Abstract

To evaluate the phytostabilization and/or phytoextraction capacity of Atriplex halimus and Chrysopogon zizanioides species, chelating agents (CA, citric acid; FA, fulvic acids) and a vegetal organic amendment (OA) were added to a soil highly contaminated with lead (2,952±280 mg Pb kg-1 and pH 6.30±0.13 ), located at Valparaíso Region (273017 m E, 6386884 m S) in Central Chile. Two independent assays were established and six treatments were evaluated in each case (T1: control, T2: CA, T3: FA, T4: OA; T5: CA+OA, T6: FA+OA). Chelating agents were applied to irrigation water considering a concentration of 4 g L-1, while the OA was applied at the beginning of the experiment with a volumetric dose of 5%. After 180 days, continuous application of chelating agents in A. halimus increased significantly the Pb concentrations in plants, an effect that was enhanced by application of OA, reaching concentrations of 32, 42 y 360 mg Pb kg-1 in leaves, stems and roots, respectively. Similar effects were observed on C. zizanioides, but only at 90 experimental days, where the CA and OA additions increased significantly the concentrations up to 46 mg Pb kg-1 (leaves) and 284 mg Pb kg-1 (roots). On the other hand, only in A. halimus the AF application increased the total dry matter, while CA decreased the leaves dry matter at 180 days of experiment. In general, both plant species showed higher Pb concentration in roots than in the aerial part, presenting a high potential to phytostabilization of soils contaminated with Pb.