Mean Activity Concentrations Of 226Ra Research Articles

Radioactive characterization of phosphogypsum from Imbituba, Brazil

This research aims to characterize the content of natural occurring radionuclides in phosphogypsum stacks at Imbituba, Santa Catarina state, Brazil. 226Ra, 228Ra, 40K, 238U and 232Th were determined in PG, soils and sediment samples by gamma spectrometry using the hyper pure germanium detector and neutron activation. The migration of radionuclides in the phosphogypsum profile did not show the same behavior for all sampling sites. The mean activity concentration of 226Ra was 95 Bq kg−1, which is far below the limit recommended by the U.S. Environmental Agency (USEPA) for its application in agriculture (370 Bq kg−1) and the Brazilian Commission of Nuclear Energy Resolution 113 that established a reference level of 1000 Bq kg−1 of 226Ra or 228Ra for the use of PG in agriculture as well as building materials.

Environmental and radio-ecological studies on shallow marine sediments from harbour areas along the Red Sea coast of Egypt for identification of anthropogenic impacts

Analysis of marine sediments of the studied localities provides investigators with data to characterise the composition of these sediments allowing for the identification of particular pollution sources. A study of texture, geochemistry, X-ray diffraction and natural radionuclide content of shallow marine sediments from Quseir harbour, Safaga harbour and El-Esh area in the Red Sea coast of Egypt was conducted for the purpose of assessing the possible influence of human activities on the composition of the sediments. The activity concentrations of the naturally occurring radionuclides 226Ra, 232Th and 40K were measured by using γ-ray spectrometry. The mean activity concentrations of 226Ra, 232Th and 40K in all areas studied were found to be 71±6, 66±5 and 92±7 Bq kg−1 for 226Ra, 83±5, 71±7 and 162±23 Bq kg−1 for 232Th and 513±10, 493±20 and 681±28 Bq kg−1 for 40K, respectively. The results of the study presented were compared with corresponding results obtained in other coastal and aquatic environments in the Red Sea.

Radiological hazard assessment for building materials incorporating phosphogypsum made using Eshidiya mine rock in Jordan

The mean activity concentrations of 226Ra, 232Th, and 40K in Eshidiya phosphogypsum samples were measured as 351.4 ± 23.4, 3.8 ± 0.3, and 120.7 ± 8.3 Bq kg−1, respectively. The results show that the mean values of activity concentration of 226Ra, 232Th, and 40K are in the lower range of typical values reported for phosphogypsum samples collected worldwide. Radiological hazard indices such as the radium-equivalent activity (Raeq), the gamma index (Iγ) alpha index (Iα), the absorbed gamma dose rate (Din), and the corresponding annual effective dose (Ein) were assessed for building materials for dwellings. The results of assessment exhibit that all phosphogypsum samples are higher than the recommended safe limit for building materials for dwellings, except for the radium-equivalent activity (Raeq). Overall assessment, it can be concluded that the possibility of using Eshidiya phosphogypsum in building materials in proportions lower than 100 % will be safe. The mixture of phosphogypsum with normal gypsum can dilute the concentrations of natural radionuclides allowing the use of the mixed building materials to be safe from a radiological point of view.

Radioactivity level in soil of a palaeo beach in the south-eastern part of Bangladesh and evaluation of radiation hazard

A small part of the palaeo beach formation extending along the south-eastern fringe of Bangladesh was selected as study area. The sandy beach formation, enriched with heavy mineral sands containing ²³²Th-bearing monazite, is covered by a thin layer of top soil. Activity concentrations of natural and artificial radionuclides (²³⁸U, ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs), outdoor and indoor annual effective dose rates and the radiation hazard indices were determined in the soil. The radionuclides, investigated by direct gamma-ray spectrometry using HPGe detector, showed that mean activity concentrations of ²²⁶Ra, ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs in soils were 254.53 ± 6.66, 193.95 ± 7.23, 362.18 ± 6.45, 135.79 ± 24.63 and 2.21 ± 0.49 Bq kg⁻¹ respectively. The mean value of radium equivalent activity, external and internal hazards, outdoor absorbed dose rate and total annual effective dose rate were 783.24 Bq Kg⁻¹, 2.12 and 2.80, 354.32 nGyh⁻¹ and 2.52 mSv y⁻¹, respectively, which exceed the average worldwide limit and may pose a radiological threat to inhabitants.

