226Ra Concentrations Research Articles

Assessing Radiological Risks of Natural Radionuclides on Sustainable Campus Environment

Soil samples were collected from a college campus in Taiwan to measure the levels of radionuclides, contributing to the sustainable management of campus environments. A high-resolution HPGe gamma spectrometry system was utilized to measure the activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) and artificial radionuclide (137Cs). The activity concentrations of 137Cs were not detected in the campus soils, suggesting that artificial radionuclides did not contaminate the soil, supporting sustainable soil quality. However, the average concentrations of 232Th and 40K with mean values of 53.4 ± 5.1 and 504.5 ± 75.4 Bq/kg dw were higher than the global soil average of 45 and 420 Bq/kg dw, respectively. Meanwhile, the average concentration of 226Ra with a mean value of 30.1 ± 3.0 Bq/kg dw was similar to the global soil average of 32 Bq/kg. The average outdoor absorbed gamma dose rate (Dex) and annual effective doses (AEDex), with a mean of 67.2 nGy/h and 82.4 μSv/y, were found to be higher than the average world levels of 57 nGy/h and 70 μSv/y, respectively. Despite these findings, the radium equivalent activity Raeq and external hazard index Hex, with average values of 145.2 Bq/kg and 0.39, respectively, were below the recommended limit values of 370 Bq/kg and 1.0, respectively. This study provides useful information on the background radioactivity of the study campus, which is crucial for developing sustainable strategies to ensure a safe and healthy environment, indicating that there are no radiological hazards in the soil.

Chronic Radium-226 toxicity to and oxidative stress in the aquatic invertebrate Chironomus dilutus

Abstract The mining industry, including uranium mining and milling, is of high importance in Canada. It is, however, important to consider that ore processing can result in the creation of by-products that contain radionuclides such as radium-226 (226Ra). Even with the strict discharge regulations in place, there is limited evidence to suggest that the current Canadian regulatory thresholds for 226Ra are protective for aquatic life. This concern underscores the importance of generating toxicity data for 226Ra, as no federal Canadian water quality guidelines for 226Ra currently exist to safeguard aquatic ecosystems. The potential ecological risks of 226Ra are significant due to its high mobility under typical environmental conditions, long half-life (t1/2 ~ 1,600 years), bioaccumulative properties, and similarity to calcium (Ca2+). Considering this, the primary objective of this research was to gather data on the toxicity of 226Ra to the aquatic invertebrate Chironomus dilutus. For this purpose, a partial life cycle experiment was conducted, with larval growth, survival and pupation, and emergence and sex ratio of emerged adults, as the experimental endpoints. In addition, an assessment of oxidative stress as a potential cause of toxicity was performed. These experiments revealed that elevated activity concentrations of 226Ra (25.5 Bq/L) can significantly impact the growth of C. dilutus. However, none of the other nonlethal endpoints were significantly affected by 226Ra exposure, and there was no evidence of oxidative stress in exposed C. dilutus. Finally, 226Ra was shown to adsorb onto the silica sand used as a substrate for all experiments and desorbed following acid extraction.

ASSESSMENT OF NATURAL RADIOACTIVITY OF SALT SAMPLES WITH REDUCED SODIUM CONTENT

Poles are the leaders in Europe in terms of the amount of salt consumed per day. Table salt is themost frequently used spice and is essential for the proper functioning of the body. However, itsexcessive consumption may have adverse effects on human health. The Word Health Organization(WHO) informs that the leading cause of premature deaths in the European region of WHO is thecardiovascular disease. This is why medicine is increasingly recommending the use of low-sodiumsalt, which contains a reduced content of sodium and an increased content of potassium becauseit is essential for the proper functioning of the brain, cells and for proper work of muscles. Thereis no information in the literature on the concentration of natural radioactive isotopes presentin sodium-reduced salts used as a substitute for table salt. Therefore the aim of this study wasestablishing the concentration of natural radioactive isotopes in salt samples with low sodiumcontent available in retail sale on the Polish market and widely used in Polish households. Inthese salt samples analysed was the concentration of natural radioactive isotopes like radium,thorium and potassium with use of Mazar type gamma radiation spectrometer connected witha scintillation probe NaI (Tl). Concentration of 226Ra and 232Th isotopes in the tested salt sampleswith reduced sodium content amounted to below the background level of determination, and the40K content was within the limits 3386–5794 Bq∙kg-1. Additionally on the basis of the establishedconcentration of natural radioactive isotopes, the annual loading effective dose was calculated forwomen and men classified to the group of adults from the point of view radiological protection.The effective dose limit of 1 mSv∙y-1 was not exceeded for any test subject consuming reducedsodium salts.. The obtained results were compared with reported data from other countriesavailable in the literature.

