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1.
The risk assessment of heavy‐metal contamination in soils requires knowledge of the controls of metal concentrations and speciation. We tested the relationship between soil properties (pH, CEC, Corg, oxide concentrations, texture) and land use (forest, grassland, arable) and the partitioning of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn among the seven fractions of a sequential extraction procedure in 146 A horizons from Slovakia. Using a cluster analysis, we identified 92 soils as representing background metal concentrations while the remaining 54 soils showed anthropogenic contamination. Among the background soils, forest soils had the lowest heavy‐metal concentrations except for Pb (highest), because of the shielding effect of the organic layer. Arable soils had the highest Cr, Cu, and Ni concentrations suggesting metal input with agrochemicals. Grassland soils had the highest Cd and Zn concentrations probably for geogenic reasons. Besides the parent material (highest metal concentrations in soils from carbonatic rock, lowest in quartz‐rich soils with sandy texture), pedogenic eluviation processes controlled metal concentrations with podzols showing depletion of most metals in E horizons. Partitioning among the seven fractions of the sequential extraction procedure was element‐specific. The pH was the overwhelming control of the contributions of the bioavailable fractions (fractions 1–4) of all metals and even influenced the contributions of Fe oxide‐associated metals (fractions 5 and 6) to total metal concentrations. For fractions 5 and 6, Fe concentrations in oxides were the most important control of contributions to total metal concentrations. After statistically separating the pH from land use, we found that the contributions of Cu in fractions 1–4 and of NH4NO3‐extractable Al, Cd, Pb, and Zn to total metal concentrations were significantly higher under forest than under grassland and in some cases arable use. Our results confirm that metal speciation in soils is mainly controlled by the pH. Furthermore, land use has a significant effect. 相似文献
2.
Soil/solution partitioning of trace metals (TM: Cd, Co, Cr, Cu, Ni, Sb, Pb and Zn) has been investigated in six French forest sites that have been subjected to TM atmospheric inputs. Soil profiles have been sampled and analysed for major soil properties, and CaCl2‐extractable and total metal content. Metal concentrations (expressed on a molar basis) in soil (total), in CaCl2 extracts and soil solution collected monthly from fresh soil by centrifugation, were in the order: Cr > Zn > Ni > Cu > Pb > Co > Sb > Cd , Zn > Cu > Pb = Ni > Co > Cd > Cr and Zn > Ni > Cu > Pb > Co > Cr > Cd > Sb , respectively. Metal extractability and solubility were predicted by using soil properties. Soil pH was the most significant property in predicting metal partitioning, but TM behaviour differed between acid and non‐acid soils. TM extractability was predicted significantly by soil pH for pH < 6, and by soil pH and Fe content for all soil conditions. Total metal concentration in soil solution was predicted well by soil pH and organic carbon content for Cd, Co, Cr, Ni and Zn, by Fe content for Cu, Cr, Ni, Pb and Sb and total soil metal content for Cu, Cr, Ni, Pb and Sb, with a better prediction for acidic conditions (pH < 6). At more alkaline pH conditions, solute concentrations of Cu, Cr, Sb and Pb were larger than predicted by the pH relationship, as a consequence of association with Fe colloids and complexing with dissolved organic carbon. Metal speciation in soil solutions determined by WHAM‐VI indicated that free metal ion (FMI) concentration was significantly related to soil pH for all pH conditions. The FMI concentrations of Cu and Zn were well predicted by pH alone, Pb by pH and Fe content and Cd, Co and Ni by soil pH and organic carbon content. Differences between soluble total metal and FMI concentrations were particularly large for pH < 6. This should be taken into account for risk and critical load assessment in the case of terrestrial ecosystems. 相似文献
3.
