Mobility of Al, Co, Cr, Cu, Fe, Mn, Ni and V in sulphide-bearing fine-grained sediments exposed to atmospheric O2: an experimental study   总被引：1，自引：0，他引：1  

Mats Åström 《Environmental Geology》1998,36(3-4):219-226

 The major aim was to increase our knowledge on the behaviour of Al, Co, Cr, Cu, Fe, Mn, Ni and V in sulphide-bearing fine-grained sediments exposed to atmospheric oxygen. Samples of this type of sediment collected in a previous investigation at eight sites in western Finland were digested in HClO₄-HNO₃-HCl-HF at 200  °C and in HCl:HNO₃:H₂O at 95  °C (aqua regia), and subjected to extractions with ammonium acetate and hydrogen peroxide. Metals and S in the leachates were determined with ICP-AES. The results of the chemical analyses are compared with previously reported experimental data. The concentrations of Al and Fe in the sulphide-bearing fine-grained sediments are about 7% and 5%, respectively. Of the trace metals studied, Mn is most abundant followed in decreasing order by V>Cr>Ni>Cu>Co. On oxidation of the sediments, high proportions of Co, Mn and Ni, intermediate proportions of Cu but low proportions of Fe, Al, Cr and V are released. The extent of the release of a metal on oxidation is controlled either by (1) the level to which the pH of the sediments drops on oxidation (Al, Cu, Cr, V), (2) the amount of the metal associated with easily reduced phases (metal sulphides) in the sediments (Ni, Co) or (3) the sum of the amount associated with reduced phases and adsorbed on soil compounds (Mn). No control of the release of Fe on oxidation of the sediments was identified. Based on the results of the study it is argued that artificial drainage and the subsequent oxidation of sulphide-bearing sediments will result in extensive leaching of Co, Mn and Ni, moderate leaching of Cu and limited leaching of Cr and V into drainages. The major elements, Fe and Al, have the potential to be mobilised and leached in large amounts, though the proportions mobilised/leached will remain low. It is suggested that the identification of sulphide-bearing sediments with a high potential of metal release should be based on determination of metals in easily mobilised reduced compounds (dissolved e.g. in H₂O₂) and of the level to which the pH of the sediments drops on oxidation. Received: 16 October 1997 · Accepted: 9 March 1998  相似文献   

Mineral magnetic and physical properties of surficial sediments and onshore samples from the southern basin of Lake Baikal, Siberia     

J.A. Lees  R.J. Fowler  P.G. Appleby 《Journal of Paleolimnology》1998,20(2):175-186

Results of lithostratigraphic and mineral magnetic analysis of two surficial sediment cores (21 cm and 45 cm in length) collected from the Southern basin of Lake Baikal at a water depth of 1390 m, are presented. The sediments have been measured for a wide range of mineral magnetic parameters in order to assess their value in the identification of turbidite layers. Particle size and geochemical data are also presented and these explain some of the down core variations in magnetic mineralogy. It is suggested that changes in the particle size frequency distributions down core may be related to fossil diatom shells. One of the cores has been dated using ²¹⁰Pb. The sediment cores were cross-correlated using low frequency magnetic susceptibility (f) and these cores can also be correlated with a nearby core collected earlier in 1992. Changes in the magnetic parameters of lf, IRMs and HIRM₂₁₀ suggest that there are significant changes in the concentration of ferrimagnetic minerals in the sediment cores, indicating changing sediment sources and/or increasing concentrations of spheroidal carbonaceous particles and the dissolution of minerals through reduction below the oxidised layer within the sediment core.  相似文献   

Speleothems as high-resolution paleoenvironment archives: Records from northeastern China     

T. L. Ku  H. C. Li 《Journal of Earth System Science》1998,107(4):321-330

The isotopic compositions of oxygen and carbon and trace concentrations of magnesium and strontium in speleothems formed in limestone caves respond to climate changes outside the caves. Measurements of these properties on a stalagmite from Shihua Cave near Beijing, China, allowed reconstruction of the regional changes in precipitation, temperature and nature of vegetation. Over the last ∼ 500 years, there were fourteen precipitation cycles with a periodicity of 30–40 years, which may well reflect fluctuations in the strength of the East Asian summer monsoons reaching northeastern China. Relative to the mean temperature of this time interval, the period 1620–1900 AD was cold and periods 1520–1620 and 1900–1994 were warm. Over the last ∼ 3000-years, about eight wet/cool-dry/warm climatic cycles of 300–400 years duration occurred, the latest wet/cool half cycle corresponding to the Little Ice Age. The δ¹³C record registers the anthropogenic activities of fossil fuel CO₂ combustion in recent decades and regional deforestation between 13 and 16 centuries when Beijing was bustling with palatial constructions and being developed into the world’s most populated city.  相似文献   

Humic Ion-Binding Model VI: An Improved Description of the Interactions of Protons and Metal Ions with Humic Substances   总被引：1，自引：0，他引：1  

