Evaluation of radiological health risk caused by the use of fly ash in cement and concrete production and its storage.

As a result of firing pulverized coal in thermal power plants, enormous amounts of fly ash (FA) are produced as industrial waste. The release into the atmosphere and storage of this industrial waste remains one of the major environmental problems that threaten human health by contributing to air, water, and soil pollution. The recovery and reuse of FA in the construction industry is the only economic solution to the existing problem. In this study, the potential radiological risk caused by the usage of FA in concrete and cement production as a main component and its storage in landfill sites was evaluated for people and works by estimating radiological parameters (activity concentration and alpha index, annual effective doses, and the corresponding excess lifetime cancer risks) based on activity concentrations of terrestrial radionuclides in FA. Also, the radiological risk to the workers working in the FA landfill site was evaluated using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of terrestrial radionuclides in FA samples from the Tunçbilek lignite coal-fired thermal power plant at Kütahya province of Turkey were measured as 417, 156 and 454 Bq kg-1 for 226Ra, 232Th and 40K, respectively. When using up to 35% by mass of FA in cement and concrete, the average values of the radiological parameters revealed that they were within the recommended safety limits. However, code estimations showed that a regular worker in FA storage would be exposed to a total effective dose rate greater than 3 mSv y-1.

Assessment of NORMs (238U, 232Th, 40K) and radiation hazard indices in Beldih apatite mine region of Purulia district, West Bengal, India.

The radiation arising from naturally occurring radioactive materials (NORMs) is the foremost contributor to the collective dose received by the global population. The present study aims to measure the natural background radiation level and the associated gamma radiation dose in air in the Beldih apatite mine region of Purulia district, India. This study is primarily focused on the determination of 238U, 232Th and 40K activities in the sub-surface soil of the study area. The measurements were carried out using a High Purity Germanium (HPGe) detector-based gamma-ray spectrometer with a relative efficiency of 80%. To achieve uniformity in exposure estimations, radium equivalent activity has been calculated. Additionally, the internal hazard index, external hazard index, radioactivity level index and gamma dose rates have been evaluated to estimate the radiation hazard levels in the study area. The comparison of obtained concentrations and hazard indices with global data (UNSCEAR. (2008). Sources, effects and risks of ionizing radiation. United nations scientific committee on the effects of atomic radiation (report to the general assembly, with Annexes).) suggests that this region lies in a relatively high background radiation zone.

Investigation of natural and artificial radioactivity levels in travertines of the Cappadocia region in Turkey.

This study determined natural and artificial radionuclide concentrations to evaluate natural radioactivity and health risk levels of nine travertines in the Yaprakhisar and Balkayasi regions in Turkey. The samples coded B1-M, B2, B5, B7, B8, and B10 represent waste derived from the Yaprakhisar travertines, as well as samples T5-M, T12, and Z1 travertines derived from Balkayasi. The levels of natural and artificial radionuclide concentrations (232Th, 40K, and 137Cs) were measured using a high-purity germanium (HpGe) detector system. The travertine activity ranged from 2.09 to 12.07 Bq kg-1 for 232Th, 4.21 to 13.41 Bq kg-1 for 40K, and 0.42-3.26 Bq kg-1 for 137Cs. The results showed that the activity concentration values for 232Th, 40K, and 137Cs were coherent with the travertine analysis results in the UNSCEAR, 2000; 2008 publications. The values obtained were lower than the average values in the UNSEAR reports. The radiological hazard parameters calculated in this study were absorbed gamma dose rate (D), radium equivalent activity (Raeq), annual gonadal dose equivalent (AGDE), exposure dose (ER), total annual effective dose (AEDEtotal), excess lifetime cancer risk (ELCRtotal), gamma representative level (GRL), internal hazard index (Hin) and external hazard index (Hex).

Assessment of natural radioactivity in the Higher and Tethys Himalayan Rocks along Manali-Leh Highway, India.

