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Liu X, Wang Z, Wang C, Wang B, Cao H, Shan J, Zhang X. Mercury distribution, exposure and risk in Poyang Lake and vicinity, China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123409. [PMID: 38244906 DOI: 10.1016/j.envpol.2024.123409] [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: 09/18/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/22/2024]
Abstract
Mercury (Hg), especially methylmercury (MeHg), which is highly neurotoxic, is a global pollutant that can affect human health because of its accumulation in aquatic products. Poyang Lake, an inland lake in China, has been significantly affected by human activity, yet there is limited understanding of local mercury contamination and potential exposure pathways to humans. In this study, we explored the risks of mercury exposure by sampling sediments, plants, and aquatic organisms in the lake and surrounding areas and analyzing total Hg (THg) and MeHg levels. Sediment sampling was conducted at the main lake, rivers, rice paddies, and fishponds. Two dominant species of plants and 15 species of aquatic organisms were sampled and analyzed. We assessed the characteristics of mercury in sediments using the geo-accumulation index (Igeo), mercury exposure using the biomagnification factor (BMF) and biota sediment accumulation factor (BSAF), and risks using thresholds for adverse effects. The highest THg concentrations (137.04 ± 44.3 ng g-1 dw) were detected in the main lake sediments, whereas the highest MeHg concentrations (0.47 ± 0.6 ng g-1 dw) were detected in fishpond sediments. Mercury accumulation in the main lake sediments could be assessed as contaminated (Igeo > 0: 81.6%). Yellow catfish had the highest mercury concentration (THg 770.69 ± 199.7 ng g-1 dw; MeHg 741.93 ± 168.8 ng g-1 dw). Piscivores were adversely affected by carnivorous fish (50.8%), but all fish concentrations did not exceed the food safety standards recommend by China and the WHO. The mercury exposure results revealed significant Hg biomagnification and enrichment (BMF >1: 94.55%; BSAFmax = 1218). Long-term monitoring of aquatic organisms is warranted.
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Affiliation(s)
- Xu Liu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhangwei Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Chunjie Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bing Wang
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, 100091, China
| | - Huabin Cao
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Jihong Shan
- Wildlife and Plant Protection Center, Jiangxi Provincial Department of Forestry, Nanchang, 330006, China
| | - Xiaoshan Zhang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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2
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Li S, Li Z, Wu M, Zhou Y, Tang W, Zhong H. Mercury transformations in algae, plants, and animals: The occurrence, mechanisms, and gaps. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 911:168690. [PMID: 38000748 DOI: 10.1016/j.scitotenv.2023.168690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023]
Abstract
Mercury (Hg) is a global pollutant showing potent toxicity to living organisms. The transformations of Hg are critical to global Hg cycling and Hg exposure risks, considering Hg mobilities and toxicities vary depending on Hg speciation. Though currently well understood in ambient environments, Hg transformations are inadequately explored in non-microbial organisms. The primary drivers of in vivo Hg transformations are far from clear, and the impacts of these processes on global Hg cycling and Hg associated health risks are not well understood. This hinders a comprehensive understanding of global Hg cycling and the effective mitigation of Hg exposure risks. Here, we focused on Hg transformations in non-microbial organisms, particularly algae, plants, and animals. The process of Hg oxidation/reduction and methylation/demethylation in organisms were reviewed since these processes are the key transformations between the dominant Hg species, i.e., elemental Hg (Hg0), divalent inorganic Hg (IHgII), and methylmercury (MeHg). By summarizing the current knowledge of Hg transformations in organisms, we proposed the potential yet overlooked drivers of these processes, along with potential challenges that hinder a full understanding of in vivo Hg transformations. Knowledge summarized in this review would help achieve a comprehensive understanding of the fate and toxicity of Hg in organisms, providing a basis for predicting Hg cycles and mitigating human exposure.
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Affiliation(s)
- Shouying Li
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Zhuoran Li
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Mengjie Wu
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Yang Zhou
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China
| | - Wenli Tang
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China.
| | - Huan Zhong
- School of the Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China.
