Measurement of outdoor and indoor natural gamma background radiation and risk of cancer in residents of Kashan during 2016-2017

Natural gamma background radiation can cause ionization in vital molecules such as DNA and can have destructive effects on human health. Measurement of these radiations is very important because they increase incidence of cancers and genetic damages. The aim of this study was to measure the dose rate, annual effective dose and incidence of cancer risk in Kashan city, north of Isfahan Province. In this cross-sectional study, measurements were performed using the dosimeter of the Radiation Alert Monitor 5 Model during daylight in outdoor and indoor in five geographical regions of Kashan city (north, south, east, west and center) and in four different seasons of the year. In each geographic region, measurements were carried out at three consecutive days in the middle of each season in ten random points. Then, the annual effective dose and excess lifetime cancer risk were calculated. The mean dose rates were 155±34 nSv/h and 186±34 nSv/h in outdoor and indoor, respectively. There was no significant difference between the mean dose rate in different seasons and different geographical regions. Furthermore, the annual effective dose was found to be 1.10 mSv while the estimated excess lifetime cancer risk was 4.16×10-3. The annual effective dose arising from natural gamma background radiation (1.10 mSv) in Kashan city is much higher than the worlds' average (0.48 mSv) and the values obtained in most cities in Iran