Natural Radionuclides In Soil Research Articles

Radiation protection for Gabes phosphate area residents: Assessing natural radioactivity in soil and potable water samples

Phosphate mining activities are recognized to be one of various industrial processes generating enhanced Naturally Occurring Radioactive Materials (NORM) by introducing natural radionuclides into the surrounding soils and water bodies, posing a risk to human health.This study was carried out to assess the level of natural radionuclides in soils and potable waters collected from the phosphate area of Gabes city, located in southeastern Tunisia, and to evaluate radiation protection measures by estimating radiological health hazard parameters. Gamma spectrometry system employing an HPGe detector was used in this study to assess 40K, 232Th and 226Ra activity concentration in soils. The average values were found to be 163.7, 14.5, and 7.7 Bq kg−1, respectively, which were lower than worldwide average values. The radiological hazard parameters assessed in this study were radium equivalent activity (Ra-eq), external hazard index (Hex), external gamma absorbed rate (GDR), external annual effective dose (Deff) and excess lifetime cancer risk (ELCR). The calculated average values of the above-mentioned parameters were of 41 Bq kg−1, 0.1, 20.2 nGy h−1, 24.8 μSv y−1 and 8.7 × 10−5 all of which were found to be below their permissible standards.For potable water samples, the activity concentrations of radium were analyzed using an HPGe detector and those of uranium were determined by alpha spectrometry. The average activity concentrations of uranium and radium isotopes in underground water samples were found to be higher than those obtained in tap water samples. For both types of water, the average values for all radionuclides were found to be below their respective reference limits.The annual ingestion effective doses were also estimated in this study. The estimated average values for infant and children for underground water samples were higher than the permissible limit of 100 μSv y−1 set by WHO. The 226Ra was the main contributor to the effective doses for different age categories, followed by 228Ra.

Assessment of Concentrations and Distributions of Natural Radionuclides in Soils of Abandoned Mine Sites of Jos South and Barkin Ladi in Plateau State Nigeria

Barkin Ladi and Jos South Local Government Area of Plateau State is situated in the central part of Northern Nigeria, on a rugged terrain of lowlands. It is the principal centre of tin and columbite mineralization, which forms the focal area of younger granites. The work was aimed at assessing the concentration and distribution of radionuclides in soils of abandoned tin mines and the soil’s physicochemical properties. The samples were collected in July, from five different locations in both Barkin Ladi and Jos South where mining activities were predominant. The samples were analyzed using a gamma-ray spectrometer. The result obtained reveals a range of the concentrations of 40K as 116.76 ± 0.21 to 250.15 ±0.,42 Bq/kg, 226Ra from 24.37 ± 0.31 to 90.45 ± 0.86 Bq/kg, and 232Th from 15.74 ± 0.71 to 88.43 ± 0.14 Bq/kg. The result of the physicochemical properties of the soil analyzed ranges from pH (3.12 to 6.81); organic carbon (0.01 to 1.62%); organic matter (0.22 to 3.01 %), cation exchange capacity (1.01 to 4,21Cmol/kg); clay (9.72 to 40.82 %); silt (8.32 to 40.32% and sand (32.42 to 75.38%) respectively. All the 40K results analyzed in all the sampling sites were lower than the recommended limits of 412Bq/kg, whereas most of the results of 226Ra and 232Th were above the 33Bq/kg and 45Bq/kg recommended safe limits. Exposure to elevated levels of naturally occurring radionuclides in soil can pose potential health risks to nearby populations. The physicochemical properties of the soil varied across the sampling sites. Most of the sampling sites are polluted with radionuclides and migrations of the radionuclides from the ex-mining sites to other parts of the environment were noticed from the studies conducted.

