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1.
High concentrations of metals in organic matter can inhibit decomposition and limit nutrient availability in ecosystems, but the long-term fate of metals bound to forest litter is poorly understood. Controlled experiments indicate that during the first few years of litter decay, Al, Fe, Pb, and other metals that form stable complexes with organic matter are naturally enriched by several hundred percent as carbon is oxidized. The transformation of fresh litter to humus takes decades, however, such that current datasets describing the accumulation and release of metals in decomposing organic matter are timescale limited. Here we use atmospheric 210Pb to quantify the fate of metals in canopy-derived litter during burial and decay in coniferous forests in New England and Norway where decomposition rates are slow and physical soil mixing is minimal. We measure 210Pb inventories in the O horizon and mineral soil and calculate a 60-630 year timescale for the production of mobile organo-metallic colloids from the decomposition of fresh forest detritus. This production rate is slowest at our highest elevation (∼1000 m) and highest latitude sites (>63°N) where decomposition rates are expected to be low.We calculate soil layer ages by assuming a constant supply of atmospheric 210Pb and find that they are consistent with the distribution of geochemical tracers from weapons fallout, air pollution, and a direct 207Pb application at one site. By quantifying a gradient of organic matter ages with depth in the O horizon, we describe the accumulation and loss of metals in the soil profile as organic matter transforms from fresh litter to humus. While decomposition experiments predict that Al and Fe concentrations increase during the initial few years of decay, we show here that these metals continue to accumulate in humus for decades, and that enrichment occurs at a rate higher than can be explained by quantitative retention during decomposition alone. Acid extractable Al and Fe concentrations are higher in the humus layer of the O horizon than in the mineral soil immediately beneath this layer: it is therefore unlikely that physical soil mixing introduces significant Al and Fe to humus. This continuous enrichment of Al and Fe over time may best be explained by the recent suggestion that metals are mined from deeper horizons and brought into the O horizon via mycorrhizal plants. In sharp contrast to Al and Fe, we find that Mn concentrations in decomposing litter layers decrease exponentially with age, presumably because of leaching or rapid uptake, which may explain the low levels of acid extractable Mn in the mineral soil. This study quantifies how metals are enriched and lost in decomposing organic matter over a longer timescale than previous studies have been able to characterize. We also put new limits on the rate at which metals in litter become mobile organo-metallic complexes that can migrate to deeper soil horizons or surface waters.  相似文献   

2.
孙淳浩  余丹  王冬艳  李文博 《世界地质》2018,37(4):1301-1308
基于吉林省中部黑土区地球化学调查数据,分析统计As、Cd、Cr、Cu、Ni、Zn 6种可造成重金属污染的元素在土壤--作物系统中的生态地球化学特征。通过吉林省部分地区土壤样品与玉米籽实样品采样,采用元素有效系数与元素累积系数的方法,计算出采样点的土壤重金属元素全量、有效量和玉米籽实含量特征,从而研究重金属元素生态地球化学特征。结果表明:(1)研究区土壤重金属元素全量虽然较吉林省土壤元素背景值增加明显,但土壤与玉米籽实均未达到污染状态。(2)重金属元素有效系数均值由小到大依次为As Cr Zn Cu Ni Cd,在研究区的空间分布差异性较大;玉米籽实积累系数均值由小到大依次为Cr As Ni Cd Cu Zn,在的空间分布差异性相对较小。(3)吉林省中部黑土区的玉米籽实重金属元素积累程度均较低,在未发生土壤重金属元素污染的清洁土壤中,Cu与Zn对于玉米植株来说,属于必需营养元素范畴;重金属元素中Cd的有效系数大,作物可食部分积累程度较高,应注意其预防与治理工作; As与Cr的有效系数较小,可能是导致其在玉米籽实中积累程度较低的主要影响因素之一; Ni在土壤中有效态转化程度较高,玉米籽实Ni吸收量相对较低。(4)多数重金属元素在玉米籽实中的累积程度与其在土壤中的有效系数呈正相关关系。  相似文献   

