Abstract
This study aimed to assess the accumulation content of toxic heavy metals such as Cd, Zn, Cu, Ni and Pb in the soil, shoots and roots of six plants species collected from the second industrial zone of Riyadh, Saudi Arabia. Translocation factor (TF), biological concentration factor (BCF) and bioaccumulation coefficient (BAC) parameters were used to evaluate the of phytoremediation potential of the six studied plants named Malva parviflora, Datura stramonium, Citrullus colocynthis, Rhazya stricta, Phragmites australis and Lycium shawii. Metal concentrations of Cd, Zn, Cu, Ni, and Pb in soils collected from industrial region varied between 19.79, 217, 332, 37.12and 169.8 mg/kg. The pattern of metal accumulation in studied plants were: Zn> Cu> Pb> Ni> Cd. Results obtained showed significant (P >= 0.05) accumulation in the above ground components of Malva parviflora, Rhazya stricta, Phragmites australis and Lycium shawii compared with root. However, the highest accumulation of Cd and Pb was observed in Phragmites australis and followed by Lycium shawii. The translocation factor of Cd and Pb with most plant species are greater than 1, indicating that these moved more easily in these plants. However, these results also showed that the translocation of Cd and Pb from root to shoot of Phragmites australis and Lycium shawii plants was higher than other metals. Similar pattern was observed with Malva parviflora and Rhazya stricta. In conclusion, none of our studied plant species were identified as hyperaccumulator; however, Phragmites australis and Lycium shawii together with Malva parviflora and Rhazya stricta showed a highly positive phytoextraction potential for Cd and Pb. whereas,, Datura stramonium and Citrullus colocynthis were found to be suitable for phytostabilization of soils contaminated with Ni and Cu.