中国西南典型地质背景区土壤重金属分布及生态风险特征

中国西南有22.3％的耕地重金属含量超标,区内广泛分布的峨眉山玄武岩和碳酸盐岩被认为是土壤中重金属的主要母质来源.目前,中国西南地区,尤其是峨眉山玄武岩分布区土壤重金属生态风险的研究程度仍有待提升,不同地质背景区(成土母岩)土壤中重金属含量、空间分布与生态风险缺乏对比.本文选择四川省典型地质背景区采集土壤样品,采用原子...     

陕西潼关县金矿矿区周边农田土壤重金属生态健康风险评价

为了解潼关金矿矿区早期粗放式的矿业活动对矿区周边农田土壤的重金属污染状况的影响以及对暴露人群的不良健康效应的评价,采用地质调查工程选取了矿区附近6块农田土壤为研究对象,通过X射线荧光光谱分析法测定了68个土壤样本中Cd、Hg、As、Pb、Cr、Cu、Ni、Zn等8种土壤重金属含量,采用地累积指数法、潜在生态危害指数法和...     

Release of heavy metals during weathering of the Lower Cambrian Black Shales in western Hunan,China

Weathering of heavy metal enriched black shales may be one of the most important sources of environmental contamination in areas where black shales are distributed. Heavy metal release during weathering of the Lower Cambrian Black Shales (LCBS) in western Hunan, China, was investigated using traditional geochemical methods and the ICP-MS analytical technique. Concentrations of 16 heavy metals, 8 trace elements and P were measured for samples from selected weathering profiles at the Taiping vanadium ore mine (TP), the Matian phosphorous ore mine (MT), and Taojiang stone-coal mine (TJ). The results show that the bedrock at these three profiles is enriched with Sc, V, Cr, Co, Ni, Cu, Zn, Pb, Th, U, Mo, Cd, Sb, Tl, and P. Based on mass-balance calculation, the percentages of heavy metals released (in % loss) relative to immobile element Nb were estimated. The results show significant rates of release during weathering of: V, Cr, Co, Ni, Cu, Zn, U, Mo, Cd, Sn, Sb, and Tl for the TP profile; Sc, Cr, Mn, Co, Ni, Cu, Zn, Pb, Th, Cd, and Sn for the MT profile; and Sc, Mn, Co, Ni, Zn, Th, Cd, Sn, and Tl for the TJ profile. Among these heavy metals, Co, Ni, Zn, Cd, and Sn show very similar features of release from each of the three weathering profiles. The heavy metals released during weathering may affect the environment (especially topsoil and surface waters) and are possibly related to an observed high incidence of endemic diseases in the area.     

Hydrochemistry of superficial waters in the Adoria mine area (Northern Portugal): environmental implications

The purpose of this work is to characterize the hydrochemical behavior of acid mine drainages (AMD) and superficial waters from the Adoria mine area (Northern Portugal). Samples of superficial and mine drainage water were collected for one year, bi-monthly, with pH, temperature, Eh, conductivity and HCO₃ determined in situ with chemical analyses of SO₄, Ca, K, Mg, Na, Cl, Ag, As, Bi, Co, Cu, Fe, Mn, Ni, Pb, Zn and Cd. In the mine, there are acidic waters, with low pH and significant concentrations of SO₄, and metals (Fe, Mn, Zn, Cu, Pb, Cd and Ni), while in the superficial natural stream waters outside the mine, the pH is close to neutral, with low conductivity and lower metal concentrations. The stream waters inside the mine influence are intermediate in composition between AMD and natural stream waters outside the mine influence. Principal Component Analysis (PCA) shows a clear separation between AMD galleries and AMD tailings, with tailings having a greater level of contamination.     

