甲基叔丁基醚（MTBE）在不同粘性土壤中的吸附特性

土壤对有机物的吸附是污染土壤及地下水原位修复技术中的重要参数.通过静态间歇吸附实验研究了甲基叔丁基醚(MTBE)在不同粘性土壤中的吸附特性.结果表明,MTBE在粘性土壤中的吸附行为均可用线性方程很好描述,粘粒是土壤对MTBE吸附的主要影响因素,吸附常数与土壤粘粒含量呈y=4.382×10-3x-0.817 ×10-3直线关系.对不同温度下的吸附数据分析发现,粘性土壤对MTBE的平衡吸附量随温度的升高而降低,由吸附热力学推导可得等量吸附焓变△H与平衡吸附量无关,且△H＜0,表明该吸附为故热过程.     

不同粒径土壤对氯丹的吸附性能及其急性毒性

以典型有机氯农药氯丹为研究对象,重点研究了不同粒径土壤颗粒对氯丹的吸附特性及其对发光菌急性毒性的影响。研究结果表明,不同粒径的土壤颗粒对氯丹的吸附性能依次为:粘粒(2μm)≈粉粒(2~20μm)粗砂(200~2 000μm)细砂(20~200μm)。Freundlich等温吸附模型的线性相关系数最小为0.84,对不同粒径土壤吸附数据的拟合均优于Langmuir等温吸附模型。对吸附氯丹的吸附数据更符合准一级吸附动力学,其线性相关系数最高达到0.999。四种土壤颗粒浸出液对发光菌毒性的发光抑制率依次为细砂(-21%)≈粗砂(-21%)粘粒(-13%)粉粒(-9%),即发光菌的急性毒性与土壤颗粒的吸附性能负相关。     

滇池流域不同土壤类型和土地利用方式的土壤中溶解性有机碳的流失特性研究

采集滇池流域不同土壤类型、不同土地利用方式下的土壤样品,进行土壤中溶解性有机碳(DOC)的静态解吸实验,通过测定不同时间下溶入水相的COD量,探究不同土壤类型及土地利用方式下DOC的流失特性,从而揭示不同土地利用方式对滇池流域面源污染的影响.结果表明,同一土地利用方式的不同类型土壤中DOC的溶出平衡时间为壤土＞粘土＞粘壤土,其中退耕区(粘壤土＞粘土＞壤土)、大棚(粘土＞粘壤土=壤土)土壤不符合该规律,溶出平衡时间基本为1.5～2.5h；不同的土壤类型和土地利用方式下,DOC的溶出率为1.00％～2.75％,同一土地利用方式的不同类型土壤中DOC的溶出率存在一定差别,这是由于不同类型的土壤中砂粒、粉粒、粘粒的含量有所差异.     

磺胺间甲氧嘧啶在土壤中的吸附/解吸特性研究

通过吸附/解吸动力学、吸附/解吸热力学试验研究了磺胺间甲氧嘧啶(SMM)在河南土壤上的吸附/解吸行为,并分析了影响SMM吸附/解吸的因素。结果表明,SMM在土壤中的吸附系数为18.9mL/g,土壤有机碳吸附系数为466.2mL/g,SMM在土壤中具有一定的移动性,对地下水和地表水存在一定的污染风险;描述SMM吸附过程的最优动力学方程为一级反应动力学方程,土壤对SMM的吸附近似于一级反应,且SMM在土壤中的吸附以物理吸附为主;用Freundlich方程来描述SMM在土壤的等温吸附行为最适宜,且SMM在土壤中的吸附经验常数的倒数均小于1,属于L-型吸附等温线。     

不同利用方式土壤中磷的吸附与解吸特性

研究不同利用方式土壤对磷的吸附解吸特性及其影响因素。采用室内恒温培养法研究了湖南典型土壤(红壤、潮土和紫色土)的不同利用方式(旱地、水田)土壤对P的吸附和解吸过程。土壤对磷的吸附解吸过程是分阶段进行的,用Langmuir方程拟合程度比Freundlich方程高,相关系数均在0.90(P<0.05)以上;从最大吸附量(Qm)、吸附反应常数(K)和最大缓冲容量(MBC)3项吸附参数综合考虑,旱地对P的吸附无论在强度还是容量方面均大于同母质的水田土壤;解吸率随着吸附量的增加而增大,其大小为旱地<水田。Qm与<0.002 mm粘粒及无定形铁含量呈正相关,相关系数分别为0.95和0.94(P<0.05)。不同利用方式土壤P吸附解吸特性差别较大,针对不同土壤应采取不同的磷素管理措施以实现作物增产和保护环境的双重效益。     

不同复垦年限煤矸山土壤重金属有效态含量及其影响因素分析

研究煤矸山不同年限复垦土壤重金属有效态含量及其影响因素对指导煤矸山植被复垦及复垦地利用具有重要意义。以山西省典型煤矸山复垦3、10、16年灌草地为研究对象,分析了3种复垦土样的理化性质及重金属Cd、Pb、Cu的总量、有效态含量、生物有效性系数。结果表明:(1)3种复垦土样电导率(EC)、有机质和碱解氮含量均随复垦年限的增加而增加,但黏粒和有效磷含量呈下降趋势;(2)总体看来,3种复垦土样Cd、Pb、Cu有效态含量随复垦年限的增加而增加,Cd、Pb生物有效性系数在0~40cm土层、Cu生物有效性系数在20~40cm土层也有此趋势;(3)土壤pH、EC、有机质、黏粒质量分数均不同程度地影响煤矸山复垦土壤Cd、Pb、Cu有效态含量,其中有机质和黏粒含量是关键影响因子。     

