scholarly journals Total Atmospheric Mercury Deposition in Forest Areas in Korea

2016 ◽  
Author(s):  
Jin-Su Han ◽  
Yong-Seok Seo ◽  
Moon-Kyung Kim ◽  
Thomas M. Holsen ◽  
Seung-Muk Yi
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Deciduous Forest ◽  
Atmospheric Mercury ◽  
Litter Production ◽  
Mercury Deposition ◽  
Temperate Deciduous Forest ◽  
Deposition Fluxes ◽  
Mercury Volatilization ◽  
High Precipitation

Abstract. Atmospheric mercury dry and wet deposition, mercury in throughfall and litterfall, and mercury volatilization from soil were measured during August 2008 to February 2010 in a temperate deciduous forest in Korea. The yearly estimated mercury budget was calculated using two input approaches. For this location the annual mercury accumulation was estimated to be 6.8 μg m-2 yr-1 or 3.9 μg m-2 yr-1 depending on the approach used. Cumulative wet and throughfall fluxes were 4.3 and 6.7 μg m-2 yr-1, respectively. The annual litterfall flux was 4.6 μg m-2 yr-1 and was highest from October to December due to the increased litter production during that period. The annual Hg emission flux from soil was 6.8 μg m-2 yr-1. The overall ratio of wet deposition, throughfall, and litterfall was 1 : 1.6 : 1.1. Cumulative dry deposition fluxes of gaseous oxidized mercury (GOM) were highest in spring 2009 (10.0 ± 2.0 μg m-2 yr-1), followed by summer 2009 (5.8 ± 4.2μg m-2 yr-1), winter 2008 (5.1 ± 5.0 μg m-2 yr-1), winter 2009 (4.6 ± 5.7 μg m-2 yr-1), fall 2008 (1.9 ± 1.0 μg m-2 yr-1) and fall 2009 (1.2 ± 1.4 μg m-2 yr-1) while dry deposition fluxes for particulate bound mercury (PBM) were highest in summer 2009 (9.6 ± 9.0 μg m-2 yr-1), followed by winter 2009 (5.3 ± 5.9 μg m-2 yr-1), winter 2008 (3.8 ± 2.0 μg m-2 yr-1), spring 2009 (3.3 ± 2.6 μg m-2 yr-1), fall 2008 (3.0 ± 1.7 μg m-2 yr-1) and fall 2009 (1.2 ± 0.4 μg m-2 yr-1). The VWM TM concentration in throughfall (14.4 ± 7.1 ng L-1) was about two times higher than that in wet deposition (5.9 ± 3.8 ng L-1). Wet deposition and throughfall fluxes were higher in summer than those in other seasons possibly due to a high precipitation depth.

scholarly journals Total atmospheric mercury deposition in forested areas in South Korea

2016 ◽  
Vol 16 (12) ◽  
pp. 7653-7662 ◽  
Author(s):  
Jin-Su Han ◽  
Yong-Seok Seo ◽  
Moon-Kyung Kim ◽  
Thomas M. Holsen ◽  
Seung-Muk Yi
Keyword(s):  
South Korea ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Deciduous Forest ◽  
Atmospheric Mercury ◽  
Deposition Flux ◽  
Mercury Deposition ◽  
Temperate Deciduous Forest ◽  
Deposition Fluxes ◽  
Forested Areas

Abstract. In this study, mercury (Hg) was sampled weekly in dry and wet deposition and throughfall and monthly in litterfall, and as it was volatilized from soil from August 2008 to February 2010 to identify the factors influencing the amount of atmospheric Hg deposited to forested areas in a temperate deciduous forest in South Korea. For this location there was no significant correlation between the estimated monthly dry deposition flux (litterfall + throughfall – wet deposition) (6.7 µg m−2 yr−1) and directly measured dry deposition (9.9 µg m−2 yr−1) likely due primarily to Hg losses from the litterfall collector. Dry deposition fluxes in cold seasons (fall and winter) were lower than in warmer seasons (spring and summer). The volume-weighted mean (VWM) Hg concentrations in both precipitation and throughfall were highest in winter, likely due to increased scavenging by snow events. Since South Korea experiences abundant rainfall in summer, VWM Hg concentrations in summer were lower than in other seasons. Litterfall fluxes were highest in the late fall to early winter, when leaves were dropped from the trees (September to November). The cumulative annual Hg emission flux from soil was 6.8 µg m−2 yr−1. Based on these data, the yearly deposition fluxes of Hg calculated using two input approaches (wet deposition + dry deposition or throughfall + litterfall) were 6.8 and 3.6 µg m−2 yr−1, respectively. This is the first reported study which measured the amount of atmospheric Hg deposited to forested areas in South Korea, and thus our results provide useful information to compare against data related to Hg fate and transport in this part of the world.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2014 ◽  
Vol 14 (5) ◽  
pp. 2233-2244 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractionated particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume-weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban North America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, as well as nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium, and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of the HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer, while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal, with two peaks in the bins of < 0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

