环神农架地区植烟土壤重金属评价及其富集特征

研究了环神农架地区主要植烟土壤91个耕层样品8种重金属元素Cr、Ni、Cu、Zn、As、Cd、Pb、Hg的水平,利用单冈子和内梅罗污染指数法对该区土壤重金属环境质量状况进行了评价,并探讨了该区土壤重金属的富集特征.研究结果显示:环神农架地区土壤重金属元素含量存在较大变异,以Hg和Pb变异最大,变异系数分别为60.22%和59.78%,Ni元素变异最小,变异系数为17.81%.环神农架地Ⅸ植烟土壤Cr、Cu、As、Cd、Pb、Hg含量均符合无公害生产产地标准,Ni和Zn元素分别有3个和2个样品超标,综合污染评价显示供试土壤分别有78%和22%处于清洁和尚清洁水平.以湖北省A层(0～20 cm)土壤元素背景值为基准的研究结果表明,20世纪90年代以来,环神农架地区8种重金属均存在不同程度富集,而As、Pb、Zn、Cd、Ni富集更为明显.     

Speciation and transport of heavy metals and macroelements during electroremediation

Electroremediation makes treatment of contaminated clay soils possible. The external electrical field causes several transport processes and changes in soil chemistry. This study concerns the leachability and transport of calcium, magnesium, copper, zinc, lead, nickel manganese, chromium, and iron during treatment with an electric field of soil from a chlor-alkali factory. As expected, most elements were removed from the acidic part of the soil and accumulated in the zone where pH changed from acidic to alkaline. However, acidic leaching of the soil in this zone did not mobilize the elements. Lead formed both an anionic complex which electromigration transported toward the anode as well as a cationic lead fraction which moved toward the cathode. The anionic complex could be lead sulfate. Lead from both fractions was strongly attached to the soil after treatment. The low availability of metals and macroelements after electrokinetic remediation could make electroremediation, excavation, and deposition of the accumulation zone an alternative for the treatment of contaminated soils.     

黄山地方茶中重金属浸出规律及健康风险评价

以五种黄山地方茶为研究对象,考察了浸泡次数、浸泡时间和浸泡温度对茶叶中重金属Pb、Cu、Zn、Cd和Mn浸出的影响,并对人体健康风险进行了评价。结果表明,五种茶叶中Pb和Cu含量低于国家标准,五种重金属总浸出量与浸泡次数、浸泡时间和浸泡温度均成正相关关系,弃除浸泡1 min的茶汤可除去茶叶中1.75%~28.28%的重金属,三次浸泡后五种重金属通过茶汤饮用所产生的健康风险水平大小顺序为Cd>Mn>Cu>Zn>Pb,均不会对人体健康构成明显的危害。      

四川省茶叶中重金属与矿质元素含量分布特征

目的 研究四川省茶叶中重金属与矿质元素的分布特征。方法 收集四川省的242批茶叶样品,通过电感耦合等离子体质谱法测定分析茶叶中4种重金属元素和14种矿质元素。结果 四川省242批茶叶中,重金属的含量大小表现为铬（Cr）>铅（Pb）>砷（As）>镉（Cd）,变异系数大小关系为Pb>Cr>As>Cd;矿质元素含量大小表现为锡（Sn）>钠（Na）>钼（Mo）>钒（V）>铝（Al）>铁（Fe）>钴（Co）>铜（Cu）>锰（Mn）>镍（Ni）>锌（Zn）>钙（Ca）>钾（K）>镁（Mg）,平均变异系数41.8%～57.1%;研究发现Zn、V、Ni元素是四川省242批茶叶中的特征元素,同时经矿质元素含量综合得分计算,达州、眉山、甘孜、广元、巴中、自贡、乐山地区的茶叶对矿质元素的富集能力较强。结论 本研究可作为四川省茶叶中18种元素含量的本底值参考,为相关企业、监管机构、茶叶研究者提供数据参考。     

Dust-generation characteristics of hardwoods during sanding processes

A study of the factors that influence dust-generation during the sanding process of Malaysian hardwoods was undertaken. It was found that the amount of wood removed during the sanding process predetermined dust-generation, although the wood density and abrasive grit used also played a role. Consequently, low density wood species produced higher dust-concentration due to its relative ease of sanding, and vice-versa. The results of the study suggest that minimizing dust-generation during the hardwood sanding process could be achieved by ensuring minimal amount of wood removal as well as the use of the coarsest possible abrasive grit in the process.     

