大型金属矿山不同环境介质中重金属元素化学形态分布特征——以甘肃金昌市和白银市为例

重金属元素在环境介质中的存在形态及各形态比例是决定其迁移性和生物可利用性的重要因素.采用BCR法连续提取过程对大型金属矿山周围土壤和水体沉积物中Cd、Cr、Cu、Ni、Pb和Zn化学形态的分析结果表明,土壤和水体沉积物中不同重金属元素化学形态分布有很大差异.总体而言,Cd以弱酸提取态为主(约占60%),Cr以残渣态为主,占90%以上,Cu以可氧化态为主(约占60%),Ni和Pb以可还原态为主,分别约占50%和60%,Zn以残渣态为主,约占45%.不同区域土壤中重金属元素各形态质量分数之和依次为厂区外围>尾矿坝旁>农田,各形态分布也与总量具有相似的变化趋势.金昌市矿山环境介质中重金属以Cu和Ni为主,白银市以Cd、Cu和Pb为主,重金属元素的生物可利用态和潜在可利用态质量分数高,平均约占各金属,总量的60%～90%,对周围环境具有很大的潜在生态危害性.     

北京城区土壤中Hg、Pb、Cd、Cu及Zn化学形态及环境效应

为弄清北京城区土壤中Hg、Pb、Cd、Cu及Zn五种重金属元素的化学形态分布特征,系统采集了126件城区表层土壤样品,采用连续提取法对重金属元素各化学形态含量进行了测定。结果表明:土壤中土壤中Hg、Pb、Cd、Cu、Zn含量差异显著。Hg元素以残渣态和强有机结合态为主,Cd元素离子交换态、碳酸盐结合态、残渣态、铁锰氧化物结合态含量较高,Pb、Cu、Zn元素以残渣态、铁锰氧化物结合态为主。Hg元素的有效态含量最低(不足1%),现情况下不会对环境造成污染;Cd元素的有效态含量最高(40%),生物有效性和潜在生态危害性较大,运用植物修复技术对其治理为经济有效的方法;Pb、Cu、Zn有效态含量较低(约10%),生物有效性和潜在生态危害性均有限。各元素形态与全量之间相关程度虽有差别,但基本呈正相关关系。     

基于形态学分析铅锌矿不同功能区土壤重金属元素的分布特征及污染评价

为掌握尤溪铅锌矿区土壤重金属元素分布特征和污染现状,通过采集尤溪铅锌矿不同功能区0~20cm表层土壤样品,测定土壤中Pb、Zn、Cd、Cu、Cr 5种重金属元素的总量及其化学形态,分析不同功能区土壤重金属污染及分布特征,同时采用次生相与原生相比值法(RSP)进行污染评价。结果表明,尤溪铅锌矿不同功能区土壤中Pb、Zn、Cd含量均超过国家土壤环境质量三级标准,废弃冶炼区土壤Cd、Cu、Pb、Zn含量均最高,分别为标准值的14.78、1.13、3.73、1.34倍,采矿区Cr含量最高,但未超过标准限值。重金属形态结果表明,相比其他元素,Cd弱酸提取态所占比例最高,Cu可交换态比例最高,Pb、Zn、Cr以残渣态为主。RSP法评价表明,不同重金属的污染程度表现为:Cu(1.15)Cd(0.80)Pb(0.59)Zn(0.57)Cr(0.54);不同功能区土壤重金属污染表现为:尾矿库区冶炼区废弃冶炼区采矿区。SPEF法评价表明,尤溪铅锌矿区受人为污染明显,采矿区和尾矿库区Zn污染最为严重,冶炼区和废弃冶炼区Pb污染最为严重,功能区污染顺序为:尾矿库区冶炼区废弃冶炼区采矿区。     

