Indication of the radioactive fallout in Riyadh, Saudi Arabia following the Fukushima nuclear accident

• First evidence of Fukushima radioactive fallout in Riyadh, Saudi Arabia has been confirmed in April 8, 2011.
• The airborne fission products 131I, 134Cs and 137Cs were measured in air samples.
• The radionuclide concentrations were determined by identifying their characteristic gamma rays.
• Their activity concentrations were studied as a function of time over a period of 20 days.

On March 2011, a severe damage has occurred to Fukushima Di-iachi nuclear reactor complex in Japan following the huge earthquake and the resulting Tsunami. Consequently, vast amounts of radioactive fallout were released into the atmosphere and contaminated the environment in Japan. Soon after the accident, traces of anthropogenic radionuclides were detected in environmental samples collected in many parts in the northern hemisphere even very far away from Japan creating a global concern. There is no information about radioactive contamination in the Arabian Peninsula caused by the Japanese Fukushima nuclear accident. The first evidence of Fukushima radioactive fallout in Riyadh (24° 43′ N, 46° 38′ E), Saudi Arabia has been confirmed in April 8, 2011. The airborne fission products 131I, 134Cs and 137Cs were measured in air samples. The radionuclide concentrations were determined by identifying their characteristic gamma rays using a germanium detector. Their activity concentrations were studied as a function of time over a period of 20 days at the end of which they had mostly fallen below our limit of detection. The maximum activity concentration of 131I, 134Cs and 137Cs in air of, respectively, 323.7 ± 18.5, 17.2 ± 1.0 and 26.0 ± 1.8 μBq m−3 were observed on April 10–11, 2011. The 131I/137Cs and 134Cs/137Cs activity ratio values in air were presented and discussed. Finally, the effective doses to the public of Riyadh city from inhalation of 131I, 134Cs and 137Cs due to contribution from Fukushima incident was found far below levels of concern.