Activity Concentrations Of 226Ra Research Articles

Natural Radioactivity Levels and Some Elements Concentrations in Bauxite Ore Deposit of Az Zobirah Mine-Al Qassim - Saudi Arabia

The activity concentrations of (NORM) radionuclides 226Ra, 232Th and 40K were determined in Bauxite of AzZobirah mine–AlQassim Saudi Arabia using High Pure Germanium detector (HPGe). Bauxite samples concentrations ranged from 72.40±0.07 to 227.21±0.14, from 119.70±0.20 to 310.30±0.10 and from 81.00±0.11to 119.00±0.01 and the average were 67.44, 171.77 and 96.94 Bq/ kg for 226Ra,232Th and 40K respectively., respectively. 226Ra and 232Th average values are higher than the world value 50 and 50 Bq/Kg, while for 40K average is less than the world value 500 226 Bq/ kg. 226Ra concentrations are less than of 232Th, this variations refer to the change and nature in the geological processes in this area such as the 226Ra being more soluble in water. The radiological Radiation hazard indices (Raeq), (D), (AEDE), (Hex), (Hin) were found higher than the world values. By AA Analysis, The concentration average values for nine elements (Al, Ca, Fe, K, Mg, Bi, Pb, Th, U) showed that, the major element is Al (20.50%), minor element is Fe (5.34%), trace elements Ca, K and Mg are (0.05, 0.04 and 0.43) % respectively. Bi is not detected, Pb, Th and U are trace elements with low concentration values (0.0006, 0.0043 and 0.0027) respectively. Bauxite has been most used in industry for producing aluminium. So, the level of pollution, the risk of the activity concentrations of (NORM) and the unacceptable limits levels of health hazard due to natural radioactivity in this area must be taken into consideration. The data will be saved as database to control the possible change in the environment area due to human activities in future.

Soil radioactivity levels and radiation exposure to the population in Aswan and Abu Simbel areas, South of Egypt

Gamma-ray spectrometer and Lucas cell were used to evaluate the activity concentrations of 226Ra, 232Th, 40K, and 222Rn mass exhalation rates for 37 topsoil samples from different sites in Aswan city, Aswan-Abu Simbel highway, and Abu Simbel village, south of Egypt. The average activity concentration of 226Ra, 232Th, and 40K was 23.3 ± 1.7, 21.1 ± 1.2, and 283.4 ± 22.3; 21.2 ± 1.7, 15.2 ± 1.0, and 89.4 ± 10.5; 29.0 ± 2.2, 26.3 ± 1.5, and 79.5 ± 9.7 Bq kg−1 for soil from Aswan city; Aswan-Abu Simbel highway; and Abu Simbel village, respectively. Activity ratios for the studied radionuclides were calculated, and 232Th/226Ra ratios in most of the sampling sites were <1.1 (natural equilibrium ratio). The mass ratio of Th/K was computed, and the results showed the presence of three main types of clay minerals (montmorillonite, kaolinite, and heavy thorium-bearing minerals) in the studied areas. Radon measurements showed that soil from Aswan city has the highest average value of 222Rn mass exhalation rate (20.6 ± 1.7 mBq kg−1 h−1). The ambient dose equivalent rates were measured in situ using the portable survey meter, and the obtained values showed no significant differences between the studied areas. In general, the results indicate that the studied areas can be considered as areas with normal background radiation levels, and therefore the risks of exposure to natural radiation are minimal.

