Natural and induced heavy-metal accumulation by Arrhenatherum elatius:: Implications for phytoremediation

The uptake of cobalt, copper, lead, and nickel by the perennial metal-tolerant grass Arrhenatherum elatius was studied by growing the plants in two different substrates. These were a cobalt/copper/nickel ore (Experiment A) and base-metal tailings rich in lead (Experiment B). The enhancement of metal uptake by the plants following addition of EDTA was investigated in both experiments. In Experiment A, metal concentrations in dry plant matter were about equal to the acid-extractable (1 M hydrochloric acid) fractions in the supporting soils after addition of 4 g kg(-1) EDTA, In Experiment B, the base-metal tailings contained 11,500 mg kg(-1) (1.15%) lead. The EDTA addition induced 2.5% lead (dry matter) in the grass. This was reduced to ca. 1.0% upon addition of lime. The results indicate that A. elatius may have some potential in phytoremediation operations if EDTA is added to the substrate.