Isotopes in Environmental and Health Studies最新文献

Rare earth element (REE) surface deposits containing primordial radionuclides such as uranium (²³⁸U), thorium (²³²Th), and potassium (⁴⁰K) were identified in the Dong Pao region, northern Vietnam. As the area is inhabited, an in-depth investigation assessed environmental radioactivity, radiation doses, radiobiological parameters, and DNA alterations to evaluate health risks. Investigations were conducted in the REE deposit area and a control area 20 km away. Soil, water, and locally produced foods were analysed by gamma spectrometry to determine concentrations of ²³²Th, ²²⁶Ra, and ⁴⁰K, allowing estimation of annual effective doses from external gamma radiation. Ambient dose equivalent was measured with a survey meter and compared with dose estimates based on soil activity concentrations. Effective doses from ingestion were calculated from radionuclide concentrations in food and water. Inhalation doses were estimated from indoor ²²²Rn and ²²⁰Rn concentrations measured by solid-state nuclear track detectors in dwellings of both areas. Hematological parameters were analysed in blood samples using ADVIA2120 equipment. Peripheral blood counts of both groups were within normal ranges. t-tests revealed significant differences in neutrophil and lymphocyte counts in white blood cells of females from the REE area compared to controls. Neutrophil-to-platelet and platelet-to-lymphocyte ratios in adult females from the ore deposits area were significantly higher, indicating possible inflammation, an early sign of cancer. TP53 gene sequencing showed significantly higher genotype frequencies of rs137852793 and c.701 + 25 variants in individuals from the REE area. Results clearly indicate that ionising radiation from REE ore deposits poses a health hazard to the local population, particularly females. Polymorphism of the TP53 gene may serve as a biomarker for radiation exposure.

This study investigates the natural radioactivity levels of ²³⁸U, ²³²Th, and ⁴⁰K in soil samples using a NaI (Tl) gamma-ray spectrometer. The primary objective was to determine the activity levels of radionuclides such as ²³⁸U, ²³²Th, and ⁴⁰K in soil samples and to assess the related radiological risk. Based on these measurements, several radiological parameters, including radium equivalent activity (Ra_eq), outdoor absorbed dose rate (ADR_out), annual effective dose equivalent (AEDE_out), excess lifetime cancer risk (ELCR_out), external hazard indices (H_ex), and annual gonadal dose equivalent (AGDE), were calculated. Additionally, the effective radiation dose to specific body organs (D_organ) was estimated to evaluate the potential biological impact of external gamma radiation exposure. The results indicate that the activity level of ²³⁸U slightly exceeds the world recommended limit of (35 Bq kg^-1), while the calculated radiological variables such as ADR_out (101 ± 13 nGy h^-1), AEDE_out (0.12 ± 0.02 mSv y^-1), ELCR_out (0.43 ± 0.08), and AGDE (366 ± 48 µSv y^-1) were slightly higher than the internationally recommended safety limits. Multivariate statistical analysis was performed, helping to identify potential sources and interrelationships among the measured radionuclides and radiological variables.

Soil serves as both a repository and a pathway for natural radioactivity, influencing human exposure through the transfer of radionuclides into the food-chain and atmosphere. Industrial activities can further disrupt this distribution by introducing contaminants, potentially leading to environmental accumulation. This pioneering study investigates the activity concentrations of naturally occurring radioactive materials (NORMs) and assesses radiological hazards in soil from the Bangladesh Small and Cottage Industries Corporation (BSCIC) Industrial Area in Jhenaidah, Bangladesh. Thirty soil samples were systematically collected at radial distances of 100, 400 and 800 m from the industrial center. The range of activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 20 ± 2 to 35 ± 3, 23 ± 2 to 55 ± 4, and 420 ± 32 to 610 ± 51 Bq kg^-1, respectively, while the activity concentrations of certain ²²⁶Ra, most ²³²Th, and all ⁴⁰K exceed the global average values of 30, 35, and 400 Bq kg^-1, respectively. Notably, ⁴⁰K levels remain relatively consistent across the study area, whereas ²²⁶Ra and ²³²Th concentrations tend to decrease with increasing distance from the industrial site. The elevated radionuclide levels may be attributed to local geological formations rich in heavy minerals, industrial processes that redistribute these elements, and anthropogenic activities such as waste disposal and construction. Additionally, Sample 16 (23.5422849°N, 89.1951063°E) exhibited trace amount of ¹³⁷Cs (1.84 ± 0.26 Bq kg^-1), indicating possible contamination from past nuclear fallout events such as Chernobyl or Fukushima. While radium equivalent activity and hazard indices remain within safety limits, certain outdoor absorbed dose rates, external effective doses, gamma representative level indices, and excess lifetime cancer risks exceed recommended thresholds, raising concerns about potential long-term health risks. These findings underscore the need for cautious land use planning, particularly for agricultural and construction purposes. Furthermore, this study provides essential baseline data to monitor radioactivity in industrial zones before the commissioning of the Rooppur Nuclear Power Plant.

