湘中下寒武统黑色页岩土壤的地球化学特征

以湘中发育于下寒武统黑色页岩之上的土壤为研究对象,选择安化东坪、烟溪,桃江,宁乡等地的典型土壤及相应成土母岩,利用等离子质谱(ICP-MS)、X射线荧光光谱(XRF)等分析技术,对土壤、成土母岩(黑色页岩)的主量元素和微量元素(包括重金属元素、稀土元素等)进行了较系统的分析测定。结果表明,湘中下寒武统黑色页岩土壤风化作用强烈,风化指数CIA均在73以上。强烈的风化使得土壤具有明显贫CaO、Na2O,而富Al2O3、Fe2O3的化学组成特征。土壤因继承成土母岩(黑色页岩)的特征而富集Mo、Cd、Sn、Sb、U、V、Cr、Co、Ni、Cu、Zn、Tl、Pb、Th等多种重金属元素,其综合富集指数(EI值)平均在3以上,最高达17。地质累计指数(Igeo)评价结果显示,土壤重金属的富集已达到污染程度,土壤存在Cd、Mo、Sb、U、Sn、V、Cu、Tl、Ba等重金属的污染,并以Cd、Mo、Sb等重金属污染最强,达中度至极强污染程度。重金属与主量元素的相关性分析显示,土壤中的重金属主要赋存于黏土矿物和铁氧化物(针铁矿)等矿物相中,其中Ba、Sn、Th、Cu、Sc等主要赋存黏土矿物中;Zn、Ni、Mn、Co、Cd、Tl、Pb等则主要赋存于铁氧化物矿物(针铁矿)中;而Cr、V、Mo、Sb、U等则不受黏土矿物和铁氧化物矿物的控制。此外,不同地区土壤的Zr/Hf、Ta/Nb、Nd/Sm等元素比值相对稳定,依次为36.20、0.085、5.30(n=73),并与相应的成土母岩(黑色页岩)相应值基本一致。土壤与成土母岩具有相同的稀土配分型式,且成土过程中稀土元素不发生明显的分异。微量元素比值和稀土元素特征指示土壤中的重金属来自成土母岩(黑色页岩)本身,为自然污染源。     

广州市流花湖沉积物重金属污染特征及潜在生态风险评估

近年来重金属污染日益加重,对人类及水生态系统健康产生较大危害。本研究选择广州市典型城市湖泊——流花湖,利用地累积指数(Igeo)、潜在生态风险指数(RI)对沉积物中12种重金属的污染水平、垂向分布特征及其潜在生态风险进行评价,并通过多元统计分析对金属元素的来源进行解析。结果表明:①湖泊沉积物重金属含量(Mn、V除外)均显著高于区域土壤背景值,自下而上呈现先增加后减少的趋势;②地累积指数评价结果显示Cd、Zn、Sb、Cu、Pb和As这6种重金属污染较严重,其中Cd偏重度污染的状态(Igeo=3.89);③不同重金属元素污染水平有较大差异,Cd、Cu、Zn、Sb、Pb、As、Ni、Cr、Tl、Co的单个重金属污染指数(Cif)均为中等污染水平以上,而生态风险系数(Eif)表现为Cd(Eif=818.6)极严重等级,Sb(Eif=82.64)重度风险等级,其他10种重金属Eif均为轻度风险等级;④该湖RI指数变化幅度剧烈(105.85相似文献   

浙江省永康城市土壤重金属元素富集特征

永康169个城市土壤X荧光光谱测试分析表明:Cu、Mn、Co、Fe、Cr、Pb、Ni、Ti八种重金属元素的平均含量超过金衢盆地土壤背景值,且以工业用地类样品的富集程度最高。永康城市土壤重金属污染水平呈整体较轻,局部严重态势;各重金属元素的离散程度均较大,Cu为强变异元素,变异系数为152.93%,其他元素也为中强变异,表明永康城市土壤重金属元素含量在研究区内有较大差异。多元统计分析表明,Cr、Ni、Cu、Pb、Mn等重金属元素主要来源于当地的五金制造等工业和交通运输的影响;Fe、Ti、Co来源主要与成土过程中元素的积累有关,其中Fe有部分来源于五金生产。     

