Polycyclic aromatic hydrocarbons in superficial coastal sediments from Bizerte Lagoon, Tunisia

摘要

Polycyclic aromatic hydrocarbons PAHs are widespread environmental contaminants, derived from anthropogenic or natural sources. They are formed as a consequence of incomplete combustion of organic matter (e.g., from fossils fuels) and are also components of crude oil and its refined products. Natural sources of PAHs include forest-fires and post-depositional transformation of biogenic precursors (Young and Cerniglia, 1995). Environmental concerns regarding PAHs are due to their potential to form highly carcinogenic and muta-genic derivatives such as diols and epoxides (Braid, 1995; Stegeman and Lech, 1991). PAHs reach the marine environment via such sources as effluent discharges, urban run-off, atmospheric transport, and agricultural runoff. Because of their low water solubility and their hydrophobicity, PAHs in the aquatic environment rapidly become associated with inorganic and organic suspended particles (Gearing et al., 1980; Chiou et al., 1998) and subsequent deposition in sediment. Therefore, coastal sediments are known as temporary or long term sinks for PAHs and can be used to monitor PAH inputs to the aquatic environment. The importance of sediments as reservoirs for PAHs is well-documented (Prahl et al., 1984; Maher and Aislabie, 1992; Nes and Oug, 1997).