This article presents the phytosociological characteristics of the São Paulo River estuary, northeastern part of Todosos Santos Bay, a mangrove area with impacts of oil spill as well as the physical-chemical composition of the plant of individuals associated with sediments. For qualitative, phytosociological research, the multiple plot method was applied, with a total of five 20x25 m2 plots. All living species present, Lagunculariaracemosa, Avicenniaschaueriana and Rhizophorae mangle identified with a breast height circumference (HBC) less than 15 cm were marked and their height and circumference values sampled. The results indicated that the mangrove ecosystem of the São Paulo estuary has a fringe face with intermediate size, indicating the species of A. schaueriana as dominant species. The granulate had a predominantly silty texture and low levels of the elements Ba, Co, Cr, Cu, Mn, Ni, Pb, V and Zn that are within the range of variation of this type of environment. Geochemical analysis of sediments reveals significant differences between plots. Diagnostic reasons pointed to a predominantly pyrogenic origin. Therefore, they consider mixed sources of polycyclic aromatic hydrocarbons (PAHs) contaminating this location as a result of the incomplete burning of fossil fuels and the presence of domestic effluents.