Invasive plants pose a significant threat to ecosystems by disrupting the ecological balance, which includes the alteration of biogeochemical processes. Among the most aggressive invaders is Fallopia japonica, a species that thrives in riparian zones - critical interfaces between aquatic and terrestrial environments - where it significantly impacts biodiversity and ecosystem functions. Despite its success as an invader, the mechanisms that drive both the impact and success of F. japonica upon ecosystem processes remain poorly understood. Prior studies have suggested that F. japonica may exhibit traits such as a unique preference for ammonium over nitrate, potentially altering nitrogen availability for native plants like Urtica dioica. Additionally, it has been proposed that the species leverages phenolic compounds to influence soil biogeochemistry and nitrogen cycling. However, these processes lack comprehensive investigation. Using stable isotope labelling (¹⁵N and ¹³C), we found that, contrary to prior assumptions, F. japonica showed an overall lower uptake of both ammonium and nitrate relative to the native competitor, U. dioica. Although we expected a preference for ammonium, F. japonica instead exhibited a slight preference for nitrate. In addition, F. japonica demonstrated higher nitrogen-use efficiency and allocated more freshly assimilated carbon and nitrogen to root growth than U. dioica. These findings suggest that traits such as efficient nitrogen use and strategic root allocation may contribute to F. japonica's ability to establish itself in nitrogen-variable environments like riparian zones. By prioritising belowground biomass during early development, F. japonica may gain a competitive advantage that enables it to disrupt native plant communities and alter ecosystem dynamics. This study underscores the value of stable isotopes in understanding plant-soil interactions and informs strategies for managing invasive species in sensitive ecosystems.

Stable isotopes are crucial for understanding water cycles and climate dynamics, particularly in tropical regions. However, establishing and maintaining precipitation sampling stations in Southeast Asia is challenging due to high costs and logistical issues. Consequently, many areas in this region have limited or no sampling stations with adequate stable isotope data. To address this problem, developing models that simulate stable isotope contents using machine learning (ML) techniques, especially deep learning, is a promising solution. In this study, the influence of large-scale climate modes (teleconnection indices) and local meteorological parameters on the stable isotope contents of precipitation was examined across six key stations in Southeast Asia, including Bangkok, Kuala Lumpur, Jakarta, Kota Bharu, Jayapura, and Singapore. A deep neural network (DNN) model was applied for simulation, and its performance was compared with a partial least squares regression (PLSR) model using various evaluation metrics. The DNN consistently demonstrated superior accuracy across all studied stations, highlighting the efficacy of DNNs, in accurately simulating stable isotope contents in tropical precipitation. The importance ranking derived from the SHapley Additive exPlanations (SHAP) technique aligns perfectly with the results obtained from the DNN importance function. In addition, the SHAP summary plot highlights the contributions of key features, such as precipitation and potential evaporation, to the model's predictions. The dependence plots further illustrate the relationship between these features and the predicted response, revealing nonlinear interactions that influence model behaviour. This research provides new insights into the complex interactions between large-scale climate drivers and local weather patterns, advancing the use of ML for isotope-based climate studies. The techniques used in this study offer a framework for applying ML to isotope analysis in tropical climates and can be extended to similar regions worldwide.

In Harnai, Balochistan, Pakistan, the levels of ²²⁶Ra and ²²²Rn were measured with a high purity germenium (HPGe) detector and a RAD7 detector, respectively, in drinking water. The concentration of ²²²Rn in the spring water under investigation ranged from 2.8 ± 0.59-8.5 ± 0.80 Bq L^-1 with an average of 4.96 ± 0.7 Bq L^-1, while the concentration of ²²⁶Ra varied from 1.36 ± 0.55-6.8 ± 0.99 mBq L^-1 with an average of 3.54 ± 0.74 mBq L^-1. All concentrations of ²²²Rn and ²²⁶Ra were found to be below the global averages of 11.1 Bq L^-1 and 555 mBq L^-1, respectively. There was a positive connection (R² = 0.9398) between the concentrations of ²²²Rn and ²²⁶Ra. There are very weak associations between phyco-chemical characteristics and ²²²Rn and ²²⁶Ra. For various age groups, the estimated annual effective dosages from ingesting of ²²⁶Ra and ²²²Rn were determined to be below the advised threshold of 0.1 mSv y^-1. Based on the results, it has been concluded that the population in the research region is not significantly affected by ²²⁶Ra and ²²²Rn in spring water.

