Synthesis and evaluation of a thiourea-modified chitosan derivative applied for adsorption of Hg(II) from synthetic wastewater

In this work, a thiourea-modified chitosan derivative (TMCD) was synthesized through two steps, O-carboxymethylated first and then modified by a polymeric Schiff's base of thiourea/glutaraldehyde. The adsorption behavior of mercury (II) ions onto TMCD was investigated through batch method. The maximum adsorption capacity for Hg(II) was found to be 6.29 mmol/g at pH 5.0 and both kinetic and thermodynamic parameters of the adsorption process were obtained. The results indicated that adsorption process was spontaneous exothermic reaction and kinetically followed pseudo-second-order model. The adsorption experiments also demonstrated TMCD had high adsorption selectivity towards Hg(II) ions when coexisted with Cu(II), Zn(II), Cd(II) and Ca(II) in solution and it could be easily regenerated and efficiently reused. (C) 2010 Elsevier B.V. All rights reserved.

Selective and specific detection of sulfate-reducing bacteria using potentiometric stripping analysis

A fast, sensitive and reliable potentiometric stripping analysis (PSA) is described for the selective detection of the marine pathogenic sulfate-reducing bacterium (SRB). Desulforibrio caledoiensis. The chemical and electrochemical parameters that exert influence on the deposition and stripping of lead ion, such as deposition potential, deposition time and pH value were carefully studied. The concentration of SRB was determined in acetate buffer solution (pH 5.2) under the optimized condition (deposition potential of -1.3 V. deposition time of 250 s, ionic strength of 0.2 mol L-1 and oxidant mercury (II) concentration of 40 mg L-1). A linear relationship between the stripping response and the logarithm of the bacterial concentration was observed in the range of 2.3 x 10 to 2.3 x 10(7) cfu mL(-1). In addition, the potentiometric stripping technique gave a distinct response to the SRB, but had no obvious response to Escherichia coli. The measurement system has a potential for further applications and provides a facile and sample method for detection of pathogenic bacteria. (C) 2010 Elsevier B.V. All rights reserved.

Livestock grazing, plateau pikas and the conservation of avian biodiversity on the Tibetan plateau

On the Qinghai-Tibet plateau increased livestock numbers have resulted in degradation of the grasslands with potential impacts on native biodiversity. Concurrently, perceived increases in populations of native small mammals such as plateau pikas (Ochotona curzoniae) have led to poisoning programs, with uncertain impacts on species such as ground-nesting birds. We explored the relationships between the local seasonal abundance of small birds and (1) the density of pika burrows; (2) livestock grazing practices; and (3) local poisoning of pikas. Around Naqu prefecture, central Tibet, we used a nested experimental design to collect data from areas rested from grazing over summer, nearby areas with year-round grazing and areas subjected to pika poisoning. Additional data were collected from a site where grazing had not occurred for at least 4 years prior to the study. Poisoning pikas in spring had no detectable effect on the local abundance of birds the following autumn. However, two ground-nesting species, white-rumped and rufous-necked snowfinches, showed positive associations with the density of pika burrows, indicating that long-term 'pika poisoning could reduce the density of these species by reducing the density of pika burrows. Rufous-necked snowfinches and non ground-nesting species including horned larks and common hoopoes showed positive responses to reduced grazing pressure from livestock, particularly in the long-rested site, indicating current grazing levels could be having a negative impact on these species. Conservation of small passerine biodiversity in this system will require changed management practices for livestock and pikas that consider the complex three-way interaction between livestock grazing, pikas and small birds. (C) 2008 Elsevier Ltd. All rights reserved.

Analysis of diets of upland buzzards using stable carbon and nitrogen isotopes

We measured the stable carbon and nitrogen isotope ratios for muscles of the upland buzzards (Buteo hemilasius) and their potential food sources, plateau pikas (Ochotona curzoniae), Qinghai voles (Lasiopodomys fuscus), plateau zokors (Myospalax fontanierii), and several passerine bird species at the alpine meadow in Maduo county, Guoluo prefecture of Qinghai province, People's Republic of China, to provide diet information of upland buzzards, highlighting different diet composition of upland buzzards exposed to different locations. The results demonstrated that stable carbon isotope ratios of upland buzzards, passerine birds, plateau pikas, plateau zokors, and Qinghai voles were -24.42 +/- 0.25parts per thousand, -22.89 +/- 1.48parts per thousand, -25.30 +/- 1.47parts per thousand, -25.78 +/- 0.22parts per thousand, and -25.41 +/- 0.01parts per thousand, respectively, and stable nitrogen isotope ratios were 7.89 +/- 0.38parts per thousand, 8.37 +/- 2.05parts per thousand, 5.83 +/- 1.10parts per thousand, 5.23 +/- 0.34parts per thousand, and 8.86 +/- 0.06parts per thousand, respectively. Fractionation of stable carbon and nitrogen isotope ratios between upland buzzards and their food were 1.03parts per thousand and 2.11parts per thousand, respectively. Based on mass balance principle of stable isotopes and the Euclidean distance mixing model, upland buzzards depended mainly on plateau pikas as food (74.56%). Plateau zokors, Qinghai voles, and passerine birds only contributed a small proportion (25.44%) to diets of upland buzzards. The results were closely accordant with analyses of stomach contents and food pellets, which firmly supported the feasibility of using stable carbon and nitrogen isotope ratios to investigate diet information of upland buzzards. Another study based on stable carbon isotopes showed that upland buzzards living in the Haibei prefecture (another prefecture located in the southeast Qinghai province) mainly preyed on passerine birds (64.96% or more) as food supply. We were alarmed by the preliminary results that widespread poisoning activities of small mammals could reshape the food composition of upland buzzards, influencing the stability and sustainability of the alpine meadow. Bio-control on rodent pests should be carried out rather than the chemical measures.

