Sediment trap fluxes of polycyclic aromatic hydrocarbons in the Mediterranean Sea

Abstract

Fluxes of polycyclic aromatic hydrocarbons (PAHs) were measured in the Ligurian Sea (northwestern Mediterranean Sea) in sediment trap experiments, from the Dyfamed operation (France/JGOFS program). PAH fluxes, from 0.30 to 0.91 μg m −2 d −1, were compared to those calculated from PAH concentrations in zooplankton fecal pellets collected in the same area and in Mediterranean surface sediments. The distribution of PAH and ratio of specific compound in sediment traps suggested that the PAH mixture has a predominantly pyrolytic origin from anthropic combustion processes. Phenanthrene, fluoranthene and pyrene were generally the major compounds in both sediment traps and fecal pellets. The transport pathways for these PAHs were different than for the higher molecular weight compounds (compounds with more than 4 rings). The low molecular weight PAH fluxes were larger in the water column than in surface sediment; fluxes for the higher molecular weight compounds were similar in both compartments. The difference in fluxes is discussed in terms of composition, transport and recycling of PAHs in different reservoirs.