Seleção de espécies com potencial fitorremediador de chumbo

Abstract

Nutrient solution study carried out under greenhouse condition evaluated the lead extraction potential several species vegetal. The treatments were arranged as a completely randomized design in a 6x5 factorial scheme. Six plant species: Vetiver (Vetiveria zizanioides L.), sunflower (Helianthus annuus L.), bean (Canavalia ensiformis L), Elephant Ear (Alocasia macrorrhiza), singônio (Syngonium angustatum) and embaúba (Cecopria sp) were evaluated under 5 lead concentrations (0, 50, 100, 200 and 400 mg L-1 Pb) in a 50% strength Hoagland and Arnon (1950) nutrient solution. The lead was added to the system as lead acetate trihydrate. The study was conducted for 31 days, evaluated the content of Pb in the plant, the effect on biomass production in root architecture, the accumulation of Pb and ability to bioaccumulate and transfer of Pb by the species. The leaf and root lead content of the species increased with concentrations of Pb in the nutrient solution. However, the exposure of plants to lead reduced shoot and root biomass at the highest Pb concentration. The sunflower plants presented the highest Pb accumulation (0.60 mg pot-1), while embaúba (BF = 1.088), followed by vetiver (BF = 0.627) and sunflower (0.382) had biggest bioaccumulation factor (BF). Sunflower also had highest shoot biomass. The species had higher root length were elephant ear, vetiver and sunflower. None of the species evaluated are suitable for phytoextraction, but sunflower, elephant ear and vetiver given high biomass production, Pb content of roots and root length presented the potential for phytostabilization of contaminated sites.