Burrowing rodents as ecosystem engineers: the ecology and management of plateau zokors Myospalax fontanierii in alpine meadow ecosystems on the Tibetan Plateau

1. Plateau zokors, Myospalax fontanierii, are the only subterranean herbivores on the Tibetan plateau of China. Although the population biology of plateau zokors has been studied for many years, the interactions between zokors and plants, especially for the maintenance and structure of ecological communities, have been poorly recognized. In the past, plateau zokors have been traditionally viewed as pests, competitors with cattle, and agents of soil erosion, thus eradication programmes have been carried out by local governments and farmers. Zokors are also widely and heavily exploited for their use in traditional Chinese medicine.2. Like other fossorial animals, such as pocket gophers Geomys spp. and prairie dogs Cynomys spp. in similar ecosystems, zokors may act to increase local environmental heterogeneity at the landscape level, aid in the formation, aeration and mixing of soil, and enhance infiltration of water into the soil thus curtailing erosion. The changes that zokors cause in the physical environment, vegetation and soil clearly affect the herbivore food web. Equally, plateau zokors also provide a significant food source for many avian and mammalian predators on the plateau. Zokor control leading to depletion of prey and secondary poisoning may therefore present problems for populations of numerous other animals.3. We highlight the important role plateau zokors play in the Tibetan plateau ecosystem. Plateau zokors should be managed in concert with other comprehensive rangeland treatments to ensure the ecological equilibrium and preservation of native biodiversity, as well as the long-term sustainable use of pastureland by domestic livestock.

三塘湖盆地牛圈湖区储层特征研究—以齐古组、头屯河组为例

In view of few researches into pore textures and anisotropy characteristics of Qiguzu-toutunhezu reservoir in Niuquanhu block in Santanghu Basin, in order to enhance the hydrocarbon recovery of the region of interest and improve the reservoir development effect, with the employment of the experiments like cast thin slice, scanning electron microscope, conventional high pressure mercury penetration, constant speed mercury penetration and nuclear magnetic resonance, the thesis makes a thorough research into pore texture characteristics and anisotropy characteristics of the sandstone reservoir. The research shows that the microscopic pore textures are complicated, the anisotropy is high and waterflood development water/oil displacement efficiency is low, which are mainly caused by the high microscopic anisotropy of the reservoir. Specially, the research shows that Qiguzu-toutunhezu reservoir belongs to braided delta front intrafacies, the intergranular pore is the main type of pores, which take up 65.50 percent of total pores, intergranular dissolved pores, feldspar dissolved pores and lithic dissolved pores are on the second place, and there are few carbonate dissolved pores. The reservoir belongs to mesopore-fine throat and mesopore-medium throat. The pore distribution of the sandstone reservoir is comparatively centralized. The reservoir inhomogeneity is mainly caused by the throat inhomogeneity. Diagenesis mainly includes compaction, cementation, metasomatism and dissolution. Compared with compaction， cementation exerts more direct impact on the decline of the porosity of the sandstone reservoir ( pore loss factor is 63.75 percent in the cementing process). Based on the classification of diagenetic stages, the reservoir diagenesis is on the stage of the late period of early diagenetic stage to early period of late diagenetic stage. The study area of the small sandstone reservoir layer of the anisotropy of the relatively strong; plane, the anisotropy of the relatively weak. microscopic anisotropy of its relatively strong.

鄂尔多斯盆地志丹地区延长组储层综合评价

Sedimentary provenance direction，sedimentary facies，reservoir geological characteristic，pore structure； physical property characteristic，reservoir classification and evaluation ，forthermore，favorable area area are forecasted of Yanchang formation in ZhiDan region， by mainly study on the data of field section observation ，core observation, well logging explaination and routine microscope slice identification，scanning Electron Microscope and reservoir analysis of lithology and physical property , Under the guidance of such advanced theories and methods as sedimentology，reservoir sedimentology，lithological oil pool and so on，in the thesis. The following fruits are mainly achieved in this paper： Yanchang formation stratum is divided and correlated in this entire region， and the characteristic of oil layer unit is detailed discussed , respectively. According to main marker bed and supplementary ones.and research result shows that the source of provenance direction during Yanchang Formation mianly is north-east. Delta and lake are mainly developed in study area ，sub-facies and micro-facies are divided，distribution of sedimentary micro-facies in plane and palaeogeographic evolution are described，and gentle slope type- shallow water delta depositional model is established. Fine-grain arkose sandstone is the main reservoir，and which have experienced such different degree diagenesis as compaction, cementation, replacement and dissolution, and in which compaction and cementation are mainly factors to reduce sandstone physical property and dissolution effectively improved physical property during burial diagenesis procedure. All reservoirs of Yanchang Formation have entered A period of late diagenetic stage according to scheme of diagenesis period division . Intergranular porosity，dissolution porosity，fissure porosity are main pore types. And porosity structure are analyse by mercury penetration capillary pressure parameter，fine-shortness type and fine- length throat type are mainly developed. as a whole，the reservoir， with the characteristic of porosity and permeability altering apparently，strong inhomogeneity ， is a medium- porosity and medium permeability one. In plane，higher- porosity and higher-permeability are corresponded well with distributary channel area， physical property and inhomogeneity are affected by both deposition and diagenesis，and distributary channel and underwater distributary channel are favorable facies . According to such characteristic as lithology，physical property，pore structure ，diagenesis and sandstone distribution, the sandy reservoir can be classified 4 types, and the main sandy in every oil layer unit are evaluated according to the standard. The analysis result of petroleum concentration rule shows that Yanchang Formation are with not only favourable oil source rock，reservoir，covering combination ，but also good entrapment condition in study area. Lithology and structure-lithology oil pool are mainly developed ，based on condition of favorable reservoir developments，accounting for deliverability and sandstone superface elevation，zone of profitabilitis are forecasted.

