Fitoacumulación y translocación de cromo en Eichhornia crassipes y Pistia stratiotes durante el tratamiento de efluentes contaminados

Abstract

Plants can remove metals from aqueous systems, based on strategies such as metal exclusion; or by its accumulation in leaves and pseudostem in non-toxic form. The capacity of phytosorption and translocation of Pistia stratiotes and Eichhornia crassipes was evaluated, exposing them to Cr(VI): 5, 10, 25 and 50 mgL -1 . The experimental units consisted of glass bottles containing 0.5L of synthetic effluent, fertilizer and one plant per container. These were maintained with luminous intensity 106±23 μmol quanta m s -1 , light: darkness periods: 12:12h, and 28±2ºC. The determination of Cr(VI) was carried out in the medium, at the beginning and every 24h, for 10 days. The Cr(total) in plant was determined at the end of the treatment. The biggest removal was obtained using Eichhornia with 98.0 and 97.1% in the treatments at 5 and 10 mgCr (VI) L -1 , respectively. While for the same, Pistia removed 80.2 and 74.0%. The highest bioaccumulation was observed at the root level, with a bioaccumulation factor (FB) between 360-370 for Pistia and 490-708 for Eichhornia . Both plants achieved low values for translocation factor (FT<0.1). The plants showed an efficient bioaccumulation of the metal, following an exclusion mechanism that allows their photosynthetic apparatus not to be affected during the treatment.