Radionuclides measurements and mineralogical studies on beach sands, East Rosetta Estuary, Egypt

Radiometric measurements were carried out for the beach sands from East Rosetta estuary to determine the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K, using a Hyper Pure Germanium spectrometer, to estimate the dose rates and radiation hazard indices. The average specific activities are 778.20 Bq/kg for ²³⁸U; 646.89 Bq/kg for ²²⁶Ra; 621.92 and 627.85 Bq/kg for the ²²²Rn daughters ²¹⁴Pb and ²¹⁴Bi respectively. The average specific activity of ²³²Th is 1510.25 Bq/kg, while the calculated specific activity for ⁴⁰K has an average of 8.41 Bq/kg. The average specific activity of ²³⁵U is 38.61 Bq/kg. The average absorbed dose rate is 1211.36 nGy/h, 20 times higher than the estimated average global primordial radiation of 60 nGy/h and 6 times higher than that of the world range (10–200 nGy/h). The radium equivalent (Ra_eq) values are from 6 to 9 times the recommended value. The internal and external hazard indices (H_int, H_ex) indicate that their values are from 6 to 11 times the permissible values of these indices. These higher values may be due to the presence of economic heavy minerals containing radionuclides as zircon and monazite as well as some trace minerals, thorite and uranothorite. The mineralogical study indicates the beach sands contain heavy minerals, zircon, monazite, rutile, ilmenite, leucoxene, magnetite and garnet. The average abundance of zircon is 0.175 wt% ranging from 0.125 wt% to 0.239 wt%, while it is 0.004wt% ranging from 0.001 wt% to 0.007 wt% for monazite. The average abundance is 0.087 wt% for rutile; 2.029 wt% for ilmenite; 1.084 wt% for magnetite; 0.384 wt% for leucoxene and 0.295 wt% for garnet.