Measurement of Activity Concentration of 40K, 226Ra and 232Th in Commercial Wall Paints Used in Nigeria and Inherent Radiological Hazards

Ionizing radiations from building materials portend serious health risk to atoms and molecules of body cells by damaging tissues and altering the DNA in genes. In this study, the measurement of radioactivity concentration of 40K, 226Ra and 232Th to determine inherent radiological hazards in major brands of commercial wall paints used in Nigeria was carried out. Twenty paint samples were selected based on the popularity and quantity of sales of these paints’ brands as obtained from oral interview with these paints’ marketers. A NaI (Tl) detector (76×76 mm) was employed in the measurements. High mean levels of the radioactivity of 40K, 226Ra and 232Th were observed in emulsion paints 174.73, 58.18 and 56.98 Bq/kg while oil paints gave lower values of 119.66, 44.66 and 37.86 Bq/kg for 40K, 226Ra and 232Th respectively. From results obtained, most of the emulsion and oil paints available in Nigeria present low level of radioactivity concentration which does not pose significant radiological risk to user population. However, average excess lifetime cancer risk of these paints gave a value higher than the recommended limit. Based on this, regulation, quality control and constant monitoring of raw materials used for paint production in Nigeria is highly advised.

Radiological assessment of urban soil samples in the residents of a central Anatolian volcanic province, Turkey

ABSTRACT The concentration of natural and anthropogenic radionuclides, emanation fraction (EF), and mass (χM) and area (χA) exhalation rate of 222Rn in urban soil samples collected from dwelling areas in Nevşehir city located in a region known as the central Anatolian volcanic province of Turkey were determined using gamma-ray spectroscopy. The average activity concentrations of 226Ra, 228Ra, 40K and 137Cs were measured as 60.2 ± 3.8, 50.1 ± 2.8, 631.0 ± 29.7 and 5.5 ± 0.4 Bq/kg, respectively. The average concentration of 222Rn in soil and air was estimated as 27 kBq/m3 and 84 Bq/m3, respectively. The average values of EF, χM and χA were found as 20%, 25.4 μBq/kg⋅s and 20.2 mBq/m2⋅s, respectively. The average values of outdoor absorbed gamma dose rate, external and internal annual effective dose and lifetime cancer risk estimated for radiological assessment were found as 85 nGy/h, 104 µSv/y, 797 µSv/y and 4.1 × 10−4, respectively.

Radioactivity distribution in soil samples of the Baba Gurgur dome of Kirkuk oil field in Iraq

ABSTRACT This work presents a study of radioactivity in soil samples from oil well sites of Baba Gurgur dome of Kirkuk oil field using a high-purity germanium (HPGe) detector and spectroscopy system. The activity concentration (Bq kg−1) of 226Ra, 232Th, 40K and 137Cs varied between 26.4–98, 10.8–55.2, 239–729, and 2.40–7.20, respectively. The results have been compared with the average worldwide values. The hazard indices have also been calculated. The radium equivalent activity (Raeq) was 131.04 Bq kg−1, the absorbed gamma dose rate (D) was 62.04 nGy h−1, the annual effective dose rate (AEDE) outdoor and indoor were 0.08 mSv y−1 and 0.30 mSv y−1, respectively, the external hazard (Hex) was 0.35, the internal hazard (Hin) was 0.51, the Gamma radiation representative level Index (Iγ) was 0.96, and excess lifetime cancer risk was 0.30 × 10−3. Our results of some sites were found to be higher than the allowable worldwide values. Statistical data including: Mean, Median, Std. Deviation, kurtosis, skewness, box plot, frequency distribution, Quantile-quantile (Q-Q) plots, Pearson’s correlation coefficient analysis, principal component analysis (PCA), and cluster analysis were calculated and carried out to explain our results.

Levels of Cs-137, natural radionuclides and heavy metals in soil of Al-Negila area, Northwestern Coast of Egypt: distribution and risk assessment