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Stinson I, Li HH, Tsui MTK, Ku P, Ulus Y, Cheng Z, Lam HM. Tree foliage as a net accumulator of highly toxic methylmercury. Sci Rep 2024; 14:1757. [PMID: 38242950 PMCID: PMC10799008 DOI: 10.1038/s41598-024-51469-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/05/2024] [Indexed: 01/21/2024] Open
Abstract
Tree canopies are known to elevate atmospheric inputs of both mercury (Hg) and methylmercury (MeHg). While foliar uptake of gaseous Hg is well documented, little is known regarding the temporal dynamics and origins of MeHg in tree foliage, which represents typically less than 1% of total Hg in foliage. In this work, we examined the foliar total Hg and MeHg content by following the growth of five individual trees of American Beech (Fagus grandifolia) for one growing season (April-November, 2017) in North Carolina, USA. We show that similar to other studies foliar Hg content increased almost linearly over time, with daily accumulation rates ranging from 0.123 to 0.161 ng/g/day. However, not all trees showed linear increases of foliar MeHg content along the growing season; we found that 2 out of 5 trees showed elevated foliar MeHg content at the initial phase of the growing season but their MeHg content declined through early summer. However, foliar MeHg content among all 5 trees showed eventual increases through the end of the growing season, proving that foliage is a net accumulator of MeHg while foliar gain of biomass did not "dilute" MeHg content.
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Affiliation(s)
- Idus Stinson
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Han-Han Li
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China.
| | - Martin Tsz-Ki Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA.
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
- Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
| | - Peijia Ku
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Yener Ulus
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
- Department of Environmental Studies, Davidson College, Davidson, NC, 28035, USA
| | - Zhang Cheng
- College of Environment, Sichuan Agricultural University, Chengdu, 611130, China
| | - Hon-Ming Lam
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
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4
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Gustin MS, Dunham-Cheatham SM, Harper JF, Choi WG, Blum JD, Johnson MW. Investigation of the biochemical controls on mercury uptake and mobility in trees. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158101. [PMID: 35987220 DOI: 10.1016/j.scitotenv.2022.158101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/12/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
Atmospheric elemental mercury (Hg(0)) enters plant stomata, becomes oxidized, and is then transferred to annual growth rings providing an archive of air Hg(0) concentrations. To better understand the processes of Hg accumulation and translocation, the foliage of quaking aspen and Austrian pine were exposed to Hg(0), and methylmercury (MeHg) or Me198Hg via roots, in controlled exposures during the summer. Isotopic measurements demonstrated, in a laboratory setting, that the natural mass-dependent fractionation observed was the same as that measured in field studies, with the lighter isotopes being preferentially taken up by the leaves. Hg was measured in plant tissues across seasons. Aspen trees moved Hg into new growth immediately after exposure, resorbed Hg in the fall, and then distributed Hg to new growth tissues in the spring. Austrian pine did not reallocate Hg. Mercury measured in aspen leaf fractions of trees exposed to Hg(0) demonstrated that 85 % of Hg was in the cell wall. It was also found that redox-active molecules, such as H2O2, could potentiate the release of cell wall-bound Hg from aspen leaves, providing a potential mechanism for remobilization. Regardless of the mechanism, the ability of aspen to reallocate Hg to new tissues indicates that Hg distribution in tree rings from aspen do not provide a reliable record of yearly changes in atmospheric Hg(0).
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Affiliation(s)
- Mae Sexauer Gustin
- Department of Natural Resources & Environmental Science, University of Nevada, Reno, 1664 N. Virginia Street, Mail Stop 186, Reno, NV 89557, USA.
