Lead phytoextraction, using plants to extract Pb from contaminated soils, is an emerging technology. Calculations of soil Pb mass balance suggest that this technology will be economically feasible only if systems can be developed to employ high biomass plants that can accumulate greater than 1% Pb in their shoots. In this study, we investigated the potential of adding chelates to Pb-contaminated soils to increase Pb accumulation in plants. The addition of chelates to a Pb-contaminated soil (total soil Pb 2500 mg kg-1) increased shoot Pb concentrations of corn (Zea mays L. cv. Fiesta) and pea (Pisum sativum L. cv. Sparkle) from less than 500 mg kg-1 to more than 10000 mg kg-1. The surge of Pb accumulation in these plants was associated with the surge of Pb level in the soil solution due to the addition of chelates to the soil. For the chelates tested, the order of the effectiveness in increasing Pb desorption from the soil was EDTA > HEDTA > DTPA > EGTA >EDDHA. We also found that EDTA significantly increas...