Trace elemental concentrations (Fe, Ni, Mn, Cr, Co, Cu, Zn, Pb, Cd, and As) in aerial biomass (stems, leaves, and flowers) of the medicinal plants Teucrium chamaedrys, T. montanum, and T. polium growing on serpentine soils in Bulgaria were examined in relation to the total element contents in their respective rhizospheric soils. The objectives of the study were to evaluate: (1) elemental concentrations in plant tissues and associated soil samples together with the plants ability to tolerate/accumulate metal concentrations; (2) correlations between total metal concentrations in plants and their rhizospheric soils. Metal concentrations varied across species and sites. Their levels in plant tissues from nonserpentine sites were always lower compared to those from serpentine ones. The highest concentrations for Fe, Ni, Mn, Cr, As, Cu, and Pb were found in T. polium. Positive correlation coefficients were established between Ni, Cr, Fe, Co, and Cu in plants and Ca in the soil. None of the species tested hyperaccumulated metals although the metal concentration in some of them exceeded the range naturally found in plants. The Teucrium species can be considered as “excluders”, containing relatively low metal concentrations in their aerial parts (stems, leaves, and flowers) even in cases of high elemental concentrations in the rhizospheric soil. In all three medicinal plants, metal concentrations for toxic elements were above the permissible limits for pharmaceutical purposes. Therefore, plants found on serpentine bedrock are not recommended to be collected for pharmaceutical purposes. 相似文献
4.
The objective of this study was to test the suitability of a simple approach to identify the direction from where airborne heavy metals reach the study area as indication of their sources. We examined the distribution of heavy metals in soil profiles and along differently exposed transects. Samples were taken from 10 soils derived from the same parent material along N-, S-, and SE-exposed transects at 0—10, 10—20, and 20—40 cm depth and analyzed for total Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn concentrations. The heavy metal concentrations at 0—10 cm were larger than background concentrations in German arable soils except for Cr (Cd: 0.6—1.8 mg kg—1; Cr: 39—67; Cu: 40—77; Ni: 87—156; Pb: 48—94; Zn: 71—129; Fe: 26—34 g kg—1; Mn: 1.1—2.4). Decreasing Cd, Cu, Mn, and Pb concentrations with increasing soil depth pointed at atmospheric inputs. Aluminum and Ni concentrations increased with soil depth. Those of Fe, Cr, and Zn did not change with depth indicating that inputs at most equalled leaching losses. The Pb accumulation in the surface layer (i.e. the ratio between the Pb concentrations at 0—10 to those at 20—40 cm depth) was most pronounced at N-exposed sites; Pb obviously reached Mount Križna mainly by long-range transport from N where several industrial agglomerations are located. Substantial Cd, Cu, and Mn accumulations at the S- and SE-exposed sites indicated local sources such as mining near to the study area which probably are also the reason for slight Cr and Zn accumulations in the SE-exposed soils. Based on a principal component analysis of the total concentrations in the topsoils four metal groups may be distinguished: 1. Cr, Ni, Zn; 2. Mn, Cd; 3. Pb (positive loading), Cu (negative loading); 4. Al, Fe, indicating common sources and distribution patterns. The results demonstrate that the spatial distribution of soil heavy metal concentrations can be used as indication of the location of pollution sources. 相似文献
5.
《Communications in Soil Science and Plant Analysis》2012,43(13-14):1975-1996
Abstract A study was carried out to investigate the status of four micronutrients, iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn), and five other trace elements, cobalt (Co), chromium (Cr), nickel (Ni), lead (Pb), and strontium (Sr), in paddy soils of Bangladesh. Soil samples were digested by hydrofluoric acid (HF)‐nitric acid (HNO3)‐perchloric acid (HClO4) for determination of total contents of the nine elements, while DTPA, ASI and 0.1 Mhydrochloric acid (HC1) methods were used for determination of available Fe, Cu, Mn, and Zn. Total trace element contents were found to vary with physiography on which soils are distributed. In general, Ganges Tidal Floodplain soils had the highest content, whereas terrace soils had the lower content. Among the soil properties examined, clay content had a good relation with total trace element contents in the topsoil, except for Sr. Based on the variation with physiography or clay content, the nine trace elements could be grouped into six groups: Cu, Fe and Zn, Pb, Co and Cr and Ni, Mn, Sr. According to the extractable levels of four micronutrients, Bangladesh paddy soils had the medium to optimum amounts of Fe and Cu, but were deficient sporadically in Mn and extensively in Zn. It was indicated that paddy soils of Bangladesh are yet to be polluted with heavy metals. 相似文献
6.
