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Li Z, Zhou C, Wang Y, He D, Liu M, Yin Y, Liu G, Wang X, Cai Y, Li Y. Total mercury, methylmercury, and their possible controlling factors in soils of typical coastal wetlands in China. JOURNAL OF HAZARDOUS MATERIALS 2024; 473:134711. [PMID: 38795491 DOI: 10.1016/j.jhazmat.2024.134711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/16/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
Coastal wetland soils play a critical role in the global mercury (Hg) cycle, serving as both an important repository for total mercury (THg) and a hotspot for methylmercury (MeHg) production. This study investigated Hg pollution in soils dominated by Phragmites australis (PA) and Spartina alterniflora (SA) across five representative China's coastal wetlands (Yellow River (YR), Linhong River (LHR), Yangtze River (CJR), Min River (MR), and Nanliu River (NLR)). The THg concentrations ranged from 16.7 to 446.0 (96.3 ± 59.3 ng g-1, dw), while MeHg concentrations varied from 0.01 to 0.81 (0.12 ± 0.12 ng g-1, dw). We further evaluated Hg risk in these wetlands using potential ecological risk index (Er) and geographical enrichment factor (Igeo). Most wetlands exhibited low to moderate ecological risk, except the PA habitat in the YR wetland, showing moderate to high risk. Soil organic matter significantly influenced THg and MeHg distribution, while MeHg% correlated well with soil salinity and pH. These findings highlight the importance of organic-rich coastal wetland soils in THg and MeHg accumulation, with the soil properties influencing net MeHg production. Furthermore, SA habitat generally exhibited higher MeHg%, suggesting its invasion elevates the ecological risk of MeHg in coastal wetlands. ENVIRONMENTAL IMPLICATION: Mercury (Hg), a global pollutant, poses great risks to wildlife and humans. Since industrialization, anthropogenic Hg release surpassed natural sources. Long-term exposure leads to biomagnification of Hg. This study assessed Hg and methylmercury pollution and risks in soils of five China's coastal wetlands dominated by Phragmites australis and Spartina alterniflora. Environmental factors (total carbon, total organic carbon, total nitrogen, salinity, pH) were analyzed to reveal key variables influencing Hg pollution and methylation. Essential for quantifying Hg pollution in coastal wetlands, the findings provide a scientific basis for effective wetland conservation policies and addressing environmental health in these regions.
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Affiliation(s)
- Zheng Li
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Chengzhen Zhou
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yingjun Wang
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Ding He
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Clear Water Bay, New Territories, Hong Kong 999077, China.
| | - Maodian Liu
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yongguang Yin
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Guangliang Liu
- Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Xuejun Wang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yong Cai
- Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, USA
| | - 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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Monteiro LC, Vieira LCG, Bernardi JVE, Recktenvald MCNDN, Nery AFDC, Fernandes IO, de Miranda VL, da Rocha DMS, de Almeida R, Bastos WR. Mercury distribution, bioaccumulation, and biomagnification in riparian ecosystems from a neotropical savanna floodplain, Araguaia River, central Brazil. ENVIRONMENTAL RESEARCH 2024; 252:118906. [PMID: 38609069 DOI: 10.1016/j.envres.2024.118906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/01/2024] [Accepted: 04/08/2024] [Indexed: 04/14/2024]
Abstract
Litterfall is the main source of dry deposition of mercury (Hg) into the soil in forest ecosystems. The accumulation of Hg in soil and litter suggests the possibility of transfer to terrestrial invertebrates through environmental exposure or ingestion of plant tissues. We quantified total mercury (THg) concentrations in two soil layers (organic: 0-0.2 m; mineral: 0.8-1 m), litter, fresh leaves, and terrestrial invertebrates of the Araguaia River floodplain, aiming to evaluate the THg distribution among terrestrial compartments, bioaccumulation in invertebrates, and the factors influencing THg concentrations in soil and invertebrates. The mean THg concentrations were significantly different between the compartments evaluated, being higher in organic soil compared to mineral soil, and higher in litter compared to mineral soil and fresh leaves. Soil organic matter content was positively related to THg concentration in this compartment. The order Araneae showed significantly higher Hg concentrations among the most abundant invertebrate taxa. The higher Hg concentrations in Araneae were positively influenced by the concentrations determined in litter and individuals of the order Hymenoptera, confirming the process of biomagnification in the terrestrial trophic chain. In contrast, the THg concentrations in Coleoptera, Orthoptera and Hymenoptera were not significantly related to the concentrations determined in the soil, litter and fresh leaves. Our results showed the importance of organic matter for the immobilization of THg in the soil and indicated the process of biomagnification in the terrestrial food web, providing insights for future studies on the environmental distribution of Hg in floodplains.
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Affiliation(s)
- Lucas Cabrera Monteiro
- Programa de Pós-Graduação em Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF, Brazil; Núcleo de Estudos e Pesquisas Ambientais e Limnológicas, Faculdade UnB Planaltina, Universidade de Brasília, Planaltina, DF, Brazil; Laboratório de Geoestatística e Geodésia, Faculdade UnB Planaltina, Universidade de Brasília, Planaltina, DF, Brazil.
| | - Ludgero Cardoso Galli Vieira
- Núcleo de Estudos e Pesquisas Ambientais e Limnológicas, Faculdade UnB Planaltina, Universidade de Brasília, Planaltina, DF, Brazil
| | - José Vicente Elias Bernardi
- Laboratório de Geoestatística e Geodésia, Faculdade UnB Planaltina, Universidade de Brasília, Planaltina, DF, Brazil
| | | | | | - Iara Oliveira Fernandes
- Programa de Pós-Graduação em Ciências Ambientais, Faculdade UnB Planaltina, Universidade de Brasília, Planaltina, DF, Brazil
| | - Vinicius Lima de Miranda
- Programa de Pós-Graduação em Zoologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF, Brazil
| | | | - Ronaldo de Almeida
- Laboratório de Biogeoquímica Ambiental, Universidade Federal de Rondônia, Porto Velho, RO, Brazil
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Chen L, Zhou J, Guo L, Bian X, Xu Z, Chen Q, Wen SH, Wang K, Liu YR. Global Distribution of Mercury in Foliage Predicted by Machine Learning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 38860911 DOI: 10.1021/acs.est.4c00636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Foliar assimilation of elemental mercury (Hg0) from the atmosphere plays a critical role in the global Hg biogeochemical cycle, leading to atmospheric Hg removal and soil Hg insertion. Recent studies have estimated global foliar Hg assimilation; however, large uncertainties remained due to coarse accounting of observed foliar Hg concentrations, posing a substantial challenge in constraining the global Hg budget. Here, we integrated a comprehensive observation database of foliar Hg concentrations and machine learning algorithms to predict the first spatial distribution of foliar Hg concentrations on a global scale, contributing to the first estimate of global Hg pools in foliage. The global average of foliar Hg concentrations was estimated to be 24.0 ng g-1 (7.5-56.5 ng g-1), and the global total in foliar Hg pools reached 4561.3 Mg (1455.2-9062.8 Mg). The spatial distribution showed the hotspots in tropical regions, including the Amazon, Central Africa, and Southeast Asia. A range of 2268.5-2727.0 Mg yr-1 was estimated for annual foliar Hg assimilation accounting for the perennial continuous assimilation by evergreen vegetation foliage. The first spatial maps of foliar Hg concentrations and Hg pools may aid in understanding the global biogeochemical cycling of Hg, especially in the context of climate change and global vegetation greening.
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Affiliation(s)
- Long Chen
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
- Key Laboratory of Spatial-temporal Big Data Analysis and Application of Natural Resources in Megacities, Ministry of Natural Resources, Shanghai 200241, China
| | - Jun Zhou
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Long Guo
- College of Resources and Environment and State Environmental Protection, Key Laboratory of Soil Health and Green Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Xinyu Bian
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
| | - Zeng Xu
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
| | - Qinzheng Chen
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
| | - Shu-Hai Wen
- College of Resources and Environment and State Environmental Protection, Key Laboratory of Soil Health and Green Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Kang Wang
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
| | - Yu-Rong Liu
- College of Resources and Environment and State Environmental Protection, Key Laboratory of Soil Health and Green Remediation, Huazhong Agricultural University, Wuhan 430070, China
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Li X, Hu D, Du J, He L. Understanding mercury accumulation in mosses of two subalpine forests in China. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134266. [PMID: 38626682 DOI: 10.1016/j.jhazmat.2024.134266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/10/2024] [Accepted: 04/08/2024] [Indexed: 04/18/2024]
Abstract
The role of forest ecosystems in the global mercury (Hg) biogeochemical cycle is widely recognized; however, using litterfall as a surrogate to assess the Hg sink function of forests encounters limitations. We investigated the accumulation characteristics and influencing factors of Hg in mosses from two remote subalpine forests in southwestern China. The results indicated that there was high Hg accumulation in subalpine forest mosses, with average concentrations of 82 ± 49 ng g-1 for total mercury (THg) and 1.3 ± 0.8 ng g-1 for methylmercury (MeHg). We demonstrated that the accumulation capacity of Hg in mosses was significantly dependent on species and substrates (micro-habitats), the mosses on tree trunks exhibited significantly elevated Hg accumulation levels (THg 132 ± 56 ng g-1, MeHg 1.6 ± 0.2 ng g-1) compared to mosses in other substrates. The surface morphologies and biochemical components of leaf (phyllidia), such as cation exchange capacity (CEC), pectin, uronic acid, and metallothionein, play a crucial role in the accumulation of Hg by mosses. These findings provide valuable insights into Hg accumulation in forest mosses. Suggesting that the contribution of mosses Hg accumulation should be considered when assessing atmospheric Hg sinks of forests.
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Affiliation(s)
- Xiaohui Li
- College of Life Science, Sichuan Normal University, No. 1819, Chenglong Road, Chengdu, Sichuan 610101, China.
| | - Dan Hu
- College of Life Science, Sichuan Normal University, No. 1819, Chenglong Road, Chengdu, Sichuan 610101, China.
| | - Jie Du
- Jiuzhaigou Scenic Area Administration, Zhangzha, Jiuzhaigou, Sichuan 623402, China.
| | - Lei He
- College of Life Science, Sichuan Normal University, No. 1819, Chenglong Road, Chengdu, Sichuan 610101, China.
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Navrátil T, Rohovec J, Nováková T, Roll M, Cudlín P, Oulehle F. Quarter century of mercury litterfall at a coniferous forest responding to climate change, Central Europe. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:34936-34952. [PMID: 38717703 DOI: 10.1007/s11356-024-33555-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/29/2024] [Indexed: 05/30/2024]
Abstract
This work evaluated the 25-year-long trends (1994-2018) in mercury (Hg) concentrations and fluxes in spruce litterfall at a forest research plot Načetín (NAC) recovering from acidic deposition in the Ore Mountains, Czech Republic. The mean litterfall Hg deposition averaged 51 ± 18 µg m-2 year-1, which has been the highest litterfall Hg deposition reported up to date on the European continent. In contrast, the wet deposition (2017-2019) was an order of magnitude lower averaging at 2.5 ± 1.5 µg m-2 year-1. All the spruce litterfall components bark, twigs, needles, cones, and a mixture of unidentified fragments had elevated mean Hg concentrations relative to background sites averaging 256 ± 77, 234 ± 62, 119 ± 23, 95 ± 14, and 44 ± 15 µg kg-1, respectively. Elevated litterfall Hg deposition and concentrations were attributed to the nearby local Hg emission source-coal-fired power plants. Temporally, the decrease of Czech Hg emissions since the 1990s was reflected by the decreasing trend of Hg concentrations in litterfall bark, cones, and twigs, while in needles and other material, Hg increased but insignificantly. Total litterfall ratios of Hg/C, Hg/N, and Hg/S were lower than those in soil O horizons averaging at 0.23 ± 0.04, 9.5 ± 2.0, and 170 ± 37 μg g-1, respectively. Since the beginning of monitoring, total litterfall Hg/C exhibited no trend, Hg/N decreased, and Hg/S increased. The litterfall biomass deposition averaging at 469 ± 176 g m-2 year-1 increased through time resulting in an increased Hg litterfall deposition at NAC by 1.1 µg m-2 year-1 despite the decreases in Czech Hg emissions. Peaks of annual litterfall Hg deposition up to 96 µg m-2 year-1 at NAC during the 25 years of monitoring resulted from weather extremes such as rime-snow accumulation, wind gusts, droughts, and insect infestation, which all significantly affected the annual biomass deposition. Based on our observations, further increases in biomass and litterfall Hg deposition rates can be expected due to the onset of bark beetle infestation and the increasing number of droughts caused by climate change.