ABSTRACT Radionuclides and heavy metals/metalloids content in soils and shore sediments of Al-Negila area (Matrouh, Egypt) were determined to assess the associated environmental risks. A total of 46 soil and shore sediment samples were collected and analysed for natural and man-made radionuclides (238U series, 232Th series, 40K and 137Cs) and heavy metals/metalloids (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Si, Sr, Zn, and Hg). Within the study area, the soil and shore sediments are mainly calcareous with sandy, sandy clay and silty clay sized textures. The radionuclides and metals/metalloids concentrations in the soil were higher than those in the shore sediments, meanwhile, they are within the safe world average values. The estimated average (±SD) activity concentrations of 226Ra, 228Ra, 40K and 137Cs were 20.3 ± 5.3, 17.8 ± 6.3, 353.1 ± 129.8, and 2.7 ± 2.7 Bq/kg, respectively. The activity concentration of 137Cs is characterised by the greatest variability characterising the fallout deposited radionuclides. The estimated average values of Raeq (72.9 ± 23.7 Bq/kg), air absorbed gamma dose rate (34.9 ± 11.4 nGy/h), annual effective dose (42.8 ± 14.0 µSv/y), and external hazard index (0.2 ± 0.1) are lower than the international averages reported by UNSCEAR 2008. The average concentrations (mg/kg) of heavy metals/metalloids in soil samples decrease in the following order: Mn (129.8) > Sr (95.0) > Si (28.8) > Ba (25.7) > Zn (25.1) > Cr (17.6) > B (10.0) > Ni (3.9) > Cu (3.3) > Co (0.5) > Cd (0.007) > Hg (7.0 µg/kg). According to the classes of pollution load and contamination degree indices, soils and shore sediments of Al-Negila area are generally uncontaminated. However, a few sampling sites were considered moderately contaminated with B, Cd, and Sr. The radionuclides and heavy metal/metalloid contents in the soil and shore sediments of the area should be observed and assessed regularly, especially for 137Cs.

Natural Radionuclide Levels and Radiological Hazards of Khour Abalea Mineralized Pegmatites, Southeastern Desert, Egypt

Arranged from oldest to youngest, the main granitic rock units exposed in Khour Abalea are metagabbros, cataclastic rocks, ophiolitic melange, granitic rocks, pegmatite and lamprophyre dykes. The presence of radioactivity associated with the heavy bearing minerals in construction materials—like granite—increased interest in the extraction process. As it turns out, granitic rocks play an important economic part in the examination of an area’s surroundings. The radionuclide content is measured by using an NaI (Tl)-detector. In the mineralized pegmatites, U (326 to 2667 ppm), Th (562 to 4010 ppm), RaeU (495 to 1544 ppm) and K (1.38 to 9.12%) ranged considerably with an average of 1700 ppm, 2881.86 ppm, 1171.82 ppm and 5.04%, respectively. Relationships among radioelements clarify that radioactive mineralization in the studied pegmatites is magmatic and hydrothermal. A positive equilibrium condition confirms uranium addition to the studied rocks. This study determined 226Ra, 232Th and 40K activity concentrations in pegmatites samples and assessed the radiological risks associated with these rocks. The activity concentrations of 226Ra (13,176 ± 4394 Bq kg−1), 232Th (11,883 ± 5644 Bq kg−1) and 40K (1573 ± 607 Bq kg−1) in pegmatites samples (P) are greater than the global average. The high activity of the mineralized pegmatite is mainly attributed to the presence of uranium mineral (autunite), uranophane, kasolite and carnotite, thorium minerals (thorite, thorianite and uranothorite) as well as accessories minerals—such as zircon and monazite. To assess the dangerous effects of pegmatites in the studied area, various radiological hazard factors (external, internal hazard indices, radium equivalent activity and annual effective dose) are estimated. The investigated samples almost surpassed the recommended allowable thresholds for all of the environmental factors.

Radon and thoron concentrations in the southwest region of Angola: dose assessment and implications for risk mapping.

