Trace metals in soil and plants around a cement factory in Pretoria, South Africa

© 2015, Polish Journal of Environmental Studies. All rights reserved. Rapid economic development across South Africa in recent decades has necessitated massive construction and building works, resulting in an increased demand for cement production. This has set cement factories all over South Africa to operate at maximum capacity in a bid to meet market demands. The present study investigated the concentrations of trace metals in soil and plants around a cement factory (PPC) in Pretoria, South Africa. Soil sampling was carried out around the cement factory during winter and summer periods, while plant sampling was only carried out during the summer period. Thirty soil samples were collected in different directions – southwest (SW), southeast (SE), and northeast (NE) – of the sites. Plant samples were also collected from these different directions. The result showed that soil pH was in the acidic medium and ranged from 5.12±0.21-5.67±0.23. There was a significant difference in the concentrations of trace metals from the different directions (p<0.05). The pollution index (PI) revealed that the soil has been moderately polluted with elements such as Pb, Ni, Cr, Zn, Cd, and Cu. Strong positive correlations were recorded for most of these elements, suggesting a common source for them. The result of the plant analysis showed that Panicum maximum bio-accumulated most of the trace metals from the soil. L. camara showed a prospect as a bio-accumulator of heavy metals from these plants. The levels of trace metals from the plants exceeded the acceptable limits for human and livestock consumption. The study revealed that the source of the trace metals as pollutants cannot be attributed to the cement factory only but also to vehicular emissions.