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Wu F, Yang L, Wang X, Yuan W, Lin CJ, Feng X. Mercury Accumulation and Sequestration in a Deglaciated Forest Chronosequence: Insights from Particulate and Mineral-Associated Forms of Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16512-16521. [PMID: 37857302 DOI: 10.1021/acs.est.3c03107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Understanding mercury (Hg) complexation with soil organic matter is important in assessing atmospheric Hg accumulation and sequestration processes in forest ecosystems. Separating soil organic matter into particulate organic matter (POM) and mineral-associated organic matter (MAOM) can help in the understanding of Hg dynamics and cycling due to their very different chemical constituents and associated formation and functioning mechanisms. The concentration of Hg, carbon, and nitrogen contents and isotopic signatures of POM and MAOM in a deglaciated forest chronosequence were determined to construct the processes of Hg accumulation and sequestration. The results show that Hg in POM and MAOM are mainly derived from atmospheric Hg0 deposition. Hg concentration in MAOM is up to 76% higher than that in POM of broadleaf forests and up to 60% higher than that in POM of coniferous forests. Hg accumulation and sequestration in organic soil vary with the vegetation succession. Variations of δ202Hg and Δ199Hg are controlled by source mixing in the broadleaf forest and by Hg sequestration processes in the coniferous forest. Accumulation of atmospheric Hg and subsequent microbial reduction enrich heavier Hg isotopes in MAOM compared to POM due to the specific chemical constituents and nutritional role of MAOM.
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Affiliation(s)
- Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luhan Yang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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Chen P, Wang X, Yuan W, Wang D. Typical heavy metals accumulation, transport and allocation in a deglaciated forest chronosequence, Qinghai-Tibet Plateau. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132162. [PMID: 37517237 DOI: 10.1016/j.jhazmat.2023.132162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/25/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Understanding heavy metals (HMs) accumulation and transportation is the foundation to assess the ecological risks caused by the pollution of HMs in terrestrial ecosystems. There are large knowledge gaps regarding impacts of vegetation succession on shaping the HMs accumulation, transportation and allocation in the remote alpine regions. Herein, we comprehensively investigated the distribution and source contribution of mercury (Hg), cadmium (Cd) and chromium (Cr) along with vegetation succession in a deglaciated forest chronosequence of Qinghai-Tibet Plateau. Results showed that Hg and Cd were highly enriched in organic soils, while Cr concentrations and pool sizes decreased significantly with the vegetation succession. Atmospheric Hg deposition contributed to the dominant Hg sources in topsoil (74 - 87%), whereas moraine weathering was the main source of Cr (73 - 76%). Both moraine (18 - 48%) and atmospheric deposition inputs (52 - 82%) affected Cd accumulation in topsoil. Over the last century, the accumulation rate of Hg and Cd showed the distinctly decreasing trends due to the vegetation leading to the elevated atmospheric depositions at the earlier deglacial sites. The negative accumulation rate of Cr along with the vegetation succession reflected the formation of organic soil diluting the geogenic inputs of Cr.
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Affiliation(s)
- Peijia Chen
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China.
