首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Preliminary geochemical mapping was carried out within urban areas in Tampere Central Region, Finland, to gain a better understanding of element concentrations in urban soil and to provide information on baselines in soil within urban centres for soil contamination assessment purposes. The soil samples were taken from central city parks, day-care centres and school yards, and residential areas. Various sampling depths have generally been used in urban geochemical surveys. The aim of this study was to compare the results from two commonly used sample types taken from the same sites in urban soil: single samples of minerogenic topsoil from the 0–25 cm layer and composite samples of minerogenic topsoil from a depth of 0–2 cm. The concentrations of most of the studied trace elements showed a significant correlation between samples from 0 to 2 and 0 to 25 cm, but element concentrations differed between the two studied sample depths. For most of the studied elements, the median concentrations were higher in the 0–25 cm samples, but anomalous concentrations were more often found in the 0–2 cm samples. Some elements had elevated concentrations when compared with the Finnish guideline values for soil contamination assessment. This study did not conclusively establish whether a sampling depth of 0–2 or 0–25 cm should be recommended for similar studies in the future. Selection of the sampling depth in geochemical studies greatly depends on the aim of the project. In order to determine the upper limits of geochemical baseline variation, the deeper sampling depth appears to be more feasible. However, for the preliminary health risk assessment of areas with sensitive land uses, e.g. children’s playgrounds, samples from 0–2 cm depth are considered informative. Such samples may also be used to indicate local sources of dusting creating site-specific hotspots of potentially harmful elements in urban topsoil.  相似文献   

2.
The potentially hazardous contents of mine tailings can pose a serious threat to the environment. Tailings dispersed around the abandoned Monica mine (Bustarviejo) in the Autonomous Region of Madrid (Central Spain) were studied to determine the concentration of several potential toxic elements and their geochemical impact in the surrounding soils. A total of 17 surface soil samples were collected from both mixed sulfide mine tailings sites and unmined soils, within a radius of 1900 m from the mine entrance. The processing of minerals (basically arsenopyrite, matildite and sphalerite) produced tailings with a pH as low as 2.9. Elements such as As, Cu, Zn, Cd, Pb, W, Ag, Fe were found in very high concentrations, contaminating the soil to varying degrees (these elements were sometimes 10- to 20-times higher in the tailings than in the unmined soils). Given its short distance and accessibility from such a large city as Madrid, it is of undeniable environmental and educational interest. Among other factors, there is a need for improvements to tailings management strategies.  相似文献   

3.
人为活动对江苏土壤元素含量分布的影响   总被引：1，自引：0，他引：1       下载免费PDF全文
廖启林  华明  张为 《江苏地质》2012,36(2):147-156
通过对江苏1∶25万多目标区域地球化学调查及典型地区生态地球化学评价资料的宏观分析与对比,认为人为活动对地表土壤的元素含量分布具有显著影响,表层土壤(0～20cm深度)中Cd、Hg、Se、S、Sn、N等代表性元素的含量大幅度增加,元素含量变异系数偏高,酸碱度(pH值)下降趋势明显,确定了S、Hg、Cd、Se、pH、TOC、N、P、Sn、Sb、Pb、Zn等是最能反映人为活动对土壤环境之影响的地球化学指标。施肥、工业排污等均是人为活动改变土壤元素含量分布的基本形式。  相似文献   

