Natural Radionuclides Research Articles

Radioactivity levels, soil-to-grass and grass-to-milk transfer factor of natural radionuclides from grazing area in Erbil governorate, Iraq

The levels of naturally occurring radionuclides in soil, grass, and milk were measured in this study in order to calculate the transfer factor of radionuclides from soil to grass and grass to milk obtained from Erbil governorate in Iraq. High efficiency gamma spectrometry used for the measurement. It has been determined that the mean activity concentrations of 232Th, 226Ra, and 40K are 3.08, 8.37, and 253 BqKg−1 in soil, 0.5, 0.39, and 203.05 BqKg−1, in grass, and 0.29, 0.084, and 29.69 BqL−1, in milk, respectively. For soil to grass, the transfer factor values for 232Th, 226Ra, and 40K were found to be 0.18, 0.052, and 0.84, respectively, for soil to grass. For grass to milk, the transfer factor values for 232Th, 226Ra, and 40K were found to be 0.45, 0.166, and 0.11 dayL−1, respectively. The average transfer factor for 232Th, 226Ra, and 40K in all samples were lower than the world average value.

Evaluation of radiological health risk due to ingestion and inhalation of radon in commercial packaged fruit juices consumed in Turkey

ABSTRACT Fruit juices (FJs) are among the most popular beverages frequently preferred by consumers, believing FJs contain the nutritional values, minerals, phytochemicals, vitamins, and antioxidants necessary for a healthy life. However, FJs may contain natural radionuclides such as radon (222Rn), which originates from the fruit and water utilized in their production, at levels that may pose a health risk to people. Inhalation and ingestion of 222Rn gas increases the risk of lung and stomach cancer. In this study, commercially packaged FJs from the seventeen most popular brands consumed in Turkey were analyzed for physicochemical properties and 222Rn activity concentrations to evaluate the radiological health risk. The values of pH, brix and 222Rn activity concentrations in FJ samples varied from 2.68 to 4.28, 2.50 to 14.30%, 9.6 ± 1.1 to 25.2 ± 2.5 mBq/L, respectively. The radiological health risk caused by internal exposure was evaluated for children and adults by estimating the ingestion and inhalation annual effective dose. The average values of the total annual effective dose for children and adults were found as 0.039 µSv and 0.056 µSv, respectively, which are much lower than the recommended dose of 100 µSv for drinking water.

Estimation of natural radioactivity in the soil samples around the uranium site, royal village, Khandela, Sikar district, Rajasthan.

The measurements of activity concentration of radium ( 226Ra ), thorium ( 232Th) and potassium ( 40K ) natural radionuclides using high purity germanium ( HPGe ) detector to assess harmful effects on people residing around Royal Uranium Site, Sikar, Rajasthan, India. The activity concentrations range from 29.03±3.72 to 69.95±4.07Bq/kg for 226Ra with a mean value of 47.01Bq/kg, 57.99±6.13 to 113.94±6.54Bq/kg with a mean value of 86.56Bq/kg for 232Th,678.19±76.36 to 1426.55±81.32Bq/kg for 40K with a mean value of 1195Bq/kg. Average Radium Equivalent Activity was measured 261.59±35.48Bq/kg. The total outdoor absorbed gamma dose rate ranged from 78.42 to 157.91 nGy/h with a mean value of 122.12 nGy/h.The average annual effective dose equivalent outdoors and indoors was found 0.75mSv.Mean external (Hex) and internal (Hin) hazard indices are measured 0.70 and 0.82, respectively, for the study area.

Estimation of radioactivity in soil and drinking water samples from Northern Gulbarga District of Karnataka.

The gamma activity of the radionuclides238U, 232Th and 40K were measured in surface soil samples collected from 40 villages of Aland, Afzalpur, Ganaghapur and Kamalapur talukas of Northern Gulbarga district, Karnataka. The gamma activity of natural radionuclides were measured using 4" × 4" NaI (Tl) scintillation detector, the spectrum was analysed using a PC based 1k MCA (winTMCA 32 scinti SPEC) and the 222Rn activity concentrations in drinking water were determined by the Emanometry method. The activity of 238U, 232Th and 40K was found to be in the range from 14.3±0.3 to 64.5±6.1, 15.4±0.2 to 95.0±4.1 and 21±06 to 323±09 Bqkg-1, respectively. Outdoor AED from 0.023 to 0.07 mSvy-1 and all the radiological hazards indices were well within the safe limit. The 222Rn activity in ground water is found to vary from 1.11 to 66.6 Bql-1. The total annual effective doses due to 222Rn inhalation and ingestion range from 3.02 to 181.81μSvy-1, respectively, with an average value of 77.18μSvy-1.