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Affiliation(s)
- Tomáš Navrátil
- Institute of Geology, Czech Academy of Sciences, Rozvojová 269, 165 00, Prague 6, Czech Republic.
| | - Jan Rohovec
- Institute of Geology, Czech Academy of Sciences, Rozvojová 269, 165 00, Prague 6, Czech Republic
| | - Tereza Nováková
- Institute of Geology, Czech Academy of Sciences, Rozvojová 269, 165 00, Prague 6, Czech Republic
| | - Michal Roll
- Institute of Geology, Czech Academy of Sciences, Rozvojová 269, 165 00, Prague 6, Czech Republic
| | - Pavel Cudlín
- Global Change Research Institute, Czech Academy of Sciences, Poříčí 3B, 60 300, Brno, Czech Republic
| | - Filip Oulehle
- Global Change Research Institute, Czech Academy of Sciences, Poříčí 3B, 60 300, Brno, Czech Republic
- Czech Geological Survey, Klárov 3, 118 21, Prague 1, Czech Republic
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Yuan W, Wang X, Lin CJ, Zhang G, Wu F, Liu N, Jia L, Zhang H, Lu H, Dong J, Feng X. Fate and Transport of Mercury through Waterflows in a Tropical Rainforest. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4968-4978. [PMID: 38452105 DOI: 10.1021/acs.est.3c09265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Knowledge gaps of mercury (Hg) biogeochemical processes in the tropical rainforest limit our understanding of the global Hg mass budget. In this study, we applied Hg stable isotope tracing techniques to quantitatively understand the Hg fate and transport during the waterflows in a tropical rainforest including open-field precipitation, throughfall, and runoff. Hg concentrations in throughfall are 1.5-2 times of the levels in open-field rainfall. However, Hg deposition contributed by throughfall and open-field rainfall is comparable due to the water interception by vegetative biomasses. Runoff from the forest shows nearly one order of magnitude lower Hg concentration than those in throughfall. In contrast to the positive Δ199Hg and Δ200Hg signatures in open-field rainfall, throughfall water exhibits nearly zero signals of Δ199Hg and Δ200Hg, while runoff shows negative Δ199Hg and Δ200Hg signals. Using a binary mixing model, Hg in throughfall and runoff is primarily derived from atmospheric Hg0 inputs, with average contributions of 65 ± 18 and 91 ± 6%, respectively. The combination of flux and isotopic modeling suggests that two-thirds of atmospheric Hg2+ input is intercepted by vegetative biomass, with the remaining atmospheric Hg2+ input captured by the forest floor. Overall, these findings shed light on simulation of Hg cycle in tropical forests.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Ge Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China
| | - Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nantao Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Longyu Jia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Huazheng Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Jinlong Dong
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Tian Q, Zhang Z, Wang Z. Removal of potentially toxic elements from water with the moss-tufa micro-filtration system. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 272:116039. [PMID: 38310822 DOI: 10.1016/j.ecoenv.2024.116039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 01/21/2024] [Accepted: 01/27/2024] [Indexed: 02/06/2024]
Abstract
Mosses are an integral component in the tufa sedimentary landscape. In this study, we investigated the use of the porous moss-tufa structure as a filtration system for removing potentially toxic elements (PTEs) from water samples. Three species of mosses that commonly grow on tufa were selected, and the PTEs filtered by the moss-tufa system were identified by inductively coupled plasma mass spectrometry. The bioconcentration factor (BCF) of mosses was calculated to compare the enrichment effects of different mosses on PTEs. Likewise, the level of PTEs flowing through the moss-tufa system was measured, and the water quality removal rate (C) was calculated accordingly. The results revealed that the moss-tufa system was mainly composed of Fissidens grandifrons Brid., Hydrogonium dixonianum P. C. Chen, and Cratoneuron filicinum (Hedw.) Spruce var. filicinum. Among these, Fissidens grandifrons Brid. reported the highest retention capacity for PTEs. Collectively, the moss-tufa filtration system displayed a strong retention capacity and removal rate of Mn, Pb, and Ni from the water sample. The removal of PTEs by the moss-tufa system was mainly based on the enrichment of mosses and the adsorption-retention ability of tufa. In conclusion, the moss-tufa micro-filtration system displayed the effective removal of PTEs from water samples and could be applied to control the levels of toxic elements in karst water bodies.
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Affiliation(s)
- Qingrong Tian
- Key Laboratory for Information System of Mountainous Area and Protection of Ecological Environment of Guizhou Province, Guizhou Normal University, Guiyang 550001, China
| | - Zhaohui Zhang
- Key Laboratory for Information System of Mountainous Area and Protection of Ecological Environment of Guizhou Province, Guizhou Normal University, Guiyang 550001, China
| | - Zhihui Wang
- School of Life Sciences, Guizhou Normal University, Guiyang 55001, China
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Fernandes IO, Monteiro LC, de Miranda VL, Rodrigues YOS, de Freitas Muniz DH, de Castro Paes É, Bernardi JVE. Mercury distribution in organisms, litter, and soils of the Middle Araguaia floodplain in Brazil. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:20925-20940. [PMID: 38379047 DOI: 10.1007/s11356-024-32317-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 01/29/2024] [Indexed: 02/22/2024]
Abstract
Mercury (Hg) is a chemical element that, depending on its concentration, may become toxic to living organisms due to the ability of Hg to bioaccumulate in food chains. In this study, we collected samples of soil, litter, and organisms in the Middle Araguaia floodplain, Brazil. Total mercury (THg) concentrations in litter were significantly higher (p < 0.0001) than that in soil, ranging from 10.68 ± 0.55 to 48.94 ± 0.13 and 20.80 ± 1.07 to 55 .19 ± 1.59 ng g-1, respectively. Total mercury concentration levels in soil showed a linear, inversely proportional relationship with soil organic matter (SOM) contents and soil pH, consistent with the geochemical behavior of chemical elements in flooded environments. Ten orders of organisms were identified, and the average THg concentrations determined in their bodies were up to 20 times higher than those in soil and litter. We found a significant linear relationship between the levels of THg in litter and those found in soil organisms, thereby allowing the prediction of THg concentration levels in soil organisms through the analysis of litter at the sample units. The different dynamics and feeding habits of soil organisms and the concentration of THg in these organisms may be influenced by the river's course. This study provides evidence of the bioaccumulation of THg in soil organisms in the floodplain of the Middle Araguaia River, an important river basin in the Brazilian savanna.
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Affiliation(s)
- Iara Oliveira Fernandes
- Graduate Program in Environmental Sciences, Faculty UnB Planaltina, University of Brasília, Planaltina, Distrito Federal, 73345-010, Brazil.
| | - Lucas Cabrera Monteiro
- Graduate Program in Ecology, Institute of Biological Sciences, University of Brasília, Brasília, Distrito Federal, 70910-900, Brazil
| | - Vinícius Lima de Miranda
- Graduate Program in Zoology, Institute of Biological Sciences, University of Brasília, Brasília, Distrito Federal, 70910-900, Brazil
| | - Ygor Oliveira Sarmento Rodrigues
- Graduate Program in Environmental Sciences, Faculty UnB Planaltina, University of Brasília, Planaltina, Distrito Federal, 73345-010, Brazil
| | - Daphne Heloisa de Freitas Muniz
- Graduate Program in Environmental Sciences, Faculty UnB Planaltina, University of Brasília, Planaltina, Distrito Federal, 73345-010, Brazil
| | - Ésio de Castro Paes
- Graduate Program in Soils and Plant Nutrition, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | - José Vicente Elias Bernardi
- Graduate Program in Environmental Sciences, Faculty UnB Planaltina, University of Brasília, Planaltina, Distrito Federal, 73345-010, Brazil
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Li S, Li Z, Wu M, Zhou Y, Tang W, Zhong H. Mercury transformations in algae, plants, and animals: The occurrence, mechanisms, and gaps. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 911:168690. [PMID: 38000748 DOI: 10.1016/j.scitotenv.2023.168690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023]
Abstract
Mercury (Hg) is a global pollutant showing potent toxicity to living organisms. The transformations of Hg are critical to global Hg cycling and Hg exposure risks, considering Hg mobilities and toxicities vary depending on Hg speciation. Though currently well understood in ambient environments, Hg transformations are inadequately explored in non-microbial organisms. The primary drivers of in vivo Hg transformations are far from clear, and the impacts of these processes on global Hg cycling and Hg associated health risks are not well understood. This hinders a comprehensive understanding of global Hg cycling and the effective mitigation of Hg exposure risks. Here, we focused on Hg transformations in non-microbial organisms, particularly algae, plants, and animals. The process of Hg oxidation/reduction and methylation/demethylation in organisms were reviewed since these processes are the key transformations between the dominant Hg species, i.e., elemental Hg (Hg0), divalent inorganic Hg (IHgII), and methylmercury (MeHg). By summarizing the current knowledge of Hg transformations in organisms, we proposed the potential yet overlooked drivers of these processes, along with potential challenges that hinder a full understanding of in vivo Hg transformations. Knowledge summarized in this review would help achieve a comprehensive understanding of the fate and toxicity of Hg in organisms, providing a basis for predicting Hg cycles and mitigating human exposure.
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Affiliation(s)
- Shouying Li
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Zhuoran Li
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Mengjie Wu
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Yang Zhou
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Wenli Tang
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China.
| | - Huan Zhong
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China.
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Ali SW, Božič D, Vijayakumaran Nair S, Živković I, Gačnik J, Andron TD, Jagodic Hudobivnik M, Kocman D, Horvat M. Optimization of a pre-concentration method for the analysis of mercury isotopes in low-concentration foliar samples. Anal Bioanal Chem 2024; 416:1239-1248. [PMID: 38193932 PMCID: PMC10850019 DOI: 10.1007/s00216-023-05116-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 01/10/2024]
Abstract
Hg isotope analysis in samples from background regions is constrained by the presence of low Hg concentration and therefore requires a pre-concentration method. Existing Hg pre-concentration methods are constrained by long sample processing time and limited sample loading capacity. Using foliar samples as a test case, an optimized Hg pre-concentration method is presented that involves the microwave-assisted digestion of samples for Hg isotope analysis with the addition of a pre-digestion step. Microwave-digested foliar samples and CRMs were transferred to an impinger, reduced with SnCl2, and collected in a 2.25 mL concentrated inverse aqua regia (3:1 HNO3:HCl, v/v). This resulted in an optimal acid concentration in the solution ideal for analysis on MC-ICP-MS. The time for purging with Hg-free N2 was optimized to 30 min and the efficiency of the pre-concentration method was tested using a combination of approaches. Tests performed on pure reagents and matrix of foliar samples spiked with 197Hg radiotracer showed recoveries averaging 99 ± 1.7% and 100 ± 3.0%, respectively. Mercury at concentrations as low as 1.83 ng g-1 was pre-concentrated by digesting aliquots of foliage samples in individual digestion vessels. Recoveries following their pre-concentration averaged 99 ± 6.0%, whereas recoveries of 95 ± 4.7% and 95 ± 2.5% were achieved for NIST SRM 1575a (pine needle) and reagents spiked with NIST SRM 3133, respectively. Analysis using multicollector-ICP-MS showed low fractionation of δ202Hg during sample pre-concentration with no significant mass-independent fractionation. The proposed method is a relatively simple and robust way to prepare Hg samples for Hg isotopic analysis and is suitable even for complex biological matrices.
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Affiliation(s)
- Saeed Waqar Ali
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Dominik Božič
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Sreekanth Vijayakumaran Nair
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Igor Živković
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Jan Gačnik
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Teodor-Daniel Andron
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | | | - David Kocman
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
| | - Milena Horvat
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia.
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia.
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11
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Wang D, Li Z, Wang Q. Estimation of mercury uptake and distinction of corn cultivation in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167508. [PMID: 37788774 DOI: 10.1016/j.scitotenv.2023.167508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/15/2023] [Accepted: 09/29/2023] [Indexed: 10/05/2023]
Abstract
Corn cultivation potentially plays a vital role in the global mercury (Hg) biogeochemical cycle. Nevertheless, there have been limited studies quantifying the Hg mass flow during corn cultivation. This study focuses on Hg uptake by corn plants in China, integrating data from both sample collection and prior studies, resulting in 400 datasets. The findings reveal that the Hg in corn plants is mainly incorporated in leaves (45.5 %-47.5 %) and husks (14.5 %-15.7 %). Despite a decrease in total gaseous Hg (TGM) concentrations in the atmosphere over time, annual Hg uptake by corn cultivation in China has risen from 72.0 (ranging from 47.6 to 96.3) tons (2009-2014) to 84.3 (ranging from 51.9 to 109.6) tons (2015-2020) due to the increasing in corn kernel production. Spatial analysis demonstrates regional disparities in Hg uptake, primarily influenced by corn kernel production, TGM levels, and soil Hg content. Furthermore, temporal analysis reveals a shift in the fate of Hg in corn plants, which can be attributed to variations in corn straw treatment policy or methods. From 2009 to 2014, a substantial amount of absorbed Hg by corn plants was re-released into the atmosphere (48.9 %) due to corn residues burning, whereas, between 2015 and 2020, a greater proportion of Hg ended up accumulating in the soil (51.1 %) after the imposition of the straw burning ban in China. Prior to the ban (2009-2014), corn cultivation contributed approximately 7.7 tons of Hg input to soil annually, with a range from 1.7 to 13.5. However, following the ban (2015-2020), Hg input into the soil increased by approximately 4.5 times, reaching 34.5 (ranging from 17.5 to 52.6) tons per year. These findings emphasize the significant risks associated with soil Hg pollution caused by corn cultivation due to the straw burning ban.
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Affiliation(s)
- Dan Wang
- Department of Resources and Environment, Zunyi Normal College, Zunyi 563006, PR China
| | - Zhonggen Li
- Department of Resources and Environment, Zunyi Normal College, Zunyi 563006, PR China
| | - Qingfeng Wang
- Department of Resources and Environment, Zunyi Normal College, Zunyi 563006, PR China.