Indoor radon (222Rn) and thoron (220Rn) are the most important natural sources of ionizing radiation to the public. Radiological studies that assess simultaneously 222Rn and 220Rn, and their controlling factors are particularly scarce in African countries. Hence, we conducted a survey of indoor 222Rn and 220Rn in buildings located in the SW region of Angola. Bedrock samples were also collected, and a borehole was executed to assess 226Ra and 224Ra activity concentration, 222Rn and 220Rn exhalation and emanation potential in the surface and at depth. The aim of this study was to determine the factors (geological and anthropogenic) that may influence the annual inhalation dose (AID) received by the population. Overall, the sum of indoor radon and indoor thoron concentrations, labelled the total indoor radon concentration (TIRC), was higher than 300Bq/m3 in only 5% of the buildings studied. The contribution of 220Rn to the TIRC averaged 35% but may reach 95%, demonstrating the relevance of discriminating radon and thoron in indoor radon surveys. Indoor 222Rn and 220Rn were not correlated, indicating both must be estimated to properly assess the AID. Indoor 220Rn concentrations were statistically different according to the building materials and type of usage. Higher 222Rn and 220Rn concentrations were observed in dwellings compared to workplaces. The median AID estimated for dwellings was 1.50mSv/y compared to 0.26mSv/y for workplaces, which are lower than the estimated average radiation exposure due to natural sources of 2.4mSv/y. AID values higher than 1mSv/y effective dose threshold established in the Council Directive 2013/59/EURATOM for the purpose of radiation protection in workplaces were observed in 12% of the workplaces studied suggesting the need for mitigation measures in those buildings. The analysis of bedrock samples revealed statistically significant correlations between 224 and 226Ra activity concentration, and 220Rn and 222Rn exhalation and emanation potential. The borehole samples indicated a strong influence of weathering processes in the distribution of radioisotopes. The highest 226Ra and 224Ra activity concentration, and 222Rn and 220Rn exhaled per unit mass, TIRC and AID were observed in association with A-type red granites and porphyries. We conclude that both geological and anthropic factors, such as the type of building usage and building materials, must be considered in dose assessment studies and for the development of risk maps.

Radioactive risk assessment of beach sand along the coastline of Mediterranean Sea at El-Arish area, North Sinai, Egypt

Beach sand includes various levels of natural radioactivity, which can cause health effects. The natural radioactivity was measured in the beach sand along the coastline of the Mediterranean Sea at the east of the El-Arish area, Egypt. Using the HPGe spectrometer, the contribution of radionuclides 226Ra, 232Th and 40K in the gamma emitted radiation illustrated that the 226Ra, 232Th and 40K activity concentrations are 8.8 ± 3.9, 30.8 ± 12.2 and 106.9 ± 46.8 Bq kg−1, respectively, which is lower than the reported worldwide limit 33, 45 and 412 Bq kg−1. The radioactive hazards associated with the beach sand along the coastline of the Mediterranean Sea at the east of the El-Arish area were investigated. The obtained results among the radiological hazard parameters, the radium equivalent content (Raeq), the absorbed dose rate (Dair), annual effective dose (AED), external (Hex) and internal (Hin) hazard indices were estimated. Moreover, the excess lifetime cancer risk (ELCR) and the annual gonadal dose equivalent (AGDE) were also computed and illustrated their values less than the recommended levels. Multivariate statistical approaches like Pearson correlation, the principal component analysis (PCA) and the hierarchical cluster analysis (HCA) were applied to investigate the correlation between the radionuclides and the corresponding radiological hazard variables. Based on the statistical analysis, the 226Ra and 232Th mainly contribute to the radioactive risk of beach sand. Finally, no significant risk of the public associated with utilizing beach sand in building materials.

Measurement of natural radiation, calculation of radiation doses of agricultural environmental samples in the western region - Kingdom of Saudi Arabia