炼锌固体废渣中重金属(Pb、Zn)的存在状态及环境影响

利用XRD、TEM/EDS和连续提取实验研究了土法炼锌固体废渣中重金属的矿物学特征及不同粒度中重金属的相态分布特征。与通常发现的重金属一般富集在小粒径废渣中的情况不同,本工作所研究的废渣样品中大粒径废渣与细粒径废渣相似,甚至有更高的金属含量。化学形态研究表明,冶炼过程形成的矿物(或玻璃质)集合体和堆积后的风化过程形成的次生矿物是废渣中重金属存在的主要化学相。同时发现Pb的残渣态很少(0.39%～15.75%),而Zn的残渣态较高(14.3%～46.2%),这可能与冶炼工艺所形成较多Zn的硅酸盐矿物有关。尽管可交换态Pb、Zn在不同相态中的相对比例非常小(Pb0.03%～1.30%;Zn0.03%～3.30%),但其绝对含量却比一般土壤或沉积物要高(Pb1.5～385μg/g;Zn3～590μg/g)。由于重金属可交换态有比其他化学相态更高的活动性和生物可利用性,因此,对环境有较大的潜在影响。废渣样品的微束分析表明,Pb在废渣中见有金属Pb存在形式或呈纳米金属Pb颗粒包裹于其他矿物或铁合金及熔球集合体中。同时不排除有Pb的碳酸盐矿物存在的可能。而以硅锌矿Zn2(SiO4)、锰硅锌矿(Zn,Mn)2犤SiO4犦和纤维状的丝锌铝石Zn8Al4犤(OH)8(SiO4)5犦·7H2O等矿物形式存在以及Fe、Mn等的铝硅酸盐形式存在的Zn,可能是导致Zn的残渣态较高的原因。与连续提     

云南沘江流域农田土壤重金属Pb、Zn、Cd、As的地球化学特征

以流经中国铅锌矿储量最大的兰坪金顶铅锌矿区的澜沧江支流——沘江周围农田土壤为研究对象,通过实地调查采样、室内实验测定和统计分析等方法,测定分析了土壤中Pb、Zn、Cd、As的含量及其化学形态分布,以探讨矿产开发对农田土壤重金属含量的影响。结果表明:(1)沘江流域农田土壤中的重金属蓄积量大,以国家《土壤环境质量标准》(Ⅱ级)衡量,Pb、Zn、Cd、As含量超标率分别为66.667%、91.667%、100%、16.667%,污染程度为Cd﹥Zn﹥Pb﹥As;(2)土壤中Pb和Cd的化学形态均以水溶态为主,活性大,迁移能力强,水溶态元素能够直接进入生态链,通过植物吸收进入食物链将给人类健康造成一定的威胁。而Zn和As化学形态分别以铁锰氧化物结合态和残渣态为主,这两种形态在一般环境条件下较稳定,迁移能力弱;Pb和Cd的环境有效态(水溶态、离子交换态、碳酸盐结合态、腐殖酸结合态之和)含量较高,如果发生酸雨或酸性矿山废水的排出,它们的环境有效态会大量增加,对流域具有潜在的危害;(3)土壤中Pb、Zn、Cd、As含量分布和化学形态分布,整体上均为随着与矿区的距离增大而降低的趋势,分布曲线分为单峰状、双峰状两类。另外,Cd、Pb、Zn的化学形态分布与总量分布趋势基本一致,As的腐殖酸结合态、残渣态与总量分布一致。     

铅锌矿山开发导致的重金属在环境介质中的积累

以连续提取法和相关性分析研究了土法冶炼锌、铅锌和矿山开采导致的重金属在废渣及环境介质土壤、溪流沉积物中的积累，并分析了其环境危害性。结果显示，贵州赫章土法炼锌导致的重金属Pb、Zn、Cd在环境介质中的积累相当高。水城杉树林铅锌矿山开采引起的重金属积累则相对较低，但也明显高于背景值；土壤和沉积物中的铁矿物对重金属有强烈的固定作用。除残渣态外，Pb、Zn在土壤、炼锌废渣中主要呈铁锰氧化物结合态，沉积物中则为碳酸盐结合态。可交换态Pb、Zn含量变异较大，但在炼锌废渣、土壤中含量明显高于河流沉积物，暗示铅锌矿开发对土壤环境的潜在危害更大。     