The Higher and Tethys Himalayan region of NW-Himalaya is less explored from the natural radioactivity mapping assessment, though geologically and tectonically, this region is still active. The concentration of primordial radionuclides (226Ra, 232Th, and 40 K) in rock samples of the Manali-Leh Highway region of the Himalayas is determined in the present study using the HPGe detector. The radiological hazard parameters are also estimated in terms of radium equivalent activity (Raeq), annual effective dose (Ein and Eout), hazard indices (Hin, Hex, Hα, and Hγ), and gamma absorbed dose rate. SEM-EDS analysis was used to understand the mineralogical composition of the rocks. The activity concentration of 226Ra, 232Th, and 40 K radionuclides varies from 1.4 ± 0.9 to 25.3 ± 1.2, 0.7 ± 0.5 to 59.6 ± 1.6, and BDL (below detection limit) to 830.3 ± 45.7 Bq kg-1, with an average value of 13.0 ± 1.0, 21.7 ± 1.0, and 243.7 ± 25.2 Bq kg-1, respectively. The average of Raeq in the study region lies within the safe limit of 370 Bq kg-1. The hazard indices have values < 1, indicating no radiological hazards to the population from the rocks. The annual effective dose also has values less than the global average value. This study revealed that the rocks of the Higher Himalayan region have a higher concentration of natural radioactivity, while the Tethys Himalayan rocks have lower concentrations of 226Ra, 232Th, and 40 K radionuclides. The origin of rocks from different lithologies may be the reason for the natural radioactivity variation. The average concentrations of primordial radionuclides in the region are within the world average indicating that the rocks of the region are safe to be used for different purposes.

Natural radionuclides and radiological risk assessment in the stream and river sediments of a high background natural radiation area Kanyakumari, India.

The Kanyakumari coast is known to be a high background natural radiation area due to the placer deposits of heavy minerals such as ilmenite, monazite, and rutile. The Kanyakumari river sediments that could be the source of the elevated amounts of natural radionuclides in the coastal sands have been studied in this paper. The activity concentrations of primordial radionuclides 226Ra, 232Th, and 40K were determined using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 75 Bq kg-1, 565 Bq kg-1, and 360 Bq kg-1, respectively. The mean absorbed dose rate was 395 nGy h-1. Radiological hazard parameters were studied and compared with the world average values. The contribution of 232Th to the total dose rate was found to be higher than that of the two other radionuclides. The high mean ratio of 232Th/226Ra suggested an enrichment of 232Th and the occurrence of 226Ra leaching due to an oxidizing environment. Principal component analysis (PCA) was carried out for the radionuclides in order to discriminate the source of the sediments. This study provides new insights into the distribution of natural radionuclides in sediments of rivers and streams.

Natural radionuclide profiles and radiological risks in soils and rocks of the Koytash-Ugam Range, Uzbekistan.

This investigation quantifies the activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) in the soils and certain rocks of the Koytash-Ugam Range, Uzbekistan, and assesses their radiological risks. Gamma-spectrometric analysis of soil and rock samples revealed activity concentrations ranging from 456.2 ± 56.0 to 813.9 ± 76.0 Bq kg-1 for 40K, 18.2 ± 6.3 to 70.0 ± 12.0 Bq kg-1 for 226Ra, and 30.1 ± 2.9 to 57.9 ± 10 Bq kg-1 for 232Th. This data indicates a heterogeneous distribution of radionuclides, informing radiation safety and health risk assessments on a global scale. The calculation of radiological hazard indices, including the alpha-index (ranging from 0.09 to 0.35), gamma-index (ranging from 0.40 to 0.73), and both internal (ranging from 0.40 to 0.54) and external (ranging from 0.36 to 0.54) hazard indices, was undertaken to ascertain potential health risks. The radium equivalent activity ranged from 108.4 to 199.3 Bq kg-1, and the absorbed dose rates were 51.0-93.3 nGy h-1 indoors and 96.6-178.2 nGy h-1 outdoors. These metrics underlie the estimated annual effective dose of 536.5-988.5 × 10-3 mSv y-1, highlighting the variability in radiation exposure. Additionally, the potential lifetime cancer risk was projected at 1770.4 to 3262.0 per million, with an annual gonadal dose equivalent of 361.9 to 655.5 µSv y-1, reflecting natural background radiation influence. The results underscore the importance of safe material use in construction and the necessity for routine natural radioactivity monitoring. Radon flux density (RFD) values within acceptable construction limits (26-176 mBq m-2 s-1) suggest the area's suitability for development, considering recommended safety guidelines. This study not only aids local environmental and public health frameworks but also enriches the international knowledge base, facilitating comparative studies for the advancement of global radiation protection standards. Through a detailed examination of radionuclide distribution in an under-researched area, our research highlights the critical need for integrated international approaches to natural radiological hazard assessment.

