河道底泥中重金属的EDTA淋洗研究

以城市河道底泥为研究对象,用EDTA淋洗进行底泥无害化处理研究。分别探讨了EDTA浓度、淋洗时间、液固比等因素对底泥淋洗效果的影响。目的是为了给底泥中重金属的淋洗实际应用提供技术参数。实验结果表明:淋洗条件如EDTA浓度、淋洗时间和液固比都对淋洗效果有显著影响。本实验中所用底泥0.1 mol/L的EDTA在液固比10∶1的条件下,淋洗效果最好,淋洗30 min就能去除掉70%~80%的Cu和Cd。研究中还比较了淋洗前后底泥中重金属形态分布的变化,详细探讨了底泥与重金属的结合方式对淋洗效果的影响。从形态分析可以得出,原底泥中重金属的分布形态可以用来预测淋洗效果。EDTA淋洗主要针对的是离子态和碳酸盐结合态的重金属,对结合力较强的铁锰氧化物、有机物结合态和残渣态重金属效果较差。因此,可预先进行重金属形态分析来确定底泥是否可用EDTA进行淋洗。     

生物活性剂淋洗对河道底泥重金属毒性和生态风险影响评价

以河道底泥为研究对象,采用Tessier五步连续提取法比较了淋洗前后底泥中重金属的形态分布变化,并采用生物活性评价法,浸出毒性法,地累积指数法和潜在生态风险指数法比较及评价了生物活性剂槐糖脂淋洗前后底泥重金属的生物活性、浸出毒性和生态风险系数的变化。研究同时还采用三维荧光对底泥中溶解性有机质进行了分析。结果表明:淋洗后底泥重金属形态分布发生变化,重金属的迁移能力降低,生物活性和危害性降低,浸出毒性减小,单一和综合潜在生态风险降低,说明淋洗是一种有效的降低底泥重金属环境危害的方法。经淋洗后的底泥中重金属稳定性提高,对生态风险小,可以进一步进行资源化利用。     

有机酸淋洗修复复合重金属污染河道底泥研究

针对高粘性Cu、Zn复合重金属污染河道底泥,采用酒石酸、草酸、柠檬酸三种有机酸作为淋洗剂对污染土进行淋洗修复,通过振荡淋洗方法,探究淋洗剂浓度、淋洗时间对重金属去除率的影响规律,采用BCR三步提取法对淋洗前后土壤重金属形态进行分析.研究结果表明:3种有机酸对Zn的去除率优于对Cu的去除率,得到最佳淋洗方案为浓度0.4 ...     

盐城市县域河道底泥重金属生态风险分析

为改善盐城市河流水环境,维护河流健康,针对盐城市9条代表性县域（地区）河流开展了底泥重金属监测和生态风险评估。结果表明：9条河流底泥重金属Cu、Zn和Pb均存在不同程度的富集累积,Pb富集程度相对最大,各河流Pb均表现为偏中度-中度污染,在部分河流的生态危害等级为中等;Zn和Cu富集程度相对较小,污染程度相对较轻,形成的生态危害等级为轻微。总体上,Cu、Zn和Pb所形成的生态综合危害风险在9条县域河流中均较为轻微。     

青浦区白鹤镇村级河道底泥重金属污染调查与分析

为分析青浦区白鹤镇村级河道底泥污染特征及对环境的危害程度,本文选取镇内36条村级河道对底泥进行定点采样和研究分析,并利用潜在生态风险指数法、Pearson相关性和R型聚类分析法对底泥重金属进行污染风险评价和来源探讨。结果表明,各种重金属潜在生态风险指数(E_i^r)均值大小依次为Hg>Cr>As>Cu>Ni>Pb>Cd>Zn;Pearson相关性和R型聚类分析表明,底泥中重金属Cu、Cd、Zn、Cr、Hg主要与农药或化肥使用有关,Pb和As主要与道路交通污染有关,Ni主要与工业生产有关。通过分析河道底泥污染特征,可为底泥妥善处置及河道精准治理提供数据支撑。     