4.
This study investigates the stratigraphical sequence of Cocina Cave (Spain) employing and testing for the first time the capability of rare earth elements as markers of human activities in caves. Located in Dos Aguas (Valencian Community, Spain), Cocina Cave is characterized by the presence of several Holocene archaeological deposits from the final Mesolithic to the present day and is a pivotal site for understanding the socio-ecological dynamics of the last hunter-gatherer inhabitants of the Iberian Peninsula and the transition to pastoral and agricultural economies in the Western Mediterranean. However, the identification of strata from particular time-periods in the cave is often difficult due to the homogeneity of layers, the poor archaeological record in some strata and the presence of severe disturbance phenomena. The methodological approach of this study consisted of cross-referencing rare earth elements and other chemical markers with the archaeological stratigraphical interpretation, in an attempt to not only support the identification of the anthropic contribution to the formation of Cocina Cave strata, but also to characterize and confirm different natural and occupational episodes, particularly those associated with hunter-gatherer, early agriculturalist, and shepherd activities. Sediments were collected from different excavation areas and analysed for major elements, trace elements, rare earth elements (REE), soil organic matter (SOM) amounts and pH. Multivariate statistics were employed to group samples according to their elemental profile, and these were then compared to the archaeological temporal interpretation. The obtained results showed that REE amount and fractionation geochemical processes were regulated by carbonates, phosphates and pH. The use of REE as markers was particularly useful as their concentrations and their calculated ratios and anomaly distributions were demonstrated to be highly consistent with the archaeological stratigraphical interpretation.  相似文献   

5.
The present study aims to interpret the occupation of terra firme (nonflooded uplands) archeological sites located at Tapirapé‐Aquiri National Forest in the Brazilian state of Pará, through an integrated analysis of pedological, archeological, and geochemical data. We focus on seven archaeological sites, selected among 22 identified in the region. Radiocarbon and thermoluminescence dating indicate distinct periods of occupation over the past ∼6000 years, and the pedo‐geochemical data identify intra‐ and inter‐site differences in soil. Archaeological, chronometric, and pedo‐geochemical data provide a basis for the functional classification of archeological sites found in the region and help to identify specific human activity areas. The results lead us to infer that many of the archeological sites were the result of multiple occupations that left a persistent pedological signature on the landscape.  相似文献   

6.
洞庭湖区澧阳平原有全国最密集、文化序列最清楚的史前遗址,是研究人与自然关系演变过程的重要地区。该区的文化层不仅蕴含了考古文物资料,而且赋存了大量的古代自然与人文环境的信息,其地球化学记录为解读人地关系提供了一把钥匙。通过对21处遗址114件不同时代的文化层及其生土层、表土层样品的地球化学特征的研究,认为文化层的常量元素更多地反映了自然环境的状况,新石器中期以后的文化层的微量元素则反映了人类活动的特征。不同时期文化层的元素组合反映了不同自然与文化阶段的古代自然和人文环境的特征,据其地球化学综合指标的分类可获得关于文化和环境演化统一性和阶段性的本质认识。  相似文献   

7.
 Two waste-disposal sites (old and new) in Calabar Municipality, SE Nigeria were evaluated to assess their suitability as landfill sites and their impact on the groundwater. The field investigation included surface geological/hydrogeological and geochemical studies. Leachate and groundwater were sampled and analysed for 3 months (April, May and June, 1997) for geochemical characterisation. The results indicate that the two waste-disposal sites in the Calabar Municipality do not meet the requirements as landfill sites. Physico-chemical analyses for temperature, pH, conductivity, dissolved oxygen, biological oxygen demand after 5 days of incubation (BOD5), sulphate, nitrates, nitrite, trace and major elements in the leachate known to impact human health and the environment, indicate high levels of pollution. The values for groundwater in the vicinity of the disposal sites were found to be within the World Health Organisation (WHO) permissible limit. Received: 29 March 1999 · Accepted: 3 January 2000  相似文献   

8.
河水理化性质和元素组成特征直接影响到水体利用功能,入海河流元素输送量对近岸海洋生态环境具有重要影响。在中国东部33条入海河流下游河段或河口区布设了水地球化学调查点,分别在2007年夏季(丰水期)、2007年底—2008年初(枯水期)采样并测定了河水酸碱度、电导率值以及溶解态常量和微量元素浓度。研究表明,多数北方河流水体酸碱度、电导率值以及常量元素浓度高于南方河流,与中国土壤及其常量元素组成的南北分带相吻合,反映了我国南北气候分带对河水地球化学特征的控制作用,推断少数河流酸碱度、电导率和常量元素浓度的异常分布与海水混合作用、人为污染等作用有关;部分河流水体中微量元素浓度背离于区域正常浓度,其原因一是与区域地球化学背景有关,二是与城市污染影响有关,通过对比部分城市上、下游水体元素浓度证实城市污染的影响;研究认为丰水期易溶元素Na、Ca、K、Zn、Se浓度较低反映了大量降水的稀释效应,而丰水期河水Al、REE、Fe、Pb、Tl等元素浓度明显高于枯水期,主要与丰水期暴雨形成的地面径流携带大量胶体颗粒进入地表水有关。  相似文献   

