Determining the natural radioactivity of spices widely used in Iraq

Abstract

The aim of present work is measuring the natural radioactivity of uranium-238, thorium-232 and potassium-40 in some spice samples that widely use in Iraq. Based on these measurements, the corresponding radiological hazardous parameters were evaluated. Ten types of spices retailed throughout Iraq were tested. Gamma spectrometry NaI (Tl) reagent was used for the radiometric assessment. The average activity concentration values of ²²⁶Ra, ²³²Th and ⁴⁰K ranged from 0.43–1.7, 0.16–0.67 and 18.7–220.4 Bq kg⁻¹, respectively. The annual external effective doses due to exposure for each radionuclide (²²⁶Ra, ²³²Th and ⁴⁰K) in these spices were ranged from 14.7 μSv (black pepper) to 110.4 μSv (thyme), 11.9 μSv (black pepper) to 106.3 μSv (cumin) and 16.7 μSv (black pepper) to 181 μSv (majoram), respectively. The annual effective ingestion of ²²⁶Ra varied from 0.48 μSv y⁻¹in cubeb to 0.12 μSv y⁻¹ in black pepper. The dose from the ingestion of ⁴⁰K in all samples can be considered low when compared to UNSCEAR dose level (170 μSv y⁻¹). The results show that, these types of spices do not present any serious hazard and are considered radiologically safe for human consumption.