包头市典型工业区表层土壤中重金属污染状况及其潜在生态风险研究

为了解包头市典型工业企业对其所在地土壤中重金属含量的影响及污染现状,利用相关性系数对其表层土壤中7种重金属(Cu、Zn、Pb、Cr、Cd、Mn、Ni)来源进行研究,并采用内梅罗综合污染指数法和潜在生态危害指数对其污染状况进行评价。结果表明,7种重金属含量平均值均高于内蒙古土壤背景值,其中Cd、Mn、Ni超标率已达100%,而Cu、Pb、Zn的超标率分别为97%、93%和93%,只有Cr超标率较低(53%),污染程度依次为CdPbCuNiZnMnCr,其中Pb和Cd为重度污染,Cu、Zn、Ni为中度污染,Cr、Mn为轻度污染;Cu、Zn、Cr、Mn、Ni可能同时来自工业生产和交通运输两个源,而Pb和Cd除上述来源外,燃煤烟气的排放有较大贡献。潜在生态危害依次为CdPbCuNiCrZnMn,其中Cd的潜在生态风险最大,应予以高度重视,其他金属的风险均为轻微。     

固体聚合膜电解浓集法测量天然水中低含量氚的化学淬灭效应研究

固体聚合膜电解浓集法是浓缩氚含量较低(1 Bq/m~3)的天然水样的常用方法,但因水样自身含有杂质离子或电解装置聚合膜带入杂质进入浓集液,使浓集液偏酸性,在测量过程中易产生化学淬灭效应,导致氚的测量值偏低。本文研究了水样自身存在的杂质离子和聚合膜上残留的杂质离子、样品溶液的pH值及其电导率所产生的化学淬灭效应的影响,实验表明,为减少化学淬灭效应,提高测量低含量氚的准确性,需保证水样溶液呈中性,电导率≤1μS/cm,同时避免杂质沉积在聚合膜上。如果水样溶液的pH值偏酸性、电导率大于1μS/cm,可采用酸碱混合型离子交换树脂去除水样中自身的杂质;对于聚合膜引入的杂质,可在电解后的水样中加入微量氨水将其pH值调节至中性。     

Accumulation and risk assessment of heavy metals in dust in main living areas of Guiyang City,Southwest China

Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its risk. At each sampling site, 4-5 sub-samples were taken as a bulk sample. All samples were air-dried, ground, passed through a 0.105 mm nylon sieve, digested with HNO3-HC104 to determine the concentrations of Cd, Cu, Ni, Pb and Zn by ICP-MS, and digested with 1：1 aqua regia to determine As by AFS. The results show that the concentrations of As, Cd, Cu, Ni, Pb and Zn in dust of Guiyang City follow normal distribution with means of 16.1, 1.54, 138, 47.7, 129 and 479 mg/kg, respectively. Levels of As, Cd, Cu, Ni, Pb and Zn exceed the background level of soil in Guizhou Province by 33%, 96%, 100%, 78%, 96%, and 100%, respectively. Cd, Cu, Pb and Zn are heavily accumu- lated in dust of living areas with accumulation factors of 4.10, 5.12, 4.12 and 5.51, respectively. City square pos- sesses the highest geometric means of As, Cd, Cu, Pb, and Zn. The risks of heavy metal exposure to teenagers are not obvious and in an order ofAs〉Pb〉Cu〉Ni〉Zn （Cd）.     

Field application of calcite Dispersed Alkaline Substrate (calcite-DAS) for passive treatment of acid mine drainage with high Al and metal concentrations

Passive treatment systems are widely used for remediation of acid mine drainage (AMD), but existing designs are prone to clogging or loss of reactivity due to Al- and Fe-precipitates when treating water with high Al and heavy metal concentrations. Dispersed alkaline substrate (DAS) mixed from a fine-grained alkaline reagent (e.g. calcite sand) and a coarse inert matrix (e.g. wood chips) had shown high reactivity and good hydraulic properties in previous laboratory column tests. In the present study, DAS was tested at pilot field scale in the Iberian Pyrite Belt (SW Spain) on metal mine drainage with pH near 3.3, net acidity 1400–1650 mg/L as CaCO₃, and mean concentrations of 317 mg/L Fe (95% Fe(II)), 311 mg/L Zn, 74 mg/L Al, 20 mg/L Mn, and 1.5–0.1 mg/L Cu, Co, Ni, Cd, As and Pb. The DAS-tank removed an average of 870 mg/L net acidity as CaCO₃ (56% of inflow), 25% Fe, 93% Al, 5% Zn, 95% Cu, 99% As, 98% Pb, and 14% Cd, but no Mn, Ni or Co. Average gross drain pipe alkalinity was 181 mg/L as CaCO₃, which increased total Fe removal to 153 mg/L (48%) in subsequent sedimentation ponds. Unfortunately, the tank suffered clogging problems due to the formation of a hardpan of Al-rich precipitates. DAS lifetime could probably be increased by lowering Al-loads.     

