1
|
Aslam MW, Meng B, Ali W, Abrar MM, Abdelhafiz MA, Feng X. Low mercury risks in paddy soils across the Pakistan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 943:173879. [PMID: 38857798 DOI: 10.1016/j.scitotenv.2024.173879] [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: 03/28/2024] [Revised: 05/31/2024] [Accepted: 06/07/2024] [Indexed: 06/12/2024]
Abstract
Mercury (Hg) is a globally distributed heavy metal. Here, we study Hg concentration and isotopic composition to understand the status of Hg pollution and its sources in Pakistan's paddy soil. The collected paddy soils (n = 500) across the country have an average THg concentration of 22.30 ± 21.74 ng/g. This low mean concentration suggests Hg pollution in Pakistan was not as severe as previously thought. Meanwhile, samples collected near brick kilns and industrial areas were significantly higher in THg than others, suggesting the influence of Hg emitted from point sources in certain areas. Soil physicochemical properties showed typical characteristic of mineral soils due to the study area's arid to semi-arid climate. Hg stable isotopes analysis, depicted mean Δ199Hg of -0.05 ± 0.12‰ and mean δ202Hg -0.45 ± 0.35‰, respectively, for contaminated sites, depicting Hg was primarily sourced from coal combustion by local anthropogenic sources. While uncontaminated sites show mean Δ199Hg of 0.15 ± 0.08‰, mean Δ200Hg of 0.06 ± 0.07‰ and mean δ202Hg of -0.32 ± 0.28‰, implying long-range transboundry Hg transport through wet Hg(II) deposition as a dominant Hg source. This study fills a significant knowledge gap regarding the Hg pollution status in Pakistan and suggests that the Hg risk in Pakistan paddies is generally low.
Collapse
Affiliation(s)
- Muhammad Wajahat Aslam
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China.
| | - Waqar Ali
- Department of Ecological Sciences and Engineering, College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
| | - Muhammad Mohsin Abrar
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, 510225 Guangzhou, China; Engineering and Technology Research Center for Agricultural Land Pollution and Integrated Prevention, Guangzhou, China
| | - Mahmoud A Abdelhafiz
- Geology Department, Faculty of Science, Al-Azhar University, Assiut 71524, Egypt
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| |
Collapse
|
2
|
Sun S, Ma M, Guo J, He X, Yin X, Sun T, Zhang Q, Kang S. Westerlies-driven transboundary transport of atmospheric mercury to the north-central Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 932:173135. [PMID: 38734088 DOI: 10.1016/j.scitotenv.2024.173135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
The transboundary mercury (Hg) pollution has caused adverse effects on fragile ecosystems of the Tibetan Plateau (TP). Yet, knowledge of transport paths and source regions of atmospheric Hg on the inland TP remains poor. Continuous measurements of atmospheric total gaseous mercury (TGM) were conducted in the central TP (Tanggula station, 5100 m a.s.l., June-October). Atmospheric TGM level at Tanggula station (1.90 ± 0.30 ng m-3) was higher than the background level in the Northern Hemisphere. The identified high-potential source regions of atmospheric TGM were primarily located in the northern South Asia region. TGM concentrations were lower during the Indian summer monsoon (ISM)-dominant period (1.81 ± 0.25 ng m-3) than those of the westerly-receding period (2.18 ± 0.40 ng m-3) and westerly-intensifying period (1.91 ± 0.26 ng m-3), contrary to the seasonal pattern in southern TP. The distinct TGM minima during the ISM-dominant period indicated lesser importance of ISM-transported Hg to Tanggula station located in the northern boundary of ISM intrusion, compared to stations in proximity to South and Southeast Asia source regions. Instead, from the ISM-dominant period to the westerly-intensifying period, TGM concentrations showed an increasing trend as westerlies intensified, indicating the key role of westerlies in transboundary transport of atmospheric Hg to the inland TP.
Collapse
Affiliation(s)
- Shiwei Sun
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China
| | - Ming Ma
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Junming Guo
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China
| | - Xiaobo He
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Tanggula Cryosphere and Environment Observation Station, State Key Laboratory of Cryospheric Science, Lanzhou 730000, China
| | - Xiufeng Yin
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China
| | - Tao Sun
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Qianggong Zhang
- State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, CAS, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| |
Collapse
|
3
|
Luo K, Yuan W, Lu Z, Xiong Z, Lin CJ, Wang X, Feng X. Unveiling the Sources and Transfer of Mercury in Forest Bird Food Chains Using Techniques of Vivo-Nest Video Recording and Stable Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6007-6018. [PMID: 38513264 DOI: 10.1021/acs.est.3c10972] [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: 03/23/2024]
Abstract
Knowledge gaps in mercury (Hg) biomagnification in forest birds, especially in the most species-rich tropical and subtropical forests, limit our understanding of the ecological risks of Hg deposition to forest birds. This study aimed to quantify Hg bioaccumulation and transfer in the food chains of forest birds in a subtropical montane forest using a bird diet recorded by video and stable Hg isotope signals of biological and environmental samples. Results show that inorganic mercury (IHg) does not biomagnify along food chains, whereas methylmercury (MeHg) has trophic magnification factors of 7.4-8.1 for the basal resource-invertebrate-bird food chain. The video observations and MeHg mass balance model suggest that Niltava (Niltava sundara) nestlings ingest 78% of their MeHg from forest floor invertebrates, while Flycatcher (Eumyias thalassinus) nestlings ingest 59% from emergent aquatic invertebrates (which fly onto the canopy) and 40% from canopy invertebrates. The diet of Niltava nestlings contains 40% more MeHg than that of Flycatcher nestlings, resulting in a 60% higher MeHg concentration in their feather. Hg isotopic model shows that atmospheric Hg0 is the main Hg source in the forest bird food chains and contributes >68% in most organisms. However, three categories of canopy invertebrates receive ∼50% Hg from atmospheric Hg2+. Overall, we highlight the ecological risk of MeHg exposure for understory insectivorous birds caused by atmospheric Hg0 deposition and methylation on the forest floor.
Collapse
Affiliation(s)
- Kang Luo
- 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
| | - Zichun Xiong
- Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, Yunnan 676200, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Xun Wang
- 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
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
4
|
Yang YH, Kim MS, Park J, Kwon SY. Atmospheric mercury uptake and accumulation in forests dependent on climatic factors. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2024; 26:519-529. [PMID: 38344926 DOI: 10.1039/d3em00454f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The environmental and climatic factors dictating atmospheric mercury (Hg) uptake by foliage and accumulation within the forest floor are evaluated across six mountain sites, South Korea, using Hg concentration and Hg stable isotope analyses. The isotope ratios of total gaseous Hg (TGM) at six mountains are explained by local anthropogenic Hg emission influence and partly by mountain elevation and wind speed. The extent to which TGM is taken up by foliage is not dependent on the site-specific TGM concentration, but by the local wind speed, which facilitates TGM passage through dense deciduous canopies in the Korean forests. This is depicted by the significant positive relationship between wind speed and foliage Hg concentration (r2 = 0.92, p < 0.05) and the magnitude of δ202Hg shift from TGM to foliage (r2 = 0.37, p > 0.05), associated with TGM uptake and oxidation by foliar tissues. The litter and topsoil Hg concentrations and isotope ratios reveal relationships with a wide range of factors, revealing lower Hg level and greater isotopic fractionation at sites with low elevation, high wind speed, and high mean warmest temperature. We attribute this phenomenon to active TGM re-emission from the forest floor at sites with high wind speed and high temperature, caused by turnover of labile organic matter and decomposition. In contrast to prior studies, we observe no significant effect of precipitation on forest Hg accumulation but precipitation appears to reduce foliage-level Hg uptake by scavenging atmospheric Hg species available for stomata uptake. The results of this study would enable better prediction of future atmospheric and forest Hg influence under climate change.
Collapse
Affiliation(s)
- Yo Han Yang
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea.
| | - Min-Seob Kim
- Environmental Measurement & Analysis Center, National Institute of Environmental Research, 42 Hwangyong-Ro, Seo-Gu, Incheon 22689, South Korea
| | - Jaeseon Park
- Environmental Measurement & Analysis Center, National Institute of Environmental Research, 42 Hwangyong-Ro, Seo-Gu, Incheon 22689, South Korea
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea.
| |
Collapse
|
5
|
Janiga M, Janiga M, Pitoňáková T. Differential accumulation of metals in the lacustrine and fluvial Alpine bullheads (Cottus poecilopus) and recovery of fish from metal contamination after a flash flood. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:17387-17400. [PMID: 38340297 PMCID: PMC10894169 DOI: 10.1007/s11356-024-32288-z] [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: 07/19/2023] [Accepted: 01/27/2024] [Indexed: 02/12/2024]
Abstract
The spatiotemporal distribution and transport of mercury, zinc, molybdenum, rubidium, and strontium from alpine terrestrial ecosystems to alpine lake and mountain stream populations of Cottus poecilopus were investigated. Metals were measured for 66 wild fish collected from different lakes and Javorinka stream across. Mercury was measured in the pectoral fins, other elements in the skull. Bullheads contained more metals in the alpine lakes than in the mountain stream. In particular, mercury and zinc concentrations in lake bullheads were 6 and 2.5 times higher, respectively, than those of stream-dwelling fish. New data were generated on metal bioaccumulation in fish of understudied West Carpathian alpine lake environments. In July 2018, a major flood occurred in the area of the Javorinka. Already then, the mercury content in bullheads increased significantly. Bioaccumulation of mercury in fish occurred very quickly after the flood and was also significant in the following 2019. Then, the concentrations of mercury quickly decreased up to 70% in 2021-2022. Average concentrations of molybdenum and rubidium in bullheads in the stream rapidly declined in the year following the flood disturbance, but within less than 2 years, the metal levels stabilized at about the same level as in 2017 prior the flood. Strontium concentrations in fish dropped rapidly immediately after the flood, increased in the following years, and dropped again after 4 years, suggesting that many more factors are influencing strontium bioaccumulation in fish that are comparable in magnitude to the flood. The most serious warning seems to be the absence of biogenic zinc. The average concentration in the Alpine bullheads population in the stream has declined by 70% in less than 5 years and is steadily declining. An important result of this study is the demonstration that disturbance by a single factor (heavy rainfall and flooding) has a clear and timely effect on average metal concentrations in the fish population.
