ALIPHATIC AND POLYCYCLIC AROMATIC-HYDROCARBONS AND SULFUR OXYGEN DERIVATIVES IN NORTHWESTERN MEDITERRANEAN SEDIMENTS - SPATIAL AND TEMPORALVARIABILITY, FLUXES, AND BUDGETS/

The spatial and temporal distribution of aliphatic and polycyclic arom atic hydrocarbons (PAHs) and sulfur/oxygen derivatives in sediments fr om the NW Mediterranean basin were investigated. Along the Continental Shelf and slope, an unresolved complex mixture (UCM) of aliphatic hyd rocarbons and alkylated PAHs, indicative of petrogenic inputs, were pr edominant. Long-chain n-alkanes derived from terrestrial plant waxes ( n-C-27, n-C-29, and n-C-31) and parent PAHs, which are typical of high -temperature combustion processes, were evenly distributed in the whol e basin and largely prevailing in the deepest areas. Perylene, a geoch emically derived PAH, was found highly abundant in the areas influence d by river discharges. The highest anthropogenic hydrocarbon inputs we re found near the cities of Marseille and Barcelona, being the contrib ution of the Rhone River ca. 25 times higher than that of the Ebro. Fl uxes of PAHs in the deep basin were consistent with a predominant atmo spheric input. These results account for an accumulation rate in the N W Mediterranean sediments of 2700 t/year of petrogenic unresolved hydr ocarbons (UCM) and 60 t/year of pyrolytic PAHs. Analyses of dated sedi ment cores from the Rhone and Ebro prodeltas exhibited maximum accumul ation rates of PAHs in the 1920-1940 and the 1975-1990 periods, althou gh with a steep decrease since 1985 in the Rhone area.