Heavy metals are the most serious environmental pollutants in the current time as a result of industrial development in several countries. Their pollution is poisoning threat for human, animal and plant life because toxic metals cause several serious ailments. Many techniques have been emerged for the elimination of heavy metal contamination for the environment. Either physical or chemical ones, have limitations such as high cost, long time, logistical problems and mechanical complexity. Phytoremediation alternative solution can be used for heavy metal remediation process because of its advantages as a cost-effective, efficient, and eco-friendly technology based on the use of metal-accumulating plants. Many plant species have a high potential as heavy metals bioaccumulators and can be used for their phytoremediation process. This review focus on the common phytoremediation mechanisms and the role of four street-tree species (Moringa oleifera, Azadirachta indica, Lantana camara and Conocarpus erectus) commonly cultivated throughout the Kingdom of Saudi Arabia (KSA) in phytoremediating various pollutants. Trees description, habitat of growth and their potential to phytoremediate different heavy metals would be discussed.
Phytoremediation;pollution;street trees;heavy metals