大宝山采矿活动对环境的重金属污染调查

调查了大宝山铁铜多金属矿床固体废弃物-水相互作用对环境的重金属污染,结果表明,矿床固体废弃物导致了水、土壤的重金属污染,污染元素主要有Cd、Cu、Pb、Zn等;重金属元素的水迁移强度由大至小顺序为Cr、Cu、Zn、Ni、Cd、As、Pb、Hg;元素的生物吸收系数由大至小顺序为Cd、Zn、Hg、Ni、Cu、Cr、As、Pb,虽然水稻糙米中的重金属含量未超过国家标准,但Cd、Cr两种元素含量已远远超出了植物中毒量的下限值.     

污泥中重金属的去除及回收试验

论述了利用离子交换技术循环使用柠檬酸去除污泥中重金属,并置换回收重金属的适宜工艺条件.经柠檬酸处理后,污泥中90%以上的重金属被去除;柠檬酸处理液中的重金属用离子交换法回收,考察了树脂种类、流速、操作方式等因素对离子交换、再生效果的影响;在适宜工艺条件下,重金属的交换率均为100%,而洗脱率均接近90%;柠檬酸及离子交换树脂循环使用,重金属也得到回收,降低了处理成本.     

环境监测中重金属污染的控制对策分析

在我国社会经济快速发展的过程中,人们对自然资源需求无度,造成生态环境破坏问题非常严重。通过环境监测可以及时分析空气中有毒有害的物质成分,并且对环境污染问题进行及时有效的解决。但是在监测的过程中所采用大量的空气试剂很容易造成环境二次污染等问题,为此必须要积极加强对环境监测中重金属污染的合理控制,对空气试剂产生的大量废弃物进行及时的回收处理,从而有效避免出现二次污染的情况,充分发挥环境监测的作用。     

农田重金属污染修复新技术展望与探索

目前,土壤重金属污染已成为全球各国共同面临的棘手问题。土壤重金属污染具有隐蔽性、滞后性、积累性、持久性等特点,已严重危害到人类的健康。本文在全面了解国内外重金属污染土壤修复研究动态的基础上,对纳米多孔磁性螯合材料用于农田重金属污染土壤修复的新技术进行展望与探索研究,为国内这一领域的工作开展提供借鉴参考。     

Magnetotactic bacteria: Characteristics and environmental applications

• Magnetotactic bacteria (MTB) synthesize magnetic nanoparticle within magnetosomes. • The morphologic and phylogenetic diversity of MTB were summarized. • Isolation and mass cultivation of MTB deserve extensive research for applications. • MTB can remove heavy metals, radionuclides, and organic pollutants from wastewater. Magnetotactic bacteria (MTB) are a group of Gram-negative prokaryotes that respond to the geomagnetic field. This unique property is attributed to the intracellular magnetosomes, which contains membrane-bound nanocrystals of magnetic iron minerals. This review summarizes the most recent advances in MTB, magnetosomes, and their potential applications especially the environmental pollutant control or remediation. The morphologic and phylogenetic diversity of MTB were first introduced, followed by a critical review of isolation and cultivation methods. Past research has devoted to optimize the factors, such as oxygen, carbon source, nitrogen source, nutrient broth, iron source, and mineral elements for the growth of MTB. Besides the applications of MTB in modern biological and medical fields, little attention was made on the environmental applications of MTB for wastewater treatment, which has been summarized in this review. For example, applications of MTB as adsorbents have resulted in a novel magnetic separation technology for removal of heavy metals or organic pollutants in wastewater. In addition, we summarized the current advance on pathogen removal and detection of endocrine disruptor which can inspire new insights toward sustainable engineering and practices. Finally, the new perspectives and possible directions for future studies are recommended, such as isolation of MTB, genetic modification of MTB for mass production and new environmental applications. The ultimate objective of this review is to promote the applications of MTB and magnetosomes in the environmental fields.     

