Activity Concentrations Of Ra-226 Research Articles

Relationship between Ra-226 activity concentration in building materials and indoor radon concentration: An example of Russian high-rise residential buildings

The worldwide trend toward the construction of high-rise buildings with high energy efficiency highlights the role of building materials as a source of indoor radon in the modern urban environment. The aim of the study is to analyze the relationship between the Ra-226 activity concentration in building materials and indoor radon concentration using the example of multi-story buildings in Ekaterinburg. Measurements of the activity concentration of natural radionuclides in building materials were carried out using a new non-destructive method. A radon survey conducted early provided the data on indoor radon concentrations in the same apartments. The obtained Ra-226 activity concentrations in building materials in high-rise buildings were found to be relatively low, ranging from 9.1 to 51 Bq/kg. The typical radon entry rate by diffusion from building materials for modern Russian multi-story buildings can be accepted as equal to 0.5 Bq/(m3∙h) per 1 Bq/kg of Ra-226 activity concentration. Ra-226 in building materials has been shown to be a primary source of indoor radon in modern high-rise buildings, where this factor can cause indoor radon concentrations above the reference level of 100 Bq/m3 at low air exchange rates. The activity concentration of Ra-226 in building materials should be considered a separate parameter for regulation within the national radiation protection systems.

Assessment of annual effective dose from radionuclides in paint materials using High Purity Germanium detector

ABSTRACT The main focus of this study is to investigate the radioactivity concentration, and the hazardous effects of using paint materials for decorative purposes which are available on the market. The gamma radiation from these collected paint samples is detected by using the High-Purity Germanium (HPGe) detector. A total of 20 samples from four brands and five different colours of each brand were collected for this experiment. From this study, the activity concentrations of Ra-226, Th-232 and K-40 in paint samples were found to be varied from 2.20 ± 0.98 to 60.22 ± 7.37 Bq kg−1 with an average value of 20.88 ± 4.05 Bq kg−1, 8.01 ± 3.54 to 87.07 ± 7.68 Bq kg−1 with an average value 28.19 ± 7.70 Bq kg−1 and 21.98 ± 19.39 to 517.92 ± 47.08 Bq kg−1 with an average value 221.70 ± 32.06 Bq kg−1, respectively. The total annual effective dose rate ranges from 0.04 to 0.25 mSvy−1 with an average of 0.15 mSvy−1.

Analytical Study of Fuel Switching from Heavy Fuel Oil to Natural Gas in clay brick factories at Arab Abu Saed, Greater Cairo

Arab Abu Saed area in Giza governorate, south to Cairo contains more than 228 clay brick kilns represent the largest cluster of brickworks in Egypt. Burning of Heavy Fuel Oil (HFO) in such kilns is the main source of air pollution in the surrounding locations. In this study, investigation of switching the fuel used in brick kilns from (HFO) to Natural Gas (NG) is carried out and the pollution loads are assessed in both cases. In addition, two Gaussian dispersion plume models are employed to estimate the concentration of primary pollutants; PM10, SO2, and NO2 at seven locations in the vicinity of Arab Abu Saed to determine the most adversely affected locations. Statistical analysis is applied to evaluate the correlation and conformity of the results of both models. Results show that using of NG leads to a significant reduction of pollution loads of PM10, SO2 and NO2 reaches 96%, 72%, and 24% respectively. In addition, the reduction of naturally occurring radionuclides in air is analyzed. Activity concentrations of Ra-226, Th-232 and K-40 in Bq/l for HFO were measured using HPGe detector for six HFO samples. Exposure due to air submersion of naturally occurring radionuclides in the study area leads to annual equivalent dose ranged between 2.16 mSv/y (received by Uterus) and 14 mSv/y (received by skin), and average effective dose 2.65 mSv/y which represent valuable exposure.