承德中部土壤-黄芩系统重金属生物有效性及迁移累积特征

土壤重金属含量是影响黄芩产量和质量的重要因素。选取承德市中部金沟屯和五道岭两处黄芩种植示范区为研究区,采集表层土壤样品355件,黄芩样品30件,重金属形态样品15件。在分析土壤Mn、Zn、Cu、Cr、Cd、As、Pb、Ni、Hg、V、Co、Sb和土壤有机质含量（SOM）及pH值,黄芩Zn、Cu、Cr、Co、Cd、Pb、Ni、Hg和As含量基础上,采用描述性统计、地累积指数、主成分和RDA分析、重金属生物富集系数、生物活性系数和迁移系数等方法论述了土壤-黄芩系统重金属生物有效性及迁移累积特征。结果表明:金沟屯和五道岭区土壤各重金属累积程度总体属无-中度累积水平。五道岭Cu和Hg累积程度高于金沟屯区,其它元素累积程度低于金沟屯区。五道岭区表层土壤Cr、Cu和Cd含量超标率分别为2.82%、1.69%和1.13%;金沟屯区土壤Cd、Cr和Ni,五道岭区土壤Zn和Hg含量超标率均为0.56%。五道岭区黄芩Cu元素含量高于金沟屯区,Co和Cu元素生物富集强度高于金沟屯区,其它元素含量和生物富集强度则均低于金沟屯区。土壤Cd和Hg元素生物活性系数相对最高,Ni、Zn和Pb元素次之,Cu、Cr和As生物活性系数相对较低。金沟屯区根系土具有较低的pH值和较高的SOM含量,区内黄芩根部As、Cd、Cr、Ni、Zn和Pb元素BCF平均值高于五道岭区,Cu元素富集强度低于五道岭区。土壤重金属生物有效性和黄芩重金属生物富集强度受土壤pH和SOM含量影响,其中Cd和Cu元素受SOM含量影响最为明显。     

Interaction of organic acids and pH on multi-heavy metal extraction from alkaline and acid mine soils

Vegetation at mining sites can produce increased heavy metal leaching by the organic acids and protons originating from root secretion and litter degradation. Batch experiments were conducted to investigate the effects of organic acids and pH on the extraction of Pb, Cd, Zn and Cu from an alkaline mine soil (sampled from a mining site of Chenzhou City, Hunan Province) and an acid mine soil (sampled from a mining site of Daxin county, Guangxi Province). The results showed that in the presence of organic acids (acetic, oxalic, malic, fumaric, tartaric and citric acids) at pH 7, the extraction of Pb, Cd, Zn and Cu from the acid mine soil was much higher than that from the alkaline mine soil, in which only citric acid with higher concentration was capable of extracting some heavy metals. Citric acid had the strongest ability in extracting heavy metals, followed by oxalic acid. Heavy metal extraction dramatically decreased with increasing pH. Moreover, at low pH, oxalic acid promoted the risk of Cu leaching; at high pH, the leaching of Pb, Zn, Cd and Cu was enhanced by both oxalic and citric acids. This indicated that those plants, which can produce substantial citric acid or oxalic acid by root secretion and litter degradation, should not be selected for the revegetation of mining sites.     

雄安新区某金属冶炼区土壤重金属污染程度及风险评价

为支撑雄安新区土地资源科学管理,完善中国土壤污染评价体系,文章以雄安新区某废旧金属冶炼区为研究区开展地质调查,采集541件表层土壤样品,测定了土壤中的Cd、Hg、Pb、As、Cu、Zn、Cr、Ni八种重金属元素的含量和pH,采用主成分分析法研究重金属元素的组合及分布特征,通过单因子指数法、内梅罗综合指数法、地质累积指数法、潜在生态风险评价法和人体健康风险评价法对土壤重金属的污染程度及风险进行评价。结果显示：研究区土壤中Cu、Zn、Cd、Pb元素超标主要受冶炼活动影响,As、Hg元素高值异常主要由受唐河污染的地下水灌溉引起;单因子污染指数超标比例大小顺序为Cd>As>Cu>Zn>Pb>Hg>Cr=Ni;内梅罗综合指数评价结果显示54%的样品达到了污染水平;地质累积指数超标比例大小为Cd>Cu>Pb>As>Zn>Hg>Ni>Cr,Cu、Cd、Zn、Pb、As极重污染比例分别为13.5%、10.2%、9.1%、10.9%、17.2%;Cd和Hg是主要的生态危害元素,Cd中等-强生态危害比例为65.2%,Hg中等-强生态危害比例为71.3%;非致癌风险因子主要为As、Cr、Pb,95.2%样品对儿童的非致癌风险超过了1,29件样品中As对儿童的致癌风险超过10^-4,研究区土壤重金属对儿童具有较高的健康风险。     

