基于不同土地利用方式的深圳市农用地土壤重金属污染评价（Evaluation of the Heavy Metal Pollution in Different Agricultural Soils of Shenzhen City）

为探讨深圳市农林土壤重金属的污染现状,分菜地、果园、林地和荒地等4种不同的土地利用类型,共采集了52个表层土壤样品,采用原子吸收法测定了其重金属Cu、Pb、Zn、Cd、Cr和Ni全量,单项污染指数法和内梅罗综合指数法评价了6种重金属在土壤中的污染现状.评价结果显示,部分土壤样点存在较为严重的重金属污染,Cd的污染最为严重,Cu的污染最轻;不同用地类型下的污染等级不同,荒地处于尚清洁(警戒限)水平,菜地和林地处于轻度污染水平,果园处于中度污染水平,全市农用地土壤处于轻度污染水平.     

长期温室菜地土壤重金属累积状况及污染评价

为研究温室菜地种植对土壤重金属含量的影响,以中国农业大学曲周实验站长期定位试验土壤为研究对象,分析了土壤重金属含量累积变化特征并对其进行了污染评价.结果表明,与河北省重金属土壤背景值相比,0—40 cm土壤重金属Cd、Cr、Cu、Zn、Pb的含量均有不同程度的累积,其中Cd和Cu累积程度最高;除As和Ni外,0—20 cm土壤重金属Cd、Cr、Cu、Zn、Pb的含量均有随种植年限的增长而增加的趋势;0—20 cm土壤Cd、Cu、Zn含量均分别显著高于20—40 cm土壤Cd、Cu、Zn含量(P0.05),0—20 cm土壤As含量显著低于20—40 cm土壤As含量;0—20 cm土壤中,重金属Cu、Pb、Ni、Cr与土壤p H呈显著负相关关系(P0.05).根据《土壤环境质量标准》(GB15618—1995)二级标准限值评价,2016年曲周实验站温室菜地0—20 cm土壤重金属环境质量处于轻污染状态,其中重金属Cd是主要的污染因子.     

包头市南海湿地土壤重金属污染评价及来源解析

包头市南海湿地位于中国西北地区的高纬度寒旱区,具有独特的河流湿地生态系统。以南海湿地土壤为研究对象,对湿地28个点位表层土壤(0~20 cm)中As、Cd、Cr、Cu、Ni、Mn、Pb、Zn 8种重金属进行检测分析,采用环境质量指数与Hakanson环境生态潜在风险指数相结合的方法,探讨土壤中8种重金属的累积污染现状及潜在生态风险,利用相关性分析、主成分分析和聚类分析区分了南海湿地重金属的来源,以期为南海湿地土壤环境保护提供理论依据。结果表明,As、Cd、Cr、Cu、Ni、Mn、Pb和Zn重金属平均值分别为75.18、1.27、56.98、111.18、87.67、622.71、54.10和209.33 mg·kg~(-1)。以包头市南海公园树木林土壤重金属含量为评价基准,南海湿地土壤重金属普遍超标,研究区域所有样方中As、Cd、Cu、Mn和Pb均超标,Cr有64.29%的样点超标,Ni有96.43%的样点超标,Zn有89.29%的样点超标。单因子污染指数表明,Cd处于中度污染;As、Cu、Pb和Zn处于轻度污染;Cr、Ni和Mn处于轻微污染。农田区和景观大道两侧处于重污染水平,鱼塘区和湿地植物区处于中污染水平。潜在生态风险指数表明,Cd处于强风险等级;As、Cr、Cu、Ni、Mn、Pb、Zn处于低风险等级。;研究区整体上都属于中等风险等级。来源解析表明:As、Cd、Cu、Ni、Mn的来源受到周边工业活动和农业活动的影响;Pb和Zn的来源与道路交通有关,Pb还受到工业活动的影响;Cr来源与土壤母质和农业活动有关。     