Assessing radioactivity levels in agricultural soil: a comparative study of traditional vs. modern fertilization techniques in Tunisian oases.

To establish a radiological national reference for agricultural soil across Tunisian oases and assess the risk to human health associated with date consumption, with a focus on comparing the impact of traditional and modern fertilization, radiological parameters and activity levels of 226Ra, 232Th, and 4°K were determined for 27 oases. These oases were located in three southern Tunisian governorates. The activity concentration of 226Ra, 232Th, and 4°K was measured using a 3 × 3 inch NaI(Tl) scintillation detector, which was found to be 21.82 ± 1.0 Bq kg - 1 , 26.51 ± 1.1 Bq kg - 1 , and 559.21 ± 23.0 Bq kg - 1 , respectively, for traditional oases and 26.56 ± 1.2 Bq kg - 1 , 24.45 ± 1.1 Bq kg - 1 , and 661.28 ± 26.3 Bq kg - 1 , respectively, for modern oases. In addition, ambient dose equivalent rate was measured during sampling using a multipurpose hand-held radiation CsI(Tl) detector, which was found to be 0.075 µSv/h in traditional oases and 0.078 µSv/h in modern oases. The resulting radiological parameters and activity concentrations were then compared to results from neighboring countries and the average soil activity worldwide.

Distribution of radionuclides in the soils and assessment of radiation hazards in AL Najaf, Iraq: A cross sectional analysis.

OBJECTIVE: To evaluate radioactivity levels in soil samples and their physical impact on the population. METHODS: The experimental radiation study was conducted by researchers belonging to the Kufa University in Al- Najaf, Iraq, in August 2020, and comprised soil samples from Al-Rahma area. Sodium iodide detector activated with a trace amount of Thallium with crystal dimensions 3" x 3" was used to calculate the concentration of Radium, Thorium and Potassium. RESULTS: Among the 15 samples collected, the average ± standard deviation (SD) concentration for Radium, Thorium and Potassium was 0.1776±0.12, 0.726±0.435 and 1.9128±1.105%, respectively. The reported value of excess lifetime cancer risk was 1.2819×10-3. CONCLUSIONS: The area studied was found to be a safe area and did not pose a health threat to the locals.

Calculation of radiological risks for selected soil samples from the north of Kufa district in Najaf, Iraq.

OBJECTIVE: To evaluate radioactivity levels in soil samples and their physical impact on the population. METHODS: The experimental radiation study was conducted in northern Kufa, Al Najaf Governorate, Iraq, in March 2020 by researchers from the Kufa University, Iraq and comprised soil samples. A gamma spectrometer equipped with a sodium iodide detector activated with a trace amount of thallium was used to calculate the concentration of radium, thorium and potassium. Data was analysed using SPSS 20. RESULTS: There were 30 samples. The average concentration of Radium, Thorium and Potassium was (0.824± 0.392)ppm, (1.536± 0.645)ppm and( 0.597± 0.195)%, respectively, and the radiation hazards were lower than the permissible levels. The reported value of excess lifetime cancer risk was (1.2819 ±0.156)×10-3, and the annual gonadal equivalent dose (AGED) was 116.496± 41.255 (mSv. y-1), which was lower than the recommended limit. There was a positive, strong and significant relationship of radium with all the variables (p<0.05) studied except with potassium (p>0.05). Thorium was positively and significantly associated with all the variables (p<0.05). CONCLUSIONS: The study area was found to be safe and there was no relationship between the radiation levels of the studied nuclides and the risk of cancer.