Activity concentration, transfer factor and radiological health risk assessment of natural radionuclides in soil and maize in oil producing areas in Akwa Ibom state, Nigeria

The activity concentration (AC) of 238U, 232Th, 40K of soil and maize in oil producing areas has been studied. Also studied are the transfer factor (TF) from soil to maize and the radiological health risk associated with consumption of maize. The equipment used was the Sodium Iodide-Thallium (NaI(TI)) detector. The mean activity concentration (AC) (Bqkg-1) of 238U, 232Th, 40K in soil are 12.77±0.25, 41.36±0.70 and 458.61±8.04 while that of maize are 14.36±0.27, 19.23±0.46 and 425.25±7.87 respectively. Transfer factor (TF) from soil to maize of 238U, 232Th and 40K are 1.14, 0.50 and 0.94 correspondingly. Other useful results obtained in this research include the Radium Equivalent (Raeq), Absorbed Dose Rate (ADR), Annual Effective Dose (AED) and Excess Lifetime Cancer Risk (ELCR) as 74.59 Bq/kg, 37.14 nGy/h, 0.05 mSv/y and 0.16 respectively. The average values of soil activity concentration from the oil producing areas are within world permissible limits given by UNSCEAR (2000) as 420 Bqkg-1 for 40K, 33 Bqkg-1 for 238U and 45 Bqkg-1 for 232Th. However, 238U and 232Th from maize activity concentration are far higher than world permissible limits of 0.02 Bqkg-1 and 0.003 Bqkg-1 respectively. The mean value of the radiological hazard indices was below the WMPV given as 370 Bq/kg for Raeq, 59 nGy/h for ADR, 1 mSv/y for AED and 0.29×10-3 for ELCR. This clearly shows that radiation doses exposed to Akwa Ibomites through the consumption of maize cultivated in this area poses very little to no effect to their health as only about 16 out of every 100,000 persons may likely have cancer fatality in their time.

Geochemical Distribution and Environmental Risks of Radionuclides in Soils and Sediments Runoff of a Uranium Mining Area in South China.

Uranium mining activities have contributed to the distribution and uptake of radionuclides, which have increased the active concentrations of natural radionuclides in environmental media, causing elevated human health risks. The present study aims to assess the spatial distribution characteristics of natural radionuclides in the surface soils and river sediments of the typical granite uranium mining area in South China, as well as investigate the geochemical features of natural radionuclides in the soil and sediments to understand their migration processes. The activity concentrations for 238U, 226Ra, 232Th, and 40K ranged from 17-3925 Bq/kg, 50-1180 Bq/kg, 29-459 Bq/kg, and 240-1890 Bq/kg, respectively. The open-pit mining areas and tailings pond locations exhibited the highest concentrations of activity for all these radionuclides. This distribution points to an elevated potential health risk due to radiological exposure in these specific areas. Additionally, the values of radium equivalent activity (Raeq) and annual gonadal dose equivalent (AGDE) in those areas were higher than the limits recommended by ICRP (2021). 238U and 226Ra have a significant correlation (0.724), and the cluster analysis was showing a statistically meaningful cluster below 5 indicated that they have similar behavior during parent rock weathering and watershed erosion, and the distribution of 232Th and 40K were influenced by the addition of rock types. The activity ratios of 226Ra/238U, 226Ra/232Th, 238U/40K, and 226Ra/40K variation indicated that 40K more mobile than 226Ra and 238U, U(VI) was reduced to U(IV) by organic matter in the downstream area and re-entered into the sediment during the sediment surface runoff in the small watershed of the uranium ore open-pit mining area. Therefore, it is necessary to further seal up and repair the tailings landfill area.

Quantification of radiological hazards associated with natural radionuclides in soil, granite and charnockite rocks at selected fields in Ekiti State, Nigeria

Assessment of activity levels of radionuclides that exist in soil, granite, and charnockite rock samples is very crucial because it exhibits an enhanced elemental concentration of uranium (U) and thorium (Th) contributing higher natural background activity than usual in the environment and it may cause health risk to human health through the external and internal exposure. This study determined the radioactivity levels of 238U, 232Th, and 40K radionuclides in soil, granite, and charnockite rock samples collected from selected fields in Ekiti State, Nigeria using Caesium iodide CsI(Tl) scintillation gamma spectrometer. It also evaluated indices of the radiological parameters consisting of radium equivalent activity (Raeq), absorbed dose rate (DR), annual effective dose equivalent (AEDE), internal hazard index (Hin), and excess lifetime cancer risk (ELCR). The calculated average activity concentrations of 238U, 232Th, and 40K are 30.40 ± 0.71 Bq kg−1, 3.31 ± 0.05 Bq kg−1, and 222.25 ± 14.72 Bq kg−1, respectively, which were lower than their respective world average values. Comparatively, potassium concentrations in these collected samples have a higher value than concentrations of uranium and thorium (40K > 238U > 232Th). All the evaluated values of the radiological parameters (except DR) of the appraised radionuclides were below the global permissible limits. The granite rocks, charnockite rocks, and soils from Ekiti State in Nigeria do not pose any hazardous risk to humans, but continued monitoring is necessary when these materials are used as building materials, which cause long-term radiation exposure.

