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Kondo M, Korre A, Komai T, Watanabe N. Multi-layered physical factors govern mercury release from soil: Implications for predicting the environmental fate of mercury. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 352:120024. [PMID: 38215594 DOI: 10.1016/j.jenvman.2024.120024] [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: 11/22/2023] [Revised: 12/23/2023] [Accepted: 01/02/2024] [Indexed: 01/14/2024]
Abstract
Despite the recognised risks of human exposure to mercury (Hg), the drivers of gaseous elemental mercury (GEM) emissions from the soil remain understudied. In this study, we aimed to identify the environmental parameters that affect the GEM flux from soil and derive the correlations between environmental parameters and GEM flux. Principal component analysis (PCA), factor analysis (FA), and structural equation modelling (SEM) were performed on samples from forest and non-forest sites. The associated results revealed the impact of each environmental parameter on GEM flux, either due to the interaction between the parameters or as a coherent set of parameters. An introductory correlation matrix examining the relationship between two components showed a negative correlation between GEM flux and atmospheric pressure at the two sites, as well as strong correlations between atmospheric pressure and soil temperature. In cases of non-forest open sites with no trees, the PCA and FA results were consistent, indicating that atmospheric pressure, solar irradiance, and soil moisture-defined as primary causality-are largely independent drivers of GEM flux. In contrast, the PCA and FA results for the forest areas with high humidity, tree coverage, and shade were inconsistent, confirming the hypothesis that primary causality affects GEM flux rather than consequent parameters driven by primary causality, such as air and soil temperature and atmospheric humidity. The SEM results provided further evidence for primary and consequent causality as crucial drivers of the GEM flux. This study demonstrates the importance of key primary parameters, such as atmospheric pressure, solar irradiance, and soil moisture content, that can be used to predict mercury release from soils, as well as the importance of consequent parameters, such as air and soil temperature and atmospheric humidity. Monitoring the magnitude of these environmental parameters alone may facilitate the estimation of mercury release from soils and be useful for detailed modelling of soil-air Hg exchange.
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Affiliation(s)
- Monami Kondo
- Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki-aza-aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan.
| | - Anna Korre
- Department of Earth Science and Engineering, Royal School of Mines, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Takeshi Komai
- Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki-aza-aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Noriaki Watanabe
- Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki-aza-aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
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Ci Z, Tang X, Shen W, Chen B. Mercury (Hg) in the "Skin" of the Ocean: Dissolved Gaseous Hg, Total Hg, and Hg Redox Chemistry in Sea Surface Microlayer and Implication for Air-Sea Hg Exchange. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15037-15046. [PMID: 37766473 DOI: 10.1021/acs.est.3c05170] [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: 09/29/2023]
Abstract
The sea surface microlayer (SML) is the uppermost ∼1000 μm of the surface of the ocean. With distinct physicochemical properties and position relative to the adjacent subsurface waters (SSWs), the ubiquitous distribution and high dynamics of the SML greatly regulate the global air-sea gas exchange and biogeochemistry. Mercury (Hg) redox chemistry in surface seawaters and air-sea exchange of gaseous Hg (mainly Hg(0)) fundamentally control the global oceanic Hg cycle. However, the occurrence and transformation of Hg in the SML have been poorly quantified. Here we optimize the traditional SML sampling system to make it more suitable for dissolved gaseous Hg (DGM, mainly Hg(0)) sampling. We then assess the temporal and spatial variability of DGM, total Hg, dissolved organic carbon (DOC), and Hg redox chemistry in the SML and SSWs of diverse marine environments. Our data suggest a general DGM, total Hg, and DOC enrichment in the SML relative to the SSWs but with complex variability in time and space. The incubation experiments further reveal the complex characteristics of Hg redox chemistry between the SML and SSWs. We discuss important implications of the SML Hg cycle on air-sea Hg exchange and suggest wider investigations of the SML Hg cycle in the global hydrosphere.