污灌区土壤-小麦系统重金属污染、迁移和积累--以开封市化肥河污灌区为例

以开封市化肥河污灌区为例，研究了土壤-小麦系统重金属(Cd、Pb、Cr、Cu、Zn、Ni和AS)污染、迁移和积累规律。结果表明，该区土壤重金属污染较为严重，所有样点的综合污染指数均大于1，其中Cd和AS污染最为严重，其平均质量分数远远超出了土壤环境二级标准值。在该区土壤上种植的小麦也表现出一定程度的重金属累积，但其茎叶和种子重金属质量分数差别较大；在所有种子样品中，Zn质量分数都未超标，AS、Cr和Pb质量分数部分到达了较高的残留水平，Cd质量分数则远远超出了国家食品限量卫生标准。依据重金属迁移累积率(βi)，小麦对As和Cr的吸收能力较低，而对Ni和Cd的吸收能力较高；在所有小麦样品中，除Cu外，茎叶对同一重金属的平均富集能力均大于种子。     

武汉东湖高新技术开发区土壤重金属污染状况及影响因素

在武汉市东湖高新技术开发区采集土壤样本136个,测定Cd、Cu、Ni、Pb、Zn和Cr的含量,发现Cd平均含量超过湖北省背景值,并且在研究区大片区域都超过了国家环境质量二级标准.Cu平均含量接近背景值,而其它元素均低于背景值,但部分区域仍有富集.地统计分析显示6种重金属自相关性较弱,重金属含量高值主要分布于研究区中部以及西北部.从空间分布看,Cd、Cu、Ni和Cr的富集可能主要来源于区内企业生产排放.Pb和Zn含量主要由自然因素决定,外界基本没有输入,部分区域富集的Pb可能由交通因素造成,Zn的局部累积可能来自于农业措施.综合污染指数显示区内整体存在污染,需要采取必要的措施进行治理.     

潍坊市菜地重金属调查与环境风险评价研究

科学评估菜地土壤重金属污染状况对有机种植规划布局、指导农业种植结构调整具有重要的现实意义,也可为土壤环境风险防控和污染土壤修复提供科学依据。在山东省潍坊市全境蔬菜主产区随机采集32个设施菜地和15个露地菜地样本,应用电感耦合等离子体质谱测定了Cr、Ni、Cu、Zn、Cd、Pb等元素以及用原子荧光光度计测定As、Hg质量分数;依据GB15618—2008,对土壤重金属超标情况进行评价,采用生态风险指数和潜在地积累指数等方法进行了重金属环境风险及污染程度评价。结果表明:Cr、Ni、Cu、Zn、Cd、Hg等元素质量分数平均值分别是山东省土壤环境背景值的1.13、1.16、1.27、1.62、3.21和2.11倍,表明重金属存在富集现象;各个元素质量分数平均值均低于国家二级标准值,但Cd、Ni、Cu、Zn的点位超标率分别为21.3%、8.51%、2.12%、2.12%;潜在生态风险指数评价结果显示,菜地土壤处于中等生态风险,其中设施菜地处于中等生态风险,露地菜地处于低生态风险;所有点位Cr、Ni、Cu、Zn、As、Pb均为低生态风险,而Cd、Hg分别有97.8%和80.8%的点位处于中等生态风险及其以上水平。地积累指数评价结果表明,设施菜地Cd、Hg、Zn处于轻度-中等污染水平,露地菜地Cd、Hg处于轻度-中等污染水平,其他元素均无污染;所有点位中,Hg、Cd、Zn、Ni、Cr、Cu、Pb受污染比例分别为78.7%、63.8%、42.6%、17.0%、14.9%、12.8%、2.1%。整体上,潍坊市菜地土壤能够满足有机种植的条件,但存在一定数量点位的污染,其中Cd点位污染比例最大,可能会成为限制该区域有机种植的主要因素。     