Evaluation of radon hazards at the rural settlements of Uzbekistan.

The "passive" sorption detectors based on the activated charcoal together with scintillation spectrometry were utilized to measure radon flux density from the soil surface as well as volumetric activity of indoor radon at the dwellings of rural areas of Uzbekistan. Additionally, gamma dose rates as well as concentrations of natural radionuclides in soil and building materials samples were determined. Based on the values of natural radionuclides, common radiological indices have been calculated. It was found that varying greatly, 94% radon flux density values did not exceed 80mBq/(m2·s), while volumetric activities of radon were in the range of 35-564Bq/m3. The radium equivalent activity for studied soil and building materials samples were below the allowed limit of 370Bq/kg. Computed gamma dose rates were in the range of 55.50-73.89 ƞGyh-1 below the limit of 80 ƞGyh-1 and annual effective dose rate 0.068-0.091 mSvy-1, the average value of which was higher than the standard limit > 0.47 mSvy-1. The gamma representative index range was 0.89-1.19 with an average of 1.002 which was higher than the standard limit of 1.0. The range of activity utilization index was equal to 0.70-0.86 with an average value 0.77 which was lower than the recommended level ≤ 2.0. And lastly, excess lifetime cancer risk index values were from 1.9 × 10-4 to 2.5 × 10-4 and were lower than the recommended value 2.9 × 10-4 indicating low radiological risk. The results are consistent with the research conducted by other authors earlier, implying suitability of employing the method for the assessment of residential areas.

The theory and practice in application of methods for investigation on radionuclide speciation in soils

The paper provides a comparison of the various techniques for investigation of radionuclide speciation in soils based on fractionation of radionuclides bonded with different soil components. The dates on speciation of environmentally signifшcant technogenic and natural radionuclides in soils contaminated from testing of nuclear weapons, accidents or incidents at radiation dangerous objects, mining and mineral products processing are presented. The review looks at inf uence of natural and anthropogenic factors on the forms of the radionuclide compounds like the radionuclide and soil properties, type of radioactive fallout and the time elapsed af er fallout on soil. It has been demonstrated that experimental details of radionuclide speciation provide the basis for estimates and projections their mobility in soils, availability for plants and development of recommendations on reducing their penetration into food chains.

Activity Concentrations of Natural Radionuclides in Soil and Water Around Some Quarries and Potential Human Health Effects

Activity Concentrations of Natural Radionuclides in Soil and Water Around Some Quarries and Potential Human Health Effects

Natural Radionuclides in Soils of Natural-Technogenic Landscapes in the Impact Zone of Potassium Salt Mining

This study considers the contents of natural radionuclides (226Ra, 232Th, and 40K) in the soils of natural–technogenic landscapes in the Verkhnekamskoe potassium–magnesium salt deposit (Perm Krai, Russia). The purpose of the study is to assess the lateral activity distribution of natural radionuclides (226Ra, 232Th, and 40K) in the soils of natural–technogenic landscapes of the mining areas on the territory of the Berezniki–Solikamsk industrial hub. Seventy-five soil samples from depths of 0–0.4 m are examined. The specific activities of the natural radionuclides 226Ra, 232Th, and 40K in the soil samples are measured using gamma spectrometry. The average values of the activity concentrations of 226Ra, 232Th, and 40K are 11.78 Bq/kg, 8.11 Bq/kg, and 246.9 Bq/kg, respectively. A gamma survey is conducted using the MKS/SRP-08A search dosimeter–radiometer over a control point framework covering 50,000 hectares. The research shows that the migration of the studied natural radionuclides is limited to a radius of 10 km. The results of the gamma-radiation measurements in the study area fall within a range of 0.06–0.25 µSv/h, which does not exceed the permissible limits. According to the findings, there is an increase in the concentration of natural radionuclides in transit supra-floodplain terrace landscapes and accumulative floodplain landscapes in the area affected by potash mining.

