Soil radioactivity levels, radiological maps and risk assessment for the state of Kuwait. (July 2016) - Alazemi, N.
Abstract: An evaluation of the radioactivity levels associated with naturally occurring radioactive materials has been undertaken as part of a systematic study to provide a surface radiological map of the State of Kuwait. Soil samples from across Kuwait were collected, measured and analysed in the current work. These evaluations provided soil activity concentration levels for primordial radionuclides, specifically members of the 238 U and 232 Th decay chains and 40 K which. The 238 U and 232 Th chain radionuclides and 40 K activity concentration values ranged between 5.9 ↔ 32.3, 3.5 ↔ 27.3, and 74 ↔ 698 Bq/kg respectively. The evaluated average specific activity concentrations of 238 U, 232 Th and 40 K across all of the soil samples have mean values of 18, 15 and 385 Bq/kg respectively, all falling below the worldwide mean values of 35, 40 and 400 Bq/kg respectively. The radiological risk factors are associated with a mean of 33.16 ± 2.46 nG/h and 68.5 ± 5.09 Bq/kg for the external dose rate and Radium equivalent respectively. The measured annual dose rates for all samples gives rise to a mean value of 40.8 ± 3.0 μSv/y while the internal and internal hazard indices have been found to be 0.23 ± 0.02 and 0.19 ± 0.01 respectively. Highlights: Measurements made using high-resolution gamma-ray spectrometry for activity concentrations of 238 U, 232 Th and 40 K involving 184 analysed soil samples. The distribution of 40 K is observed to remain rather constant across the entire region of Kuwait. Results obtained indicate higher 238 U/ 232 Th ratio in the northern region relative to southern one. Measured radiological risk factors across the wider Kuwait environment are below world mean values.