Mineralogical role on natural radioactivity content in the intertidal sands of Tamilnadu coast (HBRAs region), India

Activity concentration and mineralogical characterization in the intertidal sand samples of Tamilnadu coast, India have been analyzed. From the gamma spectral analysis, the average value of ²³⁸U, ²³²Th and ⁴⁰K in the intertidal sand samples are 12 ± 4, 59 ± 4 and 197 ± 26 Bq kg⁻¹ respectively. The average value of ²³²Th alone is slightly higher than the world average value. From XRD and FTIR analysis, monazite, zircon, ilmenite, magnetite, hematite, quartz, witherite, calcite, nacrite, microcline feldspar, orthoclase feldspar, gibbsite and organic carbon are identified. Of these minerals, monazite and microcline feldspar are the most associated with the presence of ²³²Th and ⁴⁰K respectively.