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Ma Y, Wang Q, Su W, Cao G, Fu G, Du W. Potential Sources, Pollution, and Ecological Risk Assessment of Potentially Toxic Elements in Surface Soils on the North-Eastern Margin of the Tibetan Plateau. TOXICS 2022; 10:toxics10070368. [PMID: 35878273 PMCID: PMC9316433 DOI: 10.3390/toxics10070368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 02/04/2023]
Abstract
Due to increased levels of human activity, various pollutants are frequently detected on the Tibetan Plateau, where the environment is extremely fragile and sensitive. Therefore, this study investigated the sources, pollution, and ecological risks of soil potentially toxic elements (PTEs) in different landscape areas within the Qaidam Basin in the northeastern part of the Qinghai−Tibet Plateau. The contents of seven PTEs (Cd, Cu, Pb, Zn, As, Cr, and Ni) in 32 topsoil samples (0−2 cm) were analyzed in different regions of the Qaidam Basin. The concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn were 10.4−29.9 mg/kg, 0.08−4.45 mg/kg, 19−66 mg/kg, 8.2−40 mg/kg, 11.7−30.8 mg/kg, 11.1−31.2 mg/kg, and 32−213 mg/kg, respectively. The correlation between Pb and Cd in unpopulated areas was 0.896 (p < 0.01). The correlations among Pb, Cd, and Zn in agricultural areas, among As, Cd, Cr, and Zn in saline lake areas, and among As, Cd, Cr, Cu, Ni, Pb, and Zn in residential areas were all greater than 0.65 (p < 0.05). The principal component analysis results showed that Pb and Cd in unpopulated areas, Pb, Cd, and Zn in agricultural areas, As, Cd, Cr, Zn, and Pb in saline lake areas, and As, Cd, Cr, Cu, Ni, Pb, and Zn in residential areas were affected by human activities (significant factor >0.70). Based on the geological accumulation index and single-factor pollution index results, the maximum Cd values were found to be 4.93 and 45.88, respectively; Cd was thus the most serious PTE pollutant. The comprehensive pollution index of Nemero showed that moderately and severely polluted areas accounted for 18.89% and 18.46% of the total area, respectively. The results of the potential risk index showed that very strong and strong ecological risk points together accounted for 18.8% of the total points. The spatial variations in PTE pollution and the potential ecological risk index had similar patterns; both increased from the unpopulated areas in the northeastern Qaidam Basin to Golmud city in the south-western Qaidam Basin. These results indicate that human activities negatively impacted the soil ecological environment in the Qaidam Basin during the rapid development of the economy and urbanization and that these negative impacts tended to spread to unpopulated areas. Therefore, it is necessary to emphasize the significant impacts of human activities on environmental quality and formulate preventive measures to reduce PTE pollution in the Qinghai−Tibet Plateau.
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Affiliation(s)
- Yujun Ma
- College of Geographic Science, Qinghai Normal University, Xining 810008, China;
- Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation (Ministry of Education), Qinghai Normal University, Xining 810008, China
- Qinghai Province Key Laboratory of Physical Geography and Environmental Process, Qinghai Normal University, Xining 810008, China
| | - Qiugui Wang
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China;
| | - Weigang Su
- Qinghai Earthquake Agency, Xining 810001, China;
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810016, China
| | - Guangchao Cao
- College of Geographic Science, Qinghai Normal University, Xining 810008, China;
- Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation (Ministry of Education), Qinghai Normal University, Xining 810008, China
- Qinghai Province Key Laboratory of Physical Geography and Environmental Process, Qinghai Normal University, Xining 810008, China
- Correspondence:
| | - Guoyan Fu
- Zhongyuan Institute of Science and Technology, Zhengzhou 450000, China;
| | - Wen Du
- School of Mathematics and Statistics, Qinghai Normal University, Xining 810008, China;
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Gao J, Wang L, Ok YS, Bank MS, Luo J, Wu WM, Hou D. Nanoplastic stimulates metalloid leaching from historically contaminated soil via indirect displacement. WATER RESEARCH 2022; 218:118468. [PMID: 35461104 DOI: 10.1016/j.watres.2022.118468] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/09/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
It is generally believed that the ability of nanoplastics (NPs) to mobilize other contaminants is due to direct adsorption; however, this intuitive belief is questioned in this study when it comes to a historically contaminated soil where mining activities since 1958 have resulted in arsenic (As) and cadmium (Cd) enrichment. Negatively charged polystyrene (PS) NPs were used in this study, which should theoretically stimulate Cd (metal cation) instead of As (negatively charged oxyanion) leaching if direct adsorption accounted for co-transport. Surprisingly, PS NPs enhanced the leaching of As by up to over 5 times (p value < 0.05), but had almost no effect on Cd leaching (p value > 0.05). A novel indirect displacement model was therefore developed to describe the phenomenon of enhanced As leaching. It has been found that negatively charged NPs interacted with As via competition for soil binding sites. Underlying mechanistic insights were further explored via both theoretical calculations with the Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) approach, and direct characterization using Scanning Electron Microscopy (SEM) and Computed X-ray Microtomography (μCT) showing binding sites and flow channels, respectively. The overall results provide new and valuable insights into NP-metal(loid) interactions in the natural soil environment, which can be integrated in future studies regarding the transport and risk assessment of NPs, and toxic metal(loid)s.