Collapse
Affiliation(s)
- Marián Janiga
- Institute of High Mountain Biology, University of Žilina, Tatranská Javorina 7, 059 56, Žilina, Tatranská Javorina, Slovakia
| | - Martin Janiga
- Institute of High Mountain Biology, University of Žilina, Tatranská Javorina 7, 059 56, Žilina, Tatranská Javorina, Slovakia
- Faculty of Humanities and Natural Scienes, University of Presov, Presov, Slovakia
| | - Tatiana Pitoňáková
- Institute of High Mountain Biology, University of Žilina, Tatranská Javorina 7, 059 56, Žilina, Tatranská Javorina, Slovakia.
| |
Collapse
|
6
|
Kim YG, Kwon SY, Washburn SJ, Hong Y, Han SH, Lee M, Park JH. Environmental forensics approach to source investigation in a mercury contaminated river: Insights from mercury stable isotopes. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132559. [PMID: 37729710 DOI: 10.1016/j.jhazmat.2023.132559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/10/2023] [Accepted: 09/12/2023] [Indexed: 09/22/2023]
Abstract
Environmental forensics approach was applied to assess the efficacy of mercury (Hg) stable isotopes for source screening and decision-making in the Hyeongsan River, South Korea. Four Hg contamination scenarios were identified- atmospheric Hg emissions from a steel manufacturing industry, upstream riverine Hg transport, and industrial Hg releases and historical landfill collapse from Gumu Creek. The absence of significant Hg isotope difference between the Hyeongsan River sediments (δ202Hg; -0.46 ± 0.17‰, Δ199Hg; -0.04 ± 0.06‰) and the Gumu Creek sediment (δ202Hg; -0.39 ± 0.26‰, Δ199Hg; -0.04 ± 0.03‰) confirm that Hg source is originated from Gumu Creek. The heterogeneous Hg distribution throughout Gumu Creek and statistically similar Hg isotope ratios between Gumu Creek and solid waste cores from the landfill suggests that the landfill collapse is the dominant source to the Hyeongsan-Gumu system. Present Hg releases is also possible given the elevated and matching Δ199Hg between some riverine sediments and wastewater sampled from the landfill. The ternary mixing model estimates that the landfill collapse and wastewater releases contribute 61 ± 25 % and 22 ± 11 %, and the regional background, reflecting terrestrial runoff using deep sediment cores, explain 17 ± 24 % of Hg to the riverine sediment. We suggest that Hg isotopes can be used for routine source screening in areas where Hg sources are unknown.
Collapse
Affiliation(s)
- Young Gwang Kim
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea; Institute for Convergence Research and Education in Advanced Technology, Yonsei University, 85 Songdogwahak-Ro, Yeonsu-Gu, Incheon 21983, South Korea.
| | - Spencer J Washburn
- Geosyntec Consultants, Inc., 100 Washington Ave. S, Suite 1590, Minneapolis, MN 55401, USA
| | - Yongseok Hong
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-Ro, Sejong City 30019, South Korea
| | - Seung Hee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-Ro, Buk-Gu, Gwangju 61005, South Korea
| | - Mikyung Lee
- Water Environmental Engineering Research Division, National Institute of Environmental Research, 42 Hwangyeong-Ro, Seo-Gu, Incheon 22689, South Korea
| | - Ji Hyoung Park
- Water Environmental Engineering Research Division, National Institute of Environmental Research, 42 Hwangyeong-Ro, Seo-Gu, Incheon 22689, South Korea
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Gačnik J, Gustin MS. Tree rings as historical archives of atmospheric mercury: A critical review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165562. [PMID: 37454835 DOI: 10.1016/j.scitotenv.2023.165562] [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] [Received: 05/19/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Historical concentrations of atmospheric mercury (Hg) are uncertain, as monitoring only began a few decades ago. Tree rings can serve as historical archives of Hg, providing centennial trends. The vast majority of tree-ring Hg studies have been published in the last decade, demonstrating the growing use of tree rings for Hg dendrochemistry. Thus, there is a need for a systematic review on current knowledge of tree rings as archives of atmospheric Hg. In this review, the predominant pathways of Hg uptake to tree rings are discussed, including the initial Hg uptake from the surrounding environment, fixation, and subsequent translocation. Foliar uptake of Hg was found to be the most important uptake route for Hg in tree rings, the root and bark route being negligible. Our summary of the suitability of different tree species indicates that radial translocation is the biggest limiting factor for Hg dendrochemistry, shifting and blurring historical Hg trends. Based on the review findings, Picea (spruce) and Larix (larch) are the most promising genera for Hg dendrochemistry. Additionally, the use of tree-ring Hg archives in combination with other co-located archives, namely lake sediments, peat, and ice, is suggested as it enhances the viability of observed tree-ring historical Hg trends. Finally, we propose future directions and recommendations for research using tree-ring Hg, including sampling protocols, experimental designs, and tree selection.
Collapse
Affiliation(s)
- Jan Gačnik
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, USA.
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, USA
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
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.
Collapse
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.
| |
Collapse
|
12
|
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).
Collapse
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.
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Zeng S, Li X, Yang L, Wang D. Understanding heavy metal distribution in timberline vegetations: A case from the Gongga Mountain, eastern Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162523. [PMID: 36870262 DOI: 10.1016/j.scitotenv.2023.162523] [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: 01/14/2023] [Revised: 02/24/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
To quantify impacts of vegetation and topographic factors on heavy metal accumulation in montane forests, we assessed the spatial distribution and determined the sources of mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu) and zinc (Zn) in timberline forests of Gongga Mountain. Our results show that vegetation type has little impact on the soil Hg, Cd and Pb concentrations. The soil concentrations of Cr, Cu and Zn are controlled by litter return, moss and lichen biomass, and canopy interception, with the highest concentrations in shrub forest. In contrast to other forests, the soil Hg pool in coniferous forest is significantly high due to the elevated Hg concentration and greater biomass production in litter. However, the soil pool sizes of Cd, Cr, Cu and Zn show a distinct increase along the elevation, which are attributed to the elevated heavy metal inputs from litter and moss, as well as the greater cloud water-induced atmospheric heavy metal depositions. The highest Hg concentrations of the aboveground parts of plant are in the foliage and bark, while the concentrations of Cd, Pb, Cr, Cu and Zn in the branch and bark are the highest. The decreased biomass density leads to a downward trend in the total vegetation pool sizes of Hg, Cd, Pb, Cr, Cu and Zn by 0.4-4.4 times with increasing elevation. The statistical analysis finally suggests that Hg, Cd and Pb mainly originate from anthropogenic atmospheric deposition, whereas Cr, Cu and Zn are mainly from natural sources. Our results highlight the importance of vegetation types and terrain conditions on distribution patterns of heavy metal in alpine forests.
Collapse
Affiliation(s)
- Shufang Zeng
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xianming Li
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Luhan Yang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China; Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, Southwest University, Chongqing 400716, China.
| |
Collapse
|
15
|
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.
Collapse
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
| |
Collapse
|
16
|
Liu N, Cai X, Jia L, Wang X, Yuan W, Lin CJ, Wang D, Feng X. Quantifying Mercury Distribution and Source Contribution in Surface Soil of Qinghai-Tibetan Plateau Using Mercury Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5903-5912. [PMID: 36976750 DOI: 10.1021/acs.est.2c09610] [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: 06/18/2023]
Abstract
Long-range transport and atmospheric deposition of gaseous mercury (Hg0) result in significant accumulation of Hg in the Qinghai-Tibetan Plateau (QTP). However, there are significant knowledge gaps in understanding the spatial distribution and source contribution of Hg in the surface soil of the QTP and factors influencing Hg accumulation. In this study, we comprehensively investigated Hg concentrations and isotopic signatures in the QTP to address these knowledge gaps. Results show that the average Hg concentration in the surface soil ranks as follows: forest (53.9 ± 36.9 ng g-1) > meadow (30.7 ± 14.3 ng g-1) > steppe (24.5 ± 16.1 ng g-1) > shrub (21.0 ± 11.6 ng g-1). Hg isotopic mass mixing and structural equation models demonstrate that vegetation-mediated atmospheric Hg0 deposition dominates the Hg source in the surface soil, with an average contribution of 62 ± 12% in forests, followed by 51 ± 10% in shrub, 50 ± 13% in steppe, and 45 ± 11% in meadow. Additionally, geogenic sources contribute 28-37% of surface soil Hg accumulation, and atmospheric Hg2+ inputs contribute 10-18% among the four types of biomes. The Hg pool in 0-10 cm surface soil over the QTP is estimated as 8200 ± 3292 Mg. Global warming, permafrost degradation, and anthropogenic influences have likely perturbed Hg accumulation in the soil of QTP.
Collapse
Affiliation(s)
- 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
| | - Xinyuan Cai
- 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
| | - Longyu Jia
- 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
| | - 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
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| |
Collapse
|
17
|
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: 4] [Impact Index Per Article: 4.0] [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.
