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Abstract
The results of this systematic investigation of 120 km along the North Sinai coast establish the existence of a wide range of variation in the 226Ra and 232Th series activities, which is attributable to the existence of BS in some locations. It is remarkable that the activity concentrations of 226Ra, 232Th and 40K in dune sand are low compared with the corresponding quoted values for sand or soil. This is also true for beach sand samples except for some sites that contain BS. The results indicate that the activities of the products of the 232Th and 226Ra series in samples obtained from the harbor area of AI-Arish city, AI-Massaid and the Zaranik protected area are higher than those from other sites. The only possible correlation between the activity contents and the sand . b 238U 226R d 232Th d . . +. . 200 c aractenstlcs was t at etween , a an , an gram sIze lractlon ~m in beach. The activities of 226Ra and 232Th were strongly correlated in both types of sand and their ratio was close to unity; 0.98 in beach and 1.04 in dune sand. On the other hand, the activities of 40K and 226Ra (or 232Th) in beach sand show evidence of anti-correlation. The dependence of the contents of different isotopes on the grain size of the samples was measured. Although the variation of NORM concentrations with grain size are different in beach and dune sand, samples with grain size 200 ~m in both cases were found to have the highest level of activity. In the case of beach ’sand, it is attributed to the high content of black colored sand. The large grain size (500 ~m) of beach sand is very poor in NORM activities.