Evaluation of Naturally Occurring Radioactivity Materials (NORM) of Soil and Sediments in Oil and Gas Wells in Western Niger Delta Region of Nigeria

Oil mineral leases (30, 58 and 61) in Delta and River States are the major oil blocks in the oil and gas rich Niger Delta region of Nigeria that is characterized by environmental degradation from oil and gas activities. This research work presents an analytical approach on natural radioactivity assessment in soil and sediment in 15 oil fields of these OMLs. Concentrations of natural radionuclides (226Ra, 232Th and 40K) were determined using gamma spectroscopy. The mean activity concentration of 226Ra, 232Th and 40K for OML30 is 40.2 ± 5.1, 29.9 ± 4.2 and 361.5 ± 20.0 Bq kg−1, respectively; the corresponding values obtained for OML58 is 20.9 ± 2.8, 19.4 ± 2.5 and 260.0 ± 14.1 Bq kg−1, respectively. While the mean activity concentration of 226Ra, 232Th and 40K for OML61 is 29.3 ± 3.5, 21.6 ± 2.6 and 262.1 ± 14.6 Bq kg−1, respectively. These values obtained show enhanced NORMs, but are well within the world range and values reported in some regions and countries of the world, and are slightly above control values, values obtained in Southwestern region of Nigeria and some countries reported average values. The study also examined some radiation hazard indices, the mean values obtained are 86.6 ± 9.3 Bq kg−1, 0.6 Bq kg−1, 40.8 ηGy h−1, 0.05 μSv y−1, 0.2 and 0.3 for radium equivalent activity (Raeq), representative level index (Iγ), absorbed dose rates (D), annual effective dose rates (E ff dose), external hazard index (H ex) and internal hazard index (H in), respectively. These calculated hazard indices to estimate the potential radiological health risk in soil and sediment are well below their permissible limits. The soil and sediments from the study area provide no excessive exposures for the inhabitants and can be used as construction materials without posing any radiological threat or harm to the public users. However, oil-field workers and host community residents are cautioned against excess exposure to avoid future accumulative dose of these radiations from sludge and sediment of this area.

Evaluation of NORM and Dose Assessment in an Aluminium Industry in Nigeria

The activity concentrations of natural radionuclides 226Ra, 232Th and 40K in bauxite ore, alumina, dross tailing, aluminium scraps and soil samples collected from an aluminium industry in Nigeria were determined by gamma ray spectroscopy method. The mean values of 226Ra, 232Th and 40K content of the samples ranged from 16 ± 6 (alumina) to 31 ± 10 (scrap), 41 ± 0.12 (scrap) to 134 ± 21(bauxite) and 47 ± 14 (bauxite) to 354 ± 8 (scrap) Bq·kg-1, respectively. The mean activity concentrations of 226Ra and 40K in all the samples are lower than the world average for soil while 232Th is higher with the exception of alumina and scrap. As a measure of radiation hazard to the occupational workers and the members of the public, the radium equivalent activities and external gamma dose rates due to the radionuclides at 1 m above ground surface were calculated. The radium equivalent activities which varied between 88 ± 10 (alumina) and 222 ± 34 (bauxite) Bq·kg-1 are within the safety recommended limit of 370 Bq·kg-1. The mean annual effective doses calculated from the absorbed dose rates in air were between 54 ± 6 (alumina) and 134 ± 20 (bauxite) μSv·y-1, which is lower than the 1 mSv·y-1 recommended for the general public. The annual gonadal dose equivalent of all the samples with the exception of alumina was higher than the world average for soil.

