Relationship between hydrocarbons and bacterial activity in mediterranean sediments: Part 1—nature and concentration of the hydrocarbons in the sediments

Abstract

The presence of hydrocarbons in marine sediments of the Mediterranean coast was studied by two different but complementary methods. Results obtained through a technique especially adapted to sediments are given; this leads to a relatively accurate and reproducible determination of the hydrocarbon concentrations in sediments collected at many sites of the Mediterranean coast, polluted or not, by chronic petroleum input (Brusc lagoon, zones of Embiez, Fos, Carry-le-Rouet and Etang de Berre). The hydrocarbon concentrations in the non-polluted sediments are always less than 300mg/kg of dry sediment, with important variations according to season. In the polluted sediments the hydrocarbon concentrations are more than 300ppm, with variations difficult to interpret. The analytical profile of these hydrocarbons shows considerable differences from that for the hydrocarbon fraction extracted from the non-polluted sediments. These differences principally relate to concentrations of odd and even carbon numbered hydrocarbons and the presence of aromatic or polyaromatic compounds specific of petroleum fractions.