Speciation and Migration Behavior of Pu and Am in Floodplain Soils and Bottom Sediments of the Yenisei River

Am and Pu speciation in floodplain soils and bottom sediments of the Yenisei River is studied. Pu is more tightly associated with amorphous hydroxides as compared to Am. Am associated with organic matter is potentially more mobile than Pu. Model experiments showed that fulvic acids decelerate Am sorption from water to floodplain soil.     

Speciation of artificial radionuclides 60Co, 137Cs, 152Eu, and 241Am in bottom sediments of the Yenisei river

The speciation of artificial radionuclides ⁶⁰Co, ¹³⁷Cs, ¹⁵²Eu, and ²⁴¹Am in surface layers of bottom sediments of the Yenisei river, collected within the near zone of impact of the Mining and Chemical Combine (Rosatom), was studied. In these samples the radionuclides ⁶⁰Co, ¹⁵²Eu, and ²⁴¹Am are mainly associated with fractions of humic and fulvic acids. The fraction of ¹⁵²Eu associated with nonsilicate iron is approximately 92%. The migration capability of radionuclides collected near the Atamanovo settlement decreases in the order ¹⁵²Eu > ²⁴¹Am > ⁶⁰Co > ¹³⁷Cs. For samples collected near Bol’shoi Balchug settlement, this order is as follows: ¹⁵²Eu ≈ ²⁴¹Am > ⁶⁰Co > ¹³⁷Cs. The presence of radionuclide-bearing micro-particles in bottom sediments considerably complicates the distribution of radionuclides, in particular, of ²⁴¹Am and ¹³⁷Cs, among migration forms.     

Model Study of Migration Behavior in Floods of 241Am and 152Eu Associated with Humus Compounds in Floodplain Soils of the Yenisei River

It is demonstrated in model experiments that in the presence of Ca ions (typomorphous cations of water of the Yenisei River) fulvic acids of floodplain soils and associated radionuclides (Am, Eu) form poorly soluble mixed Ca, Fe, Al(Am, Eu) fulvates. As a result, under the flooding conditions the migration of Am and Eu in the form of solubilized organomineral complexes is practically totally suppressed. With decreasing pH in the model system from 8 to 6 the mobility of the radionuclides noticeably increases.     

Distribution of artificial radionuclides in lacustrine sediments in China

Establishing accurate historical records of the distribution, inventory and source of artificial radionuclides in the environment is important for environmental monitoring and radiological health protection due to their potential toxicity, and is also useful for identification and risk assessment of possible future environmental inputs of radionuclides from nuclear weapons tests and accidental release from the nuclear fuel reprocessing facilities or nuclear power reactors. A sector-field inductively coupled plasma mass spectrometer was used to study the recent sedimentation of Pu isotopes in 11 lakes in China. The distribution of (137)Cs was investigated using the conventional radiometric analytical methods. Based on the isotopic compositions of Pu and the activity ratio of (137)Cs/(239+240)Pu, the sources of artificial radionuclides were identified. The potential applications of Pu isotopes for sediment dating and for regional and global environmental change studies were discussed.     

Hot Particles of the Second Kind in Flood Lands of the Yenisei River

Specific modification of hot particles found in flood-land soils of the Yenisei River was studied. In contrast to the known hot particles (hot particles of the first kind), newly found hot particles are referred to as hot particles of the second kind. Abundance, radionuclide composition, and other characteristics of hot particles of the first and second kinds are compared.     

Dynamics of radiostrontium leaching from radioactively contaminated floodplain soils of the Yenisei River

Gleyzation-mediated leaching of radiostrontium from floodplain soils of the Krasnoyarsk Mining and Chemical Combine (MCC) activity zone [Atamanovskii Island (front part), Oseredysh Island (front part), and Berezovyi Island (rear part)] is studied with model systems. Leaching of radiostrontium from waterlogged soils is analyzed in terms of the model of anaerobic biosolubilization of gel films. The leaching of radiostrontium is found to correlate with that of iron, confirming the cosolubilization model. Addition of glucose (0.5%) as a stimulant for growth of iron-reducing microorganisms increases the dynamic coefficient of radiostrontium leaching, particularly in soils with lower organic matter content. The model experiments showed that the radiostrontium leaching rate from floodplain soil is higher by 2–3 orders of magnitude than that of radio-cesium, suggesting the possibility of escape of radiostrontium from the floodplain of the Yenisei River with the intrasoil runoff. This conclusion is supported by the experimental data on the ⁹⁰Sr/¹³⁷Cs ratio in the floodplain of the Yenisei River downstream of MCC (0.01–0.1).     