泉州市324国道泉州至塘头段路旁土壤中重金属来源分析

分析了泉州市324国道泉州至塘头段路旁土壤中14种重金属元素Sc、V、Fe、Mn、Co、Ni、Cu、Zn、As、Cd、Sn、Sb、Pb、Bi的含量,用富集因子和多元统计分析方法探讨了重金属的污染特征和可能来源。结果表明,Pb、Sn、Sb、Cd、Ni、Zn、Sc、Cu和Bi的含量均超过泉州市土壤背景值,污染较严重;Ni、Sb、Sn的高富集系数说明其受人类活动影响较大。相关分析和因子分析结果显示,上述14种元素主要有3个来源:Sn、Sb、Pb、Bi、Ni、Cu、Zn、Cd主要来源于交通污染;As、Sc、Fe来源于人类工业活动;而Co、Mn、V主要来源于土壤母质。聚类分析的结果也验证了因子分析的结果。     

珠江三角洲典型肝癌发病区土壤重金属富集特征分析及生态风险测度

测定了珠江三角洲经济区顺德典型肝癌发病区的29个表层土壤样品重金属含量,并用平均富集因子(AEFs)分析了研究区重金属元素污染程度,结果表明表层土壤重金属按富集程度可分为3类,严重富集(AEFs>5),主要有Cd、Hg;中度富集(AEFs=2~5),包括Zn、Cu、Ni、As、Co、Mn;轻微富集(AEFs<2),包括Fe、Cr、Pb、Se;Mo的富集程度最低,29个样点的EF值均小于0.2。进一步通过因子分析和聚类分析研究表层土壤中重金属的类别和来源,发现表层土壤中的17种重金属主要有5种不同组合,反映了5种不同的来源或迁移特性:因子1包括Ni、Li、V、Co、Cr、Fe和Al,因子2包括OM、Se和Ce,因子3主要包括Pb和Zn,因子4包括Cd、As和Mn,因子5由pH、Mo和Hg组成,其中因子1、2、4代表3种不同特性的自然源因子,因子3为交通及工业污染源因子,因子5为燃煤污染源因子。以广东省土壤背景值为参比标准进行的潜在生态危害评价结果表明,研究区表层土壤重金属潜在生态危害指数较高,总体以强度为主(RI>300),其中单项生态危害系数较高的是Hg和Cd,其余6种金属元素Pb、Cu、Ni、As、Cr属于轻微生态危害性。     

夏尔希里地区土壤重金属含量特征及空间变异分析

以夏尔希里地区为研究区,对土壤样品中Co,Cr,Cu,Mn,Ni共5种重金属的含量特征和空间分异规律进行了研究,采用单因子和内罗梅法分析土壤重金属的污染程度,并利用地统计学方法分析研究区土壤重金属的空间分异特征等。结果表明:研究区5种土壤重金属含量为:Mn > Cr > Cu > Ni > Co,5种重金属和有机质均属于中等变异强度;相关性分析结果显示:Co与Cu,Mn呈现显著相关;Cr与Cu,Ni有显著正相关;有机质与Cr,Mn,Cu,Ni均呈现正相关;重金属含量空间分异特征整体表现为绿洲区 > 荒漠区 > 山地森林区;重金属污染评价结果为:Co和Mn属于轻污染,Cr和Ni处于警戒线,属于尚清洁状态。     