The activity concentrations of the NORM were measured in thirty samples of plant cultures in agricultural soil irrigated with groundwater from different locations in the Makkah region in Saudi Arabia, using a high purity germanium detector HPGe system. The mean values of the activity concentrations for 226Ra, 232Th, and 40K were found in plants samples 10.41, 1.92, and 4154.92 in Bq. kg−1, for agricultural soil samples were 18.11, 16.12, and 1603.73 Bq. kg−1 respectively, and the irrigation water samples were found 1.57, 0.58, and 118.44 Bq. l−1 respectively. The mean values of Raeq, dose rate, annual effective dose, hazard indices Hex and Hin were 333.09 Bq. kg−1, 179.23 nGy h−1, 1.09 mSv.y−1, 0.89 and 0.92 respectively for plant samples. The gamma doses were higher than world limit values and the Hex and Hin were less unity. The mean values of annual effective doses for ingestion of radionuclides in the plants samples were 2.12 mSv.y−1 for children and 1.86 mSv.y−1 for adults, these results were higher than the world values. These results indicate that, the highest doses refer to the samples location in farm 1, while the lowest values were in farm 3 and farm 6, while the other farms were relatively high than recommended dose values. So, samples of soil, water and plant must be studied in the farm 1 for the highest results of the annual effective doses mSv.y−1 of ingestion of radionuclides in the plants samples for children and adults.

Distribution of radionuclides in vertical profile and physico – chemical parameters of soil in Somwarpet taluk, Coorg district, Karnataka state, India

ABSTRACT The distribution of 226Ra, 232Th, 40K, 210Po and 210Pb radionuclides in the illuviated soils of Somwarpet taluk, Coorg district of Karnataka state are investigated. In a vertical profile, soil samples were collected and the activity concentrations of these radionuclides were determined. The activity concentration of 210Po and 210Pb was determined using the radioanalytical method. The activity concentration of 226Ra, 232Th and 40K radionuclides in the lowest layer or the illuviated horizon of the vertical profile were found to be highest, due to accumulation of organic matter and clay. The average 210Po and 210Pb activity concentration is 12.49 Bq kg−1 and 33.94 Bq kg−1 in the top layer of the soil, 3.01 Bq kg−1 and 16.96 Bq kg−1 in the second layer, and 1.53 Bq kg−1 and 7.11 Bq kg−1 in the third layer respectively, which is high in the top surface of the soil. The determined physico-chemical parameters and the dependence of radionuclides were analysed using Pearson correlation analysis, which shows that insignificant associations could be attributable to changes in physico-chemical characteristics of soil in different sampling locations.

Estimation of activity concentrations of radionuclides and their hazard indices in coastal plain sand region of Ogun state

Assessment of natural background radionuclides emanating from the subsurface geological features was carried out with the use of gamma-ray spectrometry at various locations at one of the secondary school in Canaan land, Ota, Ogun State. The activity concentrations of 226Ra, 232Th and 40K were revealed to be 12.66 ± 0.76–42.33 ± 1.37, 44.96 ± 1.41–128.70 ± 1.56, 31.30 ± 1.18–453.85 ± 2.43 Bq kg−1 respectively. The mean value of 232Th reported higher than the world reference standard of 50 Bq kg−1. Moreover, the stations closest to the school’s laboratory were noticed to be prone to more gamma radiations than the other buildings in the school. Similarly, the results of the radiological parameters estimated varied between 86.04–243.7 Bq kg−1, 40.02–115.4 nGy h−1, 0.049–0.142 mSv y−1 and 0.232–0.658 for Raeq, D(out), AEDE and Hex, respectively. Although, the results of the radiological parameters did not exceed the world safe limits, higher values of these parameters were reported at some stations closer to the school laboratory. It can be concluded that the school laboratory is prone to more gamma radiation than the class rooms and the administrative block. Therefore, the laboratory instructors and staff, who spend longer time in the laboratory, are more liable to the health risk that could result from years of exposure to gamma radiation in the laboratory.

