Distribution and Origin of Hydrocarbons in Water and Sediment in São Sebastião, SP, Brazil

This study describes the dissolved/dispersed petroleum hydrocarbons (DDPH) in surface water and the origin and distribution of aliphatic and aromatic hydrocarbons in samples from the surface bottom sediments. The main objective was to verify the anthropogenic contribution on the adjacent inner shelf off São Sebastião, taking into account the distribution of hydrographic properties and knowledge of the main circulation. The DDPH concentration range of the 20 samples was from 0.35 to 2.50 μg.L−1, characterizing this region as slightly affected by the contribution of petroleum hydrocarbons. Considering sediment hydrocarbon results, sites located in the inner shelf were divided into three groups: one with mainly biogenic hydrocarbons, a second one with biogenic and petroleum hydrocarbons and a third with significant contribution of petroleum hydrocarbons. These results show an influence of human activities in the São Sebastiõ Channel on the surrounding area of the inner shelf.