Visualisation of the complexity of EUSES

The interdependencies of parameters applied in the models of EUSES are visualised in a directed connectivity graph. The parameters (inputs, defaults, state variables, outputs) are represented by boxes (nodes) and their relations by lines (edges). The visualisation, on the one hand, clarifies the complexity of the models in EUSES and, on the other hand, creates an overview and transparency. The parameters’ relations to each other can be recognised faster, and the models can be better understood. The complexity was quantified by the number (variety), kind (substance parameter, physico-chemical parameter, concentration, other parameters), and depth (dimension) of the parameter and the number of relations (connectivity). The variety of EUSES (without the modelsSimple Treat andSimple Box whose interior structure is not documented and without the effect and risk characterisation) amounts to 466, the connectivity to 961, and the maximal dimension is 21.     

混凝试验搅拌器的研制

影响混凝效果的因素众多,混凝沉淀烧杯试验是进行水的混合、絮凝、沉淀工艺研究、设计和生产指导的最有效方法之一,阐述了智能型混凝试验搅拌器的设计原理和技术性能.     

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     

纳米生态基对水产养殖污水的处理效果

采用三因子四水平的正交设计,实验研究了纳米生态基在不同温度、溶解氧和水力停留时间下对水产养殖污水的处理效果,确定了纳米生态基处理养殖污水的最佳条件。结果表明,含氨氮和亚硝氮浓度较高的模拟养殖污水用纳米生态基挂膜,所需时间约为22 d。纳米生态基对氨氮的去除效果明显,平均去除率达到93.5%。对氨氮去除率的影响程度,水力停留时间>温度>溶解氧。当温度为30℃,DO为5.43 mg/L,HRT为0.33 h时,纳米生态基对氨氮的处理能力最佳,去除率达到94.6%。纳米生态基对亚硝氮的平均去除率为69.3%。对亚硝氮去除率的影响程度,水力停留时间>溶解氧>温度。当温度为21℃,DO为6.40 mg/L,HRT为0.33 h时,纳米生态基对亚硝氮的处理能力最佳,去除率为71.5%。纳米生态基处理养殖污水的最佳条件:温度为30℃,DO为6.40 mg/L,HRT为0.33 h。     

Nature of the field-to-field distribution of pesticide residues

The supervised trial datasets (1950), consisting of a minimum of five residue values and selected by the experts of FAO/WHO Joint Meeting on Pesticide Residues for recommending maximum residue levels between 1997 and 2011, were evaluated to obtain information on the typical spread of residue values in individual datasets. The typical relative standard deviation, CV, of field-to-field variation of pesticide residues was about 80%. The spread of residues in datasets is independent from the chemical structure of pesticides, residue level, pre-harvest interval and number of values in the datasets. The CV ranges within the Codex commodity groups and between groups overlapped and their difference were not statistically significant. The number of residues below the limit of quantification (LOQ) affects the CV at various extents depending on the ratio of LOQ/R _mean. The combined uncertainty of the highest residue in a dataset significantly affects the CV of the dataset. The lowest and intermediate ones have less influence. The residues in different fields receiving the same treatment vary within large range: 55%, 72%, 78%, 86% and 89% of the 25,766 residues values were, respectively, within 3, 4, 5, 6 and 7 times the median value of the corresponding dataset.     

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.     

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.     

3种污泥对磺胺二甲基嘧啶的吸附性能

研究了厌氧颗粒污泥、厌氧污泥及好氧污泥对磺胺二甲基嘧啶(SM2)的吸附性能。当SM2初始浓度为50μg/L时,采用活性污泥灭活吸附,考察了吸附平衡时间、吸附等温线及温度对污泥吸附的影响,并比较了失活污泥与活性污泥的吸附性能。结果表明,3种污泥对SM2的吸附均在1 h内达到吸附平衡;3种失活污泥对SM2的吸附都可用Freundl-ich和Langmuir吸附模型来描述,并且Freundlich吸附模型的拟合效果要好于Langmuir模型(R2F>R2L);温度对3种污泥吸附影响规律一致,并且吸附常数KF(15℃)>KF(25℃)>KF(35℃),这说明吸附为放热反应,低温有利于吸附反应的进行。活性污泥对SM2的吸附与失活污泥吸附规律一致,都符合Freundlich模型。3种活性污泥对SM2的去除是吸附和降解的共同作用,并且都是降解占主导地位,降解效率为厌氧污泥>好氧污泥>厌氧颗粒污泥。     

Effect of the cationic composition of sorption solution on the quantification of sorption-desorption parameters of heavy metals in soils

We obtained the sorption isotherms of Cd, Cu, Pb and Zn in clay, clay saline and organic soils. The distribution coefficients (K(d)) were determined in 0.02 eq l(-1) CaCl(2) and in a solution that simulated the soil solution cationic composition. The K(d) values greatly varied with the composition of the sorption solution and the initial metal concentration. The sorption experiments were complemented with the quantification of the extractable metal, to estimate the reversibility of metal sorption. The extraction yields depended on the metal-soil combination, and the initial metal concentration, showing no correlation with previous K(d) values. The effect of the solution composition in mobility predictions was estimated through a Retention Factor, defined as the ratio of the K(d) versus the extraction yield. Results showed that risk was over- or underestimated using the CaCl(2) medium in soils with a markedly different soil solution composition.     