3.
The purpose of this study was to examine the influence of parent sediment material on soil geochemistry and to locate possible pollution sources in the area of Turku town in southwestern Finland. The study area is glaciated terrain and subsurface samples were chosen to represent five different parent sediment materials: glacial till, glaciofluvial or littoral sand, clay, peat and marine mud. Elemental concentrations of surface (100 samples) and background soil (50 samples) were analysed by ICP-AES (Al, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Sr, Ti, V) and by graphite furnace AAS (As, Cd, Mo, Se). Loss-on-ignition was determined as an indicator of organic matter. Analytical results were examined using multivariate statistical methods. The results indicate that the studied soils are not heavily contaminated; there were only few sample sites with elevated heavy metal concentrations. High Pb concentrations were observed along main traffic routes, and also in places where there has been small-scale use of antifouling paints. However, concentrations of heavy metals in topsoil were in general significantly lower than those measured in large cities elsewhere. The parent material strongly affects the geochemical character of the soils. Clays naturally have a significantly higher concentration of heavy metals than sands or till material. This is also reflected in concentrations in organic topsoil. When assessing target levels for polluted soil, the primary sediment appears to be a more important factor than the amount of organic matter.  相似文献   

4.
The distribution and controls of trace elements (Cd, Cr, Cu, Ni, Pb, Zn and U) in shallow groundwater in discharge and recharge zones were analysed at two sites on the Baltic coast of Sweden; one granite-dominated and one with a significant addition of calcite. Although the study sites differ in overburden geochemistry and groundwater trace metal concentrations, which were well reflected in the general groundwater composition, the relative hydrochemical differences between recharge and discharge ground waters were similar at both sites, and temporally stable. The concentrations of Cd, Cu, Ni and U were higher in soil tubes in recharge areas, but Cr was higher in discharge zones. Also concentrations of HS, Fe, Mn and NH4 were higher in discharge samples, which in combination with increased 34S values provide strong evidence of a transition from oxidizing to more reducing conditions along the groundwater flow gradient. In terms of trace metals, this might mean either mobilisation due to dissolution of trace-metal carrying Fe(III) and Mn(IV) phases, or immobilisation caused by precipitation of discrete trace-metal sulfides or co-precipitation with Fe sulfides. The results from this study show that the latter is dominant in both the carbonate and granite environments for the metals Cd, Cu and Ni. Chromium concentrations were likely coupled to organic complexation and were higher in discharge groundwater, where DOC was also more abundant. As the concentration of several potentially toxic trace metals were found to differ between recharge and discharge areas, a climate driven change in hydrology might have a substantial impact on the distribution of these metals.  相似文献   

5.
《Applied Geochemistry》2005,20(7):1258-1267
Distributions of 21 major and trace elements in HNO3 extracts of different horizons were studied in 13 podzol profiles from the boreal forest in different parts of Norway using ICP–MS. On the basis of ratios between the HNO3-extractable fractions in the various horizons some general trends were elucidated. Two different groups of elements concentrated in the humus layer relative to the mineral horizons were identified, one mainly associated with contributions from air pollution (As, Cd, Sb, Pb), another one with plant nutrient circulation (K, Ca, Mn and to a lesser extent Mg, Co, Ni, Rb) and some with both mechanisms (Cu, Zn, Tl). The elements most clearly enriched along with Fe in the B horizon were V, Pb, Al, and Cr in that order, Pb partly because of leaching from the polluted organic surface soil. Four soils in the far south showed a behaviour distinctly different from the rest and were treated as a separate group. Relative to the more northerly sites the surface horizons of these soils were strongly depleted in lithogenic elements (Mg, Al, K, Ca, Sc, V, Cr, Mn, Fe, Co, La) and enriched in elements typical of long-range transport of pollutants (As, Cd, Sb, Tl, Pb). Also the B horizon in the southern soils was strongly depleted in the lithogenic group elements, including Fe and the associated metals. The main reason for this difference is assumed to be the greater influence of transboundary air pollution and associated metals and stronger soil acidification in the far south of the country.  相似文献   

