Some Evidence of Long-Distance Transport, Local Sources and Fractionation Between Air and Snow for Metallic Aerosols Deposited in Antarctic Snows Since the 1880s (Abstract only)
Using instrumental neutron activation analysis, we have determined the concentrations of Na, CI, Al, Sc, V, Cr, Mn, Co, Fe, Zn, As, Se, Br, Sb, and J in ultra-clean dated snow samples collected in central East Antarctica. These samples had been previously analysed by flameless atomic absorption spectrometry (Boutron 1980). For the elements determined by both techniques (Na, Al, Mn, Fe, and Zn) the results are in remarkable agreement. These new data confirm and extend the conclusion that background concentrations of trace elements observed at present in Antarctic snow are close to those observed about 100 a BP and thus that Antarctic aerosol is still little affected by global atmospheric pollution. These data also confirm that, for several metals, episodes of anomalously high concentrations are in phase with increased sulphate and acidity, which could result from volcanic fallout. However, during such episodes, a straightforward relationship between the rate of increase in trace metals and the rate of increase in sulphate and acidity is not observed. This also affects volatile elements such as Cl, Br, Se, and I. This is probably due to a combined effect of local versus long-range transport of volcanic aerosols together with a physico-chemical segregation between the various components of this aerosol.