改性Mg(OH)2对多种重金属污染土壤的修复效果

为了研究一种高效的多种重金属污染土壤修复剂,本文采用了一种具有OH^-缓释功能的改性Mg（OH）₂,通过重金属污染土壤稳定化修复实验,探讨了改性Mg（OH）₂对污染土壤中多种重金属（Pb、Cd、Cu、Zn）的稳定效率及对多种重金属形态分布的影响。结果表明,投加改性Mg（OH）₂对土壤中多种重金属均有稳定作用,对Pb、Cd、Cu、Zn的稳定效率分别为72.42%、34.53%、87.64%和97.65%,且改性Mg（OH）₂的投加使重金属交换态质量明显减少、残渣态质量增加,进一步提高了重金属的稳定性,降低了重金属生物有效性;另外,改性Mg（OH）₂具有OH^-缓释性,可使土壤长期保持一定的碱性,是一种经济有效的土壤修复剂。     

Effects of pH, alkalinity and bedrock chemistry on metal concentrations of springs in an acidified catchment (Ecker Dam, Harz Mountains, FRG)

Thirty-four springs were sampled on five different source rocks in the upper Ecker watershed of the Northern Harz Mountains (Germany) four times during the course of 1995. The analyses included 41 cations and the major anions. Approximately 90% of the rocks in the upper Ecker watershed are low in basic cations, which inhibit the neutralisation of hydrogen-ion loading. As a consequence, the concentrations of Al, Fe, Mn, Zn, Pb, Y, Ce, As, La, Nd, Cd, Be, Co, Sb, Pr, Gd, Dy, Yb, Er, Sm, U, Tl, Ho and Tb of the Ecker dam water (pH=5.1) exceed those of the nearby Söse Dam water (pH=6.5) by almost one order of magnitude or more. With the exception of the spring waters on gabbro (pH up to 7.7) all waters on the highly siliceous rocks (quartzite, granite and gneiss) are dominated by sulfate anions with a pH range of 4–6. The concentrations of major conservative ions show a progressive increase with decreasing catchment elevation and decreasing average precipitation. Trace elements such as Sr, Be, Zn, Cd, Ba, Y, La, lanthanides, U, Li, Ni, Al, Mn, Co, Cu, Pb, As, Sb and Tl are increased in the low acid neutralizing capacity (ANC_(aq)) spring waters. The behaviours of Sr, Be, Zn, Cd, Ba, Y, La, lanthanides and U resemble that of the major cations. The highest concentrations of Li and Ni are found on quartzite. Al, Mn, Co and Cu exhibit no clear correlation with catchment elevation and one particular bedrock. The concentrations of V and Cr show a distinct increase in high ANC_(aq) spring waters on gabbro. Pb, As, Sb and Tl are characterized by being found in relatively high concentrations on granite at higher altitudes. Pb, As and Sb are affected by contaminated soils. The extreme variability of trace element concentrations of low ANC_(aq) spring waters cannot be explained by the rock data. It is mainly controlled by the topography-dependent weathering rates of the different rock-types and the decreasing dilution with decreasing catchment elevation.     

Thermodynamic and kinetic aspects of formation of bauxites

Experiments in which cleavage nepheline samples were reacted with aqueous solutions at fixed pH's and temperature were carried out in the laboratory. The chemistry of the solution as a function of time was monitored, as well as the chemistry of the nepheline surfaces.

At 25°C, Al derived from the nepheline stays in solution due to slow precipitation kinetics of Al(OH)₃. At 60° and 80°C, precipitation of Al(OH)₃ is so rapid that Al concentration in solution is below 0.05 ppm. This indicates that precipitation kinetics favour the formation of bauxite deposits in tropical regions (i.e. T25°C), but not in temperate regions.

Precipitation products on the surface of the nepheline fragments at 60° and 80°C depend on the pH. At pH 3.0, an amorphous aluminium silicate (proto-kaolinite?) is formed. At pH>7.0, the precipitated phase contains, in addition to Al and Si, high amounts of Na and K (proto-muscovite?). The optimum pH for the formation of bauxite is in the range 5–7. These results are in agreement with thermodynamic calculations.     

