Natural radioactivity levels and associated health hazards from the terrestrial ecosystem in Rosetta branch of the River Nile,Egypt

Twenty soil and 25 sediment samples were collected from the banks and bottom of the River Nile in the surroundings of biggest cities located close to it. Natural radioactivity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K have been evaluated for all samples by means of γ spectrometric analysis. The radioactivity levels of soil and sediment samples fall within the internationally recommended values. Nevertheless, high natural background radiation zones are detected in the Kafr El-Zayat region due to the presence of a fertilizer factory, and in the Rosetta region due to the presence of black sand deposits. The absorbed dose rate, the γ index and excess life time cancer risk are calculated. High values for some of the radiation health parameters are detected in the Kafr El-Zayat and Rosetta regions representing a serious problem to public health because the soil and sediment are used as constructing material for buildings. Furthermore, the isotope analysis of uranium for representative collected sediment samples via α spectrometry showed average specific activities of 18.7?±?3.6, 0.087?±?0.0038 and 18.6?±?3.8 Bq kg^–1 for ²³⁴U, ²³⁵U and ²³⁸U, respectively. In general, these values confirm the balance in the isotopic abundance of U isotopes.     

Simulation of natural radioactivity backgrounds in the JUNO central detector

The Jiangmen Underground Neutrino Observatory(JUNO) is an experiment proposed to determine the neutrino mass hierarchy and probe the fundamental properties of neutrino oscillation.The JUNO central detector is a spherical liquid scintillator detector with 20 kton fiducial mass.It is required to achieve a 3%/E(MeV)~(1/2) energy resolution with very low radioactive background,which is a big challenge to the detector design.In order to ensure the detector performance can meet the physics requirements,reliable detector simulation is necessary to provide useful information for the detector design.A simulation study of natural radioactivity backgrounds in the JUNO central detector has been performed to guide the detector design and set requirements for the radio-purity of the detector materials.The accidental background induced by natural radioactivity in the JUNO central detector is 1.1/day.The result is satisfied for the experiment.     

Interpolated mapping and investigation of environmental radioactivity levels in soils and mushrooms in the Middle Black Sea Region of Turkey

The activity concentration of natural (²³⁸U, ²³²Th, and ⁴⁰K) and artificial (¹³⁷Cs) radionuclides was determined in 50 samples (obtained from the same station) from various species of mushrooms and soil collected from the Middle Black Sea Region (Turkey). The activities of ²³⁸U, ²³²Th, ⁴⁰K, and ¹³⁷Cs were found as 84 ± 16, 45 ± 14, 570 ± 28, and 64 ± 6?Bq?kg^–1 (dry weight), respectively, in the mushroom samples and as 51?±?6, 41?±?6, 201?±?11, and 44?±?4?Bq?kg^–1, respectively, in the soil samples for the entire area of study. The results of all radionuclide activity measurements, except those of ²³⁸U and ²³²Th in the mushroom samples, are consistent with previous studies. In the soil samples, the mean values of ²³⁸U and ²³²Th are above the world mean, and the activity mean of ⁴⁰K is below the world mean. Finally, the activity estimation was made with both the soil and mushroom samples for unmeasured points within the study area by using the ordinary kriging method. Radiological distribution maps were generated.     

Statistical relationship between activity concentrations of radionuclides 226Ra, 232Th, 40K,and 137Cs and geological formations in surface soil of Jordan

An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg^–1, respectively. The highest mean activity concentration for ²²⁶Ra was found to be 138?±?4 Bq kg^–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg^–1 for ²³²Th, and 14.2?±?1.9 Bq kg^–1 for ¹³⁷Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of ²³²Th, ⁴⁰K, and ¹³⁷Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to ²²⁶Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg^–1, and 0.266, respectively.     

