Hazardous parameters associated with natural radioactivity exposure from black sand

Black sand samples collected from Baltim beaches (Kafr El-Sheikh governorate) in Egypt on the Mediterranean Sea shore were analyzed radiometrically and evaluated using a nondestructive gamma ray spectroscopic techniques. The natural radionuclides of 226Ra, 232Th and 40K in the black sand samples were identified and quantified. It is found that the activity concentrations for 226Ra, 232Th and 40K in different eleven sites (S1S11) were found within the ranges of 28–322, 91–308 and 81–339 Bq/kg, respectively. Moreover, different radiological hazardous parameters (absorbed dose rate, annual effective dose equivalent, radium activity, annual gonadal dose equivalent and excess lifetime cancer risk) were calculated. The results show that these values are greater than the permissible values due to increasing the activity concentrations of the primordial radionuclides 226Ra, 232Th and 40K. The dose rate for radiation emitted at 1 m from the surface of land was measured directly and the results shown that all sites emit radiation doses more than the international permissible value (57 nGy/h) especially at three sites which around 340 nGy/h. These values are important to establish baseline levels of this environmental radioactivity to detect any upcoming change for the local population and resorts people. The relatively high dose rate will be considered as a spa for the physical therapy such as treatment of some skin diseases and rheumatoid. [Display omitted] •Radioactivity of 226Ra and 232Th was >UNSCEAR (2008) limits, while 40K was not.•Most hazard indices of black sand samples are high compared to permissible value.•Annual effective dose equivalent (Dannu) in all sites was below 1 mSv/y.•Value of ELCR and AGDE for all samples was high than the safe limit.•Radioactivity of black sand deposits in Baltim beaches should be evaluated regularly.