Distribution of natural radionuclides and assessment of the associated hazards in the environment of Marsa Alam-Shalateen area, Red Sea coast, Egypt

Abstract

Radiological aspects of water, soil and shore sediments resources in Marsa Alam-Shalateen area, Red Sea coast, Egypt, were investigated with the aim of presenting background about the radiological levels and assessing the associated hazards. The results of study are intended to support the governmental authorities as regards the future-natural resources management. Sixty nine environmental samples (30 water, 33 soil and 6 shore sediments samples) were collected in 2015 and analyzed for Ra-226 (U-238) series, Th-232 series, K-40 and Cs-137 radionuclides using Hyper-Pure Germanium (HPGe) detector. For all samples, the activity concentrations of Cs-137 radionuclide are under the detection limit of the used analytical procedures. As regards the water resources, the Th-232 activity concentrations in the major part of water samples were under the detection limit. The Ra-226 activity concentrations ranged from <0.7 to 7.6 Bq L−1 and from <0.7 to 6.31 Bq L−1 for groundwater and sea water samples, respectively. All the desalinized water and 50% from wastewaters were clear of Ra-226 activity concentration. The K-40 ranged from <3 to 32.84 Bq L−1, from <3 to 38.17 Bq L−1, from <3 to 54.31 Bq L−1 and from <3 to 40.91 Bq L−1 for groundwater, sea water, desalinized water and wastewater samples, respectively. Radiologically, all fresh waters, safe for drinking except Al Gaheliya well showed Ra-226 activity concentration higher than the guidance level recommended by the WHO.For soil cover, the average activity concentrations of Ra-226, Th-232 and K-40 of the carbonaceous soil samples were 18.45, 16.78, and 334.35 Bq kg−1, respectively. While for the siliceous soil samples, they were 10.24, 8.68 and 234.47 Bq kg−1, respectively. For shore sediment samples having calcareous nature, the average concentrations of Ra-226, Th-232 and K-40 were 10.76, 9.86 and 304.74 Bq Kg−1. There are no risks for people health based on the calculated radiological hazard indices. However, people could be affected by radiation in one site (Marsa Alam-Shelateen Road km 33), where the representative level index (1.052 Bq kg−1) and absorbed gamma dose rate (66.5 nGy h−1) exceed the maximum permissible limits.