Assessment of health risk associated with natural gamma dose rate levels and isodose mapping of Jordan

Abstract

As a pioneering study in Jordan, an extensive measurement for external gamma dose rate (GDR) was conducted. A portable gamma radiation detector was used to perform these measurements at 1 m above the soil surface. A geographical positioning system Garmin was used to record a total of 823 measured points. The GDRs’ measurement ranged from 35 to 470 nGy h −1 giving a mean value of 90 nGy h −1 , which was found to be one and half times higher than the world average of 59 nGy h −1 . The lowest mean GDR 72 nGy h −1 was found in the Albalqa governate, while the highest mean GDR 131 nGy h −1 was found to be for the Alkarak governate. The mean annual effective dose was found to be 0.551 mSv, which is higher than the world average value of 0.48 mSv. This is a pivotal study evaluating the risks associated with GDR levels in Jordan that were the relative excess lifetime cancer risk, the mean collective effective dose, the mean weighted GDR and the mean lifetime dose that are 2.24 × 10 −3 , 5538manSv y −1 , 0.531 mSv and 39 mSv, respectively. The cosmic rays mean GDR was determined to be 20 nGy h −1 . This study focuses on constructing GDRs’ baseline data in Jordan, which will be used to determine the possible change in the natural radiation due to other human activities in the future. ArcGIS software was employed to generate an isodose map to characterise exposure rates caused by GDR in Jordan.