Strategies of Bioremediation for the Degradation of Petroleum Hydrocarbons in the Presence of Metals in Mangrove Simulated

Contamination by oil spills in coastal ecosystems, especially in mangrove zones, has been common in countries with oil industry. The aim of this study was, therefore, to evaluate the efficiency of application of the two models developed for pilot-scale remediation, intrinsic bioremediation (indigenous microorganisms), and phytoremediation (Avicennia schaueriana). The degradation of hydrocarbons was determined by gas chromatography (GS) with flame ionization detector. The metals Al, Fe, Pb, Cr, Cu, Zn, and Ni were determined by flame atomic absorption spectrometry in the mangrove simulated with sediment of Todos os Santos Bay, Brazil. These models also monitor other biogeochemical parameters (nitrogen, phosphorus, total organic carbon, pH, redox potentioal, dissolved oxygen, salinity, temperature, bacterial density). The integrated assessment of data showed that both techniques were effective in degrading organic compounds from oil but that phytoremediation is the most efficient (89% removal). The intrinsic bioremediation model has no direct correlation with metal concentrations, but a positive correlation with Al and Ni was found in the hydrocarbon removal by phytoremediation. Avicennia schaueriana represents efficiency in phytoextraction and phytostimulation. The results suggest that the phytoremediation model, through its various mechanisms, may become a technique for the removal of petroleum hydrocarbons in the presence of metals in mangrove ecosystems near industrial areas.