不同植物组合对中小河道水体及底泥重金属与营养盐净化评估

为探究乡村旅游业及其周边生活废水对水体及底泥中重金属和营养盐影响，以及不同植物能否缓解产生的污染，以黄龙岘村为研究对象，分析了当地6条河流水体及底泥中重金属和营养盐含量，利用健康风险评价和潜在生态风险指数法分别评估了当地水体和底泥对人体的潜在危害，采用冗余分析和相关性热图揭露水体中重金属和营养盐之间的内在关系，利用不同植物组合的河流探究污染缓解情况。结果显示，研究区内6条河流的上、中及下游总体符合国家地表水环境Ⅴ类标准(GB 3838—2002)。健康风险评价表明，除对照河流外，其它河流均处于可接受范围内，重金属暴露的致癌风险值为儿童大于成人，且饮水途径是引起风险的主要原因。沉积物中重金属潜在生态风险值依次为上游、中游和下游。沉积物中Cd的单项污染物风险值最高，且Cu可能会与水体中营养盐协同作用，进而诱导水质环境恶化。应加强对水体中Cd和Cu的治理及修复，并及时排查周边可能造成高重金属污染的源头。水杉、构树和小蜡可优先作为研究区河流中生态修复重金属的先行植物。     

锤击组件的结构采样器在含重金属底泥采取率中的实践应用

底泥采样是指为了研究排入水体的重金属污染物在底泥中积累、分布、转化和迁移的规律,需要采集的底泥样品,目前市场上的底泥采样器主要包括活塞式柱状取样器、重力式柱状采集器和抓斗式采泥器。对虞河重金属底泥分布、污染厚度、污染因子及浓度等基本特征进行底泥采样,为后期污染现状勘查及疏浚工程提供工程依据。     

河流重金属污染底泥的修复技术研究进展

基于我国部分河流底泥的重金属污染现状,综述了国内外关于底泥重金属处理研究进展和成果,并详细阐述了重金属去除的生物修复法.同时,结合重金属污染因子去除效率、处理成本以及环境安全性等问题,笔者提出生物修复法是一种具有潜在应用前景的方法,今后的深入研究可能为河流底泥重金属的处理和后续的资源化利用提供一定的理论依据.     

湘江流域长株潭段底泥重金属污染评价

在湘江长株潭段共采集了6个底泥样品,监测了Cu、Pb、Zn、Cd、Ni、Cr、As、Hg8种重金属元素,采用地积累指数法和潜在生态危害指数法对湘江长株潭段底泥重金属污染进行评价.结果表明:湘江长株潭段底泥受重金属污染较严重,各种重金属的污染程度由强至弱依次为Cd>Zn>Cu>Pb=Ni>Hg>As=Cr;金属污染物对湘江长株潭段构成的潜在生态危害由强至弱依次为Cd>Hg>Pd>Cu>Zn>As>Cr,其中Cd的影响占主导地位.对于评价效果,地积累指数法和潜在生态危害指数所反映的情况有所差异,原因主要是参比体系及参比值的差异.     

水质稳定剂在锰铁高炉煤气洗涤水中的应用

水质稳定剂在锰铁高炉煤气洗涤水中的应用新余钢铁有限责任公司潘真崔建平吴霞１问题提出锰铁高炉煤气洗涤水是我厂水量大、水质污染严重的污水之一，其中主要的污染物是氰化物和悬浮物。目前，我厂对该污水的处理着眼于降低悬浮物含量，通常采用平流沉淀池投加絮凝剂以降...     

赣江上游龙迳河水体氨氮与重金属污染分布特征及风险评价

论文以我国典型的稀土矿区流域——赣江上游龙迳河为研究对象,自上游至下游采集了15个水样并现场测定了水体pH值,测试和分析了氨氮、硝氮、亚硝氮和Cr、Cd、Zn、Cu、As、Hg、Pb、Mn 8种重金属含量和相关性,并采用内梅罗综合污染指数评价法对重金属污染程度进行评价.结果表明:①龙迳河流域主要的重金属污染物为Mn、Hg、Pb,其超出地表Ⅱ类水质标准分别为93%、20%、6.7%;②表层水体中亚硝氮、硝氮、氨氮和重金属Zn、Mn、As、Cd、Pb沿程变化具有相似性,且重金属Zn、Mn、As、Cd、Pb与氨氮具有显著的正相关性,表明重金属Zn、Mn、As、Cd、Pb之间可能具有一定的同源性且氨氮含量与该重金属在水中的分布有密切联系;③龙迳河水质优良、良好、较好、较差和极差占整体采样点的概率分别为6.67%、26.67%、33.33%、6.67%和26.67%,河流水质整体较差,部分采样点水质较好,重金属污染上游大于下游.      

