Trace Metal Deposition on Soil and Accumulation in Plants around a Coal Power Station in Pretoria, South Africa

Abstract

Combustion of coal in power stations is one of the main sources of environmental pollution due to the generation of trace metals. This study investigated levels of trace metals from five different plants and soils around a coal-fired power station in Tshwane, South Africa. Plants and soil samples were collected from different points (10, 500 and 750 m) along different directions (North West, North East, South West and South East) and analyzed for metals contents using Inductive Couple Plasma–Optical Emission Spectrophotometer (ICP-OES). A significant increase in the concentration of trace metals was detected from the stack pointing to the effect of the long stack in depositing more trace metals at a distance of 750 m away from the power station. Digitaria diagonalis and Tagetes minuta have significantly higher concentrations of trace metals than other plants collected around the area (p < 0.05). The soil pH was in the range 5.13 ± 0.11 to 6.01 ± 0.12. The concentrations for all elements in soil were recorded in the following descending order: Fe > Al > Mg > Cr > Zn > Cu > Pb >Ni > Co.