北京某金矿区土壤重金属污染特征及风险评价

使用网格布点法采集144个浅层土壤样品,分析测定As、Cd、Cr、Cu、Hg、Ni、Pb和Zn共8种重金属元素的含量.通过多元统计方法、土壤重金属含量空间分布及极值点分析,揭示了金矿地区土壤污染特征及污染风险.结果显示,区内浅层土壤重金属含量超过该地区背景值较高的元素为Pb、As、Cd,与背景值接近的元素为Cr与Ni.重金属污染风险较高的区域集中分布在金矿开采区、尾矿库、选矿厂及其下游约1.5 km范围内,主要污染元素为As、Cd、Pb、Cu、Zn,基本不存在Cr、Ni、Hg污染.相关性与主成分分析结果显示,矿山开采及冶炼是土壤重金属污染的主要来源.污染物的主要迁移途径为金矿开采区、尾矿库及选矿厂的废渣和尾矿析出的重金属通过废渣及尾矿堆的孔隙下渗进入底垫土壤,通过地表径流进入下游土壤中.     

北京某金矿区土壤重金属污染特征及风险评价

使用网格布点法采集144个浅层土壤样品,分析测定As、Cd、Cr、Cu、Hg、Ni、Pb和Zn共8种重金属元素的含量.通过多元统计方法、土壤重金属含量空间分布及极值点分析,揭示了金矿地区土壤污染特征及污染风险.结果显示,区内浅层土壤重金属含量超过该地区背景值较高的元素为Pb、As、Cd,与背景值接近的元素为Cr与Ni.重金属污染风险较高的区域集中分布在金矿开采区、尾矿库、选矿厂及其下游约1.5 km范围内,主要污染元素为As、Cd、Pb、Cu、Zn,基本不存在Cr、Ni、Hg污染.相关性与主成分分析结果显示,矿山开采及冶炼是土壤重金属污染的主要来源.污染物的主要迁移途径为金矿开采区、尾矿库及选矿厂的废渣和尾矿析出的重金属通过废渣及尾矿堆的孔隙下渗进入底垫土壤,通过地表径流进入下游土壤中.     

金昌市铜镍矿区周围土壤中重金属的迁移特征

对金昌矿区不同区域土壤5~20 cm层中重金属各化学形态及活性态的迁移行为进行了研究,结果表明：土壤中重金属不同化学形态迁移率不同,弱酸提取态、可还原态、可氧化态和残渣态平均迁移率分别为0.13、0.51、0.30和0.54。重金属总量和活性态（包括弱酸提取态、可还原态、可氧化态）迁移率也表现出很大差异,尾矿区土壤Cr总量迁移率较高为0.65,而其活性态迁移率较低为0.26,Ni与Cr迁移特征完全相反,总量迁移率为0.26,而活性态迁移率为0.67;农田土壤中Pb总量迁移率低而活性态迁移率高,Ni与Zn特征相似,总量迁移率高而活性态迁移率相对较低;大棚地土壤中重金属迁移率均较低,Cu和Ni活性态几乎未发生向下迁移。可见,重金属的迁移与其化学形态分布关系密切,与重金属总量的迁移率相比,活性态迁移率能够更有效地反映出土壤中重金属的迁移特征和潜在危害性。     

