Recent research progress in geochemical properties and restoration of heavy metals in contaminated soil by phytoremediation

Heavy metals are widely distributed contaminants in natural environments and their potential threats to human health have attracted worldwide concerns due to the food chain. Therefore, great efforts have been made to reduce them to a safe level in soil. Compared with the traditional methods, the method using plants to remove them has been accepted as a feasible and efficient way. Herein, the geochemical behavior of heavy metals and the restoration methods with phytoremediation were reviewed. In addition, issues on heavy metal speciation as well as its influencing factors, phytoremediation mechanism, phytoremediation effect and vegetation selection principle used for phytoremediation were discussed.