6.
Eight catchments, an area of 15 to 35 km2, have been studied within an ecogeochemical mapping programme in the western Kola Peninsula and contiguous parts of Finland and Norway. Three catchments, one northeast of Zapolyarniy (1) and two, 5 and 25 km south of Monchegorsk (2 and 4) show high levels of deposition of heavy metals, especially nickel (Ni) and copper (Cu), related to the metallurgical industry in these cities. Twenty-five topsoil samples, from sites evenly distributed over catchment 2, have mean contents of Ni and Cu 1 to 2 orders of magnitude higher than both C-horizon samples from the same sites and topsoil samples from catchment 4, providing strong evidence for the anthropogenic origin of the heavy metals. The same samples show geometric mean total contents for the noble metals analysed of: 1.4 μg/kg rhodium (Rh), 49.6 μg/kg platinum (Pt), 187.6 μg/kg palladium (Pd) and 9.5 μg/kg gold (Au). The pattern of concentration of the noble metals mirrors that found in published averages for ore from the Talnakh mineralizations in the Noril'sk province, though 1–2 orders of magnitude lower. This also clearly shows that the noble-metal contents of the topsoil are anthropogenic, and suggests that they emanate from the plants in Monchegorsk at an early stage in treatment of the ore, probably as a minor component of Ni-Cu rich particles. The noble-metal geochemistry of the topsoil in the other catchments also reflects the nature of the ore being processed at the plants nearby.  相似文献   

7.
青岛城区土壤重金属环境地球化学研究   总被引：13，自引：4，他引：9       下载免费PDF全文
为研究青岛城区土壤的环境地球化学特征,对青岛市南区、市北区、四方区、李沧区、崂山区5区进行了广泛的土壤地质调查。在每1km2一个样品的取样密度下取得表层土样(0～10cm深度)319个,经前期处理后,利用多种仪器如X射线荧光光谱(XRF)、等离子体发射光谱(ICP-OES)和等离子体质谱(ICP-MS)等分析测得所有样品的72种元素的含量,本文探讨了重金属元素Cd、Cr、Cu、Ni、Pb和Zn及类金属元素As的含量分布。结果表明,人类活动导致表层土壤中元素Cd、Cu、Pb和Zn含量的增加,而元素As、Cr和Ni主要是地质起源,但也会受到人类活动的影响。其中Zn的含量值变化较大,Zn元素含量值增高的地区是工业、交通密集处等人类活动频繁的地区。  相似文献   

8.
鲁照玲  胡红云  姚洪 《岩矿测试》2012,31(2):241-246
分别采用HNO3-HF、HNO3-HF-HCl和HNO3-HF-H2O2三种消解体系,通过微波和PTFE密封罐电热板对土壤标准物质进行前处理,采用电感耦合等离子体质谱(ICP-MS)对样品中的重金属元素Cr、Ni、Cu、Zn、As、Cd和Pb进行定量分析。探讨了前处理试剂(主要为HNO3、HCl和HF)以及土壤基体效应对Cr、Ni、Cu、Zn、As、Cd和Pb定量分析的影响。研究结果表明,前处理试剂对Cr、Ni、Cu、Zn、As、Cd和Pb的定量分析具有不同程度的影响;对于土壤基体,在三种消解体系下均可观察到基体抑制效应;采用PTFE密封罐电热板消解方法前处理,待测元素及相同元素不同同位素的方法空白和检出限均较低,效果整体优于微波消解法。特别是HNO3-HF-HCl消解体系,通过选用52Cr、60Ni、65Cu、66Zn、75As和206Pb等同位素,重金属元素Cr、Ni、Cu、Zn、As、Cd和Pb的测定值均能保证在标准值的允许误差范围内,可以满足大批量土壤样品中重金属元素同时定量分析的需要,为高效准确地开展土壤的风险评估以及为土壤的修复治理提供科学依据。  相似文献   

