A national survey of natural radionuclides in soils and terrestrial radiation exposure in Iran.

Natural radiation is a feature of the environment in which we live. One of the contributions of human exposure to ionizing radiation due to natural sources arises from gamma radiation. Therefore, present study was aimed to evaluate and map indoor gamma dose rate in Tehran. The corresponding annual effective dose (AED) and excess lifetime cancer risk (ELCR) were also calculated. All measurements were performed by a Geiger Muller detector in 43 dwellings in Tehran. The average indoor gamma dose rate in Tehran was appointed as 343.2 nGy/h. AED and ELCR were calculated as 2.4 mSv and 10.3 × 10-3, respectively. The evaluated indoor gamma dose rate and calculated AEDs and lifetime cancer risk were found higher than the world average value.

Assessment of indoor gamma radiation and determination of excess lifetime cancer risk in tehran in winter and spring 2017.

Background: The health implication of exposure to gamma radiation in the outdoor and indoor environments has become a major concern worldwide. Methods: This study was conducted in the city of Birjand where three stations and buildings were randomly selected to measure the background radiation in outdoor and indoor places; for this purpose, GM detector (X5C plus) was used. All dose rates on the display of the survey meter were recorded, and the mean of all data in each station and buildings was computed and taken as the measured dose rate of that particular station. Results: The average dose rate of background radiation was 71.8 nSv/h for outdoor and 82.0 nSv/h for indoor environments, and the maximum and minimum dose rates were 79.6 nSv/h and 61.7 nSv/h for outdoor measurements and 112.9 nSv/h and 70.8 nSv/h for indoor measurements, respectively. Conclusions: The results revealed that the annual effective dose is 0.49 mSv, which is similar to that of the global level (0.48 mSv). The estimated excess lifetime cancer risk was 1.715 × 10-3, which was high compared to the world average value of 0.25 × 10-3.

Assessment of Outdoor and Indoor Background Gamma Radiation, the Annual Effective Dose and Excess Lifetime Cancer Risk in Birjand, Iran

Background radiation can be different in both indoor and outdoor places. Background radiation is always in the environment, and all people in the community are constantly exposed to it. The most important source of exposure to gamma ray is natural radionuclides. Gamma rays can have harmful effects on the human body. The purpose of this study was to evaluate the health risk of gamma-ray exposure and to simulate using the Monte Carlo simulation. In this study, gamma-ray data were extracted from the studies carried out at intervals January 1, 2000, to December 31, 2018. Iranian and international databases were used to search for the articles. A total of 11 studies were found. To determine the health effects of gamma-ray radiation, the annual effective dose and excess lifetime cancer risk were calculated. To determine the uncertainty, a health risk assessment was conducted via Monte Carlo simulation. In outdoor, the mean, highest, and lowest absorbed dose of gamma ray were 117.82 nSv/h, 295.17 nSv/h, and 49 nSv/h, respectively. Ardabil Province and Chaharmahal and Bakhtiari Province have the highest and lowest gamma ray concentrations, respectively. In indoor, the mean, highest, and lowest absorbed dose of gamma ray were 118.22 nSv/h, 141 nSv/h, and 60.2 nSv/h, respectively. The last column, the mean, maximum, and minimum of excess lifetime cancer risk values for gamma-ray radiation were 2.45E−3, 4.17E−3, and 4.61E−4, respectively.

Estimate the effective dose of gamma radiation in Iran cities: lifetime cancer risk by Monte Carlo simulation model

The study presents a radiometric survey of Background Ionizing Radiation (BIR) dose levels in ten quarry sites located in Ebonyi State, Nigeria. In-situ BIR dose rate measurements, by means of nuclear radiation survey meter, at 1 m above ground level were carried out at the excavation section (ES) and quarrying section (QS) of the investigated quarry sites. The obtained results indicated dose rates ranging from from 0.14 to 0.18 μSv/h with mean of 0.15±0.01 μSv/h at the ES and 0.16 to 0.19 μSv/h with mean value of 0.18±0.01 μSv/h at the QS. While the values obtained at the QS are respectively higher than those measured at the ES, they are all higher than the worldwide average value of 84 nSv/h signifying BIR elevated environments. The estimated mean annual effective dose (AED) and excess lifetime cancer risk (ELCR) are 0.27±0.03 mSv/y and 0.94×10–3 respectively at the ES and 0.31±0.02 mSv/y and 1.07×10–3 at the QS. The obtained AED values for all the sites are well above the outdoor worldwide average value of 0.07 mSv/y but lower than the International Commission on Radiological Protection recommended permissible limits of 1.0 mSv/y for the general public. Generally, the BIR levels of the quarry sites are within acceptable limits and no immediate radiological health threat may be derived from the current levels. However, long-term health effects due to continuous exposure to low-level radiation doses may manifested in future over a lifetime exposure of 70 years as indicated by the ELCR values.
Keywords: Background ionizing radiation, Dose rate, Annual effective dose, Quarry site, Ebonyi State

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Assessment of background ionizing radiation dose levels in quarry sites located in Ebonyi State, Nigeria

Introduction Guilan is one of the provinces in North of Iran, with population of 2,480,874 and a total area of ​​14,042 square kilometers. This study assesses the outdoor natural gamma dose rates in the air of 49 cities in Guilan and calculates corresponding average annual effective dose. Materials and Methods A total of 260 different sample points measurements were carried out. The results include both terrestrial and cosmic ray components of gamma radiation level. Results The outdoor gamma dose rates range from 65 to 127 nSv h-1 with the mean of 94 ± 24 nSv h-1. Conclusion The average outdoor gamma dose rate for Guilan determined in this study is significantly higher in comparison with values reported by UNSCEAR 2000 from different countries with the mean of 59 nSv although in comparison with many provinces of Iran, it is lower.

http://ijmp.mums.ac.ir/article_2622_5b22e391e35a6b7a9b8be1b3eb03af5f.pdf

Saeideh Aghayari

Papers

Assessment of Outdoor Gamma Radiation Dose Rates in 49 Cities of Guilan Province, IRAN