三峡库区澎溪河消落带土壤中重金属形态分布与迁移特征研究

消落带是水域与陆地的过渡地带,对水环境有着至关重要的影响。本文以三峡库区消落带面积最大的澎溪河流域作为研究区域,采集消落带土壤及其沿岸土壤样品,分析重金属形态分布特征,并使用地质累积指数法和风险评价准则(RAC)对重金属污染程度及生态风险进行评价。研究表明,消落带土壤中Pb、Cu、Cr、Cd、Zn和Ni平均含量分别为68.70、36.96、55.10、0.68、108.26、31.68 mg/kg,污染程度依次为CdPbZnCuNiCr,以Cd和Pb污染较为突出,普遍高于长江干流土壤,远高于重庆地区土壤。Cd的RAC值为20.62%,呈中等环境风险;其形态稳定性最差,以可还原态和酸提取态为主。Pb、Cu、Cr、Zn、Ni的RAC值为5.45%~10.0%,环境风险较低;且均以残渣态为主,占总量的54.69%~83.05%。以消落带沿岸土壤为对照,消落带形成后土壤中各重金属总量均有不同程度升高,且不同重金属在其增量部分的形态存在差异,Cr和Ni的增量部分以残渣态为主,Cd、Pb、Zn的增量以非残渣态为主。研究发现,由于受到水域与陆地污染源的双重影响,澎溪河流域重金属具有由沿岸向消落带沉积富集的趋势。     

Characteristics of distribution and chemical speciation of heavy metals in environmental mediums around Jinchang mining city,Northwest China

Heavy metal contamination was the main environmental problem around the Jinchang Ni–Cu mine area of Gansu, Northwest China. The concentration of heavy metals (Cr, Cu, Ni, Pb, and Zn) in various environmental mediums around the Jinchang Ni–Cu mine area were analyzed using atomic absorption spectrometry (AAS). The different chemical speciation of heavy metals was extracted using BCR (European Community Bureau of Reference) sequential extraction procedure, and the concentration of chemical speciation of each heavy metal was measured by inductively coupled plasma-atomic emission spectrometry. The results showed that Cu and Ni were the most important heavy metal pollutants in various mediums including cultivated soils, dust on slagheap surfaces, tailings, and sediments in waste water drains. In the tailings and sediments, the concentrations of Ni were obviously higher than those of Cu, whereas, in the soil and dust, the concentrations of Cu were higher than those of Ni. Analysis of chemical speciation indicated that Cr and Zn were mainly in residual fraction; Cu was mainly in oxidizable fraction; Ni was mainly in reducible fraction and acid soluble fraction; and Pb was mainly in reducible fraction and residual fraction. The extent of contamination of various environmental mediums was different because the heavy metals were derived from different sources. Furthermore, the mobility of various heavy metals was different because of the different distribution of chemical speciation.     

Distribution and sequential extraction of some heavy metals in urban soils of Guiyang City,China

Sixty-two soil samples collected from different functional zones of Guiyang were analyzed for total concentrations and sequential extraction of Cr, Cu, Pb, Zn and Cd by ICP spectrometry. The average total concentrations ofCr, Cu, Pb, Zn and Cd in the soils of Guiyang were 92.9, 51.6, 44.1,139.3 and 0.28 mg/kg, respectively. The soils have been polluted by Cr, Cu, Pb, Zn and Cd to some extent in comparison with the background values of Guiyang. Significant differences were recognized in the concentrations of Cr, Cu, Pb, Zn and Cd in different functional zones. As for the sequential extraction, Cr, Cu and Zn were present mainly in the residual fraction, and Pb was present mainly in the oxidizable fraction. The reducible fraction of Cd accounts for 47.5%, and the residual fraction is lowest. The mobility and bioavailability of heavy metals follow the order of Cd〉Pb〉Cu〉Cr〉Zn.     

贵阳城市土壤重金属元素形态分析

选取贵阳市62个代表性的表层土壤样品,分析了其重金属元素的含量和存在形态.结果表明,贵阳城市土壤中5种重金属元素(Cr、Cu、Pb、Zn和Cd)的含量较高,且变化较大.表层土壤中Cr、Cu、Zn主要以残渣态形式存在,Pb主要以可氧化态形式存在.Cd可还原态含量高达47.5%,残渣态含量最低,说明Cd较活泼,具有潜在的环境影响能力.     