某铅锌冶炼厂污水处理站升级改造探讨与实践

某铅锌冶炼厂现有污水处理系统采用两段中和、重金属沉降工艺,水质满足《铅、锌工业污染物排放标准》(GB25466-2010)。为进一步降低废水中重金属污染物浓度,提升污水站出水水质,满足企业废水回用要求,对现有处理设施进行升级改造。文章介绍了升级改造的思路与措施,引入电化学处理工艺,实践证明:升级改造后污水处理站出水水质重金属污染物浓度能稳定达到《地表水环境质量标准》(GB3838-2002)Ⅲ类标准要求,达到企业回用水质要求,处理成本合理。     

萍水河水质空间分布特征及水质评价对比研究

流域水质直接关系到人体健康和生态安全。以萍水河向阳湖至何雁桥段为研究对象,分析其水质空间特征,综合4种方法进行水质评价,进一步利用多元统计和级别差方法对比分析水质评价结果。结果表明：1)COD、NH₃-N、TP和TN的最高浓度位于赤山桥处;上游(向阳湖-桥头村)和下游(赤山桥-何雁桥)总体水质较好,部分采样点TN、Fe和Mn轻度超标,污染程度明显弱于中游(桥头村-赤山桥)。2)最差水质级别均为Ⅴ类或劣Ⅴ类水,污染程度属严重污染及以上;单因子评价法确定总氮(TN)为首要污染指标;主成分分析法确定2个主成分,可解释为营养盐污染指标和地质沉积环境指标。3)4种方法两两之间呈显著正相关,相关系数为0.937～0.994,但水质级别表现出明显的差异性;级差法结果表明,3种综合水质评价方法的水质级别顺序为：内梅罗污染指数法<综合污染指数法<主成分分析法。研究成果可为流域水质评价工作和研究提供参考,同时为流域水资源开发利用和水环境保护及综合治理提供科学依据。     

双桥河流域农田土壤重金属分析与评价

金矿石的开采及选冶生产会将矿石中的重金属释放到环境中,对环境造成污染。为了研究金矿石开采及选冶生产对土壤环境质量的影响,在研究区域采集不同地貌单元的土壤样品,分析测定其重金属含量;通过与国家土壤环境质量标准比较,以及与邻区土壤样品分析测定结果对照,结果表明,不同地貌单元农田土壤中汞污染最严重,超标倍数平均值为1.29,是各地貌单元的主要污染物;山前冲洪积斜塬区、河流冲洪积阶地区及黄土沟壑台塬区土壤重金属综合污染指数分别为1.98,1.53,1.59,达到轻度污染;土壤综合累积污染指数分别为23.57,18.66,19.56,达到极严重累计污染。研究结果说明,人类矿业活动对土壤环境质量的影响值得重视,土壤中重金属污染与矿业活动频繁息息相关。     

地质高背景区铅锌矿废弃地土壤重金属污染评价

调查研究了某废弃铅锌矿区周边农田土壤中重金属Hg、As、Cd、Cr、Pb、Cu、Zn的污染状况,并结合单因素指数法、地累积指数法、污染指数负荷法、灰色聚类法及聚类热图分析对重金属污染程度和空间分布状况进行评价,采用相关性分析和主成分分析识别污染途径。结果表明,研究区Cd、Zn、Hg、Pb、Cu和As含量均超过贵州省土壤背景值。Cd的外源污染最严重,Zn、Pb、Hg次之。重金属污染程度与河流以及距矿区距离呈正相关。主要污染因子为Cd,次要污染因子为Hg和Zn,各采样点均处于严重污染。研究区重金属来源可分为4类,Cu、Cd、Zn属工业源污染,主要为矿山开采;As、Hg污染与工业源和农业源有关;Cr、Pb含量受交通源与工业源以及自然源多方面影响。     