| | - Sarrah M Dunham-Cheatham
- Department of Natural Resources & Environmental Science, University of Nevada, Reno, 1664 N. Virginia Street, Mail Stop 186, Reno, NV 89557, USA
| | - Jeffrey F Harper
- Department of Biochemistry & Molecular Biology, University of Nevada, Reno, Reno, NV 89557, USA
| | - Won-Gyu Choi
- Department of Biochemistry & Molecular Biology, University of Nevada, Reno, Reno, NV 89557, USA
| | - Joel D Blum
- Department of Earth and Environmental Science, University of Michigan, 1100 N University, Ann Arbor, MI 48109, USA
| | - Marcus W Johnson
- Department of Earth and Environmental Science, University of Michigan, 1100 N University, Ann Arbor, MI 48109, USA
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Méndez-López M, Gómez-Armesto A, Eimil-Fraga C, Alonso-Vega F, Rodríguez-Soalleiro R, Álvarez-Rodríguez E, Arias-Estévez M, Nóvoa-Muñoz JC. Needle age and precipitation as drivers of Hg accumulation and deposition in coniferous forests from a southwestern European Atlantic region. ENVIRONMENTAL RESEARCH 2022; 215:114223. [PMID: 36063908 DOI: 10.1016/j.envres.2022.114223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/29/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Vegetation and climate are critical in the biogeochemical cycle of Hg in forest ecosystems. The study assesses the influence of needle age and precipitation on the accumulation of Hg in needle biomass and its deposition by litterfall in thirty-one pine plantations spread throughout two biogeographical regions in SW Europe. Well-developed branches of Pinus pinaster were sampled and pine needles were classified according to 4 age classes (y0, y1, y2, y3). The concentration of total Hg (THg) was analyzed in the samples and Hg content in needle biomass and its deposition by litterfall were estimated. The concentration of total Hg (THg) increased with needle age ranging from 9.1 to 32.7 μg Hg kg-1 in the youngest and oldest needles, respectively. The rate of Hg uptake (HgR) three years after needle sprouting was 10.2 ± 2.3 μg Hg kg-1 yr-1, but it decreased with needle age probably due to a diminution in photosynthetic activity as needles get older. The average total Hg stored in needle biomass (HgWt) ranged from 5.6 to 87.8 mg Hg ha-1, with intermediate needle age classes (y1 and y2) accounting for 70% of the total Hg stored in the whole needle biomass. The average deposition flux of Hg through needle litterfall (HgLt) was 1.5 μg Hg m-2 yr-1, with the y2 and y3 needles contributing most to the total Hg flux. The spatial variation of THg, HgWt and HgLt decreased from coastal pine stands, characterized by an oceanic climate, to inland pine stands, a feature closely related to the dominant precipitation regime in the study area. Climatic conditions and needle age are the main factors affecting Hg accumulation in tree foliage, and should be considered for an accurate assessment of forest Hg pools at a regional scale and their potential consequences in the functioning of terrestrial ecosystems.
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Affiliation(s)
- Melissa Méndez-López
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain.
| | - Antía Gómez-Armesto
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Cristina Eimil-Fraga
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo s/n, 27002, Lugo, Spain
| | - Flora Alonso-Vega
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Roque Rodríguez-Soalleiro
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo s/n, 27002, Lugo, Spain
| | - Esperanza Álvarez-Rodríguez
- Departamento de Edafología y Química Agrícola, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo s/n, 27002, Lugo, Spain
| | - Manuel Arias-Estévez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Juan Carlos Nóvoa-Muñoz
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias, As Lagoas s/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental, Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
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Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2021.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Sun T, Wang Z, Zhang X, Niu Z, Chen J. Influences of high-level atmospheric gaseous elemental mercury on methylmercury accumulation in maize (Zea mays L.). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114890. [PMID: 32544787 DOI: 10.1016/j.envpol.2020.114890] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Maize (Zea mays L.) leaves play an important role in stomatal uptake and surface adsorption of atmospheric mercury (Hg). However, the influence of atmospheric gaseous elemental mercury (GEM) on methylmercury (MeHg) accumulation in maize plants is poorly understood. In this study, we conducted a field open-top chambers (OTCs) experiment and a soil Hg-enriched experiment to investigate the response of MeHg accumulation in maize tissues to different GEM levels in the air. Maize upper leaves had a higher average MeHg concentration (0.21 ± 0.08 ng g-1) than bottom leaves (0.15 ± 0.05 ng g-1) in the OTCs experiment, which was inconsistent with that in the soil Hg-enriched experiment (maize upper leaves: 0.41 ± 0.07 ng g-1, maize bottom leaves: 0.60 ± 0.05 ng g-1). Additionally, significantly positive correlations were found between MeHg concentrations in maize leaves and air Hg levels, suggesting that elevated air Hg levels enhanced MeHg accumulation in maize leaves, which was possibly attributed to methylation of Hg on leaf surfaces. Mature maize grains from the OTCs experiment had low MeHg concentrations (0.12-0.23 ng g-1), suggesting a low accumulation capability of MeHg by maize grains. Approximately 93-96% of MeHg and 51-73% of total Hg in maize grains were lost from the grain-filling stage to the grain-ripening stage at all GEM level treatments, implying that self-detoxification in maize grains occurred. MeHg concentrations in maize roots showed a significant linear relationship (R2 = 0.98, p < 0.01) with soil Hg levels, confirming that MeHg in maize roots is primarily from soil. This study provides a new finding that elevated air GEM levels could enhance MeHg accumulation in maize leaves, and self-detoxification may occur in maize grains. Further studies are needed to clarify these mechanisms of Hg methylation on maize leaf surfaces and self-detoxification of Hg by maize grains.