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12
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Sa R, Wang Z, Xu Z, Zhao Q, Zhang Q, Zhang X. Distribution characteristics of mercury concentration and estimation of mercury pools in different age groups of Larix gmelinii forests of Daxing'an Mountain. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 338:122653. [PMID: 37778492 DOI: 10.1016/j.envpol.2023.122653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/03/2023]
Abstract
Forests are important sinks of atmospheric mercury. Quantifying mercury pools in forest ecosystem tissues are essential for understanding the global mercury cycle. To reveal the characteristics of Hg concentration and Hg pool distribution in natural forests at different ages, samples from the vegetation layer, organic horizons, coarse wood debris, and mineral soil layers were collected in young forest, middle forest, near-mature forest, and mature forest of Larix gmelinii forests at the Daxing'an Mountain. The results showed that there were differences in the absorption and accumulation of Hg by different tree species and tissues. In Larix gmelinii, the concentration of Hg followed the order of bark > branch > leaf > root > core, whereas in Betula platyphylla, the order was bark > leaf > branch > root > core. The mercury concentration in the organic horizons increased gradually with the decomposition process. There were no obvious regular patterns in the mercury concentrations of each tissue in different age groups Larix gmelinii forests. Furthermore, total biomass mercury pools (overstory, shrub layer, herb layer, moss layer, and coarse woody debris (CWD)) in the young, middle, near-mature, and mature forests of Larix gmelinii forests at Daxing'an Mountain were estimated to be 99.0 μg m-2,207 μg m-2,207 μg m-2 and 194 μg m-2, respectively. On ecosystem scale, total mercury pools were 16.9 mg m-2 (young), 27.5 mg m-2 (middle), 17.0 mg m-2 (near-mature), and 11.8 mg m-2(mature). The mineral soil mercury pool accounts for 94.0%-98.1% of the total ecosystem mercury pool, and its mercury pool proportion gradually decreased with the increase in forest age. These obtained results are quite valuable for further assessing the role of forest ecosystems in the atmospheric mercury cycle and estimating potential mercury emissions from biomass burning during forest wildfires.
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Affiliation(s)
- Rula Sa
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Inner Mongolia Power (Group) Co., Ltd., Inner Mongolia Power Research Institute Branch, Hohhot, Inner Mongolia Autonomous Region, 010020, China
| | - Zhangwei Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Zehua Xu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qingpeng Zhao
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qiuliang Zhang
- Inner Mongolia Agricultural University, Hohhot, 010019, China; National Field Scientific Observation and Research Station of Greater Khingan Forest Ecosystem, Inner Mongolia, Genhe, 022350, China
| | - Xiaoshan Zhang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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13
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Chu Z, Zhou Y, Liu M, Lin H, Cheng M, Xie H, Yuan L, Zhang Z, Zhang Q, Li C, Chen Y, Guo Y, Chen L, Wang X. Large-Scale Observations Support Aboveground Vegetation as an Important Biological Mercury Sink in the Tibetan Plateau. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17278-17290. [PMID: 37919873 DOI: 10.1021/acs.est.3c05164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Mercury, a pervasive global pollutant, primarily enters the atmosphere through human activities and legacy emissions from the land and oceans. A significant portion of this mercury subsequently settles on land through vegetation uptake. Characterizing mercury storage and distribution within vegetation is essential for comprehending regional and global mercury cycles. We conducted an unprecedented large-scale aboveground vegetation mercury survey across the expansive Tibetan Plateau. We find that mosses (31.1 ± 0.5 ng/g) and cushion plants (15.2 ± 0.7 ng/g) outstood high mercury concentrations. Despite exceptionally low anthropogenic mercury emissions, mercury concentrations of all biomes exceeded at least one-third of their respective global averages. While acknowledging the role of plant physiological factors, statistical models emphasize the predominant impact of atmospheric mercury on driving variations in mercury concentrations. Our estimations indicate that aboveground vegetation on the plateau accumulates 32-12+21 Mg (interquartile range) mercury. Forests occupy the highest biomass and store 82% of mercury, while mosses, representing only 3% of the biomass, disproportionally contribute 13% to mercury storage and account for 43% (2.5-1.4+3.0 Mg/year) of annual mercury assimilation by vegetation. Additionally, our study underscores that extrapolating aboveground vegetation mercury storage from lower-altitude regions to the Tibetan Plateau can lead to substantial overestimation, inspiring further exploration in alpine ecosystems worldwide.
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Affiliation(s)
- Zhaohan Chu
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yunzhuo Zhou
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Maodian Liu
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
- School of the Environment, Yale University, New Haven, Connecticut 06511, United States
| | - Huiming Lin
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Menghan Cheng
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Han Xie
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Liuliang Yuan
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Zhihao Zhang
- Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
| | - Qianru Zhang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Chengcheng Li
- Modern Chinese Literature, Department of Chinese Language and Literature, Peking University, Beijing 100871, China
| | - Yuang Chen
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yanpei Guo
- Institute of Ecology, Key Laboratory for Earth Surface Processes and College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Long Chen
- Key Laboratory of Geographic Information Science, Ministry of Education, East China Normal University, Shanghai 200241, China
| | - Xuejun Wang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
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14
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Du H, Wang X, Yuan W, Wu F, Jia L, Liu N, Lin CJ, Gan J, Zeng F, Wang K, Feng X. Elevated Mercury Deposition, Accumulation, and Migration in a Karst Forest. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17490-17500. [PMID: 37908057 DOI: 10.1021/acs.est.3c05409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The karst forest is one of the extremely sensitive and fragile ecosystems in southwest China, where the biogeochemical cycling of mercury (Hg) is largely unknown. In this study, we investigated the litterfall deposition, accumulation, and soil migration of Hg in an evergreen-deciduous broadleaf karst forest using high-resolution sampling and stable isotope techniques. Results show that elevated litterfall Hg concentrations and fluxes in spring are due to the longer lifespan of evergreen tree foliage exposed to atmospheric Hg0. The hillslope has 1-2 times higher litterfall Hg concentration compared to the low-lying land due to the elevated atmospheric Hg levels induced by topographical and physiological factors. The Hg isotopic model suggests that litterfall Hg depositions account for ∼80% of the Hg source contribution in surface soil. The spatial trend of litterfall Hg deposition cannot solely explain the trend of Hg accumulation in the surface soil. Indeed, soil erosion enhances Hg accumulation in soil of low-lying land, with soil Hg concentration up to 5-times greater than the concentration on the hillslope. The high level of soil Hg migration in the karst forest poses significant ecological risks to groundwater and downstream aquatic ecosystems.
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Affiliation(s)
- Hu Du
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Longyu Jia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Nantao Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Jiang Gan
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Fuping Zeng
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Kelin Wang
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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15
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Wu F, Yang L, Wang X, Yuan W, Lin CJ, Feng X. Mercury Accumulation and Sequestration in a Deglaciated Forest Chronosequence: Insights from Particulate and Mineral-Associated Forms of Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16512-16521. [PMID: 37857302 DOI: 10.1021/acs.est.3c03107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Understanding mercury (Hg) complexation with soil organic matter is important in assessing atmospheric Hg accumulation and sequestration processes in forest ecosystems. Separating soil organic matter into particulate organic matter (POM) and mineral-associated organic matter (MAOM) can help in the understanding of Hg dynamics and cycling due to their very different chemical constituents and associated formation and functioning mechanisms. The concentration of Hg, carbon, and nitrogen contents and isotopic signatures of POM and MAOM in a deglaciated forest chronosequence were determined to construct the processes of Hg accumulation and sequestration. The results show that Hg in POM and MAOM are mainly derived from atmospheric Hg0 deposition. Hg concentration in MAOM is up to 76% higher than that in POM of broadleaf forests and up to 60% higher than that in POM of coniferous forests. Hg accumulation and sequestration in organic soil vary with the vegetation succession. Variations of δ202Hg and Δ199Hg are controlled by source mixing in the broadleaf forest and by Hg sequestration processes in the coniferous forest. Accumulation of atmospheric Hg and subsequent microbial reduction enrich heavier Hg isotopes in MAOM compared to POM due to the specific chemical constituents and nutritional role of MAOM.
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Affiliation(s)
- Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luhan Yang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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16
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Chen C, Huang JH, Li K, Osterwalder S, Yang C, Waldner P, Zhang H, Fu X, Feng X. Isotopic Characterization of Mercury Atmosphere-Foliage and Atmosphere-Soil Exchange in a Swiss Subalpine Coniferous Forest. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15892-15903. [PMID: 37788478 DOI: 10.1021/acs.est.3c03576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
To understand the role of vegetation and soil in regulating atmospheric Hg0, exchange fluxes and isotope signatures of Hg were characterized using a dynamic flux bag/chamber at the atmosphere-foliage/soil interfaces at the Davos-Seehornwald forest, Switzerland. The foliage was a net Hg0 sink and took up preferentially the light Hg isotopes, consequently resulting in large shifts (-3.27‰) in δ202Hg values. The soil served mostly as net sources of atmospheric Hg0 with higher Hg0 emission from the moss-covered soils than from bare soils. The negative shift of δ202Hg and Δ199Hg values of the efflux air relative to ambient air and the Δ199Hg/Δ201Hg ratio among ambient air, efflux air, and soil pore gas highlight that Hg0 re-emission was strongly constrained by soil pore gas evasion together with microbial reduction. The isotopic mass balance model indicates 8.4 times higher Hg0 emission caused by pore gas evasion than surface soil photoreduction. Deposition of atmospheric Hg0 to soil was noticeably 3.2 times higher than that to foliage, reflecting the high significance of the soil to influence atmospheric Hg0 isotope signatures. This study improves our understanding of Hg atmosphere-foliage/soil exchange in subalpine coniferous forests, which is indispensable in the model assessment of forest Hg biogeochemical cycling.
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Affiliation(s)
- Chaoyue Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Jen-How Huang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Environmental Geosciences, University of Basel, 4056 Basel, Switzerland
| | - Kai Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Stefan Osterwalder
- Environmental Geosciences, University of Basel, 4056 Basel, Switzerland
- Institute of Agricultural Sciences, ETH Zurich, 8092 Zurich, Switzerland
| | - Chenmeng Yang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Peter Waldner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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17
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Hu J, Zheng L, Liu S, Chen Y, Li C, Ni J, Chen Y, An S. Quantifying the impacts of coal mining activities on topsoil using Hg stable isotope: A case study of Guqiao mining area, Huainan City. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 335:122378. [PMID: 37586683 DOI: 10.1016/j.envpol.2023.122378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/30/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
The Hg released from coal mining activities can endanger soil ecosystems and pose a risk to human health. Understanding the accumulation characteristics of mercury (Hg) in coal mining soil is important for effectively controlling Hg emissions and developing measures for the prevention and control of Hg contamination. To identify the potential sources of Hg in soils, the Hg concentration and isotopic composition characteristics of raw coal and different topsoil types from the areas surrounding a coal mine were determined in this study. The results showed that Hg in coal mainly exists mainly in the form of inorganic Hg, and Hg has experienced Hg2+ photoreduction prior to incorporating into coal. In addition, the composition of Hg isotopes differed significantly among different topsoil types, and the δ202Hg value of the farmland soil exhibited large negative excursions compared to the coal mining soil. The ternary mixed model further revealed the presence of substantial differences in potential Hg sources among the two regions, with the coal mining soil being greatly disturbed by anthropogenic activity, and the relative contributions of Hg from raw coal, coal gangue, and background soil to coal mining soil being 33.42%, 34.4%, and 32.19%, respectively. However, Hg from raw coal, coal gangue and background soil contributed 17.04%, 21.46%, and 61.51% of the Hg in the farmland soil, indicating that the accumulation of Hg in farmland soil was derived primarily from the background soil. Our study demonstrated that secondary pollution in soil caused by immense accumulation of solid waste (gangue) by mining activities offers a significant challenge to ecological security. These findings provide new insights into controlling soil Hg in mining areas and further highlight the urgency of strict protective measures for contaminated sites.
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Affiliation(s)
- Jie Hu
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Liugen Zheng
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China.
| | - Sikui Liu
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Yeyu Chen
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Chang Li
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Jincheng Ni
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Yongchun Chen
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan, 232001, Anhui, China
| | - Shikai An
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan, 232001, Anhui, China
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18
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Chen P, Wang X, Yuan W, Wang D. Typical heavy metals accumulation, transport and allocation in a deglaciated forest chronosequence, Qinghai-Tibet Plateau. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132162. [PMID: 37517237 DOI: 10.1016/j.jhazmat.2023.132162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/25/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Understanding heavy metals (HMs) accumulation and transportation is the foundation to assess the ecological risks caused by the pollution of HMs in terrestrial ecosystems. There are large knowledge gaps regarding impacts of vegetation succession on shaping the HMs accumulation, transportation and allocation in the remote alpine regions. Herein, we comprehensively investigated the distribution and source contribution of mercury (Hg), cadmium (Cd) and chromium (Cr) along with vegetation succession in a deglaciated forest chronosequence of Qinghai-Tibet Plateau. Results showed that Hg and Cd were highly enriched in organic soils, while Cr concentrations and pool sizes decreased significantly with the vegetation succession. Atmospheric Hg deposition contributed to the dominant Hg sources in topsoil (74 - 87%), whereas moraine weathering was the main source of Cr (73 - 76%). Both moraine (18 - 48%) and atmospheric deposition inputs (52 - 82%) affected Cd accumulation in topsoil. Over the last century, the accumulation rate of Hg and Cd showed the distinctly decreasing trends due to the vegetation leading to the elevated atmospheric depositions at the earlier deglacial sites. The negative accumulation rate of Cr along with the vegetation succession reflected the formation of organic soil diluting the geogenic inputs of Cr.
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Affiliation(s)
- Peijia Chen
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China.
