Effect of salinity on heavy metal mobility and availability in intertidal sediments of the Scheldt estuary   总被引：8，自引：0，他引：8  

G. Du Laing  R. De Vos  B. Vandecasteele  E. Lesage  F.M.G. Tack  M.G. Verloo 《Estuarine, Coastal and Shelf Science》2008,77(4):589-602

The effect of the flood water salinity on the mobility of heavy metals was studied for intertidal sediments of the Scheldt estuary (Belgium). Soils and sediments of 4 sampling sites were flooded with water of different salinities (0.5, 2.5, and 5 g NaCl L⁻¹). Metal concentrations were monitored in pore water and surface water. To study the potential effects of flood water salinity on metal bioavailability, duckweed (Lemna minor) was grown in the surface water. The salinity was found to primarily enhance the mobility of Cd and its uptake by duckweed. Cadmium concentrations in pore water of soils and sediments and surrounding surface waters significantly exceeded sanitation thresholds and quality standards during flooding of initially oxidized sediments. Moreover, the effect was observed already at lower salinities of 0.5 g NaCl L⁻¹. This implies that risks related to Cd uptake by organisms and Cd leaching to ground water are relevant when constructing flooding areas in the brackish zones of estuaries. These risks can be reduced by inducing sulphide precipitation because Cd is then immobilised as sulphide and its mobility becomes independent of flood water salinity. This could be achieved by permanently flooding the polluted sediments, because sulphates are sufficiently available in the river water of the brackish part of the estuary.  相似文献   

Study on wetland resources in deltas around Bohai Sea     

LIU Zhen-qian  LIU Hong-yu  LU Xian-guo 《中国地理科学(英文版)》2000,10(2):151-158

lINrnODUCTIONWetlandisoneoftheimPortantresourPeswiththehighestbiodiversityandproductivity.Greatenviron-mentalfunctionssuchasstabilizingclimate,controllingfloods,purifyingPOllution,providinghabitatsforcrea-tures,etc.areperformedbywetlands.Wetlandsindeltaareashavespecialecologicalpropertiesandland-scapepattems.So,itissignificanttostudythere-sourcesofwetlandslocatedindeltas.HuanghedeltaandLiaohedeltaaretwolargestdeltasaroundtheBohaiSea.TheyrepresentdeltasareundBohaiSeainpropertiesofwetlan…  相似文献   

Chemical characteristics of water environment in limnic wetlands in the western Songnen Plain, China   总被引：1，自引：1，他引：0  

SONG Xin-shan  YAN Bai-xing  DENG Wei  ZHAI Jin-liang 《中国地理科学(英文版)》2000,10(4):377-382

Duetoregionalhydrogeologicandclimaticconditions,inthewesternSongnenPlain,themostdistinctcharacteristicofwaterenvironmentinlimnicwetlandsisthatmanywaterbodieshavehighsaltcontentsandpHvalues,andsomelimnicwetlandsbelongtosaltmarshes.Thelimnicwetlandsofthisregionarespecialnaturecomplex.Itisimportantfortheutilizationofwetlandresourcesandtheintegrateddevelopmentofsaline-alkalinesoiltostudychemicalcharacteristicsofwaterenvironmentinthisregion.1NATURALENVIRONMENTCHARACTERISTICSOFTHEWE…  相似文献   

黄河三角洲滨海湿地损失和退化的自然因素   总被引：4，自引：0，他引：4  

姚长新  袁红明  孟祥君  李绍全 《海洋地质与第四纪地质》2011,(1):43-50

黄河三角洲滨海湿地的损失和功能退化是对环境变化的响应,主要受自然因素控制.黄河入海水沙是形成滨海湿地的物质基础.自20世纪70年代以来黄河水沙减少,新生湿地的形成速率变小;波浪、潮汐、风暴潮、地面下沉和海平面上升等因素导致了滨海湿地的损失,湿地的面积呈减小趋势.由于淡水资源的短缺导致滨海湿地土壤严重的盐碱化和干旱灾害,...  相似文献   

Investigations of subsurface flow constructed wetlands and associated geomaterial resources in the Akumal and Reforma regions,Quintana Roo,Mexico     

Mark P. S. Krekeler  Pete Probst  Misha Samsonov  Cynthia M. Tselepis  William Bates  Lance E. Kearns  J. Barry Maynard 《Environmental Geology》2007,53(4):709-726

Subsurface flow constructed wetlands in the village of Akumal, Quintana Roo, Mexico were surveyed to determine the general status of the wetland systems and provide baseline information for long term monitoring and further study. Twenty subsurface flow wetlands were surveyed and common problems observed in the systems were overloading, poor plant cover, odor, and no secondary containment. Bulk mineral composition of aggregate from two subsurface flow constructed wetlands was determined to consist solely of calcite using bulk powder X-ray diffraction. Some soil structure is developed in the aggregate and aggregate levels in wetlands drop at an estimated rate between 3 and 10 cm/year for overloaded wetlands owing to dissolution. Mineral composition from fresh aggregate samples commonly is a mixture of calcite and aragonite. Trace amounts of Pb, Zn, Co, and Cr were observed in fresh aggregate. Coefficients of permeability (k) varied from 0.006 to 0.027 cm/s with an average values being 0.016 cm/s. Grain size analysis of fresh aggregate samples indicates there are unimodal and multimodal size distributions in the samples with modes in the coarse and fine sand being common. Investigations of other geologic media from the Reforma region indicate that a dolomite with minor amounts of Fe-oxide and palygorskite is abundant and may be a better aggregate source that the current materials used. A Ca-montmorillonite bed was identified in the Reforma region as well and this unit is suitable to serve as a clay liner to prevent leaks for new and existing wetland systems. These newly discovered geologic resources should aid in the improvement of subsurface flow constructed wetlands in the region. Although problems do exist in these wetlands with respect to design, these systems represent a successful implementation of constructed wetlands at a community level in developing regions.  相似文献   

