Isotopes in Environmental and Health Studies最新文献

The present research aimed to characterize the temporal variation in the compositions of stable isotopes ($\delta D$ and δ¹⁸O) at Senai in Johor, Malaysia. Long-term monthly data collected from Malaysian Nuclear Agency and the International Atomic Energy Agency (IAEA)/World Meteorological Organisation (WMO), Global Network for Isotopic Precipitation (GNIP) for a period of 2013-2021 were considered. The isotopic composition was evaluated monthly, seasonally and annually by taking into account the amount of precipitation (rainfall), temperature and relative humidity. The δD and δ¹⁸O values showed enriched values in the months of January, February and March and depleted values in November and December, respectively. Considering the seasonal characteristics at Senai site, it was found that the precipitation during the northeast monsoon (NEM) showed a slight enrichment in isotopic compositions as compared to the rainfall during the southwest monsoon (SWM). The primary sources of moisture were identified through the modelling of HYSPLIT-based backward trajectories, which indicated that the Pacific Ocean, the South China Sea (NEM season) and the Indian Ocean (SWM season) play significant roles as moisture contributors. Additionally, landmasses in the western Pacific and northern continental regions also supplied moisture that influenced the composition of stable isotopes in precipitation in Senai. The findings of this study contribute to a deeper comprehension of the hydrometeorological processes at play in the study area, which affect the fluctuations of compositions of stable isotopes in precipitation within the region. Further, a more comprehensive investigation of δ¹⁸O and δD isotopes is deemed crucial as essential climate response variables. This research will enhance our understanding of the hydrological cycle and improve predictions regarding the impacts of future climate change and alterations in ecosystems.

This study examines the concentrations of radon, radium, and uranium, along with the annual effective dose and excess lifetime cancer risk due to ingestion of radon in vegetable and fruit samples collected randomly from eleven sites in the Ranya district, Iraq. The solid state nuclear track detector CR-39 was used to monitor radon levels and their progeny. The findings demonstrate that the average concentrations of radon, radium, and uranium in vegetable and fruit samples were 91.05 Bq m^-3, 0.26 Bq kg^-1, and 0.06 ppm, respectively. These results were lower than the global average recommended by ICRP and UNSCEAR. Additionally, the average values of annual effective dose and excess lifetime cancer risk were 0.02 µSv y^-1 and 0.08 × 10^-6, respectively. These results comply with internationally recommended safe levels for human consumption. Further research is recommended to evaluate the transfer of radionuclides from soil to edible crops.

This study was carried out to evaluate the distribution of naturally occurring radioactive materials (NORM) and radiological hazard indices in the soil of a gold mine in northwestern Sudan using gamma ray spectrometry. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the soil samples varies from 2.54 ± 1.70 to 50.67 ± 3.10 Bq/kg, 10.28 ± 4.20 to 39.91 ± 2.10 Bq/kg and 274.64 ± 0.98 to 1625.85 ± 54.40 Bq/kg, respectively. The average activity concentration of ⁴⁰K were found to be above the world average. The annual effective dose is 0.05 mSv/year which is lower than the 20 mSv/year recommended by the International Commission on Radiological Protection (ICRP) guidelines for occupational exposure.

The concentrations of natural radioactivity in soil samples collected from chromite mines of two different towns, Khanozai and Muslim Bagh, districts of Pishin and Killa Saifullah, respectively, were measured using a high purity germanium (HPGe) detector. The average values of ²²⁶Ra, ²³²Th and ⁴⁰K in soil of Khanozai chromite mines were found to be 26.414, 37.321 and 404.561 Bq kg^-1, respectively. In Muslim Bagh chromite mines, these values were found to be 17.59, 29.677 and 380.475 Bq kg^-1, respectively. The maximum average values of radium equivalent (Ra_eq), external hazard index (H_ex) and internal hazard index (H_in) were found to be 110.851, 0.299 and 0.356 Bq kg^-1, respectively, in chromite mines of Khanozai, while the minimum average values were found to be 89.253, 0.276 and 0.275 Bq kg^-1, respectively, in Muslim Bagh chromite mines. Similarly, maximum average values of absorbed dose rate (D_R), external absorbed dose rate (D_out) and internal absorbed dose rate (D_in) were found to be 50.742, 54.651 and 77.058 nGy h^-1, respectively, in soil of Khanozai chromite mines while the minimum average values were found to be 41.311, 44.385 and 62.583 nGy h^-1, respectively, in Muslim Bagh chromite mines. Also, the maximum average values of annual effective dose risk (AEDR), gamma activity index (I_γ) and alpha activity index (I_α) were found to be 2.30 × 10^-1 mSv y^-1, 0.409 and 0.132, respectively, in soil of Khanozai chromite mines while the minimum average values were found to be 2.02 × 10^-1 mSv y^-1, 0.333 and 0.087, respectively, in Muslim Bagh chromite mines. The values were found to be below the world permissible range. Therefore, it is concluded that the chromite mines under the study have no health hazards.

