Annual effective dose from environmental gamma radiation in Bushehr city

BACKGROUND: Present study was an attempt to measure outdoor and indoor gamma dose rates in Bushehr city to determine corresponding annual effective dose and, to assess effect of active nuclear power plant located in Bushehr city on background radiation level of this city. METHODS: All measurements were performed by G.M (Geiger Muller) detector (X5C plus) calibrated in Iran Atomic Energy Agency. In order to avoid effects of ground on outdoor and indoor measurements, G.M detector was placed one meter higher than ground level. Also, during the outdoor measurements, G.M detector was used at least six meters away from the walls of any building nearby to avoid unwanted effects of the materials used in the buildings on measurements. RESULTS: Average gamma dose rates of outdoor and indoor measurements were determined as 51.8 ± 8.8 nSv/h and 60.2 ± 7.2 nSv/h, respectively. Annual effective dose due to background gamma radiation was calculated as 0.36 mSv which was lower than average global level. CONCLUSIONS: The average annual effective dose from background gamma radiation in Bushehr city was less than global level. Comparison of the results of present study, as follow up, with previous attempt performed in 2004 to determine effective dose of environmental gamma radiation in Bushehr province revealed that, during eight years, nuclear power plant located in this city has not significantly increased level of annual effective dose of Bushehr city.