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Affiliation(s)
- Ting Sun
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Western University, Ontario, N6A 3K7, Canada
| | - Zhangwei Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xiaoshan Zhang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhenchuan Niu
- Institute of Earth Environment, Chinese Academy of Science, Xi'an, 710061, China
| | - Jian Chen
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
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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.
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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.
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9
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Tsz-Ki Tsui M, Liu S, Brasso RL, Blum JD, Kwon SY, Ulus Y, Nollet YH, Balogh SJ, Eggert SL, Finlay JC. Controls of Methylmercury Bioaccumulation in Forest Floor Food Webs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:2434-2440. [PMID: 30727732 DOI: 10.1021/acs.est.8b06053] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Compared to the extensive research on aquatic ecosystems, very little is known about the sources and trophic transfer of methylmercury (MeHg) in terrestrial ecosystems. In this study, we examine energy flow and trophic structure using stable carbon (δ13C) and nitrogen (δ15N) isotope ratios, respectively, and MeHg levels in basal resources and terrestrial invertebrates from four temperate forest ecosystems. We show that MeHg levels in biota increased significantly ( p < 0.01) with δ13C and δ15N at all sites, implying the importance of both microbially processed diets (with increased δ13C) and trophic level (with increased δ15N) at which organisms feed, on MeHg levels in forest floor biota. The trophic magnification slopes of MeHg (defined as the slope of log10MeHg vs δ15N) for these forest floor food webs (0.20-0.28) were not significantly different ( p > 0.05) from those observed for diverse temperate freshwater systems (0.24 ± 0.07; n = 78), demonstrating for the first time the nearly equivalent efficiencies with which MeHg moves up the food chain in these contrasting ecosystem types. Our results suggest that in situ production of MeHg within the forest floor and efficient biomagnification both elevate MeHg levels in carnivorous invertebrates in temperate forests, which can contribute to significant bioaccumulation of this neurotoxin in terrestrial apex predators.
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Affiliation(s)
- Martin Tsz-Ki Tsui
- Department of Biology , University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Songnian Liu
- Department of Biology , University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Rebecka L Brasso
- Department of Zoology , Weber State University , Ogden , Utah 84408 , United States
| | - Joel D Blum
- Department of Earth and Environmental Sciences , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering , Pohang University of Science and Technology , Pohang 37673 , South Korea
| | - Yener Ulus
- Department of Biology , University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Yabing H Nollet
- Metropolitan Council Environmental Services , St. Paul , Minnesota 55106 , United States
| | - Steven J Balogh
- Metropolitan Council Environmental Services , St. Paul , Minnesota 55106 , United States
| | - Sue L Eggert
- U.S.D.A. Forest Service , Northern Research Station, Grand Rapids , Minnesota 55744 , United States
| | - Jacques C Finlay
- Department of Ecology, Evolution, and Behavior , University of Minnesota , St. Paul , Minnesota 55108 , United States
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10
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Wang Z, Sun T, Driscoll CT, Yin Y, Zhang X. Mechanism of Accumulation of Methylmercury in Rice ( Oryza sativa L.) in a Mercury Mining Area. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:9749-9757. [PMID: 30129363 DOI: 10.1021/acs.est.8b01783] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Rice consumption is the primary pathway for methylmercury (MeHg) exposure at inland mercury (Hg) mining areas of China. The sources and processes of formation and translocation for MeHg in rice plant are complex and remain largely unknown. In this study, rice ( Oryza sativa L.) was exposed to isotopically labeled dimethylmercury (DMe199Hg) in field experiments using open top chambers to explore the response of MeHg accumulation in rice tissues to different levels of DMe199Hg in air. Rice leaves assimilated DMeHg from air, which was subsequently largely stored in aboveground tissues, including the rice grain, with only a small amount reaching the root. Combining these experimental results with field investigations of DMeHg concentrations in air beneath the rice canopy in a Hg mining area, we estimate that 15.5%, 10.8%, and 8.50% MeHg in the brown rice, the leaf, and the upper stalk, respectively, could be derived from atmospheric sources of DMeHg, while 99.5% of MeHg in rice root originated from the rice soil-water system. These findings help refine the mechanism of MeHg accumulation in rice that, in addition to soil, a fraction of MeHg in rice plants can be derived from DMeHg emissions from flooded rice paddies in Hg mining areas.
