scholarly journals Effect of sources and meteorological conditions on the concentration and distribution of gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Daniel Prete
Keyword(s):  
Rural Areas ◽  
Elemental Mercury ◽  
Average Concentration ◽  
Meteorological Conditions ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Data Set ◽  
Gaseous Elemental Mercury ◽  
Regional Sources ◽  
High Mercury

Atmospheric gaseous elemental mercury (GEM) and meteorological parameters were monitored at two sites in downtown Toronto, Canada from Oct. 2015 to Oct. 2016 using Tekran 2537A mercury vapour analyzers. The average concentration was found to be 1.78 ± 0.89 ng/m3 for Kerr Hall North (KHN) and 1.46 ± 0.54 ng/m3 for Jorgenson Hall (JOR) site. Analysis of the data reveals that sporadic events of high mercury concentration are related to local sources. Comparing this data set with that collected in 2004 revealed that the average atmospheric GEM concentration in downtown Toronto dropped from 4.5 ng/m3 to 1.78 ng/m3. Decreases in GEM were also observed over the same period in rural areas as measured by CAMNet. The decrease might be a result of policy change, as three key national and provincial environmental policies have been enacted since 2004. The data collected in Toronto suggest GEM concentration and distribution are influenced by local and regional sources, meteorological conditions, and changes in environmental policy.

scholarly journals Effect of sources and meteorological conditions on the concentration and distribution of gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Daniel Prete
Keyword(s):  
Rural Areas ◽  
Elemental Mercury ◽  
Average Concentration ◽  
Meteorological Conditions ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Data Set ◽  
Gaseous Elemental Mercury ◽  
Regional Sources ◽  
High Mercury

Atmospheric gaseous elemental mercury (GEM) and meteorological parameters were monitored at two sites in downtown Toronto, Canada from Oct. 2015 to Oct. 2016 using Tekran 2537A mercury vapour analyzers. The average concentration was found to be 1.78 ± 0.89 ng/m3 for Kerr Hall North (KHN) and 1.46 ± 0.54 ng/m3 for Jorgenson Hall (JOR) site. Analysis of the data reveals that sporadic events of high mercury concentration are related to local sources. Comparing this data set with that collected in 2004 revealed that the average atmospheric GEM concentration in downtown Toronto dropped from 4.5 ng/m3 to 1.78 ng/m3. Decreases in GEM were also observed over the same period in rural areas as measured by CAMNet. The decrease might be a result of policy change, as three key national and provincial environmental policies have been enacted since 2004. The data collected in Toronto suggest GEM concentration and distribution are influenced by local and regional sources, meteorological conditions, and changes in environmental policy.

scholarly journals A comparison of methyl and gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Elaine Cairns
Keyword(s):  
Urban Areas ◽  
Elemental Mercury ◽  
Point Sources ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Mercury Species ◽  
Gaseous Elemental Mercury ◽  
Location Function ◽  
Air Circulation ◽  
The City

This study was carried out to compare the levels of mercury species, i.e., elemental mercury (Hg°) and methyl mercury (MeHg), in indoor and outdoor air in urban areas in Canada. Offices, laboratories for undergraduate studies, and laboratories for research, in a public building located in the downtown core of the city of Toronto, were selected. Hg° was measured using an automated mercury vapour analyzer. MeHg in the air was collected using a carbotrap, and the trapped MeHg was thermally desorbed and analyzed using a CVAFS. The results showed that both indoor MeHg and Hg° levels were related to location function and air circulation. Outdoor MeHg levels were significantly elevated, ranging between 21 and 41% of total mercury (THg) levels, compared to those reported from previous studies. Outdoor Hg° fluctuations were not found to be significantly related to temperature or sunlight exposure, and outdoor MeHg levels were connected to soil and vegetation abundance. Average indoor Hg° levels were found to be between 1.4 and 15 times higher than outdoor levels, whereas MeHg indoor levels were not consistently higher than outdoor levels. Although the mercury concentrations in the indoor environment are still lower than the safety standard for Hg° and organic mercury, they are comparable to those observed near point sources. Thus, indoor air can be a source of mercury to the atmosphere.

