Poincianella pluviosa as biomonitor of heavy metals in the municipality of Volta Redonda, RJ, Brazil

ABSTRACT The present study aimed to determine heavy metal concentrations in the tree bark of the species Poincianella pluviosa in Volta Redonda municipality, Rio de Janeiro. Four sets of barks of eight trees with three replicates each from sectors 1 (W), 2 (S), 3 (E), and 4 (N) of the Volta Redonda center corresponding to the cardinal points were collected. The samples were digested in a nitroperchloric mixture and the lead (Pb), cadmium (Cd), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) contents were determined by atomic absorption spectrophotometry. The cluster analysis (CA) formed 12 groups; among them, group 3 (G3) showed the presence of all seven elements in sector 1 and group 8 (G8) showed the presence of Pb, Zn, Fe, Ni, and Mn in sector 2. Kruskal-Wallis and Bonferroni tests showed that all elements presented statistically different values among the four sectors when compared with each other (p > 0.05). Sectors 1, 2, and 3 had the highest concentrations of heavy metals, which are directly associated with vehicle and railroad flow and iron and steel activities that are concentrated in these sectors. Bark can be used as an effective method for the monitoring of air pollution in urban areas.