Polycyclic aromatic hydrocarbons in seasonal snowcover
The chemical composition of snow can under some circumstances, be used as a monitoring tool for the estimation of atmospheric contamination. Snowfall is often the most important hydrological event in many parts of the world. Polycyclic aromatic hydrocarbons are an important and wide-spread class of...
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| Format: | Thesis |
| Language: | English |
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University of Southampton
1992
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| Online Access: | https://eprints.soton.ac.uk/461233/ https://eprints.soton.ac.uk/461233/1/349496.pdf |
| Summary: | The chemical composition of snow can under some circumstances, be used as a monitoring tool for the estimation of atmospheric contamination. Snowfall is often the most important hydrological event in many parts of the world. Polycyclic aromatic hydrocarbons are an important and wide-spread class of environmental contaminants. Many of them have been demonstrated to have toxic and/or carcinogenic properties. PAHs are prevalent in the atmosphere at trace-levels, and therefore can be expected to be incorporated in snowfall. A sampling methodology and analytical protocol was devised to measure trace-level PAHs in snow. Samples of snow were collected from three contrasting locations: i) a remote, sub-arctic, mountain catchment in the Cairngorm Mountains of Scotland, ii) a remote boreal forest site in the Laurentian Mountains of Canada, and iii) urban and rural sites in Southern England. The samples were analysed by high performance liquid chromatography and gas chromatogrpahy with mass spectrometry detection for a maximum of 18 PAH compounds in both the dissolved and the particulate phases. Total PAH concentrations found in aged snowpack in Scotland are high (max. 3500 ng/1). This is typical of the PAH content of snow in urban regions, and is consistant with results form previous studies of snow from the same location which show elevated concentrations of trace-metals, owing to the long-range transport of contaminants from source regions. Fresh snow had lower PAH values (c. 200 ng/1), more representative of snow from remote areas. A possible positive correlation between snow acidity and PAH content was observed, and there are indications that this may be a source specific relationship. Snow from an urban site in Southampton, U.K. had a very high PAH content (6800 ng/1). Dissolved phase PAHs in snow from Canada had low concentrations of PAHs (1.0 - 240 ng/1). Particulate phase PAHs were not determined, owing to analytical difficulties. The results, whilst limited in extent, represent an important contribution to the ... |
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