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

Abstract

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 232Th (Thorium), 238U
(Uranium), 40K (Potassium) and artificial 137Cs (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 232Th, 238U, 40K, and 137Cs, 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 137Cs
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 137Cs showed that it does not contribute significantly to the
internal dose of a human during inhalation. The correlation between 232Th and 40K 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.

Keywords: Radioactivity, Gamma -ray spectrometry, Cesium-137, Unseasonal dust.

PACS number: 29.30.Kv.