Assessment of the Influence of Coal Mining on Groundwater Quality: Case of Masisi Village in the Limpopo Province of South Africa

Coal mining in different coalfields in South Africa is known for decades (approximate to 146 years) and its economic importance to the country has recently surpassed commodities such as gold. One of the Coalfield that is well known for coal production in the Limpopo province of South Africa is Pafuri Coalfield where Tshikondeni Colliery operated for 32 years before closure in 2014. In general, coal extraction has several environmental problems which include acid mine drainage that is now a serious problem currently confronting the government of South Africa. This therefore creates a need to proactively prevent or minimize potential groundwater impacts through long term monitoring of water quality meant for both domestic and commercial use. Assessment of borehole water quality at Masisi Village was vital due to its close proximity to Tshikondeni Coal mine. Groundwater samples were collected from 22 active boreholes at Masisi Village and were analysed for a range of chemical constituents such as electrical conductivity, pH, total dissolved solids, turbidity, PO42-, SO42-, NO32-, Mg, Zn, Cu, Cd, Cl-, Cr, F-, Fe, Mn, Ni, Se, Na, Mo, Ca, Pb, Sb, Ba, Al, Co, V, K, Al and As. Anions were analysed using the Ion Chromatography whilst, cations were determined using the Inductive Coupled Plasma Mass Spectroscopy technique. The physico-chemical parameters were compared with the Department of Water Affairs and Forestry (DWAF) and World Health Organization (WHO) standards for drinking water and public health. This was done in order to establish the quality of the groundwater resources in the study area. Most parameters complied with the DWAF and WHO guideline values for drinking-water. However, TDS, EC,Cl-, NO32-, Mn, As, Cd, Cr, Pb, Mo, K, V, Sb, Ba and Mg exceeded WHO and DWAF permissible concentration with Pollution index >1 in all the boreholes. This gave an indication that groundwater resources at Masisi could be significantly contaminated. According to DWAF (1996) and Peplow and Admunds (2004). Long term exposure to polluted water can cause neurological disorders, cancer, renal damage and respiratory problems resulting in high mobirdity and mortality rates from water borne disease that lead to epidemics. The study concluded that all boreholes at Masisi were contaminated and hence not suitable for human consumption. The outcome of this study may be used as baseline data for groundwater quality control for both domestic and commercial use by municipal authorities. A study of acid producing potentials of discard dumps at the mine was suggested in order to ascertain the source of the contaminants. Continuous monitoring of ground water quality within 10 km radius of Tshikondeni mine and making primary and secondary treatment mandatory before using it was also advised.