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3. Material and methods
3.1. Sampling
Sediment cores were collected in the Gulf of Lions during the MATER HFF experiment and the REMORA3 oceanographic cruise (2002) and stretch over the entire shelf and slope/canyons regions (Fig. 1; Table 1). For comparison purposes we also studied a Amyloid Beta-peptide (1-40) sample taken in an open western Mediterranean Sea location, collected during the ADIOS cruise (2001). The investigated samples correspond to the first half-centimeter of the cores. Sediment cores were sub-sampled upon recovery on board and kept frozen until analyses in the laboratory.
3.2. Analysis
4. Results
4.1. PAH composition
A total of 21 PAH were identified and quantified, encompassing a series of parent (unsubstituted) PAH with 3–7 aromatic rings (fluorene to coronene) and several alkyl-substituted homologues. An average PAH molecular profile is shown in Fig. 2. Overall, a large proportion of the sediment PAH load arises from 3- and 4-ring compounds (both parent and alkylated phenanthrenes and pyrene/fluoranthenes), with lesser contribution from 5-ring PAH. In general, PAH distribution usually maximizes at the dimethylphenanthrenes (C2-Phe) or methylpyrenes (C1-Pyr). In some cases (close to the Rh?ne River mouth or at the upper/lower slope and the deep basin), the relative abundance of PAH with > 4 rings is increased, and benzofluoranthenes (BFlths) are the most abundant PAH.