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Affiliation(s)
- Zhangwei Wang
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Ting Sun
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering , Syracuse University , 151 Link Hall , Syracuse , New York 13244 , United States
| | - Yongguang Yin
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xiaoshan Zhang
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
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Coufalík P, Meszarosová N, Coufalíková K, Zvěřina O, Komárek J. Determination of methylmercury in cryptogams by means of GC-AFS using enzymatic hydrolysis. Microchem J 2018. [DOI: 10.1016/j.microc.2018.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Eagles-Smith CA, Herring G, Johnson B, Graw R. Conifer density within lake catchments predicts fish mercury concentrations in remote subalpine lakes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 212:279-289. [PMID: 26854697 DOI: 10.1016/j.envpol.2016.01.049] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/16/2016] [Accepted: 01/19/2016] [Indexed: 05/28/2023]
Abstract
Remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited mercury through freshwater food webs, as well as for evaluating the relative importance of mercury loading versus landscape influences on mercury bioaccumulation. The increase in mercury deposition to these systems over the past century, coupled with their limited exposure to direct anthropogenic disturbance make them useful indicators for estimating how changes in mercury emissions may propagate to changes in Hg bioaccumulation and ecological risk. We evaluated mercury concentrations in resident fish from 28 high-elevation, sub-alpine lakes in the Pacific Northwest region of the United States. Fish total mercury (THg) concentrations ranged from 4 to 438 ng/g wet weight, with a geometric mean concentration (±standard error) of 43 ± 2 ng/g ww. Fish THg concentrations were negatively correlated with relative condition factor, indicating that faster growing fish that are in better condition have lower THg concentrations. Across the 28 study lakes, mean THg concentrations of resident salmonid fishes varied as much as 18-fold among lakes. We used a hierarchal statistical approach to evaluate the relative importance of physiological, limnological, and catchment drivers of fish Hg concentrations. Our top statistical model explained 87% of the variability in fish THg concentrations among lakes with four key landscape and limnological variables: catchment conifer density (basal area of conifers within a lake's catchment), lake surface area, aqueous dissolved sulfate, and dissolved organic carbon. Conifer density within a lake's catchment was the most important variable explaining fish THg concentrations across lakes, with THg concentrations differing by more than 400 percent across the forest density spectrum. These results illustrate the importance of landscape characteristics in controlling mercury bioaccumulation in fish.
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Affiliation(s)
- Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis Research Group, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
| | - Garth Herring
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis Research Group, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
| | - Branden Johnson
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis Research Group, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
| | - Rick Graw
- U. S. Department of Agriculture Forest Service, USA
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13
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Kowalski A, Frankowski M. Seasonal variability of mercury concentration in soils, buds and leaves of Acer platanoides and Tilia platyphyllos in central Poland. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:9614-24. [PMID: 26846237 PMCID: PMC4871916 DOI: 10.1007/s11356-016-6179-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/25/2016] [Indexed: 05/14/2023]
Abstract
In this paper, we present the results of mercury concentration in soils, buds and leaves of maple (Acer platanoides-Ap) and linden (Tilia platyphyllos-Tp) collected in four periods of the growing season of trees, i.e. in April (IV), June (VI), August (VIII) and November (IX) in 2013, from the area of Poznań city (Poland). The highest average concentration of mercury for 88 samples was determined in soils and it equaled 65.8 ± 41.7 ng g(-1) (range 14.5-238.9 ng g(-1)); lower average concentration was found in Ap samples (n = 66): 55.4 ± 18.1 ng g(-1) (range 26.5-106.9 ng g(-1)); in Tp samples 50.4 ± 15.8 ng g(-1) (range 23.1-88.7 ng g(-1)) and in 22 samples of Tp buds 40.8 ± 22.7 ng g(-1) (range 12.4-98.7 ng g(-1)) and Ap buds 28.2 ± 13.6 ng g(-1) (range 8.0-59.5 ng g(-1)). Based on the obtained results, it was observed that the highest concentration of mercury in soils occurred in the centre of Poznań city (95.5 ± 39.1 ng g(-1)), and it was two times higher than the concentration of mercury in other parts of the city. Similar dependencies were not observed for the leaf samples of Ap and Tp. It was found that mercury concentrations in the soil and leaves of maple and linden were different depending on the period of the growing season (April to November). Mercury content in the examined samples was higher in the first two research periods (April IV, June VI), and then, in the following periods, the accumulation of mercury decreased both in soil and leaf samples of the two tree species. There was no correlation found between mercury concentration in leaves and mercury concentration in soils during the four research periods (April-November). When considering the transfer coefficient, it was observed that the main source of mercury in leaves is the mercury coming from the atmosphere.