9.
Lerma River is one of the largest rivers in Mexico. Over the past 20 years, unplanned population growth occurred along its course and the river has been used as the only outlet for industrial and domestic wastewater disposal. The aim of the present study was to determine trace metals such as Cr, Ni, Cu, Zn, Fe, Pb, and arsenic concentrations at the upper layer of sediments of the Lerma River meander in La Piedad, Michoacan, Mexico. Sediment samples were collected from eight different sites during the rainy and dry seasons. All samples were physically characterized, and concentration values of trace metals and As were determined. On the basis of protection criteria for freshwater sediments, concentrations of Fe, Zn, Cu, Ni, and Pb were found to exceed the lowest effect level; moreover, the concentrations were found to exceed the severe effect level at some sites, particularly for Cu. Statistical analyses showed significant differences between sampling seasons for Fe and As, and among sites for Ni, Cu, Zn, and Pb. In addition, the enrichment factor indicates the following order Zn > Cr > Cu > Ni > Pb > As, and the geoaccumulation index (I geo) indicates contamination in the following order Zn > Cr > Cu > Ni > As > Pb. The Lerma River meander in La Piedad shows a reduction in pollution by trace metals and arsenic near the drain area and downstream of the meander. However, there are significantly higher concentrations of these elements in sediments of sites located in the middle part of the city.  相似文献   

10.
Samples were collected at 71 sites in the Yellow River Delta Natural Reserve in December 2010 to represent soil conditions before and after the Yellow River (YR) diversion. The As, Cd, Cu, Pb, Zn, and Ni concentrations were measured to determine metal contamination levels. Results suggest that Cd concentrations were significantly higher after the YR diversion than before. The As, Cd, Cr, Cu, Ni, Pb, and Zn soil contamination indices did not exceed contamination levels, although the heavy metal content increased after the YR diversion. The mean concentrations of these heavy metals were lower than the Class I criteria. Correlation analysis shows significant correlations between As and Cr, Cu, Ni, Pb, and Zn concentrations both before and after the YR diversion. However, no significant correlations were observed between heavy metal concentration and pH before the diversion, and no heavy metal concentration was correlated with salinity. The principal component analysis indicates that these trace elements, including As, were closely correlated with each other and therefore likely originated from shared pollution sources before the diversion. These results are useful for assessing the heavy metal contamination and proposing feasible suggestions to improve soil quality.  相似文献   

11.
In order to determine the characteristics of heavy metals’ pollution and identify their sources in the soil over the Xiaoqinling gold-mining region, Shaanxi, China, 133 soil samples were collected over the region, one sample was from a close point as background, and concentrations of Hg, Pb, Cu, and As in all samples were analyzed. Results indicated that the soil was polluted by these heavy metals, as their concentrations in the soil over the studied region were higher than that in the background zone. In addition, the result indicated that these metals had their specific spatial characteristics. Among the samples, those with higher concentrations of Hg, Pb, and Cu were mainly collected from the Shuangqiao river alluvial terrace area, the loess ravine tableland, and the piedmont alluvial–pluvial inclined tableland, which are the areas of gold-mining activities. Meanwhile, the samples with higher concentrations of As were distributed over the loess ravine tableland around Tongguan County, where agricultural activities were conducted intensively. Furthermore, the sources for all the heavy metals Hg, Pb, Cu, and As in the soil over each landscape were determined through analyzing the concentration correlation of these metals and comparing the maps of metal concentration distribution and land-use types. In Yellow river–Weihe river alluvial plain area, these heavy metals were mainly from agricultural activities. In the other landscapes, As was also mainly from agricultural activities; the other metals were contrarily from the gold-related activities. Interestingly, the correlation coefficients of As concentrations with Hg, Pb or Cu concentrations were positive in the samples from Yellow river–Weihe river alluvial plain area, and on the contrary, they were negative in the samples from the other landscapes. This result showed that the correlation can be used as an index to indicate properly the effect of the gold-related or agricultural activities on the heavy metals in the soil and identify their main sources over each landscape. As human activities resulted in the site-specific characteristics in the concentrations and sources of the heavy metals in each landscape, site-specific control strategies should be selected intensively to remedy landscape soil pollution. In Yellow river–Weihe river plain area, effective control strategies should be aimed at remedying As pollution caused by agricultural activities; in the other landscapes, Hg, Pb and Cu pollution caused by gold-mining activities should be considered.  相似文献   