Laboratory study of calcite–gypsum sludge–water interactions in a flooded tailings impoundment at the Kristineberg Zn–Cu mine,northern Sweden

Due to liming of acid mine drainage, a calcite–gypsum sludge with high concentrations of Zn (24,400 ± 6900 μg g⁻¹), Cu (2840 ± 680 μg g⁻¹) and Cd (59 ± 20 μg g⁻¹) has formed in a flooded tailings impoundment at the Kristineberg mine site. The potential metal release from the sludge during resuspension events and in a long-term perspective was investigated by performing a shake flask test and sequential extraction of the sludge. The sequentially extracted carbonate and oxide fractions together contained ⩾97% of the total amount of Cd, Co, Cu, Ni, Pb and Zn in the sludge. The association of these metals with carbonates and oxides appears to result from sorption and/or coprecipitation reactions at the surfaces of calcite and Fe, Al and Mn oxyhydroxides forming in the impoundment. If stream water is diverted into the flooded impoundment, dissolution of calcite, gypsum and presumably also Al oxyhydroxides can be expected during resuspension events. In the shake flask test (performed at a pH of 7–9), remobilisation of Zn, Cu, Cd and Co from the sludge resulted in dissolved concentrations of these metals that were significantly lower than those predicted to result from dissolution of the carbonate fraction of the sludge. This may suggest that cationic Zn, Cu, Cd and Co remobilised from dissolving calcite, gypsum and Al oxyhydroxides were readsorbed onto Fe oxyhydroxides remaining stable under oxic conditions. In a long-term perspective (≳10² a), ⩾97% of the Cd, Co, Cu, Ni, Pb and Zn content of the sludge potentially is available for release by dissolution of calcite and reductive dissolution of Fe oxyhydroxides if the sludge is subject to a soil environment with lower dissolved Ca concentrations, pH and redox than in the impoundment.     

湛江市菠萝主产区基岩-土壤-菠萝元素迁聚特征

为研究元素在基岩-土壤-作物系统的迁聚特征,选取湛江市徐闻县菠萝主产区为研究区,采集土壤和菠萝样品,结合元素迁移系数、生物富集系数评价了基岩-土壤-菠萝系统元素的分布和迁聚特征。结果表明: 研究区土壤含富磷(TP)、土壤全铁(TFe₂O₃)、Co、Ge、S、Se含量丰富,土壤全氮(TN)含量中等,有机质含量以中等—较丰富为主,土壤全钾(TK)含量缺乏。基岩风化成土过程中,土壤中Pb、Cr、TFe₂O₃、Ni相对基岩表现为富集,Al₂O₃、Cu、Zn、Co、Mn、TP、K₂O相对基岩表现为流失; 土壤中Co、Cr、Cu、Ge、Mn、Ni、Zn主要来源于磁铁矿风化蚀变,Se主要来源于黄铁矿风化蚀变。菠萝果实对Cd、Hg为微弱吸收,Cd相对其他元素更容易在菠萝果实中富集。Ge、As、Cd、Se、Ni在菠萝根部最为富集,Pb、Hg、Cr、Cu、Zn在菠萝叶片最为富集,菠萝果实对Cu、Pb、Cr、Hg的吸收存在协同作用。研究成果可为当地菠萝产业发展提供依据。     

内蒙古大沟井寒武纪黑色页岩元素地球化学特征及钒赋存形式

对内蒙古大沟井钒矿床的矿石样品进行了系统的常量和微量元素、X射线粉晶衍射以及显微能谱分析,探讨矿石中钒的赋存形式、形成环境以及保存条件等.研究结果表明,矿石样品中P2 O5含量变化范围为0.81％～6.14％,显示其磷含量普遍较高,反映地层中较为富集磷;样品烧失量的范围为7.75％～41.24％,比较大,反映云母及泥质...     

