Radiation hazards and effective dose evaluation: A study of various imported walnut consumed in Kurdistan-Iraq

Twenty commercially available walnut samples that contain naturally occurring radioactive material were used in the investigation. The samples, which include local product codes (LP1-LP11) and imported product codes (IP12-IP20), are offered by major retailers in the Kurdistan Region of Iraq. The radiological risk of consuming walnuts (kernels) is evaluated utilizing high-purity germanium (HPGe) gamma-ray spectrometry. The kernel samples recorded the primordial radionuclide activity concentration at values ranging between (10.5 ± 1.3 - 54.5 ± 7.2), (46.7 ± 3.2 - 112.5 ± 22), and (202.7 ± 28 - 1192 ± 134) Bq for 226 Ra, 232 Th, and 40 K, respectively, with codes IP12, originally from Brazil, and IP13 from the USA both recording the greatest activity among these ranges, where most of the samples exceed the accepted range of values worldwide by UNSCEAR at 33, 45, and 412 Bq for 226 Ra, 232 Th, and 40 K, respectively. With the assumption of a daily intake of kernels at 20 grams and the annual intake of 7.3 kg for adults, the annual effective dose (AED) from consuming kernels was evaluated with an average of 59 ± 10, 366 ± 40, and 30 ± 3 μSv for 226 Ra, 232 Th, and 40 K, respectively, where the highest total annual effective dose was recorded from both kernel samples IP12 and IP13 at 728 ± 119 and 692 ± 50 μSv , respectively. This is significantly higher than the UNSCEAR (2000) recommended limit, which is equivalent to the maximum allowable effective dose limit for members of the public (1 mSv ) suggested by the International Commission on Radiological Protection (ICRP). This suggests that kernel samples examined in this study are unsafe to consume at a dose of 20 grams per day. Additionally, the greatest value of total excess lifetime cancer risk indicated for the sample IP12 from Brazil at 2.238 × which is four times larger than the recommended limit. Based on these findings, recommendations for the amount of walnut consumption must be updated from the standpoint of radiological risk. • Specific radioactivity concentration levels contained in walnuts have been evaluated using HPGe. • The annual effective dose (AED) of consuming walnuts has been evaluated. • Internal dose exposure from consuming walnuts has been assessed. • Recommendations for updated guidelines are made to prevent the raised radiation exposure level.