scholarly journals Atmospheric mercury deposition over the land surfaces and the associated uncertainties in observations and simulations: a critical review

2019 ◽  
Vol 19 (24) ◽  
pp. 15587-15608 ◽  
Author(s):  
Lei Zhang ◽  
Peisheng Zhou ◽  
Shuzhen Cao ◽  
Yu Zhao
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Quantitative Methods ◽  
Experimental System ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Future Research ◽  
Observation Data ◽  
Mercury Deposition ◽  
Land Surfaces

Abstract. One of the most important processes in the global mercury (Hg) biogeochemical cycling is the deposition of atmospheric Hg, including gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM), to the land surfaces. Results of wet, dry, and forest Hg deposition from global observation networks, individual monitoring studies, and observation-based simulations have been reviewed in this study. Uncertainties in the observation and simulation of global speciated atmospheric Hg deposition to the land surfaces have been systemically estimated based on assessment of commonly used observation methods, campaign results for comparison of different methods, model evaluation with observation data, and sensitivity analysis for model parameterization. The uncertainties of GOM and PBM dry deposition measurements come from the interference of unwanted Hg forms or incomplete capture of targeted Hg forms, while that of GEM dry deposition observation originates from the lack of a standardized experimental system and operating procedure. The large biases in the measurements of GOM and PBM concentrations and the high sensitivities of key parameters in resistance models lead to high uncertainties in GOM and PBM dry deposition simulation. Non-precipitation Hg wet deposition could play a crucial role in alpine and coastal regions, and its high uncertainties in both observation and simulation affect the overall uncertainties of Hg wet deposition. The overall uncertainties in the observation and simulation of the total global Hg deposition were estimated to be ± (25–50) % and ± (45–70) %, respectively, with the largest contributions from dry deposition. According to the results from uncertainty analysis, future research needs were recommended, among which a global Hg dry deposition network, unified methods for GOM and PBM dry deposition measurements, quantitative methods for GOM speciation, campaigns for comprehensive forest Hg behavior, and more efforts in long-term Hg deposition monitoring in Asia are the top priorities.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2013 ◽  
Vol 13 (11) ◽  
pp. 28309-28341 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractioned particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, and nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal with two peaks in the bins of <0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

scholarly journals Spatial distribution of mercury deposition fluxes in Wanshan Hg mining area, Guizhou province, China

2012 ◽  
Vol 12 (14) ◽  
pp. 6207-6218 ◽  
Author(s):  
Z. H. Dai ◽  
X. B. Feng ◽  
J. Sommar ◽  
P. Li ◽  
X. W. Fu
Keyword(s):  
Spatial Distribution ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Ambient Air ◽  
Mining Area ◽  
Atmospheric Mercury ◽  
Guizhou Province ◽  
Mining Activities ◽  
Deposition Fluxes ◽  
Hg Mining

