基于形态学分析典型废弃选矿地块土壤重金属污染特征及生态风险评价

以南方某铅锌选矿厂为研究对象,分析场地内及周边土壤重金属的含量及赋存形态,并运用次生相与原生相分布比值法（RSP）评价污染程度和生态风险。结果表明,表层土壤Cd、Pb、Zn、Mn和Cu的含量明显高于深层土壤及对照点土壤。Cd的活性形态占比远高于其他重金属,以离子交换态和碳酸盐结合态为主;大部分表层土壤中Pb和Zn的活性态含量占比高于深层土壤,Cd、Pb、Zn存在淋溶释放风险,说明铅锌选矿活动对研究区土壤重金属污染影响较大。RSP评价结果显示Cd污染风险最高,达重度污染;其次为Pb;Mn、Zn和Cu大部分为中、轻污染,部分达重污染;Cr为未污染。     

某燃煤电厂废弃灰场土壤中重金属污染评价研究

对某燃煤电厂废弃灰场土壤中的Cr、Hg、As、Cu、Pb、Cd、Zn、Ni等重金属进行测定分析,并以国家二级质量标准为评价标准来评价其环境质量状况。结果表明:该灰场土壤中Hg、Pb、Zn为非污染水平,As为轻污染水平,Cr为中污染水平,Cu、Cd、Ni为重污染水平,该地块综合污染指数为24.69,达到重污染程度。     

菜子湖退耕还湿土壤重金属含量及源解析

以安庆市菜子湖8个村庄稻田土壤为研究对象,测定土壤Hg、As、Cr、Cd、Zn、Cu和Pb的含量,采用单因子污染指数法和内梅罗综合污染指数法评价退耕还湿地区土壤的污染状况,结合PMF模型解析重金属的来源.研究表明,菜子湖周边稻田土壤的重金属受人为影响较大.     

原子吸收光谱法测定土壤重金属含量实验

采用微波消解前处理,应用原子吸收光谱法对广州市芳村城郊某蔬菜种植基地土壤中Zn,Cr,Cu,Pb,Cd 5种重金属元素含量进行测定。对照《土壤环境质量标准》(GB15618-1995),结果表明:蔬菜种植地的土壤中以上5种重金属元素均为达标,该基地的土壤受污染程度较少,适合种植蔬菜。     

鄱阳湖重要支流重金属污染特征及环境风险

为探明鄱阳湖重要支流表层水重金属污染水平,对其表层水中6种重金属(Pb、Cu、As、Cr、Zn与Hg)的含量及空间分布进行了研究,采用单因子指数法和内梅罗污染指数法对其重金属污染程度进行评价,并利用主成分分析法对重金属污染进行了来源分析.结果 表明:研究区域表层水中Pb、Cu、As、Cr、Zn的平均含量分别为3.579...     

某铀矿山尾矿坝周边水土的重金属迁移规律研究

对某铀矿山尾矿坝周边不同水平距离的水体和土壤削而的pH值及重金属元素Cu,Ni,Cd,Pb,Zn进行测试分析,结果表明:pH值越低就越能促进重金属溶出,向活性形态转化;重金属污染与水平距离成反比,污染进程南近及远;与垂直深度成正比,有累积沉淀现象.     

城市生活垃圾中再生PVC富氧燃烧重金属迁移特性分析

文章采用化学热力平衡计算方法,研究富氧燃烧气氛下,再生PVC中重金属(Zn,Pb,Cd,Cr,Cu和Ni)的迁移特性,并利用高温管式炉进行实验验证。研究结果表明:燃烧温度对重金属的迁移有显著影响,高温条件下,Cl易于与重金属Zn,Pb生成易挥发的气体;燃烧温度为1 000℃时,20%O2/80%N2与20%O2/80%CO2气氛基本不影响重金属Zn,Pb和Cd的迁移,而在20%O2/80%CO2气氛下,挥发性较弱的重金属Cr,Cu和Ni在底灰中的富集程度更大。燃烧温度为1 000℃时,随着O2浓度的增加,富氧燃烧气氛能够抑制重金属的挥发。     