不同粒径泥沙理化特性对磷吸附过程的影响

以北京大兴南海子湖表层沉积物为研究对象,测试分析了0.147～0.246 mm(细砂)、0.074～0.147 mm(极细砂)、0.0385～0.0740 mm(粉粒)和<0.0385 mm(粉粒粘粒混合物)4种粒径泥沙对磷的吸附行为,并采用相关分析及逐步回归分析探讨不同粒径沉积物中有机质(OM)、Fe、Al、Ca、Mn和TP含量对磷吸附过程的影响。结果表明,二级动力学方程和Langmuir模型能较好地描述南海子不同粒径泥沙的吸附动力学及等温吸附过程(R2>0.90)。粒径对单位质量泥沙吸附磷量具有明显影响,粉粒粘粒混合物>粉粒>细砂>极细砂。总体上,泥沙有机质(OM)、TP、Fe、Al、Ca和Mn含量随粒径的减小而增大,且粘粒对其影响较大。不同粒径泥沙(OM)、Fe、Al、Ca和Mn含量之间存在极显著正相关关系(P<0.01),且均对单位质量泥沙最大吸附量(Xm)和饱和吸附量(Cse)具有正效应,其中Al含量对该参数的影响更为显著。这说明泥沙对磷的吸附行为可能受到粒径和化学成分的共同影响。     

内蒙古某电厂周围土壤汞分布特征及其影响因素

研究内蒙古草原两燃煤电厂附近土壤中汞含量分布特征及其与土壤性质的关系。结果表明,48.15%的供试土壤汞含量超出当地土壤汞含量背景上限值,且距电厂越近,汞含量越高。距电厂较远、受污染较小地区的土壤汞含量与土壤理化性质密切相关:土壤p H8.0时,汞含量随p H值升高而减少,p H8.0时,趋势相反;土壤有机质与汞含量呈现出正相关性;土壤颗粒越细,对汞的吸附能力越强,汞含量越高,但当颗粒细至粘粒时,随着粘粒含量的增多,汞含量呈现出减少的趋势。     

污染场地不同深度土壤有机-矿质复合体中有机氯农药的分布

采用物理方法将某农药厂土壤分成4种粒径的有机-矿质复合体组分,粘粒、粉粒、细砂和粗砂,研究有机氯农药在土壤不同有机-矿质复合体组分中的分布特征及有机质含量对污染物质赋存分布的影响。结果表明,粉粒组分中污染物质六六六含量较高,粘粒组分中滴滴涕含量较高。粘粒和粉粒组分中污染物质的含量与相应的有机质含量间呈现显著相关关系,而在细砂和粗砂中这种相关性不显著。lgKoc值与污染物质含量的相关性分析结果与有机质的相关性分析结果相似。有机质可能是影响场地土壤有机氯农药分布的重要因素之一。本研究的结果可为污染场地的风险控制和环境修复提供基础依据。     

颗粒物吸附乐果的动力学特征

研究了乐果在颗粒物表面上吸附的动力学特征,观察了颗粒物的性质对吸附行为的影响.结果表明,乐果在3种颗粒物上的吸附过程均符合一级动力学规律,其相关系数在0.986 2～0.990 5,达到极显著水平.颗粒物的性质与吸附量相关分析发现,不同颗粒物对乐果的吸附程度是由颗粒物的有机质、粘粒、阳离子交换容量(CEC)和pH等理化特征综合作用的结果.pH对吸附行为影响的实验结果指出,随着体系的pH逐渐增大,颗粒物对乐果的吸附能力增强.     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

扬中生态环境建设的思考与实践

结合扬中生态环境的基本情况和存在的不足，进行了具体分析，对扬中未来生态建设的发展方向提出了建议及实施措施。     

实验室质量管理体系内部审核的实施

在实施ISO／IEC17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核实施阶段的关键环节，提出召开首次会议、收集审核证据、确定审核发现和召开末次会议的技术方法，对提高内部审核的质量和有效性、获得可靠的审核结论具有重要意义。     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

Comparison of methods for evaluation of activity of photocatalytic films

Objective

This work aims to investigate the correlation between the photocatalytic activity determined by methylene blue bleaching (DIN 52980), stearic acid degradation, and degradation of acetone in gas phase.

Method

The photocatalytic TiO₂ coatings included in this investigation ranged from thin commercially available coatings (Activ^TM and BioClean^TM) and ready to use suspensions (Nano-X PK1245) to lab-produced PVD and sol?Cgel coatings. XRD analysis of the photocatalytic coatings showed that all the coatings consisted of nanocrystalline anatase, although the thickness and porosity varied considerably.

Results

The study showed that the reproducibility of the activity measurements was good. However, more importantly, the investigation showed that there is a good correlation between the activities determined by the different methods even though the characteristics of the photocatalytic coatings and the organic probe molecules varied considerably.

Conclusion

The overall findings of this work suggest that there is a good correlation between the investigated methods. These results are promising for the future work concerning standardization of methods for determination of the activity of photocatalytic films.     

Impact of overexploitation of shellfish: northeastern coast of India

India has a very extensive coastline of about 7515 km, rich in diverse living resources. These resources continue to deteriorate with rampant harvesting or are altered for other uses such as aquaculture and fisheries. The present paper deals with degrading coastal habitats in northeastern India, and projects the intensity of the stress arising from the collection of tiger prawn seeds (Penaeus monodon) for aquacultural farms and molluskan shells for poultry feed and edible lime. Indiscriminate exploitation of these resources leads to a heavy reduction of the species concerned and other associated marine communities. The magnitude of such destruction has been quantified. The impacts of biodiversity loss and their after-effects on the ecobalance of this coastal system have become a matter of great concern to ecologists to maintain security and sustainability. The authors propose a public awareness program on themes relating to the importance of biodiversity for human livelihoods.