砂砾岩储层流动单元四维模型研究

This article is an important part of "95" technological subject of SINOPEC. It has a large number of difficulties and workloads, and has significant theoretical meanings and practical value. The study area is composed of sandstone & conglomerate reservoir of alluvial fan & fan delta, which belong to Sha3 lower member and Sha4 upper member of lower tertiary of Yong'an Town Oilfield in Dongying Depression. The target stataum develops in the hanging wall of the synsedimentary fault in the scarp zone of Dongying Depression. The frequently intense movements result in the variation of sandstone and conglomerate reservoir and the evolution of the time and space of Sha3 lower member and Sha4 upper member in Yong'an Town Oilfield. As a result, it is difficult for the individual reservoir correlation at the root of fan, which bring about a tackle problem for the exploitation of oilfield. In this background, the research of fluid units will be more difficult. In this article, the new concepts, the new methods, and the new techniques of sedimentology, petroleum geology, reservoir geology, physics of crystal surface, dynamic & static state reservoir description and well logging geology are synthetically applied, and the computer technology are made full uses of, and the identifying, dividing and appraising of the two-formation-type sandstone & conglomerate reservoir fluid units of Sha3 lower member and Sha4 upper member systemically analyzed in Yong'an Town Oilfield, Dongying Depression. For the first time, the single-well model, the section model, the plane model, the nuclear magnetism log model, the microcosmic network model, the 4-D geology model and the simulation model of the two-formation-type reservoir fluid units of the of sandstone & conglomerate reservoir of Sha3 lower member and Sha4 upper member are established, and the formative mechanism and distributing & enrichment laws of oil-gas of the two type of sandstone and conglomerate reservoir fluid units are revealed. This article established the optimizing, identifying, classifying and appraising standard of the two-formation-type reservoir fluid units of the of sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which settles the substantial foundations for static state model of the fluid units, reveals the macroscopic & microcosmic various laws of geometrical static state of the fluid units, and instructs the oil exploitation. This article established static state model of the two-formation-type sandstone and conglomerate reservoir fluid units by using the multi-subject theories, information and techniques, and reveals the geometrical configuration, special distribution and the oil-gas enrichment laws of the sandstone and conglomerate reservoir fluid units. For the first time, we established the nuclear magnetism log model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which reveals not only the character and distributing laws of the porosity and permeability, bat also the formation and distribution of the movable fluid. It established six type of microcosmic net model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member in the working area by using the advanced theories, such as rock thin section, SEM, image analysis, intrusive mercury, mold, rock C.T. measure & test image etc., which reveals the microcosmic characteristic of porosity & throat, filterate mode and microcosmic oil-gas enrichment laws of the sandstone and conglomerate reservoir. For the first time, it sets up the 4-D model and mathematic model of the sandstone and conglomerate reservoir, which reveals the distributing and evolving laws of macroscopic & microcosmic parameters of the two-formation-type sandstone and conglomerate reservoir and oil-gas in 4-D space. At the same time, it also forecasts the oil-gas distribution and instructs the oilfield exploitation. It established reservoir simulation model, which reveals the filterate character and distributing laws of oil-gas in different porosity & throat net models. This article established the assistant theories and techniques for researching, describing, indicating and forecasting the sandstone and conglomerate reservoir fluid units, and develops the theories and techniques of the land faces faulted basin exploitation geology. In instructing oilfield exploitation, it had won the notable economic & social benefits.

准噶尔盆地低阻油藏实验研究及储层评价方法

Low resistivity reservoir is a special reservoir which is different from normal reservoir in identification and evaluation.Through core experiment and analysis, the achievement of which resistivity is resulted from clay additive electric conductivities and high bound water saturation in Junggar basin is gained. For accurately evaluating low resistivity, a good many of experiment have been completed, such as resistivity index and formation factor in hi^jher temperature and higher pressure, semi-permeability board, cation exchange, bound water, NMR (nucleus magnetism response), non-Nad water in different temperature and salinity, the experiments result show that lower resistivity has complex relation with these electric-parameters and chloric ion content in non-NaCl water.Based on comprehensive interpretation of NMR and normal resistivity data, the volume of moved water, bound water, moved oil and residual oil in the strata can be determined quantitatively and which have significant influence on reservoir recognition and perforation optimized.Experiment data (SEM mold, thin section, X ray diffraction, mercury penetration) can be used to analysis low resistivity forming and the relation between low resistivity and pore texture, to set up relation between porosity, permeability and petrophysical property. The reservoir was sorted, evaluated and described. The oil bedding in southern margin of Junggar basin is low porosity, low resistivity reservoir.Based on invasion theory of electric well-logging, modelling and inversion of resistivity well-logging are accomplished. For enhancing low resistivity resulted from higher bound water saturation and cation exchange, invasion period, invasion radius, the relation between fluid distribution in pore and response of laterolog logging have been studied. Virgin zone resistivity, invasion zone resistivity and invasion radius were inversed and which enhanced evaluation accuracy of reservoir. The method was used to process well-logging data in Luliang oilfield and southern margin in Junggar basin, and reservoir resistivity was enhanced effectively, appropriate oil saturation gained and it has better effect on oil exploration.