夏尔西里自然保护区土壤重金属相关性分析及污染风险评价

为了探明夏尔西里自然保护区土壤重金属污染状况及相关性,沿山路蛇形布点采样,根据实地采样数据和试验数据,通过单因子污染指数分析法和潜在生态危害评价法,分别对夏尔西里自然保护区土壤重金属污染状况进行评价分析。结果表明:夏尔西里自然保护区重金属含量超过《土壤环境质量标准（GB15618—1995）》中一级土壤评价标准,Ni,Cr处于清洁状态;土壤中Pb,Zn,Co,Cu超标率分别为65%,50%,60%,85%;土壤中Hg,As超标率分别为90%,100%;8种重金属元素潜在生态危害系数顺序为:Hg > As > Cu > Pb > Co > Ni > Cr > Zn;Zn与Ni、Cu与Pb、Co与Cu的相关性达到显著性水平;Zn与Pb、Cr与Ni、Co与Pb、Co与Zn的相关性达到极显著性水平,元素有较高的同源性,重金属元素含量主要与成土母质有关,人为干扰对重金属元素含量影响较小,Hg,As元素与其他重金属元素相关性低或无相关性。     

贵州喀斯特山区锑冶炼厂对农业土壤污染特征的影响及风险评价

以贵州省晴隆县大厂镇喀斯特山区废弃锑冶炼厂周围的农田土壤为研究对象,研究了距离冶炼厂烟囱不同距离12个表层土壤样点和5个典型土壤剖面中重金属含量。结果表明表层土壤主要污染元素为Sb、Zn、Pb、Hg、As和Cu,分别是贵州省土壤背景值的58.58、11.96、7.99、7.45、6.70和1.60倍;土壤剖面中8种主要重金属元素垂直变化规律各异,不同层次重金属含量（(Pb除外）)均表现为：距离冶炼厂烟囱越近含量越高,平均含量由高到低依次为：Mn>As>Sb>Cu>Cr>Pb>Hg>Cd,均明显高于全国土壤背景值的平均水平。其中,As、Cr、Mn和Hg平均含量差异较大,与对照相比,主要污染元素为Sb、Hg和As,Hg和As分别为国家土壤环境质量Ⅱ级标准的4.7倍、4.4倍;其次是Cd和Cu,分别为国家Ⅱ级标准的3.0倍、2.7倍。相关分析和聚类分析表明,土壤主要受重金属Cr、Cd、Cu、Sb和As复合污染。采用单因子污染指数和内梅罗综合污染指数法对该地区农田土壤进行了环境风险评价,各层次Cr、Cd、Cu和As含量均超标,污染严重,综合污染指数在1.21 ~ 14.83之间,以重度污染为主;耕作层污染程度由高到低顺序为：大厂村（(冶炼厂）)>中心街村>碧康组>田坝组,均属于重度污染,表层污染土壤（(0 ~ 20 cm）)种植农作物存在一定的风险。     

三峡库区重金属含量空间分布及污染状况

[目的] 对三峡库区坡面土壤与消落带沉积泥沙中重金属含量特征开展研究,为该区重金属污染评价提供理论与数据支持。[方法] 在三峡库区选取53个采样点,分析区域内坡面土壤与消落带沉积泥沙中Cr,Cu,Pb,Zn,Mn 5种重金属元素的含量,利用单因子污染指数法、内梅罗综合指数法、地累积指数法和潜在生态风险指数法开展污染状况评价。[结果] 研究区域内重金属含量平均值大小依次为：Mn>Zn>Cr>Cu>Pb,仅Cu,Zn和Mn存在污染。Zn和Mn在消落带沉积泥沙与坡面土壤中皆富集,而Cu仅在坡面土壤中富集。研究区域内重金属在空间分布上呈上、下游高,中游低分布。单因子污染指数法表明,研究区内仅存在Zn （P_ia=1.07）的轻度污染与Mn （P_ia=2.65）的中度污染。研究区域内梅罗综合指数为2.93,为中度污染。根据地累积指数法,研究区域内仅存在Mn轻度污染,其余重金属皆为无污染。Cr,Cu,Pb,Zn,Mn的潜在生态危害皆为轻微生态危害;研究区域的综合生态危害指数为14.09,为轻微生态危害。[结论] 研究区域内Cr含量主要受到研究区地质背景影响,而Cu,Pb,Zn和Mn含量同时受到地质背景与人类活动的影响。研究区内存在Mn和Zn污染,且有轻微生态危害。     