Edward Tipping 《Aquatic Geochemistry》1998,4(1):3-47

Humic Ion-Binding Model VI, a discrete site/electrostatic model of the interactions of protons and metals with fulvic and humic acids, is applied to 19 sets of published data for proton binding, and 110 sets for metal binding. Proton binding is described with a site density, two median intrinsic equilibrium constants, two parameters defining the spread of equilibrium constants around the medians, and an electrostatic constant. Intrinsic equilibrium constants for metal binding are defined by two median constants, log K_MA and log K_MB, which refer to carboxyl and weaker-acid sites respectively, together with a parameter, LK₁, defining the spreads of values around the medians. A further parameter, LK₂, takes account of small numbers of strong binding sites. By considering results from many data sets, a universal average value of LK₁ is obtained, and a correlation established between log K_MB and log K_MA. In addition, a relation between LK₂ and the equilibrium constant for metal-NH₃ complexation is tentatively suggested. As a result, metal-binding data can be fitted by the adjustment of a single parameter, log K_MA. Values of log K_MA are derived for 22 metal species. Model VI accounts for competition and ionic strength effects, and for proton-metal exchange.  相似文献   

贵金属资源的应用及开发   总被引：1，自引：1，他引：0  

唐杰  张凯 《世界地质》1998,17(4):98-102

将贵金属的应用,资源分布,生产和贵金属的分析化学结合在一起进行了综述,由于贵金属资源的短缺性及考虑可持续发展战略,特别介绍了贵金属资源的二次回收问题,并对其将来的发展作了一定的评价和展望。  相似文献   

Heavy metal release by peat erosion in the Peak District,southern Pennines,UK     

J. J. Rothwell  S. G. Robinson  M. G. Evans  J. Yang  T. E. H. Allott 《水文研究》2005,19(15):2973-2989

Upper North Grain (UNG) is a heavily eroding blanket peat catchment in the Peak District, southern Pennines, UK. Concentrations of lead in the near‐surface peat layer at UNG are in excess of 1000 mg kg⁻¹. For peatland environments, these lead concentrations are some of the highest globally. High concentrations of industrially derived, atmospherically transported magnetic spherules are also stored in the near‐surface peat layer. Samples of suspended sediment taken during a storm event that occurred on 1 November 2002 at UNG, and of the potential catchment sources for suspended sediments, were analysed for lead content and the environmental magnetic properties of anhysteretic remanent magnetization (ARM) and saturation isothermal remanent magnetization (SIRM). At the beginning of the storm event, there is a peak in both suspended sediment and associated lead concentration. SIRM/ARM values for suspended sediment samples throughout the storm reveal that the initial ‘lead flush’ is associated with a specific sediment source, namely that of organic sediment eroded from the upper peat layer. Using the magnetic ‘fingerprinting’ approach to discrimination of sediment sources, this study reveals that erosion of the upper peat layer at UNG is releasing high concentrations of industrially derived lead (and, by inference, other toxic heavy metals associated with industrial particulates) into the fluvial systems of the southern Pennines. Climate‐change scenarios for the UK, involving higher summer temperatures and stormier winters, may result in an increased flux both of sediment‐associated and dissolved heavy metals from eroding peatland catchments in the southern Pennines, adversely affecting the quality of sediment and water entering reservoirs of the region. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Preliminary comparison of trace metals in coastal aerosols between Qingdao and Liverpool     

刘昌岭  张经 《中国海洋湖沼学报》2008,26(2):203-214

Aerosol samples were collected at two coastal suburban stations, Qingdao （China） in 1995-1996 and Liverpool （U.K.） in 1995, respectively. The samples were analyzed to determine the concentrations of trace metals （Cr, Zn, Cu, Co, Ni, Pb, V, and Cd） as well as A1, Fe and Mn. Data were examined to understand the difference of trace metals in aerosols between coastal zones downwind the developing area （near the Yellow Sea） and developed region （near the Irish Sea）. The results show that most elements at Qingdao have levels 4-5 times higher than those at Liverpool, particularly for the crust-dominated elements （e.g. Al, Fe and Mn）. Moreover, the aerosol composition at Qingdao is higher in spring than in summer, underlying the influence of westerlies and local emissions in combination, whereas seasonal change of aerosol composition is not significant at Liverpool. The enrichment factors for the crustal source elements （EFcrust） at Liverpool are much higher than those at Qingdao. The contributions from the pollutant source （Rp） for some trace metals like Cu, Pb, Zn and Cd are 〉90% at Qingdao and Liverpool, suggesting overwhelming anthropogenic contributions to these metals. The contributions from crustal source （Re） for trace metals tend to increase with higher aerosol levels and Al concentration at Qingdao, indicating a good correlation between the crust-dominated component and the air mass. At Liverpool, the Rc values for trace metals are positively correlated with Al concentrations instead of with aerosol mass, suggesting that Al in aerosols represents the crustal component even though the aerosols come from different sources.  相似文献   