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19
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Richter L, Amouroux D, Tessier E, Fostier AH. Impact of forest fire on the mercury stable isotope composition in litter and soil in the Amazon. CHEMOSPHERE 2023; 339:139779. [PMID: 37567261 DOI: 10.1016/j.chemosphere.2023.139779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 07/12/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023]
Abstract
Mercury (Hg) emissions from forest fires, especially tropical forests such as the Amazonian forest, were shown to contribute significantly to the atmospheric mercury budget, but new methods are still necessary to improve the traceability and to reduce the great uncertainties related to this emission source. Recent studies have shown that the combustion process can result in Hg stable isotope fractionation that allows tracking coal combustion Hg emissions, as influenced by different factors such as combustion temperature. The main goal of the present study was, therefore, to investigate for the first time the potential of Hg stable isotopes to trace forest fire Hg emissions and pathways. More specifically, small-scale and a large scale prescribed forest fire experiments were conducted in the Brazilian Amazonian forest to study the impact of fire severity on Hg isotopic composition of litter, soil, and ash samples and associated Hg isotope fractionation pathways. In the small-scale experiment, no difference was found in the mercury isotopic composition of the samples collected before and after burning. In contrast, the larger-scale experiment resulted in significant mass dependent fractionation (MDF δ202Hg) in soils and ash suggesting that higher combustion temperature influence Hg isotopic fractionation with the emission of lighter Hg isotopes to the atmosphere and enrichment with heavier Hg in ashes. As for coal combustion, mass independent fractionation was not observed. To our knowledge, these results are the first to highlight the potential of forest fires to cause Hg isotopic fractionation, depending on the fire severity. The results also allowed to establish an isotopic fingerprint for tropical forest fire Hg emissions that corresponds to a mixture of litter and soil Hg isotopic composition (resulting atmospheric δ202Hg, Δ200Hg and Δ199Hg were -1.79 ± 0.24‰, -0.05 ± 0.04‰ and -0.45 ± 0.12‰, respectively).
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Affiliation(s)
- Larissa Richter
- Institute of Chemistry, University of Campinas (UNICAMP), 13083-970, Campinas, São Paulo, Brazil
| | - David Amouroux
- Université de Pau et des Pays de L'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour L'Environnement et Les Matériaux, Pau, France.
| | - Emmanuel Tessier
- Université de Pau et des Pays de L'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour L'Environnement et Les Matériaux, Pau, France
| | - Anne Hélène Fostier
- Institute of Chemistry, University of Campinas (UNICAMP), 13083-970, Campinas, São Paulo, Brazil.
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Liu YR, Guo L, Yang Z, Xu Z, Zhao J, Wen SH, Delgado-Baquerizo M, Chen L. Multidimensional Drivers of Mercury Distribution in Global Surface Soils: Insights from a Global Standardized Field Survey. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:12442-12452. [PMID: 37506289 DOI: 10.1021/acs.est.3c04313] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Soil stores a large amount of mercury (Hg) that has adverse effects on human health and ecosystem safety. Significant uncertainties still exist in revealing environmental drivers of soil Hg accumulation and predicting global Hg distribution owing to the lack of field data from global standardized analyses. Here, we conducted a global standardized field survey and explored a holistic understanding of the multidimensional environmental drivers of Hg accumulation in global surface soils. Hg content in surface soils from our survey ranges from 3.8 to 618.2 μg kg-1 with an average of 74.0 μg kg-1 across the globe. Atmospheric Hg deposition, particularly vegetation-induced elemental Hg0 deposition, is the major source of surface soil Hg. Soil organic carbon serves as the major substrate for sequestering Hg in surface soils and is significantly influenced by agricultural management, litterfall, and elevation. For human activities, changing land-use could be a more important contributor than direct anthropogenic emissions. Our prediction of a new global Hg distribution highlights the hot spots (high Hg content) in East Asia, the Northern Hemispheric temperate/boreal regions, and tropical areas, while the cold spots (low Hg content) are in arid regions. The holistic understanding of multidimensional environmental drivers helps to predict the Hg distribution in global surface soils under a changing global environment.
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Affiliation(s)
- Yu-Rong Liu
- College of Resources and Environment and State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Long Guo
- College of Resources and Environment and State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Ziming Yang
- Department of Chemistry, Oakland University, Rochester, Michigan 48309, United States
| | - Zeng Xu
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Jiating Zhao
- Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Shu-Hai Wen
- College of Resources and Environment and State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Manuel Delgado-Baquerizo
- Laboratorio de Biodiversidad y Funcionamiento Ecosistemico, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Sevilla 41012, Spain
- Unidad Asociada CSIC-UPO (BioFun), Universidad Pablo de Olavide, Sevilla 41013, Spain
| | - Long Chen
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, Shanghai 200241, China
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21
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Yuan W, Wang X, Lin CJ, Song Q, Zhang H, Wu F, Liu N, Lu H, Feng X. Deposition and Re-Emission of Atmospheric Elemental Mercury over the Tropical Forest Floor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:10686-10695. [PMID: 37437160 DOI: 10.1021/acs.est.3c01222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Significant knowledge gaps exist regarding the emission of elemental mercury (Hg0) from the tropical forest floor, which limit our understanding of the Hg mass budget in forest ecosystems. In this study, biogeochemical processes of Hg0 deposition to and evasion from soil in a Chinese tropical rainforest were investigated using Hg stable isotopic techniques. Our results showed a mean air-soil flux as deposition of -4.5 ± 2.1 ng m-2 h-1 in the dry season and as emission of +7.4 ± 1.2 ng m-2 h-1 in the rainy season. Hg re-emission, i.e., soil legacy Hg evasion, induces negative transitions of Δ199Hg and δ202Hg in the evaded Hg0 vapor, while direct atmospheric Hg0 deposition does not exhibit isotopic fractionation. Using an isotopic mass balance model, direct atmospheric Hg0 deposition to soil was estimated to be 48.6 ± 13.0 μg m-2 year-1. Soil Hg0 re-emission was estimated to be 69.5 ± 10.6 μg m-2 year-1, of which 63.0 ± 9.3 μg m-2 year-1 is from surface soil evasion and 6.5 ± 5.0 μg m-2 year-1 from soil pore gas diffusion. Combined with litterfall Hg deposition (∼34 μg m-2 year-1), we estimated a ∼12.6 μg m-2 year-1 net Hg0 sink in the tropical forest. The fast nutrient cycles in the tropical rainforests lead to a strong Hg0 re-emission and therefore a relatively weaker atmospheric Hg0 sink.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Qinghai Song
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nantao Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Huazheng Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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22
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Méndez-López M, Eimil-Fraga C, Alonso-Vega F, Rodríguez-Soalleiro R, Álvarez-Rodríguez E, Arias-Estévez M, Nóvoa-Muñoz JC. Variation of Hg concentration and accumulation in the soil of maritime pine plantations along a coast-inland transect in SW Europe. ENVIRONMENTAL RESEARCH 2023; 231:116155. [PMID: 37196692 DOI: 10.1016/j.envres.2023.116155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 04/13/2023] [Accepted: 05/13/2023] [Indexed: 05/19/2023]
Abstract
Climatic conditions have been shown as a major driver of the fate of Hg in forest ecosystems at a global scale, but less is known about climatic effects at shorter scales. This study assesses whether the concentration and pools of Hg in soils collected from seventeen Pinus pinaster stands describing a coastal-inland transect in SW Europe vary along a regional climatic gradient. In each stand, samples of the organic subhorizons (OL, OF + OH) and the mineral soil (up to 40 cm) were collected and some general physico-chemical properties and total Hg (THg) were analyzed. Total Hg was significantly higher in the OF + OH than in the OL subhorizons (98 and 38 μg kg-1, respectively), favored by a greater organic matter humification in the former. In the mineral soil, mean THg values decreased with depth, ranging from 96 μg kg-1 in the 0-5 cm layers to 54 μg kg-1 in the deepest layers (30-40 cm), respectively. The average Hg pool (PHg) was 0.30 mg m-2 in the organic horizons (92% accumulated in the OF + OH subhorizons), and 27.4 mg m-2 in the mineral soil. Changes in climatic factors, mainly precipitation, along the coast-inland transect resulted in a remarkable variation of THg in the OL subhorizons, consistent with their role as the first receiver of atmospheric Hg inputs. The high precipitation rate and the occurrence of fogs in coastal areas characterized by the oceanic influence would explain the higher THg found in the uppermost soil layers of pine stands located close to the coastline. The regional climate is key to the fate of mercury in forest ecosystems by influencing the plant growth and subsequent atmospheric Hg uptake, the atmospheric Hg transference to the soil surface (wet and dry deposition and litterfall) and the dynamics that determine net Hg accumulation in the forest floor.
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Affiliation(s)
- Melissa Méndez-López
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain.
| | - Cristina Eimil-Fraga
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela. Rúa Benigno Ledo S/n, 27002, Lugo, Spain
| | - Flora Alonso-Vega
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Roque Rodríguez-Soalleiro
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela. Rúa Benigno Ledo S/n, 27002, Lugo, Spain
| | - Esperanza Álvarez-Rodríguez
- Departamento de Edafología y Química Agrícola, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo S/n, 27002, Lugo, Spain
| | - Manuel Arias-Estévez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Juan Carlos Nóvoa-Muñoz
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
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23
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Zhou J, Bollen SW, Roy EM, Hollinger DY, Wang T, Lee JT, Obrist D. Comparing ecosystem gaseous elemental mercury fluxes over a deciduous and coniferous forest. Nat Commun 2023; 14:2722. [PMID: 37169778 PMCID: PMC10175444 DOI: 10.1038/s41467-023-38225-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 04/21/2023] [Indexed: 05/13/2023] Open
Abstract
Sources of neurotoxic mercury in forests are dominated by atmospheric gaseous elemental mercury (GEM) deposition, but a dearth of direct GEM exchange measurements causes major uncertainties about processes that determine GEM sinks. Here we present three years of forest-level GEM deposition measurements in a coniferous forest and a deciduous forest in northeastern USA, along with flux partitioning into canopy and forest floor contributions. Annual GEM deposition is 13.4 ± 0.80 μg m-2 (coniferous forest) and 25.1 ± 2.4 μg m-2 (deciduous forest) dominating mercury inputs (62 and 76% of total deposition). GEM uptake dominates in daytime during active vegetation periods and correlates with CO2 assimilation, attributable to plant stomatal uptake of mercury. Non-stomatal GEM deposition occurs in the coniferous canopy during nights and to the forest floor in the deciduous forest and accounts for 24 and 39% of GEM deposition, respectively. Our study shows that GEM deposition includes various pathways and is highly ecosystem-specific, which complicates global constraints of terrestrial GEM sinks.
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Affiliation(s)
- Jun Zhou
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Silas W Bollen
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
| | - Eric M Roy
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Ting Wang
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
| | - John T Lee
- School of Forest Resources, University of Maine, Orono, ME, USA
| | - Daniel Obrist
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA.
- University of California, Agriculture and Natural Resources, Davis, CA, USA.
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24
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Schneider L, Fisher JA, Diéguez MC, Fostier AH, Guimaraes JRD, Leaner JJ, Mason R. A synthesis of mercury research in the Southern Hemisphere, part 1: Natural processes. AMBIO 2023; 52:897-917. [PMID: 36943620 PMCID: PMC10073387 DOI: 10.1007/s13280-023-01832-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/30/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Recent studies demonstrate a short 3-6-month atmospheric lifetime for mercury (Hg). This implies Hg emissions are predominantly deposited within the same hemisphere in which they are emitted, thus placing increasing importance on considering Hg sources, sinks and impacts from a hemispheric perspective. In the absence of comprehensive Hg data from the Southern Hemisphere (SH), estimates and inventories for the SH have been drawn from data collected in the NH, with the assumption that the NH data are broadly applicable. In this paper, we centre the uniqueness of the SH in the context of natural biogeochemical Hg cycling, with focus on the midlatitudes and tropics. Due to its uniqueness, Antarctica warrants an exclusive review of its contribution to the biogeochemical cycling of Hg and is therefore excluded from this review. We identify and describe five key natural differences between the hemispheres that affect the biogeochemical cycling of Hg: biome heterogeneity, vegetation type, ocean area, methylation hotspot zones and occurence of volcanic activities. We review the current state of knowledge of SH Hg cycling within the context of each difference, as well as the key gaps that impede our understanding of natural Hg cycling in the SH. The differences demonstrate the limitations in using NH data to infer Hg processes and emissions in the SH.
