One of the most significant radionuclides in natural drinking waters is 226Ra and its decay products. It is potential of health problems, including cancer risk. In this study, the effect of 226Ra concentration in 28 drinking water samples collected from the North Guilan province was investigated. The activity concentrations of 226Ra were measured by using of radon emanation method and Pylon AB-5 radon scintillation detector. The annual effective dose distribution by age groups, radiological risk and chemical toxicity risk were calculated in drinking water.   The activity concentration results range from a low limit of detection (LLD) 2.0±0.1 mBq l-1 to 38.2±2.4 mBq l-1. Also, the annual effective dose distribution by age groups estimated results were from 1.8×10-6 Sv y-1 for adults to 1.5×10-5 Sv y-1 for infants.  The radiological risk assessment results were 1.06×10-6 to 2.03×10-5 for morbidity risk, 7.32×10-7 to 1.40×10-5 for mortality risk. The chemical toxicity risk results obtained from 1.08×10-1 to 5.63×10-3. The activity concentration level of 226Ra in all drinking water samples were less than the recommended level WHO for drinking water 1000 mBq l-1. Meanwhile, annual effective dose level, cancer morbidity, mortality risk and life annual daily dose due to consumption of selected drink water samples were less than the standard limit.

The presence of primordial radionuclide in human habitats has always been a source of prolonged exposure. Measurement of naturally occurring radionuclides in the environment can be used as baseline to evaluate the impact of non-nuclear activities and also routine releases from nuclear installations. A total of 56 samples from 18 different foodstuff including root vegetables (beetroot, carrot, onion, potato, radish and turnip), leafy vegetables(lettuce, parsley, spinach and white cabbage) and lentil, kidney bean, Soya, eggs, rice, meat, tomato and cooking oil were purchased and analyzed by low level gamma spectrometry. The 226 Ra concentrations from root vegetables varied from 13-62 mBqkg-1 (fw) with turnip of highest concentration, i.e. 62mBq kg-1. Among leafy vegetables; parsley showed the maximum concentration of 228 Ra equal to 173 mBqkg-1 (fw). 226 Ra and 228 Ra contents in the soya, 394 and 578 mBq kg-1 (fw) was much higher than those of other samples respectively. Results indicate that foodstuff consumed by Tehran inhabitants have low radium content and are safe, as far as radium concentrations is concerned.

Naturally occurring radionuclides have different amount of activity concentration for 226 Ra, 232Th and 40K in building materials. In this study, natural radioactivity has been measured for bricks used in Tehran. For this work, 9 samples of three types of bricks, clay brick (CB), making the facade brick (MFB) and firebrick (FB) has been selected from different regions and factories in Tehran. Gamma rays analyzed by high purity germanium (HPGe) detector and spectroscopy system. As the results show, the maximum value of the mean 226 Ra, 232Th and 40K for clay brick has been 17, 9 and 422Bq/kg respectively. Maximum of radium equivalent activities (Raeq) were calculated 62.81Bq/kg that less than the level has been determined 370Bq/kg for building materials. Other type of bricks had low amounts compared to clay bricks. The calculation results show that the bricks are safe for inhabitants because hazard indexes for gamma were below the standard was been introduced. The results of this research compared with other studies in different countries

Nuclear radiations are harmful to the human body. The main sources of nuclear radiation are the decay chains of U-238, U-235, and Th-232 and also some radionuclides as K-40, which are present in small amounts in the materials of the earth's crust, including plants, rocks, soil and water. Radioactive substances are transferred to the human body in a variety of ways, including plant and animal products. Therefore, it is very important to determine the amount of radioactive substances in food products. In this research, seven samples of pistachios with different types were collected from Tehran markets in Iran. In this project, ultra-pure germanium spectroscopy system model GCD30195 was used. The specific activities of Ra-226, Th-232 and K-40 varied from ‎<1.96‎‎ to 9.86, from 1.21 to 1.95, and from 317.22 to 382.80 Bq.kg-1. The artificial radionuclide of Cs-137 in all samples was lower than minimum detectable value (MDA). Calculations of the radiological impact showed that consumption of pistachios would endanger human health. The results of this study also showed that the amount of natural radionuclides in pistachio cores is higher than pistachio shells.

The specific activity of radionuclides in the soil of the Borujerd region using high purity Germanium detector (HPGe) was measured and the associated radiological hazards were calculated. The mean specific activity of radionuclides of Ra-226, Th-232, K-40, and Cs-137 in soil was obtained at 10.99±5.11, 35.36±4.44, 324.20±10.24, and 2.93±0.60 Bq.kg-1. These values were below the global average. Also, the value of basic radiological risk parameters, such as Raeq, AEDout, AEDint, Hex, Hin, and Iγ, ranged from 52.02 to 139.54 in Bq.kg-1, from 24.98 to 68.27 and from 42.90 to 117.22 in mSv.y-1, 122.57 to 334.93, 0.14 to 0.37, 0.16 to 0.40, and 0.27 to 1.04, respectively. The range of excess lifetime cancer risk (ELCR) value for the surrounding soil samples varied from 0.15×10-3 to 0.41×10-3, in which samples S4, S14, S24, S27, S28, S29, and S30 exceeded the global average of 0.29×10-3. A radiological map of the city of Borujerd was prepared using the GIS program. The study showed that the level of radioactivity in the Borujerd area did not exceed the critical value and is in line with the global results.

