The study of natural and anthropogenic radioactivity in sand samples using gamma spectrometric analysis

Gamma ray spectrometry was used to analyze the radioactivity concentration of radioisotopes such as uranium, thorium, and potassium in the sand samples collected from River Cauvery. The particular range at the gravel, medium sand to fine sand with particle size greater than 125 microns was separated using the American Society for Testing Materials standard sieve. An electromagnet was used to part the amagnetic samples from the magnetic substances existing in the sand of the river. The radioactive isotopes and associated parameters such as the absorbed doses (D_in and D_out) and annual effective doses (AE_in and AE_out) were evaluated. Internal (H_in) and External (H_out) Hazard Index, Radium Equivalent (Ra_eq), Internal (ELCR_in) and External (ELCR_out) Excess Lifetime Cancer Risks, Gamma (I_g) and Alpha (I_α) index, Activity Utilization Index (AUI), and Radioactive Heat Production (RHP) were also calculated and correlated. The average radioactivity of uranium, thorium, and potassium radioisotopes is 2.58, 8.06, and 248.26 Bq/kg, respectively, for greater than 125 microns and 2.71, 11.63, and 170.25 Bq/kg, respectively, for amagnetic grains. All these results were referred to the global standards, and it was found that all the parameters were within the limits. Howsoever, there was an exception in site 31; the rest of the sites were safe for use in the agriculture and construction industry and free from radiological risk.