大港油田孔南地区孔一段储层流动单元研究

The main reservoir type in the south of Dagang Oilfield is alluvial reservoir. In this paper, the reservoir structure model and the distribution of connected body and flow barrier were built on base of the study of high-resolution sequential stratigraphic skeleton and fine sedimentary microfacies on level of single sandbody. Utilizing the static and dynamic data synthetically and carrying out the comparision of the classification method for reservoir flow unit in different reservoir, the criterion, which can be used to classify the flow unit in first section of Kongdian formation of Kongnan area, was defined. The qualitative method of well-to-well correlation and the quantitative method of conditional simulation using multiple data are adopted to disclose the oil and water moving regulation in different flow unit and the distribution rule of remaining oil by physical simulation measure. A set of flow unit study method was formed that is suit for the Dagang Oilfield on account of the remaining oil production according to the flow unit. Several outstanding progresses was obtained in the following aspects:It is considered that the reservoir structure of Zao V iow oil group- Zao Vup4 layerand are jigsaw-puzzled reservoir, while ZaoVup3-ZaoVupi layers are labyrinth reservoir,which are studied on base of high-resolution sequential stratigraphic skeleton on the levelof single sandbody in first section of Kongdian formation of Kongnan area and accordingto the study of fine sedimentary microfacies and fault sealeing.When classifying the flow unit, only permeability is the basic parameter using thestatic and dynamic data and, and also different parameters should be chose or deleted, suchas porosity, effective thickness, fluid viscosity and so on, because of the weak or stronginterlayer heterogeneous and the difference of interlayer crude oil character.The method of building predicting-model of flow unit was proposed. This methodis according to the theories of reservoir sedimentology and high-resolution sequencestratigraphic and adopts the quantitative method of well-to well correlation and the quantitative method of stochastic simulation using integrateddense well data. Finally the 3-D predicting-model of flow unit and the interlay er distribution model in flow unit were built which are for alluvial fan and fan delta fades in first section of Kongdian formation of Kongnan area, and nine genetic model of flow unit of alluvial environment that spread in the space were proposed.(4) Difference of reservoir microscopic pore configuration in various flow units and difference of flow capability and oil displacement effect were demonstrated through the physical experiments such as nuclear magnetic resonance (NMR), constant rate mercury penetration, flow simulation and so on. The distribution of remaining oil in this area was predicted combining the dynamic data and numerical modeling based on the flow unit. Remaining oil production measure was brought up by the clue of flow unit during the medium and late course of the oilfield development.

花岗岩风化土微观结构及其工程地质特性研究

Saprolite is the residual soil resulted from completely weathered or highly weathered granite and with corestones of parent rock. It is widely distributed in Hong Kong. Slope instability usually happens in this layer of residual soil and thus it is very important to study the engineering geological properties of Saprolite. Due to the relic granitic texture, the deformation and strength characteristics of Saprolite are very different from normal residual soils. In order to investigate the effects of the special microstructure on soil deformation and strength, a series of physical, chemical and mechanical tests were conducted on Saprolite at Kowloon, Hong Kong. The tests include chemical analysis, particle size analysis, mineral composition analysis, mercury injection, consolidation test, direct shear test, triaxial shear test, optical analysis, SEM & TEM analysis, and triaxial shear tests under real-time CT monitoring.Based on the testing results, intensity and degree of weathering were classified, factors affecting and controlling the deformation and strength of Saprolite were identified, and the interaction between those factors were analyzed.The major parameters describing soil microstructure were introduced mainly based on optical thin section analysis results. These parameters are of importance and physical meaning to describe particle shape, particle size distribution (PSD), and for numerical modeling of soil microstructure. A few parameters to depict particle geometry were proposed or improved. These parameters can be used to regenerate the particle shape and its distribution. Fractal dimension of particle shape was proposed to describe irregularity of particle shapes and capacity of space filling quantitatively. And the effect of fractal dimension of particle shape on soil strength was analyzed. At the same time, structural coefficient - a combined parameter which can quantify the overall microstructure of rock or soil was introduced to study Saprolite and the results are very positive. The study emphasized on the fractal characteristics of PSD and pore structure by applying fractal theory and method. With the results from thin section analysis and mercury injection, it was shown that at least two fractal dimensions Dfl(DB) and Df2 (Dw), exist for both PSD and pore structure. The reasons and physical meanings behind multi-fractal dimensions were analyzed. The fractal dimensions were used to calculate the formation depth and weathering rate of granite at Kowloon. As practical applications, correlations and mathematical models for fractal dimensions and engineering properties of soil were established. The correlation between fractal dimensions and mechanical properties of soil shows that the internal friction angle is mainly governed by Dfl 9 corresponding to coarse grain components, while the cohesion depends on Df2 , corresponding to fine grain components. The correlations between the fractal dimension, friction angle and cohesion are positive linear.Fractal models of PSD and pore size distribution were derived theoretically. Fragmentation mechanism of grains was also analyzed from the viewpoint of fractal. A simple function was derived to define the theoretical relationship between the water characteristic curve (WCC) and fractal dimension, based on a number of classical WCC models. This relationship provides a new analytical tool and research method for hydraulic properties in porous media and solute transportation. It also endues fractal dimensions with new physical meanings and facilitates applications of fractal dimensions in water retention characteristics, ground water movement, and environmental engineering.Based on the conclusions from the fractal characteristics of Saprolite, size effect on strength was expressed by fractal dimension. This function is in complete agreement with classical Weibull model and a simple function was derived to represent the relationship between them.In this thesis, the phenomenon of multi-fractal dimensions was theoretically analyzed and verified with WCC and saprolite PSD results, it was then concluded that multi-fractal can describe the characteristics of one object more accurately, compared to single fractal dimension. The multi-fractal of saprolite reflects its structural heterogeneity and changeable stress environment during the evolution history.

