Radionuclides released from nuclear power plant accidents are usually dispersed into the atmosphere as airborne radionuclides and sometimes travel at high altitudes (as in the Chernobyl accident) and eventually settle on the earth. Rainfall washes down these airborne radionuclides allowing for their accumulation in selective areas in the environment according to the soil type and topography. 137Cs is strongly adsorbed by soil particles that have a high content of clay. Although the migration of 137Cs is relatively low in the soil, its half-life is relatively long, making the long-term monitoring of its activity concentration in river water, ground water and vegetation essential; specifically in areas of known elevated levels of Cs.

Relatively large amounts of radioactive cesium have been widely detected following the most recent Nuclear Power Plant (NPP) accident in Japan. A baseline value for the radioactivity concentration in Qatari soil is crucial for further estimation of the radiation background dose and annual effective dose equivalent for individuals living in the State. Such data can also be used to assess their biological effect and behavior in the environment. With the interest in establishing this baseline, a group of scientists from the Ministry of Municipality and Environment, Qatar and University of Surrey, UK lead by Dr. Huda Al-Sulaiti, from QEERI have focused on the determination of the activity concentrations of 137Cs. Around 129 soil samples have been collected across the State of Qatar prior to the 2011 Fukushima Dai-ichi nuclear power plant accident. The work has been published in Radiation Physics and Chemistry, Elsevier.

The results of the current investigation were input into the Qatar 137Cs reference map as illustrated in the distribution map. The activity concentrations measured ranged from 0.21 to 15.41 Bq/kg, with a median value of 1 Bq/kg, the greatest activity concentration being observed in a sample obtained from northern Qatar. Although it cannot be confirmed due to the lack of data from Qatar before the accident, it is expected that this contamination is mainly due to releases from the Chernobyl accident of 26 April 1986.