Investigating Jacaranda mimosifolia tree as biomonitor of atmospheric trace metals.

Studies on the use of tree bark as biomonitors for environmental pollutants are still very scarce. We evaluated the reliability of using Jacaranda mimosifolia, a common tree in Tshwane City of South Africa, as a suitable biomonitor of atmospheric trace metals. Bark samples were collected from ten different locations during two sampling periods. The concentrations of the metals were determined by inductively coupled plasma mass spectrometry. The concentrations of the metals were 33.2-1,795 microg/g (Pb), 21.4-210 microg/g (Cu), 68.4-490 microg/g (Zn), 30.6-2,916 microg/g (Cr), 0.12-1.34 microg/g (Cd), and 6.04-68.0 microg/g (V), respectively. The differences obtained for the results from different sites were significant (p < 0.05). A significant difference was also observed between the two sampling periods. The trace metals concentrations suggested that automobile emissions are a major source of these metals. The study also confirms the suitability of J. mimosifolia as a biomonitor of atmospheric deposition of these metals.