Natural radioactivity and radiation hazards assessment of soil samples from the area of Tuzla and Lukavac,Bosnia and Herzegovina

The results of activity concentration measurements of natural occurring radioactive nuclides ²³⁸U, ²³⁵U, ²³²Th, ²²⁶Ra, and ⁴⁰K in surface soil samples collected in the area of cities Tuzla and Lukavac, northeast region of Bosnia and Herzegovina were presented. Soil sampling was conducted at the localities that are situated in the vicinity of industrial zones of these cities. The measured activity was in the range from (8?±?4) to (95?±?28) Bq kg^–1 for ²³⁸U, from (0.41?±?0.06) to (4.6?±?0.7) Bq kg^–1 for ²³⁵U, from (7?±?1) to (66?±?7) Bq kg^–1 for ²³²Th, from (6?±?1) to (55?±?6) Bq kg^–1 for ²²⁶Ra, and from (83?±?12) to (546?±?55) Bq kg^–1 for ⁴⁰K. In order to evaluate the radiological hazard of the natural radioactivity for people living near industrial zones, the absorbed dose rate, the annual effective dose and the radium equivalent activity have been calculated and compared with the internationally approved values.     

Major,Minor, Trace Elements and Natural Radioactivity Content by NAA of Some Materials

By using 14 MeV neutron flux of 3.5 × 10¹⁰ n/cm² · s, the activities of the activated nuclides in both ferrosilicon alloy (from Kima-Aswan Company) and black sand samples (from the mouth of Damietta, North of Egyptian Delta), were measured. The rate dose of natural gamma-activities arising from Th-232 in the black sand area was calculated.     

Environmental and radio-ecological studies on shallow marine sediments from harbour areas along the Red Sea coast of Egypt for identification of anthropogenic impacts

Analysis of marine sediments of the studied localities provides investigators with data to characterise the composition of these sediments allowing for the identification of particular pollution sources. A study of texture, geochemistry, X-ray diffraction and natural radionuclide content of shallow marine sediments from Quseir harbour, Safaga harbour and El-Esh area in the Red Sea coast of Egypt was conducted for the purpose of assessing the possible influence of human activities on the composition of the sediments. The activity concentrations of the naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K were measured by using γ-ray spectrometry. The mean activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in all areas studied were found to be 71±6, 66±5 and 92±7 Bq kg^?1 for ²²⁶Ra, 83±5, 71±7 and 162±23 Bq kg^?1 for ²³²Th and 513±10, 493±20 and 681±28 Bq kg^?1 for ⁴⁰K, respectively. The results of the study presented were compared with corresponding results obtained in other coastal and aquatic environments in the Red Sea.     

Fissile radionuclides in thyroid of the inhabitants of the gomel region in belarus and peculiarities of their distribution

Severe radiation damages with the following substitution of connective tissue are the effect of high doses in microvolumes of the thyroid. Calcium, strontium and uranium deposited into these sections was more as compared to a normal tissue of the thyroid. An estimation of the microdistribution of fissile radionuclides was carried out using the method of fragmental radiography. The analysis of tracks done visually using a microscope magnification of 300 revealed the local density of fission fragments up to 10³ mm⁻². The irradiation of the surrounded cells which contain the hidden genetic damages, initiated by radioiodine, does not exclude their possible promoter role in thyroid cancerogenesis.     

Radioactivity concentrations in topsoil samples from the Thrace region of Turkey and assessment of radiological hazard

The activity concentrations of gamma emitting radionuclides were measured in surface soil samples from the Thrace region. ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs activities and physico-chemical parameters of the soil samples were determined in samples collected from 73 sampling stations. Radionuclide concentrations measured were compared with those found in the samples from other locations of Turkey and from different countries. The average activity concentrations of ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs were found to be 24.71 ± 8.79, 22.30 ± 7.93, 32.09±12.44, 509.00±160.05, 32.74±29.24 Bq kg^?1, respectively. The mean value of the annual effective dose equivalent from the outdoor terrestrial gamma radiation was calculated as 57.2 μ Sv.     