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Affiliation(s)
- Artur Kowalski
- Department of Water and Soil Analysis, Adam Mickiewicz University in Poznań, Umultowska 89b, 61-614, Poznań, Poland
| | - Marcin Frankowski
- Department of Water and Soil Analysis, Adam Mickiewicz University in Poznań, Umultowska 89b, 61-614, Poznań, Poland.
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Gamby RL, Hammerschmidt CR, Costello DM, Lamborg CH, Runkle JR. Deforestation and cultivation mobilize mercury from topsoil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 532:467-473. [PMID: 26100725 DOI: 10.1016/j.scitotenv.2015.06.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/04/2015] [Accepted: 06/04/2015] [Indexed: 06/04/2023]
Abstract
Terrestrial biomass and soils are a primary global reservoir of mercury (Hg) derived from natural and anthropogenic sources; however, relatively little is known about the fate and stability of Hg in the surface soil reservoir and its susceptibility to change as a result of deforestation and cultivation. In southwest Ohio, we measured Hg concentrations in soils of deciduous old- and new-growth forests, as well as fallow grassland and agricultural soils that had once been forested to examine how, over decadal to century time scales, man-made deforestation and cultivation influence Hg mobility from temperate surface soils. Mercury concentrations in surficial soils were significantly greater in the old-growth than new-growth forest, and both forest soils had greater Hg concentrations than cultivated and fallow fields. Differences in Hg:lead ratios between old-growth forest and agricultural topsoils suggest that about half of the Hg lost from deforested and cultivated Ohio soils may have been volatilized and the other half eroded. The estimated mobilization potential of Hg as a result of deforestation was 4.1 mg m(-2), which was proportional to mobilization potentials measured at multiple locations in the Amazon relative to concentrations in forested surface soils. Based on this relationship and an estimate of the global average of Hg concentrations in forested soils, we approximate that about 550 M mol of Hg has been mobilized globally from soil as a result of deforestation during the past two centuries. This estimate is comparable to, if not greater than, the amount of anthropogenic Hg hypothesized by others to have been sequestered by the soil reservoir since Industrialization. Our results suggest that deforestation and soil cultivation are significant anthropogenic processes that exacerbate Hg mobilization from soil and its cycling in the environment.
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Affiliation(s)
- Rebecca L Gamby
- Department of Earth & Environmental Sciences, Wright State University, 3640 Colonel Glenn Hwy., Dayton, OH 45435, United States.
| | - Chad R Hammerschmidt
- Department of Earth & Environmental Sciences, Wright State University, 3640 Colonel Glenn Hwy., Dayton, OH 45435, United States.
| | - David M Costello
- Department of Biological Sciences, Kent State University, Kent, OH 44242, United States.
| | - Carl H Lamborg
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States; Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA 95064, United States.
| | - James R Runkle
- Department of Biological Sciences, Wright State University, 3640 Colonel Glenn Hwy., Dayton, OH 45435, United States.
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Zhou J, Wang Z, Zhang X, Chen J. Distribution and elevated soil pools of mercury in an acidic subtropical forest of southwestern China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2015; 202:187-195. [PMID: 25836382 DOI: 10.1016/j.envpol.2015.03.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/04/2015] [Accepted: 03/10/2015] [Indexed: 06/04/2023]
Abstract
Tieshanping catchment in southwest China was supposed to a large pool of atmospheric mercury. This work was aimed to examine THg (total mercury) concentrations, pools and influence factors in the acidic forest. THg concentrations were highly elevated in the study area, which was significantly depended on TOM (total organic matter) concentrations and altitudinal elevation, whereas negatively correlated with soil pH. The pools of mercury accumulated in soils were correlated strongly with the stocks of TOM and altitude, ranged from 5.9 to 32 mg m(-2) and averaged 14.5 mg m(-2), indicating that the acidic forest was a great sink of atmospheric mercury in southwest China. THg concentrations in stream waters decreased with altitude increasing and regression analyses showed that soil/air exchange flux would be increased with the decrease of altitude. Present results suggest that elevation increasing decreases THg losses as low THg concentrations in runoffs and volatilization from soils.
