遥感在环境影响评价中的应用——以大清公路为例

本文以遥感为技术手段,利用ERl、ASⅢAGINE8.5和FRAGSTATS3.3软件针对项目区在景观总体格局和各类型斑块两个层次计算出十几种景观指数,对该区域的景观格局分布做出了较为全面的定量分析.结果表明:草地景观面积最大,斑块数最多,是评价区的基质.乔木林地在各项指数分析中均较低.文中探讨了遥感与地面调查的优缺点,得出结论:以遥感技术为手段,结合地面调查是评价区域生态环境的有效工具.     

电化学法生成Fenton试剂及其在工业染料废水降解脱色中的应用

以多孔石墨电极为阴极 ,电解时在阴极通以氧气或空气 ,电解生成的过氧化氢与阳极溶解的Fe2 +进行随后化学反应 ,现场生成羟基自由基 (Fenton试剂 ) ,进而对有机染整工业废水进行降解脱色反应。以可见光吸收谱图表征了工业染料废水经电解槽处理后吸光度的变化 ,以重铬酸钾法测试染料处理后的COD。实验结果表明 ,COD的去除率大于 80 % ,染料的脱色率达 1 0 0 % ,若将电解电流密度控制在 1 0mA/cm2 以下 ,槽电压可控制在 5V以内。实验结果表明 ,向阴极多孔石墨电极中通入空气与通入氧气的效果一致。     

A review of source tracking techniques for fine sediment within a catchment

Excessive transport of fine sediment, and its associated pollutants, can cause detrimental impacts in aquatic environments. It is therefore important to perform accurate sediment source apportionment to identify hot spots of soil erosion. Various tracers have been adopted, often in combination, to identify sediment source type and its spatial origin; these include fallout radionuclides, geochemical tracers, mineral magnetic properties and bulk and compound-specific stable isotopes. In this review, the applicability of these techniques to particular settings and their advantages and limitations are reviewed. By synthesizing existing approaches, that make use of multiple tracers in combination with measured changes of channel geomorphological attributes, an integrated analysis of tracer profiles in deposited sediments in lakes and reservoirs can be made. Through a multi-scale approach for fine sediment tracking, temporal changes in soil erosion and sediment load can be reconstructed and the consequences of changing catchment practices evaluated. We recommend that long-term, as well as short-term, monitoring of riverine fine sediment and corresponding surface and subsurface sources at nested sites within a catchment are essential. Such monitoring will inform the development and validation of models for predicting dynamics of fine sediment transport as a function of hydro-climatic and geomorphological controls. We highlight that the need for monitoring is particularly important for hilly catchments with complex and changing land use. We recommend that research should be prioritized for sloping farmland-dominated catchments.     

Water quality evaluation of Haihe River with fuzzy similarity measure methods

Fuzzy similarity measures, which are used to judge the closeness of two fuzzy sets, are presented to evaluate the water quality of the Haihe River. Based on the membership functions and coefficient of variation as the weights, four fuzzy similarity measures （including Lattice similarity measure, Hamming similarity measure, Euclidean similarity measure and the max-min similarity measure） are used to classify the 299 samples into the proper water quality standard ranks. The results are compared with the traditional distance discriminant methods. The calculation of two traditional distance discriminant methods （both Euclidean distance and absolute value distance） is also based on the use of coefficients of variation as the weights. Without the Lattice similarity measure, for this method loses some information, the correct assignment of samples classified into the same water quality ranks is 75.92% with the other three similarity measures and two distance discriminant methods. This result shows the reliability of the five methods. Only considering the three similarity measures, there were only 1.01% of the samples that did not classify to the same ranks, while the corresponding ratio of the two distance discriminant methods was 5.69%. The results of leave-one-out cross validation show that more than 88% of the samples are classified to the proper ranks, which demonstrates that the similarity measures are suitable to evaluate the water quality of the Haihe River.     

锯末+乙醇作为混合碳源去除地下水中硝酸盐的影响因素研究

本试验采用室内试验装置,研究了 pH、温度、硝酸盐浓度对锯末+乙醇作为混合碳源去除地下水中硝酸盐的影响结果表明,pH值在5～10内变化时对锯末+乙醇混合碳源体系的硝酸盐去除率影响较大,pH ＞7时的硝酸盐去除率明显高于pH ＜7时的去除率;并且随着pH值的增加,亚硝酸盐的积累量越多,锯末+乙醇混合碳源体系最佳的pH值范围是7～8.锯末+乙醇混合碳源体系受温度的影响较大,温度为8.5、15℃时的反硝化速率显著低于25℃时的速率,25℃时的反硝化速率分别是8.5、15℃时的3倍和1.5倍,锯末+乙醇混合碳源体系适宜的温度范围为25 ～35℃进水硝酸盐浓度也会影响锯末+乙醇混合碳源体系的反硝化效果,硝酸盐氮浓度在67.8 ～113 mg·L-1范围内变化时,反应体系的硝酸盐去除效果较好反应初期,硝酸盐浓度越大混合碳源体系的反硝化速率就越低,可能较大的硝酸盐负荷对反硝化细菌产生毒害作用而不利于硝酸盐的去除.     