深层地下水稀土元素无机形态及其对稀土特征的影响——以皖北任楼矿煤系含水层为例

在对皖北任楼矿煤系含水层地下水常规离子和稀土元素组成分析的基础上,运用Visual Minteq软件对溶解态稀土的无机形态进行了模拟。结果表明:煤系含水层地下水分为富SO₄2-和富HCO₃-(或富CO₃2-)两类,二者pH值大致以8.20/8.36为界。富SO₄2-水具有相对富HCO₃-水偏低的稀土总量,但二者在PAAS(后太古代平均页岩)标准化图解上均表现为轻稀土亏损的型式。富SO₄2-水中稀土无机形态包括Ln3+、LnCO₃+、LnSO₄+、Ln(CO₃)₂-和Ln(SO₄)₂-(Ln代表稀土元素),但富HCO₃-水中以Ln(CO₃)₂-和LnCO₃+为主,且各形态的相对含量与pH值和元素类型(如轻、重稀土)关系密切。HCO₃-含量与地下水∑REE和/Nd_SN/Yb_SN存在明显的相关性,表明不同含量的稀土元素无机形态(尤其是Ln(CO₃)₂-)对地下水中稀土元素总量和轻重稀土分异程度存在影响。      

Abundance, Sources and Speciation of Trace Elements in Humus-Rich Streams Affected by Acid Sulphate Soils

The behaviour of trace elements (Al, As, Cd, Co, Cr,Cu, Fe, Mn, Ni, V, Zn) was studied in five humus-richstreams (dissolved organic carbon = 14–40 mg/L)impacted by acid sulphate soils developed in marinesulphide-bearing fine-grained sediments. During heavyrainfalls in autumn, on which the study focusses, themetals Al, Cd, Co, Cu, Mn, Ni and Zn are extensivelyleached from these acidic soils (pH = 2.5–4.5), whileAs, Cr, Fe and V are not leached more strongly fromthis soil type than from areas of till and peat. Aspeciation experiment, based on anion and cationexchange of the stream waters in the field, showedthat (1) the metals Al, Cd, Co, Mn, Ni and Zn aretransported in the streams mainly as inorganiccations, (2) Cu exists mainly in cationic form but isalso to a significant extent associated with dissolvedhumic substances, (3) Fe occurs mainly in the anionicfraction explained by organic coating on colloidal Feoxyhydoxides and (4) the hydrochemistry of As, Cr andV is complex as these elements may exist in severalunquantified anionic fractions and to a minor extentin cationic species/forms. Whereas the proportion ofacid sulphate soils in the catchments had a largeimpact on concentrations levels of several elements inthe stream waters, these soils did not have a largeaffect on the speciation of elements in water.     

干湿循环作用下污泥固化土三维力学特性研究

采用自主研发的新型固化剂对天津城市污泥进行固化处理,通过GCTS真三轴仪对污泥固化土进行不固结不排水试验,探讨其在干湿循环作用下的应力-应变特征和强度指标变化规律。试验结果表明:污泥固化土应力-应变曲线在初始阶段近似表现为线性关系,同等条件下,破坏应力随中主应力比b的增大而增大;相同b值下,破坏应力随干湿循环次数的增大而逐渐减小。经过干湿循环1,3,5,7,10次之后,不同围压下污泥固化土的破坏应力值均呈现下降趋势。当循环次数超过5次后,其降低幅度趋于平缓。在b值较小、循环次数小于3时,应力-应变曲线产生应变软化现象,随着围压和b值的增大表现为硬化型。污泥固化土c、φ值随干湿循环次数的增大呈现出降低趋势,并最终趋于稳定。在此基础上,对不同中主应力比条件下的c、φ值变化规律进行分析,分别建立其与干湿循环次数和中主应力比之间的关系式,并构建出能够考虑不同围压及中主应力比影响的初始弹性模量E_i和主应力差渐近值（σ₁?σ₃）_ulti预测公式。     

Acid neutralization mechanisms and metal release in mine tailings: a laboratory column experiment

