PCB-11 in Antarctic lakes and snow

Antarctica is usually considered a pristine ecosystem, nevertheless it is influenced by persistent organic pollution, mainly due to a cold-trapping process driven by the long range atmospheric transport. Polychlorinated Biphenyls (PCBs) were detected in the Antarctic environment since decades ago. In the last few years there has been an increasing interest about the congener 3,3’-dichlorobiphenyl (PCB-11). This was almost absent in original Aroclor mixtures but it largely derives from consumer goods containing azo- and phthalocyanine pigments. Recently it has been found as a contaminant in various environments worldwide [1] and even in Antarctica [2, and ref. therein], where it represented one of the most abundant congeners. In this work we focus on the determination of PCB-11 in lake water and superficial snow samples collected in Northern Victoria Land during the 27th Italian Antarctic Expedition (austral summer 2011– 2012). Six summer ice-free lakes near Terra Nova Bay (Carezza, Edmonson Point 15A, Edmonson Point 14, Tarn Flat 20, Inexpressible island 10B, Gondwana) were investigated, together with five snow-covered sites (David Glacier, Vegetation Island, Mid Point, ITASE GV5, Campo Faraglione) ranging from coastal areas to East Antarctic plateau. Samples were collected in pre-cleaned airtight stainless steel containers, allowed to melt and continuous liquid-liquid extracted at the Mario Zucchelli Station in Antarctica. Afterwards extracts were purified onto a disposable neutral silica column with an automated system (PowerPrepTM, FMS) and analysed by HRGC-HRMS (HP 6890 - MAT 95XP Thermo Finnigan). Quantification was performed using internal standards and isotope dilution technique. Results were corrected using procedural blanks. PCB-11 was detected in all the samples, with comparable levels in each lake (few pgL-1); slightly higher values were found in snow samples, maybe because of the larger surface area. Funds were provided by PNRA 2009/A2.10.