Assessment of Radiological Safety of Ceramic Tiles Commonly Used in Polish Buildings.

The concentration of natural radionuclides 226Ra, 232Th and 40K in ceramic tiles manufactured in Poland is presented in this paper. The concentration of natural radioactive isotopes in the tested samples was determined using a low-level digital gamma ray spectrometer equipped with an HPGe semiconductor detector. The mean concentrations of 226Ra, 232Th and 40K in the analyzed samples were found to be 48 ± 3 Bq∙kg-1, 49 ± 3 Bq∙kg-1 and 476 ± 23 Bq∙kg-1, respectively. The world mean concentrations of these radionuclides (50 Bq·kg-1, 50 Bq·kg-1 and 500 Bq·kg-1, respectively) were not exceeded. Furthermore, in order to ascertain the level of gamma radiation exposure, fundamental radiation protection parameters were established: radioactivity concentration indicator/gamma ray indicator (Iγ), indoor dose rate (Din) and annual indoor effective dose (Ein). In the case of the investigated ceramic tiles, it was established that the parameters were not higher than the limit values, except the indoor gamma radiation dose rate which was found to be 1.5 times higher than the world average. Therefore, the findings of this study indicate that the utilization of the examined ceramic tiles in constructions should be approached with a degree of caution.

Concentration of 226Ra in soil, water, and sediment of active and abandoned quarries in southern Vietnam and environmental risk assessment: experimental and modeling studies.

Open-pit mining disturbs the earth's surface, impacts geological characteristics, and releases many pollutants including heavy metals, radionuclides, and poisonous gases into the environment. This study investigated the difference between the activity levels of 226Ra radionuclide in the abandoned quarry region (region A) and the active quarry region (region B). In the surface soil, the mean values of activity concentrations were 40 Bq kg-1 and 55 Bq kg-1 in region A and region B, respectively. The statistical analysis shows that the obtained values of 226Ra concentrations in Region B are higher and more dispersed than those in Region A. For four study quarry lakes, the ranges of activity concentrations in water and sediment were (0-19.4 mBq L-1) and (25-71 Bq kg-1), respectively. The levels of 226Ra in lake water are within the recommended value of 0.74 Bq L-1 of the United States Environmental Protection Agency (USEPA) for radiation safety. This water can be considered for drinking, agricultural irrigation, and fish farming. The Revised Universal Soil Loss Equation (RUSLE) estimated the soil loss due to soil erosion in the abandoned quarries. It was predicted that the soil erosion degrees in the study area were from very low class to moderately high class according to soil loss classification. The Quantitative Water, Air, Sediment Interaction (QWASI) was validated to predict 226Ra activity concentrations in the water and sediment of quarry lakes. Based on Student's t-test, the predicted values of 226Ra activity concentrations for study quarry lakes agreed with the measured values (confidence interval 95%).

Investigation into the geological radiation levels and evaluation of hazard parameters in soil and rock specimens taken from mining sites across North-Eastern Nigeria