Variation in some heavy metals during the production of white cheese

The lead, cadmium, arsenic and mercury contents in samples of milk, curd and white cheese taken from a production line were investigated. The lead, cadmium and arsenic levels were found to be 12.07±0.06 ng/ml , 1.82±0.01 ng/ml and 0.64±0.03 ng/ml in milk, 219.85±0.46 ng/g , 19.58±0.34 ng/g and 8.80±0.41 ng/g in cheese curd, 250.63±0.53 ng/g , 21.19±0.16 ng/g and 10.85±0.34 ng/g in fresh white cheese preripened in brine salted to 16%, and 260.25±0.51 ng/g , 22.87±0.17 ng/g and 11.35±0.29 ng/g in ripened white cheese, respectively. No detectable levels of mercury were found in any of the samples. Variation in the heavy metal contents of samples taken during the production stages was significant (p <.05). The heavy metal concentrations of the samples were compared with those obtained by other investigators in different countries.     

Impacts of traffic and rainfall characteristics on heavy metals build-up and wash-off from urban roads

An investigation into the effects of changes in urban traffic characteristics due to rapid urbanisation and the predicted changes in rainfall characteristics due to climate change on the build-up and wash-off of heavy metals was carried out in Gold Coast, Australia. The study sites encompassed three different urban land uses. Nine heavy metals commonly associated with traffic emissions were selected. The results were interpreted using multivariate data analysis and decision making tools, such as principal component analysis (PCA), fuzzy clustering (FC), PROMETHEE, and GAIA. Initial analyses established high, low, and moderate traffic scenarios as well as low, low to moderate, moderate, high, and extreme rainfall scenarios for build-up and wash-off investigations. GAIA analyses established that moderate to high traffic scenarios could affect the build-up, while moderate to high rainfall scenarios could affect the wash-off of heavy metals under changed conditions. However, in wash-off, metal concentrations in 1-75 μm fraction were found to be independent of the changes to rainfall characteristics. In build-up, high traffic activities in commercial and industrial areas influenced the accumulation of heavy metal concentrations in particulate size range from 75 - >300 μm, whereas metal concentrations in finer size range of <1-75 μm were not affected. As practical implications, solids <1 μm and organic matter from 1 - >300 μm can be targeted for removal of Ni, Cu, Pb, Cd, Cr, and Zn from build-up, while organic matter from <1 - >300 μm can be targeted for removal of Cd, Cr, Pb, and Ni from wash-off. Cu and Zn need to be removed as free ions from most fractions in wash-off.     

纳米碳对重金属镉和铜的吸附特性及对烟草吸收重金属的影响

为明确纳米碳对重金属的吸附性能,在液/液吸附体系下研究了纳米碳对镉和铜的吸附特征,并探讨了土培条件下对土壤有效态镉含量(质量分数)及烟草吸收镉的影响。结果表明,纳米碳对镉和铜的等温吸附曲线可以用Freundlich和Langmuir方程较好地拟合。纳米碳对镉和铜的吸附符合准二级动力学方程,且吸附速度较快。当溶液的初始浓度为2 000 mg/L,10 min时镉的吸附量可达到平衡吸附量的80%以上;而铜相对较快,3 min即可达到平衡吸附量的80%。随着温度的升高,纳米碳对镉和铜的吸附量降低,表明纳米碳的吸附是放热反应;随着p H值的增加,其吸附量增大。该试验条件下,随着纳米碳用量的增加,土壤有效态镉含量及烟叶中镉含量均降低。当纳米碳用量为4.0 g/盆时,效果最好。     

ICP-OES测量纺织品重金属含量的不确定度评定

采用ICP-OES法测定纺织品中的可萃取重金属铬、铜、镍的残留量,并评定测量结果的不确定度.结果表明,铬、铜、镍的扩展不确定度(k=2)分别为0.052、0.10、0.070mg/kg,工作曲线的拟合和测试重复性对测试结果的影响最大.     

