Assessing radioactivity levels in agricultural soil: a comparative study of traditional vs. modern fertilization techniques in Tunisian oases

To establish a radiological national reference for agricultural soil across Tunisian oases and assess the risk to human health associated with date consumption, with a focus on comparing the impact of traditional and modern fertilization, radiological parameters and activity levels of ²²⁶Ra, ²³²Th, and ⁴⁰K were determined for 27 oases. These oases were located in three southern Tunisian governorates. The activity concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K was measured using a 3 × 3 inch NaI(Tl) scintillation detector, which was found to be 21.82 ± 1.0 \({\text{Bq kg}}^{-1}\) ${\text{Bq kg}}^{-1}$ , 26.51 ± 1.1 \({\text{Bq kg}}^{-1}\) ${\text{Bq kg}}^{-1}$ , and 559.21 ± 23.0 \({\text{Bq kg}}^{-1}\) ${\text{Bq kg}}^{-1}$ , respectively, for traditional oases and 26.56 ± 1.2 \({\text{Bq kg}}^{-1}\) ${\text{Bq kg}}^{-1}$ , 24.45 ± 1.1 \({\text{Bq kg}}^{-1}\) ${\text{Bq kg}}^{-1}$ , and 661.28 ± 26.3 \({\text{Bq kg}}^{-1}\) ${\text{Bq kg}}^{-1}$ , respectively, for modern oases. In addition, ambient dose equivalent rate was measured during sampling using a multipurpose hand-held radiation CsI(Tl) detector, which was found to be 0.075 µSv/h in traditional oases and 0.078 µSv/h in modern oases. The resulting radiological parameters and activity concentrations were then compared to results from neighboring countries and the average soil activity worldwide.