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Affiliation(s)
- Zhijia Ci
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Xiong Tang
- Guangdong Eco-Engineering Polytechnic, Guangzhou 510520, China
| | - Wenjie Shen
- School of Earth Sciences and Engineering, Sun Yat-sen University, Zhuhai 519082, China
- Guangdong Key Laboratory of Geological Process and Mineral Resources Exploration, Zhuhai 519082, China
| | - Baowei Chen
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
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Ci Z, Tang X, Shen W, Chen B. Coastal streams and sewage outfalls: Hot spots of mercury discharge, pollution and cycling in nearshore environments. MARINE POLLUTION BULLETIN 2023; 195:115536. [PMID: 37708606 DOI: 10.1016/j.marpolbul.2023.115536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 09/16/2023]
Abstract
The coastal streams (CSs) and sewage outfalls (SOs) are widely distributed and direct anthropogenic stress on global coastal ecosystems. However, the CS/SO-associated mercury (Hg) discharge, pollution and cycle in nearshore environment are less quantified. Here, we report that total Hg (THg) and methylmercury (MMHg) concentrations in waters of CSs (n = 8) and SOs (n = 15) of the northern China were ∼102 to 103 times of coastal surface waters and 10 to 102 times of major rivers in China and other regions. The CS/SO discharges resulted in the increase of total organic carbon (TOC) contents, THg and MMHg concentrations and TOC-normalized THg and MMHg concentrations in sediments of CS/SO-impacted coasts. The laboratory experiments further illustrated that the CS/SO-impacted sediments characterized with high potentials of dissolved THg and MMHg productions and releases. Our findings indicate that the layout optimization of SOs is able to reduce the Hg risk in coastal environment.
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Affiliation(s)
- Zhijia Ci
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China.
| | - Xiong Tang
- Guangdong Eco-Engineering Polytechnic, Guangzhou 510520, China
| | - Wenjie Shen
- School of Earth Sciences and Engineering, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Key Laboratory of Geological Process and Mineral Resources Exploration, Zhuhai 519082, China
| | - Baowei Chen
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
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4
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Floreani F, Barago N, Klun K, Faganeli J, Covelli S. Dissolved gaseous mercury production and sea-air gaseous exchange in impacted coastal environments of the northern Adriatic Sea. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023:121926. [PMID: 37268218 DOI: 10.1016/j.envpol.2023.121926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/09/2023] [Accepted: 05/28/2023] [Indexed: 06/04/2023]
Abstract
The northern Adriatic Sea is well known for mercury (Hg) contamination mainly due to historical Hg mining which took place in Idrija (Slovenia). The formation of dissolved gaseous mercury (DGM) and its subsequent volatilisation can reduce the amount of Hg available in the water column. In this work, the diurnal patterns of both DGM production and gaseous Hg fluxes at the water-air interface were seasonally evaluated in two selected environments within this area, a highly Hg-impacted, confined fish farm (VN: Val Noghera, Italy) and an open coastal zone less impacted by Hg inputs (PR: Bay of Piran, Slovenia). A floating flux chamber coupled with real-time Hg0 analyser was used for flux estimation in parallel with DGM concentrations determination through in-field incubations. Substantial DGM production was observed at VN (range = 126.0-711.3 pg L-1) driven by both strong photoreduction and possibly dark biotic reduction, resulting in higher values in spring and summer and comparable concentrations throughout both day and night. Significantly lower DGM was observed at PR (range = 21.8-183.4 pg L-1). Surprisingly, comparable Hg0 fluxes were found at the two sites (range VN = 7.43-41.17 ng m-2 h-1, PR = 0-81.49 ng m-2 h-1), likely due to enhanced gaseous exchanges at PR thanks to high water turbulence and to the strong limitation of evasion at VN by water stagnation and expected high DGM oxidation in saltwater. Slight differences between the temporal variation of DGM and fluxes indicate that Hg evasion is more controlled by factors such as water temperature and mixing conditions than DGM concentrations alone. The relative low Hg losses through volatilisation at VN (2.4-4.6% of total Hg) further confirm that static conditions in saltwater environments negatively affect the ability of this process in reducing the amount of Hg retained in the water column, therefore potentially leading to a greater availability for methylation and trophic transfer.
