PAHs in the Ría de Arousa (NW Spain): A consideration of PAHs sources and abundance.

Analysis of 35 parental and alkylated homologues of PAHs (Polycyclic Aromatic Hydrocarbons) was carried out in eleven marine sediment samples collected along a central transect in the biggest Galician ría. The samples were collected using a box-core dredge and, after freeze-drying, were kept frozen until analysis. The sediments were extracted by PLE (Pressurized Liquid Extraction) procedure and the quantification of PAHs was performed using gas chromatography coupled to mass spectrometry (GC-MS) with the aid of deuterated PAH internal standards. The total concentration of studied PAHs (Σ35PAHs) ranged from 44.8 to 7901ngg(-1) dry weight (d.w.). The highest PAH concentrations were found in sediments collected near the harbour (7901ngg(-1)) and the cleanest positions were located in the outer zone of the ría. To date, these results are the first data presented in the area so they could be used for regular monitoring and control of future pollution episodes.