Collapse
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.
| |
Collapse
|
18
|
Qin X, Dong X, Tao Z, Wei R, Zhang H, Guo Q. Tracing the transboundary transport of atmospheric Particulate Bound Mercury driven by the East Asian monsoon. JOURNAL OF HAZARDOUS MATERIALS 2023; 446:130678. [PMID: 36608578 DOI: 10.1016/j.jhazmat.2022.130678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/13/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
Taking Beijing-Tianjin-Hebei (BTH) with severe atmospheric mercury (Hg) and PM2.5 pollution as a typical region, this study clarified the characteristics and transboundary transport of atmospheric Particulate Bound Mercury (PBM2.5) affected by the East Asian monsoon. Five sampling sites were conducted in rural, suburban, urban, industrial, and coastal areas of BTH from northwest to southeast along the East Asian monsoon direction. PBM2.5 showed increasing concentrations from northwest to southeast and negative δ202Hg values, indicating significant contributions from anthropogenic sources. However, the mean Δ199Hg values of PBM2.5 at the five sites were significantly positive, probably triggered by the photoreduction of Hg(II) during long-range transport driven by the East Asian monsoon. Apart from local anthropogenic emissions as the primary sources, the transboundary transport of PBM2.5, driven by west and northwest air masses originating in Central Asia and Russia, contributed significantly to the PBM2.5 pollution of BTH. Moreover, these air masses reaching BTH would carry elevated PBM2.5 concentrations further transported to the ocean by the East Asian monsoon. In contrast, the southeast air masses transported from the ocean by the East Asian monsoon in summer diluted inland PBM2.5 pollution. This study provides insight into the atmospheric Hg circulation affected by the East Asian monsoon.
Collapse
Affiliation(s)
- Xuechao Qin
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Health, Ethics and Society, Care and Public Health Research Institute, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht 6229 HA, the Netherlands
| | - Xinyuan Dong
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhenghua Tao
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rongfei Wei
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Hua Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Qingjun Guo
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China.
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
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.
Collapse
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
| |
Collapse
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
Zeng S, Wang X, Yuan W, Luo J, Wang D. Mercury accumulation and dynamics in montane forests along an elevation gradient in Southwest China. J Environ Sci (China) 2022; 119:1-10. [PMID: 35934454 DOI: 10.1016/j.jes.2021.10.015] [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: 07/11/2021] [Revised: 10/06/2021] [Accepted: 10/11/2021] [Indexed: 06/15/2023]
Abstract
Understanding atmospheric mercury (Hg) accumulation in remote montane forests is critical to assess the Hg ecological risk to wildlife and human health. To quantify impacts of vegetation, climatic and topographic factors on Hg accumulation in montane forests, we assessed the Hg distribution and stoichiometric relations among Hg, carbon (C), and nitrogen (N) in four forest types along the elevation of Mt. Gongga. Our results show that Hg concentration in plant tissues follows the descending order of litter > leaf, bark > root > branch > bole wood, indicating the importance of atmospheric Hg uptake by foliage for Hg accumulation in plants. The foliar Hg/C (from 237.0 ± 171.4 to 56.8 ± 27.7 µg/kg) and Hg/N (from 7.5 ± 3.9 to 2.5 ± 1.2 mg/kg) both decrease along the elevation. These elevation gradients are caused by the heterogeneity of vegetation uptake of atmospheric Hg and the variation of atmospheric Hg° concentrations at different altitudes. Organic soil Hg accumulation is controlled by forest types, topographic and climatic factors, with the highest concentration in the mixed forest (244.9 ± 55.7 µg/kg) and the lowest value in the alpine forest (151.9 ± 44.5 µg/kg). Further analysis suggests that soil Hg is positively correlated to C (r2 = 0.66) and N (r2 = 0.57), and Hg/C and Hg/N both increase with the soil depth. These stoichiometric relations highlight the combined effects from environmental and climatic factors which mediating legacy Hg accumulation and selective Hg absorption during processes of organic soil mineralization.
Collapse
Affiliation(s)
- Shufang Zeng
- 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
| | - Ji Luo
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, Chengdu 610041, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China.
| |
Collapse
|
23
|
Chen C, Huang JH, Meusburger K, Li K, Fu X, Rinklebe J, Alewell C, Feng X. The interplay between atmospheric deposition and soil dynamics of mercury in Swiss and Chinese boreal forests: A comparison study. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 307:119483. [PMID: 35595001 DOI: 10.1016/j.envpol.2022.119483] [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: 02/20/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
Taking advantage of the different histories of Hg deposition in Davos Seehornwald in E-Switzerland and Changbai Mountain in NE-China, the influence of atmospheric deposition on Hg soil dynamics in forest soil profiles was investigated. Today, Hg fluxes in bulk precipitation were similar, and soil profiles were generally sinks for atmospherically deposited Hg at both sites. Noticeably, a net release of 2.07 μg Hg m-2 yr-1 from the Bs horizon (Podzol) in Seehornwald was highlighted, where Hg concentration (up to 73.9 μg kg-1) and soil storage (100 mg m-3) peaked. Sequential extraction revealed that organic matter and crystalline Fe and Al hydr (oxide)-associated Hg decreased in the E horizon but increased in the Bs horizon as compared to the Ah horizon, demonstrating the coupling of Hg dynamics with the podzolisation process and accumulation of legacy Hg deposited last century in the Bs horizon. The mor humus in Seehornwald allowed Hg enrichment in the forest floor (182-269 μg kg-1). In Changbai Mountain, the Hg concentrations in the Cambisol surface layer with mull humus were markedly lower (<148 μg kg-1), but with much higher Hg soil storage (54-120 mg m-3) than in the Seehornwald forest floor (18-27 mg m-3). Thus, the vertical distribution pattern of Hg was influenced by humus form and soil type. The concentrations of Hg in soil porewater in Seehornwald (3.4-101 ng L-1) and in runoff of Changbai Mountain (1.26-5.62 ng L-1) were all low. Moreover, the pools of readily extractable Hg in the soils at both sites were all <2% of total Hg. Therefore, the potential of Hg release from the forest soil profile to the adjacent aquatic environment is currently low at both sites.
Collapse
Affiliation(s)
- Chaoyue Chen
- 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
| | - Jen-How Huang
- Environmental Geosciences, University of Basel, 4056, Basel, Switzerland
| | - Katrin Meusburger
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
| | - Kai Li
- 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
| | - Xuewu Fu
- 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
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285, Wuppertal, Germany; International Research Centre of Nanotechnology for Himalayan Sustainability (IRCNHS), Shoolini University, Solan, 173212, Himachal Pradesh, India
| | - Christine Alewell
- Environmental Geosciences, University of Basel, 4056, Basel, Switzerland
| | - 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.
| |
Collapse
|
24
|
Ma H, Cheng H, Guo F, Zhang L, Tang S, Yang Z, Peng M. Distribution of mercury in foliage, litter and soil profiles in forests of the Qinling Mountains, China. ENVIRONMENTAL RESEARCH 2022; 211:113017. [PMID: 35217011 DOI: 10.1016/j.envres.2022.113017] [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: 11/25/2021] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Forest ecosystems have been confirmed to be a sink of the global mercury (Hg) in the biogeochemical cycle. However, few studies have investigated the distribution of Hg in forest ecosystems on a regional scale in China. This work aimed to investigate the concentrations, distribution and influential factors of Hg in the Qinling Mountains forests in central China. Foliage, litter and soil profile samples were collected at 24 sampling sites across the Qinling Mountains forests. The results of the present study showed that the concentrations of Hg in foliage, litter, organic soils and mineral soils were maintained at relatively low levels compared with those in subtropical forests of Southwest China. The average Hg concentrations followed the order litter (74 ± 34 ng g-1) > organic soil (71 ± 37 ng g-1) > mineral soil (34 ± 21 ng g-1) > foliage (31 ± 15 ng g-1). Mercury in foliage showed no obvious spatial pattern, likely due to differences in tree species and ages across the sampling sites. Higher concentrations of Hg in litter were observed on the southern slope (low altitude), while the distribution of Hg in organic soils was the opposite. Both the tree species and environmental parameters (altitude, temperature and precipitation) controlled the Hg concentrations in litter by regulating the decomposition rate of the litter. There were significantly positive correlations between the Hg concentrations and soil organic carbon, nitrogen and sulfur in all soil layers, indicating that organic matter has a high geochemical affinity for Hg in soils. Because of the lower turnover rate and the higher accumulation of organic matter in high altitude and low temperature areas, Hg loss from biogeochemical cycling processes was effectively reduced. The spatial distribution of Hg in forests soil can be shaped by the distribution of organic matter at the regional scale.
Collapse
Affiliation(s)
- Honghong Ma
- Institute of Geophysical & Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, 065000, China; Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone, Chinese Academy Geological Sciences, Langfang, 065000, China; Geochemical Research Center of Soil Quality, China Geological Survey, Langfang, 065000, China
| | - Hangxin Cheng
- Institute of Geophysical & Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, 065000, China; Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone, Chinese Academy Geological Sciences, Langfang, 065000, China; Geochemical Research Center of Soil Quality, China Geological Survey, Langfang, 065000, China.
| | - Fei Guo
- Institute of Geophysical & Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, 065000, China; Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone, Chinese Academy Geological Sciences, Langfang, 065000, China; Geochemical Research Center of Soil Quality, China Geological Survey, Langfang, 065000, China
| | - Li Zhang
- Institute of Geophysical & Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, 065000, China; Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone, Chinese Academy Geological Sciences, Langfang, 065000, China; Geochemical Research Center of Soil Quality, China Geological Survey, Langfang, 065000, China
| | - Shiqi Tang
- Institute of Geophysical & Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, 065000, China; Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone, Chinese Academy Geological Sciences, Langfang, 065000, China; Geochemical Research Center of Soil Quality, China Geological Survey, Langfang, 065000, China
| | - Zheng Yang
- Institute of Geophysical & Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, 065000, China; Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone, Chinese Academy Geological Sciences, Langfang, 065000, China; Geochemical Research Center of Soil Quality, China Geological Survey, Langfang, 065000, China
| | - Min Peng
- Institute of Geophysical & Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, 065000, China; Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone, Chinese Academy Geological Sciences, Langfang, 065000, China; Geochemical Research Center of Soil Quality, China Geological Survey, Langfang, 065000, China
| |
Collapse
|
25
|
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.