12.
Abstract: The present study demonstrates distribution and chemical forms of heavy metals in soils of the Almalyk mining and smelting industrial area along five transects. The study area is located in Almalyk, Uzbekistan, where the intensification of industrial enterprises negatively impacts the environment. The distribution of 17 heavy metals (Cu, Zn, Pb, Sc, V, Cr, Co, Ni, Ga, Rb, Sr, Y, Zr, Nb, Ba, Th, and U) were studied in 21 sampling locations (21×3=63 soil samples) along five radial transects with a total length of 60?km downwind deposition gradient. Soil samples were collected from the upper layer (0–10?cm) at 4–6?km intervals. As a result of X-ray fluorescence spectrometry analyses by using X-ray fluorescence spectroscopy (XRF, Philips Analytical Ink, USA ), a significant decrease in heavy metal (Cu, Zn, Pb) deposition was found going from the source in a downwind direction. Soil samples taken from the first location (near the pollution sources) showed higher concentrations of Cu, Zn and Pb, and lower concentrations with increasing distance from the source. Obtained data showed different impact of pollution sources to heavy metal deposition and distribution in soils. The Almalyk mining and smelting complex is the major source of Pb, Zn and Cu enrichment in soils. Distribution of other trace elements does not exceed background content and suggests lithogenic background. This allowed us to divide these elements into two groups: (1) technogenic (Cu, Zn and Pb); and (2) lithogenic (Sc, V, Cr, Co, Ni, Ga, Rb, Sr, Y, Zr, Nb, Ba, Th and U) origins.  相似文献   

13.
High concentrations of heavy metal in farmland threatens food production and human health. Our study assesses soil quality and the distribution of Cd, Cr, Cu, Zn, Pb and Ni, to identify possible sources of heavy metals along the banks of the Yangtze River in Huangshi. Heavy metal concentrations of 22 topsoil samples were measured using the inductively coupled plasma mass spectrometry instrument and data was analyzed by multivariate statistic approaches. Heavy metal contamination risk assessment was performed using a combination of the Nemerow multi-factor index method, the Hakanson potential ecological risk index method and the Muller index of geo-accumulation method. These methods determined similar results indicating that cadmium (Cd) poses a health risk to residents at the study site while Cr, Cu, Zn, Pb and Ni do not. The Nemerow multi-factor index method demonstrated that 18 samples were heavily polluted, three moderately polluted and one lightly polluted. The Muller index of geo-accumulation method found ten samples were moderately to strongly polluted by Cd, five were moderately polluted, six were lightly to moderately polluted and one was lightly polluted. The Hakanson potential ecological risk index method proved six samples were strongly polluted, seven were moderately polluted and nine were lightly polluted. Since our sampling sites were all in agricultural lands, we recommend the potential ecological risk index method as the most effective given it not only considers the range of pollutants contributing to soil pollution but factors in heavy metals toxicity. We are apt that the source of the high concentrations of Cd found in topsoil is derived from alluvial sediments upstream of the Yangtze River with a high percentage of residual speciation and a low percentage of exchangeable speciation distribution of Cd. This in turns indicates that a high concentration of Cd in soil had little impact on the natural environment. However, 31.9% of the iron-manganese oxides bound speciation indicating that such levels of Cd in soil would be potentially hazardous to the crops, particularly if exposed to a reductive condition.  相似文献   

14.
Soil pollution in agricultural areas surrounding big cities is a major environmental problem. Tabriz is the largest city in the northwest of Iran and the fourth largest city in the country. Soil samples were taken from 46 sites in the suburbs of the Tabriz city, and separate samples were taken from control site and analyzed. The results indicated that the mean pH value of the soil samples was 9.29, while the mean EC value was 354.33 μs/cm and the amount of TOC and TOM was 0.99 and 1.7 %, respectively. The mean concentrations of Cd, Pb, Cu, Cr, Ni, and Zn in the soil were determined to be 1.61, 10.56, 101.25, 87.40, 38.73, and 98.27 mg/kg, respectively (dry weight). The concentrations of heavy metals (Cd, Pb, Cu, Cr, and Zn), with the exception of Ni, were higher than the concentrations of the same heavy metals at the control site. Despite these elevated concentrations, the concentrations of heavy metals were lower than the toxicity threshold limit of agricultural soils. The values of the pollution index revealed that the metal pollution level was Pb > Cr > Cu > Zn > Cd > Ni, and the mean value of the integrated pollution index was determined to be 1.81, indicating moderate pollution. Nevertheless, there were some sites that were severely polluted by Cr (maximum values of 1,364 mg/kg). It was concluded that city probably has affected the surrounding agricultural area. Application of wastewater (municipal and industrial) as irrigation water, using of sludge as soil fertilizer, and atmospheric perceptions have been considered as main reasons of increased heavy metals concentrations found in the studied area.  相似文献   

