聚糖原菌富集实验及其内源过程探究

细胞衰减是微生物内源过程的一个重要组成部分,可分为由细胞死亡引起的数量衰减和由细胞活性降低引起的活性衰减两部分.通过挥发性脂肪酸（VFA）吸收速率(VFAUR)测定、荧光原位杂交技术（FISH）以及LIVE/DEAD细胞染色技术,研究了富集聚糖原菌（GAOs）在序批式反应器（SBR）系统中好氧环境下的衰减特征.结果表明,当T=30℃、进料中m(COD)∶m(P)=100时,SBR系统中GAOs富集比例达94%.测定和计算表明,SBR富集系统中GAOs衰减速率和死亡速率分别为0.132 d^-1和0.034 d^-1,其数量衰减和活性衰减占其细胞总衰减比例分别为26%和74%.可见,GAOs数量衰减只占其细胞总衰减中很小一部分,而绝大部分衰减由活性衰减所引起.     

放射性核素大气扩散数值模拟研究综述

放射性核素大气扩散模式可以模拟放射性核素在不同尺度下的大气输送与扩散,为核电站选址、核事故应急提供科学依据.本文总结了目前广泛用于模拟核素扩散的多种模式,详细比较了各模式对放射性核素的衰变、输送和扩散、干/湿沉降和重力沉降以及辐射剂量等处理方法,总结归纳各个模式模拟的差异性.最后,对放射性核素大气扩散模式发展前景做了展望.对有针对性地提高模式模拟能力以及明确模式的发展方向具有重要的意义.     

新疆某伴生放射性钒矿氡浓度水平调查及防治措施的探讨

在伴生矿的勘探、开采过程中,如果井下工作场所通风不足,矿石、土壤和岩石等所释放的氡气会造成局部的放射性污染,因此了解伴生矿矿井中氡气的水平并探讨有效的防护措施是非常必要的。本文就新疆某矾矿在矿井建设初期和通风设施建成后两时间段的氡浓度水平及防治措施进行探讨,并提出相应的防护措施和建议。     

放射性废物管理的国际法制度——《乏燃料管理安全和放射性废物管理安全联合公约》的视角

放射性废物管理是当今世界面临的一个重要问题。本文试图从国际法的角度，联系可持续发展理论，对迄今为止有关放射性废物管理方面最重要的全球性公约——《乏燃料管理安全和放射性废物管理安全联合公约》进行介绍和分析，并在此基础上就完善国际放射性废物管理法律制度提出建议。     

稀土农用对环境的影响

稀土在我国工业、农业应用中已有几十年的历史,人们对稀土在农作物上的增长作用及机理已逐渐了解,其在农用上的应用也越来越广泛,对环境的影响亦逐渐引起人们的关注。文章从稀土元素在环境中的含量、毒性特点、辐射水平、残留量等方面分析讨论了稀土农用对环境的影响。现有研究结果表明:稀土微肥在现行施用量的条件下,对人体健康是安全的,不会对环境、水体、农田生态环境造成污染。     

Heavy metals and arsenic fixation into freshwater organic matter under Gammarus pulex L. influence

Organic sediments are a main sink for metal pollutants in aquatic systems. However, factors that make sediments a sink of metals and metalloids are still not clear. Consequently, we investigate the role of invertebrate shredders (Gammarus pulex L.) on quality of metal and arsenic fixation into organic partitions of sediment in the course of litter decay with laboratory microcosm experiments. During the decomposition of leaf litter, G. pulex significantly facilitated the development of small particles of organic matter. The capacity of metal fixation was significantly higher in smaller particles than leaf litter and litter residuals. Thus, G. pulex enhanced metal fixation into the organic partition of sediments by virtue of increasing the amount smaller particles in the aquatic system. Furthermore, invertebrates have a significant effect on formation of dissolved organic matter and remobilization of cobalt, molybdenum and cesium, but no significant effect on remobilization of all other measured elements.     