scholarly journals A comparison of methyl and gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Elaine Cairns
Keyword(s):  
Urban Areas ◽  
Elemental Mercury ◽  
Point Sources ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Mercury Species ◽  
Gaseous Elemental Mercury ◽  
Location Function ◽  
Air Circulation ◽  
The City

This study was carried out to compare the levels of mercury species, i.e., elemental mercury (Hg°) and methyl mercury (MeHg), in indoor and outdoor air in urban areas in Canada. Offices, laboratories for undergraduate studies, and laboratories for research, in a public building located in the downtown core of the city of Toronto, were selected. Hg° was measured using an automated mercury vapour analyzer. MeHg in the air was collected using a carbotrap, and the trapped MeHg was thermally desorbed and analyzed using a CVAFS. The results showed that both indoor MeHg and Hg° levels were related to location function and air circulation. Outdoor MeHg levels were significantly elevated, ranging between 21 and 41% of total mercury (THg) levels, compared to those reported from previous studies. Outdoor Hg° fluctuations were not found to be significantly related to temperature or sunlight exposure, and outdoor MeHg levels were connected to soil and vegetation abundance. Average indoor Hg° levels were found to be between 1.4 and 15 times higher than outdoor levels, whereas MeHg indoor levels were not consistently higher than outdoor levels. Although the mercury concentrations in the indoor environment are still lower than the safety standard for Hg° and organic mercury, they are comparable to those observed near point sources. Thus, indoor air can be a source of mercury to the atmosphere.

scholarly journals Fluxes of Gaseous Elemental Mercury on a Mediterranean Coastal Grassland

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 485
Author(s):  
Christiana Polyzou ◽  
Glykeria Loupa ◽  
Aikaterini Trepekli ◽  
Spyridon Rapsomanikis
Keyword(s):  
Turbulent Mixing ◽  
Rural Areas ◽  
Similarity Theory ◽  
Atmospheric Stability ◽  
Elemental Mercury ◽  
Mean Value ◽  
Potential Influence ◽  
Northern Greece ◽  
Gaseous Elemental Mercury ◽  
Rain Events

Coastal rural areas can be a source of elemental mercury, but the potential influence of their topographic and climatic particularities on gaseous elemental mercury (GEM) fluxes have not been investigated extensively. In this study, gaseous elemental mercury was measured over Mediterranean coastal grassland located in Northern Greece from 2014 to 2015 and GEM fluxes were evaluated utilizing Monin–Obukhov similarity theory. The GEM fluxes ranged from –50.30 to 109.69 ng m−2 h−1 with a mean value equal to 10.50 ± 19.14 ng m−2 h−1. Concerning the peak events, with high positive and low negative GEM fluxes, those were recorded from the morning until the evening. Rain events were a strong contributing factor for enhanced GEM fluxes. The enhanced turbulent mixing under daytime unstable conditions led to greater evasion and positive GEM fluxes, while, during nighttime periods, the GEM evasion is lower, indicating the effect of atmospheric stability on GEM fluxes. The coastal grassland with its specific characteristics influences the GEM fluxes and this area could be characterized as a source of elemental mercury. This study is one of the rare efforts in the research community to estimate GEM fluxes in a coastal natural site based on aerodynamic gradient method.

scholarly journals Previously unaccounted atmospheric mercury deposition in a midlatitude deciduous forest

2021 ◽  
Vol 118 (29) ◽  
pp. e2105477118
Author(s):  
Daniel Obrist ◽  
Eric M. Roy ◽  
Jamie L. Harrison ◽  
Charlotte F. Kwong ◽  
J. William Munger ◽  
...  
Keyword(s):  
Deciduous Forest ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Aquatic Biota ◽  
Carbon Dioxide Assimilation ◽  
Mercury Deposition ◽  
Gaseous Elemental Mercury ◽  
Photosynthetic Carbon ◽  
Proxy Measure ◽  
High Mercury