Negative effects of population exposure to radon from water

The presence of radionuclides in drinking water, as well as in water used for other purposes, plays a significant role in the exposure of the population. Water monitoring is carried out in order to measure the content of natural radionuclides, primarily radon – 222Rn, and its short-lived descendants. Radon is the only gaseous radioactive product of the uranium series and a direct descendant of radium. The half-life of radon is 3.82 days, and its decay is followed by four descendants: 218Po, 214Pb, 214Bi and 214Po. The solubility of radium in water and its long-distance transport allow radon to accumulate in it, especially if it dissolves uranium-rich rocks. The resulting radon can be introduced into the water by the effect of entrainment and can be transported by underground flowing water to greater distances and entered into the body by ingestion. Radon is moderately soluble in water; it easily leaves it and thus increases its concentration in the air in closed rooms, and is taken into the body by inhalation. Epidemiological studies have shown that radon in drinking water is a secondary source of indoor radiation. The risk of manifesting carcinogenic effects due to exposure to radon, which is introduced into the body in different ways, is represented by chronic daily intake (CDI) of radon. The risk is quantitatively assessed for each entry route, and the simple sum of all entries determines the total exposure risk.

Assessment of Radon and Naturally Occurring Radionuclides in the Vredefort Meteorite Crater in South Africa

The concentric impact rings of the Vredefort Crater contain rocks with elevated uranium concentrations resulting from the geological signature of a meteoric impact. The decay of this uranium was estimated to lead to elevated indoor radon concentrations in the Crater, but such a study has never been carried out. This study explores the relationship between the natural radionuclides found in the geology of the Vredefort Crater and indoor radon concentrations. This was achieved through soil sampling and radionuclide surveys conducted on three impact rings, supplemented by indoor radon measurements in dwellings found in the area. In situ measurements revealed that one impact ring had higher-than-average uranium concentrations at 50 Bq/kg. Surprisingly, the measured indoor radon levels were lower than expected (113 Bq/m3). These measurements were taken during the COVID-19 pandemic and colder months, conditions that would typically result in elevated indoor radon levels. Soil samples indicated uranium activity of 30 Bq/kg, comparable to the world average of 35 Bq/kg. However, defunct mine tunnels in the area exhibited elevated radon concentrations, averaging 364 Bq/m3. The disparity between expected and measured indoor radon levels was attributed to the composition of surficial deposits, bedrock, and architectural features of the dwellings preventing radon accumulation.

Analytical Studies on the Radionuclide Levels of Sediment and Water in an Agricultural Environment in the Egyptian Delta

This paper is an environmental investigation of the concentration values of radioisotopes and hazardous elements, aimed to shed light on industrial pollution and the effect of using fertilizers in the period of irrigation water drainage from cultivated lands, especially in the River Nile, irrigated, and draining channels in the middle portion of the Egyptian river delta. Different samples were analyzed, both for water and sediment. Many physical and chemical characteristics of samples were investigated. Among them are the quantitative measure of the acidity or basicity of aqueous or other liquid solutions (pH), grain size, and the total organic matter content (TOM) have been determined for sediments. pH and TDS, beside other types of pollutants, were determined for water samples. The water and sediment samples pH are slightly alkaline. The mean value of TDS for water samples is 488 mg/l, while he usual TDS value in river is 500 mg/l. The TOM values show that the sediment samples are poor in organic matter content. The bicarbonate range in the water samples is smaller than the same range in river water. The levels of Ra-226, Th-232, and K-40 activity in sediments are highly correlated. Natural radionuclides seem to correlate with the artificial Cs-137 in sediment. For this peruse, a 240 cm3 high-purity germanium reagent Type-B was used to quantify the levels in each sample with a relative accuracy of 50 %. The radioactive element K-40 is having a typical value of 12.5 Bq/kg. The concentrations of both Cu beside Zn in water samples is smaller if compared with values that quoted by the WHO, the US-EPA, and the EC. It was also found that the average levels for both Cd and Mn are found to be close to the internationally recommended levels. The water and sediments in the southern part of the canal contain higher concentrations of heavy metals and radioactive isotopes than in the rest of the canal.

