基于模糊四元联系数的防洪工程体系安全综合评价模型

防洪工程体系是由随机、模糊、未确知等众多不确定性因子组成的复杂系统,它至今仍是洪水灾害管理的主体,对该体系综合安全进行定量评价可为洪水灾害管理提供重要依据.模糊四元联系数是集对分析中同异反联系数的推广,它可更深入地分析系统中的各种不确定性.利用模糊四元联系数建立了防洪工程体系安全综合评价模型,用联系度可描述评价对象与评价标准之间的关系,其结果简便直观,能清晰地反应评价对象和评价标准间的动态联系.用该模型综合评价了实际防洪工程体系的安全程度,其结果与物元分析等方法所得结果一致.     

西安城市暴雨内涝灾害气象预警系统研究

介绍了西安城市暴雨内涝灾害气象预警系统的技术路线及原理.该系统包含本地化的城市暴雨内涝仿真模型,并以城区加密气象自动站资料、多普勒雷达降水估算产品、数值预报产品、主观预报等作为实况和模拟用的降雨边界条件,结合西安市区地理地貌特征、城市规划、排水系统特征、排水规则、防洪工程等多方面的非气象资料建立而成,具备一定的内涝动态监测预报能力.对2006年6月3日内涝过程进行了模拟,效果较好,能够满足预警需求.     

基于TM与MODIS遥感数据的农业旱情监测——以河北省为例

以河北省冬小麦种植区域为研究区,基于TM和MOD IS遥感数据,利用植被供水指数法确定了研究区旱情等级。首先,将其与遥感解译获得的冬小麦空间分布图叠加得到受灾冬小麦空间分布图;然后以1 km的距离在受灾冬小麦周围做缓冲区,并与通过人口密度模型获得的人口密度空间分布图叠加,得出受灾人口空间分布;最后基于光能利用率改进模型构建粮食产量回归统计模型,得到粮食产量。目的是从粮食产量和作物受灾影响人口两个方面对农业受干旱影响情况进行遥感监测和定量评价,以期为相关部门制定防灾、抗灾措施提供科学依据。结果表明,2004年研究区:(1)春季受灾面积小,仅占16.4%;(2)旱情较轻,以轻旱为主,占受灾面积的89%;(3)冬小麦种植面积约为23 965.0 km2,受灾面积约606.3 km2,主要位于唐山市和保定市;(4)粮食产量回归统计模型精度达到了87%,冬小麦产量约为11939247 t,单产约为498.8 t/km2。     

阵性泥石流运动与堆积的欧拉─拉格朗日模型──Ⅰ.理论

自然界中的泥石流具有突发性和非恒定性的特点。为了模拟典型泥石流现象,在流团模型的 基础上,进一步完善了基于欧拉─拉格朗日（Ｅ—Ｌ）观点的ＰＩＣ（Ｐａｒｃｅｌ　Ｉｎ　Ｃｅｌｌ）算法,细化了流元结 构,建立了能够模拟典型阵性泥石流发生、运动和堆积的准结构两相流模型。求解该模型不仅可以 模拟泥石流运动过程,而且可以对泥石流的堆积过程、停积形态、冲刷特征及泥石流中多组分颗粒 的分选特征进行定量描述。     

A fluorescence-based bioassay for aquatic macrophytes and its suitability for effect analysis of non-photosystem II inhibitors

