Radionuclides In Soil Samples Research Articles

Vertical distribution and radiological risk assessment of 137Cs and natural radionuclides in soil samples

The aims of this study were to investigate the vertical distributions of natural radionuclides 232Th, 226Ra and 40K as well as anthropogenic radionuclide 137Cs in soil samples and to analyze the correlation among the radioactivity of these radionuclides and the physiochemical characteristics of soil samples namely pH, grain size, carbonate content and organic matter. Risk assessment of the radiological hazard has also been estimated. Forty-four soil samples were collected from eleven locations in Qatar at four depth levels from 0 to 16 cm. The average concentrations of 232Th, 226Ra, 40K and 137Cs in the soil depth of 16 cm were 10, 17, 201 and 4 Bq/kg, respectively, which were within the reported world mean. The external absorbed gamma dose rate, the annual effective dose, the mean radium equivalent activity, the external hazard index and the lifetime cancer risk were 22 nGy/h, 0.027 mSv/y, 47 Bq/kg, 0.125 and 0.096 × 10−3, respectively. These values were far below the minimum recommended international values. The level of radioactivity concentrations in the soil was affected by the physiochemical characteristics of the soil. The positive correlation with highest R2 value was found among the radioactivity concentrations of 232Th and 40K and the soil clay content. Total organic carbon was also positively correlated for 226Ra and 137Cs activity concentrations, whereas, carbonate content was negatively correlated with the radioactivity concentrations of 232Th and 40K. As far as soil moisture content is concerned, the positive correlation with highest R2 value was obtained for 226Ra activity concentrations.

Assessment of radioactivity levels and its associated radiological hazards in soil of Babylon governorate middle of Iraq

The paper included a radial map of the study area for the first time in Iraq thirty-one samples of the soil in Babylon governorate were used for the purpose of measurement the radiation Pollution in the region. used γ-ray spectrometer NaI(TI) detector technique for the purpose of measurement the concentration of natural radionuclides of 238U, 232Th, 235U and 40K we found (397.230 ± 3.802 Bq/kg to 244.511 ± 2.983Bq/kg) for 40K (37.091 ± 1.005 Bq/kg to 1.879 ± 0.226 Bq/kg) for 238U,from (30.971 ± 0.814 Bq/kg to 0.192 ± 0.064 Bq/kg) for 232Th and (1.709 ± 0.280 Bq/kg to 0.086 ± 0.063)Bq/kg for 235U.The radiological hazards due to natural radionuclides content calculated such as gamma dos rate (AD), radium equivalent activity, annual effective does equivalent (AEDE) ranged between (0.4498 Bq/kg to 0.121 Bq/kg). The results obtained in this research were consistent with global results, the concentration of natural radionuclides in soil samples were within the worldwide value reported by UNSCEAR 2008.

Evaluation of Environmental Contamination and Estimated Radiation Exposure Dose Rates among Residents Immediately after Returning Home to Tomioka Town, Fukushima Prefecture.

On 1 April 2017, six years have passed since the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, and the Japanese government declared that some residents who lived in Tomioka Town, Fukushima Prefecture could return to their homes. We evaluated environmental contamination and radiation exposure dose rates due to artificial radionuclides in the livelihood zone of residents (living space such as housing sites), including a restricted area located within a 10-km radius from the FDNPS, immediately after residents had returned home in Tomioka town. In areas where the evacuation orders had been lifted, the median air dose rates were 0.20 μSv/h indoors and 0.26 μSv/h outdoors, and the radiation exposure dose rate was 1.6 mSv/y. By contrast, in the “difficult-to-return zone,” the median air dose rate was 2.3 μSv/h (20 mSv/y) outdoors. Moreover, the dose-forming artificial radionuclides (radiocesium) in the surface soil were 0.018 μSv/h (0.17 mSv/y) in the evacuation order-lifted areas and 0.73 μSv/h (6.4 mSv/y) in the difficult-to-return zone. These findings indicate that current concentrations of artificial radionuclides in soil samples have been decreasing in the evacuation order-lifted areas of Tomioka town; however, a significant external exposure risk still exists in the difficult-to-return zone. The case of Tomioka town is expected to be the first reconstruction model including the difficult-to-return zone.

