京津冀地区主要水系沉积物中重金属污染状况研究

简要综述了京津冀地区主要水系及其流域底泥沉积物的理化特性,系统讨论了该地区底泥沉积物中重金属(Cu、Pb、Zn、Cd、Cr)的分布特征,利用相关性分析分析了河流理化特性与重金属浓度间的关系,采用潜在生态危害指数法评价了此地区水体沉积物中重金属的潜在生态风险。结果表明,研究区域的河流理化特性与其背景值基本一致;重金属浓度评价结果为：Zn>Cr>Cu>Pb>Cd; pH与总氮、总磷与有机质存在一定的相关性,元素Pb与Cd,元素Zn与Cr间存在强相关性;元素Cd的潜在生态危害等级涵盖低、中等、重、严重四个等级,其余大部分样点处于对生态环境危害程度较低的等级。     

基于PMF模型的龙子湖表层沉积物重金属源解析

为了准确地鉴别龙子湖表层沉积物中重金属来源，从野外采集了21个沉积物样品，测定了沉积物中Cd、Cu、Mn、Ni、Pb和Zn的含量，并用PMF模型进行了来源识别。研究结果显示，表层沉积物中六种重金属的平均含量分别为1.31,29.20,436.8,30.93,27.58,151.7 mg/kg。除Mn外，其它五种重金属的平均含量均超安徽省土壤背景值，其中Cd超背景值程度最高。PMF解析结果显示，龙子湖表层沉积物重金属主要受工农业活动、交通及土壤母质造成的自然来源的共同影响。其中，Mn在沉积物中的积累以自然源为主，Cd、Zn的来源以工农业排放为主，Pb、Cu的积累则主要源自交通污染，Ni具有自然和人为的共同来源。     

煤矸石堆存区周边土壤重金属污染特征及风险评价

为探究长期堆存煤矸石中重金属在周边盛行风向土壤里的分布特征及潜在风险,以宁夏枣泉煤矿煤矸石堆存区周边土壤为研究对象,对煤矸石堆存区周边盛行风向土壤中5种重金属(Cu、Zn、Pb、Cr、Mn)总量及重金属赋存形态特征进行深入分析,开展了土壤重金属生物活性分析及评价。结果表明:由于煤矸石的长期堆放、风力、雨水淋溶等,堆存区边缘处重金属(Zn、Pb和Mn)含量较高,且随着距离的增大呈下降趋势;相关性分析中土壤pH值与Zn、Pb含量呈极显著负相关性,与Mn含量呈显著负相关性,与Pb和Cr的可交换态呈显著负相关性,总氮(TN)与Cu的有机质结合态呈极显著负相关性,与残渣态呈极显著正相关性;RAC评价结果表明Pb在土壤中具有较高风险水平,其余重金属潜在风险水平较低。     

鄱阳湖表层沉积物重金属污染特征及风险评价

分析了鄱阳湖17处表层沉积物中重金属Cu、Zn、Pb、Cd、Cr、Ni、As、Hg、Co的含量,运用潜在生态风险评价法探讨表层沉积物重金属潜在生态风险。17处沉积物中Cu、Zn、Pb、Cr、Ni、Co、Mn、As、Cd均值的生态风险水平为低,沉积物中Hg的潜在生态风险水平为中等,湖泊沉积物重金属的潜在生态风险贡献率大小依次为HgCuCdPbAsCoNiCrZn,鄱阳湖沉积物的重金属综合生态风险水平属于中级。     

扬州古运河三湾段沉积物中重金属潜在生态风险评价及形态变化特征

扬州古运河是京杭大运河最古老的一段,为了解沉积物中重金属污染状况,采用Hakanson潜在生态风险评价扬州古运河三湾段沉积物中重金属Cr、Ni、Cu、Zn、Cd和Pb的风险水平,并对形态分布特征进行了研究。结果表明:扬州古运河六种重金属的含量均高于背景值,其中Cd含量为其背景值的13.15倍。沉积物中重金属的累积潜在生态风险指数RI高达456.55,沉积物的总体潜在生态风险等级为强。沉积物中Pb的主要赋存形态主要以铁锰氧化态存在,而Zn和Cd主要以酸可溶态形式存在,说明这三种重金属的潜在生态风险水平较高。     