有色金属采选冶基地周边土壤中重金属纵向分层研究

土壤中重金属元素的纵向分布特征是土壤自身理化性质和外界环境影响下的综合反映,探寻这个特征对于了解土壤中重金属污染程度和研究修复治理技术意义重大。本研究通过对大型有色金属采选冶企业下风向7种不同土地利用类型的土壤进行纵向采样分析,对重金属元素Zn、Cu、Pb、Cr的纵向分布及累积指数进行了研究,为进一步探寻重金属元素的环境行为及来源,了解重金属污染现状,制定修复方法提供技术参考。研究结果表明:研究区域土壤中重金属含量整体上受到了外源干扰,不同用地类型与不同深度土层重金属含量大小关系不一,证明了不同植被与不同土壤性质对重金属迁移有影响;研究区域重金属整体下移较为活跃,Cr元素表现最为明显;土壤样本中重金属含量均高于内蒙古土壤背景值,重金属元素有不断富集的趋势。     

Standards for the contents of heavy metals and metalloids in soils

In line with the present-day ecological and toxicological data obtained by Dutch ecologists, heavy metals/metalloids form the following succession according to their hazard degree in soils: Se > Tl > Sb > Cd > V > Hg > Ni > Cu > Cr > As > Ba. This sequence substantially differs from the succession of heavy elements presented in the general toxicological GOST (State Norms and Standards) 17.4.1.02-8, which considers As, Cd, Hg, Se, Pb, and Zn to be strongly hazardous elements, whereas Co, Ni, Mo, Sb, and Cr to be moderately hazardous. As compared to the general toxicological approach, the hazard of lead, zinc, and cobalt is lower in soils, and that of vanadium, antimony, and barium is higher. The new sequence also differs from that of the metal hazard in soils according to the Russian standard on the maximal permissible concentration of mobile metal forms (MPC_mob): Cu > Ni > Co > Cr > Zn. Neither an MPC_mob nor an APC_mob has been adopted for strongly hazardous thallium, selenium, and vanadium in Russia. The content of heavy metals in contaminated soils is very unevenly studied: 11 of them, i.e., Cu, Zn, Pb, Ni, Cd, Cr, As, Mn, Co, Hg, and Se, are better known, while the rest, much worse, although there are dangerous elements (Ba, V, Tl) among them.     

Contamination of soils with heavy metals and metalloids and its ecological hazard (analytic review)

According to the present-day ecotoxicologic data, hazardous heavy metals/metalloids form the following sequence in the soil: Se > Tl > Sb > Cd > V > Hg > Ni > Cu > Cr > As > Ba. This sequence differs from the well-known series of the hazardous heavy elements, in which the danger of Pb and Zn is exaggerated, whereas that of V, Sb, and Ba, is underestimated. Tl also should be included in the list of hazardous elements in the soil. At present, the stress is made on the investigation of heavy metals/metalloids in agricultural soils rather than in urban soils, as the former produce contaminated products poisoning both animals and humans. The main sources of soil contamination with heavy metals are the following: aerial deposition from stationary and moving sources; hydrogenic contamination from the industrial sewage discharging into water bodies; sewage sediments; organic and mineral fertilizers and chemicals for plant protection, tailing dumps of ash, slag, ores, and sludge. In addition to the impact on plants and groundwater, heavy metals/metalloids exert a negative effect on the soil proper. Soil microorganisms appear to be very sensitive to the influence of heavy elements.     