Heavy metal geochemistry of the acid mine drainage discharged from the Hejiacun uranium mine in central Hunan,China

The acid mine drainage (AMD) discharged from the Hejiacun uranium mine in central Hunan (China) was sampled and analyzed using ICP-MS techniques. The analyzing results show that the AMD is characterized by the major ions Fe_Total, Mn, Al and Si, and is concentrated with heavy metals and metalloids including Cd, Co, Ni, Zn, U, Cu, Pb, Tl, V, Cr, Se, As and Sb. During the AMD flowing downstream, the dissolved heavy metals were removed from the AMD waters through adsorption onto and co-precipitation with metal-oxhydroxides coated on the streambed. Among these metals, Cd, Co, Ni, Zn, U, Cu, Pb and Tl are negatively correlated to pH values, and positively correlated to major ions Fe, Al, Si, Mn, Mg, Ca and K. The metals/metalloids V, Cr, Se, As and Sb are conservative in the AMD solution, and negatively-correlated to major ions Na, Ca and Mg. Due to the above different behaviors of these chemical elements, the pH-negatively related metals (PM) and the conservative metals (CM) are identified; the PM metals include Cd, Co, Ni, Zn, U, Cu, Pb and Tl, and the CM metals V, Cr, Se, As and Sb. Based on understanding the geochemistry of PM and CM metals in the AMD waters, a new equation: EXT = (Acidity + PM)/pH + CM × pH, is proposed to estimate and evaluate extent of heavy-metal pollution (EXT) of AMD. The evaluation results show that the AMD and surface waters of the mine area have high EXT values, and they could be the potential source of heavy-metal contamination of the surrounding environment. Therefore, it is suggested that both the AMD and surface waters should be treated before they are drained out of the mine district, for which the traditional dilution and neutralization methods can be applied to remove the PM metals from the AMD waters, and new techniques through reducing the pH value of the downstream AMD waters should be developed for removal of the CM metals.     

鄂东南铁山地区土壤-植物系统中重金属元素分布及富集特征

采用原子荧光光谱法和等离子体质谱法(ICP-MS)对鄂东南铁山地区主要河流流经区土壤、植物中重金属元素质量分数及其富集特征的研究表明,研究区西港河流域下游局部地段形成Cu、Zn、Ni、Cd、As重金属元素的土壤污染,东港河流域下游局部地段形成Cd、Cu、As、Pb、Zn重金属元素的土壤污染,植物中已经形成Cd、Zn元素的超量富集.其中土壤中重金属元素的富集主要与冶炼厂废水和尾矿坝渗漏水有关,而植物中重金属元素的富集则受土壤中重金属元素质量分数和植物吸收性能的双重控制.     

Uptake of Zn,Cu, Pb,and Cd by water hyacinth in the initial stage of water system remediation

The removal efficiency of water hyacinth for Zn, Cu, Pb and Cd after their entry into an undisturbed fresh water body was studied using minicosms placed within a reservoir. Variable parameters were water pH (6 or 8), single or multi-metal additions, and the plant biomass. The initial concentrations of Zn, Cu, Pb and Cd in water (500, 250, 250 and 50 μg/L, respectively) quickly decreased in the order Pb ≈ Cu ? Cd ≈ Zn in the first days. Metal removal was more efficient at pH 8 than at pH 6, and it was only slightly higher for single metals compared to multi-metal additions. After 8 days the remaining amounts of metals relative to their initial concentrations for multi-metal pollution treatments were 8% and 24% (Cu), 11% and 26% (Pb), 24% and 50% (Cd), and 18% and 57% (Zn) at pH 8 and pH 6, respectively. Increasing plant biomass promoted faster metal removal. The bioconcentration factor (the ratio of the metal concentration in whole plants to the initial metal concentration in water) exceeds 2000 for all metals (with the exception of Zn and Cd at pH 6). It was concluded that the water hyacinth can be successfully used for fast removal of metals in the initial stage of water body remediation.     

