Radiological Baseline Assessment of a Naturally Occurring Radioactive Material (NORM) Waste Disposal Facility in Ghana

Knowledge of accurate radio-isotopic signatures of NORM waste disposal site is essential prior to the disposal, to ascertain the baseline radioactivity levels. In this work, soil and water from a NORM waste site situated at Sofokrom in the Sekondi-Takoradi Metropolis of Ghana is characterized and determined. The mean activity concentration of 226Ra, 232Th, and 40K measured in the soil samples are 40.31 ± 13.93 Bq/kg, 63.29 ± 23.18 Bq/kg, and 198.71 ± 49.10 Bq/kg, respectively, with the 226Ra and 232Th average values being higher than the average worldwide values by UNSCEAR. Also, the average activity levels of water samples from monitoring borehole measured for 226Ra and 232Th are within the WHO guidance levels of 1 Bq/L. The radiological parameters such as internal and external hazard indices (Hin and Hex), absorbed dose rate (D), and radium equivalent activity (Raeq) are estimated to assess the radiological risk to human, and compared with other similar works.  Except for the annual gonadal dose, the remaining parameters are less than the recommended values. Multivariate statistical analysis is done to establish the interrelations among the activity concentrations of the radionuclides and their radiological parameters using Pearson correlation coefficient and principal component analysis. Strong positive correlations between 226Ra, 232Th, and the radiological parameters are observed. These findings would serve as the reference point for assessing future variations in the background radioactivity level owing to the geological or human activities from the disposal of the oil waste in the environment, as well as to aid in improving the technical foundations for the management of the NORM waste.