Sediment and Metals Modeling in Shallow River

It is a challenge to apply coupled hydrodynamic, sediment process, and contaminant fate and transport models to the studies of surface water systems. So far, there are few published modeling studies on sediment and metal transport in rivers that simulate storm events on an hourly basis and use comprehensive data sets for model input and model calibration. The United States Environmental Protection Agency (USEPA) in 1997 emphasized the need for credible modeling tools that can be used to quantitatively evaluate the impacts of point sources, nonpoint sources, and internal transport processes in 1D/2D/3D environments. A 1D and time-dependent hydrodynamic, sediment, and toxic model, within the framework of the 3D Environmental Fluid Dynamics Code (EFDC), has been developed and applied to Blackstone River, Mass. The Blackstone River Initiative (USEPA) in 1996, a multiyear and multimillion-dollar project, provided the most comprehensive surveys on water quality, sediment, and heavy metals in the river, and served as the primary data set for this study. The model simulates three storm events successfully. The river flow rates are well calculated both in amplitude and in phase. The sediment transport and resuspension processes are depicted satisfactorily. The concentrations of sediment and five metals (cadmium, chromium, copper, nickel, and lead) during the three storm events are also simulated very well. Numerical analyses are conducted to clarify the impacts of contaminant sources and sediment resuspension processes on the river. While point sources are important to sediment contamination in the river, other sources, including nonpoint sources from watershed and bed resuspension, were found to contribute significantly to the sediment and metals in the river. Point sources alone cannot account for the total metals in the river. The model presented in this paper can be a useful tool for studying sediment and metals transport in shallow rivers and for water resource management.     

有效态与TCLP法评价沉积物重金属生态环境风险

采集了河道沉积物样品,测定了沉积物中重金属的有效态,并采用TCLP法测定了Cd、Pb和Zn的含量,同时开展了生态环境风险评价。结果表明,根据农产品产地土壤重金属污染程度的分级标准,该河段沉积物中Cd超标率为60%,Zn的超标率为20%,Pb的含量都在安全值范围内。沉积物中三种重金属的均为低风险。TCLP提取沉积物中Cd、Pb和Zn含量,与国际标准值对比发现,沉积物中上下游的两个样品Cd含量大于国际标准值;所有沉积物样品中的Pb、Zn的含量均大于国际标准值。内梅罗综合污染指数结果表明,调查区域河段的沉积物为重度污染。根据有效态和TCLP提取的重金属含量评价结果表明,两种评价方法存在一些差异,但综合两种评价结果,该河流流域确实存在污染的风险。     

金矿区水系沉积物重金属含量影响分析

通过对比金矿区水库底泥剖面与邻区水系沉积物重金属含量,评价了底泥中砷、铬、汞、铅、铜、锌等重金属的污染现状;结合剖面不同层位物理性状,分析了影响重金属富集的两个因素:一是沉积物自身的吸附作用,二是区域矿业活动的强弱.     

南京生态科技岛海绵城市河道系统植物技术设施对水体重金属及营养盐净化能力评价

为探究海绵城市植物技术设施对重金属及营养盐净化能力,以江心洲南京生态科技岛河道系统为研究对象,对其上下游水体中重金属及营养盐含量进行分析,通过综合污染指数法对上下游重金属风险进行评估,采用冗余分析及Spearman相关系数探究水体环境因素对重金属含量的影响,利用河道区域四种植物技术设施(河岸缓冲带、植被过滤带、生态浮岛、台地式石笼护岸)探究不同植物组合对水体中污染物的净化能力。结果显示,江心洲河道上游重金属的枯水期、丰水期及平水期WQI值分别为1.85、1.74及2.90,分别对应为重金属轻度污染、轻度污染及中度污染。而河道下游重金属的枯水期、丰水期及平水期的WQI值分别为0.18、0.30及0.52,均未存在污染现象。河道上游水体中pH是影响重金属含量的最重要因素,pH与溶解氧(DO)、总氮(TN)、五日化学需氧量(COD₅)及总磷(TP)呈正相关。河道下游水体的pH也是影响水中重金属含量最重要的环境因素,其与溶解氧(DO)呈显著正相关。水体中营养盐净化能力大小为河岸缓冲带>植被过滤带>生态浮岛>台地式石笼护岸。相比其它植物组合,乔灌木群落栽植对水体中营养盐净化最具有潜力。     

Simulation of Metals Total Maximum Daily Loads and Remediation in a Mining-Impacted Stream

