Analysis of Natural Radioactivity in Phosphogypsum by Gamma Spectrometry and Evaluation of Radiological Risk Parameters Associated with Phosphogypsum Storage in Senegal

The HPGe gamma spectrometer was used to measure the concentrations of the natural radionuclides 226Ra, 232Th, and 40K in eight samples of phosphogypsum, in order to assess the health risk indices associated with radiation and the excess lifetime cancer risk (ELCR). The 226Ra, 232Th, and 40K were discovered with activity concentrations of 586.26 ± 129.91, 4.05 ± 1.47, and 12.22 ± 6.75, respectively. The average values of the estimated radiological risk parameters were 592.99 ± 141.06 Bq·kg−1 for radium equivalent (Raeq), 273.81 nGy·h−1 for the external absorbed dose rate (Dext), and 544.81 nGy·h−1 for the internal absorbed dose rate (Dint). The average annual effective dose (AEDE) was 335799.36 nSv·y−1 for the external effective dose (AEDEext) and 2672601.09 nSv·y−1 for the internal effective dose (AEDEint). The annual dose equivalent to the gonads (AGED) was 1832.32 μSv. The average cancer risk rate (ELCR) was 10.22 × 10−3. With the External Risk Index (Hext), the Internal Risk Index (Hint), the Representative Gamma Index (Iγ), and the Alpha Index Iα, the average risk indices were 1.60; 3.19; 1.98; and 2.93. According to this study, the average values of radiological risk parameters for all examined samples exceed the internationally recommended thresholds.