Heavy metal transport in Cauvery river chiefly takes place in the particulate form. Tributaries Hemevathi and Kabini draining highly mineralized areas contribute significantly to the heavy metal load of the Cauvery river. Particulate metal transport is influenced by the presence of major dams built across the river. Factor analysis of the elemental data identifies two major group of heavy metals, (a) Fe, Mn, Cr, V and Ti and (b) Cu, Pb and Zn in the suspended sediments of Cauvery river. Heavy metals in surface sediments show wide variations in their concentrations due to the non-uniform grain size distribution of the sediments. The elements Fe, Mn, Pb, Cu, Zn, Ni, Co and As are dominantly present in the <20 μm fraction of the river sediments. Speciation studies show that Fe-Mn oxide phase held the largest share of heavy metals in the sediments. The depth variation of heavy metals in the core sediments suggest their similar mobility during diagenesis. Geoaccumulation indices calculated suggest that Cd, Zn, Cr, Pb, Cu and Ni are enriched in sediments several times over background values. 相似文献
7.
复合污染土壤中水稻根际元素特性及效应研究 总被引：1，自引：1，他引：0
【目的】以广东大宝山重金属复合污染农田为生长介质,通过研究水稻不同部位生长量、 金属含量、 对金属的富集系数,及其与根际、 非根际土金属含量、 形态变化的相关关系,探讨根际效应可能对水稻体内金属积累转运以及生物量的影响。【方法】选取了广东大宝山稻田重金属复合污染(As、 Pb、 Fe、 Cu、 Zn)土壤及当地常见的20个水稻品种进行根际袋试验,即将根际袋内的土视为根际土,根际袋外的土视为非根际土,将供试水稻品种种植于根际袋土壤中60天后收获,测定水稻各部位的生长量、 不同金属的含量,根际土和非根际土中各金属有效态的含量。【结果】Fe、 Cu、 Pb、 Zn、 As在根部的富集系数均大于其在茎叶的富集系数,各金属在茎叶和根部的富集能力排序分别为Zn Cu As ≈ Pb ≈ Fe和Fe Zn As Cu Pb。根际土和非根际土中各种金属有效态含量均为Fe Cu Pb Zn As。研究还发现,有效态Fe、 Cu和Zn浓度对整株干重的影响显著,作用强弱顺序为Cu Zn Fe,对水稻生长影响作用显著的三种有效态金属Fe、 Cu和Zn均为植物生长所必需的元素。供试土壤中有效态Cu浓度对水稻的生长所起的作用最强。根际土有效态Fe浓度对根系Fe的积累作用效果显著,有效态As浓度显著抑制了根系Fe的积累,且有效态As浓度的作用强于有效态Fe。【结论】根际土中有效态Fe对株高、 根干重、 茎叶干重和整株干重均起着抑制作用,有效态Cu对水稻生长起到了促进作用。根际土有效态As和非根际土有效态Zn对根部Fe的积累起到了抑制作用,根际土有效态Fe和非根际土有效态Cu则起到了促进作用。非根际土有效态Fe和有效态Zn对水稻根长的增加均起到了促进作用。 相似文献
8.
Trace elements may present an environmental hazard in the vicinity of mining and smelting activities. However, the factors controlling their distribution and transfer within the soil and vegetation systems are not always well defined. Total concentrations of up to 15,195 mg . kg –1 As, 6,690 mg . kg–1 Cu, 24,820 mg . kg–1 Pb and 9,810 mg . kg–1 Zn in soils, and 62 mg . kg–1 As, 1,765 mg . kg–1 Cu, 280 mg . kg–1 Pb and 3,460 mg . kg –1 Zn in vegetation were measured. However, unusually for smelters and mines of a similar size, the elevated trace element concentrations in soils were found to be restricted to the immediate vicinity of the mines and smelters (maximum 2–3 km). Parent material, prevailing wind direction, and soil physical and chemical characteristics were found to correlate poorly with the restricted trace element distributions in soils. Hypotheses are given for this unusual distribution: (1) the contaminated soils were removed by erosion or (2) mines and smelters released large heavy particles that could not have been transported long distances. Analyses of the accumulation of trace elements in vegetation (median ratios: As 0.06, Cu 0.19, Pb 0.54 and Zn 1.07) and the percentage of total trace elements being DTPA extractable in soils (median percentages: As 0.06%, Cu 15%, Pb 7% and Zn 4%) indicated higher relative trace element mobility in soils with low total concentrations than in soils with elevated concentrations. 相似文献
9.
