Assessment of Radionuclides Concentration and Health risks of Boreholes in a Typical Nigeria University

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Abstract

This study investigated the concentration of radionuclides and the associated health risks from the consumption of water from the boreholes of two selected campuses of Osun State University, Nigeria. A total of sixteen water samples were collected from the standpipes connected to each of the boreholes for both rainy and dry seasons. The samples were weighed and sealed using cylindrical plastic containers wrapped with masking tape to attain secular equilibrium between the parent and daughter’s nuclides. A Gamma-ray spectrometry was carried out by counting each sample for 10 hours using well-calibrated Cesium Iodide (CsI) scintillation detector processing the spectra using a universal radiation Spectrum Analyzer (URSA II). The results were subjected to statistical correlation, and ANOVA analysis using SPSS version 22. The annual effective dose was calculated for adults and compared with standards. Results showed that the physical characteristics such as pH, TDS, EC, and temperature were within permissible levels except for a few boreholes in Osogbo and Ejigbo campuses that are slightly acidic (pH less than 6.5) and a bit mineralized (EC greater than 1000 µS/cm). The concentration (Bq/L) of 238U, 232Th and 40K range between 9.48-9.99, 14.90-16.72 and 129.56-190.94, respectively, in the Osogbo campus, while that of Ejigbo is between 8,01-10.37, 14.59-16.72 and 136.38-204.58, respectively. The annual effective dose from the ingestion of water from the boreholes is within the range of 3.40-3.82 µSv year-1. Based on the physical and radionuclides characteristics of the water from all the boreholes, the water is safe for drinking, however, adjusting the pH to the alkaline range may reduce the dissolution of more minerals into the groundwater.

Keywords: Boreholes, Concentration, Health risk, Radionuclides, Water

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