Origin and distribution of hydrocarbons and organic matter in the surficial sediments of the Sfax-Kerkennah channel (Tunisia, Southern Mediterranean Sea)

International audienceWe investigated the origin and distribution of aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs)and organic matter (OM) in surficial sediments of the Sfax-Kerkennah channel in the Gulf of Gabès (Tunisia,Southern Mediterranean Sea). TOC, AH and PAH concentrations ranged 2.3–11.7%, 8–174 μg g−1 sed. dw and175–10,769 ng g−1 sed. dw, respectively. The lowest concentrations were recorded in the channel (mediumsand sediment) and the highest ones in the Sfax harbor (very fine sand sediment). AHs, PAHs and TOC werenot correlated for most of the stations. TOC/N and δ13C values revealed a mixed origin of OM with both marineand terrestrial sources. Hydrocarbon molecular composition highlighted the dominance of petrogenic AHs andthe presence of both petrogenic and pyrogenic PAHs, associated with petroleum products and combustion processes.This work underscores the complex distribution patterns and the multiple sources of OM and hydrocarbonsin this highly anthropogenized coastal environment