Current activity concentrations of Ra, Th, K and Cs in beach sand samples from various coastal regions of Türkiye and associated health risk assessment.

In this study, gamma-spectrometry was used to determine the concentrations of Ra, Th, K, and Cs radioactivity in surface beach. Samples were collected from thirty-one coastal beaches across various cities in Türkiye. The results obtained were evaluated in the context of four geographical regions: Black Sea, Mediterranean, Marmara and Aegean. In all samples, the maximum, minimum, and mean activity concentration values were 66.06 ± 0.89, 1.07 ± 0.10, and 11.65 ± 0.39 Bq kg for Ra; 43.04 ± 1.21, 0.76 ± 0.10, and 7.35 ± 0.41 Bq kg for Th; and 657.39 ± 6.57, 27.54 ± 1.30, and 260.31 ± 4.06 Bq kg for K, respectively. The maximum, minimum and mean activity concentration values of the anthropogenic Cs isotope were 6.53 ± 0.25, 0.3 ± 0.05 and 2.38 ± 0.17 Bq kg, respectively. The average values of radiological hazard indices such as equivalent radium activity, external(internal) hazard index, outdoor absorbed gamma dose rate and annual effective dose equivalent were calculated as 42.20 Bq kg, 0.11(0.15), 20.67 nGy h, 0.025 mSv y, for all samples respectively. The calculated radiological hazard indices were below the world averages and did not pose any significant health risk to beachgoers.