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重金属污染胁迫下盐肤木的生化效应及波谱特征 总被引：11，自引：1，他引：10
利用遥感生物地球化学的原理和方法,分析了德兴铜矿的重金属污染状况和植物盐肤木的生物地球化学效应,对盐肤木生物地球化学效应的波谱特征进行了系统的提取和分析.研究发现酸、铜、镉等是德兴铜矿地区主要的环境污染因子,野外调查及样品的化验分析表明盐肤木对铜元素呈现一定的富集作用和很强的位移效应,是适合铜矿复垦的植被.利用导数光谱、包络线去除、红边效应、植被指数等光谱信息处理方法对盐肤木的野外波谱分析表明,随着叶片中Cu等金属元素含量的增大,其产生的毒化效应的波谱特征越明显,盐肤木叶片光谱反射率明显升高,波形蓝移,红边陡坡斜率增大,叶绿素吸收深度变浅,吸收中心稍有蓝移,水的吸收深度变浅,吸收中心位置红移,绿度指数变化明显.对波谱特征及其与重金属含量的相关关系综合分析后认为,红边特征、植被指数NDVI、叶绿素吸收深度与叶片铜含量关系显著,可以作为植被铜污染遥感图像特征提取的参考. 相似文献
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Mineral extraction and processing, especially metal mining, produces crushed and milled waste; such material, exposed to weathering, poses the potential threat of environmental contamination. In this study, mill tailings from inactive Pb-Zn mines in New Mexico, southwest USA, have been examined for their potential environmental impacts by means of detailed mineralogical and geochemical characterization. The principal ore minerals remaining in the tailings material are sphalerite, chalcopyrite, and very minor galena, smithsonite, and cerrusite, accompanied by the gangue minerals pyrite, pyrrhotite, magnetite, hematite, garnet, pyroxene, quartz, and calcite. White precipitate occurring on tailings surfaces is composed of gypsum and hydrated magnesium sulfates. Pyrite is mostly unaltered or shows only micron-scale rims of oxidation (goethite/hematite) in some surface samples. This iron oxide rim on pyrite is the only indication of weathering-derived minerals found by microscopy. There are variations in element concentrations with depth that reflect primary variations through time as the tailings ponds were filled. Cadmium and Zn concentrations increase with depth and Ag and Pb are low for the uppermost core samples, while Cu, Ni, and Co concentrations are generally high for the uppermost core samples. These elemental distributions indicate that little or no leaching has taken place since emplacement of the tailings because no accumulation or enrichment of these metals is observed in Hanover tailings, even in reducing portions of tailings piles. Element concentrations of surface samples surrounding the tailings reflect underlying mineralized zones rather than tailings-derived soil contamination. We observed no successive decreasing metal concentrations in prevalent wind directions away from the tailings. Stream sediment samples from Hanover Creek have somewhat elevated Zn, Cd, and Pb concentrations in areas that receive sediments from erosion of the tailings. However, input from tributaries downstream of the ponds appears to be principal source of heavy metals in Hanover Creek. The results of this study indicate that there is low risk for groundwater heavy-metal contamination from Hanover tailings. Tailings material do not show significant geochemical oxidation/alteration or metal leaching with depth. Our studies indicate that neutralizing minerals present in the tailings are sufficient to keep the tailings material chemically stable. Geochemically, however, tailings materials are being eroded and may pose a threat to Hanover Creek via siltation. 相似文献
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Vanessa Mathews 《Urban geography》2013,34(3):337-356
This paper traces one craft brewery (Mill Street Brewery) across two industrial heritage properties—in Toronto’s Distillery District and Ottawa’s LeBreton Flats—to investigate the extent to which alcohol functions as a catalyst of urban change. Using an analysis of both planning and policy documents, as well as media coverage for the two properties, we explore the role that alcohol plays in recalibrating industrial landscapes into spaces of consumption, and the potential for craft breweries to alter the meanings of industrial heritage. We argue that craft beer works as a vehicle in the manufacture of new spaces of cultural consumption. Specifically, craft beer production and consumption are used to aestheticize the industrial past and pacify resistance to central-city gentrification. 相似文献
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Terrain influences many ecological processes. Therefore, ecologists must consider terrain effects in sampling designs. Incomplete information on the ecological role of terrain, however, makes it difficult to account for terrain variability in sample designs. As a partial solution, we introduce a protocol that automatically stratifies complex terrain. This stratification method uses image-processing techniques to cluster digital images of slope, elevation, and aspect into homogeneous groupings. The technique is demonstrated for a stratification of complex terrain disturbed by a large forest fire. By identifying terrain complexity at several spatial resolutions, we were able to place transects that sample terrain variability and fire severity representatively across a controlled range of scales. [Key words: terrain, stratification, image processing, sample design.] 相似文献
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林叔忠 《地球科学与环境学报》1994,(1)
本文介绍了高压喷射灌浆技术在北江大堤强透水堤基处理中的应用．文中在分析堤基地层结构特征和物性指标的基础上，论述了高喷防渗墙的设计施工参数，根据已有围井检验结果，分析了各种地层高喷防渗墙的防渗效果，提出了用“单位渗水率”指标评价围封质量的新方法．文中根据大堤渗流观测资料和检验指标“单位渗水率”，建立了高喷防渗墙垂直截流堤基的渗流计算公式，并得出高喷防渗墙能有效地抑制住大堤堤基的渗流形变． 相似文献
