Analysis of the radionuclides and heavy metal concentrations of the Vaal River, South Africa

Year
2024
Author(s)
Boitshekwane Chobeka - Centre for Applied Radiation Science and Technology, North-West University (NWU)
Manny Mathuthu - Centre for Applied Radiation Science and Technology, North-West University (NWU)
Ocwelwang Atsile - Centre for Nuclear Safety and Security (CNSS), National Nuclear Regulator (NNR)
Abstract

Background: This study was carried out to examine the radionuclides and heavy metals concentrations in water the upstream and downstream of the Vaal River of South Africa.  Methods: The study used the ICP-MS to determine radionuclides and heavy metals. The total 27 water samples was collected for analysis. Analysis were mainly for elements such as Li, B, Pb, Cu, Co, Ni, Zn, Mn, Fe, and P, radionuclides such as K, Th and U using ICP-MS.  Results: The carcinogenic human health risk values in mg/l of heavy metals we estimated using the USEPA 2011 guideline. The chronic daily intake (CDI), hazard quotient (HQ), and hazard index (HI) due to ingestion of the river water were calculated from the adopted USEPA 2011 guideline. The risk value were estimated for the adult at 70 years with the body weight of 70 kg and a child at 15 years, with the body weight of 15kg. The CDI in mg/kg/day had high concentrations with Cu at 9, 33E+02, B, P and Zn with a constant concentration of 5, 60E+02. The calculated risk value was observed at greater than 1, as a results of carcinogenic cancer risks.  The K, Th and U in Bq/l were also analysed using the ICP-MS. The radium equivalent activity (Raeq), dose rate (D), annual effective dose (AEDE), external hazard (Hex) and internal hazard (Hin) index were used to determine the potential radiological risks. The calculated average radiation hazard for Raeq was (33,803 Bq/l), D (18,158 nGy/hr), AEDE (0, 0222 nGy/hr), Hex (0,091) and Hin (0,096) in this study. These hazard parameters were lower than the world average permissible limit, As a result, the hazard parameters does not pose radiological risks due to ingestion of river water.