Natural Radionuclide characterization on Baltim-El Burullus coastal sediments and their risk assessments

Abstract

The Egyptian black sand occurs especially along the beaches of northern part of the Nile Delta. Baltim-El Burullus coastal sediments lie between Longitudes 30° 10′ and 34° 15′E, and Latitudes 31° 10′and 31° 35′N. Sixty two samples from Baltim-El Burullus coastal plain were measured radio metrically by using Na-I detector for determination of 238U, 232Th, 226Ra eU and 40K concentrations. 238U concentration ranged from 1 to 5 ppm with 1.63 as an average, 232Th from 1 to 10 ppm with average 3.66 ppm, 226Ra (eU) from 1 to 6 with 1.92 as an average and 40K from 0.10 to 2.55 with average (0.76). The studied stream sediments could be intimated to different sources, leading to variability in contribution of the radioelements, thus the activity concentration of 40K > 232Th > 226Ra> 238U. eU / Ra eU ratios average (0.66), is lower than unity indicate the disequilibrium in the studied coastal sediments, suggesting disequilibrium with uranium migration out. The inter-element relations show the presence of U and Th in discrete minerals or their separate migration. The radiological hazard parameters, like the dose rate (D), the annual effective dose equivalent (AEDE), radium equivalent activity (Raeq), external (Hex), internal (Hin) hazard indices and gamma index (Iγ) were estimated for these sediments and compared with the permissible international limits. Nearly, all the studied samples are within the recommended permissible levels for most environmental parameters, with the exception of some samples lie out of the limits.