Effect of natural radioactivity along the southern coastal area of Tamil Nadu with statistical approach

Natural radioactivity was assessed in sediment samples collected along southern coastline of Tamil Nadu. Average activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were determined (29 ± 3, 218 ± 6, and 80 ± 5 Bq kg^–1, respectively). Calculated parameters included radium equivalent activity (347 ± 12 Bq kg^–1), absorbed dose rate (273 ± 10 nGy h^–1), annual effective dose rate (0.33 ± 0.01 mSv y^–1), external hazard index (0.94 ± 0.03), annual gonadal dose equivalent (1026 ± 35 mSv y^–1), and excess lifetime cancer risk (1.17 ± 0.03). Multivariate statistical analyses were employed to examine correlations among the radioactive variables. The presence of heavy minerals in the samples was confirmed using X-ray diffraction.