Zinc and nickel removal in simulated limestone treatment of mining influenced water

Mining influenced water (MIW) is often characterized by low pH (acid mine drainage) and high dissolved metal concentrations. Treatment of MIW is often required to mitigate these two characteristics. One option, which has traditionally been used only for pH neutralization, is limestone based treatment systems. However, there is field evidence that limestone systems are also effective at removing metals such as Zn and Ni. These field systems are often too complex to examine specific removal hypotheses, while certain modes of laboratory examination are too simplistic to be applied to field settings. Instead, the batch reactors used here were intentionally more complex to allow for the examination of how certain variables (pH, alkalinity, and primary metal concentrations) interact to affect Zn and Ni removal. The data herein suggest that one possible removal process for Zn and Ni is through surface interactions on the precipitated primary metals Fe and Al. The specific processes are complex and conditional, and were found to depend on pH, alkalinity, and total amount of primary metal present. Indeed the complex interplay between these variables led to an observed local maximum in Zn removal that would not be predicted from traditional surface complexation theory or observed from simpler experimental systems.     

金衢盆地典型地区土壤-稻米重金属含量及土壤酸碱度的影响研究

作物对土壤中重金属的吸收受作物种类、采集部位及土壤理化性质等多方面因素的影响。近年来,金衢盆地土壤酸化面积逐年增大,酸化程度逐渐加深,其对土壤-作物系统中重金属元素的活动影响尚不明确。本文基于金衢盆地典型地区264组根系土壤-稻米样品分析数据,开展土壤、作物的重金属含量特征及其影响因素的研究,重点讨论了土壤pH对作物吸收重金属的影响。结果表明：①264件土壤中多数重金属元素的变异系数大于0.5,As、Cd、Cr、Cu、Ni和Zn元素之间呈显著正相关（P<0.01）。土壤Cd超标样品23件,超标率为8.7%;As、Cr、Cu、Hg、Ni、Pb和Zn超标样品均未超过2件。②稻米中Cu、Zn与Cd含量呈显著正相关,Cd的富集系数（BCF）高于植物营养元素Cu、Zn。③稻米中Zn和Cu在P<0.1水平上与pH值呈显著正相关。Cd、Cr、Hg的BCF与pH值之间存在一定的负相关性。研究认为,适当调低土壤的酸碱度会削减土壤中Cd、Hg等重金属元素的活性,从而减少农作物对重金属的吸收转运。研究结果可为当地粮食安全生产决策提供科学数据,为土地管护提供参考依据。     

北京采矿废弃地植物修复重金属去除率研究

结合北京市采矿废弃地土壤地质环境情况,选取密云区西坨古金矿尾矿土、密云区冯家峪铁矿尾矿土和门头沟区桑峪煤矸石堆为研究对象,进行植物修复研究。共开展4种类型的修复试验,即选用高羊茅、紫花苜蓿和三叶草3种修复植物分别进行修复,同时与板蓝根、桔梗、波斯菊和薄荷等中草药进行混合种植修复,在植物生命周期的不同阶段采集样品分析测试。结果表明:在4种修复类型中,高羊茅对金矿尾矿土中Pb、Zn、Cr、Cd去除效果最好,最大去除率达到18.10%、14.57%、13.81%、18.12%;混合种植对铁矿尾矿土中Cr、Ni、As、Hg去除率达到4种修复类型的最大值,分别为14.81%、9.80%、37.25%、50%。三叶草对煤矸石修复效果最好,对Cr、Pb、Zn、Cd的去除率分别为5.65%、37.15%、15.15%、20%,是4种修复模式去除率的最大值。在生命周期的不同阶段,对比4种修复模式对采矿废弃地土壤中8种重金属的去除效果,均发现有去除率先升后降的现象,因此可对修复植物的进行定期收割,为提高植物吸附土壤重金属的效率,提供一定科学依据。     