静电纺丝纳米纤维膜基光化学传感器的制备及其在重金属检测中的应用进展

化学传感器特别是光化学传感器已经被广泛研究,并应用于检测目标物如食品中的重金属。静电纺丝纳米纤维膜由于具有高比表面积、高孔隙率、可控性良好和易功能化等特点,可以被用来固定传感器以提高其灵敏度。本文主要综述静电纺丝纳米纤维膜基光化学传感器的制备及其在重金属离子检测中的应用进展。首先,简单介绍光化学传感器及静电纺丝纳米纤维膜基光化学传感器,随后根据其制备方法的差异分为高分子聚合物化学修饰法、高分子聚合物物理共混法、纳米纤维化学修饰方法和纳米纤维物理吸附方法4类,并分别综述其制备得到的静电纺丝纳米纤维膜基光化学传感器应用于重金属检测的进展,这4类方法各有优势,都具有较好的应用前景。本文将为静电纺丝纳米纤维膜基光化学传感器用于目标物的检测提供指导。     

Binding of heavy metals to pomace fibers

This study demonstrates that the dietary fibers of pomace, a waste product from fruit pressing, have the potential for binding heavy metal ions. The quantity of metal ions bound varies from one fiber component to another. As it can be inferred from the results of the study, pectin was characterised by a particularly high capacity for metal ion binding. The hemicellulose fraction ranked second with respect to metal ion binding capacity. Binding of heavy metals to lignin was found to be generally poor.     

Fractional factorial design to investigate the influence of heavy metals and anions on acid neutralization behavior of cement-based products

A major concern of cement-based solidification/stabilization of hazardous wastes is the interaction of waste contaminants on cement properties. Literature contains many examples of studies on the interference of individual contaminants on cement properties. Conversely, little information is available on how the interactions between contaminants affectthe properties of cement/waste systems. This paper provides a discussion on the interference mechanisms exerted by seven contaminants, five heavy metals and two anions, on cement hydration. The seven contaminants were selected on the basis of the typical composition of municipal solid waste incineration (MSWI) fly ash. Spiking experiments using pure compounds were performed according to a 2IV(7-3) fractional factorial design to simulate addition of MSWI fly ash to ordinary Portland cement. The acid neutralization behavior of the laboratory cement-contaminant mixtures was studied to detect the presence of solid phases responsible for the buffering capacity of the solid matrix. The results from the experimental work showed that Zn, Cl-, and SO4(2-) were the major factors influencing, occasionally in combination with other contaminants, strength and acid neutralization capacity of the cementitious products. The release of Cd, Cr, Cu, and Pb in the eluates as a function of pH also suggested possible chemical immobilization mechanisms of such metals within the hardened matrix.     

重金属复合污染对茶叶重金属、主要生化成分含量及冲泡茶汤浸出率的影响研究

通过土壤盆栽实验,研究四种重金属As、Pb、Cr、Cd复合污染对茶叶重金属含量及主要生化成分含量的影响,同时研究了不同冲泡次数下茶汤中四种重金属的浸出率。结果表明:复合污染条件下,茶叶中重金属积累量显著高于对照,其高低顺序为Pb>Cr>Cd>As,其中,Cd在盆栽土壤中的添加量低于As,但在茶叶中的积累量高于Cd,表明Cd在茶树体内的迁移率高于As。复合污染茶叶中的氨基酸和咖啡碱含量均低于对照,酚氨比值高于对照,从而降低了茶叶品质。四种重金属元素在茶汤中的浸出量均随着冲泡次数的增加而减少,Cd、Cr、Pb和As的总浸出率分别为:18.0%~35.7%、14.8%~26.8%、15.4%~31.9%和13.7%~22.1%,Pb和Cd的浸出率大于Cr和As;四种重金属元素之间的络合作用,会影响重金属在茶叶中的累积量和茶汤中的浸出量。      

重金属吸附降减研究进展

重金属的检测一直以来都是人们比较关注的热点问题,重金属离子是造成水污染的重要原因.重金属离子可以进入地下水,危害居民用水;也会被粮食作物吸收,造成粮食污染;同时也会产生生物富集,最终对人体造成影响.本文描述了重金属污染水体、粮食以及食品的现状,并详细介绍了利用各类吸附剂去除重金属离子的方法,为重金属的吸附降减提供了较大...     

