Health risk assessment of thoron concentrations in external and internal materials samples used by newborns in Iraq

One of the most important radioactive gases in the thorium series is thoron ( 220 Rn). However, it has received less scientific attention compared to radon ( 222 Rn), despite its potential health risks, particularly in vulnerable populations such as newborns. This study aims to compare thoron concentrations in a range of materials commonly used for newborns. 220 Rn concentrations were determined for 120 samples of external materials like (care product) and internal materials like (milk, healthy water, and liquid drugs) used by newborns in Najaf governorate that are available in pharmacies and hospitals. Measurements were done using CR-39 track detectors. Also, some of the radiological risks due to inhalation or ingestion of 220 Rn concentration, such as annual effective dose (AED inhalation and AED ingestion ), Lung Cancer Case (LCC), and Excess lifetime Cancer Risk (ELCR) were calculated. The results of 220 Rn concentrations in the external samples ranged from 4.23 Bq/m 3 to 77.47 Bq/m 3 , with an average of 27.19 Bq/m 3 , while, the results of 220 Rn concentrations in internal samples ranged from 1.49 Bq/m 3 to 49.82 Bq/m 3 , with an average value of 18.34 Bq/m 3 . Also, the results of the radiological risks due to inhalation, such as AED inhalation and LCC × 10 −6 , ranged from 0.02 to 0.29 mSv/y and from 0.29 to 5.28 mSv/y, respectively. The range values of the radiological risks due to ingestion, such as AED ingestion and ELCR × 10 −6 , were 0.0001–0.64 mSv/y and 0.0002–2.47, respectively. Results of 220 Rn concentrations in the present work were within the safe limit according to ICRP (International Commission on Radiological Protection). Thus, studied samples of external and internal materials used by newborns in Najaf governorate were found to be safe.