桓仁—宽甸地区金、有色金属成矿规律     

王文清  罗守文  邵会文 《国土资源》1993,(1)

桓仁—宽甸金、有色金属矿比集中区是华北地台北缘太平洋成矿带的重要成矿区。通过区域成矿地质背景和控矿因素的分析,划分了六种区域成矿类型及两大成矿系列,建立了区域多元成矿模式。沉积变质改造型铅锌、金、铜矿产受辽吉古裂谷含矿岩系中的特定层位控制,成矿物质来源于海底火山作用。中生代有色金属矿产受燕山晚期不同阶段特定岩性控制,第一阶段受张剪性断裂控制的中性、中酸性侵入岩与铜(铁)、金关系密切;第二阶段的中酸性脉岩控制部分铅锌、铜矿床;第三阶段的中酸性浅成、超浅成侵入体与铝、铅锌、铜矿有关。中寒武世地层可提供部分矿质,并成为接触交代型矿床的最佳赋矿层位。  相似文献   

Sea-surface microlayer metals enrichments in an urban and rural bay     

J.T. Hardy  C.W. Apts  E.A. Crecelius  N.S. Bloom 《Estuarine, Coastal and Shelf Science》1985,20(3):299-312

The sea-surface microlayer is an important interface between the atmosphere and ocean and a collection point for many anthropogenic materials including potentially toxic metals. We developed a glass plate sampler to collect the upper 30 to 55 micrometers of the sea surface. Samples of the microlayer and subsurface bulk water from an urban and rural bay were analysed for concentrations of Pb, Zn, Cu, Cd and Fe. Metal concentrations in both the microlayer and bulk water were generally 2 to 15 times greater in the urban than in the rural bay. Concentrations of metals in the microlayer of both bays averaged 6 to 65 times greater than those in the bulk water. In the urban bay, microlayer concentrations of Pb, Zn and Cu from 10 to > 100 μg 1^?1 were common. Measured microlayer metals concentrations agree well with those predicted from atmospheric deposition rates using a previously derived empirical model developed from laboratory microcosm studies. Further work will be required to determine whether or not these high microlayer metal concentrations contain significant biologically available fractions which could impact fisheries recruitment of larval icthyoneuston.  相似文献   

Global trace metal cycles and predictions     

Fred T. Mackenzie  Ronald J. Lantzy  Virginia Paterson 《Mathematical Geology》1979,11(2):99-142

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南极普里兹湾表层海水中铜、镉、锌的分布   总被引：4，自引：0，他引：4       下载免费PDF全文

孙维萍  扈传昱  薛斌  潘建明 《极地研究》2009,21(1):25-32

利用中国第24次南极考察获得的水样,研究了普里兹湾表层海水中痕量元素铜、镉、锌的含量及其分布。原子吸收分光光度法(AAS)测得普里兹湾铜、镉、锌的浓度范围分别为0·36-2.86、0.020-0.594、2.9-20.0μg·dm-3,平均值分别为1.15、0.143、11.2μg·dm-3。发现普里兹湾表层海水中铜、镉、锌的含量与南印度洋、南极海洋气溶胶及LarsemannHills湖泊群水体中的含量近似。研究表明,表层海水中铜、镉的含量及分布受悬浮颗粒物、初级生产力及盐度等的影响,锌可能受到了一定程度的人类活动的影响。  相似文献   

Assessment of heavy metal contamination of roadside soils in Southwest China   总被引：4，自引：1，他引：3  

Junhong Bai  Baoshan Cui  Qinggai Wang  Haifeng Gao  Qiuyi Ding 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(3):341-347

Topsoil (0–20 cm) samples were collected from the edge of roads to the locations about 200 m off the roads along the four roads with different transportation periods in October 2005. Total concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn were determined using the inductively coupled plasma atomic absorption spectrometry in order to assess and compare road transportation pollution. Results showed that with the exception of As, Cu and Pb, the average concentrations of heavy metals were generally, higher than the regional elemental background values. Most soil samples were moderately or highly polluted by Cd or Ni, but the contamination index (P _i ) values for As, Pb and Zn were lower than other heavy metals in all sites. Among the four roads, heavy metal pollution was heavier for Dali Road due to longer transportation periods, while low or no contamination could be observed for the other roads. However, the integrated contamination index (P _c ) values showed a generally low contamination or no contamination level for all soil samples in this region, followed by the order of Dali Road > Dabao Highway > Road 320 > Sixiao Highway. The same pollution source of these heavy metals was found using factor analysis.  相似文献   

Channel processes as a factor controlling accumulation of heavy metals in river bottom sediments: consequences for pollution monitoring (Upper Silesia, Poland)     