Activity concentrations of radionuclides in soil samples along the coastal areas of Kerala, India and the assessment of radiation hazard indices

The present study was carried out along the coastal regions of Kerala, India, to evaluate the distribution of uranium, thorium and potassium concentrations in surface soil samples. A total of 92 soil samples were collected from 9 coastal districts, lying by the side of the Arabian Sea. The radium equivalent activities in the beach sands of Kollam district varies from 877 to 3715 Bq kg−1, which is higher than the reference limit of 370 Bq kg−1. Results show that the radiological parameters obtained for the beach sand from the districts of Thiruvananthapuram, Alapuzha, Eranakulam, Thrissur, Malappuram, Kozhikode, Kannur and Kasaragod are within the safe limits and hence these places can be considered as Normal Background Radiation Areas. Thus, when the high radioactive places are confined to a narrow belt in Kollam district, the other coastal areas of Kerala, especially northern and middle zones are within the safe limit with respect to radiological index.

Determination of natural radioactivity and radiological hazards in soil samples: Alhadba and Abuscabh agriculture projects in Libya

In this study, the radioactivity concentrations of the natural radioactive nuclides 238U, 232Th and 40K were measured in 26 surface soil samples of two areas of Libya. The soil samples were collected from two different agricultural lands in northwest Libya. The measurements of the activity concentration of selected radionuclides in soil samples were effectuated by gamma-ray spectrometry using hyper-pure germanium detector. The radiological hazard parameters: absorbed gamma dose rate, annual effective dose and the excess lifetime cancer risk were also determined to assess the radiation hazards caused by ionizing radiation emitted from the selected radionuclides on the population working and living in the selected regions. The levels of natural radioactivity of 238U, 232Th and 40K in the two areas were found to be below the internationally recommended level. On the other hand, these results indicated that there are no significant radiological impacts to the population because the values of radiological parameters are less than the international recommended limit. This indicates that the soils considered were safe for use in agriculture and do not pose any significant radiological hazards for human population.

An overview of radioactivity measurement studies in Pakistan.

In our environment, various naturally occurring radionuclides are present (both underground and overground) in several places, which results in lifelong human exposure. The radiation dose received by human beings from the radiation emitted by these naturally occurring radionuclides is approximately 87%. Exposure to radiation poses radiological health hazards. To assess the human health hazards from radiation, the concentration of these naturally occurring radionuclides are measured in soil (used for cultivation), building materials (soil, bricks, sand, marble, etc.), water and dietary items, worldwide. The available literature revealed that numerous studies related to the subject have been carried out in Pakistan. Most of these studies measured the radioactivity concentrations of primordial [uranium (238U), thorium (232Th), radium (226Ra) and potassium (40K)] and anthropogenic [cesium (137Cs)] radionuclide in soil samples (used for cultivation), fertilizers, building materials (i.e. bricks, rocks, sand, soil, marble, etc.), as well as water and dietary items, using a sodium iodide detector or high purity germanium. An effort was made in 2008 to compile these studies as a review article. However, since then, considerable studies have been undertaken and reported in the literature. Therefore, the main objective of the present article is to provide a countrywide baseline data on radionuclide levels, by overviewing and compiling the relevant studies carried out in Pakistan.

Mapping of the concentration of natural radionuclides in the Fundão Island, RJ, Brazil supported by geoprocessing and IDW interpolation

This work aims to determine the concentration activities of 226Ra, 228Ra and 40K radionuclides in soil samples from Fundao Island, Rio de Janeiro, using the gamma spectrometry technique with a hyper-pure germanium detector. The concentration found for 226Ra in the evaluated soil samples showed an average 42.21 Bq kg−1, a value within ranges found in national and international studies. For concentrations of 228Ra, the average found were around 131.23 Bq kg−1, being higher than the values found for soils in national and international studies. The 40K presented average values around 543.35 Bq kg−1, therefore within the range found for soils in both national and international literature. Amongst the analyzed samples and the determined elements, the 228Ra was the highest concentration detected. This result suggests that in these soils, the forming minerals are more concentrated in 232Th.

Activity concentration of NORM and 137Cs radionuclide in soil samples from the Andes Cordillera at latitude 33°56’ South

Activity concentrations of naturally occurring radioactive material (238U, 232Th, 40K) and 137Cs were determined in surface soil samples collected from four sites at latitude 33°56’ South and at an average altitude of 1650 masl in the Andes Cordillera, Chile. The handling of samples and the gamma spectroscopic analyses followed the recommended international protocols for this type of work. The presence of 137Cs due to fallout remains from atomic blasts produced in the Pacific atolls in the seventies was detected only in three sites analyzed in the current study. The activity concentration of this anthropogenic radionuclide showed significant uctuations ranging from below minimum detection activity to 21.32 Bq/kg. The ranges of activity concentrations of 238U, 232Th, 40K were found to be around 15-30, 22-30 and 411-611 Bq/kg respectively. The weighted mean activities concentrations of NORM radionuclides are within those reported from literature and were then used to calculate the radiological hazard indices. Values of external absorbed dose rate (D), the annual outdoor effective dose (AEDE), the radium equivalent activity (Raeq), and the external radiation hazard (Hex) index are within the accepted international ranges. These results point out that the radiation hazard due to NORM radionuclides found in soil samples from the sites studied in this work is not significant.

