The Effect of Leaf Litter on Phytoextraction of Cr(VI) by Two Salicaceae Species from Contaminated Soils

Contamination of the agricultural land by the toxic chromium is considered as a worldwide hazard that has accelerated dramatically since the beginning of industrial revolution. phytoextraction as an alternative treatment has shown great potential for remediation of heavy metal-contaminated soils. The present work is an attempt to assess the ability of Populus alba L. and Populus nigra L. for the phytoextraction of Cr(VI) from a contaminated soil and leaf litter usefulness for increase the phytoextraction efficiency. To prepare amended substrate, loam soil and leaf litter were mixed in 1:1 (v/v) ratio (P50%). The substrate were contaminated with 50, 100 and 150 mg kg-1 of Cr(VI) [were spiked as potassium dichromate (K2Cr2O7)]. Homogenously and uniform-in-size rooted cuttings of P. alba L. and P. nigra L. were transplanted in contaminated substrates. At the end of growing season, the amounts of Cr accumulation in leaves, shoots and roots were measured. The results indicated that, in all treatments, Cr(VI) was accumulated in roots, shoots and leaves of seedlings. Amended substrate was able to enhance the total uptake of Cr by plants (P<0.01). This study thus suggested that the leaf litter due to its conditions that prepare to poplar root system and not having any outcome for the environment could be exploited for remediation of chromium from chromium contaminated sites.