THE POTENTIAL FOR PHYTOEXTRACTION OF HEXACHLORO- CYCLOHEXANES CONTAMINATED CALCAREOUS SOILS IN EASTERN SUBURB OF BEIJING BY COTTON

摘要

Phytoextraction with high biomass non-food plants has been proposed as a promising method to remediate heavy metals or organic pollutants contaminated soils. Through pot experiments, this present study was tired to investigate the potential of the native plant, cotton (Gossypium hirsutum L.) for phytoextraction of calcareous soils contaminated by hexachlorocyclohexane (HCHs). The plants grew for about 160 days in soils spiked with HCHs including four main HCH isomers (α-, β-, γ-, and δ-HCH) at 0, 0.016, 0.04, 0.2, 0.4 and 0.8 mg HCHs kg"1 soil. The results revealed that the highest HCHs concentrations were observed in the leaves, followed by the roots and the stems, however, none of the four HCH isomers were almost detected in the seeds. The total HCHs concentrations in the roots, stems and leaves were well correlated with those in pot soil, while the relative distribution of the four isomers in the plant tissues differed from that in the pot soils. The bioconcentration factors (BCFs) of the plants ranged between 0.34 and 5.83, and decreased with the increment of HCHs contents in the pot soils. The calculated phytoextraction efficiency of the plant under various HCHs treatments ranged between 0.6% and 9.9%. From the results, further research still need to be done for optimizing phytoextraction technology if cotton plants to be used as HCHs phytoextractor in the future.