Natural Gamma Radiation in Primary Schools of Zanjan Province

Background: Environmental gamma ray refers to the gamma radiation from terrestrial sources and building materials. In enclosed spaces radiation can become a health hazard leading to potential increase in the rates of lung cancer. The goal of this study is to assess the exposure to natural gamma radiation of children in the schools of Zanjan province. Method:The natural gamma radiation was assessed in 46 primary schools of Zanjan province. A total number of 75 classrooms were studied. The measurements were performed in classrooms and schoolyards using a Geiger–Muller detector (RDS-110). Alongside radiation measurements, all the data corresponding to the characteristics of each school building were collected. Results: The results showed that the outdoor dose rate ranged from 82 to 106nSv h-1 while gamma dose rate due to inside classrooms ranged from 106 to 137nSvh-1. The findings represented that the highest indoor gamma dose rate belonged to the buildings of more than 30 years and metal frame and brick (P<0.05). Conclusion: We concluded that the effective dose due to gamma radiation from terrestrial sources and building materials for students of primary schools in Zanjan province (0.83 mSv) was higher than worldwide average of the annual effective dose (0.48 mSv).