Air-surface exchange measurements of gaseous elemental mercury over naturally enriched and background terrestrial landscapes in Australia
| Autor: | G. C. Edwards, D. A. Howard |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Atmospheric Chemistry and Physics, Vol 13, Iss 10, Pp 5325-5336 (2013) |
| Druh dokumentu: | article |
| ISSN: | 1680-7316 1680-7324 |
| DOI: | 10.5194/acp-13-5325-2013 |
| Popis: | This paper presents the first gaseous elemental mercury (GEM) air-surface exchange measurements obtained over naturally enriched and background (−1 Hg) terrestrial landscapes in Australia. Two pilot field studies were carried out during the Australian autumn and winter periods at a copper-gold-cobalt-arsenic-mercury mineral field near Pulganbar, NSW. GEM fluxes using a dynamic flux chamber approach were measured, along with controlling environmental parameters over three naturally enriched and three background substrates. The enriched sites results showed net emission to the atmosphere and a strong correlation between flux and substrate Hg concentration, with average fluxes ranging from 14 ± 1 ng m−2 h−1 to 113 ± 6 ng m−2 h−1. Measurements at background sites showed both emission and deposition. The average Hg flux from all background sites showed an overall net emission of 0.36 ± 0.06 ng m−2 h−1. Fluxes show strong relationships with temperature, radiation, and substrate parameters. A compensation point of 2.48, representative of bare soils was determined. For periods of deposition, dry deposition velocities ranged from 0.00025 cm s−1 to 0.0083 cm s−1 with an average of 0.0041 ± 0.00018 cm s−1, representing bare soil, nighttime conditions. Comparison of the Australian data to North American data suggests the need for Australian-specific mercury air-surface exchange data representative of Australia's unique climatic conditions, vegetation types, land use patterns and soils. |
| Databáze: | Directory of Open Access Journals |
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