Comparison of arsenic and heavy metals contamination between existing wetlands and wetlands created by river diversion in the Yellow River estuary,China

Samples were collected at 71 sites in the Yellow River Delta Natural Reserve in December 2010 to represent soil conditions before and after the Yellow River (YR) diversion. The As, Cd, Cu, Pb, Zn, and Ni concentrations were measured to determine metal contamination levels. Results suggest that Cd concentrations were significantly higher after the YR diversion than before. The As, Cd, Cr, Cu, Ni, Pb, and Zn soil contamination indices did not exceed contamination levels, although the heavy metal content increased after the YR diversion. The mean concentrations of these heavy metals were lower than the Class I criteria. Correlation analysis shows significant correlations between As and Cr, Cu, Ni, Pb, and Zn concentrations both before and after the YR diversion. However, no significant correlations were observed between heavy metal concentration and pH before the diversion, and no heavy metal concentration was correlated with salinity. The principal component analysis indicates that these trace elements, including As, were closely correlated with each other and therefore likely originated from shared pollution sources before the diversion. These results are useful for assessing the heavy metal contamination and proposing feasible suggestions to improve soil quality.     

Field multi-step limestone and MgO passive system to treat acid mine drainage with high metal concentrations

Passive treatment systems have become one of the most sustainable and feasible ways of remediating acid mine drainage (AMD). However, conventional treatments show early clogging of the porosity or/and coating of the reactive grains when high acidity and metal concentrations are treated. The performance of fine-grained reagents dispersed in a high porosity matrix of wood shavings was tested as an alternative to overcome these durability problems. The system consisted of two tanks of 3 m³ filled with limestone sand and wood shavings, and one tank of 1 m³ with caustic magnesia powder and wood shavings, separated by several oxidation cascades and decantation ponds. The system treated about 1.5 m³/day of AMD containing an average of 360 mg/L Fe, 120 mg/L Al, 390 mg/L Zn, 10 mg/L Cu, 300 μg/L As and 140 μg/L Pb, a mean pH of 3.08 and a net acidity of 2500 mg/L as CaCO₃ equivalent. The water reached pH 5 and 6 in the first and second limestone tanks, respectively (suitable to remove trivalent metals); and pH 8–9 in the MgO tank (suitable to remove divalent metals). After 9 months of operation, the system achieved an average removal of 100% Al, Cu, As, Pb, more than 70% Fe, about 25% Zn and 80% acidity. Goethite, schwertmannite, hydrobasaluminite, amorphous Al(OH)₃ and gypsum were the main precipitates in the two limestone tanks. Precipitation of divalent metals (Fe (II), Zn, and traces of Cd, Ni and Co) were complete inside the third tank of MgO, but preferential flow along the walls was responsible for its low treatment performance. Goethite, gypsum, Zn-schulenbergite and sauconite are the crystalline solid phases identified in the MgO tank.     

土壤中重金属元素电感耦合等离子体质谱定量分析方法的研究

分别采用HNO3-HF、HNO3-HF-HCl和HNO3-HF-H2O2三种消解体系,通过微波和PTFE密封罐电热板对土壤标准物质进行前处理,采用电感耦合等离子体质谱(ICP-MS)对样品中的重金属元素Cr、Ni、Cu、Zn、As、Cd和Pb进行定量分析。探讨了前处理试剂(主要为HNO3、HCl和HF)以及土壤基体效应对Cr、Ni、Cu、Zn、As、Cd和Pb定量分析的影响。研究结果表明,前处理试剂对Cr、Ni、Cu、Zn、As、Cd和Pb的定量分析具有不同程度的影响;对于土壤基体,在三种消解体系下均可观察到基体抑制效应;采用PTFE密封罐电热板消解方法前处理,待测元素及相同元素不同同位素的方法空白和检出限均较低,效果整体优于微波消解法。特别是HNO3-HF-HCl消解体系,通过选用52Cr、60Ni、65Cu、66Zn、75As和206Pb等同位素,重金属元素Cr、Ni、Cu、Zn、As、Cd和Pb的测定值均能保证在标准值的允许误差范围内,可以满足大批量土壤样品中重金属元素同时定量分析的需要,为高效准确地开展土壤的风险评估以及为土壤的修复治理提供科学依据。