Background, Goals and Scope During the last years the miniaturization of toxicity test systems for rapid and parallel measurements of large quantities of samples has often been discussed. For unicellular algae as well as for aquatic macrophytes, fluorescence-based miniaturized test systems have been introduced to analyze photosystem II (PSII) inhibitors. Nevertheless, high-throughput screening should also guarantee the effect detection of a broad range of toxicants in order to ensure routinely applicable, high-throughput measuring device experiments which can cover a broad range of toxicants and modes of action others than PSII inhibition. Thus, the aim of this study was to establish a fast and reproducible measuring system for non-PSII inhibitors for aquatic macrophyte species to overcome major limitations for use. Methods A newly developed imaging pulse-amplitude-modulated chlorophyll fluorometer (I-PAM) was applied as an effect detector in short-term bioassays with the aquatic macrophyte species Lemna minor. This multiwell-plate based measuring device enabled the incubation and measurement of up to 24 samples in parallel. The chemicals paraquat-dichloride, alizarine and triclosan were chosen as representatives for the toxicant groups of non-PSII herbicides, polycyclic aromatic hydrocarbons (PAHs) and pharmaceuticals and personal care products (PPCPs), which are often detected in the aquatic environment. The I-PAM was used (i) to establish and validate the sensitivity of the test system to the three non-PSII inhibitors, (ii) to compare the test systems with standardized and established biotests for aquatic macrophytes, and (iii) to define necessary time scales in aquatic macrophyte testing. For validation of the fluorescence-based assay, the standard growth test with L. minor (ISO/DIS 20079) was performed in parallel for each chemical. Results The results revealed that fluorescence-based measurements with the I-PAM allow rapid and parallel analysis of large amounts of aquatic macrophyte samples. The I-PAM enabled the recording of concentration-effect-curves with L. minor samples on a 24-well plate with single measurements. Fluorescence-based concentration-effect-curves could be detected for all three chemicals after only 1 h of incubation. After 4–5 h incubation time, the maximum inhibition of fluorescence showed an 80–100% effect for the chemicals tested. The EC50 after 24 h incubation were estimated to be 0.06 mg/L, 0.84 mg/L and 1.69 mg/L for paraquatdichloride, alizarine and triclosan, respectively. Discussion The results obtained with the I-PAM after 24 h for the herbicide paraquat-dichloride and the polycyclic aromatic hydrocarbon alizarine were in good accordance with median effective concentrations (EC50s) obtained by the standardized growth test for L. minor after 7 d incubation (0.09 mg/L and 0.79 mg/L for paraquat-dichloride and alizarine, respectively). Those results were in accordance with literature findings for the two chemicals. In contrast, fluorescence-based EC50 of the antimicrobial agent triclosan proved to be two orders of magnitude greater when compared to the standard growth test with 7 d incubation time (0.026 mg/L) as well as with literature findings. Conclusion Typically, aquatic macrophyte testing is very time consuming and relies on laborious experimental set-ups. The I-PAM measuring device enabled fast effect screening for the three chemicals tested. While established test systems for aquatic macrophytes need incubation times of ≥ 7 d, the I-PAM can detect inhibitory effects much earlier (24 h), even if inhibition of chemicals is not specifically associated with PSII. Thus, the fluorescence-based bioassay with the I-PAM offers a promising approach for the miniaturization and high-throughput testing of chemicals with aquatic macrophytes. For the chemical triclosan, however, the short-term effect prediction with the I-PAM has been shown to be less sensitive than with long-term bioassays, which might be due to physicochemical substance properties such as lipophilicity. Recommendations and Perspectives The results of this study show that the I-PAM represents a promising tool for decreasing the incubation times of aquatic macrophyte toxicity testing to about 24 h as a supplement to existing test batteries. The applicability of this I-PAM bioassay on emergent and submerged aquatic macrophyte species should be investigated in further studies. Regarding considerations that physicochemical properties of the tested substances might play an important role in microplate bioassays, the I-PAM bioassay should either be accompanied by evaluating physicochemical properties modeled from structural information prior to an experimental investigation, or by intensified chemical analyses to identify and determine nominal concentrations of the toxicants tested. The chemicals paraquat-dichloride, alizarine and triclosan were chosen as representatives for the toxicant groups of non-PSII herbicides, PAHs and PPCPs which are often detected in the aquatic environment. Nevertheless, in order to ensure a routinely applicable measuring device, experiments with a broader range of toxicants and samples of surface and/or waste waters are necessary. ESS-Submission Editor: Dr. Markus Hecker (MHecker@Entrix.com)     

Co-treatment of hydrogen sulfide and methanol in a single-stage biotrickling filter under acidic conditions