城市湿地管理与恢复   总被引：4，自引：0，他引：4  

于敬磊  鞠美庭  邵超峰 《湿地科学与管理》2007,3(1):36-39

城市湿地是城市重要的生态基础,具有许多生态功能和社会服务功能,合理开发和利用湿地资源是促进城市可持续发展的重要因素。结合国内外有关城市湿地的研究,指出城市湿地的3R管理策略:即鼓励居民积极休闲娱乐、湿地恢复、湿地科学研究。介绍了城市湿地恢复与重建的基础理论以及城市湿地恢复成效评估、评估标准的建立过程。  相似文献   

基于SPOT5遥感影像的湿地资源调查方法研究     

谭继强  孙丽梅 《测绘与空间地理信息》2007,30(1):19-23

通过利用SPOT5遥感影像对湿地资源调查方法的实验研究,探讨了遥感影像的融合方法,选取适合湿地资源调查的数据融合和重采样方法,并解译融合后的遥感数据。从而获取湿地研究区的分类数据。  相似文献   

湿地保护与建设     

李常建  唐琳虹 《海洋技术学报》2005,24(4):60-62,127

湿地不仅有着不可替代的巨大的生态功能,而且湿地更是重要的生命支持体系,为人类的生存和实现社会可持续发展提供了必要的生态环境。文章简单介绍了湿地的特点、现状、功能和社会效益。展望并分析了我国利用城市再生水建设人工湿地的发展前景以及我国建设湿地的优势。  相似文献   

Geomorphic controls of perched groundwater interaction with natural ridge-top depressional wetlands     

Jonathan M. Malzone  Ethan G. Sweet  Addison C. Bell  Gilbert L. Minzenberger 《水文研究》2020,34(4):1089-1100

Geographically isolated wetlands (GIWs) are commonly reported as having hardpan or low hydraulic conductivity units underneath that produce perched groundwater, which can sustain surface water levels independently of regional aquifer fluctuations. Despite the potential of GIW-perched aquifer systems to provide important hydrological and ecological functions such as groundwater storage and native amphibian habitat, little research has studied the hydrologic controls and dynamics of these systems. We compared several ridge-top depressional GIW-perched groundwater systems to investigate the role of watershed morphology on hydroregime and groundwater-surface water interaction. Ridge-top depressional wetlands in the Daniel Boone National Forest, Kentucky were chosen because they offer natural controls such as lack of apparent connection to surface water bodies, similar climate, and similar soils. Three wetlands with different topographic slopes and hillslope structures were mapped to distinguish key geomorphic parameters and monitored to characterize groundwater-surface water interaction. Wetlands with soil hummocks and low upland slopes transitioned from infiltration to groundwater discharge conditions in the spring and during storm events. The magnitude and duration of this transition fell along a continuum, where higher topographic slopes and steeper uplands produced comparably smaller and shorter head reversals. This demonstrates that ridge-top GIW-perched groundwater systems are largely sensitive to the runoff-recharge relationship in the upland area which can produce significant groundwater storage on a small-scale.  相似文献   

Eddy covariance‐based evapotranspiration for a subtropical wetland          下载免费PDF全文

Chin‐Lung Wu  Sanjay Shukla 《水文研究》2014,28(24):5879-5896

The eddy covariance (EC) method was used in a 30‐month study to quantify evapotranspiration (ET) and vegetation coefficient (K_CW) for a wetland on a ranch in subtropical south Florida. To evaluate the errors in ET estimates, the EC‐based ET (ET_C‐EC) and the Food and Agricultural Organization (FAO) Penman–Monteith (PM) based ET (ET_C‐PM) estimates (with literature crop coefficient, K_C) were compared with each other. The ET_C‐EC and FAO‐PM reference ET were used to develop K_CW. Regression models were developed to estimate K_CW using climatic and hydrologic variables. Annual and daily ET_C‐EC values were 1152 and 3.27 mm, respectively. The FAO‐PM model underestimated ET by 25% with ET_C‐EC being statistically higher than ET_C‐PM. The K_CW varied from 0.79 (December) to 1.06 (November). The mean K_CW for the dry (November–April) season (0.95) was much higher than values reported for wetlands in literature; whereas for the wet (May–October) season, K_CW (0.97) was closer to literature values. Higher than expected K_CW values during the dry season were due to higher temperature, lower humidity and perennial wetland vegetation. Regression analyses showed that factors affecting the K_CW were different during the dry (soil moisture, temperature and relative humidity) and wet (net radiation, inundation and wind speed) seasons. Separate regression models for the dry and wet seasons were developed. Evapotranspiration and K_CW from this study, one of the first for the agricultural wetlands in subtropical environment, will help improve the ET estimates for similar wetlands. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献