水泥潜入河道底泥对重金属锌阻截作用的研究

基于水泥随入渗污水潜入河床淤泥模拟试验,分析了水泥潜入对污水中重金属锌的阻截作用,揭示了污水所含重金属锌沿深度方向的变化特性。结果表明:水泥潜入河道淤泥可以有效阻截重金属锌在土壤中的纵向迁移;在一定范围内,土壤阻截重金属锌的作用随着水泥潜入量的增大而增大;在水泥潜入的条件下,重金属锌的表聚作用明显,即土壤阻截重金属锌的作用随深度的增大而减小。     

流域综合治理工程中河道底泥清淤深度的确定

以海盐县武原街道城东片区内的海盐县古荡河流域（城东片区）三期综合治理工程为例,通过底泥采样,对河道清淤底泥进行了取样及相关试验,并对底泥重金属总量垂直分布以及生物可利用重金属垂直分布等展开分析,最后应用临界累积深度测算公式进行了该河道环保清淤深度的确定。结果表明,在外界条件适宜的情况下,该河道氧化层、污染层、过渡层内重金属含量高且释放的可能性较大,应作为河道底泥清淤的重点层位。     

重金属污染河道疏浚底泥稳定化实验研究

以底泥浸出毒性为指标,采用了直观分析、方差分析和单因素分析,探索了生石灰、磷酸二氢钾和天然斜发沸石协同作用对重金属稳定化效果。结果表明:生石灰、磷酸二氢钾稳定重金属效果显著,沸石效果较差;最优配比为底泥∶生石灰∶磷酸二氢钾∶天然斜发沸石为100∶6∶6∶0,底泥中Mn、Cd、Pb、Cu、Zn浸出浓度分别降低了96.6%、95.9%、98.7%、99.5%、94.7%;固化剂达到最优配比时,重金属浸出毒性满足填埋场污染物控制标准和上海市污水综合排放标准,为填埋处理和资源化提供了依据。     

共基质生物刺激技术去除城市河道底泥难降解有机污染物研究

随着城市河道外源污染的有效控制,河道污染底泥的治理在全面解决水体污染中的地位日渐突出。受污染底泥中的难降解有机物长期残留在环境中,对生物和人类健康造成风险。研究采用共基质生物刺激方法,在深圳河污染底泥中单独投加乙酸钠和甲醇,通过试验,利用微生物的共代谢行为,考察有机物去除效果。研究结果表明:(1)深圳河底泥中投加共基质乙酸钠和甲醇后,刺激底泥微生物增殖,进而促进底泥生物降解;(2)使用共基质生物刺激技术可有效去除有机污染物,但对底泥还原状态和黑臭问题并无改善,这可通过后续向底泥投加化学氧化剂加以解决。     

多泥沙水质水轮机设计与抗磨蚀处理

在多泥沙水质水轮机设计中,采用多种设计新方法和选型理念,目的是为了在保证水轮机性能的基础上,较好解决过流部件磨蚀问题.蜗壳、转轮、导叶的设计和选材都采用抗磨蚀处理.通过西藏隆子水电站的实践,取得了较好的效果.表1个.     

Fractionation of heavy metals in sediment cores from the Ell-Ren River,Taiwan

Fractionation of heavy metals (Cr, Cu, Co, Zn, Ni, and Pb) in sediment cores taken from three heavily polluted locations of the Ell-Ren River in southern Taiwan was studied. After the three sediment cores were separated into several depth sections, sequential extraction procedure was used to determine the variations in heavy metal binding fractions (exchangeable, bound to carbonates, bound to Mn oxides, bound to Fe oxides, and bound to organic matter) with different sediment depth, and followed by multivariate analyses. It turns out that a deeper sediment depth tended to result in smaller amounts of total extractable heavy metals (TEHMs), indicating that heavy metal pollution of the river has been intensifying these years. The decreasing order of TEHMs was: Zn > Cu > Pb > Cr > Ni > Co. The TEHMs Zn and Cu detected from different depth of the three sediment cores were mainly originated from “bound to carbonates” and “bound to organic matter” fractions, respectively. Also, the percentages of the heavy metals contained in each of the five binding fractons only slightly varied with sediment depth. From multivariate analyses, all the heavy metals except Co behaved similarly and might be discharged from the same pollution sources.     