Biofiltration of waste gases is cost-effective and environment-friendly compared to the conventional techniques for treating large flow rates of gas streams with low concentrations of pollutants. Pulp and paper industry off-gases usually contain reduced sulfur compounds, such as hydrogen sulfide and a wide range of volatile organic compounds (VOCs), e.g., methanol. It is desirable to eliminate both of these groups of compounds. Since the co-treatment of inorganic sulfur compounds and VOCs in biotrickling filters is a relatively unexplored area, the simultaneous biotreatment of H2S and methanol as the model VOC was investigated. The results showed that, after adaptation, the elimination capacity of methanol could reach around 236 g m(-3) h(-1) with the simultaneous complete removal (100%) of 12 ppm H2S when the empty bed residence time is 24 s. The pH of the system was around 2. Methanol removal was hardly affected by the presence of hydrogen sulfide, despite the low pH. Conversely, the presence of the VOC in the waste gas reduced the efficiency of H2S biodegradation. The maximal methanol removal decreased somewhat when increasing the gas flow rate. This is the first report on the degradation of methanol at such low pH in a biotrickling filter and on the co-treatment of H2S and VOCs under such conditions.     

Bibliography of Environmental Studies in Natural Characteristics and Anthropogenic Influences on the Ganga River

During the second half of the 20th century, the Ganga River ecosystem has been continuously altered by several ongoing anthropogenic processes, accommodating multi-dimensional pressure due to increase of nearly four-fold human population. For solution of any environmental issues of the river, the Earth System Science approach is required to have maximum socio-economic benefits to millions of people living in Indian and Bangladesh. A bibliography containing more than 250 references on environmental studies of the Ganga River was prepared to preserve its ecosystem by providing the baseline support in this regard.     

Evaluation of marine outfall with three-dimensional hydrodynamic and water quality modeling

Numerical models are often used to evaluate the potential impact of human alternation of natural water bodies and to help the design of the alternation to mitigate its impacts. In the past decade, three-dimensional hydrodynamic and reactive transport modeling has matured from a research subject to a practical analysis technology. This paper presents a practical study in which a three-dimensional hydrodynamic and water quality model [hydrodynamic eutrophication model (HEM-3D)] was applied to determine the optimal location for treated wastewater discharged from marine outfall system in the Keelung harbor and the adjacent coastal sea. First, model validation was conducted with respect to surface elevation, current, and water quality variables measured in the Keelung harbor station and its coastal sea. The overall performance of the model was in qualitative agreement with the available field data. The model was then used to evaluate several scenarios of the locations from marine outfall system. Based on model simulation results, a location at the northeast of Ho-Ping Island was recommended for adoption because the environmental impact is smaller than any other alternative.

How Plants Cope with Foreign Compounds. Translocation of xenobiotic glutathione conjugates in roots of barley (Hordeum vulgare) (9 pp)

