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This paper deals with both the transport processes of several classes of organic pollutants in a large area of Victoria Land and Ross Sea (Antarctica) and the role played by marine aerosol which involves the exchange process between the sea surface and the atmosphere. The mechanisms of transfer process from the seawater to the atmosphere and aerosol of three major classes of pollutants (Polycyclic Aromatic Hydrocarbons, PAHs, Polychlorobiphenyls, PCBs, and Organochloride Pesticides, OCPs) were investigated in samples of snow and firn collected during several Italian Expeditions from 1996 to 2014 in a large area of Antarctica. The samples were gathered at different distances from the sea (Rennick Glacier and traverse GV7-Talos Dome-Dome C), at different altitudes (Mt. Melbourne) and at different depths (Evans Nevé). The strategic sampling spots allowed the study of the mechanisms involved in the transfer process that occurs from the seawater to the aerosol and the atmosphere and the consequent diffusion of these pollutants in the environment. Organic compounds linked to sea aerosol showed a fractionation depending on the altitude and on the distance from the sea in agreement with their volatility and affinity to aerosol particles. The results highlighted a decreasing trend of the concentration with the increase of the altitude. This behavior is significant for samples coming from the winter storm, when the very heavy sea produces a high quantity of marine aerosol, where the amount of PCBs, OCPs and PAHs reaches respectively a decrease of 50, 70 and 40% compared to the value found at the lowest altitude. A significant decrease of the concentration of the heavier PAHs and of DDT with the altitude was common in all the samples collected in Mount Melbourne, showing a differentiation in the transportation, and hence in the diffusion, of the analytes on the base of their molecular weight. The dependence of the pollutants on the distance from the sea showed an increase of the contaminant in proximity to the Ross Sea. The samples collected on Evans Nevé and GV7 showed a content of PAHs and DDT 1.5 and 3 times higher on superficial snow than the values found at greater depth. This seems to be connected to a significant flow increase of these pollutants in Antarctica in the last decades. • Organic pollutants long range transport processes. • Role of marine aerosol. • Different POPs behavior with distance from the sea, different altitudes and depths. • Snow and ice samples in Antarctica. [ABSTRACT FROM AUTHOR]

Abstract: A four-century record of fourteen polycyclic aromatic hydrocarbons (PAHs) and seven polychlorobiphenyls (PCBs) was obtained from two snow/firn cores gathered at Talos Dome (Antarctica) in order to assess the contribution of human activities to global environmental pollution. The total concentrations of ΣPAH14 and ΣPCB7 were 0.7ng/l and 0.06ng/l in the deepest firn sample analyzed, and 3.4ng/l and 0.22ng/l in surface snow samples deposited over the last few years, respectively. Our data highlighted the presence of PAH maxima in the concentration depth profile, which correlated with non-sea salt sulphate maxima associated with the major known volcanic eruptions in the period 1600–1930. PAHs showed the highest concentration in the core (4.6ng/l) at a depth of about 27.8m (14.8m water equivalent), here named the “Tambora PAH excess”, in relation to the Tambora eruption (1815A.D.), the largest in recorded history. Surprisingly the data also revealed the presence of synchronous PCB maxima, with a well defined peak (0.14ng/l) at a depth of 27.8m. Between 1930 and 2002, PAHs showed an overall 50% increase, with a slope of about 0.013ngl−1 year−1. This can be predominantly attributed to the emission of incomplete combustion processes of organic matter related to anthropogenic activities. PCBs show a much higher increase (+200%) with a slope of 0.0034ngl−1 year−1 in a very limited period (1930–1980) which is almost totally due to the massive industrial production and use of PCBs, here named “industrial PCB excess”. The slight tendency of PCBs to a constant level from 1980 to 2002 might be attributed to the reduction in the industrial production of PCBs and the restricted use only in totally enclosed systems which started in many countries in the late 1970s. [Copyright &y& Elsevier]