南京市农用地土壤中重金属形态特征分析

以南京市农用地土壤为研究对象,采用顺序提取的方法对Cu、Zn、Pb、Cd做化学形态分析,了解不同元素各形态下空间赋存的含量与占比。结果表明,在农用地土壤中,上述4种金属元素所赋存的化学形态活泼性顺序为CdPbCuZn,其中Cd主要为醋酸提取态,Pb主要为可还原态,各占总量的40%以上,具有较高的生物有效性和潜在危害性;Cu与Zn主要为残渣态,占总量的60%左右,生物可利用性较低。由因子分析法可知,土壤p H值越大,Zn与Cd就越趋于向稳定的化学形态转化,土壤有机质含量越高,对Cu与Pb的络合能力就越强,可以降低其环境危害性。     

Metal accumulation and performance of nestlings of passerine bird species at an urban brownfield site

The use of passerine species as bioindicators of metal bioaccumulation is often underutilized when examining the wildlife habitat value of polluted sites. In this study we tested feathers of nestlings of two common bird species (house wren and American robin) for accumulation of Pb, Zn, As, Cr, Cu, Fe in comparison of a polluted, urban brownfield with a rural, unpolluted site. House wren nestlings at the study site accumulated significantly greater concentrations of all target metals except Zn. At the polluted site we found significant species differences of metal concentrations in feathers, with house wrens accumulating greater concentrations of Pb, Fe, and Zn but slightly lesser accumulations of Cr and Cu than American robins. Although house wren nestlings demonstrated significant accumulation of metals, these concentrations showed little effect on size metrics or fledge rates during the breeding season compared to nestlings from the control site.     

Appraisal of measurement methods, chemical composition and sources of fine atmospheric particles over six different areas of Northern Belgium

Daily and seasonal variation in the total elemental, organic carbon (OC) and elemental carbon (EC) content and mass of PM_2.5 were studied at industrial, urban, suburban and agricultural/rural areas. Continuous (optical Dustscan, standard tapered element oscillating micro-balance (TEOM), TEOM with filter dynamics measurement system), semi-continuous (Partisol filter-sampling) and non-continuous (Dekati-impactor sampling and gravimetry) methods of PM_2.5 mass monitoring were critically evaluated. The average elemental fraction accounted for 2-6% of the PM_2.5 mass measured by gravimetry. Metals, like K, Mn, Fe, Cu, Zn and Pb were strongly inter-correlated, also frequently with non-metallic elements (P, S, Cl and/or Br) and EC/OC. A high OC/EC ratio (2-9) was generally observed. The total carbon content of PM_2.5 ranged between 3 and 77% (averages: 12-32%), peaking near industrial/heavy trafficked sites. Principal component analysis identified heavy oil burning, ferrous/non-ferrous industry and vehicular emissions as the main sources of metal pollution.     

Understanding world metals prices—Returns,volatility and diversification

In recent times, the prices of internationally traded metals have reached record highs and there is considerable uncertainty regarding their future. This phenomenon is partially driven by strong demand from a small number of emerging economies, such as China and India. This paper uses a long time-series (1900–2007) on 21 metals prices to investigate their properties, and presents unique features of their volatility, including a decomposition into within- and between-group components. If most volatility is commodity-specific rather than “global”, then metals-exporting dependent economies can smooth income via diversification.     

Combining a finite mixture distribution model with indicator kriging to delineate and map the spatial patterns of soil heavy metal pollution in Chunghua County, central Taiwan

This study identifies the natural background, anthropogenic background and distribution of contamination caused by heavy metal pollutants in soil in Chunghua County of central Taiwan by using a finite mixture distribution model (FMDM). The probabilities of contaminated area distribution are mapped using single-variable indicator kriging and multiple-variable indicator kriging (MVIK) with the FMDM cut-off values and regulation thresholds for heavy metals. FMDM results indicate that Cr, Cu, Ni and Zn can be individually fitted by a mixture model representing the background and contamination distributions of the four metals in soil. The FMDM cut-off values for contamination caused by the metals are close to the regulation thresholds, except for the cut-off value of Zn. The receiver operating characteristic (ROC) curve validates that indicator kriging and MVIK with FMDM cut-off values can reliably delineate heavy metals contamination, particularly for areas lacking background information and high heavy metal concentrations in soil.