Collapse
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.
| |
Collapse
|
26
|
Huang S, Jiang R, Song Q, Zhao Y, Lv S, Zhang Y, Huo Y, Chen Y. The Hg behaviors in mangrove ecosystems revealed by Hg stable isotopes: a case study of Maowei mangrove. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:25349-25359. [PMID: 34843054 DOI: 10.1007/s11356-021-17744-4] [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: 08/13/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
As one of the most productive marine ecosystems in the tropics and subtropics, mangroves are an important part of the global mercury (Hg) cycling. The environmental processes and effects of Hg in mangroves are complex and affect human Hg exposure, and it is crucial to understand Hg behaviors in the mangrove ecosystem. However, clarifying Hg behaviors in the mangrove ecosystem remains difficult because of an insufficient understanding of the dominant pathways. In this study, measurements of mercury (Hg) concentration and isotope ratios in sediment and plant tissues from a mangrove wetland were used to investigate Hg isotope fractionation in mangrove plants and sediments. Spatial patterns in Hg concentration and isotope signatures indicate that Hg re-emission in the sediment was suppressed by mangrove plants. The ratio of Δ199Hg/Δ201Hg was 0.93 for all sediments, indicating that Hg mass-independent fractionation in the mangrove ecosystem was primarily affected by photoreduction, while the ratios of Δ199Hg/Δ201Hg and Δ199Hg/δ202Hg for plant tissues suggested that natural organic matter reduction of Hg(II) was occurred in the plants. The distinct positive Δ199Hg values found in mangrove plants were supposed to be the results of the unique physiological characteristics of mangroves. The exterior Hg sources from atmosphere and seawater emphasize the role of mangrove ecosystems in the global Hg biogeochemistry. Our study highlights the distinct Hg isotope signatures in the mangrove from that in forests and indicates unique Hg behaviors in the mangrove ecosystem.
Collapse
Affiliation(s)
- Shuyuan Huang
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| | - Ronggen Jiang
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
| | - Qingyong Song
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| | - Yuhan Zhao
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Supeng Lv
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
| | - Yuanbiao Zhang
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China.
| | - Yunlong Huo
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
| | - Yaojin Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| |
Collapse
|
27
|
Chen X, Zheng L, Sun R, Liu S, Li C, Chen Y, Xu Y. Mercury in sediment reflecting the intensive coal mining activities: Evidence from stable mercury isotopes and Bayesian mixing model analysis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 234:113392. [PMID: 35272196 DOI: 10.1016/j.ecoenv.2022.113392] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Severe environmental issues are caused by long-term coal mining activities; however, the process of mercury (Hg) response in mining subsidence area sediments (MSAS) is still unclear, and direct evidence showing the relationship between Hg accumulation mechanism in sediments and mining activities is lacking. In this study, the characteristics of total mercury (THg) content in MSAS were investigated. Moreover, Hg isotopes were obtained to determine the main sources and environmental process of mercury in MSAS, and a MixSIAR mixing model was first used to estimate the potential Hg sources. The THg content ranged from 27.5 to 113.9 ng/g, with a mean of 65.8 ± 29.4 ng/g, exceeding the local soil background value (19.7 ng/g). The Hg in MSAS was affected by clay and organic matter. The Δ199Hg and Δ201Hg in the sediments varied from - 0.05-0.05‰ (mean: -0.01 ± 0.03‰) and - 0.07-0.01‰ (mean: -0.02 ± 0.03‰), respectively, with the fitting results suggesting that a photochemical reaction occurred in some of the Hg in the sediments prior to deposition. The results of the MixSIAR mixing model revealed that the Hg in MSAS was mainly derived from gangue, soil erosion, coal, fly ash, and feed, and their corresponding percentage contribution was 51.5 ± 9.6%, 23.8 ± 13.1%, 13.9 ± 7.9%, 8.1 ± 5.4%, and 3.1 ± 1.4%, respectively. Hg isotopes can be used to trace the transport and transformation of environmental pollutants, and this may provide an important reference for the assessment and prevention of Hg pollution in typical areas such as coal mining and coal-fired.
Collapse
Affiliation(s)
- Xing Chen
- 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.
| | - Ruoyu Sun
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Sikui Liu
- 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
| | - Yongchun Chen
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan 232001, Anhui, China
| | - Yanfei Xu
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan 232001, Anhui, China
| |
Collapse
|
28
|
Drummond LDO, Meire RO, Braga C, Rezende CED, Malm O, Cerqueira R. Trophic position, altitudinal distribution, and water dependence as determining factors for mercury concentrations in tropical montane anurans. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151356. [PMID: 34728193 DOI: 10.1016/j.scitotenv.2021.151356] [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: 09/16/2021] [Revised: 10/21/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Mercury (Hg) is a widespread and toxic contaminant with potential for long-range atmospheric transport. Previous work has shown that temperate and subtropical montane ecosystems have great potential for deposition of this element. However, little information exists regarding Hg dynamics in tropical mountains. In present study, we evaluated the influence of altitudinal distribution, size, trophic position, and degree of water dependence on Hg concentration in amphibians. For this purpose, we determined the mercury concentration in topsoil and amphibian samples collected at 32 points distributed between 327 and 2181 m above sea level in Serra dos Órgãos, a mountainous complex located in southeastern Brazil. We analyzed the concentration of mercury in whole body samples of 200 individuals of 30 amphibian species. Trophic position of the specimens was estimated by nitrogen stable isotope (δ15N) composition in muscle tissues. We observed a positive relationship between elevation and Hg concentration in topsoil samples from rainforest sites. However, in samples from nebular forest and campos de altitude (highland grasslands) sites, the concentration of Hg was considered lower than expected by the trend in rainforest points, indicating that the vegetation structure plays an important role in the deposition of atmospheric mercury. Mercury concentration in amphibians varies according to the functional characteristics of the species and the environment in which the individual is inserted. Elevation, trophic level and water dependence explained at least some degree of variation in Hg concentration in amphibian tissues. Thus, this community-level analysis suggests that mountainous areas in the tropical region, as recorded for temperate and subtropical mountains, act as regional convergence and deposition sites for atmospheric mercury.
Collapse
Affiliation(s)
- Leandro de Oliveira Drummond
- Laboratório de Ciências Ambientais, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro, RJ CEP: 28013-602, Brazil; Laboratório de Vertebrados, Departamento de Ecologia, Universidade Federal do Rio de Janeiro, C.P. 68020, CEP: 21941-902 Rio de Janeiro, RJ, Brazil.
| | - Rodrigo Ornellas Meire
- Laboratório de Radioisótopos Eduardo Penna-Franca, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CEP: 21941-900 Rio de Janeiro, RJ, Brazil.
| | - Caryne Braga
- Laboratório de Ciências Ambientais, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro, RJ CEP: 28013-602, Brazil.
| | - Carlos Eduardo de Rezende
- Laboratório de Ciências Ambientais, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro, RJ CEP: 28013-602, Brazil.
| | - Olaf Malm
- Laboratório de Radioisótopos Eduardo Penna-Franca, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CEP: 21941-900 Rio de Janeiro, RJ, Brazil.
| | - Rui Cerqueira
- Laboratório de Vertebrados, Departamento de Ecologia, Universidade Federal do Rio de Janeiro, C.P. 68020, CEP: 21941-902 Rio de Janeiro, RJ, Brazil.
| |
Collapse
|
29
|
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.
Collapse
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
| |
Collapse
|
30
|
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.
Collapse
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.
| |
Collapse
|
31
|
Jung S, Kwon SY, Hong Y, Yin R, Motta LC. Isotope investigation of mercury sources in a creek impacted by multiple anthropogenic activities. CHEMOSPHERE 2021; 282:130947. [PMID: 34119733 DOI: 10.1016/j.chemosphere.2021.130947] [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: 02/19/2021] [Revised: 05/09/2021] [Accepted: 05/18/2021] [Indexed: 06/12/2023]
Abstract
To investigate mercury (Hg) sources responsible for contamination at Gumu Creek in South Korea, Hg concentration (THg) and Hg isotope ratios were measured in the soil and sediment of Gumu Creek and the samples from a hazardous waste landfill (HWL). The THg ranged between 0.29-327 mg kg-1 and 9.5-414 mg kg-1 in the soil and sediment, respectively, reflecting heterogeneous distribution and elevated levels across the entire Gumu Creek. Without the soil with the lowest THg (0.30 ± 0.01 mg kg-1, n = 3), the δ202Hg (-0.83 to -0.18‰) and Δ199Hg (-0.24 to 0.01‰) of the sediment and soil of Gumu Creek were within the ranges of the HWL samples (δ202Hg; -1.29 to -0.38‰, Δ199Hg; -0.31 to 0.01‰). The comparison with the literature reporting sediment Hg isotope ratios impacted by various anthropogenic Hg sources revealed a presence of diverse Hg sources at Gumu Creek, including commercial liquid Hg, phenyl-Hg, and fly ash, consistent with the types of waste deposited within the HWL. Using commercial liquid Hg, fly ash, and the soil with the lowest THg as end-members, the ternary mixing model yielded 25-88% and 12-57% contributions from commercial liquid Hg and fly ash to the Gumu Creek sediment, respectively. The results of our study suggest that Hg isotope ratios are an effective tool for screening potential Hg sources at sites where the distribution of Hg is heterogeneous and multiple anthropogenic activities exist.