Geological control of terrestrial background radiation in Garhwal Himalaya, India.

Activity concentrations of 226Ra, 232Th, and 40K were measured in soil samples from several areas of Garhwal Himalaya, Northern India, by gamma-ray spectrometry. In this region, which extends around the Himalayan Main Central Thrust, a tectonic line that separates several geological provinces, background levels of natural terrestrial radiation were assessed. The maximum levels of radium, 285 Bq/kg and 136 Bq/kg, respectively, were found in the Budhakedar and Uttarkashi regions, exceeding the world average value of 35 Bq/kg. The mean radiation levels were found to be different between the areas, which reflects the geological diversity in the region. The overall absorbed dose rate owing to radionuclide presence in the Uttarkashi area ranged from 79 to 188 nGyh-1, with an average of 118 nGyh-1. That is more than UNSCEAR's world-populated weighted average value of 59 nGyh-1. The present investigation indicated that the absorbed dose rates are greater in Uttarkashi and Budhakedar than in other places. The multiple comparison analysis between geology and absorbed dose rate shows that the geology of Uttarkashi and Budhakedar are statistically similar. According to several hazard indices, terrestrial background radiation is not of radiological concern in the investigated region.

Distribution dynamics and descriptive statistical analysis of radionuclides in the farmland soils near mining areas in Southwestern Nigeria.

Human exposure to ionizing radiation in the environment is mainly due to naturally occurring radionuclides in the soils, building materials and rocks, but the level may vary depending on the anthropogenic activities prevalent in each location. Presently, in Nigeria, there are concerns due to environmental health implications of all sorts of mineral mining and processing spreading across the southwestern states of the country. This work determines the activity concentrations of naturally occurring radionuclide materials (NORMs) in the farmland soil with the aim of evaluating the radiation hazards. A total of 200 composite soil samples were taken from five states in the southwest of Nigeria, close to active mining sites at the root (0.2 m) and at deep planting zones (0.5 m) for analysis by gamma-ray spectrometry using NaI(Tl) detector. The activity concentrations of natural radionuclides in the composite soil samples were determined to vary in the order of 40 K > 232Th > 226Ra/238U for all locations. In contrast to the other locations, Olode and Igbokoda had average radium equivalent activities (Raeq) to be 1.6 and 1.8 times, respectively, higher than the reference limit of 370 Bqkg-1. The estimated excess life cancer risk values were lower than the 0.29 × 10-3 global average value for soil by United Nations on Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and International Commission on Radiological Protection (ICRP). Negative and low skewness values of 0.61 and 1.20 were obtained for 40 K in Itagunmodi, and also 0.47 and 0.66 for 232Th were obtained in Sagamu. The kurtosis analysis of the activity concentrations was low and negative for soil at Itagunmodi for 40 K and 226Ra/238U; Olode for 40 K and 232Th; and Igbokoda for 226Ra/238U and 232Th where mining activities are commonly practiced. The variation in the results has been attributed to different agriculture practices and artisanal mining operations in each location.

Radiological and environmental hazards of granitic rocks in Wadi Faliq El Sahl and El Waar area, North Eastern Desert, Egypt.