Effect of Non-Vehicular Sources on Heavy Metal Concentrations of Roadside Soils

Soils along highway environments typically contain high concentrations of heavy metals because of non-point contamination sources, most commonly vehicle exhaust and wear of vehicle parts. Pb, Zn, Cu, Cr, Sb, Ba and Ra concentrations of soils along roadways with very low traffic volumes in a rural portion of San Patricio County, Texas, have been studied in order to distinguish the effects of a point source (an industrial waste landfill) from the effects of traffic. The highest concentrations of Zn, Cr, Sb, Ba and Ra were detected in soils along the access road to the landfill. The association of high Ba values with high Ra values suggests that the most probable sources of this contamination were oilfield waste from storage tank bottoms, which were disposed of in landfill waste pits and were also spread over roads within the landfill to decrease dust. Outside the landfill along a different roadway, a second contamination area which was characterized by very high Ba but low Sb and Ra concentrations compared to background values, has been detected. Drilling mud spill is the most probable source of this contamination. The contaminations caused by these two point sources differ from typical vehicle-sourced contamination in two ways: their areal extent was limited and contaminants were not typical for highway environments (like Ba and Ra). Like vehicular contamination, however, these areas were confined to the immediate vicinity of the roadways. Another difference is that Pb in most vehicle-contaminated areas is strongly bound to the soil constituents, mostly organic matter, whereas the point source Pb was found to be readily exchangeable and to have no association with organic matter.     

Contamination of Urban Soils in an Area of Northern France Polluted by Dust Emissions of Two Smelters

The contamination of 27 urban topsoils has been assessed around two lead and zinc smelters (Metaleurop Nord and Umicore) in the North of France. Eighteen trace elements have been analysed (Ag, As, Bi, Cd, Co, Cr, Cu, Hg, In, Ni, Pb, Sb, Se, Sn, Tl, Th, U and Zn). The investigation included the study of the vertical distribution of Cd, Pb and Zn as indicators of pollution. It was shown that Cd, In, Pb, Sb and Zn were major pollutants followed in lesser quantities by Ag, Bi, Cu and Hg. In addition, As, Ni, Se, Sn and Tl were present at levels slightly higher than regional agricultural values. The other elements (Co, Cr, Th and U) were at endogenous levels. The observations have highlighted the strong heterogeneity of the physico-chemical parameters of urban soils and the existence of heavy contamination of the under layers by Cd, Pb and Zn. A potential transfer of metals from the topsoil to the deeper layers and especially Cd and Zn, is not excluded. Indeed the soil rework is not the only factor explaining contamination level of the deeper layers of the studied soils. The comparison of the studied element concentrations in urban soils with nearby local agricultural values shows that the dust emission originating from the Metaleurop and Umicore smelters were not the only source of contamination. Thus a large contamination of the studied urban soils by Sb and In could be explained by domestic combustion of coal for heating.     

Assessment of the Contamination of Cultivated Soils by Eighteen Trace Elements Around Smelters in the North of France

Ag, As, Bi, Cd, Co, Cr, Cu, Hg, In, Ni, Pb, Sb, Se, Sn,Tl, Th, U and Zn contamination of cultivated surfacehorizons has been assessed around two lead and zincsmelters in the North of France. The verticaldistribution of Ag, As, Bi, Cu, Hg, Se, Sb and Tl inthe soils has also been examined. The soils around thelead and zinc smelter at Noyelles-Godault arecontaminated by Ag, As, Bi, Cd, Cu, Hg, In, Ni, Pb, Sb,Se, Sn, Tl and Zn. The original concentration in themost contaminated soils may be multiplied by a factorof around 2 to 100, according to the element. Cadmium,Pb and Zn are the most abundant contaminants. The Pband Zn concentrations are correlated to those of theother contaminants, with the exception of Se. Aroundthe Auby zinc smelter, there is a contamination by thesame elements, but in different proportions, inaddition to Cr contamination. Contamination by Se canreach a depth of around 1 m, whereas contamination byAg, As, Bi, Cu, Hg, Sb and Tl is confined to the top 30cm. Although the contaminant content in most soilsdepends on the distance from the plant, Secontamination would appear to vary to a greater extentaccording to the physico-chemical soil conditions.     