Best practices for predictions of radionuclide activity concentrations and total absorbed dose rates to freshwater organisms exposed to uranium mining/milling

Predictions of radionuclide dose rates to freshwater organisms can be used to evaluate the radiological environmental impacts of releases from uranium mining and milling projects. These predictions help inform decisions on the implementation of mitigation measures. The objective of this study was to identify how dose rate modelling could be improved to reduce uncertainty in predictions to non-human biota. For this purpose, we modelled the activity concentrations of 210Pb, 210Po, 226Ra, 230Th, and 238U downstream of uranium mines and mills in northern Saskatchewan, Canada, together with associated weighted absorbed dose rates for a freshwater food chain using measured activity concentrations in water and sediments. Differences in predictions of radionuclide activity concentrations occurred mainly from the different default partition coefficient and concentration ratio values from one model to another and including all or only some 238U decay daughters in the dose rate assessments. Consequently, we recommend a standardized best-practice approach to calculate weighted absorbed dose rates to freshwater biota whether a facility is at the planning, operating or decommissioned stage. At the initial planning stage, the best-practice approach recommend using conservative site-specific baseline activity concentrations in water, sediments and organisms and predict conservative incremental activity concentrations in these media by selecting concentration ratios based on species similarity and similar water quality conditions to reduce the uncertainty in dose rate calculations. At the operating and decommissioned stages, the best-practice approach recommends relying on measured activity concentrations in water, sediment, fish tissue and whole-body of small organisms to further reduce uncertainty in dose rate estimates. This approach would allow for more realistic but still conservative dose assessments when evaluating impacts from uranium mining projects and making decision on adequate controls of releases.

Radioactivity in Future Phosphogypsum: New predictions based on estimates of ‘Peak P’ and rock phosphate resources

Global food supplies currently depend on producing inorganic P fertilisers from a finite reserve of rock phosphate (RP). P fertilisers are themselves significant pollutants but their production from RP also leaves a phosphogypsum (PG) by-product that is sufficiently radioactive that its reuse is restricted. PG is mostly accumulated in open ‘stacks’ that make up a significant proportion of all Technologically Enhanced Naturally-Occurring Radioactive Material (TENORM) waste. Using lower and upper estimates of current RP reserves, historic production, and Hubbert's logistic function-based ‘peak theory’, lower and upper boundaries for possible RP production were predicted to the year 2100. The ‘low’ boundary scenario had a production peak of c.350 Mt/a RP in c.2050 followed by a steep decline. The ‘high’ boundary scenario had a production peak of c.1200 Mt/a RP in about 2090. Future trends in P demand for food production were used to predict a possible, demand-driven, RP production scenario until 2100 which peaked at a demand of c.620 Mt/a RP and was within possible production boundaries. An RP:P ratio of 5.62:1 and PG:P fertiliser ratio of 4:1 was used to calculate that this predicted demand-driven scenario would ultimately produce nearly 350 Mt/a of PG and a cumulative total of c.30 Gt by 2100. Average PG activity concentrations of 226Ra (650 Bq/kg), 210Po (300 Bq/kg) and 230Th (100 Bq/kg) give a total of c.30 PBq radioactivity in this by-product. Humanity is faced with a phosphorus dilemma – if the low production scenario unfolds it threatens food security but if predicted demand for P is met from RP the environmental challenges arising from P fertiliser use will be profound and exacerbated by a significant radioactive waste challenge. The estimates reported here show that studies of environmental radioactivity have a role to play in debates about P resources and global food security.

Treatment for removing radium in soil and groundwater

The results of 226Ra activity concentration measurements in 50 soil and groundwater samples in Ninh Son region, Vietnam were evaluated in the present study. Average activity concentration in the soils was significantly higher than the worldwide average concentration in soils published by UNSCEAR, 2008. 90% of groundwater samples had concentrations of 226Ra that were higher than the USEPA drinking water standard. The results showed that there was a linear correlation between the 226Ra radioactivity in the soils and the concentration of 226Ra in the groundwater samples. The procedure for removal of 226Ra from soil and groundwater samples was built upon the chemistry behavior of radium. 226Ra in contaminated groundwater samples was removed by using MnO2 fiber. The removal efficiency of 226Ra reached ∼ 91% for the groundwater samples and ∼ 70% for the soil samples. Chemical removal of 226Ra from soils was investigated using a three-step extraction procedure (Easily leachable and exchangeable, Acid-reducible, and Oxidisable-organic). A moderate mobility of 226Ra (22–52%) was noted and mainly found in acid-reducible fractions, which suggests that 226Ra is mainly bound to Fe/Mn oxides and hydroxides. A multiple regression indicates that the 226Ra removal efficiency appears to be significantly dependent on Fe/Mn and organic matter content.

