Atmospheric PCB Concentration at Terra Nova Bay, Antarctica

This study increases the limited atmospheric database on PCB in remote areas by reporting PCB concentrations during the austral summer (2003-2004) at a site in Terra Nova Bay, Antarctica and hypothesizing their possible sources. PCBs were present in the atmosphere essentially bound to aerosols <1 μm, and the gas-phase concentration of individual PCB congeners in the air of Terra Nova Bay ranged from below the LOD to 0.25 pg m-3. The concentrations found were extremely low and confirm the still pristine characteristics of the Antarctic environment, even with respect to the values found in anthropized regions. The highest concentrations, of about 100 fg m-3, were observed for PCB2, PCB3 and PCB28+31 whereas the lowest concentrations, of few fg m-3, were 30 observed for PCB34, PCB46+39, PCB67, PCB63, PCB77 and PCB85. Over 90% of the total PCB content was due to congener with one to four chlorine atoms and only about 10% with five to seven chlorines, whereas higher chlorinated PCBs were below detection limits. These results were in agreement with those reported in 2003. There is evidence that other organic compounds may represent future emerging pollutants in polar regions. In particular, it must be noted that presence of PCNs, discussed above, and nitro-PAHs determined in pristine environments suggest that future monitoring actions must be taken for these classes of pollutants in polar regions.
Indeed, the origin of Antarctic nitro-PAHs remains uncertain: while the abundance ratio of the nitro-naphtalene isomers supported the hypothesis of local direct emission, the relative high abundance of dinitro- with respect to mononitro-derivatives suggested that an efficient gas-phase nitration may take place on a substrate possibly transported from other continents. In addition to atmospheric transport, local sources of PCB such as Antarctic Research Stations should be considered. The impact of scientific bases and related activities on the environment are more efficiently recorded by sediment analysis.