9.
安徽省江淮流域土壤地球化学基准值与背景值研究   总被引：13，自引：0，他引：13       下载免费PDF全文
基于安徽省江淮流域多目标区域地球化学调查数据资料,统计获得了表层和深层土壤地球化学基准值、背景值及相应的地球化学参数,为研究区生态环境评价及相关学科研究提供了基础。研究表明,成土母质类型对土壤元素地球化学基准值影响显著,表层土壤化学组成表现出既对深层土壤具有一定的继承性,又在表生作用下发生某些变化:表层土壤中迁移活动性强的元素和人为扰动污染的元素明显不同于深层土壤;随着地理空间位置的变化,同类成土母质形成环境、成因来源的差异导致其化学组成的空间变异,造成不同地区同类成土母质地球化学基准值有所不同。因此,土壤地球化学基准值研究应更多地考虑地质背景、物质来源等因素的影响。  相似文献   

10.
湘中HJC铀矿区黑色页岩土壤重金属污染地球化学分析   总被引：13，自引：0，他引：13  
本文以湘中HJC铀矿区黑色页岩土壤为研究对象,对黑色页岩土壤重金属污染进行了地球化学分析。通过测制A、B、C、D等土壤剖面并系统取样,借助ICPMS等分析技术,对土壤、成土母岩、玉米等进行了系统的主量元素、重金属和其他微量元素（稀土元素）分析。结果表明,矿区黑色页岩土壤具富Al2O3、Fe2O3,而贫CaO、Na2O的化学组成特征,其化学风化指数CIA值在79~84之间。土壤因继承成土母岩的元素富集特征而富集V、Cr、Co、Ni、Cu、Zn、Mo、Cd、Sn、Sb、Tl、Pb、Th、U等多种重金属,其中Mo、Cd、Sb、U的富集最强。土壤重金属综合富集指数（EI值）在3~9之间,各剖面EI值大小顺序是：D>A>B>C, 以D剖面土壤重金属综合富集最强。土壤重金属污染富集因子（F）评价结果显示：矿区土壤普遍存在Cd、Mo、Sn、Sb、U等重金属污染,其中Mo、Cd、Sb等的污染最强,达显著（3级,2 < F < 20）污染程度以上。重金属污染效应既表现为Sc、Cd、Sn、Sb、U、Tl、Pb等生物毒性重金属在玉米中的富集,又表现为Mo、Co、Ni、Cu、Zn等生物有用金属在玉米中的明显亏损。黑色页岩即为土壤重金属污染的污染源。土壤重金属污染与重金属在成土母岩和土壤中的富集程度(Ks、EI、F)、重金属的活动性（Change%）等多种因素有关。重金属污染主影响因子的Pearson相关系数分析显示：Cd对土壤构成持久性污染,Mo、Sn、Sb、U等的污染程度可随土壤风化的进行因淋失而趋于降低,而Zn、Mn、Ba、Co、Ni、Th等目前未达到污染水平的重金属则可因次生富集而在未来引发污染。  相似文献   

