Radiation Safety of Medicinal Plants for Consumption from Herbal Shops in Al-Diwaniyah City

Abstract

The increasing reliance on medicinal plants as natural alternatives to pharmaceutical drugs raises important concerns about possible contamination with naturally radioactive materials (NORMs). This study evaluated the specific activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K and their associated radiological health risks in twenty commonly used medicinal plants collected from four herbal shops in Al-Diwaniyah City, Iraq. Gamma-ray spectrometry using a NaI (Tl) detector was employed. The mean concentrations were 3.90 ± 0.39 Bq/kg for ²³⁸U, 13.03 ± 1.16 Bq/kg for ²³²Th, and 548.99 ± 12.65 Bq/kg for ⁴⁰K. While ²³⁸U and ²³²Th activities were below UNSCEAR averages, ⁴⁰K exceeded these limits in 75% of the samples, reflecting both biological uptake and agricultural factors.

All calculated radiological parameters-including radium equivalent activity (Ra_eq), gamma dose rate (DR), internal hazard index (H_in), gamma activity index (Iγ), annual gonadal dose equivalent (AGDE), and annual effective dose for internal exposure (AEDE_in) were within the accepted safety limits. The ingestion effective dose (IED) and the excess lifetime cancer risk (ELCR) also remained below UNSCEAR and ICRP thresholds, confirming minimal radiological risk to consumers.

These findings demonstrate that the examined medicinal plants are radiologically safe under normal consumption patterns. Nevertheless, the elevated ⁴⁰K levels observed in some herbs highlight the need for regular monitoring and regulatory oversight. This study provides essential baseline data for establishing national standards on the radiological safety of medicinal plants in Iraq.