Adamo Paola Dudka S. Wilson M. J. McHardy W. J. 《Water, air, and soil pollution》2002,137(1-4):95-116
The sequential extraction procedure proposed by the European Commission Measurement and Testing Programme, combined with Scanning Electron Microscopy and Energy Dispersive X-ray Analysis(SEM/EDS), was applied to identify and quantify the chemical andmineralogical forms of Cu, Ni, Fe, Mn, Zn, Pb, Cr and Cd presentin the topsoil from a mining and smelting area near Sudbury (Ontario, Canada). The possible mobility of the chemical forms was also assessed. The metal fractions: (1) soluble and exchangeable, (2) occluded in manganese oxides and in easily reducible iron oxides, (3) organically bound and in form of sulphides, (4) residual mainly present in the mineral lattice structures were separated. Cu and Ni were the major metallic contaminants, occurring in soils in broad ranges of concentrations: Cu 11–1890 and Ni 23–2150 mg kg-1. Cu was uniformly distributed among allthe extracted fractions. Ni was found associated mainly withthe residual forms, accounting for 17–92%, with an averageof 64%, of the total Ni present in the soils. Fe, Mn, Zn,Pb, Cr and Cd, while occurring in most analysed samples innormal soil concentrations, were primarily held in theresidual mineral fraction (on average >50%). The solubleand exchangeable forms made a small contribution (≤8.1%)to the total content of metals extracted. At least 14% ofthe total Cd, Mn and Pb was mobilised from the reducibleforms. The oxidizable fraction assumed mean values higher than10% only for Pb and Zn. Statistical treatment of the experimental data showed significant correlations between totalmetal content of the soils, some soil properties such as pH value, clay and organic matter content, and metal concentrationsin the various fractions. SEM/EDS analysis showed Fe in form ofoxides and sulphides in soils and Cu, Ni, Mn, Zn and Cr in association with iron oxides. Numerous black carbonaceous particles and precipitates of aluminium fluoride salts, observedin the solid residue left after `total’ digestion, were found tocontain Fe, Ni and Cr. 相似文献
10.
Along a heavy metal deposition gradient, caused by a Cu smelter, heavy metal concentrations, partitioning, and storage in forest and arable soils were examined. We sampled organic and mineral soil horizons (0—50 cm) at ten pairs of forest and arable sites derived from the same parent material. A-horizons were extracted with a seven-step sequence; O- and subsoil horizons were digested with strong acids (HNO3/HClO4). We found high concentrations of Cd (up to 17.38 mg kg—1 in the O horizons/up to 2.44 mg kg—1 in the A horizons), Cu (8437/415), Pb (3343/126), and Zn (1482/637) which decreased exponentially with distance from the smelter and with soil depth. The metal concentrations in the organic layers indicate that the average transport distance decreases in the order Cd > Zn > Pb > Cu. With regard to metal partitioning, NH4NO3- + NH4OAc-extractable forms in the A horizons were most affected by the deposition being more pronounced under forest. In the uppermost 50 cm of the four soils nearest to the smelter two to four times higher Cd, Cu, Pb, and Zn storages were found in forest than in arable soils. At greater distance, the higher deposition onto forest soils due to the scavenging effect of the canopy obviously was compensated by stronger leaching. 相似文献
11.
