Radiological impacts of the usability of Dolerite and Kaolin as raw materials for construction works in Abia State, Nigeria

This research study is aimed at carrying out radiometric analyses of the natural radioactivity resulting from the presence of radionuclides in dolerite and kaolin which are raw materials widely used in construction works. The activity concentrations of the identified natural radionuclides of 226Ra, 228Ra and 40K in 40 samples of these solid minerals collected from 4 mining sites were determined by gamma ray spectroscopic technique using a well calibrated [NaI(Tl)] detector. The mean values of the activity concentrations of 226Ra, 228Ra and 40K for the dolerite samples were found to be 10.989Bq/kg, 6.956Bq/kg, 723.253Bq/kg and 10.735Bq/kg, 6.175Bq/kg, 714.895Bq/kg respectively (for the 2 dolerite mining sites); and for the kaolin samples, 8.507Bq/kg, 7.33Bq/kg, 87.511Bq/kg and 8.416Bq/kg, 7.354Bq/kg, 86.727Bq/kg respectively (for the 2 kaolin mining sites). The radium equivalent activity, the absorbed dose rate, the equivalent dose rate, the external and internal hazard indices, the annual outdoor and indoor effective dose rates were computed and compared with international radiological standards to ascertain if these minerals pose any radiological hazard. The results obtained were found to conform within the limits of acceptable international radiological standards and may not pose any immediate threat to the public and users of these two solid minerals for construction works.