Assessment of radiological risk factors in the Zonguldak coal mines, Turkey

Radon concentrations in the working sections of the Zonguldak coal mines were determined and activity concentration measurements of natural ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides were performed with high resolution passive gamma-ray spectrometry for coal samples collected from these sections. The ²²²Rn concentration was found to be between 15 and 78Bq m^-3, well below the action limit of 1000Bq m^-3 according to ICRP65. The annual effective dose to miners due to inhalation of radon was determined to be between 60 and 312 μSv. Activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the coal samples were found to be 13-164, 13-215 and 344-1100Bq kg^-1, respectively. Radium equivalent activity, dose rate in air and average annual effective dose equivalents were calculated in the range of 66-602Bq kg ^-1, 32-265nGy h^-1 and 30-244 μSv, respectively. The resultant total annual effective doses can be used to minimise the radiological risk to the coal miners.