Collapse
Affiliation(s)
- Saebom Jung
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea; Institute for Convergence Research and Education in Advanced Technology, Yonsei University, 85 Songdogwahak-Ro, Yeonsu-Gu, Incheon, 21983, South Korea.
| | - Yongseok Hong
- Department of Environmental Engineering, Korea University, 2511 Sejong-Ro, Sejong City, 30019, South Korea
| | - Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China
| | - Laura C Motta
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea
| |
Collapse
|
32
|
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.
Collapse
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
| |
Collapse
|
33
|
Kurz AY, Blum JD, Johnson MW, Nadelhoffer K, Zak DR. Isotopic composition of mercury deposited via snow into mid-latitude ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147252. [PMID: 34088049 DOI: 10.1016/j.scitotenv.2021.147252] [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: 02/01/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
Atmospheric deposition of mercury (Hg) to terrestrial and aquatic ecosystems has significant implications for human and animal exposure. Measurements of Hg isotopic composition can be utilized to trace sources of Hg, but outside of the Arctic there has been little Hg isotopic characterization of snow. To better understand deposition pathways at mid-latitudes, five time series of snowfall were collected at two sites (Dexter and Pellston, Michigan, USA) to investigate the Hg isotopic composition of snowfall, how it changes after deposition, and how it compares to rain. The Hg isotopic composition of a subset of fresh snow samples revealed the influence of reactive surface uptake of atmospheric Hg(0). The first time series collected at Dexter occurred during a polar vortex, demonstrating Hg isotopic fractionation dynamics similar to those in Arctic snow, with increasingly negative Δ199Hg as snow aged with exposure to sunlight. All other time series revealed an increase in Δ199Hg as snow aged, with values reaching up to 3.5‰. This characterization of Hg isotopes in snow suggests a strong influence of oxidants and binding ligands in snow that may mediate Hg isotope fractionation. Additionally, isotopic characterization of Hg in snow deposited to natural ecosystems at mid-latitudes allows for better understanding of atmospheric mercury sources that are deposited to lakes and forests and that may become available for methylation and transfer to food webs.
Collapse
Affiliation(s)
- Aaron Y Kurz
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marcus W Johnson
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Knute Nadelhoffer
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Donald R Zak
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; School of the Environment and Sustainability, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
34
|
Wang X, Yuan W, Lin CJ, Wu F, Feng X. Stable mercury isotopes stored in Masson Pinus tree rings as atmospheric mercury archives. JOURNAL OF HAZARDOUS MATERIALS 2021; 415:125678. [PMID: 33765566 DOI: 10.1016/j.jhazmat.2021.125678] [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: 02/04/2021] [Revised: 02/28/2021] [Accepted: 03/14/2021] [Indexed: 06/12/2023]
Abstract
The accuracy of mercury (Hg) dendrochemistry has been questioned because significant knowledge gaps exist in understanding the Hg translocation and mobility in tree-ring. In this study, we evaluated Hg concentrations and isotopic profiles in the tree-ring at a Hg artisanal mining site and a control site with the documented local Hg production inventory. Results show that the Hg concentration accumulated in tree-ring fails to reconstruct the temporal trend of Hg production due to confounded tree physiological and environmental factors, specifically, the radial translocation and tree age effects occurring during the fast-growing period. The temporal profiles of δ202Hg exhibit pronounced tree-specific variabilities due to the complexity of Hg isotopic mass dependent fractionation during atmospheric Hg uptake and translocation in vegetation. The Hg odd-MIF (mass independent fractionation) profiles in tree-ring can reconstruct a decadal-scale temporal trend of the atmospheric Hg0 pollution level, and also be used as a tracer to distinguish the emission source shifts of atmospheric Hg0. However, the radial translocation would result in uncertainties at the higher resolution because of the mixing of odd-MIF signatures with active rings. Caution should be taken and additional supporting evidence collected from independent methods should be used for verifying the tree-ring records.
Collapse
Affiliation(s)
- Xun Wang
- 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.
| | - 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 77710, USA; Department of Civil and Environmental Engineering, Lamar University, Beaumont 77710, USA
| | - Fei Wu
- Key Laboratory for Information System of Mountainous Area and Protection of Ecological Environment of Guizhou Province, Guizhou Normal University, Guiyang 550001, 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.
| |
Collapse
|
35
|
Ballabio C, Jiskra M, Osterwalder S, Borrelli P, Montanarella L, Panagos P. A spatial assessment of mercury content in the European Union topsoil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 769:144755. [PMID: 33736262 PMCID: PMC8024745 DOI: 10.1016/j.scitotenv.2020.144755] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 05/29/2023]
Abstract
Mapping of surface soil Hg concentrations, a priority pollutant, at continental scale is important in order to identify hotspots of soil Hg distribution (e.g. mining or industrial pollution) and identify factors that influence soil Hg concentrations (e.g. climate, soil properties, vegetation). Here we present soil Hg concentrations from the LUCAS topsoil (0-20 cm) survey including 21,591 samples from 26 European Union countries (one sample every ~200 km2). Deep Neural Network (DNN) learning models were used to map the European soil Hg distribution. DNN estimated a median Hg concentration of 38.3 μg kg-1 (2.6 to 84.7 μg kg-1) excluding contaminated sites. At continental scale, we found that soil Hg concentrations increased with latitude from south to north and with altitude. A GLMM revealed a correlation (R2 = 0.35) of soil Hg concentrations with vegetation activity, normalized difference vegetation index (NDVI), and soil organic carbon content. This observation corroborates the importance of atmospheric Hg0 uptake by plants and the build-up of the soil Hg pool by litterfall over continental scales. The correlation of Hg concentrations with NDVI was amplified by higher soil organic matter content, known to stabilize Hg in soils through thiol bonds. We find a statistically significant relation between soil Hg levels and coal use in large power plants, proving that emissions from power plants are associated with higher mercury deposition in their proximity. In total 209 hotspots were identified, defined as the top percentile in Hg concentration (>422 μg kg-1). 87 sites (42% of all hotspots) were associated with known mining areas. The sources of the other hotspots could not be identified and may relate to unmined geogenic Hg or industrial pollution. The mapping effort in the framework of LUCAS can serve as a starting point to guide local and regional authorities in identifying Hg contamination hotspots in soils.
Collapse
Affiliation(s)
| | - Martin Jiskra
- Environmental Geosciences, University of Basel, Basel, Switzerland.
| | - Stefan Osterwalder
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP, IGE, Grenoble, France.
| | - Pasquale Borrelli
- Università degli Studi di Pavia, Dipartimento di Scienze della Terra e dell'Ambiente, Pavia, Italy.
| | | | - Panos Panagos
- European Commission, Joint Research Centre (JRC), Ispra, Italy.
| |
Collapse
|
36
|
Lu Z, Yuan W, Luo K, Wang X. Litterfall mercury reduction on a subtropical evergreen broadleaf forest floor revealed by multi-element isotopes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115867. [PMID: 33160734 DOI: 10.1016/j.envpol.2020.115867] [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: 08/24/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Litterfall mercury (Hg) deposition is the dominant source of soil Hg in forests. Identifying reduction processes and tracking the fate of legacy Hg on forest floor are challenging tasks. Interplays between isotopes of carbon (C) and nitrogen (N) may shed some lights on Hg biogeochemical processes because their biogeochemical cycling closely links with organic matters. Isotope measurements at the evergreen broadleaf forest floor at Mt. Ailao (Mountain Ailao) display that δ202Hg and Δ199Hg both significantly correlate with δ13C and δ15N in soil profiles. Data analysis results show that microbial reduction is the dominant process for the distinct δ202Hg shift (up to ∼1.0‰) between Oi and 0-10 cm surface mineral soil, and dark abiotic organic matter reduction is the main cause for the Δ199Hg shift (∼-0.18‰). Higher N in foliage leads to greater Hg concentration, and Hg0 re-emission via microbial reduction on forest floor is likely linked to N release and immobilization on forest floor. We thus suggest that the enhanced N deposition in global forest ecosystems can potentially influence Hg uptake by vegetation and litter Hg sequestration on forest floor.
Collapse
Affiliation(s)
- Zhiyun Lu
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Xishuangbanna, Yunnan, 666303, China; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, Yunnan, 676200, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Kang Luo
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Xishuangbanna, Yunnan, 666303, China; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, Yunnan, 676200, China
| | - Xun Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China.
| |
Collapse
|
37
|
Cao F, Meng M, Shan B, Sun R. Source apportionment of mercury in surface soils near the Wuda coal fire area in Inner Mongolia, China. CHEMOSPHERE 2021; 263:128348. [PMID: 33297273 DOI: 10.1016/j.chemosphere.2020.128348] [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: 07/08/2020] [Revised: 09/07/2020] [Accepted: 09/12/2020] [Indexed: 06/12/2023]
Abstract
The Wuda coalfield, Inner Mongolia, China, has been suffering from serious coal fire disaster for more than half a century. In the past decade, the central and local governments have carried out many fire-fighting projects to put out the coal fires, but coal fires still sporadically occur in the coalfield. Previous studies showed that coal fires could release large amounts of mercury (Hg) into the environment. Meanwhile, the rapid industrial development in recent years in Wuda area has also discharged a certain amount of Hg. Identification and quantification of the Hg emitted from coal fires and industrial sources is critical to formulate appropriate environmental policies. This study determined Hg isotope compositions in different types of coals from Wuda coal fire area and surface soils with different distances to the coal fire area, with an aim of anchoring the potential Hg sources in soils. The results showed that the coals had moderately negative δ202Hg (-2.02∼-1.21‰) and slightly negative Δ199Hg (-0.14-0.00‰), while the soils generally had more positive δ202Hg (-1.97∼-0.26‰) and Δ199Hg (-0.07-0.04‰) with distinct isotope ranges among different sampling sites. According to characteristic Hg isotope compositions of different sources, we concluded that the Hg in Wuda soils mainly sourced from cement plants and coal fires, and coal fires were still an important Hg contamination source in Wuda area.
