Chromium, nickel, lead and zinc accumulation and performance in relation to their use in phytoremediation of macrophyte Limnobium laevigatum

DANIELA S. ARÁN; CARLOS A. HARGUINTEGUY; ALICIA FERNÁNDEZ CIRELLI; M. LUISA PIGNATA

Buenos Aires

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

Society of Environmental Toxicology and Chemistry (SETAC) Latin America

The contamination of aquatic environments is a major problem worldwide, and heavy metals are among the most common pollutants because of their transfer and accumulation occurring in different biotic and abiotic compartments. It is known that heavy metals in aquatic systems can be easily absorbed and accumulated in aquatic plants. Therefore, in order to study the accumulation of chromium, nickel, lead and zinc and the stress response for their use in the phytoremediation of aquatic environments, the floating aquatic plant Limnobium laevigatum was exposed to increasing concentrations of a mixture of these metals (Cr: 0,002 ? 2,0 mg L-1; Ni: 0,025 ? 0,5 mg L-1; Pb: 0,001 ? 2 mg L-1; Zn: 0,03 ? 0,1 mg L-1) for 7 days. The accumulation of Cr, Ni, Pb and Zn in plants was determined using GFAAS (graphite furnace atomic absorption spectrometer, Analyst 600, PerkinElmer, USA) and their effects on physiological parameters (chlorophyll a and b concentration and degradation, carotenoids concentration, lipid peroxidation measured as malondialdehyde and HPCD) were evaluated using Beckman DU 7000 spectrophotometer. The data obtained were analyzed by analysis of variance (ANOVA), at a significance level of p < 0.01, to investigate differences between treatments which were followed by a posteriori test (p < 0.05). It was determined that L. laevigatum could accumulate appreciable amounts of Cr, Ni, Pb and Zn in its tissues, and the concentrations of these metals in L. laevigatum were dependent on the metal concentration in the exposure medium after 7 days. The physiological changes observed in L. laevigatum, at moderate metals concentrations in their tissues, did not represent a risk in relation to its survival during the study period. A decrease in chlorophylls and an increase in pheophytins and carotenoids concentrations were observed with the increase in metals concentrations, but at moderate concentrations of Cr, Ni, Pb and Zn, the changes in the photosynthetic apparatus were not significant. Regarding lipid peroxidation, the HPCD did not show variations at higher concentrations of metals and the MDA showed a decrease in the highest concentrations of Cr, Ni, Pb and Zn. Taking into account the accumulation capacity and tolerance to heavy metals, L. laevigatum is suitable for phytoremediation in aquatic environments contaminated with moderated concentrations of Cr, Ni, Pb and Zn.