Abstract. The legacy of long-term mining activities in Wanshan mercury (Hg) mining area (WMMA), Guizhou, China including a series of environmental issues related to Hg pollution. The spatial distribution of gaseous elemental mercury (Hg0) concentrations in ambient air were monitored using a mobile RA-915+ Zeeman Mercury Analyzer during daytime and night time in May 2010. The data imply that calcines and mine wastes piles located at Dashuixi and on-going artisanal Hg mining activities at Supeng were major sources of atmospheric mercury in WMMA. For a full year (May 2010 to May 2011), sampling of precipitation and throughfall were conducted on a weekly basis at three sites (Shenchong, Dashuixi, and Supeng) within WMMA. Hg in deposition was characterized by analysis of total Hg (THg) and dissolved Hg (DHg) concentrations. The corresponding data exhibit a high degree of variability, both temporarily and spatially. The volume-weighted mean THg concentrations in precipitation and throughfall samples were 502.6 ng l−1 and 977.8 ng l−1 at Shenchong, 814.1 ng l−1and 3392.1 ng l−1 at Dashuixi, 7490.1 ng l−1and 9641.5 ng l−1 at Supeng, respectively. THg was enhanced in throughfall compared to wet deposition samples by up to a factor of 7. The annual wet Hg deposition fluxes were 29.1, 68.8 and 593.1 μg m−2 yr−1 at Shenchong, Dashuixi and Supeng, respectively, while the annual dry Hg deposition fluxes were estimated to be 378.9, 2613.6 and 6178 μg m−2 yr−1 at these sites, respectively. Dry deposition played a dominant role in total atmospheric Hg deposition in WMMA since the dry deposition fluxes were 10.4–37.9 times higher than the wet deposition fluxes during the whole sample period. Our data showed that air deposition was still an important pathway of Hg contamination to the local environment in WMMA.

scholarly journals Global deposition of speciated atmospheric mercury to terrestrial surfaces: an overview

2019 ◽  
Author(s):  
Lei Zhang ◽  
Peisheng Zhou ◽  
Shuzhen Cao ◽  
Yu Zhao
Keyword(s):  
Dry Deposition ◽  
Urban Areas ◽  
Wet Deposition ◽  
Current Knowledge ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Future Research ◽  
Observation System ◽  
Mercury Deposition ◽  
Gaseous Elemental Mercury

Abstract. One of the most important processes in the global mercury biogeochemical cycling is the deposition of atmospheric mercury, including gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM), to terrestrial surfaces. In this paper, methods for the observation of wet, dry, litterfall, throughfall, and cloud/fog deposition and models for mercury dry deposition are reviewed. Surrogate surface methods with cation exchange membranes are widely used for GOM dry deposition measurements, while observation methods for GEM dry deposition are more diverse. The methodology for Hg wet deposition is more mature, but the influence of cloud/fog scavenging is easy to neglect. Dry deposition models for speciated mercury have high uncertainties owing to the presence of sensitive parameters related to GOM chemical forms. Observation networks for mercury wet deposition have been developed worldwide, with the Global Mercury Observation System (GMOS) covering the northern hemisphere, the tropics, and the southern hemisphere. Wet deposition implies the spatial distribution of atmospheric mercury pollution, while GOM dry deposition depends highly on the elevation. Litterfall Hg deposition is crucial to forests. Urban areas have high wet deposition and PBM dry deposition because of high reactive mercury levels. Grasslands and forests have significant GOM and GEM dry deposition, respectively. Evergreen broadleaf forests bear high litterfall Hg deposition. Future research needs have been proposed based on the current knowledge of global mercury deposition to terrestrial surfaces.

scholarly journals Spatial distribution of mercury deposition fluxes in Wanshan Hg mining area, Guizhou, China

2012 ◽  
Vol 12 (2) ◽  
pp. 5739-5769 ◽  
Author(s):  
Z. H. Dai ◽  
X. B. Feng ◽  
X. W. Fu ◽  
P. Li
Keyword(s):  
Spatial Distribution ◽  
Dry Deposition ◽  
Dominant Role ◽  
Ambient Air ◽  
Mining Area ◽  
Atmospheric Mercury ◽  
Mercury Deposition ◽  
Night Time ◽  
Deposition Fluxes ◽  
Hg Mining