Relationships between natural radionuclides activity concentration in soils of the State of Alagoas, Brazil and WRB/FAO soil classification, types of parental rocks and rainfall variability

Climate, soil type and geology that can influence the activity concentrations of natural radionuclides in soils. For this, 41 samples were collected in the first 25 cm of soil from the state of Alagoas, Northeast Brazil. This sample collection represents the mains soils classifications, parental rocks, and rainfall variability in this locality. The samples of soils were processed and analyzed by means of gamma-ray spectrometry for the 40K, 226Ra and 228Ra. The non-parametric Mann-Whitney U test was applied to perform the statistical inference on the differences in activity concentration for each soil class studied. There was a significant difference in the 40K activity distributions between the combination for most soil types. The results for 226Ra show no significant difference. However, Planosols differ significantly from Yellow Acrisols and Regosols for 228Ra. The strong relationship of the 40K concentration with the rock classes was shown. On the other hand, an association of the activity concentration of 226Ra and 228Ra with the rock type was not evidenced. There was a negative correlation between the 40K activity concentration and the rainfall index. 226/228Ra concentrations showed no correlation with the rainfall index.

Radionuclide contents in soil, sediments and food samples, and incidences of cancer in oil producing localities in Imo State south-east Nigeria

The communities in Ohaji-Egbema and Oguta Local Government Areas (LGAs) are surrounded by about 83 oil wells. Investigations indicated that crude wastes were not properly managed, and there were reported high number of cancer cases in the LGAs. Therefore, assessment of radionuclide contents in environmental and food samples, and incidences of cancer in the LGAs was carried out to determine any possible relationship between natural radionuclides in soil and sediment samples, and farm products, establish any possible relationship between reported cancer incidences and actual environment of the inhabitants, and develop models that could predict committed effective dose equivalents in yam, cassava and fish samples from radioactivity in soil and sediment samples. Soil, yam and cassava samples were collected from farmlands while sediment and fish samples were collected from rivers in the communities. The collected samples were prepared and taken to the laboratory for measurement. A well-calibrated lead-shielded 76 mm × 76 mm NaI (Tl) detector was deployed for the radiological investigation. It had a modest resolution of about 8% at 662 keV. Activity concentration of 214Bi (determined from its 1.760 MeV gamma-ray peak) was chosen to provide an estimate of 226Ra (238U) in the samples, while that of daughter radionuclide 208Tl (determined from its 2.614 MeV gamma-ray peak) was chosen as an indicator of 232Th. Potassium-40 was determined by measuring the 1.460 MeV gamma rays emitted during its decay. Results indicate that mean activity concentrations obtained from Ohaji-Egbema and Oguta are higher than those obtained from the control LGAs for 226Ra and 232Th which may be attributable to the geological variations of the study areas. The absorbed dose rates from Ohaji-Egbema and Oguta are slightly higher than world average value of 51 nGyh−1 while the committed effective dose equivalents from the study areas are less than world average value of 1.1 mSvy−1. The percentage contributions of natural radiation exposures to incidence of cancer in the study areas are less than 7% which implies that cancer incidences in the study areas may not be due to natural radioactivity levels. Hence, natural radioactivity levels may have been elevated in the communities of the oil producing localities but the concentrations are not yet frightening. In future environmental radioactivity studies, the developed models could be very useful.

Radiological assessment of natural radionuclides in soil from playgrounds in Southwestern Nigeria and evaluation of radiation dose

Radiological assessment of natural radionuclides in soil from playgrounds in Southwestern Nigeria and evaluation of radiation dose

INVESTIGATION OF ENVIRONMENTAL RADIOACTIVITY AT A DECOMMISSIONED URANIUM MINE IN SOUTHERN CHINA.

