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Air Mercury Speciation, Foliar Uptake, and Wash-Off along an Urban-Rural GradientStupple, Geoffrey 15 February 2010 (has links)
Mercury (Hg) is a contaminant of global concern due to its long-range atmospheric transport and high toxicity. The focus of this research is on the role of the forest canopy in the accumulation, and delivery of Hg to the soil Hg pool. Particular focus is on the role of atmospheric speciation of Hg on deposition. An urban-rural gradient was examined from Mississauga to Dorset, Ontario, to determine the role of locally emitted Hg: RGM, and PM on deposition. [GEM] was measured to be similar at both sites, and [PM] and [RGM] were greater in the urban location. Seasonal accumulation of Hg on foliar surfaces was dominated by GEM, and similar at the urban (8.74 ng cm-2) and rural (9.80 ng cm-2) locations. Increased [PM] and [RGM] at the urban location resulted in a transient upper canopy Hg pool, and throughfall enrichment at the urban site.
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Air Mercury Speciation, Foliar Uptake, and Wash-Off along an Urban-Rural GradientStupple, Geoffrey 15 February 2010 (has links)
Mercury (Hg) is a contaminant of global concern due to its long-range atmospheric transport and high toxicity. The focus of this research is on the role of the forest canopy in the accumulation, and delivery of Hg to the soil Hg pool. Particular focus is on the role of atmospheric speciation of Hg on deposition. An urban-rural gradient was examined from Mississauga to Dorset, Ontario, to determine the role of locally emitted Hg: RGM, and PM on deposition. [GEM] was measured to be similar at both sites, and [PM] and [RGM] were greater in the urban location. Seasonal accumulation of Hg on foliar surfaces was dominated by GEM, and similar at the urban (8.74 ng cm-2) and rural (9.80 ng cm-2) locations. Increased [PM] and [RGM] at the urban location resulted in a transient upper canopy Hg pool, and throughfall enrichment at the urban site.
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Determination of the mercury content of lichens and comparison to atmospheric mercury levels in the South African Highveld RegionTrüe, A, Panichev, N, Okonkwo, J, Forbes, PBC 01 June 2012 (has links)
Abstract
The concentration of mercury vapour in ambient air is routinely determined using specialised instruments.
As an economical alternative, actively pumped Hopcalite sorbent tubes can be used to trap atmospheric
mercury, which is subsequently analysed by cold vapour atomic absorption spectroscopy. Plant materials
are also readily available in most regions and can be analysed to obtain information on time averaged
atmospheric mercury levels.
Lichen and tree bark samples were collected in the cities of Pretoria and Witbank, dried and acid digested
with subsequent cold vapour atomic absorption spectroscopy. Average mercury concentrations ranging
from 74 to 193 μg.kg-1 were found in lichens from three Pretoria suburbs, whilst average Hg levels of 228
μg.kg-1 were determined in lichens collected in Witbank. The average mercury concentration in tree bark
was consistently lower than in lichens, with concentrations between 28 and 72 μg.kg-1 determined in
samples from three Pretoria suburbs and 75 μg.kg-1 determined in samples taken in Witbank. This study is
the first in South Africa to determine mercury levels in lichens and tree bark.
Average total gaseous mercury concentrations in ambient air at the three Pretoria suburban sites, as
determined by a semi-continuous spectroscopic method using Hopcalite sampling, ranged between 1.6
and 2.5 ng.m-3, while an average of 1.7 ng.m-3 was measured in Witbank over the sampling interval.
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Ab initio investigation of the thermochemistry, spectroscopy and dynamics of reactions between mercury and reactive halogen speciesShepler, Benjamin C., January 2006 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, August 2006. / Includes bibliographical references.
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A study of mercury oxidation and the development of a global predictive kinetic model /Agarwal, Hans, January 2006 (has links)
Thesis (Ph. D.)--Lehigh University, 2006. / Includes vita. Includes bibliographical references (leaves 257-274).
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The influence of tropospheric ozone, hydrothermal systems, and fires on atmospheric mercury emissions from natural sources /Engle, Mark Alan. January 2005 (has links)
Thesis (Ph. D.)--University of Nevada, Reno, 2005. / "December 2005." Includes bibliographical references. Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.
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Assessment of the severity, sources, and meteorological transport of ambient and wet deposited mercury in the Ohio River Valley airshed /Fahrni, Jason K. January 2005 (has links)
Thesis (M.S.)--Ohio University, June, 2005. / Includes bibliographical references (p. 129-135)
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Assessment of the severity, sources, and meteorological transport of ambient and wet deposited mercury in the Ohio River Valley airshedFahrni, Jason K. January 2005 (has links)
Thesis (M.S.)--Ohio University, June, 2005. / Title from PDF t.p. Includes bibliographical references (p. 129-135)
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Measurements of atmospheric mercury, gaseous elemental mercury, and evasional fluxes in the Amundsen Gulf: the role of the sea-ice environmentLatonas, Jeffrey Roman 18 January 2011 (has links)
Mercury (Hg) has been recognized as a contaminant of global concern due to its high toxicity, as well as its ability to mobilize over long distances and biomagnify up through the food chain. The discovery of polar springtime atmospheric mercury depletion events (AMDEs) in the 1990s provides a new mechanism for enhanced atmospheric Hg deposition to the surface environment in the Arctic, yet questions remain on the process leading to AMDEs and the net contribution of AMDEs to Hg loadings to the Arctic marine ecosystem. Here we report the first systematic study of AMDEs over the open ocean conducted in the Amundsen Gulf flaw lead system from February to July 2008. A total of 31 AMDEs were observed which showed clear dependence on local sea ice environment and meteorological conditions. Enhanced concentrations of dissolved gaseous mercury were also measured in both under ice and open water conditions. Our results confirm that the sea ice environment plays a large role in Hg dynamics in the Arctic Ocean.
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Measurements of atmospheric mercury, gaseous elemental mercury, and evasional fluxes in the Amundsen Gulf: the role of the sea-ice environmentLatonas, Jeffrey Roman 18 January 2011 (has links)
Mercury (Hg) has been recognized as a contaminant of global concern due to its high toxicity, as well as its ability to mobilize over long distances and biomagnify up through the food chain. The discovery of polar springtime atmospheric mercury depletion events (AMDEs) in the 1990s provides a new mechanism for enhanced atmospheric Hg deposition to the surface environment in the Arctic, yet questions remain on the process leading to AMDEs and the net contribution of AMDEs to Hg loadings to the Arctic marine ecosystem. Here we report the first systematic study of AMDEs over the open ocean conducted in the Amundsen Gulf flaw lead system from February to July 2008. A total of 31 AMDEs were observed which showed clear dependence on local sea ice environment and meteorological conditions. Enhanced concentrations of dissolved gaseous mercury were also measured in both under ice and open water conditions. Our results confirm that the sea ice environment plays a large role in Hg dynamics in the Arctic Ocean.
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