PHYTOEXTRACTION OF ZINC BY OAT (AVENA-SATIVA), BARLEY (HORDEUM-VULGARE), AND INDIAN MUSTARD (BRASSICA-JUNCEA)

The success of phytoremediation hinges on the selection of plant speci es and soil amendments that maximize contaminant removal. Indian musta rd (Brassica juncea) has been shown to be effective in phytoextracting Zn, particularly after the synthetic chelate EDTA has been applied to the soil. However, the effectiveness of grass species for phytoremedi ation has not been addressed in great detail. A hydroponic screening o f 22 grass species indicated that oat (Avena sativa) and barley (Horde um vulgare) tolerated the high Cu, Cd, and Zn concentrations present i n the solution and also accumulated elevated concentrations of these m etals in the plant shoots. A hydroponic experiment comparing these two grasses to Indian mustard indicated that, although shoot Zn concentra tions were greater for Indian mustard, the grasses were considerably m ore tolerant. A pot experiment conducted using a Zn-contaminated soil showed that the addition of EDTA to the soil significantly increased Z n accumulation by B. juncea but not oat or barley. Nevertheless, barle y accumulated >2 mg of Zn plant(-1), 2-4 times more Zn than what was o bserved in Indian mustard in the presence of EDTA. The results of this experiment suggest that barley has a phytoremediation potential equal to, if not greater than, that for B. juncea.