Advanced Physical Research

In response to the documented rise in cancer cases in Al-Diwaniyah City, this study assesses the specific activities of uranium-238 (²³⁸U), thorium-232 (²³²Th), and potassium-40 (⁴⁰K) in commonly used decorative building materials, and evaluates their associated radiological hazards. Twelve imported materials were selected based on popularity and indoor usage, where prolonged human exposure is likely. Gamma spectrometry with a 3"×3" NaI(Tl) detector was employed for activity measurements. The activity measurements ranged from 4.20 ± 0.49 to 34.81 ± 1.45 Bq/kg for ²³⁸U, 3.09 ± 0.92 to 73.33 ± 1.33 Bq/kg for ²³²Th, and 196.09 ± 0.09 to 1787.79 ± 3.66 Bq/kg for ⁴⁰K, with ⁴⁰K showing the highest levels. Calculated hazard indices included radium equivalent activity Ra_eq (37.89–243.52 Bq/kg), absorbed dose rate DR (18.36–119.63 nGy/h), annual effective dose equivalent AEDE (0.01–0.58 mSv/y), and activity utilization index AUI (0.18–1.06). While most indices were within safety limits, excess lifetime cancer risk ELCR values (0.31× 10⁻³–2.03 × 10⁻³) exceeded international thresholds in some samples. A significant correlation was observed between ²³²Th and ⁴⁰K. Although average values complied with UNSCEAR recommendations, certain samples presented potential health risks, underscoring the need for stricter monitoring and regulatory control of imported decorative materials used indoors.