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Affiliation(s)
- Larissa Schneider
- School of Culture, History and Language. Australian National University, Coombs Bld 9 Fellows Rd, Acton. Canberra, ACT 2601 Australia
| | - Jenny A. Fisher
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522 Australia
| | - María C. Diéguez
- Instituto de Investigaciones en Biodiversidad y Medioambiente (Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional del Comahue), 1250 San Carlos de Bariloche (8400), Quintral Argentina
| | - Anne-Hélène Fostier
- Instituto de Química/Unicamp, Rua Josué de Castro, s/n – Cidade Universitária, Campinas, SP 13083-970 Brazil
| | - Jean R. D. Guimaraes
- Lab. de Traçadores, Inst. de Biofísica, Bloco G, CCS (Centro de Ciências da Saúde), Av. Carlos Chagas Filho 373, Rio de Janeiro, Ilha do Fundão CEP 21941-902 Brazil
| | - Joy J. Leaner
- Department of Environmental Affairs and Development Planning, Western Cape Government, 1 Dorp Street, Western Cape, Cape Town, 8001 South Africa
| | - Robert Mason
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340 USA
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25
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Yuan T, Zhang P, Song Z, Huang S, Wang X, Zhang Y. Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5. ENVIRONMENT INTERNATIONAL 2023; 174:107904. [PMID: 37012193 DOI: 10.1016/j.envint.2023.107904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/04/2023] [Accepted: 03/26/2023] [Indexed: 06/19/2023]
Abstract
The vegetation uptake of atmospheric elemental mercury [Hg(0)] and its subsequent littering are critical processes of the terrestrial Hg cycles. There is a large uncertainty in the estimated global fluxes of these processes due to the knowledge gap in the underlying mechanisms and their relationship with environmental factors. Here, we develop a new global model based on the Community Land Model Version 5 (CLM5-Hg) as an independent component of the Community Earth System Model 2 (CESM2). We explore the global pattern of gaseous elemental Hg [Hg(0)] uptake by vegetation and the spatial distribution of litter Hg concentration constrained by observed datasets as well as its driving mechanism. The annual vegetation uptake of Hg(0) is estimated as 3132 Mg yr-1, which is considerably higher than previous global models. The scheme of dynamic plant growth including stomatal activities substantially improves the estimation for global terrestrial distribution of Hg, compared to the leaf area index (LAI) based scheme that is often used by previous models. We find the global distribution of litter Hg concentrations driven by vegetation uptake of atmospheric Hg(0), which are simulated to be higher in East Asia (87 ng/g) than in the Amazon region (63 ng/g). Meanwhile, as a significant source for litter Hg, the formation of structural litter (cellulose litter + lignin litter) results in a lagging effect between Hg(0) deposition and litter Hg concentration, implying the buffering effect of vegetation on the air-land exchange of Hg. This work highlights the importance of vegetation physiology and environmental factors in understanding the vegetation sequestration of atmospheric Hg globally, and calls for greater efforts to protect forests and afforestation.
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Affiliation(s)
- Tengfei Yuan
- School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Peng Zhang
- School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Zhengcheng Song
- School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Shaojian Huang
- School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Yanxu Zhang
- School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China.
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26
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Casagrande GCR, Dambros J, de Andrade EA, Martello F, Sobral-Souza T, Moreno MIC, Battirola LD, de Andrade RLT. Atmospheric mercury in forests: accumulation analysis in a gold mining area in the southern Amazon, Brazil. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:477. [PMID: 36928432 DOI: 10.1007/s10661-023-11063-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
The spatial distribution and dispersion of mercury (Hg) is associated with the structural conditions of the environment, primarily land use and vegetation cover. Man-made emissions of the metal from activities such as artisanal and small-scale gold mining (ASGM) can influence this distribution. Forest ecosystems are of particular importance as they constitute one of the most active environments in the biogeochemical cycle of Hg, and understanding these dynamics is essential to better understand its global cycle. In this study, we determined the content of Hg present in different forest strata (soil, leaf litter, herbaceous, underwood/bush, and arboreal), as well as the relationship between the presence of Hg and the landscape heterogeneity, percentage of gold mines, and ground slope. This study was carried out in tropical forest areas of the southern Brazilian Amazon. Accumulation and transport of Hg between forest strata was assessed in order to understand the influence of these forest environments on Hg accumulation in areas where ASGM occurs. We verified that there is a difference in Hg content between forest strata, indicating that atmospheric Hg is accumulated onto the arboreal stratum and transported vertically to strata below the canopy, i.e., underwood/bush and herbaceous, and subsequently accumulated in the leaf litter and transferred to the soil. Leaf litter was the stratum with the highest Hg content, characterized as a receptor for most of the Hg load from the upper strata in the forest. Therefore, it was confirmed that Hg accumulation dynamics are at play between the areas analyzed due to the proximity of ASGMs in the region. This indicates that the conservation of forest areas plays an important role in the process of atmospheric Hg deposition and accumulation, acting as a mercury sink in areas close to man-made emissions.
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Affiliation(s)
- Gabriela Cristina Rabello Casagrande
- Postgraduate Program in Biotechnology and Biodiversity-Rede Pró-Centro-Oeste, Federal University of Mato Grosso, Cuiabá Campus, Av. Fernando Corrêa da Costa, 2367, Bairro Boa Esperança, CEP 78060-900, Cuiabá, Mato Grosso, Brazil
| | - Juliane Dambros
- Postgraduate Program in Biotechnology and Biodiversity-Rede Pró-Centro-Oeste, Federal University of Mato Grosso, Cuiabá Campus, Av. Fernando Corrêa da Costa, 2367, Bairro Boa Esperança, CEP 78060-900, Cuiabá, Mato Grosso, Brazil
| | - Ednaldo Antônio de Andrade
- Institute of Agricultural and Environmental Sciences, Federal University of Mato Grosso, Sinop Campus, Av. Alexandre Ferronato, 1200, Setor Industrial, CEP 78557-267, Sinop, Mato Grosso, Brazil
| | - Felipe Martello
- Vale Institute of Technology-Sustainable Development, Rua Boaventura da Silva, 955, Nazaré, CEP 66055-090, Belém, Pará, Brazil
| | - Thadeu Sobral-Souza
- Department of Botany and Ecology, Federal University of Mato Grosso, Av. Fernando Corrêa da Costa 2367, Bairro Boa Esperança, CEP 78060-900, Cuiabá, Mato Grosso, Brazil
| | - Maria Inês Cruzeiro Moreno
- Departament of Biological Science, Institute of Biotechnology, Federal University of Catalão, Campus I, Av. Dr. Lamartine Pinto de Avelar, 1120 Setor Universitário, CEP 75704-020, Catalão, Goiás, Brazil
| | - Leandro Dênis Battirola
- Postgraduate Program in Biotechnology and Biodiversity-Rede Pró-Centro-Oeste, Federal University of Mato Grosso, Cuiabá Campus, Av. Fernando Corrêa da Costa, 2367, Bairro Boa Esperança, CEP 78060-900, Cuiabá, Mato Grosso, Brazil.
- Postgraduate Program in Environmental Science, Institute of Natural, Human and Social Sciences, Federal University of Mato Grosso, Sinop Campus, Av. Alexandre Ferronato, 1200, Setor Industrial, CEP 78557-267, Sinop, Mato Grosso, Brazil.
| | - Ricardo Lopes Tortorela de Andrade
- Postgraduate Program in Biotechnology and Biodiversity-Rede Pró-Centro-Oeste, Federal University of Mato Grosso, Cuiabá Campus, Av. Fernando Corrêa da Costa, 2367, Bairro Boa Esperança, CEP 78060-900, Cuiabá, Mato Grosso, Brazil
- Postgraduate Program in Environmental Science, Institute of Natural, Human and Social Sciences, Federal University of Mato Grosso, Sinop Campus, Av. Alexandre Ferronato, 1200, Setor Industrial, CEP 78557-267, Sinop, Mato Grosso, Brazil
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27
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Xin Y, Zhang X, Zheng D, Zhang Z, Jiang M. Impacts of spectral characteristics of dissolved organic matter on methylmercury contents in peatlands, Northeast China. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:913-923. [PMID: 35366716 DOI: 10.1007/s10653-022-01257-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Dissolved organic matter (DOM) plays an important role in promoting or suppressing methylmercury (MeHg) production in wetlands. However, the effects of DOM spectral characteristics on MeHg levels remain poorly understood in boreal peatlands in Northeast China, where is undergoing remarkable climate warming. In the present work, soil samples were collected from 22 peatlands in the Greater Khingan Mountains (GKM) to test the hypothesis that DOM spectral properties control MeHg levels. DOM was characterized by UV-Vis absorption and fluorescence spectroscopy; the three-dimensional fluorescence excitation-emission matrix (EEM) was used to unveil the origin of DOM. The average total mercury (THg) and MeHg contents were 112.76 µg/kg and 12.43 µg/kg across all peatlands, respectively. There was a significantly positive correlation between MeHg and the longitude spanning the range from 120 to 123°E (p < 0.05). Proportions of MeHg to THg (%MeHg), 12.3% on average, were positively correlated with DOM humification degree at p < 0.05 level. Protein-like components of DOM (P-like) were negatively related to %MeHg. DOM had positive effects on THg, and P-like components, HIX and BIX can negatively affect THg as well as MeHg. Our findings demonstrate that the spectral characteristics of DOM in soil are crucial to the content of methyl mercury in the GKM soil.
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Affiliation(s)
- Yuan Xin
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China
- Environmental College, Shenyang University, Shenyang, 110044, China
- Key Laboratory of Regional Environment and Eco-Remediation, Ministry of Education, Shenyang University, Shenyang, 110044, China
| | - Xuehui Zhang
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dongmei Zheng
- Environmental College, Shenyang University, Shenyang, 110044, China
- Key Laboratory of Regional Environment and Eco-Remediation, Ministry of Education, Shenyang University, Shenyang, 110044, China
| | - Zhongsheng Zhang
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China.
| | - Ming Jiang
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China
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28
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Méndez-López M, Parente-Sendín A, Calvo-Portela N, Gómez-Armesto A, Eimil-Fraga C, Alonso-Vega F, Arias-Estévez M, Nóvoa-Muñoz JC. Mercury in a birch forest in SW Europe: Deposition flux by litterfall and pools in aboveground tree biomass and soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:158937. [PMID: 36167130 DOI: 10.1016/j.scitotenv.2022.158937] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/15/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
Atmospheric mercury (Hg) is largely assimilated by vegetation and subsequently transferred to the soil by litterfall, which highlights the role of forests as one of the largest global Hg sinks within terrestrial ecosystems. We assessed the pool of Hg in the aboveground biomass (leaves, wood, bark, branches and twigs), the Hg deposition flux through litterfall over two years (by sorting fallen biomass in leaves, twigs, reproductive structures and miscellaneous) and its accumulation in the soil profile in a deciduous forest dominated by Betula alba from SW Europe. The total Hg pool in the aboveground birch biomass was in the range 532-683 mg ha-1, showing the following distribution by plant tissues: well-developed leaves (171 mg ha-1) > twigs (160 mg ha-1) > bark (159 mg ha-1) > bole wood (145 mg ha-1) > fine branches (25 mg ha-1) > thick branches (24 mg ha-1) > newly sprouted leaves (20 mg ha-1). The total Hg deposition fluxes through litterfall were 15.4 and 11.7 μg m-2 yr-1 for the two years studied, with the greatest contribution coming from birch leaves (73 %). In the soil profile, the pool of Hg in the mineral soil (37.0 mg m-2) was an order of magnitude higher than in the organic horizons (1.0 mg m-2), mostly conditioned by parameters such as soil bulk density and thickness, total C and N contents and the presence of certain Al compounds.
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Affiliation(s)
- Melissa Méndez-López
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain.
| | - Andrea Parente-Sendín
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - Noemi Calvo-Portela
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - Antía Gómez-Armesto
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - Cristina Eimil-Fraga
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo s/n, 27002 Lugo, Spain
| | - Flora Alonso-Vega
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - Manuel Arias-Estévez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - Juan Carlos Nóvoa-Muñoz
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
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29
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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. JOURNAL OF HAZARDOUS MATERIALS 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] [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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30
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Méndez-López M, Gómez-Armesto A, Eimil-Fraga C, Alonso-Vega F, Rodríguez-Soalleiro R, Álvarez-Rodríguez E, Arias-Estévez M, Nóvoa-Muñoz JC. Needle age and precipitation as drivers of Hg accumulation and deposition in coniferous forests from a southwestern European Atlantic region. ENVIRONMENTAL RESEARCH 2022; 215:114223. [PMID: 36063908 DOI: 10.1016/j.envres.2022.114223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/29/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Vegetation and climate are critical in the biogeochemical cycle of Hg in forest ecosystems. The study assesses the influence of needle age and precipitation on the accumulation of Hg in needle biomass and its deposition by litterfall in thirty-one pine plantations spread throughout two biogeographical regions in SW Europe. Well-developed branches of Pinus pinaster were sampled and pine needles were classified according to 4 age classes (y0, y1, y2, y3). The concentration of total Hg (THg) was analyzed in the samples and Hg content in needle biomass and its deposition by litterfall were estimated. The concentration of total Hg (THg) increased with needle age ranging from 9.1 to 32.7 μg Hg kg-1 in the youngest and oldest needles, respectively. The rate of Hg uptake (HgR) three years after needle sprouting was 10.2 ± 2.3 μg Hg kg-1 yr-1, but it decreased with needle age probably due to a diminution in photosynthetic activity as needles get older. The average total Hg stored in needle biomass (HgWt) ranged from 5.6 to 87.8 mg Hg ha-1, with intermediate needle age classes (y1 and y2) accounting for 70% of the total Hg stored in the whole needle biomass. The average deposition flux of Hg through needle litterfall (HgLt) was 1.5 μg Hg m-2 yr-1, with the y2 and y3 needles contributing most to the total Hg flux. The spatial variation of THg, HgWt and HgLt decreased from coastal pine stands, characterized by an oceanic climate, to inland pine stands, a feature closely related to the dominant precipitation regime in the study area. Climatic conditions and needle age are the main factors affecting Hg accumulation in tree foliage, and should be considered for an accurate assessment of forest Hg pools at a regional scale and their potential consequences in the functioning of terrestrial ecosystems.