226 Ra and 228 Ra contents in foodstuffs of Ramsar which is a coastal city in the northern part of Iran were determined by gamma spectrometry. Measurement results together with food consumption rates were used to estimate annual effective dose from 226 Ra and 228 Ra, due to consumption of food stuffs by inhabitants of Ramsar city A total of 33 samples from 11 different foodstuffs including root vegetables (beetroot), leafy vegetables (lettuce, parsley and spinach) and tea, meat, chicken, pea, broad bean, rice, and cheese were purchased from markets of Ramsar city and were analyzed for their 226 Ra and 228Ra concentration. 1-8 kg of fresh weight sample was placed in Marinnelli beaker and sealed. The measurement of natural radioactivity levels as performed by gamma-spectrometry system, using a high purity germanium (HPGe) detector with 40% relative efficiency. The highest concentrations of 226Ra and 228 Ra were determined in tea samples with 1570 and 1140 mBq/kg, respectively, and the lowest concentration of 226Ra was in pea, cheese, chicken, broad bean, and beetroot. The maximum estimated annual effective dose from 226 Ra and 228 Ra due to consumption of foodstuffs were determined to be 19.22 and 0.71 mSv from rice and meat samples respectively, where as, the minimum estimated annual effective dose for 226Ra was 0.017, 0.018 and 0.019 mSv from beetroot, cheese and pea samples respectively.

‎The concentration of naturally occurring radioactive materials (NORM) in surface water and irrigation wells is measured using gamma ray spectrometry by HPGe detector‎. ‎Measurement was carried out for samples that were collected over seventeen points in Tehran city and its suburbs‎. ‎The samples were prepared in compliance with the principles from irrigation wells of city‎. ‎The specific radioactivity of Ra-226‎, ‎Th-232 and K-40 were measured and the results from different locations covered a range with the minimum being below "minimum detectable activity‎" ‎up to maximum of 4.04‎, ‎and 6.85 and 4.7 Bq per liter of water‎, ‎respectively‎. ‎The accumulation of radioactive materials in the samples from southern areas of Tehran was more than that of central areas‎. ‎Also‎, ‎concentration of Ra-226 in all the samples was less than the Derived Release Limit of Canada and Environmental Protection Agency standard threshold‎.

The main objective of this research is measurement and assessment of the Radon-222 and Radium-226 radioactive levels in mineral water and drinking water in the Sareyn city. The guidelines used for Radon-222 and Radium-226 radiation sampling and analysis were ASTM D: 5072-09 and ISO 13165-1: 2013, respectively. The concentration of Radon-222 and radium-226 in mineral water and drinking water samples was measured by Liquid Scintillation Counter (LSC). The results of the measurements show that the Radon-222 radionuclide concentration in mineral water samples is 1.14-6.71 Bq/L and 4.25-9.72 Bq/L for drinking water samples. Furthermore, Radium-226 was determined in mineral water samples in the range of 0.048-0.248 Bq/L and in drinking water samples in the range of 0.044-0.078 Bq/L. Consequently, Radon-222 and Radium-226 radioactivity concentration in all samples of drinking water are below the permissible limit. However, Radon-222 radioactivity concentration is higher than the standard level in a number of springs that few people use as a source of drinking water. Nevertheless, in order to ensure more than the non-contamination of drinking water sources in Sareyn, radionuclides of Radon-222 and Radium-226 can be systematically evaluated and considered by the proposed method.

Among different kinds of oral cavity cancers, the frequency of tongue cancer occurrence is more significant. Brachytherapy is the most common method to cure tongue cancers. Long sources are used in different techniques of tongue brachytherapy. The objective of this study is to asses the dose distribution around long sources, comparing different radioisotopes as brachytherapy sources, measuring the homogeneity of delivered dose to treatment volume and also comparing mandible dose and dose of tongue in the regions near the mandible with and without using shield. The Monte Carlo code MCNP4C was used for simulation. The accuracy of simulation was verified by comparing the results with experimental data. The sources like Ir-192, Cs-137, Ra-226, Au-198, In-111 and Ba-131 were simulated and the position of sources was determined by Paris system. The percentage of mandible dose reduction with use of 2 mm Pb shield for the sources mentioned above were: 35.4%, 20.1%, 86.6%, 32.24%, 75.6%, and 36.8%. The tongue dose near the mandible with use of shied did not change significantly. The dose homogeneity from the most to least was obtained from these sources: Cs-137, Au-198, Ir-192, Ba-131, In-111 and Ra-226.Discussion and Ir-192 and Cs-137 were the best sources for tongue brachytherapy treatment but In-111 and Ra-226 were not suitable choices for tongue brachytherapy. The sources like Au-198 and Ba-131 had rather the same performance as Ir-192

Radium-226 (226Ra) is a product of the 238U radionuclide decay series that significantly incorporated into the human body through water intake. It can also potentially cause a series of health problems including cancers of the digestive system. Radium-226 (226Ra) is a product of the 238U radionuclide decay series that significantly incorporated into the human body through water intake. It can also potentially cause a series of health problems including cancers of the digestive system.
226Ra has been determined in drinking water samples collected from various locations of Guilan province of Iran. The water samples are taken from public water and urban tap water sources. For evolution of gross a and b exposure precipitation method and proportional scintillator system was used. The radon emanation method was used to measure the radium concentration in drinking water.
The measurements showed the gross α and β concentration ranges were between The average concentration of 226Ra was found (7.6 mBq l-1) in drinking water samples and the average annual effective dose, from the digestion of 226Ra in water samples was calculated to be 1.5 µSv y-1. According to UNSCEAR, the annual effective dose value by ingestion is report to be 0.12 mSv y-1.