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Affiliation(s)
- Federico Floreani
- Department of Mathematics & Geosciences, University of Trieste, Via E. Weiss 2, 34128, Trieste, Italy; Department of Life Sciences, University of Trieste, Via L. Giorgieri 5, 34127, Trieste, Italy.
| | - Nicolò Barago
- Department of Mathematics & Geosciences, University of Trieste, Via E. Weiss 2, 34128, Trieste, Italy
| | - Katja Klun
- Marine Biology Station, National Institute of Biology, Fornace 41, 6330, Piran, Slovenia
| | - Jadran Faganeli
- Marine Biology Station, National Institute of Biology, Fornace 41, 6330, Piran, Slovenia
| | - Stefano Covelli
- Department of Mathematics & Geosciences, University of Trieste, Via E. Weiss 2, 34128, Trieste, Italy
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Kalinchuk VV. Gaseous elemental mercury and its evasion fluxes in the marine boundary layer of the marginal seas of the northwestern Pacific: Results from two cruises in September-December 2019. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:159711. [PMID: 36302426 DOI: 10.1016/j.scitotenv.2022.159711] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 10/12/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
There are many questions regarding the behavior of mercury in the sea-atmosphere system of the northwestern Pacific. Continuous underway measurements of atmospheric gaseous elemental mercury (GEM) and measurements of sea-air GEM evasion fluxes were carried out in the marginal seas of northwestern Pacific from the South China Sea to the Sea of Okhotsk in fall-winter 2019. The median GEM concentration (1.1 ng/m3) was lower than both the background value and the averages previously observed in these areas. A latitudinal gradient of atmospheric GEM and GEM evasion fluxes with maximum values at southern latitudes was found. The following areas have been identified as potential source areas: the Kurill area of the Pacific Ocean Northeast China, Korean Peninsula, and the territory from the southwest coast of the Yellow Sea to the south of Indochina. Seasonal variations were observed in the Sea of Japan and East China Sea with higher GEM concentrations in winter than in fall. Our data and analysis of published data showed significant relationships between GEM evasion fluxes, latitude and sea surface temperature (SST). It seems that on a global scale, along with the GEM gradient between water and atmosphere, SST is the most significant parameter for sea-air GEM evasion fluxes.
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Affiliation(s)
- Viktor V Kalinchuk
- V.I.Il'ichev Pacific Oceanological Institute of Far Eastern Branch of Russian Academy of Sciences, Vladivostok 690041, Russia.
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Floreani F, Acquavita A, Barago N, Klun K, Faganeli J, Covelli S. Gaseous Mercury Exchange from Water–Air Interface in Differently Impacted Freshwater Environments. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19138149. [PMID: 35805807 PMCID: PMC9266016 DOI: 10.3390/ijerph19138149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/23/2022] [Accepted: 06/30/2022] [Indexed: 01/27/2023]
Abstract
Gaseous exchanges of mercury (Hg) at the water–air interface in contaminated sites strongly influence its fate in the environment. In this study, diurnal gaseous Hg exchanges were seasonally evaluated by means of a floating flux chamber in two freshwater environments impacted by anthropogenic sources of Hg, specifically historical mining activity (Solkan Reservoir, Slovenia) and the chlor-alkali industry (Torviscosa dockyard, Italy), and in a pristine site, Cavazzo Lake (Italy). The highest fluxes (21.88 ± 11.55 ng m−2 h−1) were observed at Solkan, coupled with high dissolved gaseous mercury (DGM) and dissolved Hg (THgD) concentrations. Conversely, low vertical mixing and saltwater intrusion at Torviscosa limited Hg mobility through the water column, with higher Hg concentrations in the deep layer near the contaminated sediments. Consequently, both DGM and THgD in surface water were generally lower at Torviscosa than at Solkan, resulting in lower fluxes (19.01 ± 12.65 ng m−2 h−1). However, at this site, evasion may also be limited by high atmospheric Hg levels related to dispersion of emissions from the nearby chlor-alkali plant. Surprisingly, comparable fluxes (15.56 ± 12.78 ng m−2 h−1) and Hg levels in water were observed at Cavazzo, suggesting a previously unidentified Hg input (atmospheric depositions or local geology). Overall, at all sites the fluxes were higher in the summer and correlated to incident UV radiation and water temperature due to enhanced photo production and diffusivity of DGM, the concentrations of which roughly followed the same seasonal trend.
