Preliminary Assessment of Indoor Radon Concentration and the Associated Health Risk to the Dwellers Surrounding Minjingu Phosphate Mine

Abstract

Radon is a radioactive gas and a decay product of uranium. This gas poses a potential health risk to humans. This study aimed to assess preliminary indoor radon concentration at homes in Minjingu village and use the results of measurements to estimate the annual effective dose received by the dwellers and the associated excess lifetime cancer risk.  The measurements were conducted in selected 22 houses using Professional Radon gas Monitor, AlphaGUARD from the Tanzania Atomic Energy Commission Laboratory. Results indicated that the radon concentration ranged from 33±4 Bq/m3 to 1080 ±57 Bq/m3 with the mean of 161±12 Bq/m3. The inhalation dose ranged from 0.8mSv.y-1 to 27.2 mSv.y-1 with the average of 4.1 mSv.y-1. The excess lifetime cancer risk (ELCR) ranged from 0.3 to 10.5%, with the average of 1.6%. Since some of the observed readings in this study are higher than the recommended levels of 300 Bq/m3, it is recommended to improve the ventilation system of the houses. Also, the long-term measurement of radon in this area is recommended in order to take into consideration the long-term variation of meteorological parameters such as temperature, relative humidity and pressure which are known to affect indoor radon levels. Regulatory measures for the areas with elevated levels of radon should be implemented, and a public health campaign to provide awareness about the effects of radon and its mitigation in homes should be given to the dwellers.