Chronologically, the main exposures in the study area include; tonalite, granodiorite, adamellite, Hammamat Sediments, monzogranite, syenogranite, rapakivi syenogranite, alkali feldspar granite and dykes. This work aims to determine the suitability of the granitic rocks for using as ornamental stones through detecting their radiological and ecological impacts. The studied samples were measured radiometrically by using Na-I detector for determination of 226Ra, 232Th and 40K concentrations. External hazard indices (Hex) in some samples are more than unity, also, the (Raeq) are higher than the exemption limits (370 Bq.kg-1) exceeds the upper limit of exposure. The hierarchical cluster analysis (HCA) was applied to investigate the correlation between the radionuclides and the corresponding radiological hazard variables. Based on the statistical analysis, 232Th and 226Ra mainly contribute to the radioactive risk of the studied rocks. Regarding ecological indices, 42.1% of younger granite samples have Pollution load index values greater than 1, indicating deterioration, while the majority of older granite samples are lower than 1 suggesting perfection samples. Where, some sample from the older granitoids and younger granites have many radiological and ecological parameters greater than the recommended international limits, so, these samples should not be used in construction for safety reasons.

Evaluation of natural radioactivity in soils of Konya (Turkey) and estimation of radiological health hazards.

Surface soil samples were collected from Konya, Turkey and natural activity concentrations were determined using the ɤ-ray spectroscopy system with HPGe detector. The activity concentrations of 226Ra, 232Th and 40K were found to vary from 14.07 ± 0.71 Bq kg-1 dw to 67.27 ± 1.62 Bq kg-1 dw, 10.19 ± 2.60 Bq kg-1 dw to 46.09 ± 0.76 Bq kg-1 dw and 107.87 ± 13.32 Bq kg-1 dw to 605.95 ± 11.34 Bq kg-1 dry weight (dw), respectively. The radiological hazard parameters such as Raeq, D, AEDE, ELCR, AGDE, Hex, Hin, and Iɤ evaluated the radiological risk for the public and environment. The mean values of D, AEDE and ELCR are lower than the world average value of 57 nGy h-1, 70 µSv y-1, 0.29 × 10-3 respectively. The activity concentration distribution maps of 226Ra, 232Th and 40K and the radiological maps of the radiological hazard parameters were plotted using the Surfer programme. Cluster analysis was carried out to indicate the similarity between the variables.

Radiological health assessment of infant milk in Erbil Governorate, Iraq.

In this research, the radioactivity caused by natural radionuclides (40 K, 232Th, and 226Ra) was evaluated in infant milk consumed in Erbil, Iraq. The measurements were performed using an HPGe gamma-ray spectrometer. The variation of activity concentrations in milk samples was (99.56-256.9 Bq kg-1) for 40 K, (BDL-0.53 Bq kg-1) for 232Th, and (0.27-5.59 Bq kg-1) for 226Ra, as determined by the results. The radiological parameters of Eing, Dorg, and ELCR were calculated and compared to international standards. The correlation between computed radiological hazard parameters and natural radionuclides was analyzed statistically using Pearson's correlation. Overall, the results indicate that infant milk consumption in Erbil is radiologically safe and that consumers of these brands of milk are unlikely to be directly exposed to radiological health risks.

Vertical distributions of radionuclides along the tourist-attractive Marayon Tong Hill in the Bandarban district of Bangladesh.

This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.15 ± 3.76 Bqkg-1, 19.69 ± 2.15 Bqkg-1, and 347.82 ± 24.50 Bqkg-1, respectively, where in most cases, 232Th exceeded the world average value of 30 Bqkg-1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of 137Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of 232Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024.

Evaluation of radioactivity in soil and rock samples from an undiscovered sea beach in the southeastern coastline of Bangladesh and associated health risk.