Geological influence on the activity concentration of terrestrial radionuclides 226Ra, 232Th and 40K in the Jos Plateau, Nigeria

ABSTRACTThe Jos Plateau has been reported to have elevated levels of natural background radiation. A few earlier studies have measured the levels of natural radioactivity for specific locations in the area. Our interest is to investigate how geology of the study area influences the activity concentrations of natural radionuclides. Thus, the activity concentrations of terrestrial radionuclides in soil samples collected across the geological formations of the Jos Plateau were determined by gamma spectrometry technique. The mean activity concentrations of 226Ra, 232Th and 40K were found to exceed their corresponding world reference values of 35, 40 and 400 Bq kg−1, respectively. Data were compared using statistical methods, analysis of variance (ANOVA) and post hoc tests. The results revealed in some instances significant influences of geological types on the activity concentrations in the area. The spatial distribution maps of activity concentrations of 226Ra, 232Th and 40K were geostatistically interpolated by ordinary Kriging method using ArcGIS software.

Measurement of activity concentration of primordial radionuclides in soil samples from Thirthahalli taluk and the assessment of resulting radiation dose

The activity concentration of primordial radionuclides 226Ra, 232Th, and 40K in soil samples of Thirthahalli taluk were measured systematically by using a low background HPGe detector coupled to 16 K MCA. The measured activity concentration of 226Ra lies between 5.1 ± 0.2 and 79.5 ± 1.7 Bq kg−1with an average activity of 25.99 Bq kg−1, 232Th ranges from 5.1 ± 0.3 to 95.3 ± 2.2 Bq kg−1with an average activity of 33.60 Bq kg−1and that of 40K varies from 18.3 ± 1.5 to 833.4 ± 17.5 Bq kg−1with an average activity of 175.52 Bq kg−1. Higher concentration of these radionuclides were found in the soil samples where the regional geology is granites. The consequential gamma dose and the corresponding radiation hazard was also estimated and is found to be within the permissible limits. The possible radiological impact on the public was also determined and these results are presented in this paper.

Measurement of radioactivity concentration in soil samples around phosphate rock storage facility in Richards Bay, South Africa

Mining, mineral processing and industrial activities have long been linked to increased levels of radioanuclides in soil in their vicinity. In this work, concentrations of naturally occurring radionuclides in soil samples collected around a rock phosphate storage facility in Richards Bay in South Africa were determined. A total of 90 soil samples were collected and analyzed for 238U and 232Th using neutron activation analysis and 226Ra and 4 K using a HPGe detector. The results revealed the average radioactivity concentrations of 238U, 232Th, 226Ra and 4 K in soil samples collected around the rock phosphate storage area were 28.26 ± 11.40, 29.64 ± 11.50, 32.18 ± 11.50 and 146.77 ± 63.30 Bq. kg−1, respectively, which are higher than the corresponding values of 22.26 ± 8.60, 23.09 ± 9.80, 26.52 ± 11.50 and 117.82 ± 10.04 Bq. kg−1 in soil samples from the control area about 2.0 km–4.5 km away from the rock phosphate storage facility. Furthermore, the all radiological hazard parameters (i.e annual effective dose equivalent, annual gonadal dose equivalent, the absorbed dose rate in air, the radium equivalent activity and the external Hazard Index) investigated in this study were below the maximum recommended safety limit. The observed 238U, 232Th, 226Ra and 4 K levels indicate contributions from anthropogenic activities with no significant health risks to humans or to the environment. Hence, in terms of terrestrial gamma radiation from soil, rock phosphate storage within this area does not pose any significant radiation hazard to the workers and dwellers.

Natural radioactivity level in soils around Kolar Gold Fields, Kolar district, Karnataka, India

The study on natural radioactivity level in the soil plays a significant role in health physics. The present study has been carried out with the aim of estimating activity concentration of radionuclides in soil samples collected at 30 places around Kolar Gold Fields, Kolar district using gamma ray spectrometry. Average values of activity concentration of 226Ra, 232Th and 40K in soil samples of the present study are 27.3 ± 1.8, 63.1 ± 2.5 and 818 ± 6 Bq kg−1, respectively. The average radium equivalent activity (Raeq), absorbed dose rate and annual effective dose have been calculated and compared with the referred safe values.

