Natural radioactivity and radiological risk in spices from southeastern Turkey: a pre-earthquake baseline study

Abstract This study aimed to determine the activity concentrations of naturally occurring radionuclides ( 226 Ra, 232 Th, and 40 K) in commonly consumed spices collected from Kilis, southeastern Turkey, before the 2023 Kahramanmaraş earthquakes, and to assess the associated radiological health risks for adult consumers. Eleven spice samples were analyzed using NaI(Tl) gamma-ray spectrometry. Activity concentrations were determined for 226 Ra, 232 Th, and 40 K, and annual committed effective doses (E ing ) were calculated based on an assumed annual spice consumption of 1.8 kg per year. Dose conversion factors recommended by the International Commission on Radiological Protection (ICRP Publication 72) were applied. The mean activity concentrations were 25.70 ± 2.12 Bq·kg −1 for 226 Ra, 24.43 ± 1.65 Bq·kg −1 for 232 Th, and 409.67 ± 24.1 Bq·kg −1 for 40 K. The corresponding average total annual committed effective dose was 27.64 μ Sv·y −1 , well below the global UNSCEAR reference value of 290 μ Sv·y −1 for ingestion of natural radionuclides. Strong positive correlations were observed between 226 Ra, 232 Th, and total dose, indicating their predominant contribution to internal exposure. All measured radionuclide levels in the examined spices were within internationally accepted safety limits, suggesting negligible radiological health risk for typical adult consumers. The findings provide critical pre-seismic baseline data for post-earthquake environmental and food safety assessments in southeastern Turkey.