Radioactivity of sand, groundwater and wild plants in northeast Sinai, Egypt

The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km(2) in northeast Sinai, Egypt, were investigated by gamma-ray spectroscopy. Moderately significant correlations among U-238, Th-234, and Ra-226 isotopes and low significant correlations between the concentrations of U-238-series and Th-232 in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for Ra-226, Th-232, K-40, and Cs-137, respectively. The range of concentrations of Ra-226, Th-232, and K-40 in water samples collected from five wells were <0.4-0.16, <0.4-0.13, and <0.15-1.62 Bq 1(-1), respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h(-1). The Ra-eq activities of the sands are lower than the recommended maximum value of 370 Bq kg(-1) criterion limit for building materials.