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Affiliation(s)
- Federico Floreani
- Department of Mathematics & Geosciences, University of Trieste, Via Weiss 2, 34128 Trieste, Italy; (N.B.); (S.C.)
- Department of Life Sciences, University of Trieste, Via Giorgieri 5, 34127 Trieste, Italy
- Correspondence:
| | - Alessandro Acquavita
- ARPA FVG Regional Agency for Environmental Protection of Friuli Venezia Giulia, Via Cairoli 14, 33057 Palmanova, Italy;
| | - Nicolò Barago
- Department of Mathematics & Geosciences, University of Trieste, Via Weiss 2, 34128 Trieste, Italy; (N.B.); (S.C.)
| | - Katja Klun
- Marine Biology Station, National Institute of Biology, Fornace 41, 6330 Piran, Slovenia; (K.K.); (J.F.)
| | - Jadran Faganeli
- Marine Biology Station, National Institute of Biology, Fornace 41, 6330 Piran, Slovenia; (K.K.); (J.F.)
| | - Stefano Covelli
- Department of Mathematics & Geosciences, University of Trieste, Via Weiss 2, 34128 Trieste, Italy; (N.B.); (S.C.)
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Qian Y, Liang Y, Cao Q, Wang Z, Shi Y, Liang H. Concentration and speciation of mercury in atmospheric particulates in the Wuda coal fire area, Inner Mongolia, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:3879-3887. [PMID: 34402015 DOI: 10.1007/s11356-021-15805-2] [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: 06/01/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Coal-seam fire is a source of atmospheric mercury that is difficult to control. The Wuda Coalfield in Inner Mongolia, China, is one of the most severe coal fire disaster areas worldwide and has been burning for more than 50 years. To investigate atmospheric mercury pollution from the Wuda coal fire, gaseous elemental mercury (GEM) concentrations and atmospheric particulate mercury (PHg) speciation were measured using a RA-915+ mercury analyzer and the temperature-programmed desorption method. Near-surface GEM concentrations in the Wuda Coalfield and adjacent urban area were 80 ng m-3 (65-90 ng m-3) and 52 ng m-3 (25-95 ng m-3), respectively, which are far higher than the local background value (22 ng m-3). PHg concentrations in the coalfield and urban area also reached significantly high levels, 33 ng m-3 (25-45 ng m-3) and 22 ng m-3 (14-29 ng m-3), respectively (p < 0.05). There is no clear evidence that PHg combines with organic carbon or elemental carbon, but PHg concentration appears to be controlled by air acidity. PHg mainly exists in inorganic forms, such as HgCl2, HgS, HgO, and Hg(NO3)2·H2O. This work can provide references for the speciation analysis of atmospheric PHg and the safety assessment of environmental mercury.
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Affiliation(s)
- Yahui Qian
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, China
- College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Yanci Liang
- Center for Imaging and Systems Biology, Minzu University of China, Beijing, 100081, China
| | - Qingyi Cao
- College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Zhe Wang
- College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Yunyun Shi
- College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Handong Liang
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, China.
- College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China.
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Glinyanova I, Fomichev V, Asanova N. Are aerosols on the leaves of apricot trees (Prunus armeniaca) signalizing the activity of a hidden paleo-supervolcano in a steppe? ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:57424-57439. [PMID: 34467481 DOI: 10.1007/s11356-021-16135-z] [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: 03/02/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Aerosols on plant leaves make it possible to assess the quality of air in settlements. The purpose of this work was to assess the acidity and specific electrical conductivity of aerosol suspensions (by washing off aerosol particles from the leaves of apricot trees (Prunus armeniaca)), which characterize the air pollution in the residential area of the Svetly Yar settlement (Volgograd region, Russia) during the spring-summer of 2019. The research hypothesis was as follows: Acidic mineralized aerosols with a mixed source are present in Svetly Yar. The differences were checked by the Student's t-test and evaluated at the level of significance of p = 0.05. The results indicated the presence of acidic (pH = 4.56 + 0.02) and highly mineralized aerosols (EC = 130.41 + 0.17 μS/cm) in the ambient air of the Svetly Yar residential area during the spring-summer of 2019 and revealed environmental risks for the population in comparison with aerosol suspensions from a (relatively) clean location (pH = 6.46 + 0.02; EC = 37.61 + 0.19 μS/cm). The authors confirmed their hypothesis in favor of mixed source acidic mineralized aerosols in the residential area of the Svetly Yar village. The anthropogenic sources were the industrial zones of Svetly Yar, the southern part of the city of Volgograd and artificial sedimentation tanks in the southwestern part of Svetly Yar. A natural source of pollution in the vicinity of Svetly Yar may be hidden geologically active structures: faults in the Earth's crust, a salt diapir, an underground ancient semiactive volcanic zone on a steppe, etc.