15.
The geochemical characteristics of trace metals (As, Cr, Co, Cd, Cu, Mn, Ni, Pb, V and Zn) in PM10 in Wuhan, the biggest metropolitan in central China, as well as their sources and contributions were analyzed. As PM10 has been the principal contaminant of air in Wuhan for years, concentrations of trace metals were measured in PM10 using high-volume samplers at one urban (Hankou) and one industrial (Changqian) site in Wuhan between September 2003 and September 2004. Based on the results, PM10 in Wuhan is characterized by relatively high levels of As, Cd, Mn, Pb and Zn compared with other Asian cities. The time-series of these elements indicated that As, Cu and Zn at both sites have similar trends, whereas Pb levels showed different patterns due to different emission sources. Factor analysis was applied to the datasets focusing on the apportionment of the mass of selected trace metals. Results indicate that Pb, Cd and As have a common source (smelting) at both sites, whereas the sources of Ni vary from coal combustion and steel in Changqian to mineral and traffic in Hankou.  相似文献   

16.
Manganese oxides from deposits in west-central Arkansas were analyzed by X-ray diffraction for mineralogy and by atomic absorption spectroscopy for Mn, Fe, Co, Cu, Ni, Zn, V, Al, Li, Na, K, Mg, Ca, Sr and Ba. We report on 42 samples from 25 sites with more than 25 wt.% Mn and less than 7 wt.% Fe. Most samples were mixtures of two or more of the following minerals, many with concentric deposition: cryptomelane, lithiophorite, psilomelane and pyrolusite. In the purer samples of single minerals, lithiophorite contained the higher concentrations of total base metals (Co + Cu + Ni + Zn) than other minerals. In atom % of Mn these concentrations were: 9.51% in lithiophorite; 0.432% in psilomelane; and 0.275% in cryptomelane. The relative concentration of base metals in the pure minerals, proceeding from highest to lowest concentration, were: lithiophorite (Co = Cu > Ni > Zn); psilomelane (Co > Cu > Zn > Ni) and cryptomelane (Zn > Co = Cu > Ni).The concentration of Li correlates with the metals Al, Co, Cu, Ni and Zn, in the mineral samples containing measurable Li. Correlation coefficients (?) for Li with the various metals and sum of the base metals were: Al (? = 0.976); Co (? = 0.44); Ni (? = 0.954); Cu (? = 0.918); Zn (? = 0.875); and (Co + Cu + Ni + Zn) (? = 0.979). Li is believed to be a measure of lithiophorite. Correlation was found between Al content and base metal contents for all samples: Co (? = 0.354); Ni (? = 0.749); Cu (? = 0.808); Zn (? = 0.632); and (Co + Cu + Ni + Zn) (? = 0.884). The Al correlation extended to published values for these and the minerals hollandite and todorokite, except for Zn. Zn correlated with K in published analyses and in the eastern half of the study area where cryptomelane predominated.A mechanism is proposed to explain the enhancement by Al of base metal incorporation into manganese oxide minerals. The mechanism involves the isomorphous substitution of Al3+ for Mn4+ with charge neutralization by bivalent base metal ions.  相似文献   

