Investigation of the radioactivity of sands collected from Bulgarian Black Sea coast

Radionuclide concentrations in coastal sand samples from the Bulgarian Black Sea coast were analyzed using gamma-spectrometry. The average activity concentrations for 238 U, 232 Th, and 40 K were found to be 11.62, 6.82 and 396.55 Bq/kg, respectively, all of which are lower than global averages. Additionally, the technogenic radionuclide 137 Cs was detected in 11 samples, with an average concentration of 3.16 Bq/kg. Radiation hazard coefficients were calculated, and their average values were also lower than the global benchmarks. To explore the relationships between radionuclides and radiological variables, multivariate statistical methods such as Pearson correlation, principal component analysis, and cluster analysis were used. These findings contribute to a more comprehensive understanding of the radiological condition of the environment along Bulgarian beaches.