电子废弃物拆解区周边农田土壤重金属污染评价及成因解析

深入了解电子废弃物拆解、倾倒及扩散引发的土壤环境问题,有助于根据土壤重金属污染程度及其潜在生态风险实现拆解区周边农田土壤的分类分级管理和科学合理利用。在浙江台州(国内电子废弃物三大拆解基地之一)某典型电子废弃物拆解区的拆解点、倾倒点及周边农田随机采集12个土壤样本,测定了土壤重金属(Cd、Cu、Cr、Ni、Pb、Zn)质量分数与污染指数,并开展了生态风险评估与成因推测研究。从研究区土壤重金属单项污染指数(以所有样点的平均值计)来看,Cd、Cu、Pb、Zn为重度污染,Cr与Ni分别为中度与轻微污染,其中Cd、Pb与Cu分别具有极强、强和中等生态危害,而Ni、Cr、Zn具有轻微生态危害。从具体样点来看,电子废弃物拆解点和倾倒点土壤重金属污染指数最高分别达164.2和152.9(均为重度污染),其潜在生态风险指数最高分别达2 685和6 914(均为很强生态危害);57.14%的农田样点土壤重金属已达中度至重度污染水平,28.57%的农田样点土壤重金属生态危害达中等级别。主成分分析与相关性分析结果显示,研究区土壤重金属污染存在两条主要扩散途经,首要的是电子废弃物拆解产生的粉尘与焚烧产生的飞灰随大气沉降而产生的污染,次要的是拆解点与废渣倾倒点经雨水冲刷、淋溶下渗、地表径流所造成的污染。结果表明,研究区土壤重金属污染较为普遍,且以Cd、Pb、Cu为主,Zn、Cr、Ni次之;电子废弃物拆解与处置过程中重金属的扩散途径以空气传输为主、雨水迁移为辅。     

江苏苏北湿地土壤重金属污染特征及评价

本文研究了苏北盐城湿地土壤重金属Pb、Cu、Cr、Cd、Zn污染状况,并采用相关性分析和主成分分析对土壤重金属的来源进行了分析,同时,通过内梅罗综合污染指数法、地质累积指数法和Hakanson潜在生态风险指数法对土壤重金属的污染情况进行了评价.结果表明,研究区的土壤中Pb、Cu、Cr、Cd和Zn的平均含量分别为26.28、27.55、57.71、1.04、70.05 mg·kg-1,除了Cd有97.1%超过土壤环境质量二级标准,其余均未超过二级标准.除Pb含量分布变化幅度较小外,其余4种重金属含量分布变化幅度都较大.相关性分析和主成分分析表明研究区域的Pb、Cu、Cr、Zn存在相关性,它们可能来自于相似来源,主要来源于工业排放;Cd与其它重金属无相关性,表明来源不同,可能主要来自于农业化肥的施用.内梅罗综合污染评价法及地质累积指数法结果表明,各重金属污染程度从大到小的顺序为:CdCuZnPbCr.土壤样品的内梅罗综合污染指数P综合=6.11,说明总体上该区域土壤已达到重度污染等级.研究区域的综合潜在生态风险指数RI为261.71,总体处于中度生态风险等级,并且Cd是主要贡献因子.     

天津东南部某区域不同土地利用方式下土壤重金属的累积特征

为分析天津东南部某区域不同土地利用方式下土壤中重金属(As、Cd、Cr、Co、Cu、Pb、Ni、V、Zn、Hg)的累积程度,在该研究区工业用地、居住用地和农业用地3种土地利用方式下的土壤表层采集样品进行重金属含量分析,并运用单因子指数法和内梅罗综合指数法对重金属累积状况进行评价。结果显示,在工业用地土壤中累积程度较高的重金属为Cd、As、Co、Ni和Zn,在居住用地中为Cd、As、Co、Zn和Pb,而农业用地土壤为Cd、As、Co和Zn。研究区土壤重金属状况总体表现为Cd为重度累积,As为中度累积,Co、Cu、Pb、Ni、V和Zn为轻度累积,Cr和Hg基本处于背景值水平。土壤重金属内梅罗综合指数评价结果表明,研究区大部分地区的土壤重金属累积程度都达到中度及以上水平,内梅罗综合指数平均值由高到低依次为农业用地、工业用地和居住用地。与国内其他地区相比,该研究区Cd、As和Co累积程度明显偏高。     

