Radiological Characterization of Settled Dust during a Severe Dust Episode in Jordan

An unusually massive dust storm influenced Jordan and neighboring countries on September 8th to 11th 2015. The dust from this storm was investigated for its radioactive content using gamma-ray spectroscopy. Such storms may carry a large amount of dust and radioactive content, which may impact human health. Samples were collected from different regions in Jordan. The activity concentrations of natural Th-232 (Thorium), U-238 (Uranium), K-40 (Potassium) and artificial Cs-137 (Cesium) radionuclides were measured. The activity concentrations (Bq kg(-1)) had an average of (+/- Standard Deviation (SD)) 24.7 +/- 10, 34.1 +/- 13.3, 438 +/- 124 and 15.7 +/- 4.1 for Th-232, U-238, K-40, and Cs-137, respectively. The activity concentrations of natural and artificial radionuclides were analogous with results obtained from different studies with seasonal storms. The natural radionuclides were comparable to what was found in the local soil, while the activity concentration of Cs-137 was larger than that found in soil (2.4 +/- 1.2 Bq kg(-1)) and this is attributed to particle size effects. Dose assessment of Cs-137 showed that it does not contribute significantly to the internal dose of a human during inhalation. The correlation between Th-232 and K-40 activity concentration in the measured dust particles is a moderate correlation with a value which is in agreement with those found in other studies worldwide.