This research quantitatively evaluates the natural radioactivity levels and geological radiation hazard parameters of soil and rock specimens obtained from mining locations in North-Eastern Nigeria, by means of grammar-ray spectroscopy. There have been potential public health risks associated with the use of soil and rock from mining locations in North-Eastern Nigeria, specifically the study areas. A total of twenty-eight samples were systematically gathered from Nahuta and Kashere locations. Through gamma spectrometry employing a NaI (TI) detector, the natural radioactivity levels of 238U, 232Th and 40 K were determined for each and every sample. The findings indicated that the mean activity concentrations of 226Ra, 232Th, and 40 K in Nahuta are 46.13 ± 4.78 Bq/Kg, 34.10 ± 3.02 Bq/Kg and 473.94 ± 5.41 Bq/Kg for the soil samples respectively, and 32.91 ± 0.49 Bq/Kg, 40.70 ± 0.41 Bq/Kg, and 578.18 ± 4.28 Bq/Kg for the rock samples respectively. The corresponding mean activity concentrations of 226Ra, 232Th, and 40 K in kashere are 17.99 ± 4.18 Bq/Kg, 23.73 ± 1.78 Bq/Kg, and 191.65 ± 3.15 Bq/Kg, for the soil samples, and 20.24 ± 3.72 Bq/Kg, 29.09 ± 1.78 Bq/Kg, and 148.36 ± 3.15 Bq/Kg, for the rock samples respectively. An analysis of radiation risk parameters (D, AEDE, Raeq, Hex, Hin, AGDE and ELCR) has been conducted and findings explored. While the samples from the kashere region fall within the international recommended levels, elevated readings of certain radiation health parameters are observed in the Nahuta region, posing serious public health risk due to utilization of the soil and rock from this area in construction activities.

Comparative dose assessment of natural radioactivity in building materials: Empirical equation vs. RESRAD Build computer code

This study focuses on the dose assessment of radioactivity in 18 samples of building materials collected from different locations which used in building construction in Duhok City. NaI(Tl) scintillation detectors was used to measure the natural radioactivity of these samples. The dose analysis was conducted using two distinct methods: empirical equations and the RESRAD Build computer code software. The concentrations of 226Ra, 232Th and 40K in the samples were found to range from 10.6 ± 0.7 to 25.5 ± 3.1 Bq.kg−1, 6.9 ± 2.0 to 16 ± 2.2 Bq.kg−1, and 32 ± 5.6 to 65 ± 8.1 Bq.kg−1, respectively. The dose assessment results obtained from both methods showed good agreement, with each method having its respective strengths. Importantly, all radiological hazard index for all samples and the dose assessment that was conducted by RESRAD code over a 50 – year period was below the worldwide safety limits. This comprehensive assessment provides valuable insights for ensuring the responsible use of construction materials in building projects across the region.

Monte Carlo simulations of radiological cancer risks associated with naturally occurring radionuclides in local and imported spices from Delta and Ogun States, Nigeria

ABSTRACT Naturally occurring radionuclides in soil, water, and plants, including spices, pose potential health risks. Given the widespread use of spices in culinary practices, it is crucial to assess the potential health risks associated with their natural radionuclides content. This study determines the activity concentrations of natural radionuclides in locally processed and imported spices from markets in Delta and Ogun States, Nigeria, using gamma spectrometry. Monte Carlo simulations estimated the probabilistic distribution of cancer risk over a lifetime of exposure. The results revealed significant variability in the activity concentrations of 40K, 226Ra, and 232Th among the spice samples. The mean committed effective doses due to ingestion were 10.56 µSv/y, 9.82 µSv/y, and 6.87 µSv/y for locally produced and imported spices, respectively. Both deterministic and probabilistic analyses show that the cancer risk values fall within the acceptable range of 10-6 to 10-4, indicating minimal risk from ingestion of natural radionuclides in spices.

Trace element and radiological characterisation of ash and soil at a legacy site in the former Raša coal-mining area.

Coal mined in the shut-down Raša mine in Istria, Croatia had a high organic sulphur content. What has remained of its local combustion is a coal and ash waste (legacy site) whose trace element and radionuclide composition in soil has enduring consequences for the environment. The aim of this study was to follow up on previous research and investigate the potential impact on surrounding soil and local residents by characterising the site's ash and soil samples collected in two field campaigns. Trace elements were analysed using particle induced X-ray emission (PIXE) analysis. Radionuclides, namely 232Th, 238U, 226Ra, 210Pb, and 40K, were analysed with high resolution gamma-ray spectrometry. PIXE analysis confirms previous findings, whereas radionuclide analysis shows higher activity concentrations of 238U, 226Ra, and 210Pb in ash samples than the worldwide average, and the absorbed dose rates for local residents are up to four times higher than background levels. Our findings confirm the need of investigating coal industry legacy sites and the importance of remediation of such sites.