市政污泥强化脱水实验研究

通过对市政污泥进行超声处理、絮凝剂处理和超声结合絮凝剂处理,研究不同条件下污泥上清液的COD浓度、粒度分布及微观结构变化情况。实验结果表明,超声波作用可以调整污泥结构,改善污泥脱水性能;当超声时间达到20min左右时,脱水效果最好为87.9%;超声波作用使污泥中释放的COD浓度增加至91.2 mg/L;污泥颗粒粒度发生变化,分布在易脱水段10～100μm的更多。     

Kinetics and mechanisms of radiation-induced degradation of acetochlor

The radiation-induced degradation of acetochlor was investigated in this work. In a mixed solvent composed of acetonitrile and water at a ratio of 20/80 in volume, the acetochlor degradation rate was proportional to the radiation dose rate and acetochlor concentration. The acetochlor degradation efficiency was higher under alkali conditions and lower under acidic conditions. The contribution to the acetochlor degradation by the radicals was in the order of: e(aq)->.OH>H.. The quantum efficiency ratios of .OH, e(aq)- and H. for the degradation of acetochlor were calculated as 1:3:1.     

Effects of bensulfuron-methyl and cinosulfuron on growth of four freshwater species of phytoplankton

The acute toxicity of sulfonylurea herbicides bensulfuron-methyl and cinosulfuron was tested on the five species of freshwater phytoplankton: Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris and Chlorella saccharophila. Herbicide concentrations eliciting a 50% growth reduction over 96 h (EC50) ranged from 8 to 104 mg/l for cinosulfuron and from 0.015 to 6.2 mg/l for bensulfuron-methyl. The pesticides bensulfuron-methyl, atrazine and benthiocarb were more toxic than cinosulfuron, chlorsulfuron, molinate, fenitrothion and pyridaphenthion in a toxicity study with the same algal species. The transformation of effective concentrations of bensulfuron-methyl and cinosulfuron and other pesticides, obtained from toxicity measurements, into percent of the saturation level in water is used as a first evaluation of potential hazard to aquatic systems. The herbicides cinosulfuron, methyl-bensulfuron, atrazine and chlorsulfuron were more dangerous than the herbicides benthiocarb and molinate and than the insecticides fenitrothion and pyridaphenthion, in a study of hazard evaluation. The two species of Chlorella were more tolerant to both herbicides than the two species of Scenedesmus. A potential environmental hazard of sulfonylurea herbicides to aquatic systems has to be expected even at low environmental concentrations.     

染整废水处理工程设计

采用“生物接触氧化 +混凝气浮 +生物炭”工艺处理染整废水 ,COD去除率可达到 90 %以上 ,工程实践表明 ,该工艺处理效果好 ,运行稳定 ,投资省 ,处理后出水可达标排放     

Application of Markov model to environmental fate of phenanthrene in Lanzhou Reach of Yellow River

The theory of Markov Chain is used scientifically to describe the transfer/transformation of phenanthrene in Lanzhou Reach of Yellow River. In Markov Model (MM), the states of phenanthrene in Lanzhou Reach are divided into six different states, namely being degraded, leaving the system with the addvective flow, being in air, being in water, being adsorbed on suspending substances (SS), and being in bottom sediment (BS). The MM is simulated by using Matlab6.5 to reveal the temporal changes and environmental fate of phenanthrene in Lanzhou Reach. It is shown that the environmental system will be steady in 30,000-35,000 h, the final distributions of phenanthrene in air, water, SS, and BS are 23,033 kg, 1961 kg, 800 kg, and 2824 kg respectively, with the corresponding percent of 80%, 7%, 3%, and 10%.The results of MM are approximate to the results of Fugacity Model (FM), so Markov Chain can be used to evaluate the environmental fate of pollutants in multimedia environment. The outputs of MM include the following aspects: (1) The residual time of pollutant in different environmental media and the transiting time of pollutant between different environmental media; (2) The response time of the environmental system; (3) The total mass of pollutant transferred or degraded during a given time interval; (4) The time needed for the environmental system to be steady and the final steady distributions of pollutant in the environmental system.     

