, CNRS/UNIV PAU & PAYS ADOUR, UMR5254, Mira, 64000, Pau, France
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50
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Li D, Li Y, Wang X. Study on the simultaneous reduction of methylmercury by SnCl 2 when analyzing inorganic Hg in aqueous samples. J Environ Sci (China) 2018; 68:177-184. [PMID: 29908737 DOI: 10.1016/j.jes.2018.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/26/2018] [Accepted: 02/27/2018] [Indexed: 06/08/2023]
Abstract
Mercury (Hg) is among the most concerned contaminants in the world. It has three major chemical forms in the environment, including Hg0, Hg2+, and methylmercury (MeHg). Due to their differences in toxicity, mobility, and bioavailability, speciation analysis is critical for understanding Hg cycling and fate in the environment. SnCl2 reduction-atomic fluorescence spectrometry detection is the most commonly used method for analyzing inorganic Hg. However, it should be noted that MeHg may also be reduced by SnCl2, which would result in the overestimation of inorganic Hg. In this study, the reduction of MeHg by SnCl2 in both de-ionized (DI) water and four natural waters was investigated. The results showed that MeHg could be reduced by SnCl2 in DI water whereas this reaction was hard to occur in tested natural waters. By investigating the effects of water chemical characteristics (dissolved organic matter, pH and common anions and cations) on this reaction, SO42- was identified to be the dominant factor prohibiting SnCl2 induced MeHg reduction in natural waters. SO42- in natural waters was evidenced to be reduced to S2- by SnCl2 and the generated S2- can complex with MeHg to form MeHgS- which is hard to be reduced by SnCl2. Findings of this study indicate that the effect of MeHg reduction by SnCl2 on inorganic Hg analysis is negligible in natural waters; however, at simulated experimental systems without SO42-, SO42- should be added as protecting agents to prevent MeHg reduction when analyzing inorganic Hg if it would not cause any other unwanted effects.
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Affiliation(s)
- Dan Li
- Key Laboratory of Marine Chemistry Theory and Technology (Ocean University of China), Ministry of Education, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yanbin Li
- Key Laboratory of Marine Chemistry Theory and Technology (Ocean University of China), Ministry of Education, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
| | - Xiulin Wang
- Key Laboratory of Marine Chemistry Theory and Technology (Ocean University of China), Ministry of Education, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
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