Ecological risk of trace metals in soil from gold mining region in South Africa

The Witwatersrand basin in South Africa is one of the well-known gold mining regions worldwide. Plausibly, it is one of the sites in South Africa with the highest environmental impact emanating from trace metal contamination. This study assessed the concentration of Fe, S, Cu, Mn, Cr, Zn, Ni, Co, P, Mo using inductively coupled plasma optical emission spectrometry on 21 soil samples that were collected from 9 independently located historical gold mine tailings. The results revealed high mean concentration (mg/kg) for Fe (36,433.39) > S (5,071.83) > Cu (1,717,28) > Mn (612.81) > Cr (74.52) > Zn (68.67) > Ni (40.44) > Co (9.63) > P (3.49) > Mo > (2.74) in the samples investigated. Estimated degree of contamination by using contamination indices calculations showed that the sites surveyed are on average low to moderately contaminated with Co, Cr, Cu, Mn, Ni, S, and Zn. The trace metals that are most likely to cause ecological risk incorporate Mn and Cu, especially at Durban Deep. While the health risk assessment revealed a low ecological risk (Eir ) of Cr, Ni, and Zn, the Eir estimates showed that the residents in the study area are prone to health risk mainly from the covetous effects of Cu (320 & LE; Eir ). The residents of the study area are low income earners and the possibility that they can relocate is nonexistent. Thus, mitigation strategies are required to avoid eminent health risks and restraining housing developments near the tailing dumps.