17.
《Applied Geochemistry》2001,16(7-8):759-780
A multi-medium, multi element regional geochemical survey has been carried out in an 188,000 km2 area in the Central Barents Region, Finland, Norway and Russia. Four different sample materials (terrestrial moss, O-, B- and C-horizons of podzol) were collected at the same sites throughout the area at a density of 1 site/300 km2. While moss predominantly reflects the atmospheric input of elements, the O-horizon reflects the complex interplay between atmosphere, biosphere and lithosphere. The B-horizon can be used to study the influence of soil-forming processes, while the C-horizon represents the composition of the lithosphere at each sample site and thus the geogenic background. The concentration, variation and correlation between 24 elements (Ag, Al, As, Ba, Bi, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, Sr, Th, V, Zn) analysed with similar techniques in all 4 materials are compared. Some rare trace elements (Ag, As, Bi, Cd, Pb) appear to be considerably more enriched in the O-horizon of podzols than the main pollutants in the survey area (Ni, Cu, Co from the Russian nickel industry in Monchegorsk and Nikel-Zapoljarnij). Biological processes play an underestimated role in determining regional geochemistry at the earth's surface.  相似文献   

18.
为探究云南省碳酸盐岩风化区重金属污染特征及分布影响因素,选取云南省宣威市农垦区为研究对象,利用1:5万土地质量地球化学调查成果,通过分析表层土壤重金属元素累积特征及分布规律,并结合土壤理化性质及地形因素等数据,研究驱动农垦区土壤重金属元素富集的影响因素,并利用富集指数法(EF)和潜在生态风险评价(RI)进行污染评价.结...  相似文献   

19.
《Applied Geochemistry》2000,15(4):513-530
Soil samples taken from excavated pits on traverses across New Zealand’s Scott Base, Antarctica, were leached with water and 0.01 M HNO3 and the leachates analysed for Ag, Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The soils had high conductivity and pH values generally increasing with depth and in the range 8.3–10.1. The water leachate generally contained most of the extractable metals except Mn and Cd, and As. Linear relationships were observed between some metals leached into alkaline solution and the Fe in those solutions. The ratios to Fe were comparable to those of the host basanite, and this observation is interpreted as showing that these metals are incorporated in fine mineral particulates derived directly from the rock mass. Outliers in leachable metal concentrations in the soils indicated appreciable contamination of the soil from anthropogenic sources with Ag, Cd, Cu, Pb and Zn as well as As. In some locations high concentrations of Ag and Cd correspond to specific sources and drainage channels. High concentrations of Pb were widely spread and in the top soil layers whereas the elevated concentrations of Zn were distributed throughout the soil profiles indicating atmospheric sources and different mobilities within the soils. Transport within the soils is evident for some metals, as is lateral movement over and through the soils.  相似文献   

20.
A study of agricultural lands around an abandoned Pb–Zn mine in a karst region was undertaken to (1) assess the distribution of heavy metals in the agricultural environment, in both dry land and paddy field; (2) discriminate between natural and anthropogenic contributions; and (3) identify possible sources of any pollution discovered. Ninety-two samples of cultivated soils were collected around the mine and analyzed for eight heavy metals, pH, fluoride (F?), cation exchange capacity, organic matter, and grain size. The eight heavy metals included Cd, Cr, Cu, Ni, Pb, Zn, As, and Hg. The average concentrations (mg/kg) obtained were as follows: Cd 16.76 ± 24.49, Cr 151.5 ± 18.24, Cu 54.28 ± 18.99, Ni 57.5 ± 14.43, Pb 2,576.2 ± 1,096, Zn 548.7 ± 4,112, As 29.1 ± 6.36, and Hg 1.586 ± 1.46. In a site where no impact from mining activities was detected, the mean and median of Cd, Cu, Ni, Pb, Zn, As, and Hg concentrations in investigated topsoils were higher than the mean and median of heavy metal concentrations in reference soils. An ensemble of basic and multivariate statistical analyses was performed to reduce the multidimensional space of variables and samples. Two main sets of heavy metals were revealed as indicators of natural and anthropogenic influences. The results of principal component analysis (PCA) and categorical PCA demonstrated that Cd, Cu, Pb, Zn, and Hg are indicators of anthropogenic pollution, whereas Cr, As and Ni concentrations are mainly associated with natural sources in the environment. The contamination from Pb–Zn mining operations, coupled with the special karst environment, was a key contributing factor to the spatial distribution of the eight heavy metals in the surrounding soil. The values of heavy metals in the soil samples suggested the necessity of conducting a rigorous assessment of the health and environmental risks posed by these residues and taking suitable remedial action as necessary.  相似文献   

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