Determination of radioactivity concentrations in soil samples and dose assessment for Rize Province, Turkey

In this study, the activity concentrations of naturally occurring 40K, 238U, and 232Th radionuclides and of the artificial, Chernobyl accident-induced 137Cs radionuclide were measured in soil samples collected from Rize Province in the Black Sea region of Turkey.Rize is a city located in the Northeastern District of Turkey, which was significantly affected by the 1986 Chernobyl nuclear reactor accident in Ukraine, and the effects have continued to today. Tea is the main production plant of the region, and was contaminated by the artificial radioactivity. Therefore, measurements of residual 137Cs contamination in soil are critical for monitoring the potential impacts on human health.The activity concentrations of radionuclides in 24 soil samples from the study area were measured by means of gamma spectrometry with a Nal(TI) detector. The activity concentrations in soil samples varied in the range of 7.4–79.8 Bq kg−1 for 238U, 9.5–170.8 Bq kg−1 for 232Th, 35.7–913.8 Bq kg−1 for 40K, and 0.6–154.3 Bq kg−1 for 137Cs. The gamma absorbed dose rates in air were in the range of 10.7–156.4 nGy h−1, with an arithmetic mean of 56.9 nGy h−1, while the annual effective dose rates were determined to be in the range of 13.1–191.8 μSv y−1. The calculated values of external hazard index (Hex) for the soil samples in the study area were in the range of 0.12–0.94. The average value of radium equivalent activity was 125.0 Bq kg−1.The activity concentrations of radionuclides in soil samples were compared to the international values reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000) and previous studies on the area.

Radionuclides (40K, 232Th and 238U) and Heavy Metals (Cr, Ni, Cu, Zn, As and Pb) Distribution Assessment at Renggam Landfill, Simpang Renggam, Johor, Malaysia

The assessment of radioactivity levels and the distribution of heavy metals in soil samples at CEP Farm landfill, Renggam in Johor State was to determine the activity concentrations of naturally occurring radionuclides and heavy metal concentrations of this landfill. The background radiation was monitored to estimate the exposure level. The activity concentrations of radionuclides in soil samples were determined using HPGe gamma ray spectroscopy whereas the heavy metal concentration was measured using X-RF analysis. The mean exposure rate at the landfill site was 36.2±2.4 μR hr-1 and the annual effective dose rate at the landfill site was 3.19 ± 0.22 mSv yr-1. However, residential area has lower mean exposure dose rate of about 16.33±0.72 μR hr-1 and has an annual effective dose rate of 1.43±0.06 mSv yr-1 compared to landfill sites. The mean activity concentration of 40K, 238U and 232Th at landfill site were 239.95±15.89 Bq kg-1, 20.90±2.49 Bq kg-1 and 40.61±4.59 Bq kg-1, respectively. For heavy metal compositions, Cr, Ni and Cu have mean concentration of 232±10 ppm, 23±2 ppm, and 46±19 ppm, respectively. Whereas, Zn has concentration of 64±9 ppm and concentration of 12±1 ppm and 71±2 ppm was estimated for As and Pb respectively. The higher activity concentration of 40K down the slope through leaching process whereas the higher activity level of 238U content at the landfill site may be attributed to the soil disruption to local equilibrium.

Estimation of Natural Radioactivity and Radiation Exposure in Environmental Soil Samples of Golestan, Iran

Introduction: Considering the risk of radiation, the measurement of the natural radiation sources seems to be necessary. In this study, the concentrations of the natural radionuclides, namely 226Ra, 232Th, and 40K, were measured in the soil samples taken from different locations of Golestan, Iran. The measurement results can also be used as a baseline to evaluate the impact of non-nuclear activities and the routine releases of nuclear installations. Materials and Methods: A total of 42 soil samples were collected. The samples were sealed for at least three weeks to ensure the secular equilibrium between 226Ra and 232Th and their respective radioactive progenies. The activity concentrations of natural radionuclides in soil samples were measured using a shielded HPGe detector. Results: The average activity concentrations of 226Ra, 232Th, and 40K were 23, 31, and 453 Bq.kg-1, respectively. To assess the radiological hazards, the Ra equivalent activity as well as the external and internal hazard indices were estimated. Radium equivalent varied within the range of 58.4-142.6 Bq.kg-1 with a mean value of 102.4 Bq.kg-1. The estimated mean values of Hex and Hin (0.28 and 0.34, respectively) in the area under investigation were lower than unity as desirable. Therefore, it did not pose any health risks to the population of the area. Conclusion: The results of this study were compared with those of other studies carried out in other countries. As the findings of the present study indicated, the health-related risks causing by the naturally accruing radionuclides was very low in the investigated area.