Collapse
Affiliation(s)
- Fei Cao
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Mei Meng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China.
| | - Bing Shan
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Ruoyu Sun
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China.
| |
Collapse
|
38
|
Gu J, Pang Q, Ding J, Yin R, Yang Y, Zhang Y. The driving factors of mercury storage in the Tibetan grassland soils underlain by permafrost. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:115079. [PMID: 32806461 DOI: 10.1016/j.envpol.2020.115079] [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: 03/01/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 06/11/2023]
Abstract
Soils, especially permafrost in the Arctic and the Tibetan Plateau, are one of the largest reservoirs of mercury (Hg) in the global environment. The Hg concentration in the grassland soils over the Tibetan Plateau and its driving factors have been less studied. This study analyzes soil total mercury (STHg) concentrations and its vertical distribution in grassland soil samples collected from the Tibetan Plateau. We adopt a nested-grid high-resolution GEOS-Chem model to simulate atmospheric Hg deposition. The relationship between STHg and soil organic carbon (SOC), as well as atmospheric deposition, are explored. Our results show that the STHg concentrations in the Tibetan Plateau are 19.8 ± 12.2 ng/g. The concentrations are higher in the south and lower in the north in the Tibetan Plateau, consistent with the previous results. Our model shows that the average deposition flux of Hg is 3.3 μg m-2 yr-1, with 57% contributed by dry deposition of elemental mercury (Hg0), followed by dry (19%) and wet (24%) deposition of divalent mercury. We calculate the Hg to carbon ratio (RHg:C) as 5.6 ± 6.5 μg Hg/g C, and the estimated STHg is 86.6 ± 101.2 Gg in alpine grasslands in the Tibetan Plateau. We find a positive relationship between STHg and SOC in the Tibetan Plateau (r2 = 0.36) and a similar positive relationship between STHg and atmospheric total Hg deposition (r2 = 0.24). A multiple linear regression involving both variables better model the observed STHg (r2 = 0.42). We conclude that SOC and atmospheric deposition influence STHg simultaneously in this region. The data provides information to quantify the size of the soil Hg pool in the Tibetan Plateau further, which has important implications for the Hg cycles in the permafrost regions as well as on the global scale.
Collapse
Affiliation(s)
- Jing Gu
- School of Atmospheric Sciences, Nanjing University, Nanjing, 210023, China
| | - Qiaotong Pang
- School of Atmospheric Sciences, Nanjing University, Nanjing, 210023, China
| | - Jinzhi Ding
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China
| | - Runsheng Yin
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environment Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yanxu Zhang
- School of Atmospheric Sciences, Nanjing University, Nanjing, 210023, China.
| |
Collapse
|
39
|
Kurz AY, Blum JD, Gratz LE, Jaffe DA. Contrasting Controls on the Diel Isotopic Variation of Hg 0 at Two High Elevation Sites in the Western United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10502-10513. [PMID: 32786593 DOI: 10.1021/acs.est.0c01918] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The atmosphere is a significant global reservoir for mercury (Hg) and its isotopic characterization is important to understand sources, distribution, and deposition of Hg to the Earth's surface. To better understand Hg isotope variability in the remote background atmosphere, we collected continuous 12-h Hg0 samples for 1 week from two high elevation sites, Camp Davis, Wyoming (valley), and Mount Bachelor, Oregon (mountaintop). The samples collected at Camp Davis displayed strong diel variation in δ202Hg values of Hg0, but not in Δ199Hg or Δ200Hg values. We attribute this pattern to nightly atmospheric inversions trapping Hg in the valley and the subsequent nighttime uptake of Hg by vegetation, which depletes Hg from the atmosphere. At Mount Bachelor, the samples displayed diel variation in both δ202Hg and Δ199Hg, but not Δ200Hg. We attribute this pattern to differences in the vertical distribution of Hg in the atmosphere as Mount Bachelor received free tropospheric air masses on certain nights during the sampling period. Near the end of the sampling period at Mount Bachelor, the observed diel pattern dissipated due to the influence of a nearby forest fire. The processes governing the Hg isotopic fractionation differ across sites depending on mixing, topography, and vegetation cover.
Collapse
Affiliation(s)
- Aaron Y Kurz
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N University Avenue, Ann Arbor, Michigan 48109, United States
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N University Avenue, Ann Arbor, Michigan 48109, United States
| | - Lynne E Gratz
- Environmental Studies Program, Colorado College, Colorado Springs, Colorado 80903, United States
| | - Daniel A Jaffe
- School of Science, Technology, Engineering & Mathematics, University of Washington Bothell, Bothell, Washington 98011, United States
| |
Collapse
|
40
|
Yuan W, Wang X, Lin CJ, Wu C, Zhang L, Wang B, Sommar J, Lu Z, Feng X. Stable Mercury Isotope Transition during Postdepositional Decomposition of Biomass in a Forest Ecosystem over Five Centuries. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8739-8749. [PMID: 32551609 DOI: 10.1021/acs.est.0c00950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Organic soil is an important transient reservoir of mercury (Hg) in terrestrial ecosystems, but the fate of deposited Hg in organic forest soil is poorly understood. To understand the dynamic changes of deposited Hg on forest floor, the composition of stable Hg and carbon (C) isotopes in decomposing litters and organic soil layer was measured to construct the 500 year history of postdepositional Hg transformation in a subtropical evergreen broad-leaf forest in Southwest China. Using the observational data and a multiprocess isotope model, the contributions of microbial reduction, photoreduction, and dark reduction mediated by organic matter to the isotopic transition were estimated. Microbial reduction and photoreduction play a dominant role in the initial litter decomposition during first 2 years. Dark redox reactions mediated by organic matter become the predominant process in the subsequent 420 years. After that, the values of Hg mass dependent fractionation (MDF), mass independent fractionation (MIF), and Δ199Hg/Δ201Hg ratio do not change significantly, indicating sequestration and immobilization of Hg in soil. The linear correlations between the isotopic signatures of Hg and C suggest that postdepositional transformation of Hg is closely linked to the fate of natural organic matter (NOM). Our findings are consistent with the abiotic dark reduction driven by nuclear volume effect reported in boreal and tropical forests. We recommend that the dark reduction process be incorporated in future model assessment of the global Hg biogeochemical cycle.
Collapse
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
| | - Chuansheng Wu
- Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Anhui 236037, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario M3H 5T4, Canada
| | - 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
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Zhiyun Lu
- National Forest Ecosystem Research Station at Ailaoshan, 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
| |
Collapse
|
41
|
Wang X, Yuan W, Lin CJ, Luo J, Wang F, Feng X, Fu X, Liu C. Underestimated Sink of Atmospheric Mercury in a Deglaciated Forest Chronosequence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8083-8093. [PMID: 32510932 DOI: 10.1021/acs.est.0c01667] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Mercury (Hg) deposition through litterfall has been regarded as the main input of gaseous elemental mercury (Hg0) into forest ecosystems. We hypothesize that earlier studies largely underestimated this sink because the contribution of Hg0 uptake by moss and the downward transport to wood and throughfall is overlooked. To test the hypothesis, we investigated the Hg fluxes contributed via litterfall and throughfall, Hg pool sizes in moss covers and woody biomass as well as their isotopic signatures in a glacier-to-forest succession ecosystem of the Southeast Tibetan Plateau. Results show that Hg0 depositional uptake and pool sizes stored in moss and woody biomass increase rapidly with the time after glacier retreat. Using the flux data as input to a Hg isotopic mixing model, Hg deposition through litterfall accounts for 27-85% of the total accumulation rate of Hg0 in organic soils of glacial retreat over 20-90 years, revealing the presence of additional sources of Hg0 input. Atmospheric Hg0 accounts for 76 ± 24% in ground moss, 86 ± 15% in tree moss, 62-92% in above ground woody biomass (branch-bark-stem), and 44-83% in roots. The downward decreasing gradient of atmospheric Hg0 fractions from the above ground woody biomass to roots suggests a foliage-to-root Hg transport in vegetation after uptake. Additionally, 34-82% of atmospheric Hg0 in throughfall further amplifies the accumulation of Hg0 from atmospheric sources. We conclude that woody biomass, moss, and throughfall represent important Hg0 sinks in forest ecosystems. These previously unaccounted for sink terms significantly increase the previously estimated atmospheric Hg0 sink via litterfall.