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Affiliation(s)
- Jun Zhou
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhangwei Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Xiaoshan Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jian Chen
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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16
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Buch AC, Correia MEF, Teixeira DC, Silva-Filho EV. Characterization of soil fauna under the influence of mercury atmospheric deposition in Atlantic Forest, Rio de Janeiro, Brazil. J Environ Sci (China) 2015; 32:217-227. [PMID: 26040748 DOI: 10.1016/j.jes.2015.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 12/20/2014] [Accepted: 12/26/2014] [Indexed: 06/04/2023]
Abstract
The increasing levels of mercury (Hg) found in the atmosphere arising from anthropogenic sources, have been the object of great concern in the past two decades in industrialized countries. Brazil is the seventh country with the highest rate of mercury in the atmosphere. The major input of Hg to ecosystems is through atmospheric deposition (wet and dry), being transported in the atmosphere over large distances. The forest biomes are of strong importance in the atmosphere/soil cycling of elemental Hg through foliar uptake and subsequent transference to the soil through litter, playing an important role as sink of this element. Soil microarthropods are keys to understanding the soil ecosystem, and for such purpose were characterized by the soil fauna of two Units of Forest Conservation of the state of the Rio de Janeiro, inwhich one of the areas suffer quite interference from petrochemicals and industrial anthropogenic activities and other area almost exempts of these perturbations. The results showed that soil and litter of the Atlantic Forest in Brazil tend to stock high mercury concentrations, which could affect the abundance and richness of soil fauna, endangering its biodiversity and thereby the functioning of ecosystems.
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Affiliation(s)
- Andressa Cristhy Buch
- Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-007, Brazil.
| | | | - Daniel Cabral Teixeira
- Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-007, Brazil
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Rolfhus KR, Wiener JG, Haro RJ, Sandheinrich MB, Bailey SW, Seitz BR. Mercury in streams at Grand Portage National Monument (Minnesota, USA): assessment of ecosystem sensitivity and ecological risk. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 514:192-201. [PMID: 25666279 DOI: 10.1016/j.scitotenv.2015.01.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/23/2015] [Accepted: 01/24/2015] [Indexed: 06/04/2023]
Abstract
Mercury (Hg) in water, sediment, soils, seston, and biota were quantified for three streams in the Grand Portage National Monument (GRPO) in far northeastern Minnesota to assess ecosystem contamination and the potential for harmful exposure of piscivorous fish, wildlife, and humans to methylmercury (MeHg). Concentrations of total Hg in water, sediment, and soil were typical of those in forest ecosystems within the region, whereas MeHg concentrations and percent MeHg in these ecosystem components were markedly higher than values reported elsewhere in the western Great Lakes Region. Soils and sediment were Hg-enriched, containing approximately 4-fold more total Hg per unit of organic matter. We hypothesized that localized Hg enrichment was due in part to anthropogenic pollution associated with historic fur-trading activity. Bottom-up forcing of bioaccumulation was evidenced by MeHg concentrations in larval dragonflies, which were near the maxima for dragonflies sampled concurrently from five other national park units in the region. Despite its semi-remote location, GRPO is a Hg-sensitive landscape in which MeHg is produced and bioaccumulated in aquatic food webs to concentrations that pose ecological risks to MeHg-sensitive piscivores, including predatory fish, belted kingfisher, and mink.
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Affiliation(s)
- Kristofer R Rolfhus
- University of Wisconsin-La Crosse, River Studies Center, 1725 State Street, La Crosse, WI 54601, USA.
| | - James G Wiener
- University of Wisconsin-La Crosse, River Studies Center, 1725 State Street, La Crosse, WI 54601, USA.
| | - Roger J Haro
- University of Wisconsin-La Crosse, River Studies Center, 1725 State Street, La Crosse, WI 54601, USA.
| | - Mark B Sandheinrich
- University of Wisconsin-La Crosse, River Studies Center, 1725 State Street, La Crosse, WI 54601, USA.
| | - Sean W Bailey
- University of Wisconsin-La Crosse, River Studies Center, 1725 State Street, La Crosse, WI 54601, USA.
| | - Brandon R Seitz
- National Park Service, Grand Portage National Monument, P.O. Box 426, 170 Mile Creek Road, Grand Portage, MN 55605, USA.
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19
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Matysiak W, Atanackovic J, Katalmohseni H, Byun S, Inskip M, Prestwich W, Priest N, Chin K, Cowan D, Chettle D. In-Vivo Neutron Activation Analysis for Aluminium in Bone: System Upgrade and Improve Data Analysis. ACTA ACUST UNITED AC 2013. [DOI: 10.12943/anr.2013.00015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
An existing NaI(Tl) multidetector array at McMaster University used for in vivo measurement of aluminum by means of neutron activation has been recently upgraded with an in-house built pulse processing system. The new system is capable of collecting spectra in coincidence and anticoincidence modes which allows for better discrimination between the 1.78 MeV 28Al peak and the interfering 38Cl peak. The system is interfaced with Matlab and controlled using a custom graphical user interface, which provides periodic spectral data storage during the acquisition. This feature makes it possible to validate the acquired data and the spectral fitting routines through half-life analysis of the radionuclides. A new set of calibration phantoms spanning a narrower range of aluminum concentrations than employed in the previous study, has also been developed. The combined effect of the new improvements resulted in the minimum detectable level of aluminum in aqueous solutions containing Na, Cl, and Ca in physiological levels, equal to approximately 3 µgAl/gCa.