An environmental radioactivity survey was performed on a uranium mine that has been decommissioned for >10 y. According to the characteristics of this uranium mine, the relevant parameters, such as the surface-absorbed dose rate in air, the radon and radon progeny concentrations in the air, the radon exhalation rate from the soil surface and the concentrations of natural radionuclides in soil and surface water, were measured. The results show that the maximum annual effective doses of residents and employees in the uranium mine caused by radon and radon progenies inhalation were 1.48 and 1.74mSv, respectively, and the maximum annual effective doses of residents and employees caused by gamma-ray external radiation were 1.16 and 1.32mSv, respectively.

Radiogenic Heat Production Due to Natural Radionuclides in Soil and Sediments of Coastal Communities of Okrika Local Government Area of Rivers State, Nigeria

Thirty-six samples of soil and sediments were analyzed for radiogenic heat production due to three natural radionuclides from the Coastal communities of Okrika Local Government Area of Rivers state, Nigeria. 18 samples of soil samples were dug at a depth of 1 meter below the earth surface, and 18 samples of sediments were obtained from the bottom of the riverbed at a depth of 10-20 cm depth. Both samples are air-dried pulverized to fine fines and sealed in an air-tight container, left so several days to ensure secular equilibrium. The analysis was successfully carried out using NaI(Ti) Gamma-Ray Spectrometer to determine the radionuclides elementary composition of soil and sediment samples in terms of 40K, 238U and 232 Th respectively. The radiogenic heat production rate of soil ranged from 0.0058 µW/m3 to 0.0245 µW/m3 with a mean of 0.01255±0.02 µW/m3, while for sediment it varied from 0.0030 µW/m3 to 0.0131 µW/m3 a mean value of 0.01255±0.02 µW/m3. The result indicates that the coastal communities of Okrika had shown low radiogenic heat production rate. The soil and sediment samples from the coastal areas of Okrika shows low radiogenic heat production rate. The radiogenic heat production rate of soil and sediments was mostly from 238U in the order of 238U > 232Th > ⁴⁰K. Therefore, the radiogenic heat production rate determined for the coastal communities of Okrika as presented in this study, serves as baseline data and the basis for further investigations/research of its impact in the study area, and also creates a facet for hydrocarbon and geothermal energy resource investigation of the region.

A preliminary survey of natural radionuclides in soil and indoor radon in the town of Niš, Serbia

A preliminary survey of natural radionuclides in soil and indoor radon in the town of Niš, Serbia

Health risk profile of natural radionuclides in soils, sediments, tailings and rocks around mining sites in Nigeria

Health risk profile of natural radionuclides in soils, sediments, tailings and rocks around mining sites in Nigeria

Natural radionuclides in soil profiles and sediment cores from Jundiaí reservoir, state of Sao Paulo.

The activity concentration of natural radionuclides in soils and sediments is dependent on many factors, such as the rock parental material, pedogenic and weathering processes, physical and chemical properties of the environment, anthropogenic sources, among other aspects. There are few studies about the levels of natural radionuclides in reservoirs in both, international and national, literature. The objective of this paper was to evaluate the activity concentrations of 238U and 232Th by Instrumental Neutron Activation Analysis and 226Ra, 210Pb, 228Ra, 228Th and 40K by gamma spectrometry in two soil profiles and three sediment cores collected in the catchment area of Jundiai reservoir, located in the state of São Paulo, Brazil. Principal component analysis was applied to verify the correlation of the activity concentrations of the natural radionuclides with physical and chemical properties of soil and sediment samples. The mean activity concentrations of the radionuclides in the soil profiles 1 and 2 were, respectively: 238U – 37(1) and 32(1) Bq.kg-1; 232Th – 91(1) and 60(1) Bq.kg-1; 226Ra – 66(1) and 51(1) Bq.kg-1; 210Pb – 35(1) and 37(1) Bq.kg-1; 228Ra – 34(1) and 27(1) Bq.kg-1; 228Th – 78(1) and 58(1) Bq.kg-1; 40K – 96(2) and 171(7) Bq.kg-1. For the three sediment cores analyzed, the average activities concentrations of the radionuclides were, respectively: 238U – 64(0.5), 47(0.1) and 44(0.2) Bq.kg-1; 232Th – 122(2), 100(1) and 64(1) Bq.kg-1; 226Ra – 74(2), 71(1) and 45(1) Bq.kg-1; 210Pb – 70(3), 56(2) and 55(2) Bq.kg-1; 228Ra – 53(1), 41(1) and 33(1) Bq.kg-1; 228Th – 100(2), 92(1) and 63(2); 40K – 316(5), 237(1) and 136(2) Bq.kg-1.

