Abstract
Radiometric monitoring is important for assessing indoor exposure due to ionizing radiation from meal dishes, where standards and guidelines are crucial. For this purpose, in the present study, a gamma-ray spectroscopy NaI (Tl) detector was used to measure the activity concentration levels of 226Ra, 232Th, and 40K in 65 selected samples of meal dishes available in Kurdistan Region which made of clay, porcelain, and ceramic; also, the RAD-7 technique has been used to estimate the in-situ radon concentration (²²²Rn) inside homes and from each sample. The average activity concentration levels of 226Ra in the examined samples were 65.86 ± 7.08 Bq.kg⁻¹ (mean ± SD), ranging from 36.48 Bq.kg⁻¹ (SCL-5) to 106.92 Bq.kg⁻¹ (SCL-11), the average activity concentrations of 232Th were 41.40±7.81 Bq.kg⁻¹ (mean ±SD), with a range from 13.4 Bq.kg⁻¹ (SCE-8) to 82.65 Bq.kg⁻¹ (SCE-42), and the average activity concentrations of 40K were 700.84 ± 84.59 Bq.kg⁻1 (mean ± SD), with a range from 274.66 Bq.kg⁻¹ (SCE-6) to 1572.56 Bq.kg⁻¹ (SP-2). The average concentrations of 226Ra, 232Th, and 40K exceed the mean values documented by UNSCEAR 2000 which are (35,30,420) Bq/Kg.
The evaluated radiological hazard indices of radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), representative alpha index (Iα), gamma index (Iγ), and effective dose rate to different body organs (Dorgan) are well within the global safety limits established by UNSCEAR, while the absorbed dose rate (DR), indoor annual effective dose rate (AED Indoor), and excess lifetime cancer risk (ELCRindoor) are above safety limits. This study employed statistical methods including normality tests, skewness, kurtosis, and matrix correlation coefficients to clarify the statistical properties of measured radionuclide-specific activities and the associated radiological risk criteria.
The radon concentration, surface exhalation rate, mass exhalation rate, and effective radon content, as well as the annual effective dose and excess lifetime cancer risk, were measured using a RAD-7 detector. The results demonstrate that the range of radon concentration, surface and mass exhalation rates, effective radon content, annual effective dose, and excess lifetime cancer risk in the studied samples are (14.2-80.1) Bq.m-3, (0.027-0.151) Bq.m-2. h-1, (0.86-3.83) mBq.kg-1. h-1, (0.114-0.508) Bq.kg-1, (0.356-2.021) mSv.y-1, and (1.25-7.07) ×10-3,respectively. Radon concentrations in all samples fell below the ICRP’s recommended activity range of (100-300) Bq.m-3. The results indicated that the rate of radon release was less than the global average of 57.600 Bq.m-2. h-1. Additionally, the annual effective dose for a number of samples (15 out of 65, or 23%) exceeded the global average value of 1.2 mSv.y-1. The study reveals a strong correlation between radon activity concentration, surface exhalation rate, and mass exhalation rate, suggesting that certain ceramic plate dishes in kitchens increase radon emission levels.
The indoor radon concentration levels in 15 randomly chosen residences in the Erbil city, concentrating on kitchens and guest rooms, were measured. Measurements were conducted using the RAD-7 detector, and revealed that kitchens typically demonstrated elevated radon levels compared to guest rooms, which possibly attributable to inadequate ventilation and the presence of radon-emitting items, including ceramic tiles and conventional cookware. In residences H2, H8, and H15, kitchen radon concentrations are (82,120,79.82) close to 100 Bq.m-3, with H8 equal to 120 Bq.m-3. The annual effective dosage (AED) values show increased exposure levels in kitchens, frequently above the ICRP-recommended threshold of 1.2 mSv.y-1.
In H8, the AED surpassed 3.0 mSv.y-1, indicating a possible long-term health hazard. Lung dosage rate (Dlung) values exhibited comparable tendencies, with kitchens demonstrating markedly elevated levels compared to guest rooms. This rise is ascribed to high radon emissions resulting from cooking plate samples and the materials employed in kitchen construction. The present results underscore the pressing necessity for improved ventilation, implementation of low-emission materials, and heightened public awareness to reduce indoor radon exposure in Erbil residences.
The study recommends stricter regulations for the dish industry, particularly in Kurdistan, regarding the purchase and sale of both local and imported domestic cooking utensils due to radioactivity.