Simulation of metals transport was performed to help develop metals total maximum daily loads (TMDLs) and evaluate remediation alternatives in a mountain stream in Montana impacted by hundreds of abandoned hardrock metal mines. These types of watersheds are widespread in Montana and many other areas of the western United States. Impacts from abandoned hardrock or metal mines include loadings of sediment, metals, and other pollutants causing impairment of multiple beneficial uses and exceedances of water quality standards. The United States Environmental Protection Agency (EPA) Water Quality Analysis Simulation Program (WASP) was used to model and evaluate TMDLs for several heavy metals in Tenmile Creek, a mountain stream supplying drinking water to the City of Helena, Mont. The model was calibrated for baseflow conditions and validated using data collected by the EPA and the United States Geological Survey, and used to assess existing metals loadings and losses, including interactions between metals in water and bed sediment, uncertainty, water quality standard exceedances, TMDLs, potential source areas, and required reductions in loadings. During baseflow conditions, adits and point sources contribute significant metals loadings to Tenmile Creek. Exceedances of standards are widespread throughout the stream under both baseflow and higher flow conditions. Adsorption and precipitation onto bed sediments play a primary role in losses from the water column in some areas. Modeling results indicate that some uncertainty exists in the metal partition coefficients associated with sediment, significance of precipitation reactions, and in locations of unidentified sources and losses of metals. TMDLs and loading reductions were calculated based on variations in flow, concentrations, loadings, and standards (which vary with hardness) along the mainstem. In most cases, considerable reductions in loadings are required to achieve TMDLs and water quality standards. Reductions in loadings from point sources, mine waste near watercourses, and streambed sediment can help improve water quality, but alteration of the water supply scheme and increasing baseflow will also be needed.     

Water Quality and Ecosystem Modeling of Tidal Wetlands

A water quality and ecosystem model is developed to simulate nutrients, heavy metals, and aquatic plants in the Erh-Chung Flood Way wetland in Taiwan. A sediment system was incorporated into the model. The RMA2 and WASP/EUTRO5 models were adopted as the basic framework with modifications and enhancement of kinetics to incorporate ecosystem dynamics and sediment-water interactions. Hydrodynamic results from the RMA2 model were used to quantify mass transport for the EUTRO5 model. The major effort in this study was adding four water quality variables; macrophyte biomass, suspended solids, heavy metals in macrophytes, and heavy metals in the water column and sediment were incorporated into EUTRO5 to form the water quality and ecosystem model. Site-specific water quality data were collected to support the model calibration and verification analyses.     

Brown trout as biomonitor of heavy metal pollution: effect of age on the reliability of the assessment

Brown trout (Salmo trutta L.) is a native fish of the rivers of northern Spain. It is the dominant fish species in these rivers, and it is widespread over all the range of freshwater ecosystems in the area, including ecosystems potentially polluted with heavy metals. In this study, the potential of brown trout as biomonitor of heavy metal pollution and the effect of fish age on the reliability of the assessment are analyzed. Copper, lead, and cadmium concentrations of both abiotic compartments (water and sediments) and brown trout (S. trutta) from three northern Spanish rivers were analyzed. Significant correlations were found between sediment lead content and lead concentration in trout liver. One-year-old juvenile trouts were demonstrated to be useful as a biomonitor of copper and lead pollution, revealing between-location differences. Older trouts do not seem adequate to properly monitor heavy metal pollution. The effect of aging on the reliability of this species as biomonitor is discussed.     

Investigation of Cadmium Desorption from Different-Sized Sediments

Using the adsorptive reaction kinetics equation and the mass conservation equation, formulas for calculating the particulate heavy metal concentration (or the residual adsorption content of unit weight of sediment) and the dissolved heavy metal concentration were deduced. Furthermore, equations for calculating the equilibrium particulate heavy metal concentration (or the equilibrium residual adsorption content of unit weight of sediment) and the equilibrium dissolved heavy metal concentration were formulated. On the basis of these theoretically deduced formulas and through laboratory reactor modeling of artificially contaminated sediments with cadmium in suspension, heavy metal desorption rates from nonuniform sediment particles were studied. Both theoretical analysis and experimental results indicate that adsorption and desorption of heavy metal pollutants to and from sediment particles are partly reversible. It is also noticed from the experiments that the adsorption and desorption rates of heavy metals to and from sediments are dependent on the content of active adsorption components in the sediments. The greater the content of active adsorption components, the higher the adsorption rate of the sediments and the lower the desorption rate. The total amount of heavy metal desorbed from sediments is directly proportional to the concentration of suspended sediment particles.     

Storm Water Detention Ponds: Modeling Heavy Metal Removal by Plant Species and Sediments

Laboratory and field studies were conducted to elucidate heavy metal removal by three wetland grasses and sediments in storm water detention pond. The removal of heavy metals including Cd, Cu, Pb, and Zn was mediated by fluid-flow intensity in the reactors. The growth of plants and the removal rates of contaminants were plant species dependent. All three wetland grasses removed contaminants from the spiked nutrient solutions. A first-order kinetic model adequately represented the removal of contaminants by plants. The analyses of undisturbed sediment cores in detention pond revealed strong stratification of heavy metal concentrations at the sediment–water interface. A simple model that integrates heavy metal removal by aquatic plants and sediments in storm water detention ponds is proposed. The model provides an estimate of contaminant residence time which can be related to hydraulic residence time in storm water detention ponds.