Immobilization of heavy metals in sediment dredged from a seaport by iron bearing materials

Pot and field trials were carried out using sediment dredged from the port of Bremen (Germany) and deposited in a settling basin near Bremen; the sediment is polluted with Cd and Zn. Five iron-bearing materials were added to the soil (1% pure Fe in soil dry matter) to immobilize the heavy metals: ‘Red mud’ from the aluminium industry, sludge from drinking-water treatment, bog iron ore, unused steel shot and steel shot waste. The pH and CEC were little influenced by any of these treatments, but the NH₄N0₃ and DTPA extractable amounts of Cd and Zn, and particularly the uptake of Cd and Zn by plants, were markedly reduced. It was demonstrated that red mud and precipitated Fe-bearing sludge were the most effective materials. They caused an increase in the adsorption capacity of the dredged sediment with respect to Cd of about 50%. In the pot trials, NH₄N0₃ soluble amounts of Cd and Zn in samples of soil treated with these materials were reduced by 50% (DTPA: −20%), while the uptake by plants was reduced by 20–50%. In the field trial, Cd and Zn were immobilized in the soil to a certain extent, but less effect was observed on the concentrations in plants and soil extracts compared with the pot trials. In practice, red mud is unsuitable as it contains large amounts of Cr and Al³⁺ ions. Therefore, only sludge from drinking-water treatment, as long as the As concentration in it is low, remains as a useful material for immobilizing heavy metals in polluted sediment dredged from a seaport.     

图们江年输沙量的估算及下游河道冲淤治理措施

1 概况图们江位于吉林省东南部,是一条中、朝、俄三国的界河,其流域地形地貌类型复杂多变,山地多,平原少,山地面积占流域面积的61．3%,山高坡陡,水流速度快,易产生冲刷,     

泥沙粒径对重金属污染物吸附影响的研究

本文系统研究了不同粒径泥沙颗粒对重金属污染物的吸附作用，粗细不同的泥沙对重金属污染物的吸附能力差异很大，因此研究天然河流泥沙吸附能力必须考虑泥沙组成的非均匀性和各级泥少的含量，度量泥少量粒吸附能力的标准主要是吸附活性组分的含量，而不仅是粒径大小。     

River, reservoir and lake sediment contamination by heavy metals downstream from urban areas of Switzerland

This paper quantifies sediment contamination by heavy metals in four reservoirs and one lake located downstream from major urban areas in Switzerland. The waterbodies include the Wettingen Reservoir (located on the Limmat River downstream from Zürich), the Klingnau Reservoir (on the lower Aare River), the Wohlen Reservoir (downstream from Berne), the Verbois Reservoir (downstream from Geneva) and Vidy Bay (Lake Geneva, city of Lausanne). For all sediment cores and contaminants, a trend is observed from high contaminant values in the lower part of the cores, decreasing to lower concentrations in the upper part of the cores. However, for each site and each element, specific features are recognized. Applying the criteria of the Swiss ordinance on soil protection, all sediment cores must be classified as contaminated by one or more contaminants and at variable levels. From these data, it is concluded that: reservoirs and lakes located downstream from major urban centres in Switzerland have accumulated significant volumes of contaminated sediments in the past, representing the largest, but not the most intensely, contaminated sites on a national scale; the main environmental risk is remobilization of the contaminants and their return to the food chain, particularly by infiltration into the groundwater; and although the processes of remobilization are identified, the conditions of occurrence and the amplitude of the processes are still poorly known. Different options of reservoir and lake sediment management also are discussed and further research topics defined.     

东湖沉积物中重金属垂向分布特征及污染评价

为了掌握武汉东湖的水环境状况,以沉积物为研究对象,使用电感耦合等离子体质谱仪(ICP-MS)测定了不同湖域沉积物柱状样中9种重金属(Cd、Zn、As、Cu、Co、Pb、Mn、Cr、Ni)含量,对重金属元素的垂向分布特征进行了研究,并采用地累积指数法对重金属的污染程度进行评价。结果表明:沉积物中9种重金属元素含量排序为MnCrPbZnNiCuCoAsCd;垂向分布特征为Cr、Ni的含量随沉积物深度增加而增加,Cu、As、Cd的含量随沉积物深度增加而减少。地累积指数评价表明,郭郑湖西岸污染最为严重,汤菱湖最轻,累积较为严重的是Cr、Mn、Cd和Pb,其中Cd和Pb达到中度污染程度。