11.
《Applied Geochemistry》2001,16(1):123-136
Concentrations of several elements extractable with BaCl2 and acid ammonium acetate (pH 4.65) were measured in the organic and 4 mineral soil layers on the national forest inventory plots of the Finnish Forest Research Institute. The soil data also includes total concentrations of elements in the organic layer and site and soil physical characteristics. Data were compared with the aqua regia extractable element concentrations measured in the nationwide regional till geochemical mapping carried out by the Geological Survey of Finland.Correlations between concentrations in surface soil and underlying basal till were generally highest for K, Mg, Mn, P and Zn; in the organic layer and till they were highest for Cr and Cu. The strength of these correlations did not increase regularly from surface to deeper soil layers. All soil base cations with the exception of Ca, which is of relatively low solubility, were well correlated. The elements Zn, K, P, Al and Mn in till were the most reliable indicators of surface soil chemistry.Fuzzy clustering showed that the correlation between element concentrations in basal till and the two uppermost layers of mineral soil was better within areas of distinct till geochemistry, such as the schist belts in southwestern Finland, the Lake Ladoga–Bothnian Bay zone and the Kuusamo schist belt.Surface soil chemical variables were clearly better in discriminating fertility classes of forest sites than were element concentrations in basal till. The independent ability of till geochemistry to distinguish these productivity classes and to explain surface soil fertility was nevertheless demonstrated.  相似文献   

12.
In parts of the deeply weathered and semi-arid environments of the Cobar area (NSW, Australia), detection of mineralisation using conventional soil sampling and total metal analysis is impeded. This is due to the intense leaching of trace elements within the weathered profile, discontinuous coverage of transported materials and the existence of diffuse regional geochemical anomalies of ill-defined source. Selective chemical extractions, applied to various regolith components, and biogeochemistry offer a means of isolating localised geochemical patterns related to recent dispersion of trace elements through the overburden. Lag geochemical patterns across the McKinnons deposit (Au) and Mrangelli prospect (Pb–Zn–As) reflect mechanical dispersion processes and minor hydromorphic effects. Concentrations of more mobile elements tend to be higher in the non-magnetic fraction, due to higher proportions of goethite and poorly crystalline hematite than in the magnetic fraction. The subdued soil geochemical responses for metals extractable by cold 40% hydrochloric acid (CHX) and for total element concentration reflect the leached nature of the residual profile, low grade of mineralisation, dilution by aeolian components and disequilibrium of fine fractions with coarser, relict Fe-oxides. The stronger contrast for CHX for most metals, compared with total extraction, indicates surface accumulation of trace elements derived from underlying mineralisation. Enzyme leach element anomalies are intense but generally located directly over bedrock sources or major structural breaks, irrespective of the nature of the overburden. Though mechanisms for the dispersion of trace elements extracted by enzyme leaching are not well established, the lack of lateral transport suggests vertical migration of volatile metal species (atmimorphic dispersion). The strong, multi-element response to mineralisation in cypress pine needles indicates significant metal recycling during the present erosional cycle. However, a comparison of the trace element concentrations in vegetation (cypress pine needles) and selective extractions of soils indicates that recycling by the plants is not the dominant mechanism for transportation of metals through the overburden. The vegetation may be responding to hydromorphic dispersion patterns at depth. The use of selective extractions may be useful in detecting mineralisation through deeply leached profiles, but offers even greater potential when integrated with biogeochemistry to detect targets buried by significant thickness of transported cover.  相似文献   

13.
文章以浙江省平湖市为典型三角洲平原区,开展了多种尺度、不同采样方法的对比试验。结果表明,田块内土壤元素分布较为均匀,小范围内元素的空间分异性较小,而田块之间土壤元素含量差异性明显增加;Hg,Cd等典型污染元素空间分异性较强,而人为污染扰动较弱的元素的空间分布较为均一;不同采样方法取得的区域性资料,其统计值接近,空间分布模式也相似,但有些元素仍有较明显差异。因此,中大比例尺地球化学调查时,应根据调查研究的目标任务,充分考虑地块分布、土壤类型和土地利用方式,选择合理的采样点。土壤样品可采取多坑点采集、多子样组合的方式,以保证样品的代表性,同时减少分析测试工作量。  相似文献   

