The area under investigation is located between Rafah and Alareish cities, on the Mediterranean Sea coast, Northern Sinai Peninsula, Egypt. Ground gamma-ray spectrometric survey was conducted along equally-spaced profiles, directed N-S, on an area totaling 7.2 km2. The spacing between profiles was set at 100 m, with a station interval of 20 m and a profile length of about 900 m.
The studied black-sand beach deposits could be differentiated according to their total-count (T.C.) radioactivity into five normally-distributed interpreted radiometric lithologic (IRL) units denoted as U1, U2, U3, U4 and U5.The computed characteristic T.C. radiometric statistics of these five IRL units range from 4.67 Ur to 9.96 Ur for their individual arithmetic means. The computed arithmetic means for the three radioelements K, eU and eTh reach 0.46 % , 2.25 ppm and 6.17 ppm for the whole study area, respectively. It is clear from the application of the four statistical inference tests that only two IRL units (U3 & U4) could be considered as belonging to one and the same parent population, from the radioactivity point of view.
Concerning the study area, the mean natural equivalent radiation dose rate from terrestrial gamma-radiation attains 0.33 mSv/y. This average value remains on the safe side and within the maximum permissible safe radiation dose, without harm to the individual, except at three scattered points reaching more than 1.0 mSv/y.