微波条件下陶瓷食品接触材料中有害重金属迁移行为的研究

目的 研究微波条件下陶瓷食品接触材料中有害重金属的迁移行为。方法 向陶瓷餐具中装入乙酸溶液, 进行常规处理和微波加热处理, 最后用火焰原子吸收分光光度计检测, 研究微波功率、加热时间和迁移液pH值对陶瓷餐具中铅、镉向乙酸溶液迁移的影响, 并将该方式与常规方式作对比。结果 铅、镉的迁移量随微波功率和加热时间的增加而增大, 并基本在加热15 min后达到迁移平衡; 微波功率不但影响铅、镉的迁移速度, 还影响其达到迁移平衡时的浓度; 铅、镉的迁移量随迁移液pH值的降低而增大。结论 通过短时间的微波加热, 即可使铅、镉的迁移量达到甚至显著超出(22?2)℃温度下浸泡24 h?20 min的迁移量。     

Contents of heavy metals in tree components of economical important species in relation to their residual utilisation

An 7 forstlich genutzten Standortsgruppen mit Kiefern- Fichten-, Eichen- oder Buchenbestockung wurden die Schwermetallgehalte ermittelt. Die Gehalte unterschieden sich je nach Baumart, Baumkompartiment und Standort z.T. erheblich. Bei den Schwermetallen hing die Höhe der Gehalte weniger von der Baumart ab, hier hatte die Belastungssituation des Standortes den stärksten Effekt auf die Elementgehalte. So wiesen beispielsweise nahezu alle Biomassesortimente aus Bergwerks- oder Hüttenregionen deutlich erhöhte Schwermetallgehalte auf, die die Grenzwerte zahlreicher Verordnungen übertreten und die Verwertung verschiedener Biomassesortimente für einzelne Nutzungen einschränken oder verhindern können. Dagegen können die Schwermetallgehalte von Biomassesortimenten gering belasteter Standorte i.d.R. als unbedenklich gelten     

Behaviour of tocopherols,heavy metals and stability of some vegetable oils from Egypt and Iraq during refining

Samples of crude, neutralized; bleached and deodorized cotton seed oil (Egypt), safflower oil (Iraq) and sunflower oil (Iraq) were analyzed for their total tocopherol and their contents of iron and copper, The stability of oils under investigation was measured by the Active Oxygen Method. The crude oils investigated contained from 1.22 to 1.87 ppm of iron and from 0.083 to 0.956 ppm of copper. These values for completely refined oils used were found to range from 0.626 to 1.01 ppm for iron and from 0.051 to 0.576 ppm for copper. The total tocopherol decreased from a range of 77.8 to 113 mg/100 g oils in crude oils to a range of 62.8 to 91.3 mg/100 g oil when the crude oils were completely refined. Studies on oils differing in the degree of refining used in this work evidence that neutralization and bleaching cause great decrease in total tocopherol, iron and copper. Meanwhile, deodorization had no pronounced effect on iron and copper, whereas its effect on total tocopherol was slight. The stability of the vegetable oils investigated decreased markedly during refining.     

Contents of heavy metals in tree components of economical important species in relation to their residual utilisation

Zusammenfassung An 7 forstlich genutzten Standortsgruppen mit Kiefern- Fichten-, Eichen- oder Buchenbestockung wurden die Schwermetallgehalte ermittelt. Die Gehalte unterschieden sich je nach Baumart, Baumkompartiment und Standort z.T. erheblich. Bei den Schwermetallen hing die Höhe der Gehalte weniger von der Baumart ab, hier hatte die Belastungssituation des Standortes den stärksten Effekt auf die Elementgehalte. So wiesen beispielsweise nahezu alle Biomassesortimente aus Bergwerks- oder Hüttenregionen deutlich erhöhte Schwermetallgehalte auf, die die Grenzwerte zahlreicher Verordnungen übertreten und die Verwertung verschiedener Biomassesortimente für einzelne Nutzungen einschränken oder verhindern können. Dagegen können die Schwermetallgehalte von Biomassesortimenten gering belasteter Standorte i.d.R. als unbedenklich gelten

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Contents of heavy metals in tree components of economical important species in relation to their residual utilisation

At seven forest site classes with pine, spruce, oak or beech stands the heavy metal contents of the trees were determined. The element contents differed substantially among tree species, tree compartments and forest sites. The amount of heavy metal content depended very little on tree species but mostly on the degree of pollutant inputs. For example, all tree components had high levels of heavy metals when grown on mine sits (open pits) and on close to ore treated areas. Biomass from some of these areas may exceed the limit of allowed values by several folds and thereby may not be allowed to be used for specific purposes. Heavy metal contents of biomass components from unpolluted areas may be low providing no constrain to their use.