混凝-吸附处理黄河水及对氯消毒中氯衰减的影响

选用2种无机高分子混凝剂聚合氯化铁(PFC)和聚合氯化铝(PAC)处理黄河水,考察了混凝剂的投加量对浊度、UV254、DOC和高锰酸盐指数的去除效果,并结合混凝出水的Zeta电位分析其混凝机制.选择粉末活性炭与混凝联用,研究了混凝剂和吸附剂投加量以及二者的投加顺序对有机物去除效果的影响,并对混凝吸附后出水进行加氯消毒,考察水中残余氯随时间的变化.结果表明,2种混凝剂均有较高的浊度去除率(﹥90%).PAC对UV254、高锰酸盐指数和DOC的去除率分别为29.2%、26.1%和27.9%;PFC对三者的去除率分别为32.3%、23.3%和32.9%.PAC在混凝过程中,电中和作用占主导地位;PFC在混凝过程中,吸附架桥和电中和同时发挥作用.混凝-吸附联用处理黄河水样时,有机物的去除率随混凝剂和吸附剂投加量的增加而升高.先混凝后吸附工艺对UV254和DOC的去除效果优于先吸附后混凝工艺.先使用PAC混凝后吸附对UV254和DOC的去除率分别为95.2%和99.9%;对于PFC,先混凝后吸附对UV254和DOC的去除率分别为90.1%和99.9%.但是先投加粉末活性炭能提高矾花的沉降性能,且处理出水在保持持续消毒效果方面优于前者.     

Fast method for simulation of radionuclide chain migration in dual porosity fracture rocks

In fractured rocks with a porous rock matrix such as granites, radionuclides will flow with the water in the fracture network. The nuclides will diffuse in and out the rock matrix where they can sorb and be considerably retarded compared to the water velocity. A water parcel entering the network will mix and split at the fracture intersections and parts of the original parcel will traverse a multitude of different fractures. The flowrates, velocities, sizes and apertures of the fractures can vary widely. Normally one must solve the transport equations for every fracture and use the effluent concentration as inlet condition to the next fracture and so on. It is shown that under some weakly simplified conditions it suffices to determine one single parameter group containing information on the flow wetted surface that a water parcel contacts along the entire path. It is also shown how this can be obtained. Then, solving the transport equations only once for time and location along the path gives the concentration and nuclide flux of every nuclide in the chain everywhere along a path. The same solution actually is valid for every path in the network. This dramatically reduces the computation effort. The same approach can be used for models based on streamtubes.     

Concentrations of long-lived artificial radionuclides in the moss-lichen cover of mountain plant communities

Specific features of⁹⁰Sr and¹³⁷Cs accumulation in individual lichen species and in the moss-lichen cover of plant communities were studied in some mountain ranges of the Polar and Northern Urals. The results showed that the amounts of radionuclides in lichens and mosses of mountain plant communities are at the level characteristic of the moss-lichen cover of flat ecosystems, and their accumulation depends on⁹⁰Sr and¹³⁷Cs input with the global radioactive fallout. The radionuclide contents in lichens and mosses sampled from different mountain rocks, slopes, and elevations fluctuate around this level. The differences depend both on the structural and functional properties of plants and on the climatic and ecological features of their environment.     

THE NEED FOR A COMPREHENSIVE APPROACH IN THE MANAGEMENT OF ENVIRONMENTAL RESOURCES1

ABSTRACT Environmental resources can be managed properly only by adopting a comprehensive approach. The whole environment must be considered as a single system, and prior to any action, all types of environmental impacts caused by it should be studied in detail. This paper underlines the close relationship between different environmental problems, analyzes existing management patterns, and proposes new alternatives whenever applicable. The different constraints, which have to be considered in the decision-making process while developing a plan, are also discussed. It is concluded that efforts neglecting the interaction among different aspects of the environment do not upgrade the quality of water, air, and land to any appreciable degree.