Trace Elements in Simultaneously Sampled Aerosol and Snow from the Antarctic Peninsula (Abstract)

Abstract

Ultra-clean techniques have been used to collect a series of fresh surface-snow samples on Gipps Ice Rise, Larsen Ice Shelf (68°48′S, 60°54′W) between 21 December 1984 and 12 February 1985. Aerosol samples were collected simultaneously on to pre-cleaned membrane filters to allow the direct comparison of trace-element levels in air and snow. Samples have been analysed by various techniques for cadmium, copper, lead, zinc, aluminium, calcium, potassium and sodium. For all elements, cross-sample concentration profiles have been obtained to support the data for snow samples. The heavy-metal concentrations found in the surface snow were similar to those measured previously near Gomez Nunatak in the Antarctic Peninsula. The mean aerosol concentrations found at Gipps Ice Rise were Cd: 0.06 pg m−3, Cu: 1.0 pg m−3, Pb; 4.7 pg m−3, Zn: 6.1 pg m−3. These are the lowest concentrations measured so far in Antarctic aerosol. The ratio of the snow concentration (pg g−1) to air concentration (ng m−3), known as the washout factor, has been calculated for each element and sampling period. The data show that, for the Antarctic Peninsula, the marine aerosol is more efficiently removed to the snow-pack than is the crustal aerosol. Heavy metals are least efficiently removed. This result suggests that the measurement of concentrations in snow and ice alone may lead to misinterpretation of atmospheric source strengths.