大亚湾表层沉积物重金属元素形态特征、控制因素及风险评价分析

为了解大亚湾表层沉积物中重金属的污染状况,对大亚湾海域23个点位表层沉积物中7种重金属元素（Cr、Ni、Cu、Pb、Zn、Cd、As）的质量分数、形态特征、来源控制因素以及潜在生态风险进行了研究。采用优化BCR提取法分析重金属元素赋存形态,并依据各种重金属元素的形态特征与沉积物基质属性进行了相关因子分析,了解其分布的控制因素。结果表明：大亚湾沉积物重金属元素呈现环带状分布特征,从岸向湾内逐渐减小;重金属元素质量分数的高值区主要分布于大鹏澳、哑铃湾及范和港附近;重金属元素赋存形态中Cr、Ni、Cu、Zn、As主要以残渣态存在,Pb主要以可还原态存在,Cd主要以酸提取态存在;7种重金属元素各自非残渣态所占比率从大到小为Pb(78.83%)、Cd(78.65%)、Cu(48.54%)、Zn(48.10%)、Ni(38.31%)、Cr(28.43%)、As(27.76%),即Pb最高,As最低,表明Pb的迁移性最强;通过因子分析,大亚湾重金属主要为沿岸自然风化产物的输入,其次为工业废水及养殖污水。运用酸提取态风险评估法对重金属元素潜在生态风险进行评价,发现研究区所选重金属元素综合风险评价Cd为高风险,其余重金属为中-低风险等级。     

Geochemical features of heavy metals in core sediments of northwestern Taihu Lake, China

Sequential core sediments from northwestern Taihu Lake in China were analyzed for grain size, organic carbon and heavy metal content. The sediments are composed of organic-poor clayey-fine silts. The chemical speciations of Cu, Fe, Mn, Ni, Pb, and Zn were also analyzed using the BCR sequential extraction procedure. Cu, Fe, Ni, and Zn are mainly associated with the residue fraction; Mn is concentrated mainly in exchangeable/carbonate fraction and residue fraction; and Pb mainly in Fe/Mn oxide fraction and organic/sulfide fraction. The exchangeable/carbonate fractions of Cu, Fe, Ni, Zn and Pb are lower. The fractions of Ni, Pb and Zn bound to the Fe/Mn oxide have significant correlations with reducible Mn; the organic/sulfide fractions of Cu, Mn, Ni, Pb, and Zn have significant correlations with TOC. The extractable fractions of Cu, Mn, Ni, Pb, and Zn are high at the top 4 cm of the core sediments as compared to those in the deeper layers, showing the anthropogenic input of heavy metals is due to rapid industrial development. The heavy metal pollution history of the sediments has been recorded since the late 1970s, determined by the result of ^137Cs dating.     

Distribution and chemical speciation of heavy metals in the surficial sediments of the Bak?r?ay and Gediz Rivers, Eastern Aegean

The pollution of aquatic ecosystem by heavy metals has assumed serious proportions due to their toxicity and accumulative behaviour. The toxicity and fate of the water borne metal is dependent on its chemical form and therefore quantification of the different forms of metal is more meaningful than the estimation of its total metal concentrations. A five-step sequential extraction procedure was applied for the determination of the distribution of seven elements (Pb, Cr, Cu, Mn, Zn, Ni, Fe) in sediment samples collected from Bakır?ay and Gediz Rivers. According to this study, the results of metals are mostly retained in the residual, oxidizable and reducible fractions. Based on the chemical distribution of metals, we found that Cr, Zn, Cu and Ni are the most non-mobile metals. Pb is the metal that showed the highest percentages in the residual and reducible fractions. Mn is present in the higher percentages in the reducible and carbonate fractions. However, Fe is present in the greatest percentages in the residual fraction, which implies that these metals are strongly linked to the sediments. The risk assessment code as applied to the present study shows that about 12.3–26.9 and 15.7–33.5% of manganese at most of the sites exist in carbonate fraction in the Bakır?ay and Gediz Rivers, respectively. Therefore, Mn comes under the medium risk category in the Bakır?ay and high-risk category in the Gediz River. Speciation pattern of Cu, Zn, Pb, Cr, Ni, Fe shows low to medium risk to aquatic environment health in both rivers.     