This study marks the first-ever assessment of radiological hazards linked to the sands and rocks of Patuartek Sea Beach, situated along one of the world's longest sea beaches in Cox' Bazar of Bangladesh. Through the utilization of an HPGe detector, a comprehensive analysis of the activity concentrations of 226Ra, 232Th, and 40 K was conducted, and their activity ranged from 7 to 23 Bq/kg, 9-58 Bq/kg, and 172-340 Bq/kg, respectively, in soils, and 19-24 Bq/kg, 27-39 Bq/kg, and 340-410 Bq/kg, respectively, in rocks. Some sand samples exhibited elevated levels of 232Th, while the rock samples displayed higher levels of 40 K compared to the global average. The radiological hazard parameters were assessed, and no values surpassed the recommended limits set by several international organizations. Hence, the sands and rocks of Patuartek sea beach pose no significant radiological risk to the residents or tourists. The findings of this study provide crucial insights for the development of a radiological baseline map in the country, which is important due to the commissioning of the country's first nuclear power plant Rooppur Nuclear Power Plant. The data may also stimulate interest in the rare-earth minerals present in the area, which is important for the electronics industry, thorium-based nuclear fuel cycles.

Evaluation of soil radioactivity in the areas of underground nuclear explosions at the Pomuk gas field site in Uzbekistan.

This study investigates soil radioactivity at the Pomuk gas field in Uzbekistan, a region with history of underground nuclear activity. Using a NaI (Tl) scintillation gamma spectrometer, soil samples were analyzed for concentrations of 232Th, 226Ra, 40K, and 137Cs. Concentrations were found to be in the range of 19.0-31.0 Bq/kg for 232Th, 12.0-32.0 Bq/kg for 226Ra, 450.0-634.0 Bq/kg for 40K, and 2.4-11.0 Bq/kg for 137Cs. Surface radon flux density was measured using a coal sorbent-based passive method, with values ranging from 26.1 to 79.0 mBq/m2s. Mean activity values for radium equivalent (Raeq) and gamma representative level index (Iγ) were calculated to be 75.2-96.5 Bq/kg and 0.3-0.4 Bq/kg, respectively. The absorbed airborne gamma dose rates (GDR) varied between 41.0 and 52.0 nGy/h, while annual effective dose rates (AEDR) were 0.3-0.4 µSv/year. The radiological risk assessment indicates the area is within safe limits for the population and environment, providing a foundation for future radiological monitoring programs.

Radiogeochemistry, mineralogy, lithology, radiogenic heat production, and health implication using airborne radiometric data of Ilesha and its surroundings.

The current study analyzed and interpreted airborne radiometric data from Ilesha's basement complex rock and its surroundings. At the surface, the concentrations of the most frequent primordial radionuclides notably K, elemental concentration of uranium eU, and elemental concentration of thorium eTh were measured. The weighted mean elemental and activity concentrations were 0.85%, 2.75 ppm, 10.22 ppm, and 267.54 Bq kg-1, 34.41 Bq kg-1, 41.51 Bq kg-1 for 40 K, 238U, and 232Th, respectively. The low concentration of 40 K was certainly due to the effects of weathering, kaolinization of granites, and pedogenesis activities. The abundance of uranium was ascribed to the availability of uranium minerals such as allanite, apatite, and sphene with accessories minerals, while that of thorium was due to minerals such as cheralite, thorite, uranothorite, thorianite, and uranothorianite with accessories minerals. The RPHR weighted mean 1.48 µWm-3 compared to the earth's crust mean between 0.8 and1.2 µWm-3 was higher due to significant presence of gneiss rocks in all the studied profiles. Radiological hazard, in particular, dose rates, external hazard index, internal hazard index, radium equivalent, annual gonadal dose, effective dose dispensed to various organs of the body were computed to determine the deleterious effects of rocks in the area. The weighted means of annual gonadal dose of 363.98 µSv y-1 and outdoor 0.91 × 10×3 and indoor 1.65 × 10-3 excessive life cancer risks were more than the global average 300 µSv y-1, 0.29 × 10-3 and 1.16 × 10-3. As a result, proper surveillance is required in the area in order to prevent epidemics occurrence in future.

Radioactivity amounts, annual effective dose rate, and lifetime cancer risk estimation of some vegetable and fruit samples cultivated in Kahramanmaras, Turkey.

