BASELINE RADIOLOGICAL ASSESSMENT OF SOIL AND WATER AROUND DANGOTE REFINERY, PRIOR TO COMMERCIAL PRODUCTION IN LAGOS, NIGERIA

Abstract

The increasing industrialization of urban landscapes necessitates comprehensive environmental safety evaluations, especially concerning radiological impacts. This study presents a pre-commercial production radiological assessment of soil and water in Dangote Refinery’s neighbourhood arising from the presence of the naturally occurring radionuclides - uranium-238 (238U), thorium-232 (232Th), and potassium-40 (40K). The investigation aims to establish baseline data on the activity concentrations of these radionuclides in soil and hand-dug well water samples collected from three communities within a 2.5 km radius of the refinery site. Sodium Iodide [NaI(Ti)] gamma spectrometry was employed for radionuclide analysis, with results interpreted in accordance with the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) guidelines. The results showed that the distribution of the radionuclides activity concentrations (Bq/kg) in soil samples falls between 8.00±1.91 and 12.00±4.95 for 238U, 8.00±1.38 and 10.00±5.43 for 232Th, 297.32±4.41 and 328.12±4.07 for 40K in soil samples; whereas in hand-dug well water samples, the activity concentration (Bqm-3) ranged between 8.00±1.91 and 12.00±4.95 for 238U, 8.00±1.21 and 10.00±5.43 for 232Th and 245.61±1.10 and 308.37±0.10 for 40K. The results are within globally accepted limits for natural background radiation specified by the UNSCEAR. The calculated radiological hazard indices also fell below the standard values for human safety as specified by UNSCEAR. This baseline data is essential for future comparative studies and environmental monitoring following the commencement of refinery operations. It also provides a scientific foundation for regulatory compliance and public health protection in the area.