吕梁市降雪中重金属污染分析

通过对吕梁市2017年12月至2018年1月两场降雪样品的采集,用电感耦合等离子体原子发射光谱法测定了样品中Cu、Pb、Zn、Cd、Cr、Mn等6种重金属的含量,研究了吕梁市降雪中重金属的含量特征,利用富集系数法分析了其来源,并对其潜在生态风险进行了评价。结果表明:降雪中重金属含量顺序为Zn Mn Pb Cu Cr Cd,融雪可排入自然水体。富集系数分析表明,降雪中Cr的来源主要来自地壳,Mn受到人为活动的影响,属于中度富集,Cu、Zn、Cd、Pb属于严重富集。潜在生态风险评价显示,降雪中重金属的潜在生态风险为中等生态风险水平,其中Cd的生态危害指数最高。     

石灰调质污泥重金属形态分布及资源化分析

针对南方某生物滤池(BAF)工艺污水处理厂,分析了初沉污泥、生物污泥、石灰调质污泥中Pb、Zn、Cu、Cd、Ni、Cr六种重金属含量及形态分布。结果表明:三种污泥中生物污泥的重金属含量较低,可作为污泥农用和污泥制砖资源化;石灰调质过程使污泥中Zn、Cu、Pb的总量升高,Cr总量降低,Cd和Ni的总量变化不大;石灰调质过程有利于污泥中的Zn、Cu和Cr从不稳定态向稳定态转化。     

合肥市南淝河表层沉积物重金属污染评价

对合肥市南淝河表层沉积物中重金属污染状况进行采样调查,选取了8个采样点,测定了沉积物中Cr、Cd、Pb、Ni、Zn、Cu 6种重金属的含量,并采用地质累积指数法和Hakanson潜在生态风险指数法对其污染程度进行分析评价。地质累积指数评价结果表明:南淝河6种重金属的生态风险等级由强至弱依次为Cd、Zn、Cu、Ni、Pb、Cr;生态风险指数评价结果显示:在南淝河沉积物重金属中,Cd存在一定的潜在生态风险,Cr、Pb、Ni、Zn、Cu均处于轻微等级,重金属生态风险等级由强至弱依次为Cd、Cu、Ni、Pb、Zn、Cr,多数采样点的沉积物重金属综合潜在生态风险等级处于轻微级,个别采样点达到了中等甚至强生态风险等级。     

冶炼厂周围土壤中Cu、Pb、Zn、Cd的形态分布研究

目的：观察冶炼厂周围土壤的重金属分布情况。方法：本研究选取云南鸡街周围荒地土壤为样品,采用消解法对土壤中的Cu、Pb、Zn、Cd进行总量分析,并运用Tessier连续提取的五态方法研究该区土壤中Cu、Pb、Zn、Cd的形态分布特征,来检测该地区的土壤生态。结果：该冶炼厂周围土壤中四种重金属的总浓度高于国家土壤环境质量指标;形态分析发现Cu、Pb、Zn、Cd的主要形态为残渣态,可交换态所占比例最小;四种重金属的生物活性和迁移能力大小均为Cd〉Pb〉Zn〉Cu。结论：（1）该地区土壤被重金属污染。（2）为该地区土壤修复提供理论依据,重金属的提取和回收提供资料。     

南四湖沉积物重金属含量水平与生态风险

本论文研究了南四湖沉积物中重金属的含量及生态风险;结果表明沉积物重金属Cd、Cr、Cu、Pb、Zn、Ni、Co的含量为0.08~1.12、58.92~135.62、38.09~78.65、24.51~53.95、110.51~235.36、11.30~65.40、4.12~20.14 mg/kg,均值顺序Zn Cr Cu Pb Ni Co Cd;重金属生态风险评价结果表明,Cd和Zn的相对富集因子明显高于其它元素,且某些点这两种元素的富集程度较高。因此,在南四湖环境污染防控中,应该关注沉积物中的Cd、Zn的污染。     