Mercury is toxic to wildlife and humans, and forests are thought to be a globally important sink for gaseous elemental mercury (GEM) deposition from the atmosphere. Yet there are currently no annual GEM deposition measurements over rural forests. Here we present measurements of ecosystem–atmosphere GEM exchange using tower-based micrometeorological methods in a midlatitude hardwood forest. We measured an annual GEM deposition of 25.1 µg ⋅ m−2 (95% CI: 23.2 to 26.7 1 µg ⋅ m−2), which is five times larger than wet deposition of mercury from the atmosphere. Our observed annual GEM deposition accounts for 76% of total atmospheric mercury deposition and also is three times greater than litterfall mercury deposition, which has previously been used as a proxy measure for GEM deposition in forests. Plant GEM uptake is the dominant driver for ecosystem GEM deposition based on seasonal and diel dynamics that show the forest GEM sink to be largest during active vegetation growing periods and middays, analogous to photosynthetic carbon dioxide assimilation. Soils and litter on the forest floor are additional GEM sinks throughout the year. Our study suggests that mercury loading to this forest was underestimated by a factor of about two and that global forests may constitute a much larger global GEM sink than currently proposed. The larger than anticipated forest GEM sink may explain the high mercury loads observed in soils across rural forests, which impair water quality and aquatic biota via watershed Hg export.

scholarly journals Mercury Accumulation in Marine Sediments – A Comparison of an Upwelling Area and Two Large River Mouths

2021 ◽  
Vol 8 ◽  
Author(s):  
Sara Zaferani ◽  
Harald Biester
Keyword(s):  
Elemental Mercury ◽  
Congo Basin ◽  
Geochemical Data ◽  
Minor Importance ◽  
Accumulation Rates ◽  
Data Set ◽  
Gaseous Elemental Mercury ◽  
Organic Particles ◽  
Upwelling Area ◽  
Hg Accumulation

Understanding marine mercury (Hg) biogeochemistry is crucial, as the consumption of Hg-enriched ocean fish is the most important pathway of Hg uptake in humans. Although ocean sediments are seen as the ultimate Hg sink, marine sediment studies on Hg accumulation are still rare. In this context, studying Hg behavior in the marine environment, especially in upwelling environments, is of particular interest due to its importance in these great upwelling regions for the global fishery. There are contradictory statements about the fate of Hg in upwelling regions. Some studies have suggested high biotic reduction of oxidized Hg and gaseous elemental mercury evasion to the atmosphere. More recent work has suggested that in upwelling regions, where productivity is high, evasion of gaseous elemental mercury is diminished due to scavenging and sedimentation of Hg by organic particles. In this study, we compared Hg concentrations and accumulation rates in the past ∼4,300 and 19,400 years derived from sediment cores collected in the Peruvian upwelling region (Peru Margin) and compared them with those of two other cores collected from the sediment fan of the Amazon and a core from the Congo Basin, which is influenced by both seasonal coastal upwelling and discharge from the river. Median Hg concentrations were higher at the Peru Margin (90.7 μg kg–1) and in the Congo Basin (93.4 μg kg–1) than in the Amazon Fan (35.8 μg kg–1). The average Hg accumulation rates in sediments from the Peru Margin (178 μg m–2 yr–1) were factors of ∼4 and ∼39 times higher than those from the Congo Basin (46.7 μg m–2 yr–1) and Amazon Fan (4.52 μg m–2 yr–1), respectively. Principal component analysis (PCA) of the geochemical data set reveals that Amazon Fan sediments are strongly influenced by the deposition of terrestrial material, which is of less importance in the Congo Basin and of minor importance in Peru Margin sediments. Accordingly, Hg export to sediments in upwelling areas largely surpasses that in fans of large rivers that drain large terrestrial catchments. The high Hg accumulation rates in the sediments from the upwelling area and the minor influence of terrestrial Hg fluxes there suggest that atmospheric-derived Hg in upwelling areas is effectively exported to the sediments through scavenging by organic particles.

