PHYTOEXTRACTION OF HEAVY METALS FROM A DECOMMISSIONED TANNERY WASTE DISPOSAL AREA BY PIONEER HERBACEOUS PLANTS

Abstract

A field survey of pioneer herbaceous plants growing on a decommissioned tannery waste disposal area in Hubei Province, China, was conducted to identify the species extracting heavy metals especially accumulating Cr in their tissues. The results show that the soil in the area was extremely contaminated with soil Cr range of 1300–3100 mg/kg, which was 13–30 times higher than that of unpolluted soil. Besides, 18 herbaceous species belonging to 11 families were found in the polluted area, among which 8 species, were identified as the dominant adaptive species with Cr > 200 mg/kg in their shoots and occupying dominant biomass. Cynodon dactylon L. was found to have the highest Cr concentration 774 mg/kg and 2335 mg/kg respectively in its shoot and root. The Cr bioaccumulation coefficients and translocation factors of dominant herbaceous plants both were lower than 1, indicating that the plants were possibly tolerant-stratified to the high Cr environment. Cynodon dactylon L. was considered as the suitable candidate for bioremediation of Cr-contaminated soils in the area.