Study of equilibrium status among uranium and thorium series radionuclides in soil samples from Visakhapatnam, India

Surface soil samples from coastal region of Visakhapatnam were analyzed for uranium series and thorium series radionuclides by high-resolution gamma-ray spectrometry. Isotopic ratios of 226Ra/238U and 224Ra/232Th were calculated to investigate the radioactive equilibrium status in the samples. 226Ra/238U and 224Ra/232Th ratios were found to vary from 0.80–1.40 to 0.94–1.40 with mean values of 1.05 and 0.99, respectively. Results showed a prevalent radioactive equilibrium for both uranium and thorium series radionuclides in the surface soil of the study area.

Activity concentration of anthropogenic radionuclides in soil samples

Activity concentration of anthropogenic radionuclides in soil samples

Uptake of uranium, thorium, radium and potassium by four kinds of dominant plants grown in uranium mill tailing soils from the southern part of China

The concentrations of radionuclides in soil from uranium mill tailings in South China were analyzed. The results showed that all radionuclides in soil samples exceeded the soil background value. Through the field investigation, four kinds of dominant plants were identified. It was found that the total quantity of radionuclides in the whole plant from high to low were pokeberry, Cibotium barometz, reed and garden sorrel. We also found that Cibotium barometz had the highest transfer factor (TF) for 238U, garden sorrel had the highest TF for 232Th and reed had the highest TF for 226Ra and 40K. Cibotium barometz had the highest bioconcentration factor (BF) for 238U, 232Th and 226Ra, and pokeberry had the highest BF for 40K. Pokeberry had the highest phytoremediation factor (PF) for 238U, 232Th, 226Ra and 40K. On the basis of the above conclusions, pokeberry could be a candidate for phytoremediation of radionuclide-contaminated soils.

Activity concentration of terrestrial and anthropogenic radionuclides (226Ra, 222Rn, 232Th, 40K, and 137Cs) in soil samples

Measurement of the activity concentrations of terrestrial and anthropogenic radionuclides in one hundred fifteen soil samples collected from various locations in Samsun city was taken using a gamma-ray spectrometer with a NaI (Tl) detector. The average activity concentrations of terrestrial radionuclides 226Ra, 232Th, and 40K were measured as 38.1 ± 1.4, 39.3 ± 0.8, and 375.3 ± 10.2 Bq kg−1, respectively. The average activity concentration of anthropogenic radionuclide 137Cs measured in some soil samples was found as 12.1 ± 0.7 Bq kg−1. Radon concentrations in soil and in air were estimated using results of the measurement of activity concentrations of 226Ra. The average concentrations of radon in soil and air were found as 32 kBq m−3 and 101 Bq m−3, respectively. The absorbed gamma dose rate in outdoor air due to terrestrial radionuclides in soil samples varied from 28 to 95 nGy h−1 with an average of 57 nGy h−1. The annual effective dose rates caused from external and inhalation exposure were estimated as 70 and 958 μSv y−1, respectively.

A century of oil and gas exploration in Albania: Assessment of Naturally Occurring Radioactive Materials (NORMs)

The Naturally Occurring Radioactive Materials (NORMs) that are potentially generated from oil and gas extractions in Albania have been disposed of without regulations for many decades, and therefore, an extensive survey in one of the most productive regions (Vlora-Elbasan) was performed. A total of 52 gamma ray spectrometry measurements of soil, oil-sand, sludge, produced water and crude oil samples were performed. We discovered that relatively low activity concentrations of 226Ra, 228Ra, 228Th and 40K, with concentrations of 23±2Bq/kg, 23±2Bq/kg, 24±3Bq/kg and 549±12Bq/kg, respectively, came from the oil-sands produced by the hydrocarbon extraction of the molasses formations. The mineralogical characterizations and the 228Ra/40K and 226Ra/40K ratios of these Neogene deposits confirmed the predictions of the geological and geodynamic models of a dismantling of the Mesozoic source rocks. The average activity concentrations (±standard deviations) of the radium isotopes (226Ra and 228Ra) and of the 228Th and 40K radionuclides in soil samples were 20±5Bq/kg, 25±10Bq/kg, 25±9Bq/kg and 326±83Bq/kg, respectively. Based on the measurements in this study, the future radiological assessments of other fields in the region should be strategically planned to focus on the oil-sands from the molasses sediments. Disequilibrium in the 228Ra decay segment was not observed in the soil, sludge or oil-sand samples within the standard uncertainties. After a detailed radiological characterization of the four primary oil fields, we concluded that the outdoor absorbed dose rate never exceeded the worldwide population weighted average absorbed dose rate in outdoor air from terrestrial gamma radiation.