气候变化对高纬度流域中汞和甲基汞迁移转化的影响——以降水量增加为例

全球变化的研究发现：19世纪以来全球平均气温大约上升了0.6℃，并预计在21世纪会升高更多。温室效应的直接结果是导致全球地面增温，温度的升高会增加下垫面的蒸发量。根据全球水平衡原理，蒸发量应该与降水量相等，因而降水量也会相应增加。气候变化的情景模式研究表明，世界各地雨量变异大，在高纬度地区，包括北欧地区，降水会增加。 流域是水生系统的一个重要的汞和甲基汞的输入源。欧洲淡水系统中，鱼体汞含量过高的湖泊主要局限于北方的高纬度森林地区。在斯堪的纳维亚半岛，就有上万湖泊中的鱼体汞含量超过了健康食用标准0.5 mg/kg。水生系统甲基汞输入源包括：水体或沉积物通过甲基化形成甲基汞，通过大气干、湿沉降输入的甲基汞和陆地生态系统的地表径流输入的甲基汞。 本研究的主要目标是搞清楚未来气候变化引起的大气降水量的增加对北方高纬度森林流域土壤中汞的迁移和形态转化有何影响。未来大气降水量的增加可能会增强森林地区流域土壤中汞的迁移，进而对水生系统的汞循环产生影响。一方面，如果地下水水位上涨，当水流过富含有机质结合含汞土壤层时，将会增加土壤中汞和甲基汞的迁移性，由此而导致流域向河流、湖泊等水生系统中汞输出通量的增加。另一方面，氧化还原电位改变、DOC和营养物质的释放会加剧汞在土壤中的释放过程，并且可能会促进汞的形态转化，可能增加毒性较强的甲基汞的产量，最终导致甲基汞从土壤向水生系统的输出通量的增加。 本研究选择瑞典西海岸花园湖（Gårdsjön）的G1流域作为研究对象，在流域内进行人工模拟增加降雨试验，模拟未来气候变化降水量增加的情景，观测流域地表径流中汞和甲基汞的变化。并在流域内选择四个点（1×1m²），进行汞同位素加入示踪试验。测定土壤剖面甲基汞和总汞及其同位素组成，来分析汞的迁移和形态转化。主要研究结果如下： 1. 通过对G1流域土壤中甲基汞分布的调查，发现甲基汞含量范围为0.020-3.1ng/g，甲基汞含量与TOC含量具有正相关的关系，表明土壤甲基汞的迁移受TOC迁移的影响。估算G1流域的甲基汞储库通量为123g/km2，G1流域甲基汞储库容为0.65g。 2. 通过甲基汞含量和甲基汞储库在土壤剖面的分布，可以看出表层腐殖质层甲基汞浓度最高，甲基汞最富集，而在较深的土壤层位甲基汞储库容量最大，表明甲基汞具有向下迁移的趋势。 3. 根据总汞同位素组成结果，汞同位素（198Hg(NO3)2）加入土壤中后，202Hg/198Hg比值迅速下降，然后随时间推移而上升，表明加入土壤中的汞与土壤中原始汞形态不同，具有不同的迁移方式，且加入土壤中二价汞的迁移性比土壤中的原始汞更强。计算表明，外界加入的汞，将有50-60%长期滞留在土壤中。 4. 根据甲基汞的同位素组成结果，Wet点的新加入的198Hg甲基汞分数要大于其它三点，表明湿润土壤中汞甲基化速率要快于较干燥的土壤中。另外，Wet点的甲基汞分数比以前无人工模拟增加降雨的同位素示踪结果高很多，表明降水量增加会导致汞的甲基化作用在土壤中的形态转化过程中占主导地位，最终导致甲基汞产率的提高。 5. 人工模拟增加降雨试验进行后，地表径流中总汞的浓度没有发生变化，而甲基汞的浓度增大了很多，从0.03ng/L增大到了1ng/L以上，表明降水的增加可以促进土壤中汞的甲基化作用。 6. 地表径流向流域外总汞和甲基汞的输出量的计算显示，受人工模拟增加降雨的影响，流域地表径流量也会增加，最终年地表径流中总汞和甲基汞的输出通量都变大。

