Determination of Heavy Metal Concentration in Borehole Water and Mineral Composition, and Radionuclides in Sediments from Ha-Masia Tshikwarani Village

In rural regions of South Africa, groundwater sourced from boreholes is now recognised as the primary source of drinking water. The quality of this water is affected by the presence of heavy metals and the mineral content of various rock types, with heavy metals playing a significant role in water hardness. This research evaluates the quality and suitability of groundwater for drinking and domestic use by examining the concentrations of heavy metals, elemental composition, and radionuclides in borehole water and soil sediments. Water and soil samples were collected from the borehole in Ha-Masia Tshikwarani Village. The quantities of heavy metals (As, Cd, Cr, and Ni) in the borehole water and soil sediments were measured using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The findings indicated that As, Cd, and Ni were not detected in the water samples, while Cr was found at an average concentration of 0,003 mg/L and 0,006 mg/L for both seasonal periods. Analysis of the sediment samples revealed the average concentrations of Ni and Cr as follows: Ni (7.78, 5.33, 8.93, 9.66, 10.40, 10.51, and 10.28 mg/kg) and Cr (15.58, 12.99, 25.19, 21.07, 31.43, 26.57, and 22.81 mg/kg). These results demonstrated that the heavy metal concentrations in both water and sediment samples from this borehole were within the permissible limits set by DWAF (1996) and the Canadian Council of Ministers of the Environment (CCME) sediment quality guidelines (SQGs). The elemental composition of sediment samples from borehole cuttings at Masia Tshikwarani was analyzed using X-ray Diffraction, revealing 13 mineral compositions expressed as weight percentages (wt.%) at various concentrations. Albite, Quartz, Microcline, and Mica were identified as the predominant soil minerals. Amphiboles and oxide minerals were also frequently observed, alongside smaller amounts of other mineral phases, such as clay minerals. The AT6101DR detector was used to analyse radionuclide levels in soil sediment. The following radionuclides were present: ⁴⁰K, ²¹²Pb, ²²⁸Ac, ²⁰⁸Ti, and ²¹⁴Bi, at depths of 19 m, 57 m, 63 m, 83 m and 120 m, respectively. At depths of 3 m and 46 m, only ⁴⁰K, ²²⁸Ac, and ²⁰⁸Ti were present. The overall dose rate for radionuclides ranged from 0.067 to 0.078 µSv/h, equivalent to 586.92 to 683.28 µSv/yr, which is below the permissible limit of 1000 µSv/yr. The findings offer crucial information for consumers, and ongoing monitoring is advised to maintain water safety.