Capacity of Salvinia minima Baker to Tolerate and Accumulate As and Pb

Abstract

The use of Salvinia minima Baker for the removal of lead (Pb) and arsenic (As) from aqueous solutions was investigated. In a first approach, the effect of different concentrations of AsO43- and Pb(II) on the growth and accumulation of these metals was studied. The plants tolerated concentrations of 20-40 muM Pb(II) and 200 muM of AsO43-. Toxic effects occurred when 20 muM of Pb(II) and 100 muM AsO43- were used. These effects included growth inhibition (decreased yield of biomass and frond area) as well as an altered frond (leaf-like structure in ferns) appearance and tissue consistence. S. minima showed a high uptake of Pb (34 mg/g dry weight) compared to As (0.5 mg/g dry weight). The uptake of As was inhibited by phosphate. Additional kinetic studies revealed a two-stage accumulation of both elements: a rapid first phase within the first 6-12 hours and a slow second phase up to the end of the 96-hour experiment.