Andres Rodríguez‐Seijo Maria C. Alfaya María Luisa Andrade Flora A. Vega 《Land Degradation \u0026amp; Development》2016,27(7):1721-1730
Small‐arms firing ranges are an important source of metal contaminants in the ecosystems located near these facilities, owing to the constant fall and alteration of the ammunition remnants on the soil, particularly in nearby berms. The objectives of this study were to analyse the pollution of chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in rifle/pistol shooting range soils, to estimate their availability and to evaluate the influence of the ammunition used. The concentrations of Pb, Zn, Cu, Cr and Ni range from 55 to 6·309, 34 to 264, 19 to 98, 40 to 79 and 11 to 33 mg kg−1, respectively. The moderate acidity and organic matter content favour the availability of Pb, followed by Cu > Zn > Ni > Cr. The values of different contamination indexes (Igeo, pollution index and integrated pollution index) suggest that Pb soil contamination is moderate to heavy, especially in the berm area and moderate for Cu and Zn. Lead ammunition is the main source of pollution, but another one was identified owing to the concentrations of Fe, Cr and Ni detected. Further studies are needed to verify their long‐term potential adverse effects. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
我国几种土壤中铁锰结核的元素组成和地球化学特点 总被引：7，自引：0，他引：7
The objective of this research was to isolate a dichlorvos （2,2-dichlorovinyl dimethyl phosphate）-degrading strain of Ochrobactrum sp., and determine its effectiveness in remediation of a dichlorvos-contaminated soil. A dichlorvos-degrading bacterium （strain DDV-1） was successfully isolated and identified as an Ochrobactrum sp. based on its 16S rDNA sequence analysis. Strain DDV-1 was able to utilize dichlorvos as a sole carbon source, and the optimal pH and temperature for its cell growth and degradation were 7.0 and 30 ℃, respectively. Also, the growth and degradation of strain DDV-1 showed the same response to dissolved oxygen. In addition, the soil degradation test indicated that in soil spiked with 100 mg L^-1 or 500 mg L^-1 dichlorvos and inoculated with 0.5% or 1.0% （v/v） strain DDV-1, complete degradation of dichlorvos could be achieved in 24 h. The present study showed that strain DDV-1 was a fast dichlorvos-degrading bacterium in soil. However, further research will be needed to clarify the degradation pathway and the properties of the key enzymes involved in its biodegradation. 相似文献
13.
Total content of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Co in soils irrigated with sewage effluent increased with increasing years of using sewage effluent in irrigation. Iron and Co applied to the soil from sewage effluent were immobilized mainly in unavailable form; Pb, Cd, and Ni in moderately available form; and Mn, Zn, and Cu in highly available form. The concentrations of Fe, Mn, Zn and Cu in tops of alfalfa and leaves of corn grown on these soils increased substantially with increased levels of available metal content of the soil, while those of other metals were little affected. As for orange, continuous increase in leaves metal content with time was found for Fe, Mn, Zn, Co and Cd. The concentrations of Cd, Co, Ni and Pb in corn grains and orange fruits were several times higher than normal, and this reduces their suitability for human consumption. 相似文献
14.
The history of heavy metal pollution in southern Sydney was reconstructed from wetland sediments using chemical analysis. Seven wetlands along the Pacific coast were examined for present day concentrations of acid-extractable Cd, Cu, Fe, Pb and Zn. Additionally, four of these sites were cored in order to assess past levels of these metal contaminants, changes in organic content and magnetic susceptibility variations. The low nutrient status and closed catchments of the study sites suggested that the pollutants were predominantly derived from atmospheric sources. Surficial sediments were enriched with Cd, Cu, Fe, Pb and Zn levels 5.0, 16.4, 22.7, 8.2 and 22.5 times baseline levels, respectively. In some cases, the concentrations of trace metals were in excess of environmentally acceptable levels. The results show a strong spatial association between sources and levels of pollutants, and the increase in metals levels in sedimentary records corresponds well to documentary historical evidence.This study demonstrates the utility of coastal wetlands in the reconstruction of atmospheric pollution histories, and their particular vulnerability to contamination from airborne pollutants in urban areas. 相似文献
15.