Nitrate (${\mathrm{NO}}_3^{-}$) pollution is a serious water quality issue in many countries due to contamination of lakes, rivers, and aquifers by intensive agriculture practices and inadequate wastewater management. Nitrate pollution and associated cultural eutrophication are anticipated to increase worldwide, highlighting the need to control and reduce nitrogen pollution. The stable isotope ratios of nitrate (δ¹⁵N, δ¹⁸O) are widely used as tracers of nitrogen pollution sources. The primary technique for identifying nitrate sources has been the longstanding Kendall boxplot, despite improved methods using Bayes' theorem and the R language for estimating source fractions using hydrogeochemical context, N source data and expert assessment. This article improves the classification of aqueous nitrate sources using comprehensive published stable isotope data for nitrate from four known pollutant types and applying machine learning algorithms. AI modelling results reveal improved source depictions and offer a robust statistical framework for identifying N pollution sources. This is essential given the increased published data sources and the need for better-informed water quality management strategies.

Reducing the unrealistic simulations of different hydrological models is necessary for precise water assessment and flood forecasting. The scarcity of observed hydro-meteorological data in mountainous catchments further hinders the model's efficiency in water evaluations. This study aims to estimate the freshwater availability via characterizing the water balance employing a distributed MIKE System Hydrological European (SHE) model for the Suketi catchment of the Beas Basin, in Himachal Pradesh, India. For this purpose, the MIKE SHE/MIKE+ based model was developed for the study area using meteorological and basin-specific data. The collected samples from the rainfall, groundwater, and stream water during 2023-2024 were analysed for stable water isotopes, i.e. δ¹⁸O and δ²H. The quantitative evaluation established the efficacy of the MIKE SHE/MIKE+ based model with root-mean-square-error, coefficient of determination, Nash-Sutcliffe efficiency, and percentage bias of 76.67, 0.88, 0.92, and -0.32, respectively. The output of the developed model was integrated with the results of a two-component mixing model through the measured values of δ¹⁸O and δ²H. The local meteoric water line (LMWL: δ²H = 8.17 · δ¹⁸O + 13.11) reveals the different climatic conditions due to lower temperatures and higher latitude of the study area vis-a-vis global average. The validated water balance of the Suketi catchment infers adequate freshwater availability in the catchment with more than 74 % as baseflow to the Suketi river and evapotranspiration accounted for 64.42 % of water loss into the atmosphere.

This research aimed to measure radon activity concentrations in bottled drinking water (BDW) samples consumed in Kahramanmaraş town, Turkiye. Also, to evaluate the health risk that may occur as a result of internal irradiation resulting from ingestion and inhalation of radon in BDW samples, the total annual effective dose equivalent (AEDE) for infants, children, and adults (1-2 y, 2-12 y, and > 17 y) and excess lifetime cancer risk (ELCR) for adults (> 17 y) had to be calculated. For these purposes, 32 water samples of different volumes belonging to 8 different commercial brands, representing a large part of the BDW consumed as drinking water and sold commercially in Kahramanmaraş were collected by purchasing from markets. Radon activity amounts of BDW samples were determined using the Durridge Rad7 detector. The average value of radon activity concentrations in BDW samples was found to be 21.21 ± 1.50 mBq/L. Radon activity concentrations ranged from 13.50 ± 1.30 to 31.70 ± 2.20 mBq/L. Estimated mean total AEDE values for infants, children, and adults (1-2 y, 2-12 y, and > 17 y) were 7.43E-05, 4.39E-05, 5.43E-05 mSv y^-1, respectively. The average ELCR value calculated for adults was calculated as 2.40E-07.

