Atmos. Chem. Phys. Discuss., 13, 18779-18808, 2013
www.atmos-chem-phys-discuss.net/13/18779/2013/
doi:10.5194/acpd-13-18779-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Factors affecting the atmospheric occurrence and deposition of polychlorinated biphenyls in the Southern Ocean
C. J. Galbán-Malagón1, S. Del Vento1,2, A. Cabrerizo1,*, and J. Dachs1
1Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18–26, Barcelona, 08034, Catalunya, Spain
2Lancaster Environmental Centre, Lancaster University, Lancaster, LA1 4YQ, UK
*now at: Institute for Environment and Sustainability, European Commission, Via Enrico Fermi 2749, 21027, Ispra, Italy

Abstract. Persistent organic pollutants, such as polychlorinated biphenyls, reach the Southern Ocean atmosphere through long-range atmospheric transport. In this study we report the largest data set available for the atmospheric occurrence of PCBs in the Southern Ocean surrounding the Antarctic Peninsula from samples obtained during three cruises in 2005, 2008 and 2009. The gas phase concentrations of total PCBs (σ25PCBs) ranged from 1 to 70 pg m-3, while the aerosol phase concentrations were significantly lower (0.04 to 0.4 pg m-3). The aerosol phase is enriched in the more hydrophobic congeners consistent with the model predictions of gas-particle partitioning. There is a net air to water diffusive flux of PCBs to the Southern Ocean, up to 50 times higher than the dry deposition flux of aerosol-bound PCBs. The air–water disequilibrium is higher for the more hydrophobic congeners consistent with the role of the biological pump removing PCBs from the water column by settling of PCBs bound to organic matter. The atmospheric half-lives of PCB 52 and 180 are of 3.8 and 1 days, respectively, as predicted from the measured atmospheric concentration and depositional fluxes. The volatilization of PCBs from Antarctic soils during the Austral summer drives higher gas phase concentrations in the atmosphere over Antarctica during the warmer periods. This temperature dependence is not observed for PCBs over the adjacent Southern Ocean, probably due to the importance of long-range atmospheric transport and atmospheric deposition modulating the atmospheric occurrence of PCBs.

Citation: Galbán-Malagón, C. J., Del Vento, S., Cabrerizo, A., and Dachs, J.: Factors affecting the atmospheric occurrence and deposition of polychlorinated biphenyls in the Southern Ocean, Atmos. Chem. Phys. Discuss., 13, 18779-18808, doi:10.5194/acpd-13-18779-2013, 2013.
 
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