广州市生活垃圾典型重金属污染及生态风险评价

以广州市的生活垃圾为研究对象,分析了22个生活垃圾样品的干基组分及典型重金属Hg、Cd、Pb、Cr的含量,采用污染指数法和潜在生态风险指数法进行了污染状况与潜在生态风险评价,并用皮尔森相关分析探讨了生活垃圾中Hg、Cd、Pb、Cr的可能来源。结果表明：（1）广州市生活垃圾中Hg、Cd、Pb和Cr浓度的平均值分别为0.435 mg/kg、1.487 mg/kg、71.865 mg/kg和136.088 mg/kg;Cd的污染最严重,Hg次之,Pb和Cr的污染程度较低,点位超标率分别为40.9%、22.7%、4.5%和18.1%;大部分生活垃圾样品出现了多金属复合污染,点位超标率为63.6%。（2）Cd的潜在生态风险最高,Hg次之,Pb和Cr无潜在生态风险;重金属污染物综合潜在生态风险指数的点位超标率为45.5%,部分样品出现高的潜在生态风险;（3）Cd和Pb可能主要来源于生活垃圾中的金属成份;Hg和Cr可能分别主要来源于生活垃圾中的白塑料成分和纸类成分。     

无烟煤燃烧中的重金属排放及分布特性

为得到无烟煤燃烧中的重金属排放及分布特性,采用3.5 MW燃烧实验台进行中试实验,对无烟煤燃烧过程中的Pb、Cd、Cu、Zn、Ni和Cr等6种重金属的排放及分布特性进行了测试。实验结果表明:6种元素在飞灰中的质量分数均高于底渣,且富集于超细颗粒中,富集程度的顺序为:Pb,CdCu,ZnNi,Cr。其中,Pb和Cd在粒径约为1μm的飞灰中富集因子达到17~22。在燃烧产物中,重金属大部分分布在飞灰中,底渣和烟气中的比例很低。其中,Cd、Cu、Ni等元素全部分布在飞灰和底渣中,而Pb、Zn和Cr则少量分布在烟气中,以气态形式存在,Pb的质量分数最高、达到13.4%。     

种植区土壤重金属富集状况及生态风险评估

为调查种植区土壤重金属富集情况,采集该区域150份土壤样品,采用微波消解-ICP-MS法测定样品中Cd、Pb、As、Cr、Ni等5种重金属含量,并结合地累积指数法、污染负荷指数评价法和生态风险评价法对该区域的重金属污染情况进行评估。结果表明：该种植区的土壤含量均值未超过相关标准风险筛选值,而Cd、Pb、As、Cr、Ni等重金属含量均值分别为该区域的土壤背景值的1.3、0.8、0.98、1.36、0.87倍;各重金属地积累指数均值I_geo大小排序Cr>Cd>As>Ni>Pb;选用污染负荷指数(I_PL)来评价,150份土壤样品中强污染和中度污染样品数为4和18个,占比分别为2.7%和12%,表明该区域重金属污染差异性较大,小部分区域存在强污染,而大部分区域处于无污染状况。此外,采用生态风险指数评价各研究区域中5种重金属的综合潜在生态风险指数范围为0.16～316,潜在生态风险指数IR为3.304,其中各重金属对生态风险影响的大小排序为Cd>As>Ni>Cr>Pb,表明该区域主要重金属生态污染贡献者为...     

不同形态硫对城市生活垃圾热过程中重金属迁移特性的影响

采用管式实验炉研究了不同形态硫化物对城市生活垃圾中Cd、Cu、Cr、Pb、Ni、Zn六种元素在热过程中的迁移特性的影响,使用原子吸收光谱仪和扫描电子显微镜等仪器对重金属浓度、灰渣表面形貌等进行了分析。结果表明,在热过程中,无机硫相对于有机硫能更有效地将重金属固定在底渣中。含硫化合物的存在可以减少Cd、Cu、Pb在热过程中的挥发;其中无机硫可以减少Cr、Ni的挥发,而有机硫则会增大Cr、Ni的挥发。但在还原性气氛中,含硫化合物的存在会增大重金属的挥发。     

Beneficial effects of biochar application to contaminated soils on the bioavailability of Cd,Pb and Zn and the biomass production of rapeseed (Brassica napus L.)

Phytoremediation of soils contaminated by heavy metals was tested by liming (CaCO₃) or adding biochar (1%, 5% and 10%, mass fraction) and by growing rapeseed (Brassica napus L.), a common bioenergy crop. Bioavailable metal concentrations (0.01 mol L⁻¹ CaCl₂ extraction) decreased with increasing concentrations of biochar amendment. The reduction reached 71%, 87% and 92% for Cd, Zn and Pb respectively in the presence of 10% biochar. Twelve weeks after sowing, all plants cultivated on the untreated soil and on the soil amended by biochar at 1% had died, while the plants grew normally on the soil that had the other treatments. Compared to liming, treatment with 10% biochar proved equally efficient in reducing metal concentrations in shoots but the biomass production tripled as a result of the soil fertility improvement. Thus, in addition to C sequestration, the incorporation of biochar into metal-contaminated soils could make it possible to cultivate bioenergy crops without encroaching on agricultural lands. Although additional investigations are needed, we suggest that the harvested biomass might in turn be used as feedstock for pyrolysis to produce both bioenergy and new biochar, which could contribute further to the reduction of CO₂ emission.     