Collapse
Affiliation(s)
- Xun Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
- 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
- Department of Civil and Environmental Engineering, Lamar University, Beaumont, Texas 77710, United States
| | - Ji Luo
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, Chengdu 610041, China
| | - Feiyue Wang
- Centre for Earth Observation Science, and Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - 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
| | - Xuewu Fu
- 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
| | - Chen Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| |
Collapse
|
42
|
Sommar J, Osterwalder S, Zhu W. Recent advances in understanding and measurement of Hg in the environment: Surface-atmosphere exchange of gaseous elemental mercury (Hg 0). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 721:137648. [PMID: 32182462 DOI: 10.1016/j.scitotenv.2020.137648] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 05/26/2023]
Abstract
The atmosphere is the major transport pathway for distribution of mercury (Hg) globally. Gaseous elemental mercury (GEM, hereafter Hg0) is the predominant form in both anthropogenic and natural emissions. Evaluation of the efficacy of reductions in emissions set by the UN's Minamata Convention (UN-MC) is critically dependent on the knowledge of the dynamics of the global Hg cycle. Of these dynamics including e.g. red-ox reactions, methylation-demethylation and dry-wet deposition, poorly constrained atmosphere-surface Hg0 fluxes especially limit predictability of the timescales of its global biogeochemical cycle. This review focuses on Hg0 flux field observational studies, namely the theory, applications, strengths, and limitations of the various experimental methodologies applied to gauge the exchange flux and decipher active sub-processes. We present an in-depth review, a comprehensive literature synthesis, and methodological and instrumentation advances for terrestrial and marine Hg0 flux studies in recent years. In particular, we outline the theory of a wide range of measurement techniques and detail the operational protocols. Today, the most frequently used measurement techniques to determine the net Hg0 flux (>95% of the published flux data) are dynamic flux chambers for small-scale and micrometeorological approaches for large-scale measurements. Furthermore, top-down approaches based on Hg0 concentration measurements have been applied as tools to better constrain Hg emissions as an independent way to e.g. challenge emission inventories. This review is an up-dated, thoroughly revised edition of Sommar et al. 2013 (DOI: 10.1080/10643389.2012.671733). To the tabulation of >100 cited flux studies 1988-2009 given in the former publication, we have here listed corresponding studies published during the last decade with a few exceptions (2008-2019). During that decade, Hg stable isotope ratios of samples involved in atmosphere-terrestrial interaction is at hand and provide in combination with concentration and/or flux measurements novel constraints to quantitatively and qualitatively assess the bi-directional Hg0 flux. Recent efforts in the development of relaxed eddy accumulation and eddy covariance Hg0 flux methods bear the potential to facilitate long-term, ecosystem-scale flux measurements to reduce the prevailing large uncertainties in Hg0 flux estimates. Standardization of methods for Hg0 flux measurements is crucial to investigate how land-use change and how climate warming impact ecosystem-specific Hg0 sink-source characteristics and to validate frequently applied model parameterizations describing the regional and global scale Hg cycle.
Collapse
Affiliation(s)
- Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.
| | - Stefan Osterwalder
- Institut des Géosciences de l'Environnement, Université Grenoble Alpes, CNRS, IRD, Grenoble INP, Grenoble, France
| | - Wei Zhu
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| |
Collapse
|
43
|
Huang J, Kang S, Yin R, Lin M, Guo J, Ram K, Li C, Sharma C, Tripathee L, Sun S, Wang F. Decoupling Natural and Anthropogenic Mercury and Lead Transport from South Asia to the Himalayas. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5429-5436. [PMID: 32242420 DOI: 10.1021/acs.est.0c00429] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) and lead (Pb) accumulation since the Industrial Revolution has been generally observed to increase concurrently in lake sedimentary records around the world. Located downwind during the monsoon season from the rapidly developing South Asia, the Himalayas and the Tibetan Plateau are expected to receive direct anthropogenic Hg and Pb loadings, yet the source, pathway, and effects of such transport remain poorly known due to logistic challenges in accessing this region. When studying the sediment record from Lake Gokyo (4750 m above sea level (a.s.l.)) in the Himalayas, we find remarkably different Hg and Pb accumulation trends over the past 260 years. Although Hg accumulation has continued to increase since the Industrial Revolution, Pb accumulation peaked during that time and has been decreasing since then. Stable isotope analysis reveals that the decoupling trends between these two elements are due to different sources and pathways of Hg and Pb in the region. Both δ202Hg and Δ199Hg have been increasing since the Industrial Revolution, suggesting that anthropogenic Hg emissions from South Asia have been continuously increasing and that the Indian monsoon-driven wet deposition of atmospheric Hg is the dominant pathway for Hg accumulation in the sediments. In contrast, analysis of 206Pb/207Pb and 208Pb/207Pb ratios suggests that Pb accumulation in the sediments originates primarily from natural sources and that the decreasing trend of Pb accumulation is most likely due to a weakening input of atmospheric mineral dust by the westerlies. These decoupling trends highlight the ongoing issue of transboundary Hg transport to the Himalayas and the Tibetan Plateau that are source waters for major freshwater systems in Asia and calls for regional and international collaborations on Hg emission controls in South Asia.
Collapse
Affiliation(s)
- Jie Huang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
| | - Mang Lin
- State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Junming Guo
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Kirpa Ram
- Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi 221005, India
| | - Chaoliu Li
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Chhatra Sharma
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- Central Department of Environmental Science, Tribhuvan University, Kathmandu 6133, Nepal
| | - Lekhendra Tripathee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Shiwei Sun
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Feiyue Wang
- Centre for Earth Observation Science and Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| |
Collapse
|
44
|
Yin R, Pan X, Deng C, Sun G, Kwon SY, Lepak RF, Hurley JP. Consistent trace element distribution and mercury isotopic signature between a shallow buried volcanic-hosted epithermal gold deposit and its weathered horizon. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 259:113954. [PMID: 31952102 DOI: 10.1016/j.envpol.2020.113954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/30/2019] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
Trace elements and Hg isotopic composition were investigated in mineralized rocks, barren rocks, and mineral soils in the Xianfeng prospect, a shallow buried epithermal gold deposit in northeastern China, to understand whether this deposit has left a diagnostic geochemical fingerprint to its weathered horizon. All the rocks and soils display congruent patterns for immobile elements (large ion lithophile elements, high field strength elements, and rare earth elements), which reflect the subduction-related tectonic setting. Both mineralized rocks and soils showed common enrichment of elemental suite As-Ag-Sb-Hg, suggesting that the Xianfeng gold deposit has released these elements into its weathered horizon. Similar mercury isotopic composition was observed between mineralized rocks (δ202Hg: -0.21 ± 0.70‰; Δ199Hg: -0.02 ± 0.12‰; 2SD) and barren rocks (δ202Hg: -0.46 ± 0.48‰; Δ199Hg: 0.00 ± 0.10‰; 2SD), suggesting that mercury in the Xianfeng deposit is mainly derived from the magmatic rocks. Mineralized soils (δ202Hg: -0.44 ± 0.60‰; -0.03 ± 0.14‰; 2SD) and barren soils (δ202Hg: -0.54 ± 0.68‰; Δ199Hg: -0.05 ± 0.14‰; 2SD) displayed congruent Hg isotopic signals to the underlying rocks, suggesting limited Hg isotope fractionation during the release of Hg from ore deposit to soils via weathering. This study reveals evidence of a simple and direct geochemical link between this shallow buried hydrothermal deposit and its weathered horizon, and highlights that the weathering of shallow-buried hydrothermal gold deposits can release a substantial amount of heavy metals (e.g. Hg, As and Sb) to surface soil.
Collapse
Affiliation(s)
- Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Xin Pan
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Changzhou Deng
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Guangyi Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Sae Yun Kwon
- Division of Environmental Science & Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam Gu, Pohang, 37673 South Korea
| | - Ryan F Lepak
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - James P Hurley
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI, 53706, USA
| |
Collapse
|
45
|
Huang S, Jiang R, Song Q, Zhang Y, Huang Q, Su B, Chen Y, Huo Y, Lin H. Study of mercury transport and transformation in mangrove forests using stable mercury isotopes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 704:135928. [PMID: 31838299 DOI: 10.1016/j.scitotenv.2019.135928] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
Mangrove forests are important wetland ecosystems that are a sink for mercury from tides, rivers and precipitation, and can also be sources of mercury production and export. Natural abundance mercury stable isotope ratios have been proven to be a useful tool to investigate mercury behavior in various ecosystems. In this study, mercury isotopic data were collected from seawater, sediments, air, and plant tissues in two mangrove forests in Guangxi and Fujian provinces, China, to study the transport and transformation of mercury in mangrove sediments. The mangroves were primarily subject to mercury inputs from external sources, such as anthropogenic activities, atmospheric deposition, and the surrounding seawater. An isotope mixing model based on mass independent fractionation (MIF) estimated that the mangrove wetland ecosystems accounted for <40% of the mercury in the surrounding seawater. The mercury in plant root tissues was derived mainly from sediments and enriched with light mercury isotopes. The exogenous mercury inputs from the fallen leaves were diluted by seawater, leading to a positive Δ199Hg offset between the fallen leaves and sediments. Unlike river and lake ecosystems, mangrove ecosystems are affected by tidal action, and the δ202Hg and Δ199Hg values of sediments were more negative than that of the surrounding seawater. The isotopic signature differences between these environmental samples were partially due to isotope fractionation driven by various physical and chemical processes (e.g., sorption, photoreduction, deposition, and absorption). These results contribute to a better understanding of the biogeochemical cycling of mercury in mangrove wetland ecosystems.
Collapse
Affiliation(s)
- Shuyuan Huang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
| | - Ronggen Jiang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
| | - Qingyong Song
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China
| | - Yuanbiao Zhang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China.
| | - Qi Huang
- Guangxi Shankou Mangrove Nature Reserve, Beihai 536000, China
| | - Binghuan Su
- Guangxi Shankou Mangrove Nature Reserve, Beihai 536000, China
| | - Yaojin Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China
| | - Yunlong Huo
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
| | - Hui Lin
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
| |
Collapse
|
46
|
Global warming accelerates uptake of atmospheric mercury in regions experiencing glacier retreat. Proc Natl Acad Sci U S A 2020; 117:2049-2055. [PMID: 31932430 DOI: 10.1073/pnas.1906930117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
As global climate continues to warm, melting of glaciers releases a large quantity of mercury (Hg) originally locked in ice into the atmosphere and downstream ecosystems. Here, we show an opposite process that captures atmospheric Hg through glacier-to-vegetation succession. Our study using stable isotope techniques at 3 succession sites on the Tibetan Plateau reveals that evolving vegetation serves as an active "pump" to take up gaseous elemental mercury (Hg0) from the atmosphere. The accelerated uptake enriches the Hg pool size in glacier-retreated areas by a factor of ∼10 compared with the original pool size in the glacier. Through an assessment of Hg source-sink relationship observed in documented glacier-retreated areas in the world (7 sites of tundra/steppe succession and 5 sites of forest succession), we estimate that 400 to 600 Mg of Hg has been accumulated in glacier-retreated areas (5‰ of the global land surface) since the Little Ice Age (∼1850). By 2100, an additional ∼300 Mg of Hg will be sequestered from the atmosphere in glacier-retreated regions globally, which is ∼3 times the total Hg mass loss by meltwater efflux (∼95 Mg) in alpine and subpolar glacier regions. The recapturing of atmospheric Hg by vegetation in glacier-retreated areas is not accounted for in current global Hg models. Similar processes are likely to occur in other regions that experience increased vegetation due to climate or land use changes, which need to be considered in the assessment of global Hg cycling.
