Natural Radioactivity and Health Risks in Southeastern Desert, Egypt: A Forensic Evaluation of Wadi Um-Sleimat, Jebel El-Erediya, and Wadi Um-Had

This study looks at the effects of radon-222 (²²²Rn) exposure in three areas of the Southeastern desert of Egypt: Wadi Um-Sleimat, Jebel El-Erediya, and Wadi Um-Had. It uses a forensic method to trace the sources of radon and assess how it affects the environment. It evaluates the external annual effective dose (EAED) and the annual effective dose from indoor exposure to ²²²Rn and its decay products (E_Rn) to understand better the health risks associated with natural radioactive activities. The findings reveal that the EAED values in Wadi Um-Had range from 0.19 to 0.49 mSv/y; while in Wadi Um-Sleimat, the values range from 0.115 to 0.191 mSv/y; and in Jebel El-Erediya, the values range from 0.160 to 0.490 mSv/y. Furthermore, the assessment of the E_Rn highlights significant risks, with Wadi Um-Had exhibiting values between 7.94 and 39.72 mSv/y, Wadi Um-Sleimat ranging from 2.82 to 8.07 mSv/y, and Jebel El-Erediya showing values from 6.33 to 40.78 mSv/y, all at a ventilation rate (v) of 0.1 air changes per hour (ACH). The ²²²Rn activity concentrations (AC_Rn) were measured, with Wadi Um-Sleimat reporting levels ranging from 112.1 ± 9.66 Bq/m³ to 320.2 ± 27.6 Bq/m³ at a v of 0.1 ACH and from 23.75 ± 2.05 Bq/m³ to 67.87 ± 5.85 Bq/m³ a v of 0.5 ACH. In Wadi Um-Had, AC_Rn ranged from 315.25 ± 27.18 Bq/m³ to 1576.24 ± 135.88 Bq/m³ at a v of 0.1 ACH and from 66.83 ± 5.76 Bq/m³ to 334.13 ± 28.8 Bq/m³ at a v of 0.5 ACH. Jebel El-Erediya exhibited AC_Rn ranging from 251.21 ± 21.66 Bq/m³ to 1618.11 ± 139.49 Bq/m³ at a v of 0.1 ACH and from 53.25 ± 4.59 Bq/m³ to 343 ± 29.57 Bq/m³ at a v of 0.5 ACH. The evaluation of surface ²²²Rn gas exhalation rates (EXR_s) indicates moderate emissions in Wadi Um-Sleimat (6–17.2 Bq/m² h), significantly higher emissions in Jebel El-Erediya (up to 84.80 Bq/m² h), and lower emissions in Wadi Um-Had (13.52–87.05 Bq/m² h). Finally, the excess lifetime cancer risk (ELCR) values indicate a moderate risk in Wadi Um-Sleimat (0.42 × 10⁻³ to 0.71 × 10⁻³), a higher risk in Jebel El-Erediya (up to 1.73 × 10⁻³), and varied risk levels in Wadi Um-Had (0.67 × 10⁻³ to 1.70 × 10⁻³). This study highlights the importance of forensic evaluations of ²²²Rn levels to trace its sources and release patterns, alongside implementing mitigation strategies to protect public health. The findings contribute to guiding health policies for the public, environmental management, and developing safety guidelines for mining and residential zones.