Mining and milling of base metal ore deposits can result in the release of metals to the environment. When sulfide minerals contained in mine tailings are exposed to oxygen and water, they oxidize and dissolve. Two principal antagonistic geochemical processes affect the migration of dissolved metals in tailings impoundments: sulfide oxidation and acid neutralization. This study focuses on acid neutralization reactions occurring in the saturated zone of tailings impoundments. To simulate conditions prevailing in many tailings impoundments, 0.1 mol/L sulfuric acid was passed continuously through columns containing fresh, unoxidized tailings, collected at Kidd Creek metallurgical site. The results of this column experiment represent a detailed temporal observation of pH, Eh, and metal concentrations. The results are consistent with previous field observations, which suggest that a series of mineral dissolution-precipitation reactions control pH and metal mobility. Typically, the series consists of carbonate minerals, Al and Fe(III) hydroxides, and aluminosilicates. In the case of Kidd Creek tailings, the dissolution series consists of ankerite-dolomite, siderite, gibbsite, and aluminosilicates. In the column experiment, three distinct pH plateaus were observed: 5.7, 4.0, and 1.3. The releases of trace elements such as Cd, Co, Cr, Cu, Li, Ni, Pb, V, and Zn were observed to be related to the pH buffering zones. High concentrations of Zn, Ni, and Co were observed at the first pH plateau (pH 5.7), whereas Cd, Cr, Pb, As, V, and Al were released as the pH of the pore water decreased to 4.0 or less.     

Mg-Fe云母化学成分的解释和分类(Ⅰ)——基本置换和黑云母平面

中国东部花岗岩类141个Mg-Fe云母的化学成分将近90%的变化属于八面体层内的类质同象置换,置换矢量Mg ₁Fe⁺²和Fe_-3⁺²(R_Ⅵ⁺³)_-2□_Ⅵ组成了天然黑云母平面,大约80%的变化应当解释为基本置换8Mg ₁Fe⁺²+Fe_-3⁺²(R_Ⅵ⁺³)₂□_Ⅵ.这些是Mg-Fe云母在广泛的自然条件下表现出来的最主要的晶体化学关系。文中还提出了置换矢量的长度、分量和以及电价和三个参数,用以识别矿物化学成分变化的类质同象置换特征。     

洞庭湖平原土壤铅活动性影响因素研究

为了系统地探讨洞庭湖平原土壤铅(Pb)活动性特征及其影响因素,本次研究在常德市、益阳市、株洲市共采集了110件水稻根系土样品,讨论了土壤Pb活动态含量和活动系数与有机质、pH值、阳离子交换量(CEC)等土壤理化性质的相关性,并据此建立了Pb活动态含量和活动系数的预测模型。研究结果表明:土壤Pb含量、pH值、有机质含量、CEC和风化程度都是影响Pb活动态含量及活动系数的主要因素。pH值、CEC和有机质含量都会影响土壤缓冲能力,进而影响Pb的活动性。土壤Cd含量和Zn/Pb值也与Pb活动态含量有显著相关性;在不同的浓度梯度内,Cd与Pb的交互作用不同;土壤具有较高的Zn/Pb 值时,Pb活动态含量较低。采用逐步回归法建立了土壤Pb活动态含量以及活动系数的预测模型,土壤Pb活动态含量用土壤pH、Pb含量、CEC和Na₂O/K₂O值进行预测,活动态系数用pH、CEC、SiO₂/Al₂O₃值进行预测,预测效果均较好。     

Lithium in the interlayer space of synthetic trioctahedral micas

This paper gives several new and strong arguments in favour of the possibility of fixation of anhydrous lithium in the interlayer space of trioctahedral potassium micas. From the chemical viewpoint Li⁺ can replace K⁺, but is located out of the alkaline cation site; it enters pseudo-octahedral cavities limited by the triangular bases of two aluminous tetrahedra of two consecutive sheets. The solubility limit of Li⁺ in the interlayer is a function of the Al^IV content of the mica. It is given by the relation (Li/Li + K)_max = 2[(Al/Si + Al)^IV]². In both micas investigated — phlogopite, KMg₃(Si₃Al)O₁₀(OH)₂, and eastonite, K(Mg_2.5Al_1.5)(Si_2.5Al_1.5)O₁₀(OH)₂ — there is a remarkable agreement between the calculated values of the solubility limits and those measured by exchange reactions with hydrothermal solutions, at 600°C, 2 kbar. In high-Al micas, the interlayer Li content can be very important, with about one-third of K⁺ replaced by Li⁺.