贵阳市中心城区大气中不同形态汞的研究

汞，是一种人体非必需的有毒重金属元素，一种全球性污染物，其全球生物地球化学循环演化规律的研究是目前环境科学领域的热点问题。汞在大气中的行为对其全球生物地球化学循环起着极其重要的控制作用。因此，关于大气汞循环演化规律的研究已经成为目前汞全球生物地球化学研究的热点问题。大气中的汞主要分为三类，即气态单质汞（GEM）、活性气态汞（RGM）和颗粒态汞（TPM）。各种形态汞的物理化学性质不同，在大气中的行为存在显著的差异。研究大气中不同形态汞的分布特征，对于正确认识汞在大气中的循环演化规律意义重大。目前中国是全球人为活动向大气释汞最多的国家，而城市区域是人为活动的中心地带，城市大气汞污染形势严峻。因此，开展城市大气中不同形态汞的研究对于评价与预测城市环境汞污染特征以及正确认识大气汞的局地、区域、全球循环演化规律具有重要的理论与实际意义。 本论文选取贵州省省会贵阳市的中心城区作为研究区域。贵阳市（东经106º07´~107º17´，北纬26º11´~27º22´）位于中国西南地区正好处在环太平洋汞矿化带中，能源消耗以煤炭为主，大气环境污染属煤烟型污染，常年影响大气环境质量的主要污染物是二氧化硫和可吸入颗粒物。本论文的研究工作包括：⑴2004年4月～12月在中国科学院地球化学研究所建立与完善了大气中气态总汞（TGM）、GEM、RGM、TPM的采集与分析方法，并测定了大气和雨水中不同形态汞的含量，对大气汞的干、湿沉降通量进行了估算；⑵2005年4月～2006年1月在贵阳市中心城区的居民区、商业区、工业区、游览区4个功能区各设1个研究点，农村设1个对照点，按春、夏、冬3个季节研究了大气中GEM、RGM、TPM的分布特征，估算了贵阳市中心城区大气汞的干沉降通量，并利用高分辨透射电子显微镜（HR–TEM）分析技术对冬季各采样点TPM的来源作了定性识别；⑶测量了中心城区表层土壤和某些植物的总汞（THg）含量，探讨了大气汞对中心城区地表生态系统的污染效应。通过本论文的研究，得出以下主要结论： 1.在国内外研究基础上，建立了金捕汞管–冷原子荧光光谱法（CVAFS）测定大气中TGM的方法、微型捕集管–CVAFS测定大气中TPM的方法、镀KCl直形扩散管–金捕汞管串联采集RGM与GEM的方法。每种形态汞的测量技术水平都在pg•m-3量级。并在国内首次实现了对城市大气中GEM、RGM、TPM的同步测量。 2.2005 ~ 2006年间贵阳市中心城区大气中GEM、RGM、TPM的平均浓度分别是9.11 ng•m-3、132.4 pg•m-3、1.02 ng•m-3，均为对照点的1.5倍，都显著高于全球背景参考值1.5 ~ 2.0 ng·m-3、< 10 pg•m-3、1 ~ 86 pg•m-3。3种形态汞的季节、昼夜与空间分布特征如下：⑴GEM：①季节平均浓度表现为冬季＞夏季＞春季，居民采暖燃煤释放是造成冬季GEM浓度高的主要原因。②春、夏非采暖季受释放源及其排放方式、自身物理化学性质与气候条件等因素的影响一般是夜间高于白天；冬季则受居民白天采暖燃煤影响主要表现为白天高于夜间。③年平均浓度，工业区＞居民区＞商业区＞游览区＞对照点。⑵RGM：①季节平均浓度表现为春季＞夏季＞冬季，气候条件对RGM的影响较大。②受白天释放源、自身物理化学性质、大气氧化强度与气候条件等因素的影响，春、夏、冬3季一般都为白天高于夜间。③年平均浓度，商业区＞工业区、居民区＞游览区、对照点。⑶TPM：①季节平均浓度表现为冬季＞夏季＞春季，居民采暖燃煤释放是造成冬季TPM浓度高的主要原因。②受释放源及其排放方式、自身物理化学性质与气候条件等因素的影响，春、夏、冬3季一般都为夜间高于白天。③年平均浓度，工业区＞居民区＞商业区＞对照点＞游览区。④TPM受局地释放源的影响显著，而燃煤释放是其冬季的普遍来源。 3.2005 ~ 2006年间不同形态汞在贵阳市中心城区大气中的含量分布为GEM（89.8 %）> TPM（8.8 %）> RGM（1.5 %），其中（RGM + TPM）占大气总汞（TAM）的比例略高于对照点的10.0 %，但显著高于全球背景参考值1 ~ 5 %，说明贵阳市中心城区大气汞向地表生态系统的沉降通量相对背景区较大。因为尽管RGM、TPM在大气中的含量很低，但正是它们控制了大气汞向地表生态系统的沉降速率。 4.2005 ~ 2006年间贵阳市中心城区各功能区及对照点大气中不同形态汞日均浓度的相关关系大多数都表现为不显著，表明在贵阳市中心城区及对照点大气中不同形态汞的来源可能是多元化的。 5.2005 ~ 2006年间贵阳市中心城区大气中GEM、RGM、TPM的干沉降通量平均值分别为28.7 μg•m-2•yr-1、10.4 μg•m-2•yr-1、160.9 μg•m-2•yr-1，均为对照点的1.5倍，其中TPM控制了大气汞向地表生态系统的干沉降通量；TAM干沉降通量平均值为200.1 μg•m-2•yr-1，其时空差异表现为冬季＞春季＞夏季和工业区＞居民区＞商业区＞对照点＞游览区。 6.经估算，2005 ~ 2006年间在贵阳市中心城区面积范围内大气汞干、湿沉降总量为54.7 kg•yr-1，它仅占燃煤向大气排汞量（以2003年为例，贵阳市中心城区燃煤向大气排汞量为334 kg•yr-1）的16.4 %，说明贵阳市中心城区的大部分大气汞仍然停留在大气中，最终将经由大气进行长距离迁移，散布到更广的区域。 7.在中国科学院地球化学研究所，2000 ~ 2006年间的大气TGM污染程度呈逐年递增趋势；2004年大气汞的干沉降通量为16.5 ng•m-2•h-1，高于湿沉降通量12.2 ng•m-2•h-1。 8.贵阳市中心城区及对照点不同类型土壤THg含量的几何平均值分别是0.370和0.276 mg•kg -1，都高于贵阳市土壤汞背景值0.201 mg•kg -1。土壤释汞是贵阳市大气气态总汞的一个重要自然源，而土壤THg含量是土壤释汞的最主要影响因子。因此，为了提高城乡居民的生活环境质量，更为了保护城乡居民的健康，非常有必要采取防治措施来降低贵阳市中心城区及对照点的土壤汞污染。 9.贵阳市中心城区苔藓THg平均含量为0.258 mg•kg -1，为对照点的1.5倍；中心城区某些常见的木本植物叶片THg含量范围是 0.068 ~ 0.181 mg•kg -1，木本植物叶片吸收大气汞的能力表现为落叶植物＞常绿植物。苔藓、梧桐叶片中的THg含量与其生长时期的大气汞浓度密切相关，能够指示区域大气汞的污染现状与空间分布规律。

