Evaluation of Airborne Organic Pollutants in a Pyrenean Glacial Lake (The Sabocos Tarn)

Mountain lakes are excellent indicators for airborne organic pollutant transport and accumulation studies. However, very few studies have been focused on lake water mass. Also, there is a lack of studies performed after 2004-2009 period when the enforcement of most international organic pollutant banning policies (e.g., The Stockholm convention) occurred. We report concentration of 66 different semi-volatile organic compounds (SOCs) in the Sabocos tarn water mass (a Spanish Pyrenees cirque glacial lake) from 2011 to 2014. Analyzed SOCs include compounds of current and past use with different sources (i.e., current and historic-use pesticides, industrial and urban-use compounds, and combustion by-products) and chemical properties (i.e., volatility, water solubility, and persistence in the environment). Most banned chemicals such as dichlorodiphenyl trichloroetanes (DDTs), aldrins, most polybromodiphenyl ether (PBDE) congeners, endosulfans, triazine, and simazine were detected in consistently low concentrations. In contrast, chemicals still in use such as BDE-209, terbutilazine, diuron, metolachlor, and chlorpyrifos were found in higher and more variable amounts. Polychlorobiphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were high as compared to previous studies in other Pyrenean and European lakes suggesting airborne pollution from nearby anthropogenic sources. Overall, levels of hexacyclohexanes (HCHs) during most of the sampling period were low according to other studies in similar environments. However, the Sabocos water mass recorded a concentration peak of some HCH isomers in summer 2014 related with the HCH residues transfer operation at the nearby (20 km) BailIn landfill site (Sabinanigo, Spain).