This review synthesises studies from various countries that have assessed the concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in rice. Rice is a primary diet source for over 50 % of the global people, particularly in Asia. Thus, the estimation of the annual effective dose due to the ingestion of ²²⁶Ra, ²³²Th, and ⁴⁰K in rice has become an important area of study in food safety and human health risk assessment. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in rice were found by gamma spectroscopy using sodium iodide scintillation (NaI (Tl)) and high purity germanium (HPGe) detectors. Even if the activity concentration of ⁴⁰K in Thailand rice is higher than 400 Bq kg^-1, the other present rice investigations demonstrate that the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K are smaller than the world limit values of 35, 30, and 400 Bq kg^-1, respectively. Although the people of the Asia continent consume the highest rate of rice, the highest ingestion annual effective dose due to these radionuclides through consuming rice was found in Africa. It was found that the highest ingestion annual effective doses of ²²⁶Ra, ²³²Th, and ⁴⁰K from eating rice were 645.49 μSv y^-1 in Thailand, which is greater than the average value of 290 μSv y^-1 worldwide. For public health officials, researchers, and legislators who are worried about radioactive exposure from food sources, this review is an invaluable resource.

Invasive silver carp (Hypophthalmichthys molitrix) threaten Mississippi River basin ecosystems due to their ability to outcompete native species. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analysis has been used to study how silver carp impact native ecosystems, but lipids in fish tissues commonly bias their δ¹³C values. Chemical lipid extraction and mathematical equations that normalise δ¹³C values for lipid content can account for this bias, but have not been assessed for silver carp. We examined δ¹³C, δ¹⁵N, and C:N ratios before and after chemical lipid extraction using 2:1 chloroform:methanol in silver carp muscle and whole fish collected along the Mississippi River. We used linear and natural log models to estimate lipid-extracted δ¹³C values in silver carp muscle and whole fish samples based on their non-lipid-extracted δ¹³C values and elemental C:N ratios. Arithmetic models were evaluated for best fit, parsimony, and accuracy between mathematically normalised and chemically lipid-extracted δ¹³C values. Chemical lipid extraction increased silver carp δ¹³C values and decreased C:N ratio in muscle and whole fish, and increased δ¹⁵N values in whole fish but not fish muscle. While both linear and natural log models accurately estimated lipid extracted δ¹³C values, natural log models provided better fit and parsimony throughout a wide range of C:N ratios. These results confirmed the need to account for lipid effects on δ¹³C values in silver carp. Moreover, our study will allow researchers to conduct isotopic analysis without the added time and cost of chemical lipid extraction and facilitate the comparison of silver carp muscle and whole fish isotopic values across studies.

Bioindicators are living organisms that are successfully used for monitoring changes in the environmental health due to natural and/or anthropogenic influences. Dragonflies (Odonata) are considered to be good indicators of water quality; however, research on dragonflies as potential indicators of radioactivity is scarce. The aim of this study was to evaluate dragonflies as potential biological indicators of ionising radiation in nature by measuring ¹³⁷Cs activity concentrations in the dragonfly and river water samples. Altogether, 11 collective samples of dragonflies were collected from the bank of the Mura-Drava-Danube Biosphere Reserve, in the area of Virovitica-Podravina County. Following the initial sample preparation, the gamma spectrometry technique, employing an ORTEC HPGe detector system, was utilised to determine the activity concentrations of ¹³⁷Cs. The results show that the activity concentrations of ¹³⁷Cs in the river water were in the range from 4 to 13 Bq/m³. The results of dragonfly samples showed that ¹³⁷Cs was in the range from 1.7 to 3 Bq/kg. This was more than a hundred times higher than in the river Drava water. According to the obtained results, we conclude that dragonflies could be used as potential bioindicators of radioactivity.