PAHs distribution in soil and sediments from the surroundings of an Antarctic Station”

CURTOSI A, RUBERTO L, VODOPIDEZ C, MAC CORMACK WP, PELLETIER E

Punta Arenas, Chile

Congreso; International Congress Poles Apart: Nurturing Global Environmental Aspects (PANGEA); 2006

Universidad de Magallanes, Chile

PAHs are produced by incomplete combustion associated with human activities. Despite Antarctica is a pristine region, human activities caused local but significant PAHs contamination. PAHs accumulate it in the food chain determining the deleterious effect caused on the biota by the release of low quantities of PAHs into the environment. Low temperatures reduce PAHs biodegradation and could contribute to the accumulation of PAHs. Jubany station located at (62˚14’S,58˚40’W) 25 de Mayo Island (King George Island) has permanent human activity. In this work, levels of 16 PAHs considered as priority pollutants (USEPA) and several of their derivatives were determined at five different depths in soil. Analysis included surface sediments obtained from several areas from Potter Cove. Nine sites were sampled during the 2004/05 summer at 0, 75, 100, 150 and 200 cm depth of the soil active layer. In addition, 0, 20, 30 and 60 cm depth samples from permafrost layer were analysed. PAHs concentration was evaluated by GC-MS. PAHs concentration in soil samples increased from surface to the deepest layers. Total PAHs concentration in soils ranged between 12.59-535.00 ng g-1. Phenanthrene represented about 90% of the total PAHs. PAHs concentrations observed in surface sediments showed a high human impact. Higher levels of PAHs (1921.11 ng/g) were observed in the inner Cove, reflecting the influence of the water circulation pattern. Levels of PAHs in permafrost were high in the upper level. Distribution pattern of PAHs observed suggest that the most hydrophilic compounds migrate from surface and accumulate at depths near the permafrost which seems to act as a low-permeability region of the soil. If this hypothesis is confirmed, the melting of permafrost produced by the global warming could determine the leaching and release of a great amount of PAHs in the sea, causing a dramatic alteration of the Potter Cove ecosystem.