浙北地区农用地和建设用地土壤重金属污染及潜在生态风险评价

为了研究浙北地区农用地和建设用地2种不同土地利用方式下土壤重金属污染情况,采集并分析了159个表层(0～20 cm)土壤样品中的Cd、Hg、As、Pb、Cr、Cu、Zn、Ni 8种重金属含量,采用主成分分析法(PCA)进行来源解析,并运用单因子污染指数法、污染负荷指数法、潜在生态风险及预警指数法进行综合评价。结果显示,农用地和建设用地8种重金属元素的平均质量分数均未超过相关评价标准筛选值,但均超过浙江省土壤环境背景值,其中农用地中Cd和Hg污染,建设用地Cd、Cu、Pb和Zn污染明显。研究区农用地和建设用地土壤重金属综合污染负荷指数(PLI)均为轻度污染状态,且对土壤污染贡献率最大的重金属元素均为Cd,可为研究区土壤重金属的污染防治、风险管控提供依据。研究区农用地除Cd为中度污染外,其他7种重金属均为轻微污染;建设用地Cd为重度污染,Cu、Zn、Pb为轻度污染,Cr、Hg、As、Ni为轻微污染。研究区农用地土壤Ni、Zn、Cu、Cr主要受土母质影响,Cd和Pb主要来源可能为交通运输,Hg和As主要受人类活动影响;建设用地Cd、Hg、Pb、Cr、Cu、Zn、Ni可能具有不同程度的相同来源...     

Heavy metals,occurrence and toxicity for plants: a review

Metal contamination issues are becoming increasingly common in India and elsewhere, with many documented cases of metal toxicity in mining industries, foundries, smelters, coal-burning power plants and agriculture. Heavy metals, such as cadmium, copper, lead, chromium and mercury are major environmental pollutants, particularly in areas with high anthropogenic pressure. Heavy metal accumulation in soils is of concern in agricultural production due to the adverse effects on food safety and marketability, crop growth due to phytotoxicity, and environmental health of soil organisms. The influence of plants and their metabolic activities affects the geological and biological redistribution of heavy metals through pollution of the air, water and soil. This article details the range of heavy metals, their occurrence and toxicity for plants. Metal toxicity has high impact and relevance to plants and consequently it affects the ecosystem, where the plants form an integral component. Plants growing in metal-polluted sites exhibit altered metabolism, growth reduction, lower biomass production and metal accumulation. Various physiological and biochemical processes in plants are affected by metals. The contemporary investigations into toxicity and tolerance in metal-stressed plants are prompted by the growing metal pollution in the environment. A few metals, including copper, manganese, cobalt, zinc and chromium are, however, essential to plant metabolism in trace amounts. It is only when metals are present in bioavailable forms and at excessive levels, they have the potential to become toxic to plants. This review focuses mainly on zinc, cadmium, copper, mercury, chromium, lead, arsenic, cobalt, nickel, manganese and iron.     

Sources, spatial variation, and speciation of heavy metals in sediments of the Tamagawa River in Central Japan

Sediments of the Tamagawa River in central Japan were studied to explain the spatial variation, to identify the sources of heavy metals, and to evaluate the anthropogenic influence on these pollutants in the river. Sediment samples were collected from 20 sites along the river (five upstream, four midstream, and 11 downstream). Heavy metal concentrations, viz. chromium, nickel, copper, zinc, lead, cadmium, and molybdenum, in the samples were measured using inductively coupled plasma-mass spectroscopy. The chemical speciations of heavy metals in the sediments were identified by the widely used five-step Hall method. Lead isotopes were analyzed to identify what portion is contributed by anthropogenic sources. The total heavy metal concentrations were compared with global averages for continental crust (shale) and average values for Japanese river sediments. The mean heavy metal concentrations were higher in downstream sediments than in upstream and midstream samples, and the concentrations in the silt samples were higher than those in the sand samples. Speciation results demonstrate that, for chromium and nickel, the residual fractions were dominant. These findings imply that the influence of anthropogenic chromium and nickel contamination is negligible, while copper, zinc, and lead were mostly extracted in the non-residual fraction (metals in adsorbed/exchangeable/carbonate forms or bound to amorphous Fe oxyhydroxides, crystalline Fe oxides, or organic matter), indicating that these elements have high chemical mobility. The proportion of lead (Pb) isotopes in the downstream silt samples indicates that Pb accumulation is primarily derived from anthropogenic sources.     

