Assessment of natural radionuclides and their radiological hazards in commercial granite produced in Xinjiang,China

ABSTRACT

The specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K of 26 samples of granite produced in Xinjiang of China were measured by a high-purity germanium detector, and their radiological hazards of radium equivalent, external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index were evaluated. The results indicate that the overall average specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K obtained in the investigated samples are below the world’s average granite values. The average radium equivalent is within the recommended limit of 370?Bq?kg^?1. The results obtained further show that the mean values of external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index are 0.65, 0.77, 111.7?nGy?h^?1, 0.55 mSv?y^?1, 0.89 and 0.23, respectively. These mean values established that radiological hazards are also found to be below the international recommended values. The results are compared with granite samples from other countries or China-Taiwan province. It can be noticed that the specific activity values of granite samples produced in China are lower or similar to that of other countries or China-Taiwan province, however there are higher specific activity values for ²²⁶Ra and ²³²Th in individual samples, which need to provide proper radiation monitoring before use considering the long term health effect.