Polycyclic aromatic hydrocarbon deposition on the ice sheet of Greenland. Part I: superficial snow

Abstract

After a long-range transport in the air, atmospheric chemical substances of anthropic or natural origin are deposited on the Greenland surface mainly during snowfall episodes. The surface snow conserves the geochemical imprint of these compounds, especially when they are unreactive. As part of the TAGGSI program, carried out in Greenland from 1993 to 1996, the deposition and the transfer of polycyclic aromatic hydrocarbons, from atmosphere to ice sheet, was studied by determining the concentrations of these species in a 5 m depth snow pit and in a 75 m depth ice core. This first part concerns the snow samples collected in the snow pit. With a sampling step of 5 cm, the seasonal and interannual variation of the deposits was determined. The snow strata were dated on the basis of the calcium deposits, which are particularly high during Arctic haze. Correlations with carbon, ammonium, and sulphates are performed. The good quality of the correlations shows the coincidence of the deposits of chemical substances presumed to be of the same origin: total PAH and black carbon; (pyrene+fluoranthene) and sulphates; retene and ammonium.