Oral and dermal exposure to natural radionuclides and heavy metals in water and sediments of Nile River, Qena, southern Egypt

This study assessed the levels of natural radionuclides (226Ra, 232Th, and 40K) and heavy metals (Hg, Fe, Cr, As, Zn, Cu, Cd, and Pb) in surface water and sediment samples from the Nile River in Qena Governorate, southern Egypt, using a gamma-ray spectrometer, 3ʺ NaI (Tl) scintillation detector coupled with 1024 multi-channel analyzer, and an atomic absorption spectrometer. In surface water and sediments, the average activity concentrations of natural radionuclides were 40K (4.73 Bq L−1; 395.76 Bq kg−1) > 226Ra (0.41 Bq L−1; 18.14 Bq kg−1) > 232Th (0.30 Bq L−1; 17.98 Bq kg−1). The average heavy metal concentrations in surface water in µg L−1 were Fe (121.0) > Zn (33.80) > Cr (28.0) > Cu (8.62) > Pb (8.35) > As (1.19) > Hg (0.81) > Cd (0.12). In Nile sediments the concentrations in mg kg−1 were Fe (1670.0) > Zn (207.0) > Cr (29.40) > Cu (16.20) > Pb (4.32) > Hg (0.41) > Cd (0.31) > As (0.14). The heavy metal evaluation index (HMEI) calculations for water samples revealed that 31% of the samples were suitable for domestic use, while 69% were not. The geo-accumulation index, enrichment factor, and ecological risk factor for sediments were estimated, showing extreme enrichment for Hg and Zn with high ecological risk for Hg. Health risks for adults were evaluated due to oral and dermal exposure to Nile surface water and sediments from the study area, indicating minimal radiological risks and potential carcinogenic and non-carcinogenic risks from the metals.

Health risk assessment of uranium intake from private residential drinking groundwater facilities based on geological characteristics across the Republic of Korea

Groundwater contributes to an average of 8 % of the total water source capacity in the Republic of Korea. Hence, private residential households in rural areas in Korea are still using groundwater for drinking without any regular water quality inspection. This can increase the risk of exposure to natural radionuclides like uranium through drinking groundwater. This study investigated the uranium level in drinking groundwater all over the country by analyzing 11,451 samples from private residential drinking groundwater facilities and compared the exposure amount and its associated carcinogenic and non-carcinogenic risk based on the geological characteristics of the aquifer. Results yield that although the average hazard quotient (HQ) and excess cancer risk (ECR) of exposure to natural uranium through drinking groundwater were respectively below 1 and 1 × 10−6 and do not indicate a potential health hazard, significantly high HQ and ECR up to respectively 70 and 4 × 10−4 in samples where the aquifer is the Jurassic granite observed. Accordingly, regular water quality investigation and onsite treatment methods are required to provide healthy drinking water in such areas.

Gamma-radiation levels along the main Karakorum thrust area of Northern Pakistan

Abstract In this contribution, the distribution of naturally occurring radionuclides in the area around Main Karakoram Thrust (MKT) in Karakoram Range, North Pakistan is documented. Three natural radionuclides (226Ra, 232Th, and 40K) and one anthropogenic radionuclide (137Cs) were studied for their specific activities in 30 samples. The measurements were made by high resolution gamma-ray spectrometry. The sampling area is located in Gilgit Baltistan province of Pakistan at an altitude of 1838 m/6030 ft above sea level. MKT separates the Karakoram plate from the Kohistan-Ladakh Terranes and Indian Plate to the south. The specific activity varied as 4.5–56.5 Bq kg−1, 18.2–61.4 Bq kg−1, 1.4–19.6 Bq kg−1 and 51–1640 Bq kg−1 for 226Ra, 232Th, 137Cs and 40K, respectively. The average radium equivalent activity was 127.8 ± 45.9 Bq kg−1. The external hazard index was <1 for all samples and representative level index was <1 for majority of the samples. The average air absorbed dose rate was 60.9 ± 23.2 nGy h−1 corresponding to the outdoor effective dose rate of 73.7 ± 28.0 μSv y−1. These values were slightly higher than the world average values for air absorbed dose rate (51 nGy h−1) and outdoor annual effective dose rate (70 μSv y−1). The data revealed significant positive correlation between 226Ra and 40K. Principal component analysis revealed distribution patterns within the samples and identified three distinct groups. Data was also evaluated for the concentrations of uranium, thorium and potassium and their ratios.