Levels and Bioaccessibilities of Metals in Dusts from an Arid Environment

The elemental composition and bioaccessibility of trace metals have been determined in a variety of geosolids (soils, road dusts and house dusts) from an arid, coastal region (Dhahran, Saudi Arabia). Concentrations of many elements reflected those of the local geology, ascertained by analysis of desert sand. Several trace metals (e.g. Cu, Sb, Zn, Pb, Tl and Sn) were moderately enriched in both road and house dusts, reflecting external and internal (household) anthropogenic sources. For a given trace metal, bioaccessibilities, assessed using a physiologically based extraction test, were broadly similar across the range of geosolids. Median values for a simulated gastric phase ranged from less than 10% (Ba, Cu, Cr, Ni and V) to more than 50% (As, Cd, Sb, Sn and Tl), and for a subsequently simulated intestinal phase from less than 15% (Ba, Cr, Cu, Ni, V and Zn) to more than 50% (As, Cd, Sb, Tl and U). Results suggest that the levels and bioaccessibilities of trace metals in dusts from arid environments are controlled by the dilution of anthropogenic particulates by variable (but significant) proportions of fine, baseline sand.     

Accumulation Capacities of Particulate Matter in an Acrocarpous and a Pleurocarpous Moss Exposed at Three Differently Polluted Sites (Industrial, Urban and Rural)

The aim of this study was to compare the capacity of two morphologically different moss species to accumulate elements when exposed to three different types of air pollution (rural, urban and industrial). Transplants of Pseudoscleropodium purum and Ceratodon purpureus were exposed for 6 months, and the concentrations of 18 elements (Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, As, Mo, Cd, Sn, Sb, Ba, La, Pb and Bi) in the mosses samples were analysed by inductively coupled plasma–mass spectrometry. On the whole, the metals were accumulated by mosses, and this accumulation was correlated with concentrations in the atmospheric particles. Whereas P. purum is to be preferred for Al, Cu, Zn and Fe monitoring, C. purpureus was most efficient at accumulating Mo, Ti, V, As, Sn, La and Pb. In both species, a phenomenon of saturation was observed during the exposure at the most contaminated site (industrial).     

Geochemical investigations on atmospheric precipitation in a medium-sized city (Göttingen,F.R.G.)

The concentration of 27 elements was investigated in 10 samples of precipitation from Göttingen, collected during May and September 1972. Göttingen is a non-industrial town of 130000 inhabitants, situated in a rural area, and essentially all the dissolved and undissolved material in rainwater is locally derived. Elemental concentrations in freshwater and shale are used for comparison with the dissolved elements in precipitation and the undissolved residue. The two phases have been separated after evaporation (concentration factors: 15 to 25-times). Phosphorous, Zn, Mn, and Pb are enriched in rainwater, while Si, Mg, Na, Ca, Cl, Fe, Hg, K, Li, and Al are depleted relative to average freshwater. Sulfate, Cd, and Cu have similar concentrations in rain and freshwater. The factors of accumulation between elements in residue and average shale are calculated after normalization to the Al-value. They are: ? 100 for Ag, Hg, Pb; between 10 and 20 for Zn, Cd, P, Cu, Mo; > 2 for Cr, Bi, Ni, Ba, Ti, V ; between 0.9 and 2.0 for Rb, K, Na, Li, Mg, Mn, Fe, Si, Ca; and 0.5 for Tl. The trace element accumulation is due to different anthropogenic sources: combustion of liquid petroleum fuels contributes to Ph, V, Ni, Mo, Hg, and sulfate, combustion of coal to Ba, sulfate, and chloride, and to the. readily volatile elements such as Hg, Cd, Tl, Bi, and Ag, combustion of refuse to Ag, Bi, Pb, Cd, Hg, Zn, Cr, Cu, Ba, and Mo in highly variable amounts. Fertilizers and road salts change the chemistry of soils and indirectly supply P, alkali and alkaline-earth metals to the fly dust. Modest industrial activity is responsible for high Cu and Cr concentrations. Despite the appreciable accumulation of some toxic elements, the precipitation in Göttingen is relatively pure compared to other areas. Favorable geologic conditions around Göttingen decrease the negative influences of potentially harmful airborne elements. The high carbonate content in the dust neutralizes the anthropogenic acids in the rainwater. Furthermore, the toxic trace elements are diluted, especially in the center of Göttingen, by a large amount of airborne dust.