The fixation of Li⁺ according to this model provokes a strong flattening of the interlayer (strong decrease of the reticular distance d₀₀₅) and a slight increase of the reticular distance d₀₆₀. Infra-red (IR) absorption spectrometry shows that vacant K⁺ sites are created when Li⁺ enters the interlayer; one observes low-frequency OH stretching bands attributed to OH dipoles lying towards these empty sites. Fixation of Li⁺ does not provoke any modification of the IR spectra in the region 1200-300 cm⁻¹, indicating that Li⁺ is really out of the sheet. For both cell dimensions and IR spectra, a comparison is made with “ordinary” lepidolites, having Li⁺ in the octahedral sheet; it provides a guide for the distinction between the two species of Li-bearing micas.     

康滇古陆东缘筇竹寺组地球化学特征及意义

云南省昭通市昭阳区锌厂沟位于康滇古陆东缘,在剖面测量及样品系统采集分析基础上,建立了该区下寒武统筇竹寺组泥页岩地球化学剖面,为该区筇竹寺组沉积环境、物源分析提供了定量的地球化学数据。研究结果显示:1）筇竹寺组物源主要来自康滇古陆中元古界东川群、会理群砂泥岩、海相玄武岩,并可能有少许同时代花岗岩,形成于康滇古陆东缘大陆坡或边缘海,自西向东呈康滇古陆—潮坪—浅水陆棚—深水陆棚—水下隆起有序变化,工区位于浅水陆棚相;2）稀土元素δCe值、δEu值及微量元素Mo、V含量、（V）_N/（V+Ni）_N比值、（Cu）_N/（Zn）_N比值反映筇竹寺组底部为深水陆棚环境,上部总体为浅水陆棚沉积环境,局部水体加深为深水陆棚沉积环境。总体上该区以浅水陆棚为优势相,并具酸性还原环境特点;3）微量元素Rb、Ba、Ga、V、Zn、Mo、Cd、Sn、Zr有明显的富集。主量元素（SiO₂）_N/（Al₂O₃）_N比值及微量元素Ba、U含量、Zn-Ni-Co三角图、U/Th比值、Co/Zn比值表明有生物或热水作用的参与。     

Oxidative dissolution of pyritic sludge from the Aznalcóllar mine (SW Spain)

As a result of the collapse of a mine tailing dam, a large extension of the Guadiamar valley was covered with a layer of pyritic sludge. Despite the removal of most of the sludge, a small amount remained in the soil, constituting a potential risk of water contamination. The kinetics of the sludge oxidation was studied by means of laboratory flow-through experiments at different pH and oxygen pressures. The sludge is composed mainly of pyrite (76%), together with quartz, gypsum, clays, and sulphides of zinc, copper, and lead. Trace elements, such as arsenic and cadmium, also constitute a potential source of pollution. The sludge is fine grained (median of 12 μm) and exhibits a large surface (BET area of 1.4±0.2 m² g⁻¹).

The dissolution rate law of sludge obtained is r=10^{−6.1(±0.3)} [O₂(aq)]^0.41(±0.04) a_H+^0.09(±0.06) g_sludge m⁻² s⁻¹ (22 °C, pH=2.5–4.7). The dissolution rate law of pyrite obtained is r=10^{−7.8(±0.3)} [O₂(aq)]^0.50(±0.04) a_H+^0.10(±0.08) mol m⁻² s⁻¹ (22 °C, pH=2.5–4.7). Under the same experimental conditions, sphalerite dissolved faster than pyrite but chalcopyrite dissolves at a rate similar to that of pyrite. No clear dependence on pH or oxygen pressure was observed. Only galena dissolution seemed to be promoted by proton activity. Arsenic and antimony were released consistently with sulphate, except at low pH conditions under which they were released faster, suggesting that additional sources other than pyrite such as arsenopyrite could be present in the sludge. Cobalt dissolved congruently with pyrite, but Tl and Cd seemed to be related to galena and sphalerite, respectively.