In situ measurements of radon levels in water and soil and exhalation rate in areas of Malwa belt of Punjab (India)

Radon concentration levels in water and soil gas from 36 locations pertaining to some areas of Malwa region of Punjab have been measured on an in situ basis using a continuous active radon detector (AlphaGuard, Model – PQ 2000 PRO, Genitron instruments, Germany). Exhalation rate measurements have also been carried out at these places, using a closed-circuit technique. The radon concentrations in soil and water varied from 1.9 to 16.4 kBq m^?3 and 5.01 to 11.6 kBq m^?3, respectively. The exhalation rate (E _Rn) ranged between 7.48 and 35.88 mBq m^?2 s^?1 with an average value of 18.17 mBq m^?2 s^?1. Annual dose rates have been calculated for water radon concentrations. The minimum to maximum values of dose rates were found to be 13.42–31.08 μSv y^?1. The recorded values of radon concentration in water are within the safe limit of 11 Bq l^?1 recommended by the US Environment Protection Agency [National Research Council, Risk Assessment of Radon in Drinking Water (Academy Press, Washington, DC, USA, 1999)]. All measurements were made in similar climatic and environmental conditions to ensure minimal variations in meteorological parameters. An intermediate correlation coefficient (0.5) was observed between radon exhalation rates and soil gas values.     

137Cs and 40K activity concentration measurements and elemental analysis in lichen samples collected from the Giresun province of northeastern Turkey

About 21 years after the Chernobyl accident, ¹³⁷Cs and ⁴⁰K activity concentration measurements using gamma-ray spectroscopy and elemental analysis using energy dispersive X-ray spectroscopy were performed in five different lichen species collected from the Giresun province of northeastern Turkey. Being a symbiosis of algae and fungi, lichens are mostly used for environmental measurements since the fungal partner is responsible for the uptake of necessary nutrients or harmful substances, such as heavy metals of radionuclides. The gamma activity results showed that ¹³⁷Cs, an artificial radionuclide released from the Chernobyl power plant accident, is still eminent in the environment of the province. The mean activity concentrations of ¹³⁷Cs and ⁴⁰K ranged from 24 to 254 with the mean value of 102 Bq kg^?1 and from 345 to 2103 with the mean value of 1143 Bq kg^?1 in dry weight. The results of the elemental analyses showed potassium, calcium, titanium, iron, tin, and barium in different concentrations.     

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

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

Kinetics and mechanism for the oxidation of anilines by ClO2: a combined experimental and computational study

The oxidation of para‐substituted anilines (X–C₆H₄NH₂, X = –CH₃, –H, –Cl, –NO₂) with chlorine dioxide was studied as a means of eliminating these pollutants. The oxidation rate decreases from that for 4‐methylaniline to that for 4‐nitroanilinem in agreement with the Hammett plot; the oxidation kinetics is second order in aniline and first order in ClO₂, for which a possible mechanism is proposed. Liquid chromatography and gas chromatography mass spectrometry results show that benzoquinone is formed as the major intermediate in aniline/ClO₂ oxidation, and the reaction is pH‐dependent as the rate constant increases with increasing pH. To further support our proposed mechanism, Density Functional Theory (DFT) computations at both B3LYP/6‐311 + G(d,p) level with the polarizable continuum model with an integral equation formalism solvation model (i.e., with water) were carried out, showing that activation energy barriers predict the same reactivity trend as shown by the kinetics experiments. Copyright © 2014 John Wiley & Sons, Ltd.     