Radionuclides Determination and Hazard Indices Assessment of NORM Contaminated Soil for Oil Fields in Southern Iraq

Oil and gas extraction greatly impacts the environment due to the existence of natural radionuclides in crude oil. Uncontrolled dealing with the extraction can lead to radiological contamination. This research aims to determine the radioactivity concentration of naturally occurring radioactive materials (NORM) and risk assessment of contaminated soil in oil fields. Three oil fields in Al- Basra government southern of Iraq were investigated; 45 soil samples were collected from several locations, the first group of soil samples from Al Rumaila southern oil field, the second group was collected from Khudair Almay storage site, and the third group collected from a waste pit near an oil-well in Majnoon oil field. High purity germanium (HPGe) detector was used to determine the radioactivity concentrations of radionuclides of the series 238U and 232Th as well as 40K. The mean concentration of 226Ra, 228Ra, and 40K was found in the soil samples of the first group: 5.625×104±1.5%, 5.157×103±1.43%, and 1.744×103±5.7% Bq kg-1, respectively, 1.07×105±1.5%, 7.90×103±1.43% and 8.33×102 ±5.7% Bq kg-1, respectively for the second group and 4.85×102±5.7%, 5.5×101±9% and 1.65×103±15.9% Bq kg-1, respectively for the third group. The hazard indices, total radium equivalent, representative gamma level index, and annual effective dose equivalent were calculated to estimate the potential radiological health risk in these oil fields. The results fluctuate as acceptance in some samples of the third group and not acceptance in most of the first and the second group soil samples. The statistical analyses of data show a high positive correlation coefficient (r= 0.996) with significant p-value (p≤0.05) and coefficient of determination (R2= 0.993) between 226Ra and 228Ra in the first and second groups soil samples, whereas there is no correlation in the third group.

The Natural Radioactivity and Accompanying Radiation Hazard in the Tigris River Sediments in Baghdad, Iraq

The natural radioactivity in the sediments of the Tigris River was measured using gamma spectrometry using an HPGe detector. Ten sediment samples were collected, and the target radionuclides are 226Ra, 232Th and 40K. Radioactivity in sediment was investigated in clay and silt fractions beside the hazard indices. The 226Ra concentration ranged between 6.5 and 11.2 Bq/kg, 232Th from 4.1 to 9.6 Bq/kg, and 40K from 133.8 to 260.2 Bq/kg. The average values of the natural radionuclides of these elements are within the worldwide average or less and comparable to those of the rivers in other countries; accordingly, the radiological hazard indices such as absorbed dose rate, annual effective dose equivalent, hazard indices and gamma index are below the recommended international values, indicating no significant hazard. The study concluded a positive relationship between the radioactivity and clay and silt content.

Disequilibrium in natural decay series in samples from Czech water treatment plants: Uranium, radium and thorium isotopes determination

In the Czech Republic, underground or mixed source water treatment plants are classified as the workplaces with possible increased exposure from a natural source of radiation. When releasing waste materials or residues from these NORM workplaces into the environment, the content of natural radionuclides is measured and compared with the clearance levels established by Czech legislation. The content of natural radionuclides in solid samples is determined primarily by high-resolution gamma-ray spectrometry. Six radionuclides, 238U, 228Th, 226Ra, 228Ra, 210Pb, 40K, are measured directly or by their measurable decay products (assuming equilibrium), the activity concentration of the other four radionuclides, 234U, 230Th, 210Po, 232Th is conservatively estimated. The study is focused on mapping the properties of NORM arising from the treatment of groundwater and, based on the real samples measurement, verification of new proposed assessment approach. It was tested whether the knowledge of the content of natural radionuclides in water can be practically used to estimate the content in NORM. Samples of water, filter material or sludge were taken from 16 different water treatment plants. Combination of gamma-ray spectrometry and radiochemical methods were applied to determine the content of radionuclides 234U, 238U, 226Ra, 228Ra, 228Th, 230Th and 232Th in solid NORM, and radionuclides 234U, 238U, 226Ra, 228Ra in water. Based on the results the proposed modification of the assessment was verified.