Determination of Radium-226 in Rock Samples by Liquid Scintillation Counter

The present work examines the validity of using barium as a carrier for radium-226 determination and optimizes the amount added during the radiochemical separation from rock samples. The activity concentration of Ra-226 is determined in rock samples by liquid scintillation spectrometer via its short-lived daughters after the radiochemical separation. The activity of Ra-226 was calculated based on the counts measured in a window set for Po-214 peak. The activity measured by Liquid Scintillation Counter, LSC using Pulse Shape Analysis, PSA. Ba-133 was used for chemical yield. The applied method was tested using a Certified Reference Material, CRM ore number-Dl-1a which shows a good agreement with the certified values. The applied method for measuring Ra-226 has been adapted to be used in rocks such as monazite. The average activity for Ra-226 in rock samples collected from the commercial grade Egyptian monazite was 13.85 ± 2.05 Bq/g with a detection limit 9.58 mBq/g. The optimum conditions have been established during the present work such as precision, cost and time preparation which makes the method useful for radio chemists and the decision makers.

Radium content and radon exhalation rate from sulfur polymer composites (SPC) based on mineral fillers

Several samples of materials of potential interest as component in building materials, especially in sulfur polymer concrete (SPC) composites, were checked for their radium content and radon exhalation rate. However, the radiation hazard strongly depends on radon exhalation rate from these materials, the influence of SPC composition was investigated concerning radon exhalation and emanation from the composite matrix. The accumulation method using RAD7 device was used for specific exhalation rate determinations. The activity concentrations of Ra-226 in the man-made tiles were in the range of 6.1–593 Bq·kg−1. The Rn-222 exhalation rates from these materials were in the range of 103 mBq·m−2 h−1–9.22 Bq·m−2 h−1, whereas from the SPC composites from 40.2 to 438 mBq·m−2 h−1. SPC manufacture technology and sulfur polymers applied for composites preparation allow for nearly 50-fold decrease of radon emanation coefficient. Different factors (e.g.: physical form of additives or polymer composition and its weight fraction) affecting radon emanation coefficient and its exhalation rate from examined raw materials and composites were discussed. Using a standard room parameters, the Rn-222 concentration resulting from its exhalation from the walls and annual internal doses were estimated indicating for satisfactory results even for raw materials of the highest Ra-226 concentration.

Leachability of radium-226 from industrial phosphogypsum waste using some simulated natural environmental solutions

This study investigated the leaching of radium-226 from phosphogypsum (PG) waste produced from the fertilizer industry by synthetic solutions that replicate water that may contact the waste in natural conditions. The results indicated that the activity concentration of Ra-226 in the PG was 461 ± 12 Bq kg−1 and compared with other studies carried out worldwide. The leached percentage of Ra-226 represents the exchangeable fraction loosely bounded in the matrix of the PG waste. The leached fraction of Ra-226 was 6.5 ± 0.6 and 9.0 ± 0.5% when the waste was exposed to rainwater and saline solution, respectively. It is also found that the leaching fraction increased 10–12 ± 0.4% when the waste was exposed to the admixture of saline solution containing Sr2+ or Ba2+ cations, whereas it was lowered to 4–5 ± 0.5% in the presence of carbonate or sulfate anions. When the PG is used as an economic fertilizer, the irrigation water can leach 7.8 ± 0.6% of Ra-226 that could contribute to plant uptake, thereby to animal and/or human consumption. The primary tests of the drinking water (well and tap resources) consumed by the populations surround the PG facility showed that the activity concentration of Ra-226 was below the minimum detectable activity.