Radium in New Zealand agricultural soils: Crop uptake and estimation of current and future ionising radiation dose

Crop uptake of 226Ra over a range of key New Zealand agricultural and horticultural growing areas was analysed to establish the dietary implications of an increase in soil 226Ra activity concentrations. Thirty crop samples, covering both feed and food commodities, were quantified for 226Ra activity concentrations, and concentration ratio (CRs) from the soil activity were calculated. The calculated CRs correlated with international default values for estimating crop uptake. Variation in CRs established that there was no increase in the crop activity concentration, relative to soil 226Ra from pasture foliage at a fertiliser impacted site, with a gradient of soil 226Ra activity concentrations. Based on the calculated CRs, the upper bound of the theoretical range of dietary exposures to 226Ra was 78.1 μSv/yr for teenage boys. Future forecasting of the increased dietary dose of 226Ra that might occur at the current soil loading rate, based on current fertiliser activity concentrations, confirmed that long-term loading of soil with 226Ra is unlikely to present a dietary risk. The forecast model calculated that the increase in dietary ionising radiation burden is unlikely to reach thresholds requiring regulatory intervention for two millennia.

Evaluation of natural radionuclides distribution in beach sands of Cox’s bazar sea beach, Bangladesh, using multivariate statistical technique

ABSTRACT The distribution of natural series radionuclides 226Ra, 232Th and non-series 40K in the heavy mineral-rich beach sands of highly touristic areas of Cox’s Bazar sea beach has been studied. The study is made to evaluate the gamma radiation exposure to individuals with an aim to establish reference data for the presence of naturally occurring radionuclides. The present study reports the probable first attempt of detail and systematic work in the study areas for estimation of activity concentration in the recent beach sand samples. Radiometric analysis was performed using gamma ray spectroscopy system based on HPGe detector. The mean activity levels of 226Ra, 232Th and 40K in Laboni beach sands were ranged from 255.69±64.57, 336.83±93.96 and 1785.91±89.60 Bq kg-1, respectively. While in Kolatoli beach sands, the respective values were 166.42±35.99, 157.35±35.90 and 1894.42±74.07Bq kg-1, respectively. The mean values of 226Ra and 232Th concentrations in the investigated beach sands were estimated to be very much higher than the corresponding world average values and comparable to those found in high background radiation areas in the world. The heavy minerals seem to control the activity concentrations of 226Ra and 232Th in sand samples, showing some variances based on uranium and thorium bearing minerals. Various radiation health hazard indicators were found to be extremely higher when compared to the recommended values. Hence, heavy mineral-rich sands may pose a significant radiological health risk to the people. The descriptive statistics indicating the radionuclides of 226Ra, 232Th and 40K are uniformly and symmetrically distributed in the Cox’s bazar beach sand. Multivariate statistical analysis showing the radioactivity and estimated radiological parameters are strongly positively correlated with 226Ra and 232Th, while weakly correlated with 40K, signifying that radiological risk is mainly associated and controlled by the radioactivity levels of uranium and thorium series radionuclides.

Refining the conceptual model for radionuclide mobility in groundwater in the vicinity of a Hungarian granitic complex using geochemical modeling

