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111.
Felipe Hernndez‐Luis Mercedes Lemus Domingo Grandoso Mario V. Vzquez Carmen D. Arbelo 《补救:环境净化治理成本、技术与工艺杂志》2004,14(3):105-112
This article presents the results of an experimental study conducted to evaluate the behavior of two types of andisol soils found in Tenerife, Canary Islands, Spain. The soils were evaluated in relation to their buffering capacity when confronted with acid and alkaline fronts generated during electroremediation treatment. The study was conducted using a cell, which established a continuous flow of distilled water through electrode chambers to remove H+ and OH? generated during electrolysis. The results indicate that the soils had sufficient buffer capacity to support variations in pH independent of the maintenance of flow of solution in the electrode chambers. Although the mechanism of migration was not affected, the flow of water favored the movement of ions by diffusion monitoring of the electrolytic current allowed for a real‐time parameter to act as an indicator of the quantity of ions available in regions near the electrodes. © 2004 Wiley Periodicals, Inc. 相似文献
112.
新疆草地资源特征与生态治理 总被引:9,自引:0,他引:9
从新疆草地资源发生条件分析其多样性,对草地退化进行了生态分析,提出了草地生态恢复的生态置换理论与实施方案。 相似文献
113.
生态移民在保护自然生态环境中的重要作用及实施建议 总被引:1,自引:0,他引:1
在西部大开发中,生态环境保护与建设要先行,而生态移民则是落实该项政策的一项极重要措施。将自然保护区、交通和通讯不发达的边缘区、生态环境脆弱区和地质灾区的农牧民,移往自然环境条件较好,公路交通及通讯发达,接近城镇的地区,不但可改善和提高这些居民的生活水平,更重要的是对迁出区的自然生态环境保护,特别是珍稀野生动植物的生存和自然繁殖有十分积极的作用。而工业生产移民则是环境保护必要手段。该项政策的实施,不但具有重大社会政治、生态环境及经济效益,而且在我国自然保护史上是个重大创举。 相似文献
114.
Aida Mendez Gary R. Sands Berangere Basin Chang‐Xing Jin Paul J. Wotzka 《Journal of the American Water Resources Association》2004,40(2):385-400
ABSTRACT: Surface and subsurface drainage make crop production economically viable in much of southern Minnesota because drainage allows timely field operations and protects field crops from extended periods of flooded soil conditions. However, subsurface drainage has been shown to increase nitrate/nitrogen losses to receiving waters. When engaging in drainage activities, farmers are increasingly being asked to consider, apart from the economic profit, the environmental impact of drainage. The Agricultural Drainage and Pesticide Transport model (ADAPT) was used in this study to evaluate the impact of subsurface drainage design on the soil water balance over a two‐year period during which observed drainage discharge data were available. Twelve modeling scenarios incorporated four drainage coefficients (DC), 0.64 cm/d, 0.95 cm/d, 1.27 cm/d, and 1.91 cm/d, and three drain depths, 0.84 m, 1.15 m, and 1.45 m. The baseline condition corresponded to the drainage system specifications at the field site: a drain depth and spacing of 1.45 m and 28 m, respectively (DC of 0.64 cm/d). The results of the two‐year simulation suggested that for a given drainage coefficient, soils with the shallower drains (but equal DC) generally have less subsurface drainage and can produce more runoff (but reduced total discharge) and evapotranspiration. The results also suggested that it may be possible to design for both water/nitrate/nitrogen reduction and crop water needs. 相似文献
115.