Natural radionuclide content of disposed phosphogypsum as TENORM produced from phosphorus fertilizer industry in Turkey

This study aims to determine radiological characterization of disposed phosphogypsum (PG) as technologically enhanced naturally occurring radioactive material produced from phosphorus fertilizer plants (PFPs) in Turkey and evaluate radiological impacts of outdoor storage and transport and the usage of PG as additive and filling materials in building sector and road construction. The mean activity concentrations of 226Ra, 232Th and 40K measured for the PG samples from PFP A and PFP B are 125.0, 15.1 and 7.5Bqkg−1 and 436.0, 9.4 and 13.0Bqkg−1, respectively. The mean activity concentrations of 226Ra, 232Th and 40K are also compared with available reported data from other countries in the literature. The mean value of radium equivalent activity (Raeq) index calculated for the PFP A PG samples is 146.7Bqkg−1 which is lower than the limit of 370Bqkg−1 set for building materials and for the PFP B PG samples is 449.6Bqkg−1 which is within the recommended safety limits for usability of PG as aggregate in making roads, streets, pavements and railroad ballast. Generic exposure scenarios given in the Radiation Protection 122 were used for radiological evaluation for members of the public and workers. The mean annual effective doses evaluated for members of the public and workers are lower than the annual limit of 1mSvy−1.

Radon exhalation and natural radiation exposure in low ventilated rooms

In the first part of this paper, the influence of radon (222Rn) exhalation rate from walls and air exchange upon its concentration in room air was considered using a simple mathematical room model. The exhalation rates have been determined in ten low ventilated rooms of ten villas in Jeddah city (Western Province) of Saudi Arabia. An electroprecipitation method has been applied for the determination of the 222Rn gas concentration in these rooms. The mean 222Rn gas concentration was found to be 46.80±8.80Bqm−3. The mean 222Rn exhalation rate was estimated to be 20.11±6.90Bqm−2h−1. The mean inhalation dose due to the exposure to 222Rn gas was calculated to be 1.18±2.30mSvy−1.The second part of this paper deals with a study of natural radionuclide contents of samples collected from the building materials of these rooms under investigations in part one. Analyses were performed in Marinelli beakers with a gamma spectroscopy system to quantify radioactivity concentrations. The collected samples revealed the presence of the uranium–radium (226Ra) and thorium (232Th) radioisotopes as well as 40K. The mean activity concentration of 226Ra, 232Th and 40K was determined to be 48.30±5.08, 43.90±5.63 and 223.90±7.55Bqkg−1, respectively. These activities amount to a radium equivalent (Raeq) of 125.96±15.90Bqkg−1 and to a mean value of external hazard index (Hex) of 0.34±0.04.

Evaluation of potential exposure risks of natural radioactivity levels emitted from building materials used in Adana, Turkey

In this paper, the natural radioactivity levels in a total of 117 samples of 14 different building materials collected from building construction sites and from the retailers in Adana were studied by means of gamma-ray spectrometer with HPGe detector. The mean activity concentrations of 226Ra, 232Th and 40K measured in the studied building material samples ranged from 2.1 to 88.2 Bq kg−1, 1.8 to 52.7 Bq kg−1 and 68.1 to 847.5 Bq kg−1 for 226Ra, 232Th and 40K radionuclide, respectively. The external and internal index, the indoor absorbed dose rate and the corresponding annual effective dose were evaluated for potential exposure risks from the usage of the building material samples. The evaluated values of the external and internal index were below the recommended upper level. All the values of effective annual dose determined were lower than recommended exemption level of 0.3 mSv. The results suggest that the use of the studied building material samples in the construction of buildings is unlikely to give rise to any significant radiation exposure to the residents.

Determination of natural radioactive elements in Abo Zaabal, Egypt by means of gamma spectroscopy

The natural nuclide gamma-ray activities and their respective annual effective dose rates, produced by 238U, 232Th, 40K and 226Ra, are determined for 10 different natural samples (soil–plant–water) from Abo Zaabaal Lake. This lake is located very close to the Egyptian reactors. The gamma spectra analysis indicates that the photo-gamma lines represent ten radioactive nuclides 234Th, 239Pu, 228Ac, 226Ra, 212Pb, 214Pb, 208Tl, 212Bi, 214Bi and 40K. These nuclides represent the daughters of the natural radioactive series 238U and 232Th with 40K. The mean activity concentration of 238U was found to be 6.57, 10.16 and 5.44Bqkg−1 for (soil–plant–water); 8.46, 8.33 and 6.04Bqkg−1 of 232Th, and 136.3, 216.8 and 119.2Bqkg−1 of 40K respectively. The mean activity concentrations of 226Ra were obtained which help to evaluate the radiation hazard indices as radium equivalent, internal and external hazard indices. In addition, to assess the radiation risk to a biosystem, the annual effective dose rate, the absorbed dose in human and the absorbed dose outdoor are also evaluated.