Soil effects due to sewage sludge application in agriculture

Field trials show that increased nutrients (mainly P) and heavy metals in soil due to agricultural use of sewage sludge have mainly to be expected when sludge is applied in too high amounts. The biological effects of heavy metals on plants are determined by their solubility which is increased by pH decrease and degradation of organic matter. Normally, it should be expected that the microbial activity in soil would increase with the application of organic matter in sewage sludge. But, also negative effects on the microflora by simultaneous enrichment of organic matter or inorganic and organic pollutants were found. The most important deleterious effects on soil microorganisms are the reduction in size of the total biomass, a reduced nitrogen fixing activity and changes in the composition of microbial populations of the soil. At what stage heavy metal toxicity to soil microorganisms or to microbial processes in soil is likely to become evident is unfortunately still uncertain. Again, the soluble fraction of heavy metals (also of organic pollutants) is a determing factor. To minimize the shown environmental risks an adequate sludge management is proposed.     

Removal of Heavy Metal Impurities from Dredged River Sediment

This article shows the results of a study that aims to remove the sediment fraction containing heavy metals from river sediment by flotation. Different parameters such as pH, flotation time, different collectors, distilled water, tap water, and different salts were investigated to achieve a high separation efficiency. Explanations are suggested for the obtained results. Results of flotation revealed that 63 % by weight of the input dredged sediment can be safely and successfully separated, thus, meeting the standard environmental requirement of current Flemish (Belgium) regulation “bodemsaneringsdecreet” (February 1995). This dredged fraction could not be achieved before a flotation time of 15 min. Increasing flotation time would impart less metal content but with a lower yield. In the case of applying the settling technique, 55 % by weight of the dredged sample meeting the same standard specification was obtained. Results are explained in the light of a model, which assumes that sediment contains organic matter together with heavy metals, clay, and sand. Upon aeration, air bubbles are adsorbed on hydrophobic particles, which carry them up to the froth layer with the hydrophilic particles left behind in the pulp. The use of an organic collector has a minor effect on flotation process. Results of the settling technique are discussed.     

土壤酸碱度对重金属在土壤中行为的影响

分别对土壤酸碱度的定义、影响土壤酸碱度的因素、土壤酸碱度的变化对重金属的影响这几个方面做了综述,发现控制重金属元素地球化学行为的重要因素是土壤pH值。土壤中有机质含量的高低,可以控制土壤中重金属的地球化学行为。     

Acidification of Harbor Sediment and Removal of Heavy Metals Induced by Water Splitting in Electrodialytic Remediation

Abstract

Harbor sediments are often contaminated with heavy metals, which can be removed by electrodialytic remediation. Water splitting at the anion exchange membrane in contact with the contaminated material in electrodialytic remediation is highly important for the removal of heavy metals. Here it was investigated how acidification caused by water splitting at the anion exchange membrane during electrodialytic remediation of contaminated harbor sediment and hence the metal removal, was influenced by different experimental conditions. Two different experimental cells were tested, where the number of compartments and ion exchange membranes differed. Totally, 14 electrodialytic experiments were made, with varying remediation time, current densities, and liquid to solid ratio (L/S). pH in the sediment decreased slightly after 1 day of remediation, even if the sediment had a high buffering capacity, suggesting that water splitting at the anion exchange membrane started early in the remediation process. An increase in the voltage over the cell and a decrease in the electrical conductivity in the sediment suspension also indicated that the water splitting started within 1 day of remediation. When the sediment was acidified, the voltage decreased and electrical conductivity increased. After 5 days of remediation the sediment was acidified at the chosen current density (1 mA/cm²) and the main metal removal was observed shortly after. Thus it was crucial for the metal removal that the sediment was fully acidified. Lower metal removal was seen in an experimental cell with three compartments compared to five compartments, due to increased sensitivity of pH changes in the cell.     