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Affiliation(s)
- Irina Glinyanova
- Institute of Architecture and Construction of the Volgograd State Technical University, Faculty of Еngineering Systems and Technosphere Safety, 1, Akademicheskaya St., 400074, Volgograd, Russia.
| | - Valery Fomichev
- Department of General and Inorganic Chemistry of Volgograd State Technical University, 28 Lenin Av, 400005, Volgograd, Russia
| | - Natali Asanova
- Department of Applied Mathematics of Volgograd State Technical University, 28 Lenin Av, 400005, Volgograd, Russia
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Huang S, Zhang Y. Interannual Variability of Air-Sea Exchange of Mercury in the Global Ocean: The "Seesaw Effect" in the Equatorial Pacific and Contributions to the Atmosphere. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:7145-7156. [PMID: 33929202 DOI: 10.1021/acs.est.1c00691] [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] [Indexed: 06/12/2023]
Abstract
Air-sea exchange of gaseous elemental mercury (Hg(0)) is influenced by different meteorological factors and the availability of Hg in seawater. Here, we use the MITgcm ocean model to explore the interannual variability of this flux and the influence of oceanographic and atmospheric dynamics. We apply the GEOS-Chem model to further simulate the potential impact of the evasion variability on the atmospheric Hg levels. We find a latitudinal pattern in Hg(0) evasion with a relatively small variability in mid-latitudes (3.1-6.7%) and a large one in the high latitudes and Equator (>10%). Different factors dominate the patterns in the equatorial (wind speed), mid- (oceanic flow and temperature), and high-latitudinal (sea-ice, temperature, and dynamic processes) oceans. A seesaw pattern of Hg(0) evasion anomaly (±5-20%) in the equatorial Pacific is found from November to next January between El Niño and La Niña years, owing to the anomalies in wind speed, temperature, and vertical mixing. Higher atmospheric Hg level (2%-5%) are simulated for Hg(0) evasion fluxes with three-month lag, associated with the suppression of upwelling in the beginning of the El Niño event. Despite of the uncertainties, this study elucidates the spatial patterns of the interannual variability of the ocean Hg(0) evasion flux and its potential impact on atmospheric Hg levels.
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Affiliation(s)
- Shaojian Huang
- School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
| | - Yanxu Zhang
- School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
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Spatial Distribution and Biomonitoring of Atmospheric Mercury Concentrations over a Contaminated Coastal Lagoon (Northern Adriatic, Italy). ATMOSPHERE 2020. [DOI: 10.3390/atmos11121280] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The Marano and Grado Lagoon (Northern Adriatic Sea) has been affected by mercury (Hg) contamination coming from two sources, mining activity and discharges from a chlor-alkali plant (CAP). Sediments and water contamination have been previously well characterised, but little is known about the atmospheric compartment, where Hg is easily emitted and can persist for a long time as gaseous elemental mercury (GEM). In this work, atmospheric GEM levels and its spatial distribution over the lagoon were monitored at several sites by means of both continuous discrete instrumental measurements over several months and the determination of Hg bioaccumulated in lichens (Xanthoria parietina L.). Average GEM levels varied from 1.80 ± 0.74 to 3.04 ± 0.66 ng m−3, whereas Hg in lichens ranged between 0.06 to 0.40 mg kg−1. In both cases, the highest values were found downwind of the CAP, but excluding this point, spatial patterns of Hg in the atmosphere and lichens reflected the concentration of this metal in the sediments of the lagoon, showing a decrease moving westward. These results could indicate that the lagoon acts as a secondary source of Hg into the atmosphere: future work is needed to characterise the quantity of releases and depositions at different environments inside the lagoon.
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