Dariusz Ciszewski 《Environmental Geology》1998,36(1-2):45-54

 An evaluation of the influence of channel processes (erosion, accumulation, processing of channel sediments) on the dispersal of heavy metals in bottom sediments was carried out in the channels of the Sztoła and Biała Przemsza rivers in Upper Silesia, Poland. These rivers receive waters from a Zn and Pb mine. Mine waters transport a large amount of fine-grained sediments contaminated with heavy metals. The polluted material is accumulated in these stream courses and mixed with nearly homogeneous sandy sediment derived from erosion of the river banks and bed. Because these alluvia are easily set in motion, the distribution of heavy metal concentration in the channel in fraction <1 mm reflects differences in physical processes of sedimentation in its cross-section. The minimal values in active channel and maximal in the near-bank zone are typical for those channel sections where heavy metals, present in a solid state, are transported as a suspended load (normally the largest part of a polluted river course). In short sections heavy metals associated with the grains of a large mass which has accumulated in the active channel are transported as a bed load and the typical distribution pattern is reversed (in fractions both <1 mm and <0.063 mm). Such regularities can be disturbed in localities where strong, turbulent flow or frequent eddying occur and Mn oxides and hydrooxides and associated elements precipitate. The smallest variation in heavy metal concentration in the homogenous, fine-grained bank sediments which are trapped by plants below water level is a feature which recommends these localities as being the most suitable for monitoring of river pollution. Received: 11 November 1997 · Accepted: 12 March 1998  相似文献   

中国北方某城市近郊土壤中重金属污染现状及潜在危害   总被引：4，自引：0，他引：4  

赵传冬  成杭新  庄广民  刘应汉  王晓丽 《物探与化探》2006,30(4):344-347,353

通过中国北方某城市近郊土壤环境质量的系统调查发现,本区土壤中重金属污染物的化学组成主要为Hg、Cu、Pb、Zn、Se、Cd等;该城近郊土壤的重金属污染是一种典型的大面积、低含量的散漫型污染,局部存在着一些高含量的热点污染。污染物存在形式的研究显示,本区土壤中很有可能存在着潜在的重金属"化学定时炸弹"。  相似文献   

Aspect of the specialty metals potentials of pegmatites in western Oban Massif, SE Nigeria: A preliminary geochemical approach     

Oden M.I.  Igonor E.E. 《中国地球化学学报》2012,31(4):355-361

Minerals in general and rare-metals in particular are of invaluable importance in the development and industrialization of any nation.This is true as they could affect a nation’s national income,employment ratio,Gross National Product,and its entire economy.The study area(western Oban Massif-SE Nigeria) was investigated for its specialty metals bearing potentials because of(1) its geology,which is similar to other specialty metals bearing areas of the world;(2) past works,which points to the area as a likely source of economic deposit of such metals;and(3) the soaring cost of these rare metals in the light of recent upsurge in global information/telecommunication technology.Results from the study,show that only cesium(Cs) and beryllium(Be) show minute signs or indications of enrichment if properly harnessed.Thus these metals should be studied in details to ascertain their economic potentials.The rocks are too deficient in the other rare-metals(lithium,zirconium,strontium,tantalite,niobium,tungsten,gallium,and chromium) to warrant further analysis.  相似文献   

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance     

G. Parthiban 《Marine Georesources & Geotechnology》2013,31(3):223-235

Abstract

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m^?2 day^?1. Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (～4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ～5 days showed a reduction in particle fluxes of ～50%, indicating rapid particle settlement.  相似文献   

沉积物暴露条件下文蛤Meretrix meretrix 对重金属Cu、Pb的富集动力学研究          下载免费PDF全文

李磊  王云龙  沈盎绿  蒋玫  黄厚见  沈新强 《热带海洋学报》2013,32(1):70-75

应用半静态双箱动力学模型室内模拟了沉积物暴露条件下文蛤Meretrix meretrix 对Cu、Pb的生物富集,通过对富集与排出过程中文蛤体内重金属污染物的动态监测和对富集与排出过程监测结果的非线性拟合,得到了文蛤富集重金属的吸收速率常数K₁、排出速率常数K₂、生物富集因子BCF(bioconcentration factors)、生物学半衰期B_1/2等动力学参数。拟合结果得到的Cu、Pb各动力学参数分别为,K₁为4.6333—72.3754;K₂为0.0512—0.0798;BCF为60.7646—1414.9634;B_1/2为8.69—13.55。对模型的拟合优度检验结果显示,沉积物暴露条件下文蛤对重金属Cu、Pb的生物富集数据符合双箱模型,模型的拟合优度良好。比较结果得出,吸收速率常数K₁及生物富集因子BCF均随着外部水体金属暴露浓度的增大而减小;文蛤对Cu富集能力大于Pb;Cu在文蛤体内的生物学半衰期B_1/2大于Pb;理论平衡状态下生物体内Cu、Pb的含量C_Amax随着外部水体中金属暴露浓度的增大而增大,且呈显著正相关,实验结果表明沉积物暴露条件下双箱动力学模型在一定条件下是可以应用于文蛤的富集动力学研究的,仍需要进一步开展不同条件下实验研究分析。  相似文献