基于EK-PRB修复镉污染土壤的微生物优化技术

采用电动-可渗透反应墙(EK-PRB)联合微生物优化技术,研究其对Cd污染土壤修复效果的影响。利用固定化微生物技术,制备粉煤灰-酵母菌小球、壳聚糖-酵母菌小球和生物炭-酵母菌小球,并对比制备的PRB小球和单一的PRB材料(粉煤灰、生物炭、壳聚糖)对Cd去除效果的影响。结果表明,相对于单一的PRB材料,PRB小球可增加土壤中的电流和电导率,对Cd的去除率更高,但是对p H影响较小。通过对PRB材料进行表征分析,证实了其对Cd去除效果有一定影响。考虑到经济成本与修复效果,选择电压梯度为2.5 V·cm^-1,PRB材料为粉煤灰-酵母菌小球去除Cd,去除率可达53.70%。研究结果证实了固定化微生物结合EK-PRB技术的可行性以及修复优势。     

Emission of trace toxic metals during pulverized fuel combustion of Czech coals

A study of the trace elements emission (As, Se, Cd, Co, Cr, Cu, Zn, Hg, Tl, Pb, Ni, Sn, Sb, V, Mn and Fe) from pulverized coal combustion has been made at six heating and power stations situated in the Czech Republic. The amount of chlorine in coal has considerable influence on volatilization of some elements such as Zn, Cu, Pb, Hg and Tl, which is explained by the formation of thermodynamically stable compounds of these elements with chlorine. Generally, the affinities for Cl follows the order Tl > Cu > Zn > Pb > Co > Mn > Sn > Hg. The experimental data indicates enrichment of some of the trace toxic elements in the emissions (Cu, Zn, As, Se, Cd, Sn, Sb, Hg and Pb) and good agreement was obtained by thermodynamic equilibrium calculations with a few exceptions. In the case of Fe, Mn, Co, Cr and Sn calculated values are overestimated in the bottom ash and there are zero predicted amounts of these elements in the fly ash. In comparison, the results from experiments show up to 80% of these elements retained in fly ash. This implies that there exist additional steps leading to the enrichment by Fe, Mn, Co, Cr and Sn of small particles. Such mechanisms could include the ejection during devolatilization of small inorganic particles from the coal of bottom ash particles, or disintegration of the char containing these metals to small particles of fly ash. On the other hand, there are slightly overestimated or similar values of relative enrichment factors for As, V, Cu, Cd, Sb, Tl and Pb in the fly ashes and zero predicted values for bottom ashes. Our experimental results show about 5% or less of these elements are retained in bottom ashes, so they probably remain in the bottom ash inside unburned parts of coal. Copyright © 2003 John Wiley & Sons, Ltd.     

竹园污泥焚烧污染物排放特性的试验研究

选取上海竹园污泥,将原始污泥样品分为全干污泥、均匀干化污泥(含水率10%)和干湿混合污泥(含水率20%,干湿污泥质量比例为10∶3)三种样品,分别送入小型流化床焚烧炉中焚烧。试验研究了全干污泥在750℃、850℃、950℃三个工况下的燃烧特性,并研究了均匀干化污泥和干湿混合污泥在850℃工况下的燃烧特性。研究发现,上海竹园污泥在小型流化床焚烧炉中燃烧时,排放的主要常规污染物包括CO、SO2、NOx、HCl等以及二噁英和Cd、Hg、Pb等重金属。不同燃烧温度和含水率对污染物的排放有一定影响,提高燃烧温度,CO、SO2、NOx、HCl等的排放基本呈现出下降趋势,而烟气中Pb的排放随着温度上升而升高,相同燃烧温度下含水率升高能降低二噁英的排放总量,随着含水率的提高飞灰中重金属含量有所降低,而底渣中重金属含量呈上升趋势。     