NORM in soil and sludge samples in Dukhan oil Field, Qatar state

Abstract: The main objective of this work is to measure the activity concentrations of Naturally Occurring radioactive Materials (NORM) produced as a buy products in oil production. The analyses of NORM give available information for guidelines concerning radiation protection. Recently NORM subjected to restricted regulation issued by high legal authority at Qatar state. Twenty five samples of soil from Dukhan onshore oil field and 10 sludge samples collected from 2 offshore fields at Qatar state. High resolution low-level gamma-ray spectrometry used to measure gamma emitters of NORM . The activity concentrations of natural radionuclide in 22 samples from Dukhan oil field, were with average worldwide values . Only three soil samples have high activity concentration of Ra-226 which is more than 185 Bq/kg the exempted level for NORM in the Quatrain regulation. The natural radionuclide activity concentrations of 10 sludge samples from offshore oil fields was greater than 1100Bq/kg the exempted values of NORM set by Quatrain regulation so the sludge need special treatments. The average hazards indices (H ex , D , and Ra eq ), for the 22 samples were below the word permissible values .This means that the human exposure to such material not impose any radiation risk. The average hazards indices (H ex , D , and Ra eq ),for 3 soil samples and sludge samples are higer than the published maximal permissible. Thus human exposure to such material impose radiation risk.

Assessment of natural and artificial radioactivity levels and radiation hazards and their relation to heavy metals in the industrial area of Port Said city, Egypt

A detailed gamma ray spectrometry survey was carried out to make an action in environmental impact assessment of urbanization and industrialization on Port Said city, Egypt. The concentrations of the measured radioelements U-238, Th-232 in ppm, and K-40 %, in addition to the total counts of three selected randomly dumping sites (A, B, and C) were mapped. The concentration maps represent a base line for the radioactivity in the study area in order to detect any future radioactive contamination. These concentrations are ranging between 0.2 and 21 ppm for U-238 and 0.01 to 13.4 ppm for Th-232 as well as 0.15 to 3.8 % for K-40, whereas the total count values range from 8.7 to 123.6 uR. Moreover, the dose rate was mapped using the same spectrometer and survey parameters in order to assess the radiological effect of these radioelements. The dose rate values range from 0.12 to 1.61 mSv/year. Eighteen soil samples were collected from the sites with high radioelement concentrations and dose rates to determine the activity concentrations of Ra-226, Th-232, and K-40 using HPGe spectrometer. The activity concentrations of Ra-226, Th-232, and K-40 in the measured samples range from 18.03 to 398.66 Bq kg(-1), 5.28 to 75.7 Bq kg(-1), and 3,237.88 to 583.12 Bq kg(-1), respectively. In addition to analyze heavy metal for two high reading samples (a 1 and a 10) which give concentrations of Cd and Zn elements (a 1 40 ppm and a 10 42 ppm) and (a 1 0.90 ppm and a 10 0.97 ppm), respectively, that are in the range of phosphate fertilizer products that suggested a dumped man-made waste in site A. All indicate that the measured values for the soil samples in the two sites of three falls within the world ranges of soil in areas with normal levels of radioactivity, while site A shows a potential radiological risk for human beings, and it is important to carry out dose assessment program with a specifically detailed monitoring program periodically.

Natural radionuclides in mineral water in Germany

Abstract The activity concentrations of Ra-226, Ra-228, Po-210, Pb-210, U-234, U-235, U-238 and Ac-227 have been determined in approx. 400 bottled mineral waters in Germany. The median value of radiation exposure for children (age 0–1 year, 1701/y) is 0.047 mSv/a. The main part of exposure (80–90% approx.) is caused by the isotopes Ra-226 and Ra-228. The median values of concentrations are 7 mBq/l, respectively. Maximal concentrations up to 370 mBq/l were observed.

Uptake and long term behavior of naturally occurring radionuclides in tree rings of spruce

The uptake and the radial distribution of naturally occurring radionuclides in the tree rings of a spruce tree were examined. The activity concentrations of Pb-210 are at a constant level of about 1,7 Bq/kg dry weight (dw) in older tree rings but decrease to younger ones. We suggest that Rn-222 dissolved in the soil water is taken up in significant amounts by the tree roots and decays to Pb-210 within the wood. The activity concentrations of Ra-226 of about 2,0 Bq/kg (dw) are nearly constant over all tree rings. Ra-228 however showed a significantly different behavior. Futhermore the activity concentrations of U-, Th- and Pu-isotopes were determined. A depth profile of the soil within the root zone of the spruce gives further informations.