14.
Multi-matrix environmental monitoring was used to evaluate the influence of a municipal solid waste landfill (Ginestreto, Emilia Romagna, Italy) on the level and distribution of heavy elements in the surrounding environment (air, soil and soil biota). Concentrations of As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Tl and Zn were measured by inductively coupled plasma-mass spectrometry in transplanted lichens, topsoils and isopods. The highest accumulation levels found for Cd, Cr, Pb, Sb and Zn in lichens transplanted within the Ginestreto landfill. However, similar concentrations of these heavy elements were also found in lichens exposed in monitoring sites influenced by other man-made sources, such as vehicle traffic and truck movements. The fallout of heavy elements emitted by the landfill had low impact on their levels in topsoil: Cd, Cr, Pb, Sb and Zn showed higher contents in topsoil collected close to the landfill and a slight decrease in concentrations with increasing distance from the landfill. There was no variation in heavy element accumulation in isopods in relation to distance from the landfill. The results of this study indicate that the Ginestreto municipal solid waste landfill had limited impact on the environmental distribution of heavy elements, since accumulation and enrichment in lichens and topsoils were only detected close to the landfill, up to about 100 m from its border.  相似文献   

15.
Phosphorus (P) and other chemical elements have been used to identify residential middens at archaeological sites. This study discusses the relationship of soil chemical elements and middens at Group Chispa, a Late Classic residential complex at a commoner village in the Maya lowlands. The complex was extensively excavated and soil sampled. Ceramic sherd densities, which serve as a proxy for artifact densities, correlate only partially with phosphorus and other chemical elements. One of the three middens in Group Chispa coincides with the highest concentration of P while the two others—including the most extensive one—have medium to low P levels. A spectrum of human activities that include the preparation of pigments explains the nontraditional distribution of chemical elements. High P levels remain useful to detect middens but they provide an incomplete picture and need to be contextualized by comprehensive archaeological data.  相似文献   

16.
Although the term ‘geochemical baseline’ appears in the international geochemical mapping programmes IGCP 259 and 360, it has never been well defined. Several considerations relevant to such a definition are discussed. A geochemical baseline for an element refers to its natural variations in concentration in the surficial environment. Geochemical baselines were studied in Finland by comparing results from regional geochemical mapping programmes based on samples of till, clay and organic stream sediment. The geochemical background changes regionally with the basic geology and locally with the type and genesis of the overburden. Baseline concentrations depend on sample material collected, grain size and extraction method. In Finland, concentrations of potentially harmful elements tend to be higher in fine-grained marine and lacustrine sediments than in glacial till. Concentrations are also systematically higher in the < 0.06 mm fraction than in the < 2 mm size fraction of till samples. Only small proportions of the total heavy metal concentrations in Finnish marine clays are bioavailable. Geochemical baselines are needed for environmental legislation and political decision-making, especially in the assessment of contaminated soil. In many areas of Finland, natural concentrations of several heavy metals exceed the guide or limit values designated for contaminated soils. Thus baselines must always be verified in any assessment of sites for contamination.  相似文献   

17.
The behaviour of the rare-earth elements(REE)during the weathering of granites was studied in southern Guangxi,China.Based on the study of the weathering profiles,the soil,weathered and sub-weatereb zones are identified with different REE geochemical behaviours throug the weathering profiles of granite.The Ce anomalies of the weathering profiles cover a large range of values with most falling between 1.02 and 1.43in the soil zone and 0.16and 0.40in the weathered and sub-weathered zones.Light rare-earth elements(LREE) and heavy rare-earth elements(HREE)are enriched to varying degree in the weathering profiles as compared to host granites.In the soil zone,more HREEs are leached than LREEs,and HREEs are more enriched than LREE in the weathered and sub-weathered zones.It is considered that infiltration and adsorption on clays are two processes controlling the enrichment and formation of REE deposits in the weathering profiles of granite.  相似文献   

18.
Thirty-nine elements in humus and till matrix were compared at 109 sites overlying Ag–As–Cu–Mo–Pb–Zn mineralized occurrences in northeastern New Brunswick to assess humus for anomaly identification. Humus element concentrations were not consistently correlative with maximum or minimum concentrations found in the underlying till or bedrock. The humus demonstrated significantly higher mean elemental concentrations than the till for six specific elements: 9 times greater for Mn, 6 times greater for Cd, 5 times greater for Ag and Pb, 3 times greater for Hg, and double the concentration of Zn. Spatial dispersal patterns for these elements were much larger for humus content than that exhibited by the till matrix analysis, but did not delineate a point source. For elements in till, the highest concentrations were commonly found directly overlying the underlying mineralized bedrock source or within one km down-glacier of the source.The complexity of the humus geochemical patterns is attributed to the effects of post-glacial biogenic, down-slope hydrodynamic and solifluction modification of dispersed mineralization in the underlying till, and the greater capacity of humus to adsorb cations and form complexes with some elements, relative to the till matrix. Humus sampling in areas of glaciated terrain is considered to be mostly valuable for reconnaissance exploration as elements can be spatially dispersed over a much larger area than that found in the till or underlying bedrock.  相似文献   