Natural radioactivity measurements and evaluation of radiological hazards in the soil of an iron beneficiation plant in China

The specific activities of natural radionuclides, 232Th, 226Ra, and 40K, in a Chinese iron beneficiation plant and surrounding soil were analyzed with the high purity germanium gamma (HPGe) spectrometer in this study. Average specific activities of 238U, 232Th, 226Ra and 40K lower than the Chinese averages. To assess radiation impact, various indicators, radium equivalent index (Rae q), absorbed dose rate (DR), annual effective dose (AED), excess lifetime cancer risk (ELCR), external hazard index (Hex), internal hazard index (Hin) and activity utilization index (AUI), were calculated. Mean values were below international limits, indicating no significant health hazards for the local population. Statistical analyses, including skewness and kurtosis calculations, along with techniques like frequency distribution, Pearson's correlation analysis, box plots and cluster analysis, were applied to comprehensively assess distribution patterns and interrelationships among radiological parameters. In summary, there are no potential health hazards associated with the soil in the study region for people.

Development of a methodology for assessing radiological dose due to use of NORM sludge as fertilizer

In Europe, the general obligation to recycle drives for increased reuse of residues containing Naturally Occurring Radioactive Material (NORM). In agriculture, this has led to the reuse of sludge produced by groundwater filtration facilities as a means of fertilization. In the frame of the RadoNorm project, a methodology was developed for dose assessment of agricultural workers and other members of the public living near agricultural fields in which NORM-containing sludge is applied. Appropriate exposure scenarios were identified and modelled for each relevant NORM decay segment of both U-238 and Th-232 series, as well as for K-40. Dose assessments were performed using the software RESRAD-ONSITE with dose coefficients for external and internal exposure taken from the latest publications from the International Commission on Radiological Protection (ICRP). The objective was to develop a generic methodology to quantify exposure and to obtain screening values – so-called Operational Levels (OLs). These OLs pertain to the activity concentration of natural radionuclides (in terms of kBq kg−1) present in sludge that is reused in agriculture, for which dose criterion of 1 mSv year−1 is complied with. OLs can be used as screening tools by an authority/operator, even non-experts in the field of radiation protection.Results showed that the most critical decay segments are Ra-226+ and Ra-228+, for which OLs of the order of 1 kBq kg−1 were estimated. For all the other radionuclides, the calculated OLs are much higher than the activity concentrations typically found in sludge from water treatment facilities, and the radiological impact expected is well-below 1 mSv year−1. The methodology and results of this study could contribute to the update of the Clearance Levels and discharge levels reported in the European guidelines RP 122 Part II and RP 135, respectively.

Soil-to-organic Sangyod rice grain transfer factors (TF values) of natural and anthropogenic radionuclides in Phatthalung province, Thailand

The specific activities of natural (40K 226Ra and 232Th) and anthropogenic (137Cs) radionuclides in paddy soil and organic Sangyod rice grain were measured and analyzed in this study with an aim to determine the soil-to-organic Sangyod rice grain transfer factors (TF values) of all required radionuclides in Don Pradu sub-district, Pak Phayun district in Phatthalung province in the south of Thailand. The high purity germanium (HPGe) detector and gamma-ray spectrometry analysis system which were installed and used in advanced laboratory at TINT were used to conduct experiments to measure and analyze of all required radionuclides in this research. The average concentrations of 40K 226Ra, 232Th, and 137Cs in paddy soil were found to have a value of 657.30 ± 23.03, 180.01 ± 4.39, 162.02 ± 3.84 and < 1.81 Bq/kg respectively while in organic Sangyod rice grain, their values were 24.11 ± 2.01, 0.28 ± 0.07, 0.17 ± 0.06 and 0.10 ± 0.03 Bq/kg respectively. For TF values were calculated and found to be 0.037, 0.002, 0.001, and 0.055 for 40K, 226Ra, 232Th, and 137Cs, respectively. Furthermore, four important radiological hazard indices which are gamma-absorbed dose rate (D), radium equivalent activity (Raeq), external hazard index (Hex) and annual external effective dose rate (AEDout) were also evaluated by using the average values of 40K, 226Ra and 232Th. In addition, by using the AEDout value, the excess lifetime cancer risk (ELCR (outdoor)) in paddy soil in the study area would be also studied, evaluated and presented. Moreover, the evaluated TF values of required radionuclides were higher than that reported by the International Atomic Energy Agency (IAEA) in 2010 but the values were much lower than those in the study in Malaysia.