Удельная активность радионуклидов и их взаимосвязь с валовым химическим составом почв

The total heavy metal content and activity concentration of natural radionuclides were obtained in native and anthropogenically transformed soil of the Rostov agglomeration (south of the Russia). The specific activity of natural radionuclides in soils of the has been comparable with indicators typical for chernozems of the Rostov region. Increased activity of 40K, 232Th is observed in the upper horizons, which is due to the origin of the radionuclides themselves and fertilization in the agrogenic period of soils, before the specified areas were included in the urban area. The correlation between activity concentration of radionuclide and total content of heavy metals were derived by Spearman's Rank-Order Correlation. The study was revealed that the activity concentration of thorium and radium doesn’t provide significant correlation with the total content of heavy metals. The group of buried horizons have shown a positive correlation with naturally occurring 40K in contrast with humus horizon (AU). The carbonates-accumulating group of horizons (BCA, [BCA]) have random correlation sign by each of metals. The most significant correlation was observed for the B horizons group.

Risk assessment of human exposure to radionuclides in soil of urban areas (public parks and open playgrounds) in Krusevac, Serbia

This study aims to obtain data on terrestrial radioactivity coming from naturally occurring (40K, 226Ra, 232Th, and 238U) and artificial (137Cs) radionuclides in surface soil (0-10 cm) of selected eighteen public-access urban areas in Krusevac city, Serbia, and to assess the corresponding health effects for citizens using those areas for recreational purposes. The specific activities of investigated radionuclides were analyzed using HPGe gamma-ray spectrometry. The mean specific activity of 40K, 226Ra, 232Th, 238U, and 137Cs was found to be 353, 39.8, 38.9, 41.0, and 5.9, respectively, in compliance with their values in other parts of Serbia and neighboring countries reported in similar researches. To evaluate the human health risk associated with radionuclides, conservative exposure assumptions and models recommended by the United States Environmental Protection Agency were employed taking into account three exposure routes: ingestion, inhalation of soil, and external irradiation. The absorbed gamma dose rate in the air due to natural radionuclides in soil was calculated. The calculated indices suggested that the radiation risk arising from natural and artificial radionuclides was not significant. The total excess lifetime cancer based on the 95 % upper confidence limit of the specific activities mean was calculated to be 5.89?10?6, lower than the tolerable risk for regulatory purposes (10?4). Among investigated radiation exposure pathways, external exposure was the most contributing one for the health risk. The results obtained for the city's parks and playgrounds suggested their safe use for recreational purposes from the radioecological point of view.

The analysis of natural radionuclides activity in the soil and vegetation cover in the South of the Tyumen Region

The paper deals with the study of the radiation state of the soil and herbaceous vegetation represented by perennial grasses (Poa pratensis, Calamagrostis epigejos, Rubus saxatilis, Carex acuta, Phleum pratense) in the south of the Tyumen Region. The content and distribution of natural radionuclides in soil and herbaceous vegetation was studied in the Nizhnetavdinsky District of the Tyumen Region at the site of an underground nuclear explosion. Sampling and laboratory tests were carried out according to generally accepted methods. Soil samples were taken at the epicenter of the explosion and at the cardinal directions. Layer-by-layer sampling allowed us to study the vertical distribution of radionuclides in the soil profile. Sampling of perennial grasses was carried out at the same sampling points. Radiation studies of soil and vegetation samples were carried out on the Progress-2000 spectrometric complex. The authors have revealed specific activity of natural radionuclides (K-40, Th-232 and Ra-226) in the profile of grey forest soil in the Nizhnetavdinsky District. They have calculated effective specific activity of radionuclides in the soil. The comparative analysis of the obtained results with the data on administrative areas in the south of the Tyumen Region showed that in the soil of the Nizhnetavdinsky District specific activity of natural radionuclides is higher than in the South region in general. The specific activity of natural radionuclides in perennial grasses of the Nizhnetavdinsky District was determined, and the coefficient of accumulation of radionuclides was calculated.