Concentrations of trace metals in Permalia sulcata transplanted around a coal fired power station in Pretoria, South Africa

The increased use of coal for power generation may increase the concentrations of different forms of pollutants and trace metals into the environment. The present study investigated the concentrations of trace metals in transplanted lichen (Permalia sulcata) around a coal fired power station in Pretoria, South Africa. Lichen thalli were harvested from an unpolluted site and transplanted on trees around a coal fired power station at a distance of 500 m away from the stacks and at two different directions (Southwest and Northwest). The lichen thalli were allowed to grow for a period of 12 weeks before harvesting in July and further 12 weeks before harvesting in October. The harvested lichen thalli were then analysed for trace metal contents using inductively coupled plasma mass spectrometry (ICP-MS). The result showed a significant difference in the concentrations of all the trace metals from the two sites (p < 0.05). Seasonal variations in the concentrations of some of trace metals were also significant (P<0.05). The enrichment factors showed an increase in the concentrations of trace metals obtained from the thalli. The trend in the concentration of trace metals was in the order Mg> Fe > Al > Cr > Co > Cu > Ni > Pb > Zn. The study proved that the continuous reliance on coal for power generation without the adoption of proper emission control system may result in increased deposition of trace metals as pollutants around the power plant.