19.
During excavation at Calderwood Buffalo Jump (DkPj-27), southern Alberta, two profiles were sampled for soil chemical analysis. Transect samples were subjected to the phosphate ring test. The study objectives were to examine the effects of bison-jump use on the soil profile, to investigate whether discrete jump-use episodes could be identified within the soil profile, and to see if the ring test was useful in site delimitation. Comparative off-site profile samples exhibited the normal Ahk, Bmjk, and Ck sequence of a Rego Black Chernozemic soil. In contrast, samples from the primary excavation unit were enriched in organic matter and phosphorus with lower pH and higher fatty acid content. These data indicate that organic input from jump use has had a substantial impact on soil characteristics and development. A ring chromatography field test for available phosphate indicated higher values in this vicinity, suggesting the utility of this method in rapid and relatively non-destructive field survey of similar sites. The soil chemical data suggest continuous rather than episodic jump use, contrasting with four specific episodes of jump use over the last 2800 years inferred from archaeological data.  相似文献   

20.
This paper describes a research program to determine if a geochemical signature is retained in surface and sub-surface soils over a well-contained underground nuclear explosion. Samples of soil at surface and about 10–15 cm below were collected on orthogonal traverses up to about 1 km from ground zero (GZ, surface projection of blast point) at three locations in central (Ville) and southern Yucca Flat (Laredo and Presidio) on the Nevada Test Site (NTS). They were analyzed for total element content by instrumental neutron activation (INAA) and, using selective leaches, for partial element content, namely that amount bound to amorphous Fe oxyhydroxide and that amount bound to Mn oxide. Forty-two elements were determined in these leaches of both surface and sub-surface soils, by inductively coupled plasma mass spectrometry (ICP-MS), ICP emission spectrometry (ICP-ES) and hydride generation quartz tube atomic absorption spectrometry (HG-QTAAS). These partial leaches were chosen on the premise that the extreme temperature and pressure conditions created by an underground blast would volatilize elements in the surrounding rock and transport them along with fission products to the surface where they would be trapped by these phases in the soil. The INAA data generally show consistent concentrations of major, minor and trace elements within each location. In contrast, the selective leach data show distinct geochemical anomalies in numerous elements. Iodine, As, Mo, and U demonstrate particularly consistent positive anomalies at and around GZ at all three locations by both leaches. The amplitudes of these anomalies can exceed two orders of magnitude over background, particularly for I. This positive response is shown by more elements associated with Mn oxide than associated with Fe oxyhydroxide at all three locations; furthermore these patterns are more coherent and intense for some elements. The Mn oxide phase itself is more consistently distributed than is the Fe oxyhydroxide phase at the sites within each location. In most cases, significant depletion of Fe as amorphous Fe oxyhydroxide coincides with the multiple positive anomalies in this phase. The number and group of elements displaying distinct patterns is dependent upon the location as well as on the leach. The concentration ranges of elements extracted from the Fe oxyhydroxide or Mn oxide phase are similar for sites at Laredo and Presidio but dissimilar from those at Ville, probably a reflection of the differing geological settings. Whereas some anomalies are spatially quite compact, extending only about 50 m from GZ (e.g. Rb, Cs, Th), others such as I and Sb extend up to 300 m. The geochemical behaviour of the surface soil samples, although slightly noisier, is similar to that of the sub-surface suite. These results indicate that analysis of specific geochemical phases in soils over a suspected underground nuclear test has an important role in the on-site inspection component of the verification of the Comprehensive Test Ban Treaty.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号