Groundwater is an important freshwater resource, which can be affected by geogenic radionuclide contamination. To make decisions regarding the use and management of groundwater, understanding the controls of radionuclide mobility is critical. In the southern foreland of a granitic outcrop in Hungary, high gross alpha activity concentration was measured in drinking water wells, related probably to the presence of uranium. It has been suggested that understanding of the groundwater flow system may be a key aspect to understand uranium mobility in groundwater. The goal of the present work was to elucidate the conceptual model of radionuclide mobility in the study area, focusing in particular on the geochemical controls of uranium. For this purpose, water samples were collected and nuclide-specific measurements for 226Ra and radon isotopes were carried out, in addition to 234U+238U measurements, to increase the range of radionuclides and better understand their mobility. A geochemical modeling analysis involving redox-controlling kinetic reactions and a surface complexation model was developed to support the conceptual model. The results from the sampling indicate that excess of 234U+238U (3–753 mBq L−1) contribute to the natural radioactivity measured in drinking water to a large degree. 226Ra was measured in relatively low activity concentrations (<5–63 mBq L−1) with the exception of three specific wells. Notable radon activity concentration was measured in the springwaters from Velence Hills (1.01–3.14 × 105 mBq L−1) and in interrelation with the highest (285–695 mBq L−1) 226Ra activity concentrations. The geochemical model suggests that uranium distribution is sensitive to redox changes in the aquifer. Its mobility in groundwater depends on the residence time of groundwater compared to the reaction time controlling the consumption of oxidizing species. The longer the flow path from the recharge point to an observation point where U is measured, the more likely it is that reducing conditions will be found in the aquifer and the elemental concentration U will be low.

Distributions and Risk Assessment of the Natural Radionuclides in the Soil of Shoubra El Kheima, South Nile Delta, Egypt

Due to heightening concern about radiation hazards protection, activity concentrations of 226Ra, 232Th, 40K in forty soil samples collected from Shoubra El Kheima in the South Nile Delta were measured using gamma-ray spectrometry. The mean activity concentrations of 226Ra and 40K were higher in 20% of the considered samples than the world average values. A comprehensive comparison with up-to-date data was carried out. Spatial distribution maps of the measured radionuclides and radiological parameters were generated. The distributions of natural radionuclides were influenced by the soil organic matter, clay content, and scavenger metals oxides, as well as differences in the physical and chemical attributes and solubility of these radionuclides. The results revealed that industrial activity and agricultural practices in the study area caused an incremental increase in 226Ra and 40K activity concentrations. It can be deduced that although there are intensive industrial activities in this area, the natural radiation that comes from the soil is normal and does not pose a significant radiological hazard to the public. The natural radioactivity of soil in this area needs to be monitored periodically to prevent unnecessary radiation exposure to inhabitants.

ASSESSMENT OF RADIOLOGICAL HAZARD FOR VARIOUS FOOD COMMONLY USED IN REPUBLIC OF NORTH MACEDONIA

Consuming food containing radionuclides is particularly dangerous. If anyone ingests or inhales a radioactive particle, it continues to irradiate the body as long as it remains radioactive and stays in the body. However, studies on the radioactivity of consumable foods assume importance as it is necessary to estimate the ingestion dose to the public. Due to all this, the focus of this research was on determining the activity concentrations of 226Ra, 40K and 232Th. Forty-nine samples in three categories of vegetables, cereals (rice, wheat, corn), and milk, were collected from local markets (city of Skopje) in the Republic of North Macedonia and they were analyzed by using high-purity germanium (HPGe) detector to assess natural and artificial radioactivity. The average activity concentrations of 226Ra, 40K and 232Th of the tested samples were 2.85±1.15, 2.48±0.85, and 80.64±5.45 Bq kg-1, respectively. No artificial radionuclide was found in any of these samples. The average value of the radium equivalent activity in all samples was 12.56 Bq kg-1, which was less than the maximum permitted value of 370 Bq kg-1. The values ​​of the external hazard indices for vegetables, cereals and milk samples vary with an average value of 0.11, which is less than one in all samples indicating the non-harmfulness of the samples. The mean activity concentrations of 226Ra, 40K and 232Th (Bq kg-1) in the samples were used to calculate the absorbed dose rate whose mean value for all food samples was 6.16 Bq kg-1. It was determined that the measured values are within the globally accepted values, i.e., they are quite lower than the data in literature. These data would be useful to establish a baseline for natural radioactivity concentrations in food products consumed in the Republic of North Macedonia.