Estimation of radiological hazards to lungs and some organs due to soil gas radon, thoron, and their progeny using CR-39 polymer detector in Kadhimya, Baghdad, Iraq

Abstract

Naturally occurring radioactive gases like radon and thoron in soil are well known to impact air quality, influencing the resident’s health in that area. This work measured radon and thoron concentrations in soil and the associated radiation hazard indices using CR-39 detector in Kadhimya, Baghdad, Iraq. The mean radon and thoron concentrations in the area under study were determined to be 295.06 ± 4.00 and 1557.2 ± 29.23 Bq/m³, respectively. The average indoor and outdoor annual effective dose, the excess lifetime cancer risk, and lung cancer cases per year per million people due to radon were found to be 7.44 ± 0.10 mSv/y\(,\) 1.86 ± 0.03 mSv/y, 3.58 ± 0.05, and (167.49 ± 2.27\()\times {10}^{-6}\), respectively, and due to thoron, they were found to be 39.29 ± 0.74 mSv/y, 9.82 ± 0.18 mSv/y, 18.91 ± 0.35, and (883.94 ± 16.59\()\times {10}^{-6}\), respectively. The average annual effective dose to lungs due to exposure to radon was estimated to be 148.88 ± 2.02 mSv/y. The average effective dose in tracheobronchial and pulmonary + pulmonary lymph region, and the effective dose in lungs were found to be 8.93 ± 0.12 mSv/y, 8.93 ± 0.12 mSv/y, and 17.87 ± 0.24 mSv/y, respectively. The total effective equivalent dose caused by radon, thoron, and their progeny tissues ranged from 5.62 to 49.45, with an average value of 15.60 mSv/year. All the evaluated radiation hazard indices exceeded the recommended limits of radiation protection agencies. Radon and its progeny contribute about (44%) to the total annual inhalation dose, whereas thoron and its progeny contribute about (56%) to the total annual inhalation dose. The surpassing of recommended radiation hazard limits for radon and thoron highlights the need for regulatory actions and public health interventions.