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Affiliation(s)
- Jing Gao
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Liuwei Wang
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Yong Sik Ok
- Korea Biochar Research Center, APRU Sustainable Waste Management Program and Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Michael S Bank
- Institute of Marine Research, Bergen, Norway; University of Massachusetts, Amherst, MA 01003, United States
| | - Jian Luo
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0355, United States
| | - Wei-Min Wu
- Department of Civil and Environmental Engineering, William and Cloy Codiga Resource Recovery Center, Center for Sustainable Development & Global Competitiveness, Stanford University, Stanford, CA 94305-4020, United States
| | - Deyi Hou
- School of Environment, Tsinghua University, Beijing 100084, China.
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Liu M, Wei Y, Salam M, Yuan X, Liu B, He Q, Hu X, Li H, He Y. Potassium supplement enhanced cadmium removal in a Microcystis aeruginosa photobioreactor: Evidence from actual and simulated wastewater. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127719. [PMID: 34802826 DOI: 10.1016/j.jhazmat.2021.127719] [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: 09/21/2021] [Revised: 10/22/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
In this study, a Microcystis aeruginosa-based photobioreactor (M. aeruginosa-based PBR) was developed for the removal of cadmium (Cd2+) from diluted actual mine wastewater (DW) and Cd2+-contained simulated wastewater (SW), with a uniform Cd2+ concentration of 0.5 mg/L. For the DW and SW, both K+ -abundant (DWA & SWA) and K+-insufficient (DWB & SWB) treatments were conducted. It was found that continuous supplementation of K+ benefited Cd2+ removal. The Cd2+ removal efficiency in SWA reached 70% during the 41 days of operation, which was 20% higher than that in the SWB. The K+ addition triggered great higher Cd2+ removal efficiency (90%) in the DWA in comparison to the SWA. The Cd2+ assimilation by M. aeruginosa and Cd2+ retention on M. aeruginosa surface were the primary processes involved in the PBR system. The K+ starvation triggered a 45% and 43% loss of M. aeruginosa biomass in the DWA and the DWB, respectively. Hence, the Cd2+ removal efficiency in DWB increased significantly, and this was attributed to the increased abundance of non-living cells and enhanced bioretention of Cd2+. The results revealed that continuous K+ supplementation enhanced the Cd2+ removal efficiency in the M. aeruginosa-based PBR jointly by prompting algal cell growth, Cd2+ assimilation and biosorption, as well as Cd2+ retention on the algal cells.
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Affiliation(s)
- Mengzi Liu
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China
| | - Yanyan Wei
- Cultivation Base of Guangxi Key Laboratory for Agro-Environment and Agro-Products Safety, College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Muhammad Salam
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China
| | - Xiaobing Yuan
- The second Construction Engineering Co., Ltd of the third Bureau of China Construction Co., Ltd., Wuhan 430064, China
| | - Bingsheng Liu
- The second Construction Engineering Co., Ltd of the third Bureau of China Construction Co., Ltd., Wuhan 430064, China
| | - Qiang He
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China
| | - Xuebin Hu
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China
| | - Hong Li
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China; National Centre for International Research of Low-carbon and Green Buildings (Ministry of Science and Technology), Chongqing University, Chongqing, China.
| | - Yixin He
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China.
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Gao T, Liu Y, Xia Y, Zhu JM, Wang Z, Qi M, Liu Y, Ning Z, Wu Q, Xu W, Liu C. Cadmium isotope compositions of Fe-Mn nodules and surrounding soils: Implications for tracing Cd sources. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2021.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Calabrese EJ, Agathokleous E. Accumulator plants and hormesis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 274:116526. [PMID: 33545523 DOI: 10.1016/j.envpol.2021.116526] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 05/17/2023]
Abstract
Accumulation of metals by plants is an important area of investigation in plant ecology and evolution as well as in soil contamination/phytoremediation practices. This paper reports that hormetic-biphasic dose-response relationships were commonly observed for multiple agents (i.e. arsenic, cadmium, chromium, fluoride, lead, and zinc) and 20 species in plant (hyper)accumulator studies. The hormetic stimulation was related to metal accumulation in affected tissues, with the metal stimulation concentration zone unique for each metal, species, tissue, and endpoint studied. However, quantitative features of the hormetic dose response were similar across all (hyper)accumulation studies, with results independent of plant species, endpoints measured, and metal. The dose-dependent stimulatory and inhibitory/toxic plant responses were often associated with the up- and down-regulation of adaptive mechanisms, especially those involving anti-oxidative enzymatic processes. These findings provide a mechanistic framework to account for both the qualitative and quantitative features of the hormetic dose response in plant (hyper)accumulator studies.