Collapse
|
47
|
Huang J, Kang S, Yin R, Guo J, Lepak R, Mika S, Tripathee L, Sun S. Mercury isotopes in frozen soils reveal transboundary atmospheric mercury deposition over the Himalayas and Tibetan Plateau. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 256:113432. [PMID: 31662270 DOI: 10.1016/j.envpol.2019.113432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/12/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
The concentration and isotopic composition of mercury (Hg) were studied in frozen soils along a southwest-northeast transect over the Himalaya-Tibet. Soil total Hg (HgT) concentrations were significantly higher in the southern slopes (72 ± 54 ng g-1, 2SD, n = 21) than those in the northern slopes (43 ± 26 ng g-1, 2SD, n = 10) of Himalaya-Tibet. No significant relationship was observed between HgT concentrations and soil organic carbon (SOC), indicating that the HgT variation was not governed by SOC. Soil from the southern slopes showed significantly negative mean δ202Hg (-0.53 ± 0.50‰, 2SD, n = 21) relative to those from the northern slopes (-0.12 ± 0.40‰, 2SD, n = 10). The δ202Hg values of the southern slopes are more similar to South Asian anthropogenic Hg emissions. A significant correlation between 1/HgT and δ202Hg was observed in all the soil samples, further suggesting a mixing of Hg from South Asian anthropogenic emissions and natural geochemical background. Large ranges of Δ199Hg (-0.45 and 0.24‰) were observed in frozen soils. Most of soil samples displayed negative Δ199Hg values, implying they mainly received Hg from gaseous Hg(0) deposition. A few samples had slightly positive odd-MIF, indicating precipitation-sourced Hg was more prevalent than gaseous Hg(0) in certain areas. The spatial distribution patterns of HgT concentrations and Hg isotopes indicated that Himalaya-Tibet, even its northern part, may have been influenced by transboundary atmospheric Hg pollution from South Asia.
Collapse
Affiliation(s)
- Jie Huang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China
| | - Junming Guo
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Ryan Lepak
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Sillanpää Mika
- Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Mikkeli, FI-50130, Finland
| | - Lekhendra Tripathee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Shiwei Sun
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| |
Collapse
|
48
|
Xue W, Kwon SY, Grasby SE, Sunderland EM, Pan X, Sun R, Zhou T, Yan H, Yin R. Anthropogenic influences on mercury in Chinese soil and sediment revealed by relationships with total organic carbon. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113186. [PMID: 31520907 DOI: 10.1016/j.envpol.2019.113186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 08/24/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
Rapid industrialization has led to high levels of mercury (Hg) releases from anthropogenic sources in China. When deposited to terrestrial ecosystems, Hg has a high affinity for natural organic carbon. This means that Hg concentrations will vary naturally as a function of the total organic carbon (TOC) content of different soils and sediment. Thus, Hg to TOC ratios in topsoil and surface sediment provides a useful normalized tracer of the anthropogenic impact on Hg contamination. We compiled literature-documented Hg and total organic carbon (TOC) data for topsoil (n = 957) and surface sediment (n = 1142) in China. Topsoil samples (n = 100) were also collected in this study to broaden the spatial coverage. We found large differences in Hg:TOC ratios among topsoil from background sites, agricultural and urban areas, and mining sites and surface sediment from fluvial, coastal, and marine environments. Specifically, a significant increase in Hg:TOC ratios occurred between soils from background sites (median: Hg:TOC = 21.1; Inter-Quartile Range (IQR): 9.67 to 40.7) and agricultural areas (median: 34.1; IQR: 22.1 to 58.7), urban areas (median: 62.1 ng g-1; IQR: 34.2 to 154) and mining sites (median: 2780; range: 181 to 43500). Urban and mining sites show the largest increase in Hg:TOC ratios, reflecting elevated anthropogenic Hg inputs in these areas. Fluvial sediment showed higher Hg:TOC ratios (median: 197; IQR: 109 to 389) than coastal (median: 88.3; IQR: 46.8 to 168) and marine sediment (median: 89.7; IQR: 53 to 138), indicating decreased anthropogenic Hg input from rivers to coastal and marine regions. Results of our study suggest Hg:TOC ratios are a useful normalized indicator of the influence of anthropogenic Hg releases on Hg enrichment in topsoil and surface sediment.
Collapse
Affiliation(s)
- Wen Xue
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China; University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Sae Yun Kwon
- Division of Environmental Science & Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam Gu, Pohang, 37673, South Korea
| | - Stephan E Grasby
- Geological Survey of Canada, Natural Resources Canada, Calgary, Alberta, T2L 2A7, Canada
| | - Elsie M Sunderland
- Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA, 02138, United States
| | - Xin Pan
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China; University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Ruiyang Sun
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China; University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Ting Zhou
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China; University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Haiyu Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China.
| | - Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081, Guiyang, China.
| |
Collapse
|
49
|
Wang X, Yuan W, Feng X, Wang D, Luo J. Moss facilitating mercury, lead and cadmium enhanced accumulation in organic soils over glacial erratic at Mt. Gongga, China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 254:112974. [PMID: 31376600 DOI: 10.1016/j.envpol.2019.112974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Moss is usually as an initial colonizer in alpine glacier retreated regions. We hypothesized that moss can significantly facilitate the toxic metals accumulation in alpine ecosystems based on its strong ability of absorption and the role in soil development. Hence, we investigated the trace element pool sizes and enrichment factors, especially for mercury (Hg) by using the Hg isotopic compositions to determine the source contributions in a moss-dominated ecosystem over glacial erratic in Eastern Tibetan Plateau. Results show that Hg, lead (Pb) and cadmium (Cd) are highly enriched in organic soils. Specifically, Cd concentration is 5-20 times higher than the safety limit of the acid soil (pH ≤ 5.5) in China. Atmospheric depositions dominantly contribute to the Pb and Cd sources in organic soils, and followed by the moraine particles influences. The lowering pH in organic soils increasing with glacial retreated time results in the desorption of Cd in organic soils. Atmospheric Hg0 uptake by moss predominantly contributes to the Hg sources in organic soils. The average Pb accumulation rate over last 125-year is about 5.6 ± 1.0 mg m-2 yr-1, and for Cd is 0.4 ± 0.1 mg m-2 yr-1, and for Hg0 is 27.6 ± 3.2 μg m-2 yr-1. These elevated accumulation rates are caused by the high moss biomass and elevated atmospheric Hg, Pb and Cd pollution levels in China and neighbouring regions. Our study indicates that the moss not only as the bioindicator, but also plays an important role in the hazardous metal biogeochemical cycling in alpine regions.
Collapse
Affiliation(s)
- Xun Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; 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
| | - Xinbin Feng
- 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
| | - Ji Luo
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, Chengdu, 610041, China
| |
Collapse
|
50
|
Sun T, Ma M, Wang X, Wang Y, Du H, Xiang Y, Xu Q, Xie Q, Wang D. Mercury transport, transformation and mass balance on a perspective of hydrological processes in a subtropical forest of China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 254:113065. [PMID: 31465902 DOI: 10.1016/j.envpol.2019.113065] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/15/2019] [Accepted: 08/15/2019] [Indexed: 06/10/2023]
Abstract
Forest ecosystem has long been suggested as a vital component in the global mercury (Hg) biogeochemical cycling. However, there remains large uncertainties in understanding total Hg (THg) and methylmercury (MeHg) variations and their controlling factors during the whole hydrological processes in forest ecosystems. Here, we quantified Hg mass flow along hydrological processes of wet deposition, throughfall, stemflow, litter leachate, soil leachate, surface runoff, and stream, and litterfall Hg deposition, and air-forest floor elemental Hg (Hg0) exchange flux to set up a Hg mass balance in a subtropical forest of China. Results showed that THg concentration in stream was lower than that in wet deposition, while an opposite characteristic for MeHg concentration, and both THg and MeHg fluxes of stream were lower than those of wet deposition. Variations of THg and MeHg in throughfall and litter leachate had strong direct and indirect effects on controlling variations of THg and MeHg in surface runoff, soil leachate and stream, respectively. Especially, the net Hg methylation was suggested in the forest canopy and forest floor layers, and significant particulate bound Hg (PBM) filtration was observed in soil layers. The Hg mass balance showed that the litterfall Hg deposition was the main Hg input for forest floor Hg, and the elemental Hg vapor (Hg0) re-emission from forest floor was the dominant Hg output. Overall, we estimated the net THg input flux of 13.8 μg m-2 yr-1 and net MeHg input flux of 0.6 μg m-2 yr-1 within the forest ecosystem. Our results highlighted the important roles of forest canopy and forest floor to shape Hg in output flow, and the forest floor is a distinct sink of MeHg.
Collapse
Affiliation(s)
- Tao Sun
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Ming Ma
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Xun Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Hongxia Du
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Yuping Xiang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Qinqin Xu
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Qing Xie
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing, 400715, China.
| |
Collapse
|