Distribution and Origin of Aliphatic Hydrocarbons in Surface Sediments of Strategical Areas of the Western Moroccan Mediterranean Sea

This work focuses on the assessment of aliphatic hydrocarbons in sediments collected from the western Moroccan Mediterranean coasts. Two zones have been chosen for this study. Zone 1 corresponds to Tangier's bay and zone 2 corresponding to the fringe between Kabila and Kaâ Srass. The aliphatic hydrocarbons were extracted and analysed using chromatographic techniques (GC/FID and GC/MS). The results showed a more important accumulation of aliphatic hydrocarbons in Tangier's bay if compared with zone 2. Levels ranged within 128.8 to 340.31 µg/g dry weight, with two exceptions 611.72 and 648.16 µg/g dry weights and from 5.25 to 22.71 µg/g dry weights, for zones 1 and 2, respectively. Moreover, the aliphatic hydrocarbons distribution proves to be strongly influenced by the nearness to input sources and by oceanographic and hydrodynamic conditions. Thus, two distribution patterns were observed corresponding to the two areas studied. Furthermore, the examination of origin fingerprinting criteria proved the biogenic origin related to phytoplankton, bacteria and continental plant waves. The anthropogenic character of hydrocarbons was also evidenced especially in Tangier's bay, by several chromatographic criteria and was confirmed by the presence of hopanes with predominant C29 and C30 α, β compounds.