A mechanism for pyrite dissolution where the rate-limiting step is the surface oxidation of sulphide to sulphate after the adsorption of O₂ onto pyrite surface is proposed.     

Removal of trace metals by coprecipitation with Fe,Al and Mn from natural waters contaminated with acid mine drainage in the Ducktown Mining District,Tennessee

This study examined the sorption of trace metals to precipitates formed by neutralization of 3 natural waters contaminated with acid mine drainage (AMD) in the former Ducktown Mining District, Tennessee. The 3 water samples were strongly acidic (pH 2.2 to 3.4) but had distinctively different chemical signatures based on the mole fractions of dissolved Fe, Al and Mn. One sample was Fe-rich (Fe=87.5%, Al=11.3%, and Mn=1.3%), another was Al-rich (Al=79.4%, Mn=18.0%, and Fe=2.5%), and the other was Mn-rich (Mn=51.4%, Al=25.7%, and Fe=22.9%). In addition, these waters had high concentrations of trace metals including Zn (37,700 to 17,400 μg/l), Cu (13,000 to 270 μg/l), Co (1,500 to 520 μg/l), Ni (360 to 75 μg/l), Pb (30 to 8 μg/l), and Cd (30 to 6 μg/l). Neutralization of the AMD-contaminated waters in the laboratory caused the formation of either schwertmannite at pH<4 or ferrihydrite at pH>4. Both phases were identified by XRD analyses of precipitates from the most Fe-rich water. At higher pH values (∼5) Al-rich precipitates were formed. Manganese compounds were precipitated at pH∼8. The removal of trace metals depended on the precipitation of these compounds, which acted as sorbents. Accordingly, the pH for 50% sorption (pH₅₀) ranged from 5.6 to 7.5 for Zn, 4.6 to 6.1 for Cu, 5.4 to 7.7 for Ni, 5.9 to 7.9 for Co, 3.1 to 4.3 for Pb, and 5.5 to 7.7 for Cd. The pH dependence of sorption arose not only because of changes in the sorption coefficients of the trace metals but also because the formation and composition of the sorbent was controlled by the pH, the chemical composition of the water, and the solubilities of the oxyhydroxide-sulfate complexes of Fe, Al, and Mn.     

Flotation Separation of Trace Elements from Alkaline-Earth Matrices by Co(III) Hexamethylenedithiocarbamate before ICP-AES Determination

A method for the selective separation of Ag, Cd, Cr, Cu, Ni, Pb and Zn in traces from solutions of calcite (CaCO₃), dolomite (CaMg(CO₃)₂) and gypsum (CaSO₄.2H₂O) before their determination by inductively coupled plasma-atomic emission spectrometry (ICP-AES) is presented. The expected interferences of Ca and Mg on intensities of trace analytes were removed by collecting the elements of interest with cobalt(III) hexamethylenedithiocar-bamate, Co(HMDTC)₃. The flotation of aqueous solutions (1 l) of calcite, dolomite and gypsum was performed at pH 6.0, by 1.5 mg l⁻¹ Co and 0.6 mmol l⁻¹ HMDTC⁻. To minimise the effect of the reaction between Ca/Mg, which restrains the function of the surfactant, careful selection of the most suitable foaming reagent was necessary. The accuracy of the method was established by analysing natural alkaline-earth minerals by the standard addition method as well as using the dolomite reference materials GBW 07114 and GSJ JDo-1. The ICP-AES limits of detection following flotation on different minerals were found to be 0.080 μg g⁻¹ for Cd, 0.105 μg g⁻¹ for Ag, 0.142 μg g⁻¹ for Cu, 0.195 μg g⁻¹ for Cr, 0.212 μg g⁻¹ for Ni, 0.235 μg g⁻¹ for Zn and 0.450 μg g⁻¹ for Pb.     