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Affiliation(s)
- Melissa Méndez-López
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain.
| | - Antía Gómez-Armesto
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Cristina Eimil-Fraga
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo s/n, 27002, Lugo, Spain
| | - Flora Alonso-Vega
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Roque Rodríguez-Soalleiro
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo s/n, 27002, Lugo, Spain
| | - Esperanza Álvarez-Rodríguez
- Departamento de Edafología y Química Agrícola, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo s/n, 27002, Lugo, Spain
| | - Manuel Arias-Estévez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Juan Carlos Nóvoa-Muñoz
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
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31
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Xia J, Wang J, Zhang L, Wang X, Yuan W, Peng T, Zheng L, Tian W, Feng X. Migration and transformation of soil mercury in a karst region of southwest China: Implications for groundwater contamination. WATER RESEARCH 2022; 226:119271. [PMID: 36283232 DOI: 10.1016/j.watres.2022.119271] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Guizhou Province is located in the heart of a karst zone in southwest China, which is one of the largest karst areas in the world. Given the fragile surface ecosystem and highly developed underground karst structure, the migration and transformation of soil Hg may impact groundwater quality in karst environments with high Hg background concentrations. This study examines the vertical migration and transformation of soil mercury (Hg) in two karst catchments, Huilong and Chenqi, with the former containing high Hg contents associated with mineralization and the latter representing regional background Hg. The results show that the soil Hg pool in the Huilong catchment was as high as 44.4 ± 4.2 g m-2, whereas in the Chenqi catchment was only 0.17±0.02 g m-2. Compared with farmland soil, forest soil showed a significant loss of Hg. The results of L3 X-ray absorption near edge structure of Hg indicated that α-HgS, the primary mineral of Hg ore, gradually changed to other mineral types during soil formation. In Huilong catchment, the proportion of organic bound Hg(SR)2 out of total Hg decreased from 44.0% to 20.3% when soil depth increased from 10 cm to 160 cm in farmland soil profile and from 39.3% to 34.5% in forest soil profile, while the proportion of ionic Hg increased with soil depth, from 4.2% to 10.7% in the farmland soil profile and from 6.7% to 11.6% in the forestland soil profile. Results from the triple-mixing isotope model show that soil Hg accounts for more than 80% Hg in groundwater in the two catchments. Results from this study indicate potential risks of soil Hg entering into groundwater in this karst area.
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Affiliation(s)
- Jicheng Xia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianxu Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, ON M3H 5T4, Canada
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Tao Peng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, Puding 562100, China
| | - Lirong Zheng
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Weijun Tian
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
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32
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Bardelli F, Rimondi V, Lattanzi P, Rovezzi M, Isaure MP, Giaccherini A, Costagliola P. Pinus nigra bark from a mercury mining district studied with high resolution XANES spectroscopy. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1748-1757. [PMID: 35972271 DOI: 10.1039/d2em00239f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Tree bark near former mercury (Hg) mines and roasting plants is known to have exceptionally high (up to several mg kg-1) Hg concentrations. This study explores the change of Hg speciation with depth (down to 25-30 mm from the outermost surface) in black pine (Pinus nigra) bark by means of high-resolution X-ray absorption near edge structure (HR-XANES) spectroscopy at the Hg LIII-edge. Principal component analysis and linear combination fitting applied to the HR-XANES spectra suggested that in the outermost layer (∼0-2 mm from the surface), roughly 50% of Hg is in the form of nanoparticulate metacinnabar (nano-β-HgS). A progressive increase in Hg-organic species (Hg bound to thiol groups) is found in deeper bark layers, while nano-β-HgS may decrease below the detection limit in the deepest layers. Notably, bark layers did not contain cinnabar (α-HgS), which was found in the nearby soils along with β-HgS (bulk), nor Hg0, which is the main Hg species in the atmosphere surrounding the sampled trees. These observations suggested that nano-β-HgS, at least in part, does not originate from mechanically trapped wind-blown particulates from the surrounding soil, but may be the product of biochemical reactions between gaseous elemental Hg and the bark tissue.
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Affiliation(s)
| | | | | | - Mauro Rovezzi
- Univ. Grenoble Alpes, CNRS, IRD, Irstea, OSUG, FAME, Météo France, Grenoble, France.
| | - Marie-Pierre Isaure
- Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Pau, France.
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33
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Yuan W, Wang X, Lin CJ, Wu F, Luo K, Zhang H, Lu Z, Feng X. Mercury Uptake, Accumulation, and Translocation in Roots of Subtropical Forest: Implications of Global Mercury Budget. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14154-14165. [PMID: 36150175 DOI: 10.1021/acs.est.2c04217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Plant roots are responsible for transporting large quantities of nutrients in forest ecosystems and yet are frequently overlooked in global assessments of Hg cycling budgets. In this study, we systematically determined the distribution of total Hg mass and its stable isotopic signatures in a subtropical evergreen forest to elucidate sources of Hg in plant root tissues and the associated translocation mechanisms. Hg stored in roots and its isotopic signatures show significant correlations to those found in surrounding soil at various soil depths. The odd mass-independent fractionation (MIF) of root Hg at a shallow soil depth displays a -0.10‰ to -0.50‰ negative transition compared to the values in aboveground woody biomass. The evidence suggests that root Hg is predominantly derived from surrounding soil, rather than translocation of atmospheric uptake via aboveground tissues. The cortex has a more negative mass-dependent fractionation (MDF) of -0.10‰ to -1.20‰ compared to the soil samples, indicating a preferential uptake of lighter isotopes by roots. The similar MDF and odd-MIF signals found in root components imply limited Hg transport in roots. This work highlights that Hg stored in plant roots is not a significant sink of atmospheric Hg. The heterogeneous distribution of Hg mass in roots of various sizes represents a significant uncertainty of current estimates of Hg pool size in forest ecosystems.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kang Luo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Zhiyun Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China
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34
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Feinberg A, Dlamini T, Jiskra M, Shah V, Selin NE. Evaluating atmospheric mercury (Hg) uptake by vegetation in a chemistry-transport model. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1303-1318. [PMID: 35485923 PMCID: PMC9491292 DOI: 10.1039/d2em00032f] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Mercury (Hg), a neurotoxic heavy metal, is transferred to marine and terrestrial ecosystems through atmospheric transport. Recent studies have highlighted the role of vegetation uptake as a sink for atmospheric elemental mercury (Hg0) and a source of Hg to soils. However, the global magnitude of the Hg0 vegetation uptake flux is highly uncertain, with estimates ranging 1000-4000 Mg per year. To constrain this sink, we compare simulations in the chemical transport model GEOS-Chem with a compiled database of litterfall, throughfall, and flux tower measurements from 93 forested sites. The prior version of GEOS-Chem predicts median Hg0 dry deposition velocities similar to litterfall measurements from Northern hemisphere temperate and boreal forests (∼0.03 cm s-1), yet it underestimates measurements from a flux tower study (0.04 cm s-1vs. 0.07 cm s-1) and Amazon litterfall (0.05 cm s-1vs. 0.17 cm s-1). After revising the Hg0 reactivity within the dry deposition parametrization to match flux tower and Amazon measurements, GEOS-Chem displays improved agreement with the seasonality of atmospheric Hg0 observations in the Northern midlatitudes. Additionally, the modelled bias in Hg0 concentrations in South America decreases from +0.21 ng m-3 to +0.05 ng m-3. We calculate a global flux of Hg0 dry deposition to land of 2276 Mg per year, approximately double previous model estimates. The Amazon rainforest contributes 29% of the total Hg0 land sink, yet continued deforestation and climate change threatens the rainforest's stability and thus its role as an important Hg sink. In an illustrative worst-case scenario where the Amazon is completely converted to savannah, GEOS-Chem predicts that an additional 283 Mg Hg per year would deposit to the ocean, where it can bioaccumulate in the marine food chain. Biosphere-atmosphere interactions thus play a crucial role in global Hg cycling and should be considered in assessments of future Hg pollution.
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Affiliation(s)
- Aryeh Feinberg
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Thandolwethu Dlamini
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Martin Jiskra
- Environmental Geosciences, University of Basel, Basel, Switzerland
| | - Viral Shah
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Noelle E Selin
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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35
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Xu Z, Wang Z, Zhang X. Mapping the forest litterfall mercury deposition in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:156288. [PMID: 35644398 DOI: 10.1016/j.scitotenv.2022.156288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/26/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Litterfall mercury (Hg) deposition represents one of the biggest Hg inputs to forest ecosystems through assimilation of atmospheric gaseous elemental Hg (Hg0) to foliage. However, due to the availability of litterfall production and Hg concentration data, a comprehensive quantification of litterfall Hg deposition is still lacking in China. In this study, the forest litterfall production of five major forest types in China was modeled by using the random forest (RF) method and multi-source datasets. A substantial nationwide dataset of litterfall Hg concentration was compiled including the investigation of our research group and previous published data. The litterfall Hg flux of forest was quantified by integrating litterfall production map and litterfall Hg concentration data. The nationwide litterfall Hg concentration ranged from 12.75 to 178.00 ng g-1 with a mean of 51.99 ± 34.23 ng g-1. For litterfall production, the mean value was simulated to be 5.07 Mg ha-1 yr-1, with the highest values in tropical areas and the lowest in the northeast and northwest arid regions. The litterfall Hg flux of forest in China was characterized by high in the south and low in the north, ranging from 5.57 to 137.05 μg m-2 yr-1, with an average value of 25.88 ± 12.53 μg m-2 yr-1. Total Hg deposition from forest litterfall in China was estimated to be 27.0 ± 13.0 Mg yr-1, and that of evergreen broadleaf forest, mixed forest, deciduous broadleaf forest, evergreen needleleaf forest and deciduous needleleaf forest were 10.8 ± 5.3 Mg yr-1, 8.5 ± 4.0 Mg yr-1, 6.1 ± 2.6 Mg yr-1, 1.5 ± 1.0 Mg yr-1 and 0.2 ± 0.1 Mg yr-1, respectively. This is the primary quantitative evaluation of the forest litterfall Hg deposition in China, which is essential for understanding the role and status of Chinese forest in the global Hg cycle.
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Affiliation(s)
- Zehua Xu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhangwei Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoshan Zhang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Zhang F, Xu Z, Xu X, Liang L, Chen Z, Dong X, Luo K, Dinis F, Qiu G. Terrestrial mercury and methylmercury bioaccumulation and trophic transfer in subtropical urban forest food webs. CHEMOSPHERE 2022; 299:134424. [PMID: 35351481 DOI: 10.1016/j.chemosphere.2022.134424] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
As the "lungs of the city", urban forests can improve air quality by absorbing air pollutants, becoming hotspots for mercury (Hg) pollution from anthropogenic activities. However, the bioaccumulation and transfer of Hg in the urban forest food web are unclear. In this study, total mercury (THg) and methylmercury (MeHg) concentrations, as well as the stable isotopes of carbon (δ13C) and nitrogen (δ15N) in organisms with different trophic levels (TLs) were investigated in a mid-subtropical urban forest of the Changpoling Forest Park (CFP) in Guiyang City, Guizhou Province, southwestern China. The results showed that THg and MeHg among all taxa ranged from 5.6 to 1267 ng g-1 and 0.046-692 ng g-1, respectively. MeHg% (% of Hg present as MeHg) at different TLs exhibited a wide range of 5.0-69% on average. Both THg and MeHg increased with the TLs from plants to nestling birds, indicating distinct biomagnification through the food web of grasses/pine needles - grasshoppers/caterpillars/katydids/mantis - spiders/songbird nestlings. The trophic magnification slope (TMS) of THg and MeHg were 0.18 ± 0.05 and 0.37 ± 0.08, respectively, suggesting both of them significantly increase along food webs. These findings improve the understanding of biogeochemical Hg cycles in terrestrial food webs and highlight the impacts of terrestrial MeHg on nestling birds.
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Affiliation(s)
- Fudong Zhang
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Zhidong Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Xiaohang Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Longchao Liang
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Zhuo Chen
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China.
| | - Xian Dong
- School of Chemistry and Materials Science, Guizhou Normal University, Guiyang, 550001, China
| | - Kang Luo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, 676200, China
| | - Faustino Dinis
- College of Agriculture, Guizhou University, Guiyang, 550025, China
| | - Guangle Qiu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
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37
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Méndez-López M, Gómez-Armesto A, Alonso-Vega F, Pontevedra-Pombal X, Fonseca F, de Figueiredo T, Arias-Estévez M, Nóvoa-Muñoz JC. The role of afforestation species as a driver of Hg accumulation in organic horizons of forest soils from a Mediterranean mountain area in SW Europe. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 827:154345. [PMID: 35257764 DOI: 10.1016/j.scitotenv.2022.154345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/10/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Forest areas are a primary sink of atmospheric mercury (Hg) within terrestrial ecosystems, whereas forest vegetation plays a key role in atmospheric Hg transfer to soil horizons. This study assessed variations in total Hg contents (HgT) and accumulation (HgRes) in the soil organic horizons of a forest area in NE Portugal, where post-wildfire afforestation led to the substitution of the native deciduous species (Quercus pyrenaica) by fast-growing coniferous species (Pseudotsuga menziesii and Pinus nigra). The study also evaluated, for each species, the links between Hg contents and other biophilic elements of soil organic matter (C, N, S) present in organic subhorizons (OL, OF, OH). Mean HgT in the organic horizons of the different tree species follow the sequence: P. nigra (88 μg kg-1) < Q.pyrenaica (101 μg kg-1) <P. menziesii (141 μg kg-1). The highest HgRes for the entire organic horizon was found under P. menziesii (471 μg m-2), followed by P. nigra (253 μg m-2) and Q. pyrenaica (189 μg m-2). Among the organic subhorizons, values of HgT and HgRes follow the sequence OL < OF < OH, which is consistent with the degree of organic matter humification. Indeed, HgT and HgRes correlated significantly with the C/N and C/S ratios for all species and organic subhorizons, suggesting that the quality of organic matter may influence strongly the Hg fate in these forest soils. Soils from P. menziesii plots have shown an HgRes 2.5 times higher than in plots dominated by the native Q. pyrenaica. Hg accumulation in the organic horizons, promoted in the coniferous species, may increase the risk of Hg mobilization due to wildfires and forest management practices. Therefore, forest management plans should select cautiously the tree species for afforestation in order to minimize adverse environmental effects caused by changes in the biogeochemical cycle of contaminants such as Hg.
