title: Atmospheric pollutants in fog and rain events at the northwestern mountains of the Iberian Peninsula.
abstract: Atmospheric polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) and exist in gas and particle phases, as well as dissolved or suspended in precipitation (fog or rain). While the hydrosphere is the main reservoir for PAHs, the atmosphere serves as the primary route for global transport of PCBs. In this study, fog and rain samples were collected during fourteen events from September 2011 to April 2012 in the Xistral Mountains, a remote range in the NW Iberian Peninsula. PAH compounds [especially of low molecular weight (LMW)] were universally found, but mainly in the fog-water samples. The total PAH concentration in fog-water ranged from non-detected to 216 ng·L(-1) (mean of 45 ng·L(-1)), and was much higher in fall than in winter. Total PAH levels in the rain and fog events varied from non-detected to 1272 and 33 ng·L(-1) for, respectively, LMW and high molecular weight (HMW) PAHs. Diagnostic ratio analysis (LMW PAHs/HMW PAHs) suggested that petroleum combustion was the dominant contributor to PAHs in the area. Total PCB levels in the rain and fog events varied from non-detected to 305 and 91 ng·L(-1) for, respectively, PCBs with 2-3 Cl atoms and 5-10 Cl atoms. PCBs, especially those with 5-10 Cl atoms, were found linked to rain events. The occurrence of the most volatile PCBs, PCBs with 2-3 Cl atoms, is related to wind transport from far away sources, whereas the occurrence of PCBs with 5-10 Cl atoms seems to be related with the increase of its deposition during rainfall at the end of summer and fall. The movement of this fraction of PCBs is facilitated by its binding to air-suspended particles, whose concentrations usually show an increase as the result of a prolonged period of drought in summer.
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Fernández-González
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain.
authors.forename: Iria
authors.initials: I
authors.lastname: Yebra-Pimentel
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Martínez-Carballo
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain. Electronic address: jsimal@uvigo.es.
authors.forename: Jesús
authors.initials: J
authors.lastname: Simal-Gándara
authors.affiliation: Soil Science and Agricultural Chemistry Department, Faculty of Biology, University of Santiago de Compostela, Santiago Campus, E15782 Santiago de Compostela, Spain. Electronic address: xabier.pombal@usc.es.
authors.forename: Xabier
authors.initials: X
authors.lastname: Pontevedra-Pombal
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere; D004784:Environmental Monitoring; D011078:Polychlorinated Biphenyls / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D011891:Rain / Q000737:chemistry; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis; D014887:Weather
chemical_list: D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Atmospheric pollution; Fog; Grasshopper effect; PAHs; PCBs; Rain