POTENTIAL OF THE SHRUB Lantana camara L. (VERBENACEAE) FOR THE PHYTOSTABILIZATION AND VOLATILIZATION OF MERCURY

Abstract

Mercury (Hg) is the most harmful heavy metal for living beings due to its high toxicity, persistence, and bioaugmentation in the food web. Lantana camara has been considered promising for the phytoremediation of different metals, but its response to Hg has not been characterized. The objective of this study was to evaluate the effectiveness of L. camara to bioaccumulate, translocate, and volatilize Hg in artificially contaminated soils (1.0 and 8.0 mg/kg Hg). After two months of treatment, the dry weight was measured and the Hg present in stems, roots, leaves, and atmosphere was quantified using atomic absorption spectroscopy. The volatilized Hg was captured in hermetic chambers with continuous airflow, connected to a trap solution (5 % KMnO4 dissolved in H2SO4). The translocation factor was < 1, and the bioaccumulation factor was > 1 in both treatments. The Hgº values volatilized in high mercury indicate that approximately 7.1 µg/g plant/day can be released into the atmosphere. Our results indicate that L. camara accumulates Hg mainly in the root, showing potential for phytostabilization, but the observed volatilization rates point towards a more restricted use of this species in phytoremediation strategies.