Abstract. A long-term mining history introduced a series of environmental problems in Wanshan Hg mining area, Guizhou, China. The spatial distribution of gaseous elemental Hg (Hg0) concentrations in ambient air were investigated using RA-915+ Zeeman Mercury Analyzer during day time and night time in May 2010, which showed that calcines and mine wastes piles located at Dashuixi and on-going artisanal Hg mining activities at Supeng were major sources of atmospheric mercury in Wanshan Hg mining area. Meanwhile, both precipitation and throughfall samples were collected weekly at Shenchong, Dashuixi, and Supeng from May 2010 to May 2011, respectively. Our data showed that the concentrations of different Hg species varied with a large range, and the annual volume-weighted mean total mercury (THg) concentrations in precipitation and throughfall samples were 502.6 ng L−1 and 977.8 ng L−1 at Shenchong, 814.1 ng L−1and 3392.1 ng L−1 at Dashuixi, 7490.1 ng L−1 and 9641.5 ng L−1 at Supeng, respectively. Besides, THg concentrations in all throughfall samples were 1–7 folds higher than those in precipitation samples. The annual wet Hg deposition fluxes were 29.1, 68.8 and 593.1 μg m−2 yr−1 at Shenchong, Dashuixi and Supeng, respectively, while the annual dry Hg deposition fluxes were estimated to be 378.9, 2613.6 and 6178 μg m−2 yr−1 at these sites, respectively. Dry deposition played a dominant role in total atmospheric Hg deposition in Wanshan Hg mining area since the dry deposition fluxes were 10.4–37.9 times higher than the wet deposition fluxes during the whole sample period. Our data showed that air deposition was still an important pathway of Hg contamination to the local environment in Wanshan Hg mining area.

scholarly journals Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

2013 ◽  
Vol 13 (8) ◽  
pp. 21801-21835
Author(s):  
K. Osada ◽  
S. Ura ◽  
M. Kagawa ◽  
M. Mikami ◽  
T. Y. Tanaka ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Mineral Dust ◽  
Temporal Variations ◽  
Dust Particles ◽  
Insoluble Residue ◽  
Spatial Distributions ◽  
Dust Deposition ◽  
Deposition Fluxes ◽  
Deposition Amount

Abstract. Data of temporal variations and spatial distributions of mineral dust deposition fluxes are very limited in terms of duration, location, and processes of deposition. To ascertain temporal variations and spatial distributions of mineral dust deposition by wet and dry processes, weekly deposition samples were obtained at Sapporo, Toyama, Nagoya, Tottori, Fukuoka, and Cape Hedo (Okinawa) in Japan during October 2008–December 2010 using automatic wet and dry separating samplers. Mineral dust weights in water-insoluble residue were estimated from Fe contents measured using an X-ray fluorescence analyzer. For wet deposition, highest and lowest annual dust fluxes were found at Toyama (9.6 g m−2 yr−1) and at Cape Hedo (1.7 g m−2 yr−1) as average values in 2009 and 2010. Higher wet deposition fluxes were observed at Toyama and Tottori, where frequent precipitation (>60% days per month) was observed during dusty seasons. For dry deposition among Toyama, Tottori, Fukuoka, and Cape Hedo, the highest and lowest annual dust fluxes were found respectively at Fukuoka (5.2 g m−2 yr−1) and at Cape Hedo (2.0 g m−2 yr−1) as average values in 2009 and 2010. Although the seasonal tendency of the monthly dry deposition amount roughly resembled that of monthly days of Kosa dust events, the monthly amount of dry deposition was not proportional to monthly days of the events. Comparison of dry deposition fluxes with vertical distribution of dust particles deduced from Lidar data and coarse particle concentrations suggested that the maximum dust layer height or thickness is an important factor for controlling the dry deposition amount after long-range transport of dust particles. Size distributions of refractory dust particles were obtained using four-stage filtration: >20, >10, >5, and >1 μm diameter. Weight fractions of the sum of >20 μm and 10–20 μm (giant fraction) were higher than 50% for most of the event samples. Irrespective of the deposition type, the giant dust fractions were decreasing generally with increasing distance from the source area, suggesting the selective depletion of larger giant particles during atmospheric transport. Because giant dust particles are an important mass fraction of dust accumulation, especially in the north Pacific where is known as a high-nutrient, low-chlorophyll (HNLC) region, the transport height of giant dust particles is an important factor for studying dust budgets in the atmosphere and their role in biogeochemical cycles.

scholarly journals Model analyses of atmospheric mercury: present air quality and effects of transpacific transport on the United States