Mario Tiscareo‐Lpez Miguel Velsquez‐Valle Jaime Salinas‐Garcia Alma Delia Bez‐Gonzlez 《Journal of the American Water Resources Association》2004,40(2):401-408
ABSTRACT: Intensive cropping systems based on mechanical movement of soil have induced land degradation in most agricultural areas due to soil erosion and soil fertility losses. Thus, farmers have been increasing fertilization rates to maintain an economically competitive crop yield. This practice has resulted in water quality degradation and lake eutrophication in many agricultural watersheds. Research was conducted in the Patzcuaro watershed in central Mexico to develop appropriate technology that prevents nonpoint source pollution from fertilizers. Organic matter (OM) and nitrogen (N) losses in runoff and nitrate (NO3‐N) percolation in Andisols with corn under conventional till (CT) and no‐till (NT) treatments using variable percentages of crop residue as soil cover were investigated for steep‐slope agriculture. USLE type runoff plots were used to collect water runoff, while suction tubes with porous caps at 30, 60, and 90 cm depth were used to sample soil water solutes for NO3‐N analyses. Results indicated a significant reduction of N and OM losses in runoff as residue cover increased in the NT treatments. Inorganic N in runoff was 25 kg/ha for NT without residue cover (NT‐0) and 6 kg/ha for the NT with 100 percent residue cover (NT‐100). Organic matter losses in runoff were 157 and 24 kg/ha for the NT‐0 and NT‐100 treatments, respectively. Nitrate‐N percolation was evident in CT and NT with 100 percent residue cover (NT‐100). However, NT‐100 had higher NO3‐N concentration at the root zone, suggesting the possibility of reducing fertilization rates with the use of NT treatments. 相似文献
116.
Feng Peng David L. Johnson Steven W. Effler 《Journal of the American Water Resources Association》2004,40(3):663-676
ABSTRACT: Individual particle analysis (IPA) by scanning electron microscopy interfaced with automated image and X‐ray analyses was used to characterize inorganic particles in five reservoirs and four tributaries located within the Catskill and Delaware systems of the New York City water supply. Individual particle analysis provides combined elemental and morphologic characterizations. Results are presented in terms of particle projected area per unit volume (PAV), consistent with optical impacts, and partitioned into seven generic particle types according to composition. Minerals of terrigenous origins, particularly clay minerals, dominated the inorganic particle populations of all the study systems except one downstream reservoir. Higher PAV levels were observed in the Catskill system. Particle dynamics represented by PAV were driven primarily by runoff, while the reservoirs were also greatly influenced by the timing of sediment resuspension promoted by drawdown of the surface and fall mixing. The benefit of the serial configuration of the reservoirs in decreasing inorganic particles with progression downstream towards the city is demonstrated. The patterns in PAV levels among the study systems generally tracked those of more common metrics of impacts of suspensoids, including mass concentrations of suspended solids, turbidity, and Secchi disc transparency. 相似文献
117.
118.
为解决皮带运输的防尘问题,通过现场调查、尘源分析、工程实验,对皮带运输设备的防尘措施进行研究,研制成密闭、无动力减压、自动加湿防尘装置,经现场试用,使作业场所空气中粉尘浓度降到国家标准以下,取得良好防尘效果. 相似文献
119.
120.
Many Superfund/hazardous chemical sites include waterbodies whose sediments contain hazardous chemicals. With the need to assess, rank, and remediate contaminated sediments at such sites, as well as in other waterways, regulators seek a simple, quantitative assessment approach that feeds easily into a decision‐making scheme. Numeric, co‐occurrence‐based “sediment quality guidelines” have emerged with the appearance of administrative simplicity. However, the very foundation of the co‐occurrence approach, based on the total concentrations of a chemical(s) in sediment, is technically invalid; its application relies on additional technically invalid presumptions. Use of technically invalid evaluation approaches renders any assessment of the significance of sediment contamination unreliable. This article reviews the technical roots and assumptions of the co‐occurrence‐based SQGs, the fundamental flaws in the rationale behind their development and application, and their misapplication for sediment quality evaluation. It also reviews concepts and approaches for the more reliable evaluation, ranking, and cleanup assessment of contaminated sediments at Superfund sites and elsewhere. © 2005 Wiley Periodicals, Inc. 相似文献