Measurement of Ambient Ground-Level Concentrations of Hydrogen Fluoride

The use of published, accepted methods for measuring ambient levels of gaseous hydrogen fluoride (HF) with a double-tape sampler led to large errors. The major source of error was found to be scrubbing In the stainless steel intake, which was avoided by substituting Teflon for the stainless steel. To avoid this and other problems encountered in the measurement of HF, we revised the double-tape sampler method and modified the double-tape sampler. We designed and constructed an HF calibrator for use in testing the revised method and modified sampler In the field and laboratory.

The results of a round robin indicated that, in the laboratory, the revised method has a single-operator precision of 3 percent at 2.6 μg/m³ and a between-laboratory precision of 4 percent. The average bias at 2.6 μg/m³ was 0.02 μg/m³ and was not significantly different from zero. Comparable precision and accuracy were obtained in the field. The response was linear, at least to 10 μg/m³. The limit of detectability, which appears to be limited by the variability in measurements of blank tapes, is 0.07 μg/m³. The revised method appears both precise and accurate.     

利用复合添加剂研制免烧免蒸粉煤灰砖

论述了利用复合添加剂生产免烧免蒸粉煤灰砖的制造技术，并采用模糊数学和正交试验法求出最佳工艺参数。试验表明该项新技术生产的粉煤灰砖具有强度大、抗冻性与耐水性好及成本低等优点。     

Evaluation of fecal pollution of river sediment by detection of urobilin

In this study, we attempted to establish a new indicator for fecal pollution of river sediment using a sensitive detection method for urobilin. Urobilin contained in sediment was extracted with an alkaline buffer solution. The suitable buffer solution for extraction of urobilin consisted of 0.1 M Tris-HCl buffer (pH 10.0) containing 0.1 m sodium chloride. The ratio of sediment to buffer was 1:10. The distribution of urobilin in river sediment was studied by this method. The amount of urobilin in the river sediment of Tokyo (urban) and the Miura peninsula (rural) area was surveyed. Large quantities of urobilin were detected in the sediments of the urban rivers, but it was scarce in the rural rivers. Urobilin showed a higher content in sediment than in water. Urobilin in river sediment is distributed in large amounts in the lower reaches, where the water is polluted with domestic sewage and industrial waste, but is scarce in the upper streams. The amount of urobilin decreases to the lower layers.     

Evaluation of factors influencing root-induced changes of copper fractionation in rhizosphere of a calcareous soil

Major factors influencing the root-induced copper fractionation changes within the rhizosphere of maize, wheat, pea, and soybean seedlings were evaluated using a contaminated calcareous soil. The effects of acidification, alkalization, and introduction of root exudates were investigated by addition of acid, alkaline and root exudates from solution cultures, prior to incubation and copper fractionation. Raw and sterilized soils were compared for changes of copper fractionation in the rhizosphere using rhizoboxes with maize, wheat, pea and soybean seedlings. The results indicated that the general trend in considerable changes was similar among the plant species studied. The rhizosphere experienced a depletion of carbonate associated and organic bound copper along with an accumulation of exchangeable and Fe-Mn oxide bound copper. The resulting significant influence of root exudates on copper fractionation appears to have been produced through complexation rather than acidification or alkalization. The increase in exchangeable copper in rhizosphere was strengthened by microorganisms.     

Effects of bromide on the formation of THMs and HAAs

The role of bromide in the formation and speciation of disinfection by-products (DBPs) during chlorination was investigated. The molar ratio of applied chlorine to bromide is an important factor in the formation and speciation of trihalomethanes (THMs) and halogenacetic acids (HAAs). A good relationship exists between the molar fractions of THMs and the bromide incorporation factor. The halogen substitution ability of HOBr and HOCl during the formation of THMs and HAAs can be determined based on probability theory. The formation of HAAs, and their respective concentrations, can also be estimated through use of the developed model.     

杀灭菊酯对鲤鱼血液影响初探

报道了杀灭菊酯杀虫剂对鲤鱼的血液系统的影响，结果表明，（１）杀灭菊酯引起鲤鱼血浆中离子浓度发生明显改变，Ｎａ＾＋下降１０％～２０％，Ｋ＾＋下降１０％～３５％，其它离子如Ｃｌ＾－，Ｃａ＾２＋，磷等则升高；同时还观察到Ｈｂ保持不变，（２）杀灭菊酯使ＲＢＣ渗透脆性增加，在体和体外处理均能引起ＲＢＣ破损，产生溶血，这很可能是杀灭菊酯对鱼类高毒的非神经作用的重要致毒原因之一。