Distribui？？o de metais pesados na vegeta？？o metalófica de Carajás

this study was conduted in the north range (serra norte), one of the geographic formations of the carajás mineral complex, located in the municipality of paraupebas, state of pará, brazil. concentrations of heavy metals were determined in plant tissues and soils. the five species selected for study were: bauhinia pulchella (leguminosae caesalpioideae), cuphea annullata (lythraceae) - ipomoea cavalcantei (convolvulaceae) - mimosa acutistipula var. ferrea (leguminosae mimosoideae) and callisthene minor (vochysiaceae). the metals analyzed were iron (fe), manganese (mn), copper (cu), nickel (ni), chorium (cr) and lead (pb). the levels of exchangeable metals in the soil were similar at the edge and in the center of the mineral deposit. the tissues of the five plant species analyzed had abnormally high levels of fe, ni and cr. each of the plant species tested is tolerant of the metals considered. it is assumed that the interaction of these metals neutralizes their damaging effects on the plants studied. this interaction is a form of tolerance. baunhia pulchella surpassed the other species in the accumulation of nickel. it is possible that the high concentration if ni in this plant is related to the xerophytic conditions of the "canga' environment.