Environmental impact assessment of granites bearing rare metals mineralization utilizing airborne gamma-ray spectrometric data, Egypt

This study investigated the radioactivity of granite and its altered varieties using an airborne gamma-ray spectrometer, revealing significantly elevated levels of uranium, thorium, and potassium within specific granitic formations. Higher concentrations were identified in syenogranite, alkali feldspar granite and quartz syenite, while lower levels were observed in metavolcanics, Tonalite-granodiorite and Nubian sandstone. The average activity concentration of ²³⁸U (74 ± 16 Bq kg⁻¹), ²³²Th (80 ± 15 Bq kg⁻¹), and ⁴⁰K (893 ± 122 Bq kg⁻¹) exceeded worldwide averages. The presence of rare metal granites diverges from international standards, due to the presence of minerals harboring radioelements as thorite, monazite, zircon and ferrocolumbite suggests these granites are unsuitable for construction.