空煤比对煤气化过程中痕量元素迁移规律的影响

采用氢化物发生器和原子荧光光谱法联用(HG-AFS)和电感耦合等离子发射光谱法(ICP-AES),测定了常压流化床煤气化产物中As、Cd、Co、Cr、Cu、Mn、Mg、Ni、Hg、Pb、V、Se、Sr、Zn 14种痕量元素含量,分析了空煤比对痕量元素在气化产物中迁移规律的影响。结果表明：在旋风高温焦中,CA、Ni富集,As、Co、Cu、V、Se、Hg耗散;空煤比对Mn、Sr、Hg、Se、As影响不大;随着空煤比增加,Pb、Zn、Cu、Co、Ni的相时富集系数(REs)略微增加,Cd、Mg的REs减少;V、Cr在低空煤比条件下有较高的REs。在布袋低温焦中,Cd、As、Cu、Cr、Ni、Pb、Zn富集,Co、V、Se、Hg耗散;随着空煤比增加,Pb、Cu、Ni的REs增加;Cd、As、Cr、Se的REs减少。底渣中的Mn和Sr相对于高、低温焦而言有轻微的富集。随着空煤比增加,Cu、Zn在煤气中含量增加,Cr、Co、As、Hg在煤气中含量减小。     

苏州河重金属污染特征及风险评价

沿苏州河水流方向设置 13个采样点进行3次采样,分析苏州河中As、Cd、Cr、Cu、Pb、Zn的分布,采用主成因分析和冗余分析,评价了苏州河水相及沉积相中微生物的稳定性以及重金属对微生物的影响。通过计算健康风险指数、内罗梅指数、地累积指数和重金属分配系数,评价了地表水中重金属对暴露人群存在的风险以及流域的生态危害。结果表明,水相中主要为Zn、Pb、Cu,沉积相中Zn质量浓度最高;研究流域的物种丰富度变化甚微;As和Cr对成人和儿童均存在不同程度的致癌风险,Cd的潜在生态危害最大。     

Distributions of environmentally hazardous elements in the Tertiary oil shale deposits from NW Anatolia,Turkey: A statistical analysis

The environmentally hazardous element concentrations (As, Cd, Cr, Cu, Hg, Mn, Pb, S, and Zn) and element–organic matter relations of the oil shale deposits in six different fields in NW Anatolia, Turkey, were investigated and the characteristics of fields were compared. The enrichment factor (EF) for most of the trace elements in the studied oil shales generally show enrichment patterns for all the fields. Only Cr, Hg, and Pb for oil shale samples from the Bahçecik field samples and Hg for oil shale samples from the Gölpazar? field samples are depleted. Arsenic in the Bahçecik field samples and Hg in the Himmeto?lu field samples are neither depleted nor enriched. The lowest and highest element enrichments in these fields are determined to be Hg and S, respectively. In general, all elements have high concentrations in the Beypazar? and Seyitömer fields and low concentrations in the Himmeto?lu, Bahçecik, and Gölpazar? (except for As) fields. A positive correlation at significance level of p ≤ 0.05 was observed for total organic carbon content with Cd in four of the fields, with Cu and S in two fields and with Cr, Mn, and Zn in only one field.     

Use of biofuel ashes for fertilisation of Betula pendula seedlings on nutrient-poor peat soil

Short-term effects of different doses (0.25; 0.5 and 1.0 kg m^?2) of wood ash (WA), peat ash (PA) and their mixture (MA) applied to peat substrate on the mineral composition and growth of seedlings of Betula pendula were investigated. The experiments were conducted with 1-year-old seedlings planted in vegetation pots. The pH of the substrate was increased by 0.4–0.9 units during the vegetation period compared to the control. The peat substrate was poor in nutrients, except N. The substrate treated with WA had higher concentrations of K, Mg, Mn, Fe, P, Zn, Cr and Pb, but a lower N concentration compared to the control. The substrate treated with PA had higher concentrations of Ca, Mg, N and P. The concentrations in the MA treatment were intermediate between WA and PA. The ashes increased K and lowered the concentration of Ca. A decrease in N in seedlings was found under the influence of WA and MA. An increase in K and P was found in all compartments of seedlings, while the concentrations of Ca, Mg, Cu, Zn, Cd and Cr in seedlings were affected irregularly depending on types and doses of ashes used. The uptake of Cd, Cr and Pb did not reach phytotoxic levels; however, increased concentrations of Cd and Pb were found in roots. A positive influence of ash application on growth was found. The heights and root collar diameters of all ash-fertilised treatments exceeded those of the control seedlings in most cases.