While soils of Estarreja continue to be important sinks of persistent contaminants, existing remediation techniques are often ineffective and fail when addressing multiple contaminants. Biochar – biomass pyrolysed for enhancing carbon sequestration and other biomass productivity – presents a dual potential for improving soil decontamination: its high porosity can both promote adsorption of contaminants and provide habitat conditions for microbial development. It is hypothesized that the microbiomes existing in contaminated soils present enhanced abilities to thrive under such adverse environments, thus allowing for a natural improvement of the ecosystem services provided by the soil. This research aims at a novel technique for remediating soil contamination, combining the use of biochar and mixed microbial cultures taken from those “dirty” soils identified in Estarreja and further stimulated to oxidize both organic and inorganic contaminants.