Distribution of polycyclic aromatic hydrocarbons in soil and surface marine sediment near Jubany Station (Antarctica). The permafrost as a low-permeability barrier

CURTOSI, A., RUBERTO L., VODOPIVEZ, C., PELLETIER E., MAC CORMACK, W.P

Malasia

Congreso; 3rd Malaysian International Seminar on Antarctica. Malasia; 2007

Universiti Malaysia Sabah, the Academy of Sciences Malaysia (ASM), International Council for Science (ICSU)-SCAR, Universiti of Malaya and the Ministry of Science, Technology & Innovation

Human activities represent the main sources of polycyclic aromatic hydrocarbons (PHAs). In Antarctica, scientific stations, fisheries and tourism activity caused local pollution events including PAHs contamination. In Antarctica, environmental factors as low temperatures and low nutrient availability significantly reduce activity of naturally-occurring PAHs-degrading microorganisms and contribute to their accumulation. In this work surface sediments and soils at different depths were sampled in two consecutive summer Antarctic expeditions in the vicinity of Jubany station (62˚14’S, 58˚40’W). PAHs with low and medium molecular weight were predominant. Pattern of compounds suggested that low temperature combustion processes are the main source pollution. PAHs concentration increased from surface to depth into the active layer. The highest concentrations were detected in the permafrost table followed by a sharp decrease in depth. This fact suggests that permafrost is acting as a barrier for downward PAHs migration. PAHs level in soils from both sampling programs showed a significant decrease (p<0.01) in 2005 (range at 75 cm-depth: 12 ± 1 – 153 ± 22 ng/g) compared with 2004 (range at 75 cm-depth: 162 ± 15 – 1182 ± 113 ng/g). PAHs in surface sediment increased drastically in 2005 (range: 36 ± 3 – 1908 ± 114 ng/g) compared with 2004 (range: 28 ± 3 – 312 ± 24 ng/g). Precipitation regime and water run off suggest that an important wash out of soil PAHs occurred between samplings. Results showed that PAHs contamination in Jubany station is low compared to other reported cases in Antarctica but also suggests that an increase in rain and in thawing processes caused by the global warming could result in a soil-associated PAHs mobilization with unpredictable consequences for the biota of Potter Cove.