Radiological dose assessments of fish samples due to the presence of NORMs at oil-rich areas of South Africa

Abstract

This study was conducted to estimate natural radionuclide contents in 24 fish samples collected from rivers of South Africa’s oil-rich and non-oil-rich areas. Also, the radiological analysis was performed to assess the effect of radiation on the population that consumed these fish. A high-resolution Hyper Pure Germanium (HPGe) detector was used to conduct the gamma-ray measurements. The mean activity concentrations for the selected fish samples from the examined areas for 238U, 232Th, and 40K ranged from 8.60 ± 2.97, 4.26 ± 1.18, and 105.66 ± 47.77 for the Bree; 8.06 ± 3.64, 4.84 ± 2.00, and 126.88 ± 47.30 for Klein-Brak; 8.30 ± 3.64, 3.48 ± 1.44, and 90.42 ± 29.35 for Bakens; and 6.48 ± 2.05, 5.26 ± 1.79, and 78.38 ± 20.55 for uMngeni rivers. The annual effective ingestion dose ranged from 0.050 (Argyrosomus japonicus) to 0.100 (Lichia amia) for the Bree; 0.033 (Pomadasys commersonnii) to 0.118 (Pomatomus saltatrix) for Klein-Brak; 0.034 (Enteromius pallidus) to 0.090 (Anguilla marmorata) for Bakens; and 0.046 (A. marmorata) to 0.082 (Hypseleotris cyprinoides) for uMngeni river, respectively. Also, the estimated values for the annual equivalent dose of gonads, bone marrow, and bone surface cells due to ingestion of fish samples ranged from 58.77 to 127.27 for Bree; 42.14 to 125.94 for Klein-Brak; 39.34 to 84.97 for Bakens; and 54.54 to 71.97 for uMngeni rivers (control), respectively. The activity concentrations and radiological dose estimates reported for the studied areas were within the values recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation. Hence, the result of the activity concentrations in the selected fish samples at the time of this study does not pose a radiological risk. The results could also be used as reference data for radioactivity pollution in the study area.