Sources,spatial variation,and speciation of heavy metals in sediments of the Tamagawa River in Central Japan

Sediments of the Tamagawa River in central Japan were studied to explain the spatial variation, to identify the sources of heavy metals, and to evaluate the anthropogenic influence on these pollutants in the river. Sediment samples were collected from 20 sites along the river (five upstream, four midstream, and 11 downstream). Heavy metal concentrations, viz. chromium, nickel, copper, zinc, lead, cadmium, and molybdenum, in the samples were measured using inductively coupled plasma-mass spectroscopy. The chemical speciations of heavy metals in the sediments were identified by the widely used five-step Hall method. Lead isotopes were analyzed to identify what portion is contributed by anthropogenic sources. The total heavy metal concentrations were compared with global averages for continental crust (shale) and average values for Japanese river sediments. The mean heavy metal concentrations were higher in downstream sediments than in upstream and midstream samples, and the concentrations in the silt samples were higher than those in the sand samples. Speciation results demonstrate that, for chromium and nickel, the residual fractions were dominant. These findings imply that the influence of anthropogenic chromium and nickel contamination is negligible, while copper, zinc, and lead were mostly extracted in the non-residual fraction (metals in adsorbed/exchangeable/carbonate forms or bound to amorphous Fe oxyhydroxides, crystalline Fe oxides, or organic matter), indicating that these elements have high chemical mobility. The proportion of lead (Pb) isotopes in the downstream silt samples indicates that Pb accumulation is primarily derived from anthropogenic sources.     

污泥土地利用对土壤中重金属形态的影响

土地利用是资源化利用城市污水厂污泥的有效途径，随污泥中的营养成分一起进入土壤中的还有其中的重金属元素，它们有可能成为一种环境安全的隐患。本实验所用的土壤为污泥经过无害化及稳定化处理后，与上海潮滩沙土按不同比例(干污泥质量比)混配而成。种植前后分别对沙土、污泥及混配土的重金属含量及形态进行测试。选择几种花卉植物，如菊花(Calendula officinalis）等进行植物种植试验，一个生长季后对植物中的重金属含量及形态进行测试。应用Tessler连续提取法，对污泥中的重金属进入土壤后，土壤中重金属的含量、赋存状态等方面的规律进行研究，发现污泥的土地利用会明显增加土壤中的重金属含量，而且重金属的形态也有明显的变化，可交换态和碳酸盐结合态的重金属含量有明显的增加；如长期使用，则必须采取相应的措施，以消除有害的影响。     

Assessment of Trace Metals in the Sediments From the Coastal Zone of Alexandria, Egypt

Freshly deposited surface sediments from the Alexandria coastal zone were collected and analysed in 1995 for their trace metal concentrations. Metal concentrations in the sediments vary between sites within a wide range for copper, zinc, iron, lead, chromium and cadmium. the statistical analysis between the metal concentrations and the different constituents (organic carbon, total nitrogen, silt, clay and total iron) showed significant correlations. the enrichment factors for the sediments ranged between 3 and 4-fold for copper, chromium and zinc and reached up to 9-fold for lead and 113-fold for cadmium. the highest index for cadmium and lead may be attributed to the anthropogenic inputs from the surrounding area, where they are highest in lower discharge areas.     

Assessment of Trace Metals in the Sediments From the Coastal Zone of Alexandria,Egypt

Freshly deposited surface sediments from the Alexandria coastal zone were collected and analysed in 1995 for their trace metal concentrations. Metal concentrations in the sediments vary between sites within a wide range for copper, zinc, iron, lead, chromium and cadmium. the statistical analysis between the metal concentrations and the different constituents (organic carbon, total nitrogen, silt, clay and total iron) showed significant correlations. the enrichment factors for the sediments ranged between 3 and 4-fold for copper, chromium and zinc and reached up to 9-fold for lead and 113-fold for cadmium. the highest index for cadmium and lead may be attributed to the anthropogenic inputs from the surrounding area, where they are highest in lower discharge areas.     