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In this paper we assess the ways in which the topography of glaciated northern Britain has affected the siting and operations of water mills, and compare those factors and mill locations for mills in unglaciated southern Britain. We then explore the impacts of these findings on the potential downstream impacts of mill dam failure.We used a GIS to plot the locations of all 1712 localities in Britain's Ordnance Survey Gazetteer that include “mill”, “milton” (‘milltown’) and “miln” in their name. We then examined the geomorphology of mill locations in two study areas, one in northeast Scotland (glaciated; 421 localities) and one in southern England (unglaciated; 438 localities), assessing (i) mill location within the drainage net, and (ii) the steepness of an adjacent stream within a radius of 500 m of the mill locality. The large majority of mills are located within the first 10 km of the drainage net in both study areas, presumably on relatively stable bedrock channels. The data for most of the mills in both study areas indicate that catchment areas of less than 200 km2 are sufficient to supply the water necessary for operation of a mill, but the higher rainfalls and runoff in Scotland (almost twice the values in the England study area) mean that mill dams in S England must have been higher and of higher capacity than those in NE Scotland. That finding is consistent with the results related to channel steepness, which show that mills in Scotland are associated with steeper channels than is the case in England. The generally greater channel steepness in Scotland (and the greater downstream extent of those steeper channels, as also confirmed by the data) reflect both the many glacially steepened bedrock channel reaches in Scotland and the steepening of Scotland's coastal bedrock channels as a result of glacio-isostatic rebound.The technical requirements of water mill operation favour situations where water can be delivered to the top of, or at least part-way up, the mill wheel. Scotland's steeper rivers and its higher rainfalls mean that Scotland's mills require smaller mill dams, if they are needed at all. It would therefore be expected that catastrophic or managed failure of mill dam walls in northern Britain would release lower volumes of trapped sediment to the downstream fluvial system. These lower volumes would in turn result in lower geomorphological impacts downstream of the dam, both in terms of changing channel patterns and burial of the bed. Such dam failure is a key current issue in geomorphology and one case study of a small failed mill dam in western Scotland confirms the minimal downstream impacts of that failure. 相似文献
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Field experiments were conducted to investigate the effects of leaf area index and soil moisture content on evapotranspiration and its components within an apple orchard in northwest China for 2 years. Evapotranspiration in the non‐rainfall period was estimated using two approaches: the soil water balance method based on tube‐type time‐domain reflection measurements, and sap flow plus micro‐lysimeter methods. The two methods were in good agreement, with differences usually less than 10%. The components of evapotranspiration varied with canopy development. During spring and autumn, soil evaporation was dominating as result of low leaf area index. In summer, plant transpiration became significant, with an average transpiration to evapotranspiration ratio of 0·87. The crop coefficient Kc showed a strong linear dependence on leaf area index. The water stress coefficient Ks was around 1·0 when soil moisture was above 23% and started to decrease linearly after that. This study demonstrates that prediction of evapotranspiration in apple orchards can be made using the Food and Agriculture Organization's crop coefficient method from commonly available meteorological data in the area. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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本文以云南省蒙自市断陷盆地高原面上典型封闭式岩溶洼地小流域为研究对象,研究小降雨事件对土壤水分及植物水势的影响。结果表明:（1）在研究区内小降雨事件一般只能补给10 cm以上的土壤,因此在旱季（强降雨事件发生前）,土壤水分随着深度的增加整体呈变小的趋势;受洼地地形影响,整个土壤剖面（0 ~ 80 cm）的土壤水分存在从坡顶到洼地底部逐渐增加,苹果树叶水势逐渐升高的现象;受地质背景的影响,土石质坡地平均土壤水分比石质坡地土壤水分高2.67%,相对应的土石质坡地苹果树受干旱胁迫的程度要低于石质坡地。（2）通过观测对比发现,8天内12次的小降雨事件可以使0~10 cm土壤水分整体上略有升高,但并未能完全改变0~10 cm土壤水分洼地底部大于两侧坡地,而土石质坡地高于石质坡地的特征。（3）小降雨事件虽然只能补给0~10 cm的土壤水分,但由于坡地地区苹果树根系分布较浅（5~30 cm）,部分浅层分布的苹果树根系已能吸收到水分,另一方面小降雨事件具有降温、增湿,减少太阳辐射的作用,可以减小苹果树蒸腾作用,从而降低苹果树叶水势,因此推测小雨事件可以明显减轻苹果树受干旱胁迫的程度 相似文献
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High-performance thin-layer chromatography with automated multiple development (AMD-HPTLC) was applied for the examination of pulp mill bleachery effluents from an alkali-oxygen-peroxide (EOP) bleaching stage of a sulfite pulp. A gradient based on methanol and dichloro-methane was developed for the separation of the effluent compounds over a wide range of migration distances. A series of reference substances such as lignin phenols and other aromatic acids, aldehydes, and alcohols as well as two resin acids were investigated in parallel using the AMD-HPTLC method. Characterization of the effluent compounds was possible using the migration distances and the recorded spectra. The composition of different samples of effluent were found to be very similar. The application of the AMD-HPTLC to effluent fractions from acidic liquid-liquid extraction using diethyl ether and from RP C18 solid-phase extraction allowed us to follow the behaviour of the effluent compounds in the extraction procedure. 相似文献
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