2013 ◽  
Vol 13 (4) ◽  
pp. 9849-9893 ◽  
Author(s):  
H. Lei ◽  
X.-Z. Liang ◽  
D. J. Wuebbles ◽  
Z. Tao
Keyword(s):  
United States ◽  
Air Quality ◽  
Wet Deposition ◽  
Total Mercury ◽  
The United States ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Mercury Deposition ◽  
Transpacific Transport ◽  
Mercury Cycle

Abstract. Atmospheric mercury is a toxic air and water pollutant that is of significant concern because of its effects on human health and ecosystems. A mechanistic representation of the atmospheric mercury cycle is developed for the state-of-the-art global climate-chemistry model, CAM-Chem (Community Atmospheric Model with Chemistry). The model simulates the emission, transport, transformation and deposition of atmospheric mercury (Hg) in three forms: elemental mercury (Hg(0)), reactive mercury (Hg(II)), and particulate mercury (PHg). Emissions of mercury include those from human, land, ocean, biomass burning and volcano related sources. Land emissions are calculated based on surface solar radiation flux and skin temperature. A simplified air–sea mercury exchange scheme is used to calculate emissions from the oceans. The chemistry mechanism includes the oxidation of Hg(0) in gaseous phase by ozone with temperature dependence, OH, H2O2 and chlorine. Aqueous chemistry includes both oxidation and reduction of Hg(0). Transport and deposition of mercury species are calculated through adapting the original formulations in CAM-Chem. The CAM-Chem model with mercury is driven by present meteorology to simulate the present mercury air quality during the 1999–2001 periods. The resulting surface concentrations of total gaseous mercury (TGM) are then compared with the observations from worldwide sites. Simulated wet depositions of mercury over the continental United States are compared to the observations from 26 Mercury Deposition Network stations to test the wet deposition simulations. The evaluations of gaseous concentrations and wet deposition confirm a strong capability for the CAM-Chem mercury mechanism to simulate the atmospheric mercury cycle. The results also indicate that mercury pollution in East Asia and Southern Africa is very significant with TGM concentrations above 3.0 ng m−3. The comparison to wet deposition indicates that wet deposition patterns of mercury are more affected by the spatial variability of precipitation. The sensitivity experiments show that 22% of total mercury deposition and 25% of TGM concentrations in the United States are resulted from domestic anthropogenic sources, but only 9% of total mercury deposition and 7% of TGM concentrations are contributed by transpacific transport. However, the contributions of domestic and transpacific sources on the western United States levels of mercury are of comparable magnitude.

scholarly journals Atmospheric wet and litterfall mercury deposition in typical rural and urban areas in China

2016 ◽  
Author(s):  
Xuewu Fu ◽  
Yang Xu ◽  
Xiaofang Lang ◽  
Jun Zhu ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Urban Areas ◽  
Wet Deposition ◽  
Arid Zone ◽  
Atmospheric Mercury ◽  
Urban Site ◽  
Cloud Base ◽  
Subtropical Zone ◽  
Deposition Fluxes ◽  
Precipitation Depth ◽  
Rural Sites

Abstract. Mercury (Hg) concentrations and deposition fluxes in precipitation and litterfall were measured at multiple sites (six rural sites and an urban site) across a broad geographic area in China. The annual deposition fluxes of Hg in precipitation at rural sites and an urban site were 2.0 to 7.2 µg m−2 yr−1 and 12.6 ± 6.5 µg m−2 yr−1, respectively. Wet deposition fluxes of Hg at rural sites showed a clear regional difference with elevated deposition fluxes in the subtropical zone, followed by the temporal zone and arid/semi-arid zone. Precipitation depth is the primary influencing factor causing the variation of wet deposition. Hg fluxes through litterfall ranged from 22.8 to 62.8 µg m−2 yr−1, higher than the wet deposition by a factor of 3.9 to 8.7 fluxes and representing approximately 75 % of the total Hg deposition at the forest sites in China. This suggests that uptake of atmospheric Hg by foliage is the dominant pathway to remove atmospheric mercury in forest ecosystems in China. Wet deposition fluxes of Hg at rural sites of China were generally lower compared to those in North America and Europe, possibly due to a combination of lower precipitation depth, lower GOM concentrations in the troposphere and the generally lower cloud base heights at most sites that washout a smaller amount of GOM and PBM during precipitation events.

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