Examining and introducing plant species in the process of soil refining of lands contaminated with heavy metals by irrigation with gray watersr

The purpose of this study is to investigate the potential of some plants for Phytoremediation of soil contaminated with lead, zinc, cadmium and copper. To do this, four plant species of Achillea millefolium, Agropyron elongatum, Bouteloua dactyloides and Artemisia sieberi were cultivated and plant samples were irrigated with refinery wastewater. The results showed that in terms of plants, Bouteloua dactyloides, Artemisia sieberi and Achillea millefolium are good transfer of metals to their aerial parts which is suitable for plant extraction (the most important technique of Phytoremediation). Agropyron elongatum mostly accumulates copper and lead metals in the root. This is a proper feature of phytostabilization. Also the capability of these four plants species for Phytoremediation is as follows: Bouteloua dactyloides> of Achillea millefolium> Artemisia sieberi = Agropyron elongatum. Bouteloua dactyloides is proper for Phytoremediation of all heavy metals. For Bouteloua dactyloides, plant transfer factor (TF) in metals: zinc, copper, lead and cadmium is 1.17 and 1.9, 1.12 and 1.41, respectively, and bio concentration factor (BCF) for that in these metals are 1.77 and 1.22, 0.95 and 1.37, respectively. Since Bouteloua dactyloides has high tolerance to drought and high temperatures and is also suitable for lawn making, it is suggested that this type of species is used for Phytoremediation of soils contaminated with heavy metals in polluted areas as well as lawn making so that in addition to soil cleansing from heavy metals and being proper with native climates in many parts of Iran and having low irrigation requirements.