Activity size distributions of radioactive airborne particles in an arid environment: a case study of Kuwait.

Atmospheric radioactive airborne released from several natural and artificial sources can travel for long distances and disperse in different directions. Both the physical and chemical characteristics of the atmospheric aerosols control this movement. The concentrations of 210Pb, 210Po, 7Be, 40K and 137Cs radionuclides in the ground surface air were determined in three particle sizes (2.4-10.2, 0.73-2.4 and less than 0.73 μm). High-volume air samples were collected from five different locations representing the five governorates of Kuwait using high-volume air samplers connected to a five-stage cascade impactor. The radioactivity concentrations of almost all fallout radionuclides were concentrated on the fine particle size fractions. The cosmogenic 7Be radioactivity level in all locations was relatively comparable and varied between 1.16 and 18.38 mBq/m3, with a geometric mean value of 6.80 mBq/m3. 137Cs was infrequently recorded with concentration varied between 4 and 14.3 μBq/m3. The geometric mean levels of the 210Po and 210Pb were 0.899 mBq/m3 and 1.03 mBq/m3, respectively, indicating that anthropogenic sources likely enrich 210Po. 40K was concentrated on large particle size fractions with a geometric mean value of 2.34 mBq/m3, reflecting the effects of the local dust sources. It was concluded that the radiological hazards due to airborne radioactive inhalation are low and can be negligible, where the annual estimated effective dose is about 64.0 μSv. The radioactive airborne measurements compose the base of estimating the aerosols residence time, resuspension rate of dust, soil redistribution and source apportionment, particularly the 210Pb and 210Po radionuclides.