土体强度参数变异水平及影响因素关联分析

利用大样本数据掌握土工参数的变异性特征,可为岩土工程可靠度分析中计算指标选取提供客观依据,提高分析结果准确性。收集了国内不同地域6条铁路勘察近千个试样的土工试验数据,经工程地质单元的聚类分析验证,建立了13组土样大样本,采用概率统计方法分析了土体强度参数c、φ的分布特征及变异系数变化规律,基于灰色理论讨论了强度参数变异水平受土体物理力学指标影响的关联性排序。研究表明:勘察工点地基土体强度参数变异系数δ_c、δ_φ均普遍处于大变异水平,且两者间呈现协同变化的正相关规律;反映土体状态特性的液性指数I_L、含水率w、压缩系数a_1-2以及天然孔隙比e与δ_c、δ_φ系数间的关联性强于体现土质自身性质的塑性指数I_P,其中,I_L是影响δ_c、δ_φ的首位因素,a_1-2和w分别为次位影响因素。得到的强度参数变异水平与影响因素关联特征,可为样本数量有限下土体强度参数的不确定性判断提供先验信息。     

Hydrogeochemical Characteristics of Acid Mine Drainage around the Abandoned Youngdong Coal Mine in Korea

Abstract: To determine the geochemical characteristics of the Imgok creek impacted by acid mine drainage (AMD) generated from the abandoned Youngdong coal mine in Korea, chemical analyses of water samples and precipitates and the geochemical modelling of the precipitates were conducted. Acid mine drainage drained from the mine adit and coal refuse piles shows a low pH, high conductivity and high concentrations of Fe, Al, SO₄ and heavy metals such as Co, Cu, Ni and Zn. In the Imgok creek, the concentrations of heavy metals and major cations besides Fe are decreased by dilution, but concentrations of Fe are decreased by the formation of precipitates as well as dilution. From the results of geochemical modelling, goethite is oversaturated, and schwertmannite is the most stable solid phase in the Imgok creek. Yellowish red Fe-precipitates collected at the Imgok creek are recognized as amorphous or poorly crystallized minerals from XRD patterns and Fe_ox/Fe_totratios, and as containing chemically bonded SO₄ and OH by an IR analysis. The mole ratios of Fe/S in these precipitates, which are determined by EPMA, are 5. 1 and 6. 1.     

淄博市区大气颗粒物重金属元素分布特征及其来源分析

为科学认识淄博市区大气颗粒物污染状况,探讨颗粒物的污染水平和元素在颗粒物中的分布与分配特征,对颗粒物中元素的来源进行分析。于2015年冬季和夏季期间分别布设45个和16个采样点采集悬浮颗粒物（TSP）、PM₁₀及PM_2.5样品,分析了颗粒物和18种元素（或化合物）的质量浓度。结果表明：1）大气颗粒物中冬季TSP、PM₁₀及PM_2.5的质量浓度均值高于夏季;PM₁₀和PM_2.5质量浓度均超过国家标准,其中冬季PM_2.5质量浓度是标准限值的1.96倍。2）不同粒径的颗粒物中元素质量分数差别显著,As、Cd、Cr、Cu、Ni、Pb、Zn等多数重金属元素主要富集在PM_2.5中,且PM_2.5约占PM₁₀的65%（冬季）和73%（夏季）。3）颗粒物PM_2.5中Al₂O₃、CaO、Fe₂O₃、K₂O、MgO等氧化物主要受土壤扬尘控制;As、Cd、Hg、Pb、Se、Zn等元素主要源于人为污染;Se的富集因子最高,反映了PM_2.5污染主要来源于燃煤;Co、Cu、Ni、Na₂O受土壤扬尘和人类活动的共同作用,而Cr具有混合污染的特点。