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Affiliation(s)
- Edward J Calabrese
- Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, United States.
| | - Evgenios Agathokleous
- School of Applied Meteorology, Nanjing University of Information Science and Technology, Ningliu Rd 219, Nanjing, Jiangsu, 21044, China.
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Yang D, Luo J, Peng P, Li W, Shi W, Jia L, He Y. Dynamics of nitrogen and phosphorus accumulation and their stoichiometry along a chronosequence of forest primary succession in the Hailuogou Glacier retreat area, eastern Tibetan Plateau. PLoS One 2021; 16:e0246433. [PMID: 33529264 PMCID: PMC7853510 DOI: 10.1371/journal.pone.0246433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 01/19/2021] [Indexed: 11/26/2022] Open
Abstract
As the two limiting nutrients for plants in most terrestrial ecosystems, nitrogen (N) and phosphorus (P) are essential for the development of succession forests. Vegetation N:P stoichiometry is a useful tool for detecting nutrient limitation. In the present work, chronosequence analysis was employed to research N and P accumulation dynamics and their stoichiometry during forest primary succession in a glacier retreat area on the Tibetan Plateau. Our results showed that: (1) total ecosystem N and P pools increased from 97 kg hm-2 to 7186 kg hm-2 and 25 kg hm-2 to 487 kg hm-2, respectively, with increasing glacier retreat year; (2) the proportion of the organic soil N pool to total ecosystem N sharply increased with increasing glacier retreat year, but the proportion of the organic soil and the vegetation P pools to the total ecosystem P was equivalent after 125 y of recession; (3) the N:P ratio for tree leaves ranged from 10.1 to 14.3, whereas the N:P ratio for total vegetation decreased form 13.3 to 8.4 and remained constant after 35 y of recession, and the N:P ratio for organic soil increased from 0.2 to 23.1 with increasing glacier retreat. These results suggested that organic soil N increased with increasing years of glacier retreat, which may be the main sink for atmospheric N, whereas increased P accumulation in vegetation after 125 y of recession suggested that much of the soil P was transformed into the biomass P pool. As the N:P ratio for vegetation maintained a low level for 35-125 y of recession, we suggested that N might be the main limiting element for plant growth in the development of this ecosystem.
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Affiliation(s)
- Danli Yang
- College of Earth Sciences, Chengdu University of Technology, Chengdu, Sichuan, China
| | - Ji Luo
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Peihao Peng
- College of Earth Sciences, Chengdu University of Technology, Chengdu, Sichuan, China
| | - Wei Li
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Wenbo Shi
- Tourism and Urban-Rural Planning College, Chengdu University of Technology, Chengdu, Sichuan, China
| | - Longyu Jia
- College of Earth Sciences, Chengdu University of Technology, Chengdu, Sichuan, China
| | - Yongmei He
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan, China
- University of Chinese Academy of Sciences, Beijing, China
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Zhong Q, Zhou Y, Tsang DCW, Liu J, Yang X, Yin M, Wu S, Wang J, Xiao T, Zhang Z. Cadmium isotopes as tracers in environmental studies: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 736:139585. [PMID: 32497890 DOI: 10.1016/j.scitotenv.2020.139585] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Cadmium isotopic compositions in non-contaminated systems and anthropogenic sources of Cd generally have different isotopic signatures. Cadmium isotopes, as a novel tracer, can be useful for fingerprinting the anthropogenic Cd sources, providing a promising source tracing technique in environmental studies. This review presents: (i) analytical techniques for Cd isotopic composition; (ii) isotopic signatures of Cd derived from anthropogenic activities; (iii) isotopic compositions of Cd in the industrial-impacted environmental samples; (iv) cadmium isotopic fractionation induced by geochemical process. Finally, the perspectives of using Cd isotopic compositions in environmental studies are also briefly discussed.
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Affiliation(s)
- Qiaohui Zhong
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510405, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuchen Zhou
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Juan Liu
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Xiao Yang
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Meiling Yin
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Shijun Wu
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510405, China
| | - Jin Wang
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, Guangzhou 510006, China.
| | - Tangfu Xiao
- Institute of Environmental Research at Greater Bay, Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Zhaofeng Zhang
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510405, China
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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.
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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
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