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Affiliation(s)
- W. Matysiak
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
| | - J. Atanackovic
- Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk, River, ON Canada K0J 1J0
| | - H. Katalmohseni
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
| | - S.H. Byun
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
| | - M. Inskip
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
| | - W.V. Prestwich
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
| | - N. Priest
- Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk, River, ON Canada K0J 1J0
| | - K. Chin
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
| | - D. Cowan
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
| | - D.R. Chettle
- McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8
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Tsui MTK, Blum JD, Kwon SY, Finlay JC, Balogh SJ, Nollet YH. Sources and transfers of methylmercury in adjacent river and forest food webs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10957-64. [PMID: 23033864 DOI: 10.1021/es3019836] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Nearly all ecosystems are contaminated with highly toxic methylmercury (MeHg), but the specific sources and pathways leading to the uptake of MeHg within and among food webs are not well understood. In this study, we report stable mercury (Hg) isotope compositions in food webs in a river and an adjacent forest in northern California and demonstrate the utility of Hg isotopes for studying MeHg sources and cross-habitat transfers. We observed large differences in both δ(202)Hg (mass-dependent fractionation) and Δ(199)Hg (mass-independent fractionation) within both food webs. The majority of isotopic variation within each food web could be accounted for by differing proportions of inorganic Hg [Hg(II)] and MeHg along food chains. We estimated mean isotope values of Hg(II) and MeHg in each habitat and found a large difference in δ(202)Hg between Hg(II) and MeHg (∼2.7‰) in the forest but not in the river (∼0.25‰). This is consistent with in situ Hg(II) methylation in the study river but suggests Hg(II) methylation may not be important in the forest. In fact, the similarity in δ(202)Hg between MeHg in forest food webs and Hg(II) in precipitation suggests that MeHg in forest food webs may be derived from atmospheric sources (e.g., rainfall, fog). Utilizing contrasting δ(202)Hg values between MeHg in river food webs (-1.0‰) and MeHg in forest food webs (+0.7‰), we estimate with a two-source mixing model that ∼55% of MeHg in two riparian spiders is derived from riverine sources while ∼45% of MeHg originates from terrestrial sources. Thus, stable Hg isotopes can provide new information on subtle differences in sources of MeHg and trace MeHg transfers within and among food webs in natural ecosystems.
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Affiliation(s)
- Martin Tsz Ki Tsui
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA.
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Zhang H, Feng X, Zhu J, Sapkota A, Meng B, Yao H, Qin H, Larssen T. Selenium in soil inhibits mercury uptake and translocation in rice (Oryza sativa L.). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10040-10046. [PMID: 22916794 DOI: 10.1021/es302245r] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A great number of studies have confirmed that mercury-selenium (Hg-Se) antagonism is a widespread phenomenon in microorganisms, fish, poultry, humans, and other mammals. However, by comparison, little attention has been paid to plants. To investigate the influence of Se on the uptake and translocation of methylHg/inorganic Hg (MeHg/IHg) in the rice-soil system, we determined the levels of Se, IHg, and MeHg in different parts of rice plants (including the root, stem, leaf, husk, and grain (brown rice)) and corresponding soils of root zones collected from a Hg mined area, where Hg and Se co-occur due to historic Hg mining and retorting activities. The results showed that, in general, the Se levels were inversely related to the levels of both IHg and MeHg in the grains. In addition, a consistent reduction in translocation of both IHg and MeHg in the aerial shoots (i.e., the stem, leaf, husk, and grain) with increasing Se levels in the soils was observed. Furthermore, the Se levels were positively correlated with the IHg levels in the soils and the roots. These results suggest that Se may play an important role in limiting the bioaccessibility, absorption, and translocation/bioaccumulation of both IHg and MeHg in the aerial rice plant, which may be related to the formation of an Hg-Se insoluble complex in the rhizospheres and/or roots.
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Affiliation(s)
- Hua Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
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