scholarly journals Fluxes of Gaseous Elemental Mercury at a Mediterranean Coastal Grassland

2019 ◽  
Author(s):  
Christiana Polyzou ◽  
Glykeria Loupa ◽  
Aikaterini Trepekli ◽  
Spyridon Rapsomanikis
Keyword(s):  
Turbulent Mixing ◽  
Rural Areas ◽  
Similarity Theory ◽  
Atmospheric Stability ◽  
Elemental Mercury ◽  
Mean Value ◽  
Potential Influence ◽  
Northern Greece ◽  
Gaseous Elemental Mercury ◽  
Rain Events

Coastal rural areas can be a source of elemental mercury, but the potential influence of their topographic and climatic particularities on gaseous elemental mercury (GEM) fluxes have not been investigated extensively. In this study gaseous elemental mercury was measured over Mediterranean coastal grassland located at Northern Greece from 2014 to 2015 and GEM fluxes were evaluated utilizing Monin-Obukhov similarity theory. The GEM fluxes ranged from -50.30 to 109.695 ng m-2 h-1 with a mean value equal to 10.501 ng m-2 h-1 ± 19.14 ng m-2 h-1. Concerning the peak events, with high positive and low negative GEM fluxes, those were recorded from the morning until the evening. Rain events were a strong contributing factor for enhanced GEM fluxes. The enhanced turbulent mixing under daytime unstable conditions led to greater evasion and positive GEM fluxes while during nighttime periods the GEM evasion is lower indicating the effect of atmospheric stability on GEM fluxes. The coastal grassland with its specific characteristics influences the GEM fluxes and this area could be characterized as source of elemental mercury. This study is one of the rare efforts in the research community to estimate GEM fluxes in a coastal natural site based on aerodynamic gradient method.

scholarly journals Air Concentrations of Gaseous Elemental Mercury and Vegetation–Air Fluxes within Saltmarshes of the Tagus Estuary, Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 228
Author(s):  
Rute Cesário ◽  
Nelson J. O’Driscoll ◽  
Sara Justino ◽  
Claire E. Wilson ◽  
Carlos E. Monteiro ◽  
...  
Keyword(s):  
Leaf Area ◽  
Elemental Mercury ◽  
Ambient Air ◽  
Tagus Estuary ◽  
Contaminated Site ◽  
Gaseous Elemental Mercury ◽  
Mercury Flux ◽  
Sarcocornia Fruticosa ◽  
Air Concentrations

In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged between 1.08–18.15 ng m−3 in CN and 1.18–3.53 ng m−3 in ALC. In CN, most of the high Hg(0) levels occurred during nighttime, while the opposite was observed at ALC, suggesting that photoreduction was not driving the air Hg(0) concentrations at the contaminated site. Vegetation–air Hg(0) fluxes were low in ALC and ranged from −0.76 to 1.52 ng m−2 (leaf area) h−1 for Hp and from −0.40 to 1.28 ng m−2 (leaf area) h−1 for Sf. In CN, higher Hg fluxes were observed for both plants, ranging from −9.90 to 15.45 ng m−2 (leaf area) h−1 for Hp and from −8.93 to 12.58 ng m−2 (leaf area) h−1 for Sf. Mercury flux results at CN were considered less reliable due to large and fast variations in the ambient air concentrations of Hg(0), which may have been influenced by emissions from the nearby chlor-alkali plant, or historical contamination. Improved experimental setup, the influence of high local Hg concentrations and the seasonal activity of the plants must be considered when assessing vegetation–air Hg(0) fluxes in Hg-contaminated areas.

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