Physicochemical and spatial distribution patterns of radon and its parent radionuclides in the uranium-mineralized Singhbhum Region, India

AbstractThis study examined the distributions of radon and its parent radionuclides 226Ra and 238U in groundwater samples from the Singhbhum region, Jharkhand, India. Radon showed a heterogeneous spatial distribution pattern, with a lognormal distribution. A good correlation between radon bubbler-Lucas cells and liquid scintillation counting techniques was observed for radon monitoring. 222Rn and 226Ra were negatively correlated with pH, suggesting the mobilization of radionuclides at low pH. Uranium was positively correlated with common ions (e.g., Ca, Mg, and SO42−). The activity ratios among the radionuclides indicated disequilibrium, with 222Rn origin controlled by parent radionuclide activity in bedrock. The 226Ra and 238U concentrations in groundwater were lower than the limits recommended by the WHO.

Assessment of natural radioactivity levels in polymetallic nodules and potential health risks from deep-sea mining

The activity concentration of U-238, Ra-226, Pb-214, Bi-214, and Pb-210 was measured in samples of polymetallic nodules stored in the repository of the Interoceanmetal Joint Organization (IOM) based in Szczecin, Poland. The nodule samples were collected from the seabed of the Pacific Ocean, within the Clarion-Clipperton Zone, approximately 2000 kilometres west of Mexico. The activity concentration of U-238 in the studied samples ranged from 9 to 51 Bq/kg. The mean activity concentration of the other radionuclides, Ra-226, Pb-214, Bi-214, and Pb-210, was found to be at comparable levels at 350, 321, 323, and 287 Bq/kg, respectively. Also investigated was the potential radiological hazard to individuals involved in the storing and processing of the nodules, resulting from the radioactive decay of Ra-226 contained in the nodules. It was concluded that the effective dose limit (20 mSv) for individuals occupationally exposed to radioactive material can be exceeded in the case of prolonged and close contact with large quantities of nodules. Effective protective measures against the detected radiation include: observing the exposure time, ensuring safe distance from the source of radiation, and selecting suitable shielding where feasible within the operational constraints of the nodule transport or storage system.

An assessment of radiological risks and chemical toxicity due to naturally occurring radionuclides in surface waters of a semiarid region in Brazil

Santa Quitéria, a city in northeastern Brazil, faces significant challenges in ensuring the availability of potable water due to its semi-arid climate and limited water resources. This study investigates the radiological quality of surface waters commonly used by the population for drinking and by animals for hydration. Water samples were collected from six different locations over a 25-month period, and the concentrations of naturally occurring radionuclides were measured using spectrophotometric analysis, total alpha, and gross beta counting. The mean activity concentrations of Unat, 226Ra, 210Pb, 232Th, and 228Ra were determined to be 9.89∙10−2, 5.35∙10−2, 5.86∙10−2, 6.89∙10−3, and 2.81∙10−3 Bq∙L−1, respectively. Statistical methods, such as cluster and factor analysis, were applied to understand the distribution patterns of these radionuclides. The study also estimated dose rates from radionuclide intake, with a maximum value of 108.5 µSv·y−1, and compared the results against dose limits set by relevant organizations. Furthermore, the risks of morbidity and mortality from radionuclide intake were assessed, revealing the need for optimization at one sampling point where the health risks exceeded intervention thresholds.

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 4⁰K were determined for 27 oases. These oases were located in three southern Tunisian governorates. The activity concentration of 22⁶Ra, 232Th, and 4⁰K was measured using a 3 × 3 inch NaI(Tl) scintillation detector, which was found to be 21.82 ± 1.0 , 26.51 ± 1.1 , and 559.21 ± 23.0 , respectively, for traditional oases and 26.56 ± 1.2 , 24.45 ± 1.1 , and 661.28 ± 26.3 , 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.

Assessment of Activity Concentration and Health Hazards of Radiation Exposure in Soil from Mamara Jidda and Waja Tin Mining Sites in Northern Nasarawa State, Nigeria

