In a greenhouse experiment, the ability of sunflower (Helianthus annuus L.), castor bean (Ricinus communis L.), tobacco (Nicotiana tabacum L.), and Amazon pepper (Capsicum baccatum L.) to extract Cd and Zn from an oxisol contaminated with heavy metals was evaluated. The experiment was carried out in a complete ramdomized block design in a factorial scheme consisted of 4 species x 3 rates of metals x 2 rates of EDTA, with 3 replicates and using plastic pots with 3 L capacity. Heavy metals were applied to the soil, as inorganic salts, at rates, in mg kg-1: dose 0: control (no metals added); dose 1: - combined application of 0.75 of Cd; 6.25 of Pb; 20.0 of Cu; 8.75 of Ni and 62.5 of Zn; and dose 2 - combined application of 1.5 of Cd; 12.5 of Pb; 40.0 of Cu; 17.5 of Ni and 125,0 of Zn, with and without EDTA addition of 1 mmol kg-1. Plant tops were harvested from 48 to 100 days after sowing or seedlings transplant to the pots. EDTA addition decreased dry matter yield of all species, although it contributed to the increase of shoot Cd concentration on castor bean and sunflower plants, and had no effect on Zn shoot concentration for all species under investigation. Tobbaco was the most efficient specie in extracting Zn and Cd from the contaminated soil. A great number of sunflower, Amazon pepper and tobacco cropping will be necessary for soil decontamination, if it receives the addition of EDTA at rate of 1 mmol kg-1.
Phytoremediation; EDTA; tobacco; castor bean; pepper; sunflower; soil pollution