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Affiliation(s)
- M Méndez-López
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain.
| | - A Gómez-Armesto
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - F Alonso-Vega
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - X Pontevedra-Pombal
- Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, 15786 Santiago de Compostela, Spain
| | - F Fonseca
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Sta Apolónia, 5300-253 Bragança, Portugal
| | - T de Figueiredo
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Sta Apolónia, 5300-253 Bragança, Portugal
| | - M Arias-Estévez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
| | - J C Nóvoa-Muñoz
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004 Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004 Ourense, Spain
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Feng X, Li P, Fu X, Wang X, Zhang H, Lin CJ. Mercury pollution in China: implications on the implementation of the Minamata Convention. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:634-648. [PMID: 35485580 DOI: 10.1039/d2em00039c] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mercury (Hg) is a toxic metal released into the environment through human activities and natural processes. Human activities have profoundly increased the amount of Hg in the atmosphere and altered its global cycling since the Industrial Revolution. Gaseous elemental Hg is the predominant form of Hg in the atmosphere, which can undergo long-range transport and atmospheric deposition into the aquatic systems. Hg deposition elevates the methylmercury (MeHg) level in fish through bioaccumulation and biomagnification, which poses a serious human health risk. Acute poisoning of MeHg can result in Minamata disease, while low-level long-term exposure in pregnant women can reduce the intelligence quotient of infants. After five sessions of intergovernmental negotiation, the Minamata Convention on mercury entered into force in August 2017 to protect human health and the environment from Hg pollution. Currently China contributes the largest quantity of Hg production, consumption, and emission globally. However, the status of Hg pollution in the environment in China and its associated health risk remains relatively unknown, which hinders the development of implementation plans of the Minamata Convention. In this paper, we provide a comprehensive review on the atmospheric release of Hg, distribution of air Hg concentration, human exposure to MeHg and health impacts caused by Hg pollution in China. Ongoing improvement of air pollution control measures is expected to further decrease anthropogenic Hg emissions in China. Air Hg concentrations in China are higher than the background values in the Northern Hemisphere, with spatial distribution largely influenced by anthropogenic emissions. Long-term observations of GEM in China show a decline in recent years. The net Hg transport outflow from China in 2013 is estimated to be 511 t year-1, and ∼60% of such outflow is caused by natural surface Hg emissions. Hg concentrations in fish and rice in China are relatively low and therefore the associated risks of human Hg exposure are low. Future research needs and recommendations for the implementation of the Minamata Convention are also discussed in this paper.
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Affiliation(s)
- Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Ping Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Hua Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, USA
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39
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Xia S, Yuan W, Lin L, Yang X, Feng X, Li X, Liu X, Chen P, Zeng S, Wang D, Su Q, Wang X. Latitudinal gradient for mercury accumulation and isotopic evidence for post-depositional processes among three tropical forests in Southwest China. JOURNAL OF HAZARDOUS MATERIALS 2022; 429:128295. [PMID: 35074747 DOI: 10.1016/j.jhazmat.2022.128295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/04/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Tropical forest contributes to > 50% of global litterfall mercury (Hg) inputs and surface soil Hg storage, while with limited understanding of Hg biogeochemical processes. In this study, we displayed the 5-m resolution of Hg spatial distribution in three 1-ha tropical forest plots across the latitudinal gradient in Southwest China, and determined Hg isotopic signatures to understand factors driving Hg spatial distribution and sequestration processes. Our results show that tropical forest at the lowest latitude has the highest litterfall Hg input (74.95 versus 34.14-56.59 μg m-2 yr-1 at higher latitude plots), but the smallest surface soil Hg concentration (2-3 times smaller than at higher latitude sites). Hg isotopic evidence indicates that the decreasing climate mediated microbial Hg reduction in forest floor leads to the increasing Hg accumulation along the latitudinal gradient in three tropical forests. The terrain induced indirect effects by influencing litterfall Hg inputs, soil organic matters distribution and interplays between surface and deep soils drive the heterogeneity of surface soil Hg distribution within each sampling plot. Our results highlight though the elevated litterfall Hg inputs, the distinct post-depositional reductions induced Hg loss would remarkedly decrease atmospheric Hg net sink in tropical forest.
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Affiliation(s)
- Shangwen Xia
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Luxiang Lin
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China; National Forest Ecosystem Research Station at Xishuangbanna, Mengla 666300, Yunnan, China
| | - Xiaodong Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xianming Li
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xu Liu
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Peijia Chen
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Shufang Zeng
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qizhao Su
- Mengla Institute of Conservation, Xishuangbanna Administration of Nature Reserves, Mengla 666300, Yunan, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
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Wang B, Yuan W, Wang X, Li K, Lin CJ, Li P, Lu Z, Feng X, Sommar J. Canopy-Level Flux and Vertical Gradients of Hg 0 Stable Isotopes in Remote Evergreen Broadleaf Forest Show Year-Around Net Hg 0 Deposition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5950-5959. [PMID: 35420795 DOI: 10.1021/acs.est.2c00778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Vegetation uptake represents the dominant route of Hg input to terrestrial ecosystems. However, this plant-directed sink is poorly constrained due to the challenges in measuring the net Hg0 exchange on the ecosystem scale over a long period. Particularly important is the contribution in the subtropics/tropics, where the bulk (∼70%) of the Hg0 deposition is considered to occur. Using the relaxed eddy accumulation technique, this study presents for the first time a whole ecosystem Hg0 flux record over an evergreen hardwood forest. This tower-based micrometeorological method gauged a cumulated net Hg0 flux of -41.1 μg m-2 over 16 months, suggesting that the subtropical montane forest acts as a large and continuous sink of atmospheric Hg0. The monthly net fluxes were consistently negative (-7.3 to -1.0 μg m-2 month-1) throughout the year, with the smallest absolute values occurring during the mild and dry subseason in spring, which was also the annual lowest in vegetation activity. Colocated measurements of multilevel gradients of Hg0 concentration and its stable isotopic composition support the finding of year-round Hg0 deposition. The stable Hg isotope measurements also show that in-canopy bi-directional Hg0 exchange is prevalent.
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Affiliation(s)
- Bo Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Kai Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Ping Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xian 710061, China
| | - Zhiyun Lu
- National Forest Ecosystem Research Station at Ailaoshan, Jingdong, Yunnan 676209, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xian 710061, China
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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Evans MN, Waller S, Müller CT, Goossens B, Smith JA, Bakar MSA, Kille P. The price of persistence: Assessing the drivers and health implications of metal levels in indicator carnivores inhabiting an agriculturally fragmented landscape. ENVIRONMENTAL RESEARCH 2022; 207:112216. [PMID: 34656630 DOI: 10.1016/j.envres.2021.112216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/17/2021] [Accepted: 10/11/2021] [Indexed: 06/13/2023]
Abstract
Patterns and practices of agricultural expansion threaten the persistence of global biodiversity. Wildlife species surviving large-scale land use changes can be exposed to a suite of contaminants that may deleteriously impact their health. There is a paucity of data concerning the ecotoxicological impacts associated with the global palm oil (Elaeis guineensis) industry. We sampled wild Malay civets (Viverra tangalunga) across a patchwork landscape degraded by oil palm agriculture in Sabah, Malaysian Borneo. Using a non-lethal methodology, we quantified the levels of 13 essential and non-essential metals within the hair of this adaptable small carnivore. We robustly assessed the biological and environmental drivers of intrapopulation variation in measured levels. Metal concentrations were associated with civet age, weight, proximity to a tributary, and access to oxbow lakes. In a targeted case study, the hair metal profiles of 16 GPS-collared male civets with differing space use patterns were contrasted. Civets that entered oil palm plantations expressed elevated aluminium, cadmium, and lead, and lower mercury hair concentrations compared to civets that remained exclusively within the forest. Finally, we paired hair metal concentrations with 34 blood-based health markers to evaluate the possible sub-lethal physiological effects associated with varied hair metal levels. Our multi-facetted approach establishes these adaptable carnivores as indicator species within an extensively altered ecosystem, and provides critical and timely evidence for future studies.
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Affiliation(s)
- Meaghan N Evans
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK; Danau Girang Field Centre, Kota Kinabalu, 88100, Malaysia.
| | - Simon Waller
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | - Carsten T Müller
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
| | - Benoit Goossens
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK; Danau Girang Field Centre, Kota Kinabalu, 88100, Malaysia; Sustainable Places Institute, Cardiff University, Cardiff, CF10 3BA, UK; Sabah Wildlife Department, Kota Kinabalu, 88100, Malaysia
| | - Jeremy A Smith
- School of Applied Sciences, University of South Wales, CF37 4BB, UK
| | | | - Peter Kille
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.
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Kodamatani H, Shigetomi A, Akama J, Kanzaki R, Tomiyasu T. Distribution, alkylation, and migration of mercury in soil discharged from the Itomuka mercury mine. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 815:152492. [PMID: 34958844 DOI: 10.1016/j.scitotenv.2021.152492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/05/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
The purpose of this study was to investigate the behavior of previously discharged mercury (Hg) released from the Itomuka Hg mine into the surrounding environment, especially into soil. Total-Hg (T-Hg), methylmercury (MeHg), and ethylmercury (EtHg) concentrations in the surface soil at eight sample sites around the mine were 3.8-64.2 mg/kg, 6.0-54.7 μg/kg, and undetected to 4.5 μg/kg, respectively. Core samples collected from seven of the eight sample sites showed that the vertical distribution of T-Hg was the highest in the surface soil layer and decreased rapidly in the lower layers. A strong positive correlation was observed between T-Hg and MeHg concentrations in the core samples; however, the slope of the regression line varied considerably for each core. This suggests that Hg and MeHg were not supplied from the atmosphere simultaneously, but rather that MeHg was produced on-site. Further, the formation of MeHg and EtHg in soil was considered in terms of the total organic carbon/total nitrogen ratio, which is a decomposition index of soil organic matter. The strong positive correlation between T-Hg and MeHg can be attributed to the migration of organic matter containing Hg species to the lower layers. There was no relationship between T-Hg and MeHg at the riverbed sample site because of the high T-Hg in the lower soil layers, suggesting that Hg was supplied by ore at this sample site. These assumptions of the formation change and migration of Hg in soil were supported by the results of the fractionation experiment and the elution test. To understand the current conditions in this area, measurements of Hg in the water, sediment, atmosphere, and plants were also conducted.
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Affiliation(s)
- Hitoshi Kodamatani
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan.
| | - Azusa Shigetomi
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
| | - Junna Akama
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
| | - Ryo Kanzaki
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
| | - Takashi Tomiyasu
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
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Liu Y, Wang J, Guo J, Wang L, Wu Q. Vertical distribution characteristics of soil mercury and its formation mechanism in permafrost regions: A case study of the Qinghai-Tibetan Plateau. J Environ Sci (China) 2022; 113:311-321. [PMID: 34963540 DOI: 10.1016/j.jes.2021.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 06/14/2023]
Abstract
Continuing permafrost degradation is increasing the risk of mercury (Hg) exposure in the permafrost regions on the Qinghai-Tibetan Plateau (QTP), but related studies are still limited, especially the ones on the detailed Hg migration processes in permafrost. The vertical distribution characteristics of soil Hg were investigated in three ecosystems in the Beiluhe area on the QTP, and its influencing factors and formation mechanism were investigated. The results indicate that the total soil mercury (THg) concentration in the Beiluhe area remains at an extremely low level (6.33 ± 2.45 ng/g). In the vertical profile, the THg concentration of the shallow soil layer (0-50 cm) (5.96 ± 2.22 ng/g) is significantly lower than that of the deep layer (50-400 cm) (7.44 ± 2.71 ng/g) (p < 0.05). Within the upper 50 cm, the THg concentration decreases with soil depth, and the peak THg concentration occurs at 100-300 cm on the entire profile. Although the THg concentration is slightly affected by the organic matter in the shallow soil layer, in general, the soil parent material is the dominant factor affecting the THg concentration. Intense weathering results in a low THg concentration in the shallow soil layer because the soil Hg is carried downward with the soil moisture. To a certain depth, the impermeable frozen soil layer intercepts the flow of the soil Hg, and it forms a Hg enrichment layer. This paper presents the distinctive pattern of the soil Hg distribution in the permafrost regions of the QTP.
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Affiliation(s)
- Yali Liu
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junfeng Wang
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Junming Guo
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China
| | - Luyang Wang
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingbai Wu
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
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Yu B, Yang L, Liu H, Xiao C, Bu D, Zhang Q, Fu J, Zhang Q, Cong Z, Liang Y, Hu L, Yin Y, Shi J, Jiang G. Tracing the Transboundary Transport of Mercury to the Tibetan Plateau Using Atmospheric Mercury Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1568-1577. [PMID: 35001617 DOI: 10.1021/acs.est.1c05816] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Deposition of atmospheric mercury (Hg) is the most important Hg source on the high-altitude Himalayas and Tibetan Plateau. Herein, total gaseous Hg (TGM) at an urban and a forest site on the Tibetan Plateau was collected respectively from May 2017 to October 2018, and isotopic compositions were measured to clarify the influences of landforms and monsoons on the transboundary transport of atmospheric Hg to the Tibetan Plateau. The transboundary transported anthropogenic emissions mainly originated over Indo-Gangetic Plain and carried over the Himalayas by convective storms and mid-tropospheric circulation, contributing over 50% to the TGM at the Lhasa urban site, based on the binary mixing model of isotopes. In contrast, during the transport of TGM from South Asia with low altitude, the uptake by evergreen forest in Yarlung Zangbo Grand Canyon largely decreased the TGM level and shifted isotopic compositions in TGM at the Nyingchi forest site, which are located at the high-altitude end of the canyon. Our results provided direct evidence from Hg isotopes to reveal the distinct patterns of transboundary transport to the Tibetan Plateau shaped by landforms and climates, which is critical to fully understand the biogeochemical cycling of Hg in the high-altitude regions.