PAC在人工流产术后计划生育关爱中的应用

文本研究人流后关爱(PAC)在人工流产术后计划生育关爱中的应用。选择2011年1月—2013年1月,武汉市蔡甸区计划生育服务站门诊进行人工流产的260名病例为分析对象,根据其先后序号按照奇偶顺序分为关爱PAC组和对照组,每组130例,对PAC组进行流产后关爱指导,而对照组只进行常规处理。一年后,共收回有效问卷248份,其中关爱组126份,对照组122份。PAC组避孕知识和人流后保健知识掌握优良率均高于对照组,生活质量评分有明显优势,而重复流产率明显较低,育龄妇女满意率较高。其差异均有统计学意义(P0.05)。高价值的PAC关爱,对于减少重复流产的概率和提高生活质量有着积极重要的意义。     

Prediction of Migration of Radionuclides in the Iput River Basin

Based on the multichamber model, prediction evaluations of the transfer of ¹³⁷Cs and ⁹⁰Sr in the Iput river for 100 years after the Chernobyl accident have been performed. In the course of investigation, the indicated time range was subdivided into three periods: the first period covered April–December of 1986 (retrospective evaluation), the second period embraced the years 1987–2000, and the third period covered the years 2000–2080 (long-term prediction). The prediction evaluations of migration of radioactive contaminants in the Iput river have shown that over the course of a century the concentrations of ¹³⁷Cs in the Iput river network will decrease nearly 3000 times and the concentrations of ⁹⁰Sr will decrease 10,000 times. However the levels of contamination of the river systems by these radionuclides will remain rather high.     

Activity concentrations of natural radionuclides in the sediments of Ogun River, Southwestern Nigeria

The concentrations of naturally occurring radionuclides in the sediments of the Ogun River in Southwestern Nigeria were measured using NaI(Tl) gamma-ray spectrometry. The measurements were made in an effort to better understand the spatial distribution of natural radioactivity and to form a database of radioactivity levels of the Ogun River. The total average activity concentrations of (40)K, (226)Ra and (232)Th in the sediment samples representing the whole Ogun River from the upper region through the middle to the lower region of the river were 499.476±59.167, 12.649±3.476 and 11.774±5.126, respectively. The range of the activity concentrations of (40)K, (226)Ra and (232)Th for the Ogun River were found to be from 370.969±19.261 (at Olopade) to 608.023±24.658 (at Owere), 5.567±2.359 (at Ekerin) to 20.395±4.516 (at Sokori) and 5.037±2.244 (at Mile 12-Maidan) to 23.096±4.806 (at Sokori). The values obtained were compared with internationally accepted values. No man-made radionuclides were detected at any of the locations.     

氧化石墨烯及其复合材料对水中放射性核素的吸附

在核能和核技术的快速发展过程及应用中产生了大量放射性废水,其对生态环境会造成潜在的污染,因此对放射性废水处理技术的研究对保护环境有着重要的意义。氧化石墨烯及其复合材料具有比表面积高、官能团丰富、吸附能力强、化学稳定性好等优点,在放射性废水处理领域受到广泛关注。本文综述了近年来有关氧化石墨烯及其复合材料对水中放射性核素吸附的研究现状及进展,介绍了氧化石墨烯及其复合材料对放射性核素的吸附容量、吸附等温模型、吸附热力学、影响因素和吸附机理。最后分析了氧化石墨烯及其复合材料处理放射性核素在辐射稳定性和高吸附选择性等方面面临的问题和挑战,探讨了推动该类材料今后实际放射性废水处理中工程应用的重点研究方向,如完善的产业体系和积极研发相匹配的成套水处理工艺及设备等。     

Model of Migration of Radionuclides in a River System

The authors suggest a model of transfer of radionuclides in a river system, which relies on the principle of the chamber model, for the case of hydraulically stationary and chemically equilibrium conditions of interaction of radionuclides in the systems water–suspensions and water–bottom sediments. The model is based on analytical solutions of a system of equations for different conditions of ingress of radioactive contaminants into the river system: in the inlet cross section; with fallout of radiactive aerosols on the water surface; with ingress of radionuclides with surface flow from a contaminated water catchment. The model is verified using the data of radiation monitoring carried out on an experimental water catchment of the Iput river.     

Chronology of Radioactive Contamination of Floodland and Bottom Sediments of the Yenisei River Determined from Europium Isotope Ratio

The distribution of ¹⁵²Eu, ¹⁵⁴Eu, and ¹⁵⁵Eu isotopes along the vertical profiles of several floodland and bottom sediments of the Yenisei River was studied. The decrease of ¹⁵⁴Eu/¹⁵²Eu and ¹⁵⁵Eu/¹⁵²Eu ratios down the profiles is described by exponential function. This makes it possible to determine the age of floodland and bottom sediments of the Yenisei River and calculate their average formation rate.     