中国炼锌向大气排汞及其环境影响的初步研究

汞是一种毒性极强的环境污染物。由于汞能在大气中存在并能长距离迁移，因此汞已经被定义为全球性污染物。研究表明有色金属锌的冶炼是大气汞的一个重要的人为汞污染源。西方发达国家在炼锌过程中由于有严格的污染物控制措施，使得这个问题得到有效的控制。由于经济和技术的原因我国大多数锌冶炼企业在冶炼过程中没有进行烟气汞的回收，从而使得我们不能借鉴国外的相关研究成果。我国2005年精锌总产量占到了世界的1/4，是全世界最大的锌锭生产国家，但相关的研究却非常滞后。近年来我国锌冶炼向大气排汞的问题已经引起了国际争议，而且冶炼过程中排放的汞对局部生态系统会产生重要影响，因此锌冶炼过程中释放汞所造成的环境问题已经越来越受到人们的关注和重视。 本研究的目的是通过对不同锌矿山的锌矿石和浮选锌精矿以及冶炼厂不同源锌精矿的研究从而了解我国的矿石汞含量，及矿石浮选过程中汞的分配；通过对冶炼过程向大气排汞的研究，认识锌精矿中汞在锌冶炼过程中的分配，估算不同冶炼方式汞的释放因子。如A、B和C冶炼厂是用不同的工艺来炼锌的，其汞的释放因子也不同。通过对土法炼锌区和工业炼锌区水体、土壤、大气和植物中汞的分布、迁移转化规律的研究，认识锌冶炼对局部生态系统产生的影响。 1.矿石和锌精矿中汞的研究 成因和分类不同的铅锌矿床锌矿石和浮选锌精矿中汞的测定结果表明：凡口矿的矿石和浮选的锌精矿中汞含量比兰坪矿矿石和浮选锌精矿高了2个数量级。凡口矿锌矿石和锌精矿中汞的含量分别是64.5-107 mg∙kg-1，588-602 mg∙kg-1；对应兰坪矿锌矿石和锌精矿中汞的含量分别是0.23~0.40 mg∙kg-1，1.91-3.33 mg∙kg-1。不同冶炼厂不同矿源的锌精矿中汞含量测定结果表明：不同源锌精矿中汞含量在0.10-1100 mg∙kg-1之间，变动范围非常大。而冶炼厂冶炼所用的混合锌精矿中汞含量差别不大，冶炼所用的混和锌精矿汞含量在37-105 mg∙kg-1之间变动。 2.锌精矿中汞在冶炼过程中的分配和汞释放因子的研究 对采用不同炼锌工艺的冶炼厂和有除汞工艺的A、B冶炼厂所用的锌精矿中的汞在冶炼过程分配的质量平衡对比表明，A冶炼厂和B冶炼厂锌精矿中的汞在冶炼过程中的分配显著不同，主要制约因素是是否对烟气中汞进行回收。在烟气到达除汞设备前，A和B冶炼厂在焙砂和尘、酸洗、电除雾等流程对烟气中汞的去除效果相近。不同的是，A厂要进行烟气汞回收，烟气经过汞回收后，50%以上烟气中的汞在这一流程被去除。这使得A、B冶炼厂后续的流程制酸吸收汞和排向大气汞所占的比例有较大的差异。 不同冶炼方式的汞释放因子表明，无任何环保措施的土法炼锌活动的释汞因子为113 g·t-1，不对烟气汞进行回收的B厂和C冶炼厂汞的释放因子分别为49 g·t-1和243 g·t-1，对烟气汞回收的A冶炼厂汞的释放因子为5.7 g·t-1。综合各种不同炼锌方式的汞释放因子及其精锌产量，得出了锌冶炼过程中汞的综合释放因子，从而估算出我国锌冶炼向大气排汞量约61.3-178 t·y-1。 3.锌冶炼对局部生态系统的影响 炼锌区的冶炼废渣是冶炼过程中的主要废弃物，随意堆放的废渣是当地农田土壤的重要汞污染源，大气汞中活性汞和颗粒态汞的沉降也是当地农田土壤另一个汞污染源。土法炼锌区和工业炼锌区土壤分析结果表明，工业炼锌对局部环境的影响更为严重。土壤汞含量对比如下：A冶炼厂周边环境污染土壤汞含量259-2990 μg·kg-1，远高于威宁土法炼锌点污染土壤汞含量72-355 μg·kg-1。威宁土法炼锌点土壤中甲基汞含量的分析表明，在冶炼点附近的土壤中甲基汞绝对含量和甲基汞/总汞的比例都高于其它样点，说明冶炼点附近土壤中汞的甲基化水平提高。A冶炼厂污水处理渣亦没有得到妥善的处理，成为当地潜在的汞污染源。 土法炼锌区水体汞的含量明显受到冶炼渣的影响。工业炼锌过程产生的废水经处理后的水汞含量100%超过国家工业废水排放标准，这些处理后的水的排放是当地重要的汞污染源。A冶炼厂周边稻田水分析表明，溶解态甲基汞占溶解态总汞的的平均比率（5%）远高于一般自然水体（<1%），可能与稻田特殊环境有关。 土法炼锌区大气汞含量测定表明，冶炼点附近大气汞浓度剧增，高达5220 ng·m-3，锌冶炼是当地主要的大气汞污染源。大气汞浓度的提升，是导致农作物玉米叶部位汞含量增高的原因。植物体的地上绿色部分通过叶片吸收大气汞是植物体内汞富集的重要途径之一。 土法炼锌区和工业炼锌区农作物果实中汞含量的测定结果对比如下：A冶炼厂附近稻田产出的部分大米样品中总汞含量已经超过了国家食品限量卫生标准（20 µg·kg-1），所有辣椒中总汞含量全部超出了国家蔬菜卫生限量标准（10 µg·kg-1）。土法炼锌区所取农作物样品未出现果实汞含量超标现象。食用这些汞含量超标的食物将对当地居民带来潜在的危害。