Effects of Natural Radioactivity of Some Chemical and Organic Fertilizers on Gonads in Iraqi Kufa Markets

This study assessed the hazard indicators of common chemical and organic fertilizers widely available in the markets of Najaf Governorate, Iraq. The concentrations of natural radionuclides were measured in thirteen types of fertilizers by Gamma spectrum using NaI(Tl) (3*3) detector. The average radioactivity of the nuclides 226Ra, 232Th, and 40K was (48.91, 37.04, and 702.4675) Bq.kg-1, respectively, for (Di-Aluminum Phosphate) the chemical fertilizers of the type (DAP) and the (nitrogen, phosphorus, and potassium) chemical fertilizers of the type (NPK) the average radioactivity of the nuclides 226Ra, 232Th, and 40K were (35.78, 42.356 and 1519.653) Bq.kg-1, respectively, while the average radioactivity of the organic fertilizers (Orga.) were 55.153, 23.148 and 1451.258 for the three studied nuclei. As for the average values for radium equivalent were 155.967, 213.363, and 200.0023 (Bq.kg-1) for (DAP), (NPK) and organic fertilizers, respectively. The values of the external severity index (Hex), gamma radiation hazard index (Iγ), and representative alpha index (Iα) were within the permissible limits determined by the UNCEAR 2000. The highest value of total annual effective dose equivalent(TAED) was 1.468 mSv.y-1, the lowest value was 0.302 mSv.y-1, and the mean values were 0.722 mSv.y-1. In contrast, the highest value for annual gonadal dose equivalent(AGED) was 1392.527 μSv.y-1, the lowest value was 275.361 μSv.y-1, and the average values for all models were 672.135 μSv.y-1. The Excess Lifetime Cancer Risk (ELCR), the highest value was 4.039 × 10-3, the lowest value was 0.833× 10-3, and the average value was 1.988× 10-3 for all fertilizers. The Pearson correlation between radioactive variables and cluster analysis was recognized for the three types of fertilizer samples despite it not being widely accepted. The study can be considered preliminary data for subsequent studies.

Радиационная ситуация района расположения плавучей атомной теплоэлектростанции «Академик Ломоносов» в начальный период эксплуатации

The article considers the issues of energy supply to remote sparsely populated Arctic regions of the Russian Federation through the construction of low-capacity nuclear power plants. The effectiveness of this approach is demonstrated by the successful commissioning in 2019 of a unique floating power plant in the town of Pevek (FNPP Akademik Lomonosov). At the same time, the operation of such facilities raises questions from the local population about possible radioactive contamination of the territory. The absence of a negative impact of FNPP can be confirmed by comparing the radiation characteristics before and after commissioning, as well as by direct measurements of the soil radionuclide composition in the zone of possible impact. To search for changes in the radioecological situation in 2021, screening studies were carried out at the plant location area. An analysis of the monitoring data for radioactive fallout and dose rate in Pevek showed that external exposure from the surface of soil and soil is due only to natural radionuclides of the decay chains of uranium, thorium and 40K. Artificial radionuclides characteristic of NPP emissions were not found in the surveyed areas. The range of values and maximum dose rate levels (µSv/h) before and after commissioning of the FNPP do not differ from each other and coincide with the results of the performed screening assessment of the radiation situation. The results were discussed with the residents of Pevek. The results of the study make it possible to inform the public about the absence of changes in the radiation situation at the FNPP location area in the first years of operation.

The effect of natural radionuclides on soil: Review

People are affected by nature radiation in several various forms depending on elements of the present radioactive nature in any location; such researchers investigating natural environmental radiation and radionuclides checks are being conducted by background on the soil to detect ambient radioactivity. Stages of radioactivity could use for evaluating the general average of portion, tainting of radiation and various anticipate in ecological radiation brought about by atomic mishaps agricultural activities, the transmission of radiation from soil to agriculture, crops, and other persons more active.

