Assessment of Natural Radioactivity Concentration and Radiological Risk in Tanjung Enim’s Coal Mine, South Sumatra Indonesia

Abstract

Environmental radioactivity analysis has been carried out to determine the level of environmental radioactivity and the potential radiological hazards at Tanjung Enim’s coal mine. Gamma spectroscopy method has been carried out to identify radionuclides and their types of activity. The results of radionuclide concentration are used to determine the radiological hazard index and become input data for the Residual Radioactivity Onsite 7.2 application to determine the dose rate and long-term cancer potential received by workers in coal mines. The results obtained for the average concentration of radionuclide activity in coal samples are 226Ra, 232Th, and 40K are 72.468 Bq/kg, 86.905 Bq/kg, and 1802.049 Bq/kg, respectively. While the soil samples 226Ra, 232Th, and 40K respectively 79.205 Bq/kg, 100.209 Bq/kg, and 1443.275 Bq/kg. The radionuclide concentrations of both samples exceeded the UNSCEAR and worldwide reported averages for coal and soil. The average radiological hazard index for coal samples, namely Raeq, Hin, and Hex, was 335.500 Bq/kg, 1.102, 0.906, respectively. While the soil samples were 333.636 Bq/kg, 1.115, and 0.901, respectively. The index parameter is already lower than the UNSCEAR recommendation except for Hin, so there is a potential radiological hazard in internal pathways such as respiratory and digestive organs for mining workers. The total annual effective dose rate based on 5 RESRAD-Onsite 7.2 pathways, namely external gamma, inhalation, radon, soil ingestion, and drinking water, is 1.675 mSv/year, exceeding the dose limits determined by ICRP, 1 mSv/ year. The ELCR is 6.625×10-3 which exceeds the UNSCEAR recommendation, 2.4×10-4. Based on the results, it is necessary to intervene in the mining environment of the Tanjung Enim’s coal mine.