Phytostabilisation
Phytostabilisation involves the reduction of the mobility of heavy metals in soil through immobilisation, which can be accomplished by decreasing wind-blown dust, minimising soil erosion, and reducing contaminant solubility or bioavailability to the food chain University of Hawaii. Unlike phytoextraction, the objective is not to remove contaminants but to immobilise them in place. The mobility of contaminants is reduced by the accumulation of contaminants by plant roots, absorption onto roots, or precipitation within the root zone University of Hawaii.
Plant roots stabilise heavy metals, ultimately reducing their mobility and bioavailability, and established vegetation cover on degraded soil surfaces effectively mitigates soil erosion ResearchGate. In some cases, plants can excrete substances that produce chemical reactions, converting heavy metal pollutants into less toxic forms Wikipedia. The advantages of phytostabilisation include effective rapid immobilisation and no need for biomass disposal, though the major disadvantage is that pollutants remain in the soil or root system, generally in the rhizosphere Nature.
Enhanced results can often be achieved through "aided phytostabilisation", where soil amendments such as organic matter, phosphates, alkalising agents, and biosolids are added to decrease solubility of metals University of Hawaii. The technique has proved useful for treatment of Pb, As, Cd, Cr, Cu, and Zn contaminated soils Nature, and is particularly attractive when other methods to remediate large-scale areas having low contamination are not feasible University of Hawaii. Suitable plant species include grasses such as Festuca rubra (red fescue), Miscanthus × giganteus, and other metal-tolerant species that accumulate metals primarily in roots rather than shoots.