Investigation and assessment of natural radioactivity in commercial animal feeds in Texas

Commercial animal feed in Texas was characterized by determining natural gamma emitters including 40K,137Cs, and Uranium (235U and 238U) and Thorium (232Th) series to obtain basic radioactivity values. The measured activity concentration of natural radionuclides in animal feed was low enough for safe consumption by animal and largely depended on the type of animal feed.40K was the predominant radionuclide showing the highest activity concentration in animal feed. The radioactivity concentration of 214 Bi and 214Pb in 238U decay series was 1.39 and 1.33 Bq/kg in corn, respectively, lower than in other animal feed types. On the other hand, the vitamin/mineral mix samples showed higher concentrations of 214 Bi (9.04 Bq/kg) and 214Pb (10.19 Bq/kg). Beef cattle feed, poultry feed, and vitamin/mineral mix exhibited higher activity concentration of 228Ac and 212Pb in 232Th decay series. Gamma radionuclides appeared to be highly and significantly correlated within each decay series. 235U was present at low levels in all feed samples while the anthropogenic radionuclide of 137Cs was not detected irrespective of the type of animal feed. This study highlights an importance of establishing a current baseline of radioactivity concentration in animal feed in Texas in which the largest animal feed consumption in the US exists.

Estimation of transfer factor from soil to cassava in Ethiope East, Delta State, Nigeria

Cassava is a very important staple food crop in Delta state. The aim of this research is to assess the activity concentration level and determine the transfer factor of radionuclide from soil to cassava in Ethiope Local Government Area of Delta state, Nigeria. The activity concentration of 40K, 238U and 232Th in soil and cassava samples collected from the study area were analysed using gamma spectrometry. A lead-shielded 3 x 3 inch coaxial type Sodium Iodide Thallium [NaI(TI)] doped detector crystal (Model No. 802 series, Canberra Inc.) coupled to a Canberra series multichannel Analyzer (MCA) (Model N0.1104) through a preamplifier was used. The results of the activity concentration in soil samples indicate that, 40K has the highest mean activity concentration ((38.66 ± 3.69) BqKg−1) with the highest value ((62.47 ± 5.67) BqKg−1) recorded at E2. The mean activity concentrations of 238U and 232Th are 3.65 ± 0.90 BqKg−1 and 0.46 ± 0.05 BqKg−1respectively. The peak values of 238U and 232Th are 5.07 ± 1.17 BqKg−1 and 0.98 ± 0.11 BqKg−1. From cassava, 40K varies from 75.06 to 200.08 BqKg−1 with the highest mean activity concentration of 99.62 ± 8.32 BqKg−1 and 200.08 ± 14.90 BqKg−1 as the highest value noted at C5. The mean activity concentrations of 238U and 232Th are 3.89 ± 0.93 BqKg−1 and 0.81 ± 0.09 BqKg−1 respectively. The maximum values of 238U and 232Th determined from the computation from cassava samples are 11.10 ± 2.48 BqKg−1 and 1.70 ± 0.18 BqKg−1. The results of this study show that the activity concentration of 40K, 238U and 232Th in the study area are lower than world average values of 420, 30 and 35 BqKg-1 in soil and cassava respectively, and it is therefore not harmful if consumed. The mean transfer factor of 40K, 238U and 232Th from soil to cassava are 3.12 ± 0.44, 0.95 ± 0.31 and 2.96 ± 0.91 respectively. The range of values of 40K, 238U and 232Th varied as 1.41 to 5.82, BDL to 2.98 and 0.21 to 9.35 correspondingly. Peak values of the TF were noted as 5.82 for 40K at E8, C8, 2.98 for 238U at at E9, C9 and 9.35 for 232Th at E9, C9. The high value of TR is accredited to the richness of the organic matter in the soil. The quick recycling of natural radionuclides through the soil-cassava suggests the presence of an internal cycling that help the build-up of the natural radionuclides.

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.

Radiation risk assessment of quarry pit soil as construction material in Abeokuta, Nigeria: implications for environmental and public health

ABSTRACT Environmental and health risks posed by radionuclides in quarry pit soils are of great concern in environmental health monitoring. The current investigation was aimed at determining the natural radionuclide activity concentration (in Bq kg–1) of the understudied quarry pit granules used as construction materials. The collection and preparation of pit soil samples from Abeokuta quarry sites were done using standard methods, analysis of radiological parameters was carried out using hyperpure germanium (HPGe) spectrometer. Specific activity concentrations of 226Ra, 232Th, and 40K were measured. The values obtained were greater than the world weighted average of 35, 30, and 400 Bq kg–1 for 226Ra, 232Th, and 40K, respectively. The absorbed dose, the annual effective dose, and the radium equivalent were calculated and demonstrated significant values. The radionuclide content of the samples is relatively high and the use of pit soils as a building material, therefore, raises radiological concerns for dwellers in this area and requires periodic monitoring and undergoing a radiation protection program.