Background, Aim and Scope Numerous herbicides and xenobiotic organic pollutants are detoxified in plants to glutathione conjugates. Following this enzyme catalyzed reaction, xenobiotic GS-conjugates are thought to be compartmentalized in the vacuole of plant cells. In the present study, evidence is presented for long range transport of these conjugates in plants, rather than storage in the vacuole. To our knowledge this is the first report about the unidirectional long range transport of xenobiotic conjugates in plants and the exudation of a glutathione conjugate from the root tips. This could mean that plants possess an excretion system for unwanted compounds which give them similar advantages as animals. Materials and Methods: Barley plants (Hordeum vulgare L. cv. Cherie) were grown in Petri dishes soaked with tap water in the greenhouse. - Fluorescence Microscopy. Monobromo- and Monochlorobimane, two model xenobiotics that are conjugated rapidly in plant cells with glutathione, hereby forming fluorescent metabolites, were used as markers for our experiments. Their transport in the root could be followed sensitively with very good temporal and spatial resolution. Roots of barley seedlings were cut under water and the end at which xenobiotics were applied was fixed in an aperture with a thin latex foil and transferred into a drop of water on a cover slide. The cover slide was fixed in a measuring chamber on the stage of an inverse fluorescence microscope (Zeiss Axiovert 100). - Spectrometric enzyme assay. Glutathione S-transferase (GST) activity was determined in the protein extracts following established methods. Aliquots of the enzyme extract were incubated with 1-chloro-2,4-dinitrobenzene (CDNB), or monochlorobimane. Controls lacking enzyme or GSH were measured. - Pitman chamber experiments. Ten days old barley plants or detached roots were inserted into special incubation chambers, either complete with tips or decapitated, as well as 10 days old barley plants without root tips. Compartment A was filled with a transport medium and GSH conjugate or L-cysteine conjugate. Compartments B and C contained sugar free media. Samples were taken from the root tip containing compartment C and the amount of conjugate transported was determined spectro-photometrically. Results: The transport in roots is unidirectional towards the root tips and leads to exsudation of the conjugates at rates between 20 and 200 nmol min-1. The microscopic studies have been complemented by transport studies in small root chambers and spectroscopic quantification of dinitrobenzene-conjugates. The latter experiments confirm the microscopic studies. Furthermore it was shown that glutathione conjugates are transported at higher rates than cysteine conjugates, despite of their higher molecular weights. This observation points to the existence of glutathione specific carriers and a specific role of glutathione in the root. Discussion: It can be assumed that long distance transport of glutathione conjugates within the plant proceeds like GSH or amino acid transport in both, phloem and xylem. The high velocity of this translocation of the GS-X is indicative of an active transport. For free glutathione, a rapid transport-system is essential because an accumulation of GSH in the root tip inhibits further uptake of sulfur. Taking into account that all described MRP transporters and also the GSH plasmalemma ATPases have side activities for glutathione derivatives and conjugates, co-transport of these xenobiotic metabolites seems credible. - On the other hand, when GS-B was applied to the root tips from the outside, no significant uptake was observed. Thus it can be concluded that only those conjugates can be transported in the xylem which are formed inside the root apex. Having left the root once, there seems to be no return into the root vessels, probably because of a lack of inward directed transporters. Conclusions: Plants seem to possess the capability to store glutathione conjugates in the vacuole, but under certain conditions, these metabolites might also undergo long range transport, predominantly into the plant root. The transport seems dependent on specific carriers and is unidirectional, this means that xenobiotic conjugates from the rhizosphere are not taken up again. The exudation of xenobiotic metabolites offers an opportunity to avoid the accumulation of such compounds in the plant. Recommendations and Perspectives: The role of glutathione and glutathione related metabolites in the rhizosphere has not been studied in any detail, and only scattered data are available on interactions between the plant root and rhizosphere bacteria that encounter such conjugates. The final fate of these compounds in the root zone has also not been addressed so far. It will be interesting to study effects of the exuded metabolites on the biology of rhizosphere bacteria and fungi.     

Endpoint ‘floating leaves’ of <Emphasis Type="Italic">Potamogeton natans</Emphasis>: A new method to evaluate the development of macrophytes in pond mesocosms

Goal, Scope and Background One of the advantages of long-term mesocosm experiments as compared to short-term standard toxicity tests in the laboratory is the potential for detecting secondary effects due to the interaction of species and recovery with biomass of macrophytes being an important endpoint. However, generating biomass data by harvesting is often laborious, time-consuming, costly and restricted to the end of the experiment. Moreover, valuable information may get lost, in particular in single application studies, since maximal primary effects and secondary effects or recovery occur per se at different times. Potamogeton natans was used as an example in order to test whether number and area of floating leaves can be reliably measured and be used as intermediate and final endpoints in mesocosm effect studies. Methods Digital photos, which were taken of the water surface in the course of an indoor pond mesocosm study on herbicide effects, were subjected to image analysis. The results were compared to wet weight and ash-free dry weight of Potamogeton at the end of the herbicide study. Results and Discussion Both number and area of floating leaves indicated the same herbicide effects as wet weight and ash-free dry weight of Potamogeton. Error introduced by the different work steps is small and can be further minimised by a number of method improvements. Recommendations and Perspectives In indoor mesocosm studies, errors due to the perspective adjustment may be circumvented by taking the photos perpendicular to the water surface. Correction for lens aberration, identical light conditions and the use of fluorescence images are considered promising. Field applications are proposed.