长江口海域表层沉积物重金属元素赋存形态特征

通过长江河口地区水下表层沉积物样品多种化学元素的赋存形态分析测试数据,综合分析重金属元素的赋存形态特征。研究结果显示：镉、汞、铅残渣态所占比例均小于50%,锌、砷、铬、铜、镍残渣态占比均大于50%;8个元素的残渣态与全量呈显著正相关关系。沉积环境和沉积物粒径对重金属元素赋存形态具有重要影响。沉积物的物质来源、矿物组成特征、水动力作用与沉积物粒度和物理化学条件等是长江口地区表层沉积物重金属元素赋存形态的主要控制因素。     

太湖沉积物中重金属的地球化学形态及特征分析

用连续提取法分析了太湖沉积物5种重金属的地球化学形态,对地球化学形态的组成和地理特征进行了分析研究.重金属地球化学形态配分的共同特点是可交换态最低,残渣态最高.两种形态中Cd的可交换态最高,Cr的残渣态最高,可交换态最低.Cd的碳酸盐态较高,Cr的最低;Pb、Cd的Fe-Mn氧化态较高,Cu的偏低;Cu的有机态最高,Cd的最低;Zn的地球化学形态比例大都处于中间.地域上变化较大的元素是Cd和Cu,变化不明显的元素有Pb和Zn.化学成分中Fe2O3、MnO与重金属地球化学形态的相关性最好,TOC与Cu的形态相关系数最高.综合对比分析表明,太湖沉积物重金属的生物有效性以Cd为最高,其次为Pb.     

Sources of very high heavy metal content in soils of volcanic island (La Réunion)

The objective of this study was to conduct an inventory of heavy metal concentrations (Cd, Cr, Cu, Hg, Ni, Pb and Zn) in the soils of La Réunion. 39 sampling sites were selected to cover the distribution of soils of the island. The results show that soils of La Réunion are rich in heavy metals: most of them exceed the French standard values beyond which sewage sludge spreading is not authorized. To identify the sources of heavy metals, we used: (i) the relationship between the heavy metal content in soils and the origin of the volcanic parent material; (ii) the comparison of heavy metal content between cultivated and uncultivated soils; and (iii) the heavy metal distribution in soil profiles. Cd and Pb evolution in soil profiles indicate an impact of human activities. High Hg concentrations in soils can be explained by the volcanic activity of the island. For Cr, Cu, Ni and Zn, we demonstrate that high concentrations in soils are mainly determined by the natural pedo-geochemical background.     

The effect of traffic on levels,distribution and chemical partitioning of harmful metals in the street dust and surface soil from urban areas of Tehran,Iran

Due to the explosive industrialization and rapid expansion of the population in many parts of the world, heavy metals are released into the environment continuously and pose a great risk on human health. Street dust and surface soil samples from very heavy, heavy, medium and low traffic areas and a natural site in Tehran, Iran, were analyzed for some physicochemical features, total and chemical fractionating of selected metals (Zn, Al, Sr, Pb, Cu, Cr, Cd, Co, Ni and V) to investigate the influence of traffic on their mobility and accumulation in the environment. The pH, electrical conductivity (EC), carbonates and organic carbon contents were similar in soil and dust samples from the areas with same traffic. The traffic increases EC contents in dust/soil matrixes, but has no effect on concentrations of metals in soil samples. Rises in metal levels with traffic were found in dust samples. Moreover, the traffic increases the percentage of both acid-soluble and reducible fractions, which are related to Pb and Zn. The mobilization of Cu, Zn, Pb, Cr in dust samples was easier than in soil. The speciation of metals except Cd is mainly affected by physicochemical features in soil, though total metals affected the speciation in dust samples (except chromium and nickel).