Heavy metal removal within pilot-scale constructed wetlands receiving river water contaminated by confined swine operations

Three parallel pilot-scale surface flow constructed wetlands were employed to investigate heavy metal removal receiving river water contaminated by swine confined-housing operations in Taiwan. Wastewater from swine operation contained elevated levels of copper and zinc due to their abundance in feed. Two macrophytes, namely cattail (Typha latifolia) and reed (Phragmites australis), were planted to observe their heavy metal removal efficiency. Significant total recoverable copper and zinc reduction for three tested wetlands were 80 and 91% for unplanted control, 83 and 92% for cattail, and 83 and 92% for reed wetland systems. Acid-soluble forms were 56 and 86% of total recoverable influent metals for copper and zinc, respectively. More bioavailable zinc was subjected to releasing back to aqueous environment. Heavy metals entering the studied systems as insoluble forms were settling from water column. Concentrations of metals were higher in the vegetated sediments than in the non-vegetated sediments. The sequential extraction results of sediments indicated that most retained metals were in less mobile fractions. Most of metal uptake by vegetation remained in root portions. Translocations of both copper and zinc for tested macrophytes were not prominent. The metal species in incoming water and metal fractionations in sediment were demonstrated as the major factors to influence plant metal levels. The performance of the studied wetland systems can comply with local water criteria rendering for further water reuse.     

采煤塌陷湿地底泥对磷的吸附特征研究

采煤塌陷湿地沉积物-水界面磷的环境化学行为与其它类型湿地存在较大差异,且鲜有报导。对淮南矿区潘北煤矿2处塌陷湿地水体沉积物进行磷吸附动力学以及吸附等温实验研究,拟合实验结果得出：实验地区水体沉积物的磷吸附在较短的时间内即可完成,沉积物对磷的吸附能力较强,其饱和磷吸附容量最高达609mg／kg,饱和磷吸附容量以及吸附反应的自发程度与沉积物中的有机质含量具有一定的正相关关系,微生物在沉积物的磷吸附中具有一定的促进作用。     

乐安江流域重金属的来源与分布探析

为研究乐安江流域重金属的污染状况,于2008年12月在流域采集了水样和底泥,并在实验室用离心机离心底泥得到间隙水,用原予吸收方法测定底泥中重金属（Cu,Pb,Zn,Cd）的浓度含量和水体中重金属（Cu,Pb）的含量。结果表明,乐安江水体中重金属含量没有超过地表水环境质量标准Ⅲ,而底泥中重金属含量平均值与国家土壤环境质量标准Ⅲ相比,只有Cd未能达到标准。在浓度含量上,低泥中最高,间隙水中次之,水体中最少。     

“长株潭”地区湘江底泥重金属含量调查研究

通过调查分析湘江＂长株潭＂段表层底泥的锌、铜、镉、铬、铅、汞、锰等重金属含量,将底泥样品中重金属的含量分别与土壤环境质量标准、污水排入城市下水道水质标准、以及生活饮用水卫生标准中重金属含量进行比较,从而发现重金属在湘江＂长株潭＂段的污染严重程度。根据调查结果分析,对湘江＂长株潭＂段底泥重金属污染问题提出减排含重金属废水,有关部门应关注底泥重金属含量变化,和修复河床表层重金属含量高的底泥等建议。     

垃圾焚烧底渣中重金属的研究

采用Tessier四步分级提取法对垃圾焚烧飞灰中的4种重金属(锌、镍、铜、镉)的化学形态进行了研究。结果表明,金属Cd主要以底渣态的形式存在(占总镉质量的61.22%~62.41%),Ni,Zn以底渣态和铁锰氧化态为主,Cu主要以有机结合态为主(占总铜质量的60.97%~62.29%)。同时4种金属的生物有效性由高到低顺序依次为Ni,Cd,Zn,Cu。