Improved analysis of dissolved carbohydrates in stream water with HPLC-PAD

This paper describes improvements made to the determination of dissolved carbohydrates in stream water with high-performance liquid chromatography and pulsed amperometric detection (HPLC-PAD). We eliminated interference from dissolved oxygen, separated xylose and mannose along with other molecules, reduced the chromatographic peak shift associated with carbonate accumulation in the column to less than 1% for all samples, and achieved an 8% increase in recovery of hydrolyzed carbohydrates by replacing ion-exchange desalting cartridges with evaporative removal of HCl under N2. These modifications lowered detection limits to less than or equal to 0.4 nM for 10 different monosaccharides and enhanced our ability to follow the dynamics of these molecules in stream ecosystems. In the determination of dissolved free monosaccharides, average relative precision was 1.3% and recovery ranged from 92 to 109%. For dissolved total saccharides, average relative precision was 3.3%. Concentrations were stable when filtered (0.2 microm) stream water was stored for 1 day at 22 degrees C, 1 week at 4 degrees C, or 1.5 months at -20 degrees C.     

Natural radionuclides in borehole water in Port Harcourt, Rivers State, Nigeria

Water samples from boreholes collected from 29 locations in two local government areas in Port Harcourt, Rivers State, Nigeria have been analysed for their natural radioactivity content using a well-calibrated, shielded and highly efficient NaI(Tl) detector based gamma ray with a view to provide baseline data on the radioactivity level in the area, as well as an estimate of the resulting dose on the inhabitants. The radionuclides observed with reliable regularity belonged to the decay series chain headed by (238)U and (232)Th as well as the non-series (40)K. The mean specific activity concentrations of these, are 3.51 +/- 1.22, 2.04 +/- 0.29 and 23.03 +/- 4.37 Bq l(-1), respectively. The respective corresponding estimated mean annual effective dose are 0.36 +/- 0.12, 0.51 +/- 0.07 and 0.05 +/- 0.01, respectively mSv y(-1). These results are relatively high but are still below the recommended limit of 1 mSv y(-1) due to borehole water only. This study is the first in the area and can usefully be associated with similar surveys in other matrices in the area. Meanwhile, the radionuclides detected in the water samples do not seem to pose any radiological consequence on the sample population.     

Thermal diffusion in a turbulent water stream with gas bubbles

Results are shown of an experimental study concerning the heat transfer and the average temperature fields man effervescentgas-liquid stream. It is noted that an increase in the gas content brings about turbulent diffusion of heat across the entire stream section.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 24, No. 5, pp. 781–789, May, 1973.     

Linear theory of water waves on a running stream

Summary We consider the motion of an inviscid, incompressible fluid with surface tensionT, in an infinite channel of finite depth, when a pressure disturbance is imposed on the uniform stream. The explicit solution of the resulting initial value problem is presented. Also, possible steady state flows are discussed. In the cases when they exist, corresponding radiation conditions are found.     

Primary-to-secondary leak monitoring using information obtained from measurement of reference radionuclides in NPP water

Detection of heat-exchange equipment failures in the primary circuit is one of the problems to be solved by radiochemical monitoring during operation of nuclear power installations. A series of experimental and numerical studies were performed in a low-power installation with a water-cooled water-moderated reactor where sequential failure of heat exchangers in two reactor water cleanup and cooling units occurred and progressed. The mechanism of transport of radionuclide impurities from the primary to secondary circuits was determined, and data for different radionuclides were obtained to compare how valuable each radionuclide was as information source for leak detection and monitoring.     

Assessment of doses to the offspring of the Techa River cohort due to intakes of radionuclides by the mother

The Techa River was contaminated as a result of radioactive releases by the Mayak plutonium production facility in 1949-1956. The residents of riverside communities were exposed to internal irradiation from radionuclides ingested mainly with river water, and also to external gamma irradiation resulting from shoreline and flood-plain contamination. The most important role in population exposure was played by (89,90)Sr and 137Cs. The persons born after the onset of the contamination have been identified as the 'Techa River Offspring Cohort' (TROC). The TROC has the potential to provide direct data on health effects in progeny that resulted from exposure of a general population to chronic radiation. This report describes the results of the calculation of fetal doses due to intakes of radionuclides by their mothers. Particular attention has been given to fetal dose from 90Sr because this nuclide is the most significant in terms of population dose for the Techa River. The comparison of the fetal bone marrow doses evaluated using different approaches proposed in the literature has shown a large dispersal in dose values. The main cause of this is the difference in model assumptions simplifying some developmental aspects of fetal haematopoiesis and bone formation. This paper presents an analysis of these basic assumptions that could be useful for further improvements in fetal dosimetry.     

用超滤膜处理长江水

采用混凝-砂滤-超滤膜的联用工艺对长江原水进行了中试研究,结果表明,混凝一砂滤作为预处理能有效地去除大分子的有机物．5个月的试验中,膜压差增长缓慢,实现了长期稳定运行．出水的浊度、CODMn和DOC的平均值分别为0．068NTU,1．23mg／L和1．3mg/L。