Due to the dramatic rise in global population and intensified agricultural activities, groundwater environments are increasingly threatened by nitrate pollution. To elucidate the sources and transformation processes of nitrate contamination in rural karst groundwater, this study selected the Pingyin karst catchment in Shandong Province, northern China, as the research area. This study employed a combination of isotopic analyses (δ¹⁵N-NO₃, δ¹⁸O-NO₃, δ²H-H₂O, and δ¹⁸O-H₂O) and hydrochemical data to investigate karst groundwater, pore groundwater, and Yellow River water. In the study area, nitrate concentration in karst groundwater samples ranged from 11 to 294 mg/L, with 80 % of samples exceeding the WHO safe drinking water limit of 50 mg/L for NO₃. Stable isotopic results (δ²H-H₂O, δ¹⁸O-H₂O) show meteoric precipitation is the main source of groundwater recharge. The ¹⁸O-Cl relationship bubble diagram revealed that nitrate contamination primarily originated from anthropogenic sources. Furthermore, both hydrochemical (e.g. TIN vs. Cl, NO₃/Cl vs. Cl) and isotopic (δ¹⁵N-NO₃ vs. δ¹⁸O-NO₃) evidence indicate that untreated human and livestock wastewater is the primary contributor to elevated nitrate levels in groundwater. Isotopic analysis also revealed that nitrification is the dominant biogeochemical process occurring in groundwater. The MixSIAR model further estimated source contributions as follows: manure and sewage (49.92 %), soil nitrate (39.43 %), chemical fertilizers (9.19 %), and atmospheric deposition (1.46 %). Finally, based on these findings and considering the environmental conditions of the study area, environmental protection strategies to prevent nitrate pollution were proposed. These findings serve as a valuable reference for promoting the sustainable use and pollution control of karst groundwater in rural areas.

Farmers and residents of homes built with soil bricks may be impacted by naturally occurring radionuclides in farmed soil. Using high purity germanium (HPGe) and sodium iodide (NaI) detectors, soil samples from apple orchards in Pishin have been examined to look into radioactive materials and related health impacts. The average values of ²²⁶Ra were 22.71 and 15.19 Bq kg^-1, respectively, while those of ²³²Th were 29.84 and 14.62 Bq kg^-1, respectively. The values of ⁴⁰K were 329.48 and 113.08 Bq kg^-1 using HPGe and NaI detectors, respectively. It was discovered that each of these values was below the 35, 45, and 420 Bq kg^-1 permissible limits. Positive correlations (R² = 0.912 for ²²⁶Ra), (R² = 0.9148 for ²³²Th) and (R² = 0.9026 for ⁴⁰K) were found among the results obtained from HPGe and NaI detectors. The average radium equivalent activity (Ra_eq) values obtained from both methods were 90.77 and 44.81 Bq kg^-1, respectively, which were lower than the world average. The average results for outdoor and indoor absorbed doses and outdoor and indoor annual effective doses from the HPGe and NaI detectors were also found to be within the respective permissible limits. It was discovered that the alpha (Iα) and gamma (Iγ) indices were below the limit. Thus, it is determined that farmers and residents of homes constructed with soil bricks are not at risk for any health problems from the soil in the studied region.

Ongoing changes in climate alter the role of forests in the hydrologic cycle, influencing water transmission to springs and aquifers. Here we compared two forests dominated by either beech or spruce on broadly similar soils (Dystric Cambisols); we monitored the passage of natural-abundance stable isotope signals through the upper meter of soil and onward to springs. The isotopic data were similar between the sites at every time step and at every stage of transit, except at 90-100 cm depth, where the isotopic signal of the beech forest was delayed by approximately 1 month. The data were used in a lumped parameter dispersion model so that physical parameters describing transport could be determined and compared. Modeled residence times were similar between the two forests (123 (sd = 32) vs. 152 (25) days), with high precision to depths of 40 cm. According to the model, rainfall reached 1 meter depth in 200 (8) days under the spruce stand, but required 228 (37) days in the beech. The measurements below the rooting zone (90-100 cm) play a critical role in detecting site/species differences and in prediction of residence times.

Environmental radioactivity is significantly elevated by coal combustion, posing risks to communities living near coal-fired thermal power plants (CFTPPs). This study presents the first comprehensive assessment of radiological impacts around the Rampal Thermal Power Plant, a 1320 MW facility located in Rampal Upazila, near the UNESCO World Heritage site of Sundarbans, Bangladesh. Thirty soil samples were systematically collected from distances of 100, 500, 1000, 2000, and 3000 m from the power plant. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in soil ranged from 17-31, 29-51, and 350-670 Bq kg^-1, respectively, with a few samples exceeding the population-weighted global averages for ²²⁶Ra (32 Bq kg^-1) and ²³²Th (45 Bq kg^-1), and almost all the samples exceeding the average for ⁴⁰K (420 Bq kg^-1). The elevated levels of ²²⁶Ra, ²³²Th, and ⁴⁰K in the soil samples can be attributed to several interconnected factors, including the presence of thorium-rich minerals such as monazite and zircon, granitic geological formations, and anthropogenic inputs like bottom ash discharge from the plant and coal combustion byproducts. While the radium equivalent activity and hazard indices generally fell within safety limits, the higher outdoor and indoor absorbed dose rates, effective doses, and increased lifetime cancer risk raised alarms about potential health threats for nearby residents over time. Moreover, the long-term radiological effects on the Sundarbans ecosystem could disturb its fragile balance, impacting both biodiversity and the local communities that rely on its resources. These results highlight the necessity for further evaluations and remediation efforts to ensure the safe use of these soils in agricultural and construction activities. This research also seeks to develop a radiological distribution map, which will provide crucial baseline data for the forthcoming Rooppur Nuclear Power Plant.