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Affiliation(s)
- Ben Yu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- National Research Center for Environmental Analysis and Measurement, Beijing 100029, China
| | - Lin Yang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hongwei Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Cailing Xiao
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Duo Bu
- Science Faculty, Tibet University, Lhasa 850000, China
| | | | - Jianjie Fu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310000, China
| | - Qianggong Zhang
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhiyuan Cong
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Yong Liang
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Ligang Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310000, China
| | - Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310000, China
| | - Jianbo Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310000, China
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310000, China
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
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45
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Wang T, Obrist D. Inorganic and methylated mercury dynamics in estuarine water of a salt marsh in Massachusetts, USA. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 294:118657. [PMID: 34890749 DOI: 10.1016/j.envpol.2021.118657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 11/06/2021] [Accepted: 12/06/2021] [Indexed: 05/26/2023]
Abstract
Salt marsh estuaries serve as sources and sinks for nutrients and elements to and from estuarine water, which enhances and alleviates watershed fluxes to the coastal ocean. We assessed sources and sinks of mercury in the intertidal Plum Island Sound estuary in Massachusetts, the largest salt marsh estuary of New England, using 25-km spatial water sampling transects. Across all seasons, dissolved (FHg) and total (THg) mercury concentrations in estuarine water were highest and strongly enhanced in upper marshes (1.31 ± 0.20 ng L-1 and 6.56 ± 3.70 ng L-1, respectively), compared to riverine Hg concentrations (0.86 ± 0.17 ng L-1 and 0.88 ± 0.34 ng L-1, respectively). Mercury concentrations declined from upper to lower marshes and were lowest in ocean water (0.38 ± 0.10 ng L-1 and 0.56 ± 0.25 ng L-1, respectively). Conservative mixing models using river and ocean water as endmembers indicated that internal estuarine Hg sources strongly enhanced estuarine water Hg concentrations. For FHg, internal estuarine Hg contributions were estimated at 26 g yr-1 which enhanced Hg loads from riverine sources to the ocean by 44%. For THg, internal sources amounted to 251 g yr-1 and exceeded riverine sources six-fold. Proposed sources for internal estuarine mercury contributions include atmospheric deposition to the large estuarine surface area and sediment re-mobilization, although sediment Hg concentrations were low (average 23 ± 2 μg kg-1) typical of uncontaminated sediments. Soil mercury concentrations under vegetation, however, were ten times higher (average 200 ± 225 μg kg-1) than in intertidal sediments suggesting that high soil Hg accumulation might drive lateral export of Hg to the ocean. Spatial transects of methylated Hg (MeHg) showed no concentration enhancements in estuarine water and no indication of internal MeHg sources or formation. Initial mass balance considerations suggest that atmospheric deposition may either be in similar magnitude, or possibly exceed lateral tidal export which would be consistent with strong Hg accumulation observed in salt marsh soils sequestering Hg from current and past atmospheric deposition.
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Affiliation(s)
- Ting Wang
- Department of Environmental, Earth, and Atmospheric Sciences, University of Massachusetts Lowell, Lowell, MA, 01854, USA.
| | - Daniel Obrist
- Department of Environmental, Earth, and Atmospheric Sciences, University of Massachusetts Lowell, Lowell, MA, 01854, USA.
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Li X, Wang X, Yuan W, Lu Z, Wang D. Increase of litterfall mercury input and sequestration during decomposition with a montane elevation in Southwest China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 292:118449. [PMID: 34740733 DOI: 10.1016/j.envpol.2021.118449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/27/2021] [Accepted: 10/30/2021] [Indexed: 06/13/2023]
Abstract
Litterfall mercury (Hg) input has been regarded as the dominant Hg source in montane forest floor. To depict combining effects of vegetation, climate and topography on accumulation of Hg in montane forests, we comprehensively quantified litterfall Hg deposition and decomposition in a serial of subtropical forests along an elevation gradient on both leeward and windward slopes of Mt. Ailao, Southwest China. Results showed that the average litterfall Hg deposition increased from 12.0 ± 4.2 μg m-2 yr-1 in dry-hot valley shrub at 850-1000 m, 14.9 ± 6.8 μg m-2 yr-1 in mixed conifer-broadleaf forest at 1250-2400 m, to 23.1 ± 8.3 μg m-2 yr-1 in evergreen broadleaf forest at 2500-2650 m. Additionally, the windward slope forests had a significantly higher litterfall Hg depositions at the same altitude because the larger precipitation promoted the greater litterfall biomass production. The one-year litter Hg decomposition showed that the Hg mass of litter in dry-hot valley shrub decreased by 29%, while in mixed conifer-broadleaf and evergreen broadleaf forests increased by 22-48%. The dynamics of Hg in decomposing litter was controlled by the temperature mediated litter decomposition rate and the additional adsorption of environmental Hg during decomposition. Overall, our study highlights the litterfall mediated atmospheric mercury inputs and sequestration increase with the montane elevation, thus driving a Hg enhanced accumulation in the high montane forest.
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Affiliation(s)
- Xianming Li
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Zhiyun Lu
- Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, Yunnan, 676200, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China.
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Castro S, Luiz-Silva W, Machado W, Valezio E. Mangrove sediments as long-term mercury sinks: Evidence from millennial to decadal time scales. MARINE POLLUTION BULLETIN 2021; 173:113031. [PMID: 34656863 DOI: 10.1016/j.marpolbul.2021.113031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/30/2021] [Accepted: 10/02/2021] [Indexed: 06/13/2023]
Abstract
The mercury (Hg) cycle in estuaries has been globally discussed, although Holocene deposition in mangrove sediments remains unknown. Herein, a sediment core from a mangrove system in southeastern Brazil was 14C-dated to evaluate millennial Hg deposition. The highest Hg concentrations (1010-2540 ng g-1) in surface sediments were explained by emissions from a chlor-alkali industry (1964 CE). However, Hg levels were also high in pre-industrial periods, associated to fine grain-size and algal organic deposition. Less anomalous Hg concentrations in bottom sediments indicate Holocene ages (~1940-3324 cal yr BP), potentially associated to Serra do Mar mountains weathering. This study reveals the capacity of mangrove to retain Hg over millennial time scales, acting as significant and long-term Hg sinks. Therefore, the use of Hg as an Anthropocene marker must be considered cautiously in coastal systems that act as Hg sinks in times when environmental changes were not caused by human activities.
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Affiliation(s)
- Sanny Castro
- Institute of Geosciences, University of Campinas, Campinas, Brazil.
| | | | - Wilson Machado
- Geochemistry Department, Fluminense Federal University, Niterói, Brazil
| | - Everton Valezio
- Institute of Geosciences, University of Campinas, Campinas, Brazil
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48
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Zhou J, Obrist D. Global Mercury Assimilation by Vegetation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14245-14257. [PMID: 34617727 DOI: 10.1021/acs.est.1c03530] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Assimilation of mercury (Hg) by vegetation represents one of the largest global environmental Hg mass fluxes. We estimate Hg assimilation by vegetation globally via a bottom-up scaling approach using tissue Hg concentrations synthesized from a comprehensive database multiplied by respective annual biomass production (NPP). As global annual NPP is close to annual vegetation die-off, Hg mass associated with global NPP approximates the transfer of Hg from plants to soils, which represents an estimate of vegetation-mediated atmospheric deposition. Annual vegetation assimilation of Hg from combined atmospheric and soil uptake is estimated at 3062 ± 607 Mg yr-1, which is composed of 2491 ± 551 Mg yr-1 from aboveground tissue uptake and 571 ± 253 Mg yr-1 from root uptake. Assimilation of atmospheric Hg amounts to 2422 ± 483 Mg yr-1 when considering aboveground tissues only. Atmospheric assimilation increases to 2705 ± 504 Mg yr-1 when considering that root Hg may be partially derived from prior foliar uptake and transported internally to roots. Estimated atmospheric Hg assimilation by vegetation is 54-137% larger than the current model and litterfall estimates, largely because of the inclusion of lichens, mosses, and woody tissues in deposition and all global biomes. Belowground, about 50% of root Hg was taken up from soils with currently unknown ecological and biogeochemical consequences.
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Affiliation(s)
- Jun Zhou
- Department of Environmental, Earth, and Atmospheric Sciences, University of Massachusetts, Lowell, Massachusetts 01854, United States
| | - Daniel Obrist
- Department of Environmental, Earth, and Atmospheric Sciences, University of Massachusetts, Lowell, Massachusetts 01854, United States
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49
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Yuan W, Wang X, Lin CJ, Sommar JO, Wang B, Lu Z, Feng X. Quantification of Atmospheric Mercury Deposition to and Legacy Re-emission from a Subtropical Forest Floor by Mercury Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:12352-12361. [PMID: 34449213 DOI: 10.1021/acs.est.1c02744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Air-soil exchange of elemental mercury vapor (Hg0) is an important component in the budget of the global mercury cycle. However, its mechanistic detail is poorly understood. In this study, stable Hg isotopes in air, soil, and pore gases are characterized in a subtropical evergreen forest to understand the mechanical features of the air-soil Hg0 exchange. Strong HgII reduction in soil releases Hg0 to pore gas during spring-autumn but diminishes in winter, limiting the evasion in cold seasons. Δ199Hg in air modified by the Hg0 efflux during flux chamber measurement exhibit seasonality, from -0.33 ± 0.05‰ in summer to -0.08 ± 0.05‰ in winter. The observed seasonal variation is caused by a strong pore-gas driven soil efflux caused by photoreduction in summer, which weakens significantly in winter. The annual Hg0 gross deposition is 42 ± 33 μg m-2 yr-1, and the corresponding Hg0 evasion from the forest floor is 50 ± 41 μg m-2 yr-1. The results of this study, although still with uncertainty, offer new insights into the complexity of the air-surface exchange of Hg0 over the forest land for model implementation in future global assessments.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xun Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Jonas Olof Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Bo Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyun Lu
- National Forest Ecosystem Research Station at Ailaoshan, Jingdong, Yunnan 676209, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China
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50
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Rodríguez Martin JA, Gutiérrez C, Escuer M, Martín-Dacal M, Ramos-Miras JJ, Roca-Perez L, Boluda R, Nanos N. Trends in soil mercury stock associated with pollution sources on a Mediterranean island (Majorca, Spain). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 283:117397. [PMID: 34030063 DOI: 10.1016/j.envpol.2021.117397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 04/12/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
Hg is a global concern given its adverse effects on human health, food security and the environment, and it requiring actions to identify major local Hg sources and to evaluate pollution. Our study provides the first assessment of Hg stock trends on the entire Majorca surface, identifying major Hg sources by studying the spatiotemporal soil Hg variation at two successive times (2006 and 2016-17). The Hg soil concentration ranged from 14 to 258 μg kg-1 (mean 52 μg kg-1). Higher concentrations (over 100 μg kg-1) were found in two areas: (i) close to the Alcudia coal-fired power plant; (ii) in the city of La Palma. During the 11-year, the total Hg stock in Majorcan soil increased from 432.96 tons to 493.18 tones (14% increase). Based on a block kriging analysis, soil Hg enrichment due to power plant emissions was clearly detectable on a local scale (i.e. a shorter distance than 18 km from the power plant). Nonetheless, a significant island-wide Hg increase due to diffuse pollution was reported. This result could be extrapolated to other popular tourist destinations in the Mediterranean islands where tourism has increased in recent decades In short, more than 60 tons of Hg have accumulated on Majorca island in 11 years.
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Affiliation(s)
- José Antonio Rodríguez Martin
- Department of Environment, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), ES, 28040, Madrid, Spain.
| | - Carmen Gutiérrez
- Instituto de Ciencias Agrarias, ICA- CSIC, Serrano, 114bis, 28006, Madrid, Spain.
| | - Miguel Escuer
- Instituto de Ciencias Agrarias, ICA- CSIC, Serrano, 114bis, 28006, Madrid, Spain.
| | - Marina Martín-Dacal
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Parque Científico y Tecnológico, UPM Campus de Montegancedo, 28223, Madrid, Spain.
| | - José Joaquín Ramos-Miras
- Dpto. Didáctica Ciencias Sociales y Experimentales, Universidad de Córdoba, Avda. San Alberto Magno S/n, Córdoba, 14071, Spain.
| | - Luis Roca-Perez
- Dept. Biologia Vegetal, Facultat de Farmàcia, Universitat de València, Av. Vicent Andrés I Estellés S/n, 46100, Burjassot, Valencia, Spain.
| | - Rafael Boluda
- Dept. Biologia Vegetal, Facultat de Farmàcia, Universitat de València, Av. Vicent Andrés I Estellés S/n, 46100, Burjassot, Valencia, Spain.
| | - Nikos Nanos
- School of Forestry and Natural Environment, Aristotle University of Thessaloniki, 59 Moschounti Str., 55134, Foinikas-Thessaloniki, Greece.
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