Heavy metals,polycyclic aromatic hydrocarbons and organochlorine pesticides in the surface sediments of mangrove swamps from coastal sites along the Leizhou Peninsula, South China     

TANG Yijie  FANG Zhanqiang  YU Shixiao 《海洋学报(英文版)》2008,27(1):42-53

Contents of heavy metals, polycyclic aromatic hydrocarbons （PA Hs）, dichlorodiphenyltrichloroethanes （DDTs） and hexachlorcy- clohexanes （HCHs） in surface sediments from mangrove areas of the Leizhou Peninsula were analyzed in July and November 2005. Risk assessment criteria applied by Long E R et al. （1995） and Long E D et al. （1995） （effects range low, ERL; effects range mean, ERM） of chemicals in sediments from the gulf or estuary were used to assess the potential ecological risks of heavy metals, PAHs, DDTs and HCHs to aquatic organisms in the studied area. The results indicated that the average contents of zinc, nickel, chromium, lead, copper, arsenic and mercury were （61.97 ± 55.87）, （59.99 ± 39.01 ）, （47.93 ± 28.37）, （26.64± 13.00） , （23.45 ± 41.96）, （9.32 ± 3.62）, （0.14 ± 0.18） mg/kg in dry weight in the sediment samples col- lected from five studied sites in the Leizhou Peninsula, respectively. Cadmium was not calculated due to its content being below the detection limit （ 〈 0.3 mg,/kg）. The average levels of Cr, Cu, Ni, Pb, Zn and Hg exceed their background values. The average contents of Ni were higher than ERM. The contents of PAHs in the sediments from the five studied sites were （79.78 ± 43.70） ng/g in dry weight, far lower than ERL（4 022 ng/g）. The contents of DDE, DDD and DDTs in the sediments from five studied sites were （2.60 ± 4.68）, （ 17.52 ± 27.25 ）, （27.78 ± 46.64） ng/g in dry weight respectively, clearly higher than ERL, and the average contents of DDT were （7.66 ± 15.93） ng/g in dry weight, much higher than ERM. HCHs could be detected in the sediments only from Gaoqiao sampling site, with the average contents （0.07 ± 0.08） ng/g in dry weight.  相似文献   

Accumulation of petroleum hydrocarbons and heavy metals in clams （Ruditapes philippinarum） in Jiaozhou Bay, China   总被引：2，自引：0，他引：2  

马海青  宋茜  王旭晨 《中国海洋湖沼学报》2009,27(4):887-897

Accumulation and distributions of aliphatic and polyaromatic hydrocarbons (PAHs) and heavy metals were measured in tissues of the clam Ruditapes philippinarum collected from 5 sites in Jiaozhou Bay, Qingdao, China. The concentrations of total aliphatic hydrocarbon and PAHs ranged from 570 to 2 574 ng/gdw (gram dry weight) and from 276 to 939 ng/gdw, in the most and least polluted sites, respectively. The bio-accumulation of hydrocarbons and PAHs in the clams appeared to be selective. Aliphatic hydrocarbons were predominantly represented by short chain (<nC₂₃) n-alkanes, suggesting that petroleum hydrocarbons were likely the major contamination source. The selective uptake of 3 and 4 ring PAHs, such as naphthalene, fluorene, phenanthrene, fluoranthene and pyrene, by the clams was probably related to the physiological and bio-kinetic processes that were energetically favorable for uptake of compounds with fewer rings. Accumulation of the metals Cd, Cu, Zn, Pb, Cr, Hg, and As in the clam tissues also showed high variability, ranging from 0.043 to 87 μg/gdw. Among the 7 detected metals, Zn, Cd, Cu, and As had a particularly high potential of accumulation in R. philippinarum. In general, a positive correlation was found between the tissue concentrations and sediment concentrations of hydrocarbons and of some metals. Our study suggests that moderate contamination with polyaromatic hydrocarbons, and low to moderate contamination with metals, currently exists for clam R. philippinarum in Jiaozhou Bay, in comparison with other regional studies. A long-term monitoring program is certainly needed for assessment of the potential ecological influence and toxicity of these contaminants of R. philippinarum in Jiaozhou Bay.  相似文献   

Early Cretaceous precious fossil-bearing beds in Weijialing－Yaolugou of Jianchang Basin , western Liaoning   总被引：1，自引：0，他引：1  

DUAN Ye  ZHANG Lijun 《世界地质(英文版)》2009,12(2):87-93

The Jianchang Basin is one of the main localities of the precious fossils of Jehol Biota in western Liaoning. The fossil-bearing horizons are mainly in the Yixian- and J iufotang formations. In the Weijialing－Yaolugou of southwest Jianchang Basin, many precious fossils have been found at Luojiagou Bed of the 2nd Member of the Yixian Formation and at Xidian Bed of the 1st member of the Jiufotang Formation. The geologic setting, sedimentary environment and paleogeography of the precious fossil-bearing beds were also studied.  相似文献