紫外活化过硫酸盐降解二苯甲酮-4的动力学影响及降解机理与风险评价

活化PS（过硫酸盐）氧化工艺对于降解水中新兴微污染物具有潜在应用价值.为研究活化PS体系对BPs（二苯甲酮类）有机防晒剂的降解性能,以BP4（二苯甲酮-4）为研究对象,采用UV/PS（紫外活化过硫酸盐）工艺降解BP4,比较单一UV、单一PS和UV/PS 3种工艺对BP4的去除效果,考察各因素对UV/PS工艺去除BP4动力学的影响,同时探究BP4降解机理并进行风险评价.结果表明:BP4降解过程符合准一级反应动力学模型;最佳PS投加量为1.0 mmol/L,反应30 min后BP4去除率可达94%,增加PS投加量或降低初始c（BP4）均可促进BP4降解,无机阴离子（HCO₃-和Cl-）对BP4降解均有抑制作用,酸性条件有利于BP4降解;基于HPLC-MS/MS鉴定出8种中间产物,并提出降解路径,费氏弧菌毒性试验和ECOSAR v1.10软件预测表明,UV/PS工艺降解BP4过程中生成的中间产物比母物质毒性更高.研究显示,UV/PS工艺可有效去除BP4,但其中间产物可能会造成潜在的生态风险,后续需进一步深入研究.      

栾树对湘潭锰尾矿土不同处理方式下植被修复盆栽实验

锰矿废弃地植被修复可促进矿区生态环境的改善和经济的可持续发展,植被修复方法和技术措施对锰矿废弃地的修复至关重要,混合基质中尾泥和尾渣的配置比例与配置方式也是提高植物存活率的关键技术措施.本研究采用栾树进行锰矿废弃物(尾泥和尾渣)盆栽试验,探讨不同混合比例处理方式下锰尾矿废弃物的特性以及栾树对重金属锰的植物修复效果.结果表明:(1)锰矿尾泥呈酸性,尾渣呈碱性,尾渣中全Mn和有效Mn含量高于尾泥,二者混合基质的p H值和全Mn含量则随着尾渣含量所占比例的增加而升高,但有效Mn含量则逐渐降低.(2)不同比例的尾泥和尾渣混合基质可以有效改善土壤的物理性质,提高栾树的存活率和改善植物的生长状况;随尾泥含量的增加,栾树总生物量增多,生产力提高,当V(尾渣)∶V(尾泥)=3∶1时的栾树生产力与对照土壤中的栾树生产力相当.(3)从栾树各器官的Mn富集量、生物富集系数和转移系数来看,栾树不属于Mn超富集植物,但作为Mn的低积累植物,属于Mn的耐性树种,具有较强的适应性,可用于锰矿废弃地的植物稳定修复.     

Development of a method for comprehensive water quality forecasting and its application in Miyun reservoir of Beijing, China

Water quality forecasting is an essential part of water resource management. Spatiotemporal variations of water quality and their inherent constraints make it very complex. This study explored a data-based method for short-term water quality forecasting. Prediction of water quality indicators including dissolved oxygen, chemical oxygen demand by KMnO₄ and ammonia nitrogen using support vector machine was taken as inputs of the particle swarm algorithm based optimal wavelet neural network to forecast the whole status index of water quality. Gubeikou monitoring section of Miyun reservoir in Beijing, China was taken as the study case to examine effectiveness of this approach. The experiment results also revealed that the proposed model has advantages of stability and time reduction in comparison with other data-driven models including traditional BP neural network model, wavelet neural network model and Gradient Boosting Decision Tree model. It can be used as an effective approach to perform short-term comprehensive water quality prediction.     

云南玉溪烟区轮作与连作土壤细菌群落多样性比较研究

为评价云南玉溪烟区轮作和连作对土壤细菌群落多样性影响,从土壤中直接提取土壤细菌总DNA,用细菌16S rDNA特异性引物进行PCR扩增和变性梯度凝胶电泳(DGGE),每个处理样品3次重复,在DGGE图谱中相似性较高,基本聚在一起,从整体证明了试验操作方法较为精确.从泳道分析图可知,轮作土壤细菌群落各泳道条带数量13～29条不等,平均为21条.连作土壤细菌群落各泳道条带数量从4～20条不等,平均为12条.从每条泳道的条带数方面和光密度值分别进行细菌群落多样性各指标的比较,结果表明,轮作处理细菌群落丰富度指数均大于连作处理,轮作香农-威纳和辛普森指数(1/D)均大于连作,表明轮作微生物多样性较连作高,轮作方式可以提高植烟土壤细菌群落的多样性.     

Adaptive neuro fuzzy inference system for classification of water quality status

An adaptive neuro fuzzy inference system was used for classifying water quality status of river. It applied several physical and inorganic chemical indicators including dissolved oxygen, chemical oxygen demand, and ammonia-nitrogen. A data set (nine weeks, total 845 observations) was collected from 100 monitoring stations in all major river basins in China and used for training and validating the model. Up to 89.59% of the data could be correctly classified using this model. Such performance was more competitive when compared with artificial neural networks. It is applicable in evaluation and classification of water quality status.