Mineralogical, geochemical and radiological characterisation of Selmo Formation in Batman area, Turkey

This work deals with the mineralogical, geochemical and radiological characterisations of Selmo Formation in Batman neighbourhood. The upper Miocene–Pliocene Selmo Formation is common in the centre of Batman and composed of carbonated sandy claystones and silty–sandy stone lenses. The common whole minerals of the samples are quartz, feldspars, calcite and dolomite. The clay minerals are smectite, illite, chlorite and mixed-layer clay (chlorite–smectite). The geochemical mean values of the samples are 51.7% SiO2; 12.6% Al2O3; 6.2% Fe2O3; 3.6% MgO; 6.3% CaO; 1.1% Na2O; 1.7% K2O; 0.8% TiO2; 0.2% P2O5; 0.1% MnO; and 0.03% Cr2O3. In addition, baseline maps for the concentrations of each radionuclide, the radium equivalent activity and the outdoor gamma dose rate distributions have been plotted for the study area. The mean activity concentrations of 226Ra, 232Th, 40K and 137Cs were determined to be 32, 24, 210 and 9 Bq kg−1, respectively. The assessments of the radiological hazard indices, such as radium equivalent activity, absorbed dose rate in air, annual effective dose equivalent, excess lifetime cancer risk, external hazard index and internal hazard index, were calculated and compared with the internationally accepted reference values. This study shows that the concentrations of radioactivities in the measured samples were within the recommended safety limits and did not pose to be any significant source of radiation hazard.

Spatial distribution of the 226Ra activity concentrations in well and spring waters in Serbia and their relation to geological formations

A survey of radium activity concentrations in well and spring waters in Serbia was conducted and their correlations with geological formations were analysed. Water samples were collected from 170 sampling sites and analysed by gamma-ray spectrometry. The mean activity concentrations of 226Ra were found to be 0.36 Bq L − 1 and 0.57 Bq L − 1 in well and spring waters, respectively. In more than 90% of the analysed waters the 226Ra activity concentrations were below 1 Bq L − 1 . The highest activity concentrations of this radionuclide (up to 17 Bq L − 1 ) were found in crystalline rocks- and carbon dioxide rich-aquifers. The mapping results provide a baseline to identify regions that may require additional assessment of radiation exposure by local communities.

Assessment of natural radiation exposure levels and mass attenuation coefficients of lime and gypsum samples used in Turkey

The activity concentrations of 226Ra, 232Th, and 40K in lime and gypsum samples used as building materials in Turkey were measured using gamma spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 38±16, 20±9, and 156±54 Bq kg(-1) for lime and found to be 17±6, 13±5, and 429±24 Bq kg(-1) for gypsum, respectively. The radiological hazards due to the natural radioactivity in the samples were inferred from calculations of radium equivalent activities (Raeq), indoor absorbed dose rate in the air, the annual effective dose, and gamma and alpha indices. These radiological parameters were evaluated and compared with the internationally recommended limits. The experimental mass attenuation coefficients (μ/ρ) of the samples were determined in the energy range 81-1,332 keV. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It is found that the calculated values and the experimental results are in good agreement.

Determination of natural radioactivity in rock salt and radiation doses due to its ingestion

The Khewera Mines located in Pakistan contain the world’s second largest reserves ofrock salt. Rock salt is used in Pakistan in food recipes. It was decided toinvestigate the concentrations of naturally occurring radionuclides in rock saltfrom the Khewera Mines. Samples of rock salt were collected from 10 differentlocations and analysed by gamma spectrometry. The mean activity concentrations of226Ra,232Th and 40K were 790 ± 262, 640 ± 162 and 23 000 ± 6000 mBq kg−1, respectively. The mean annual effective dose due to the intake ofnatural radionuclides from rock salt for adults was estimated to be0.0638 ± 0.015 mSv, which is lower than the average annual effective dose of 0.29 mSv received percaput worldwide due to the ingestion of natural radionuclides, as reported bythe United Nations Scientific Committee on the Effects of Atomic Radiation in2000.

