Estimation of External Natural Background Gamma Rays Doses to the Population of Caspian Coastal Provinces in North of Iran

Abstract

The effect of natural background radiation on health is still challenging. However, it is cleared that it depends on dose received by population. The estimation of external natural background gamma rays doses to the population of Caspian coastal provinces in north of Iran was the main goal of study. Gamma rays was measured using calibrated radiation survey meter in random 51 urban and rural health centers to estimate the exposure to population (Total population = 6888118 persons) in residential areas of Gilan, Mazandaran and Golestan ( Total area 59240 Km² ) as Caspian coastal provinces in north of Iran. Results showed that the average dose rate in the area under study is about 60.37±14.88 nSv/h or 0.53 mSv/yr (Range 30 to 90 nSv/h or 0.26 to 0.79 mSv/yr). The data from Ramsar is excluded from the estimation because of a very high natural background radiation found in that area (Max. 240 mSv/yr). No significant difference was found between the doses of the provinces (P=0.237). The external natural background gamma rays doses to the population of Caspian coastal provinces in north of Iran was found to be nearly equal to the average value in the world (0.5 mSv/yr). Further national studies are suggested.