Trace metals in the roadside mountain soils of Sierra Nevada,Spain

The investigations were made to determine the total contents of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Cr in the roadside soils and rocks of the Sierra Nevada Mountains in Spain. There were differences in both the age and lithology of the bed-rock in the study area. The surface soil layer is primarily enriched with lead in relation to the bed-rock, but zinc, manganese, and cadmium also occur.Lead, zinc and cadmium concentrations show a decrease with increasing distance from the road, whereas the levels of iron, manganese, copper, nickel and chromium do not show such a variation. The change in lead and zinc concentrations with increasing distance from the road is related to the topography of the area immediately adjacent to the road. On the descending slopes the concentrations of these metals remain unchanged or increase with the increasing distance from the road, whereas on the ascending slopes they show a clear decrease.     

Total and bioavailable metals in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo): relation to genetic variation in plant populations

Knowledge of total and bioavailable metal contents in soil is important for regional risk assessment and management. The main objective of the present study was to analyse the concentrations of metals in soils in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo). Genetic variation of plant populations was investigated to assess the potential impact of metal contamination on forest sustainability. The levels of copper, cobalt, zinc, arsenic, and lead were significantly higher (up to 200-fold) in mining sites in the Lubumbashi compared to the most highly contaminated Sudbury sites. The nickel content in soil samples from Lubumbashi was much lower compared to Sudbury region samples. Only 3.5% and 4 % of total copper and nickel, respectively, were phytoavailable, with values of 6%, 5.7%, 3.6%, and 5.4% for cobalt, magnesium, manganese, and zinc, respectively. There were significant positive correlations between total metal and phytoavailable metal concentrations for copper (r=0.99), nickel (r=0.86), cobalt (r=0.72), strontium (r=0.71), and zinc (r=0.66). Although genetic variation was high in Picea glauca populations from the Sudbury region, no association was found between metal contamination levels and genetic variation within and among the P. glauca populations.     

Elemental composition of Jamaican foods 1: A survey of five food crop categories

The concentrations of 27 elements in Jamaican food categories consisting of fruit, legumes, leafy and root vegetables and other root crops are reported. The main analytical techniques used were neutron activation analysis and flame and graphite furnace atomic absorption spectrophotometry. The results are compared, where possible, with values from Denmark, the United Kingdom, the United States and Nigeria, and with some regulatory limits. Over 75% of the results for antimony, arsenic, barium, cerium, thorium and uranium were below the respective sample detection limits but even among these, some of the maximum values observed indicate that further examination may be useful for those foods grown in the regions of highest uptake and consumed in large amounts. The other elements reported are bromine, cadmium, calcium, caesium, cerium, chromium, copper, europium, hafnium, iron, lanthanum, lead, magnesium, manganese, phosphorus, potassium, rubidium, scandium, samarium, sodium, strontium, thorium, uranium, and zinc. Many of these elements occur at concentration levels above those reported from the other countries but it seems unlikely that most of these will contribute significantly to public health risk. However, at this stage cadmium clearly appears to be the element of greatest concern in the Jamaican food chain. The observed range of cadmium concentrations suggests that factors such as land selection, coupled perhaps where necessary, with suitably modified agricultural practices, is a feasible way to reduce the cadmium content of certain local foods.     

Flooding and the Distribution of Selected Metals in Floodplain Sediments in St. Maries, Idaho

The link between sediment contamination and flooding is not well established, since flooding may exacerbate problems by spreading pollutants throughout the floodplain, or alternatively may dilute contaminants in source areas. To determine the substance of such relationships, the pattern of sediment contamination was examined in a small Idaho town following flooding in 1996. Four heavy metals were tested, nickel, chromium, zinc and copper, in 97 soil samples obtained from sites across the floodplain of the St. Joe River. Flood history and land-uses at each sample site were noted. Results showed that contamination levels generally were not high, with flood areas having lower concentrations than non-flood areas. A stronger relationship could be argued for land-use, with higher concentrations of contamination associated with some industrial sites. High levels of contamination were also found in several samples taken from recreational areas. Further research looking at the potential sources of contamination in relation to characteristics of the flood hydrology would seem pertinent.