Integrating Ecosystem Services in Historically Polluted Areas: Bioremediation Techniques for Soils Contaminated by Heavy Metals

Bioremediation of soils contaminated by heavy metals is based on the use of specially selected plants able to reduce the hazards of toxic metals. Depending on the mode of action on the heavy metals existing in the soil and the place where the action takes place, the following mechanisms for soil phytoremediation are distinguished: phytostabilization, phytoextraction, phytoimobilization, rhizofiltration, or evapotranspiration. These mechanisms are complex and include the plant ability to reduce the mobility and bioavailability of heavy metals and other pollutants, to extract large amounts of heavy metals from the soil or to evaporate water together with various pollutants already reached in the rhizosphere. Decontamination of polluted soils by using bioaccumulative plants is proposed as an environmental-friendly alternative to the traditional physicochemical methods, being a sustainable method with a great potential in the terms of environmental protection and cost management.