Natural background radiation exposure is an inevitable occurrence on Earth, and humans are exposed to radiation in their surroundings whether consciously or unconsciously. However, increased artisanal and illegal mining could harm the local environment and increase background radiation levels, affecting the community's overall health. This study assessed the activity concentration of primordial radionuclides (226Ra, 232Th, and 40K) from soil samples obtained from Mamara Jidda and Waja tin mine sites in Nasarawa State, Nigeria, and its risk to human health. The gamma spectroscopy using a Sodium iodide-thallium activated detector was used to measure the activity concentrations of primordial radionuclides in the surface soils/sediments samples. The activity concentrations of 226Ra, 232Th, and 40K for Mamara Jidda and Waja were found to be within the range of 4 - 18 Bq kg-1, 41 - 105 Bq kg-1, and 524 - 717 Bq kg-1; 13 - 40 Bq kg-1, 75 - 134 Bq kg-1, and 591 - 882 Bq kg-1 respectively. The average values show that 40K and 232Th concentrations are above the recommended limit set by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in Mamara Jidda and Waja mine sites. The annual gonadal dose equivalent (AGDE), annual effective dose rate (AEDE), radium equivalent (Raeq), absorbed dose rate (D), and external hazard index (Hex) for Mamara Jidda and Waja were found to be 0.56 mSv yr-1, 0.10 mSv yr-1, 588.58 Bq kg-1, 78.26 nGy hr-1 and 0.46; 0.73 mSv yr-1, 0.13 mS yr-1, 742.74 Bq kg-1, 103.72 nGy hr-1 and 0.61 respectively. The AEDE and Hex are below the recommended safety limits. However, the high values of AGDE in both mining sites and D in Waja mine demonstrate that with continuous exposure to radiation, a significant genetic impact is eminent to the miners and inhabitants of these areas. Also, the Raeq values for both mines suggest that their soils are unsafe for use as building materials.

Elevated Plasma IL-6 Coincides with Activation of STAT3 in PBMC After Acute Resistance Exercise.

Changes in plasma concentrations of anti-inflammatory cytokines, such as interleukin-6 (IL-6) and IL-10, after acute resistance exercise (RE) have been widely explored. Whether observed changes in plasma cytokine concentration correspond to the activation of anti-inflammatory signaling pathways in immune cells after acute RE is unknown. This study aimed to determine if changes in plasma cytokines after acute RE resulted in the activation of anti-inflammatory signaling pathways in peripheral blood mononuclear cells (PBMC). Healthy young males (N = 16; age = 23.5 ± 2.7 yr; BMI = 22.4 ± 1.7 kg·m-2) participated in a single session of whole-body RE (4 sets of 4 different exercises at 70% 1-repetition maximum with the last set to failure) and a sedentary control (CON) condition in a randomized crossover design. Blood samples were collected at several time points before and after the exercise bout. Higher plasma IL-6, IL-10, and IL-1 RA concentrations were observed after RE compared with CON. Phosphorylation of STAT3 and protein expression of SOCS3 in PBMC were increased in RE compared with CON. The elevation of plasma IL-6, but not IL-10, coincided with the activation of STAT3 signaling in PBMC. These results highlight a potential mechanism by which RE may exert anti-inflammatory actions in circulating immune cells.

The Effect of Heating Rate on the Microstructure Evolution and Hardness of Heterogeneous Manganese Steel.

The use of a rapid heating method to achieve heterogeneity of Mn in medium-manganese steel and improve its comprehensive performance has been widely studied and these techniques have been widely applied. However, the heating rate (from α to γ) has not received sufficient attention with respect to its microstructure-evolution mechanism. In this study, the effect of heating rate on the microstructure evolution and hardness of heterogeneous medium-manganese steel was investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and DICTRA simulation. The results showed that the Mn distribution was heterogeneous in the initial microstructure of pearlite due to strong partitioning of Mn between ferrite and cementite. At low heating rates (<10 °C/s), the heterogeneity of Mn distribution was diminished to some extent due to the long-distance diffusion of Mn in high-temperature austenite. Contrastingly, at high heating rates, the initial heterogeneity of the Mn element could be largely preserved due to insufficient diffusion of Mn, which resulted in more ghost pearlite (GP: pearlite-like microstructure with film martensite/RA). Moreover, the high heating rate not only refines the prior austenite grain but also increases the total RA content, which is mainly composed of additional film RA. As the heating rate increases, the hardness gradually increases from 628.1 HV to 663.3 HV, due to grain refinement and increased dislocation density. Dynamic simulations have also demonstrated a strong correlation between this interesting microstructure and the non-equilibrium diffusion of Mn.

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 40K) 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 40K 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 ± 45.7Bqkg-1, with an average value of 13.0 ± 1.0, 21.7 ± 1.0, and 243.7 ± 25.2Bqkg-1, respectively. The average of Raeq in the study region lies within the safe limit of 370Bqkg-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 40K 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.