Influence of sediment parameters on the distribution and fate of PAHs in an estuarine tropical region located in the Brazilian semi-arid (Jaguaribe River, Ceara coast)

18 polycyclic aromatic hydrocarbons (PAHs) were evaluated in the Jaguaribe River to explore the influence of grain size, organic carbon, humic and fulvic acids and black carbon on their adsorption onto sediment. The Sigma PAHs concentrations variated from 0.6 to 3752.0 ng g(-1) with highest concentrations in the estuarine zone. The PAHs predominant source along the river was from mixed sources, mainly related to biomass combustion, small oil spills related to recreational nautical activities and runoff from cities. Organic and inorganic parameters presented influence on PAHs distribution along the river, with humic acid as a determinant factor. These research findings are of importance to an assessment of the fate and transport of PAHs in estuarine systems.