In this research, examples of the fruits and vegetables cultivated in Kahramanmaras, 238U, 232Th, and 40K levels, were detected, and in the case of consumption of these vegetables and fruits, for several age categories (adults, children (10 years old), and infants), annually effective dose rates and lifetime cancer risks were calculated. In fruit samples, concentrations of 238U, 232Th, and 40K ranged from under detection limit (UDL) to 15.29 ± 1.14 Bq/kg, 0.30 ± 0.01 to 13.23 ± 1.60 Bq/kg, and 5.82 ± 0.21 to 179.82 ± 1.34 Bq/kg, respectively. The mean concentrations of 238U, 232Th, and 40K in fruit samples were 5.31 ± 0.44 Bq/kg, 2.72 ± 0.26 Bq/kg, and 56.84 ± 0.57 Bq/kg, respectively. In vegetable samples, concentrations of 238U, 232Th, and 40K ranged from 0.48 ± 0.04 to 11.77 ± 0.95 Bq/kg, 0.55 ± 0.04 to 4.57 ± 0.44 Bq/kg, and 9.32 ± 0.43 to 52.44 ± 0.52 Bq/kg, respectively. The mean concentrations of 238U, 232Th, and 40K in the vegetable samples were 6.58 ± 0.65 Bq/kg, 2.72 ± 0.27 Bq/kg, and 27.09 ± 0.27 Bq/kg, respectively. The mean annual effective dose rates for adults, children (10 years old), and infants in fruit samples were 0.184 ± 0.001 mSv/y, 0.288 ± 0.002 mSv/y, and 0.304 ± 0.003 mSv/y, respectively. The average lifetime cancer risks for adults, children (10 years old), and infants in fruit samples were 0.647 ± 0.006 × 10-4, 1.011 ± 0.010 × 10-4, and 1.067 ± 0.010 × 10-4, respectively. The mean annual effective dose rates for adults, children (10 years old), and infants in the vegetable samples were 0.118 ± 0.001 mSv/y, 0.128 ± 0.001 mSv/y, and 0.086 ± 0.001 mSv/y, respectively. The mean lifetime cancer risks for adults, children (10 years old), and infants in vegetable samples were 0.416 ± 0.004 × 10-4, 0.449 ± 0.004 × 10-4, and 0.304 ± 0.003 × 10-4, respectively.

Radiological risk assessment from the Gamma spectrometry of soil samples in the vicinity of a research centre in Nilore, Pakistan.

Measurements of radionuclides' activities in air, water, and soil give clues about the anthropogenic activities in the region, and imperative to assess the overall radiological risk for individuals. Such an investigation was carried out to characterize the soil activities in the region hosting a research center, and to calculate the associated elements of radiological risk in terms of radiation doses and hazard indices. The soil samples were collected within the radius of 10 km in local area, Nilore, and analysed for activity using a high-purity germanium (HPGe) gamma spectrometric system. In all samples, only the basic nuclides, contributing to terrestrial activity, i.e., 40 K, 232Th, 226Ra, and 137Cs, were observed within the detectable limits of activity. The distribution of the data set and the correlation between the measured activities were studied with the use of the principal component analysis (PCA). The measured average specific activities of 226Ra, 232Th, 40 K, and 137Cs were 40.65 ± 9.84 Bq/kg, 59.31 ± 16.53 Bq/kg, 528.24 ± 131.18 Bq/kg, and 5.16 ± 4.56 Bq/kg respectively. The corresponding dose rate in air was found to be 76.63 ± 18.39 nGy/h, which is slightly higher than the world median value of 51 nGy/h calculated from concentration of terrestrial radionuclides in soil but falls within the world average value range of outdoor external exposure of 18-93 nGy/h obtained through direct measurement, and therefore not harmful for the living species. The standard hazard indices for all soil samples such as radium equivalent activity ([Formula: see text]), external hazard index (Hex), and internal hazard index (Hin) were also found within safe limits for the soil to be used as construction of building material. This investigation led to conclusion that the soil activities are consistent with the usual background level of terrestrial activities, and their associated dose rates are well within the safe limits for public.