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731.
大庆油田化工总厂废水中化学需氧量(COD)的测定采用库仑法。为了提高质控合格率,从人员素质、仪器设备、电级内液等9个方面分析寻找导致误差的主要影响因素并制定对策。同时对影响电极内液及消解的因素进行正交实验确定最佳条件。结果使库仑法质控合格率由90%提高到95%,测定38次标样全部合格。  相似文献   
732.
2 /yr, respectively. Geomorphic evidence indicates that plantation agriculture during the 18th and 19th centuries did not cause severe erosion. Since about 1950 there has been rapid growth in roads and development due to increasing tourism and second-home development. Our field investigations identified the approximately 50 km of unpaved roads as the primary source of anthropogenic sediment. Field measurements of the road network in two catchments led to the development of a vector-based GIS model to predict road surface erosion and sediment delivery. We estimate that road erosion has caused at least a fourfold increase in island-wide sediment yields and that current sedimentation rates are unprecedented. Paving the dirt roads and implementing standard sediment control practices can greatly reduce current sediment yields and possible adverse effects on the marine ecosystems surrounding St. John.  相似文献   
733.
/ The risk tropospheric ozone poses to forests in the United States is dependent on the variation in ozone exposure across the distribution of the forests in question and the various environmental and climate factors predominant in the region. All these factors have a spatial nature, and consequently an approach to characterization of ozone risk is presented that places ozone exposure-response functions for species as seedlings and model-simulated tree and stand responses in a spatial context using a geographical information systems (GIS). The GIS is used to aggregate factors considered important in a risk characterization, including: (1) estimated ozone exposures over forested regions, (2) measures of ozone effects on species' and stand growth, and (3) spatially distributed environmental, genetic, and exposure influences on species' response to ozone. The GIS-based risk characterization provides an estimation of the extent and magnitude of the potential ozone impact on forests. A preliminary risk characterization demonstrating this approach considered only the eastern United States and only the limited empirical data quantifying the effect of ozone exposures on forest tree species as seedlings. The area-weighted response of the annual seedling biomass loss formed the basis for a sensitivity ranking: sensitive-aspen and black cherry (14%-33% biomass loss over 50% of their distribution); moderately sensitive-tulip popular, loblolly pine, eastern white pine, and sugar maple (5%-13% biomass loss); insensitive-Virginia pine and red maple (0%-1% loss). In the future, the GIS-based risk characterization will include process-based model simulations of the three- to 5-year growth response of individual species as large trees with relevant environmental interactions and model simulated response of mixed stands. The interactive nature of GIS provides a tool to explore consequences of the range of climate conditions across a species' distribution, forest management practices, changing ozone precursors, regulatory control strategies, and other factors influencing the spatial distribution of ozone over time as more information becomes available.KEY WORDS: Ecological risk assessment; GIS; Ozone; Risk characterization; Forests; Trees  相似文献   
734.
新型混凝剂SLB的制备及应用   总被引:4,自引:0,他引:4  
新型混凝剂SLB是将聚铝和阳离子改性淀粉在一定条件下直接复配而成的一种无机-有机复合型混凝剂,通过对炼油厂及钠土污水的混凝处理实验,反映出SLB具有较好的净化效果。此外,SLB原料易得,成本低,有广阔的应用前景。  相似文献   
735.
本文在综述四川酸性降水范围、发展趋势预测的基础上,根据野外调查、现场考察和有关资料,阐述了酸雨形成的多种污染源及其对农业生态系统的危害。着重分析和论证了酸沉降(含酸雨、酸雾)对农作蔬菜的影响,并对酸沉降形成的主要几种污染影响范围和造成的经济损失采用分项估算法。估算公式为:S农损=D粮损×g×J+E蔬损×g×J+F油损×g×J,式中D、E、F分别代表粮食、蔬菜、油菜受酸沉降污染危害影响面积,g为每亩面积减产数量,J为单位产量价格。根据公式估算,经济损失为059-066亿元/年,取平均值≈S农损,总共为063亿元/年。  相似文献   
736.
矿井通风系统模糊可靠性研究   总被引:2,自引:1,他引:2  
定义模糊可靠度为一个服从正态分布的模糊数,并以模糊数作为通风系统的各风路可靠度,进而提出了矿井通风系统的模糊可靠度计算方法。同时在置信水平上,确定矿井通风系统的普通可靠度置信区间。若=1,则模糊可靠度计算转化为可靠度计算。  相似文献   
737.
赵大传  杨厚玲 《化工环保》1996,16(6):346-350
对焦化厂蒸氨废水中的有机物进行了GC/MS分析,发现酚类,吲哚,喹啉和硫醇是主要污染物成分。对旨在降低蒸氨废水硫化物含量的各种处理方法进行了比较。采用CWZ-01吸附剂的吸附法能使废水中硫化物降至30mg/L以下。  相似文献   
738.
This article summarizes a study conducted by the U.S. Army Engineer Waterways Experiment Station to develop technical information and to evaluate the engineering feasibility of restoration alternatives for DDT-and PCB-contaminated sediments on the Palos Verdes shelf and slope near Los Angeles, California. The study evaluated the nonremoval alternative of in-place capping of contaminated sediments on the shelf and slope; removal of contaminated sediments using conventional and specialized dredging equipment and deep ocean mining equipment; treatment of contaminated sediments; and disposal of contaminated sediments in confined (diked) disposal facilities (CDFs), contained aquatic disposal (CAD) sites, upland landfills, and deep ocean basin sites. Cost estimates of the various alternatives were also prepared. This article concludes that restoration of the contaminated sediments is technically feasible. Sediments on the shelf and slope can be removed using available dredging technologies for deep water environments. In-place capping, CAD, and CDF alternatives are technically feasible. The deep ocean basin disposal alternative is not feasible from the technical or regulatory standpoint. The treatment alternative is not feasible from the implementability and economic standpoint.  相似文献   
739.
三峡工程移民卫生防病现状调查报告   总被引:3,自引:0,他引:3  
本文报道了三峡工程四川库区移民安置区的自然疫源性疾病,虫媒传染病,介水传染病和地方病等的目前流行态势和环境卫生状况;预测了移民过程中地潜在危险,针对存在的问题,指出加强移民的卫生防病,对保护移民健康,保障移民工作顺利进行了是十分重要的。  相似文献   
740.
本文按时段和随机采集了三峡库区降雨径流水体样品,测定了水体中Cu、Mn、Ni、Zn、Pb含量,统计结果表明:Mn、Zn、Pb在径流水体中的含量趋于平均,变异系数较小。随产流时间的变化,水体中5种元素的变化规律不明显  相似文献   
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