天然溶解有机质和环境污染物的相互作用--以铜、汞离子和卡马西平为例

天然溶解有机质（natural dissolved organic matter，DOM）是由动植物残体经过复杂的物理、化学和生物过程形成的高分子有机混合物，它广泛分布于水体、土壤和沉积物中。DOM的结构十分复杂，分子量从几百到几十万不等，元素组成和化学结构随时空和来源不同而变化。腐殖物质是DOM的主要组成部分，以溶解有机碳计约占DOM总量的50%~80%。腐殖物质可以分为：富里酸（fulvic acid， FA任何pH值条件下都溶于水），腐殖酸（humic acid，HA在pH 1时不溶于水）和胡敏素（humin，任何pH条件下都不溶于水）。 DOM能影响许多生物地球化学过程。例如DOM是一个重要的碳汇，它能影响微生物的食物链和全球碳循环；DOM和营养元素含量、食物链结构等一起决定水生生态系统的属性和发展动态；它还能吸收自然光，从而影响紫外线在水中的穿透能力和浮游植物的光合作用；DOM含有多种弱酸和弱碱官能团，是天然水体pH的调节剂和控制因素；DOM和痕量金属离子或有机污染物发生作用，从而影响它们的形态、毒性、迁移转化和生物有效性；在饮用水消毒过程中，DOM能生成致癌物三卤甲烷和其它消毒副产物。 天然水体中的痕量金属离子（如Cu2+和Hg2+）主要以DOM络合态存在。在海水中DOM控制铜的主要存在形态；在淡水中 90%以上的铜离子与DOM发生配位。通过配位作用DOM能抑制浮游生物对Hg的吸收，增加鱼类对Hg的蓄积。目前，人们对金属离子在环境中的迁移转化机理的理解还不够深入，尤其是对有机质参与下的有毒重金属循环还缺乏必要地认识。条件稳定常数是描述重金属离子与DOM配位能力的基本参数。前人运用多种手段对DOM与金属离子的结合能力进行了研究，主要包括：离子选择性电极法、溶出伏安法、超滤及荧光淬灭滴定法等。紫外吸收滴定法可用于研究单一有机化合物和金属离子的相互作用，在这一领域的应用尚未报道。本文首次将紫外吸收滴定法应用于测定DOM与Cu2+和Hg2+的条件稳定常数。实验表明紫外吸收滴定法迅速、简便、可望成为研究DOM和痕量金属离子相互作用的有力工具。 药品和个人护理品（pharmaceuticals and personal care products，PPCPs）在环境中普遍存在。有证据表明，环境中的有些PPCPs能对生物体产生影响，如改变生物体的性别比例，影响植物生长，动物幼虫的孵化，甚至具有明显的致畸效应。卡马西平（Carbamazepine，CBZ）是一种常用的抗癫痫、止痛药物和抗抑郁药。毒理学实验表明，环境中的CBZ能严重影响鱼、蚌等水生生物的免疫和循环系统。CBZ使用量大，在环境中含量高，在地下水渗透过程和常规污水处理中保持稳定，因此CBZ成为衡量人类活动和污水处理工艺效率的标志物。但是目前人们对CBZ的环境地球化学循环知之甚少。DOM能与许多有机污染物发生相互作用，从而影响它们的生物环境地球化学行为，但DOM对CBZ的影响尚未见报道。本论文利用三维荧光光谱技术和同步荧光光谱技术，研究了DOM与CBZ的结合强度、结合类型、影响因素，并且初步总结了DOM对CBZ环境地球化学循环的影响。为理解其它PPCPs的生物地球化学循环，预测它们的迁移转化、归宿和环境毒性提供参考。 本文运用紫外吸收滴定法和荧光淬灭滴定法研究了不同来源的DOM和金属离子（Cu2+和Hg2+）的相互作用，运用三维荧光光谱法和同步扫描荧光光谱法研究了DOM和卡马西平的相互作用。主要成果简述如下： 1、本文首次将紫外吸收滴定法应用于测定金属离子和DOM的条件稳定常数，结果表明紫外吸收滴定法操作更简便、测定迅速、仪器普及率高，可在DOM含量很低（约10-5 ~ 10-7 mol/L）的情况下也可以直接进行测定，不必进行复杂的预富集。可望成为DOM和痕量有毒重金属离子相互作用的有力工具。 2、重金属离子（Hg2+和Cu2+）与DOM的羧基和酚羟基等基团配位。配位后电子的离域性增加，导致紫外吸收增加。与此同时配位后分子极性的改变和铜离子顺磁性作用，引起DOM荧光淬灭。在Cu2+和Hg2+的滴定过程中，紫外吸光度和荧光强度之间呈极显著线性负相关关系（R2=0.99，P<0.001）。这说明荧光和紫外从不同侧面揭示了DOM和金属离子的配位作用。 3、紫外吸收滴定法和荧光淬灭滴定法测定其条件稳定常数（log K）一致，介于3.5 ~ 5.5之间。强配位作用是DOM影响有毒重金属离子环境地球化学行为的根源。研究还表明配位作用的强弱受DOM来源和体系pH的影响。 4、 CBZ和DOM能发生强烈的相互作用，结合常数（log K）介于3.41 ~ 5.04之间。DOM能明显减少游离态CBZ的浓度，提高CBZ溶解度和迁移转化能力。这对认识CBZ和其它PPCPs的环境地球化学循环及其影响因素具有指导意义。 5、荧光光谱研究表明CBZ对DOM发射的荧光具有明显的猝灭作用，其猝灭机理为静态猝灭。疏水作用是CBZ和DOM之间的主要作用力。DOM-CBZ受pH值的影响不大， Cu2+对CBZ和DOM的结合有一定的影响。