PAHs in soil and surface marine sediment near Jubany station (Antarctica)

This study reports the concentration of PAHs in sediment samples collected in two consecutive summer Antarctic expeditions at Potter Cove and on the peninsula, in the vicinity of Jubany Station (South Shetland Islands). Two- and 3-ring PAHs (methylnaphthalene, fluorene, phenanthrene and anthracene) were the main compounds found in most sites, although total PAH concentrations showed relatively low levels compared with other humanimpacted areas in Antarctica. Pattern distribution of PAHs observed in samples suggested that low-temperature combustion processes such as diesel motor combustion and open-field garbage burning are the main sources of these compounds. The sediment PAH contents were assessed also in relation to the distribution in soils. The highest level in soil was detected in the upper layer of permafrost followed by a sharp decrease in depth, showing this layer is acting as a barrier for downward PAH migration. The authors observed a significant decrease in the soil content in summer 2005 (range 12 ±1 - 153±22 ng g-1) compared to summer 2004 35 (range 162±15 - 1182±113 ng g-1) contemporaneously was observed the accumulation in the marine sediment of the area. The PAH concentrations in surface sediment collected nearby the station increased drastically in 2005 (range: 36±3 - 1908±114 ng g-1) compared to 2004 (range: 28±3 - 312±24 ng g-1). Precipitation regime and water run off suggest that an important wash out of soil-PAHs occurred during the interval time between samplings. Results showed that the present PAH contamination level of Jubany Station was relatively 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 an important soil associated PAH mobilization with unpredictable consequences.