三维荧光光谱结合组合算法在环境污染监测中的应用:油种鉴别与定量分析

针对油类污染物成分复杂,光谱重叠难以识别的问题,提出采用三维荧光光谱结合组合算法对油类污染物进行了定性和定量分析。荧光光谱中存在的瑞利散射对三维荧光光谱检测有较大影响,提出了缺损数据修复-主成分分析（MDR-PCA）方法对矿物油三维荧光光谱的瑞利散射进行处理,原理是单个荧光光谱激发发射矩阵符合双线性,可用主成分分析（PCA）法来解析。MDR-PCA法首先将荧光数据中的散射干扰数据全部扣除,之后利用主成分分析（PCA）迭代过程对扣除数据进行重构修复后补全数据。该方法在消除散射干扰的同时充分利用了荧光物质光谱矩阵中的有效信息。利用不同浓度的矿物油的激发-发射荧光光谱构建了三维数据。样品数据来源于柴油、汽油和煤油三种溶质的四氯化碳溶液。常用于三维荧光光谱数据分析的三线性分解算法有平行因子分析（PARAFAC）、交替三线性分解（ATLD）和自加权交替三线性分解算法（SWATLD）等。PARAFAC基于严格意义上的最小二乘原则,具有抗噪声强、模型稳定、微小预期误差等优点,可以实现三维数据阵列的最佳拟合,但该算法收敛速度较慢,对组分数敏感。ATLD算法通过提取对角主元和切尾奇异值求解广义逆,极大提高了收敛速度并降低了对组分数的敏感度,从而实现三线性分解。然而,取对角元时易使ATLD方法对噪声敏感。SWATLD算法既继承了对组分数不敏感、收敛速度快等优点,又降低了噪声水平的影响。但是在抗共线程度方面,SWATLD算法在抵抗共线性程度方面的能力较ATLD略有降低。基于此,论文根据三线性分解算法迭代过程中损失函数的变化,对迭代过程进行划分,提出了三线性迭代方法的组合算法（algorithm combination methodology, ACM）—将ATLD, SWATLD与PARAFAC组合在一起,充分发挥各算法的优点,实现二阶校正算法的优势互补。采用ACM算法对两组分及三组分矿物油样品的三维荧光光谱数据进行解析,并对三种矿物油的回收率进行了计算。柴油的回收率为97.08%,汽油的回收率为97.34%,煤油的回收率为97.25%。解析光谱和回收率表明,ACM算法能够实现油类污染物的种类识别及浓度测量。     

Parameter motivated mutual correlation analysis: Application to the study of currency exchange rates based on intermittency parameter and Hurst exponent

We present a novel method for the parameter oriented analysis of mutual correlation between independent time series or between equivalent structures such as ordered data sets. The proposed method is based on the sliding window technique, defines a new type of correlation measure and can be applied to time series from all domains of science and technology, experimental or simulated. A specific parameter that can characterize the time series is computed for each window and a cross correlation analysis is carried out on the set of values obtained for the time series under investigation. We apply this method to the study of some currency daily exchange rates from the point of view of the Hurst exponent and the intermittency parameter. Interesting correlation relationships are revealed and a tentative crisis prediction is presented.     

Human and climate impact on 15N natural abundance of plants and soils in high-mountain ecosystems: a short review and two examples from the Eastern Pamirs and Mt. Kilimanjaro

Population pressure increasingly endangers high-mountain ecosystems such as the pastures in the Eastern Pamirs and the mountain forests on Mt. Kilimanjaro. At the same time, these ecosystems constitute the economic basis for millions of people living there. In our study, we, therefore, aimed at characterising the land-use effects on soil degradation and N-cycling by determining the natural abundance of ¹⁵N. A short review displays that δ¹⁵N of plant–soil systems may often serve as an integrated indicator of N-cycles with more positive δ¹⁵N values pointing towards N-losses. Results for the high-mountain pastures in the Eastern Pamirs show that intensively grazed pastures are significantly enriched in ¹⁵N compared to the less-exploited pastures by 3.5 ‰, on average. This can be attributed to soil organic matter degradation, volatile nitrogen losses, nitrogen leaching and a general opening of the N-cycle. Similarly, the intensively degraded savanna soils, the cultivated soils and the soils under disturbed forests on the foothill of Mt. Kilimanjaro reveal very positive δ¹⁵N values around 6.5 ‰. In contrast, the undisturbed forest soils in the montane zone are more depleted in ¹⁵N, indicating that here the N-cycle is relatively closed. However, significantly higher δ¹⁵N values characterise the upper montane forest zone at the transition to the subalpine zone. We suggest that this reflects N-losses by the recently monitored and climate change and antropogenically induced increasing fire frequency pushing the upper montane rainforest boundary rapidly downhill. Overall, we conclude that the analysis of the ¹⁵N natural abundance in high-mountain ecosystems is a purposeful tool for detecting land-use- or climate change-induced soil degradation and N-cycle opening.