Radiological Characterization around the Afsin-Elbistan Coal-Fired Power Plant in Turkey

A radiological characterization of soil samples around the Afsin-Elbistan coal-fired thermal power plant in the Mediterranean region of Turkey was carried out. Moreover, activity concentrations and chemical analyses of coal samples used in this power plant and fly ash and slag samples originating from coal combustion were measured. For this purpose, coal, fly ash, slag, and soil samples were collected from this region. The analysis shows that the samples include relevant natural radionuclides such as 226Ra, 232Th and 40K. The mean activity concentrations of 226Ra, 232Th, and 40K were 167, 44, and 404 Bq·kg−1, respectively. Obtained values shows that the average radium equivalent activity, air-absorbed dose rate, annual effective dose, and external hazard index for all samples are 258 Bq·kg−1, 121 nGy·h−1, 148 μSv·y−1, and 0.7, respectively. The environmental effect of natural radionuclides caused by coal-fired power plants was considered to be negligible because the Raeq values of the measured samples are...

Radiological characterization of Cayırhan coal-fired power plant in Turkey

Abstract Natural radioactivity of Cayirhan lignite coal treated at Cayirhan (Ankara, Turkey) power plant, its ash and soil samples mixed with ash in the power plant field were investigated. For comparison, soil samples were collected from a distance of 4 km south of the plant. The analysis shows that the samples include natural radionuclides such as 226Ra, 232Th and 40K. The mean activity concentrations of 226Ra, 232Th and 40K were 57.82, 30.45 and 322.21 Bq · kg−1, respectively. Obtained values shows that the average radium equivalent activity (Raeq), air-absorbed dose rate (D), annual effective dose (AED) and external hazard index (Hex) for all samples are 123.9 Bq · kg−1, 58.90 nGy · h−1, 71.99 μSv · y−1 and 0.34, respectively. The Raeq values of samples are lower than the limit of 370 Bq · kg−1, equivalent to a γ-dose of 1.5 mSv · y−1. The measured activity concentrations for these radionuclides were compared with the reported data of other countries.

Characterization of the TE-NORM waste associated with oil and natural gas production in Abu Rudeis, Egypt

The present study was conducted to characterize the Technically Enhanced Naturally Occurring Radioactive Materials (TE-NORM) waste generated from oil and gas production. The waste was characterized by means of dry screening solid fractionation, X-ray analysis (XRF and XRD) and γ-ray spectrometry. Sediment of the TE-NORM waste was fractionated into ten fractions with particle sizes varying from less than 100 μm to more than 3 mm. The results showed that the TE-NORM waste contains mainly radionuclides of the 238U, 235U and 232Th series. The mean activity concentrations of 226Ra (of U-series), 228Ra (of Th-series) and 40K in the waste samples before fractionation (i.e. 3 mm) were found to amount to 68.9, 24 and 1.3 Bq/g (dry weight), respectively. After dry fractionation, the activity concentrations were widely distributed and enriched in certain fractions. This represented a 1.48 and 1.82-fold enrichment of 226Ra and 228Ra, respectively, in fraction F8 (2.0–2.5 mm) over those in bulk TE-NORM waste samples. The activity ratios of 238U/ 226Ra, 210Pb/ 226Ra, 223Ra/ 226Ra and 228Ra/ 224Ra were calculated and evaluated. Activity of the most hazardous radionuclide 226Ra was found to be higher than the exemption levels established by IAEA [International Atomic Energy Agency, 1994. International Basic Safety Standards for the Protection against Ionizing Radiation and for the Safety of Radiation Sources. GOV/2715/94, Vienna]. The radium equivalent activity (Ra-eq), radon ( 222Rn) emanation coefficient (EC) and absorbed dose rate ( D γr) were estimated and these are further discussed.