The Distribution of Toxic Metals in Sediments: Case study of New Union Gold Mine Tailings, Limpopo, South Africa

摘要

The study revealed that the toxic metals (Mn, Cu, Cd, Co, Zn and Ni) were distributed in the upper part of the river and stream sediments (0-20 cm). The concentration of the heavy metals were arranged in descending order where Manganese> Copper> Nickeb Zino Cobalt> Cadmium. The range of toxic metals in the top and bottom layer was: Mn (99.1 ± 0.1 to 203.5 ± 2.1 mg/kg); Cu (8.9 ± 0.1 to 65.7 + 4.0 mg/kg); Ni (6.1 ± 0.1 to 63.5 ± 1.2 mg/kg); Zn (12.5 ± 0.6 to 36.2 ± 0.3 mg/kg); Co (4.1 ± 0.1 to 18.8 ± 0.5 mg/kg); Cd (0.2 +0.00 to 1.3 ±0.1 mg/kg) respectfully. The pH of top soil profile ranged from 3.25 ± 0.01 to 6.28 + 0.02 whereas the bottom soil profile ranged from 3.75 + 0.01 to 6.45 ± 0.03. The electrical conductivity of top layer sediments in the stream and the Mandzoro River ranged from 8.5 + 0.20 to 16.3 ± 0.1 mS/cm and the bottom layer ranged from 8.4 ± 0.20 to 15.3 + 0.23 mS/cm. The increase of these toxic metals in the bottom profile has the potential to contaminate groundwater supplies, which is a source of drinking water for the rural community. Also the presence of the toxic metals in top profile in river sediments has the potential to impact negatively on aquatic organisms.