Heavy metal pollution in soil and plants from a mining area in the North West Province, South Africa
Raji, lyioluwa Busuyi
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South Africa is a mining country with a huge reserve of large deposits of gold, platinum, and coal, among others. However, contamination of soils and plants by heavy metals within the mining environment in South Africa has not been investigated as it should have been. Heavy metals have the tendency of entering the food chain and end up being consumed by humans either directly or indirectly. At high concentration in living body, heavy metals damage organs. This study analyzed the concentration of heavy metals in soils and the plant found in the environment of a gold mine located in the North West Province, South Africa. The sampling depths for soil were 0-10 cm and 10-20 cm at various distances, namely 500 m and 1000 m around the mining site. The soil and plant, Eragrostic hy noides, samples were analysed for Cd, Zn, Pb and As using inductively coupled plasma spectrometry (ICP-MS). Concentration factor was used for the determination of heavy metal uptake by the plant. The risk quotient was used in this study to determine the health risk associated with heavy metal contamination. A spatial variability of heavy metal contamination was created in the Geographical Information System environment by ordinary kriging. The concentrations of heavy metals in the soil showed that the levels are within the South African threshold and below some other countries ' thresholds. In the leaf and the root tissue of the sampled plant, the trend of heavy metal concentration was Zn > Pb > As > Cd. The results of the concentration factor (CF) revealed that Eragrostic hypnoides accumulated Zn and Cd from the soil. The CF was above 1. However, the CF of the arsenic and lead was below 1 in all the sampled locations except at the Northern part of the mine within the 1000 m radius of the mine. The map of spatial variability revealed that higher concentration of heavy metals were found close to the mining site. In conclusion, the heavy metal concentration accumulated in the plant of the study area could be harmful to the health of the direct and indirect consumer. Future study should be done on agricultural products produced within this vicinity in order to assess the concentration of heavy metals in the crops most especially the extensive maize plantation within the locality.