Natural radiological hazardous of rocks in Duhok governorate, Kurdistan region, Iraq

الملخص EN

We performed a study over the radiological impact on nine samples of natural rocks collected from various areas in the Duhok governorate.

The governorate is located in the northwest Kurdistan region of Iraq.

NaI(TI) gamma ray spectrometer for 30000 sec per sample was utilized to detect the concentration of radionuclide in rocked samples.

The average activity concentration values of 226Ra, 232Th and 40K obtained are 13.10 Bqkg-1, 5.20 Bqkg-1 and 134.32 Bqkg-1 respectively.

Gray Clay stone, Limestone, Fine sand, Silty clay and Marley shows relative high activity concentration whereas Chalky Limestone show low activity concentration while other rock formations were moderate in radioactivity level.

By utilizing the standard analytical method the excess life time cancer risk and hazard indices were estimated.

The average values obtained for absorbed dose, annual effective dose equivalent (Indoor, Outdoor), hazard indices (external, internal), excess lifetime cancer risk, representative (alpha, gamma) indices and radium equivalent are respectively 14.88 nGyh-1, 73 μSvy-1, 18.26 μSvy-1, 0.084, 0.120, 0.064×10-3, 0.115, 0.07 and 31 Bqkg-1.

After the values which obtained in this work are compared with corresponding world permissible values, it found that the values located below the standard limits for such environments.

The rock from the study area provided no excessive exposure for the inhabitants and can be utilized as building material without posing any radiological threat or harm to the public users.