Road-deposited sediment, soil and precipitation (RDS) in Bratislava, Slovakia: compositional and spatial assessment of contamination 总被引：2，自引：1，他引：2
Katrina Krčmová Davina Robertson Veronika Cvečková Stanislav Rapant 《Journal of Soils and Sediments》2009,9(4):304-316
Background, aim and scope The urban environment in Bratislava is, in association with rapid urbanisation and industrialisation, significantly influenced
by several potential sources of pollution, including automobile exhaust and industry emmissions. Urban road-deposited sediments
contain many potentially toxic elements such as Pb, Cr, Cu, Zn and also Fe at concentrations much higher than in soil. In
this study, the chemical composition and spatial variability of road-deposited sediments in urban area of Bratislava were
assessed for the elements As, Cd, Cr, Cu, Hg, Ni, Pb, Fe and Mn. Additional evaluation of archive data for soil, snow and
atmospheric dust was undertaken to provide an integrated view on urban environment contamination.
Materials and methods Urban road-deposited sediments (RDS) were collected during summer 2003 and 2004 mainly from major city crossroads. RDS samples
were analysed for total metal content, pseudo-total metal content (HNO3 digestion) and by a sequential extraction method, grain fraction composition and mineralogical composition (X-ray analysis).
Metal concentrations in soil and snow samples from urban and non urban city area were compared.
Results and discussion The highest concentrations for all metals were found in the finest RDS fraction (<0.125 mm). Whilst in the fraction <1 mm
mean concentrations of Cr, Cu and Pb reached 55.2, 143.8 and 34.4 mg kg−1, respectively, for the fraction <0.125 mm, markedly higher contents of these elements were documented at the level of 86.8,
218.4 and 63.1 mg kg−1, respectively. The soil contents of potentially toxic risk elements in the urban area including As, Cr, Cu, Fe, Hg, Mn, Ni,
Pb and Zn were higher than in the non-urban area (except for Cd with similar contents). This distribution pattern of evaluated
chemicals in urban and non-urban area is more evident in the case of winter precipitation (snow). The snow concentrations
of As, Cr, Cu, Fe, Mn, Pb and Zn in the urban area were two tot five times higher than in non-urban area.
Conclusions and recommendations Monitoring of road-deposited sediments, dust, soil and precipitation has confirmed the significant contamination of the urban
environment in Bratislava with potentially toxic elements that can pose a threat for the health of its residents. Future works
should be based on analyses of temporal variability of RDS and analyses of organic matter content. 相似文献
16.
U. K. P. S. Sanjeevani R. Weerasooriya U. W. A. Vitharana D. Kumaragamage 《Communications in Soil Science and Plant Analysis》2017,48(8):865-877
Elevated concentrations of potentially toxic trace elements in agricultural soils contribute to soil pollution affecting food quality and safety. We assessed pollution levels in agricultural systems, lowland rice (LL) and highland cash crops (HL), by comparing with non-agricultural soils (NA). Correlation analysis and principal component analysis (PCA) were performed, and geo-accumulation index (Igeo) and pollution loading index (PLI) were calculated. Zinc in LL, and Cd in LL and HL, were significantly higher than in NA. The Igeo values of cooper (Cu), lead (Pb), nickel (Ni), zinc (Zn), and cadmium (Cd) ranged from uncontaminated to moderately contaminated (Class 0 to 2) for LL, HL, and NA. Overall, trace element levels were categorized as unpolluted based on PLI. Soil properties significantly correlated with Cu, Pb, Ni, and Zn concentrations but not with Cd. Based on PCA, sources of origin for Cu, Pb, Ni, and Zn were lithogenic, while the sources for Cd was anthropogenic in the studied agricultural soils. 相似文献
17.
The Nature and Distribution of Metals in Soils of the Sydney Estuary Catchment, Australia 总被引：1，自引：0，他引：1
Gavin F. Birch Matthew Vanderhayden Marco Olmos 《Water, air, and soil pollution》2011,216(1-4):581-604
Total topsoil 50th percentile Cu, Pb and Zn concentrations (n?=?491) in the Sydney estuary catchment were 23 ??g?g?1, 60 ??g?g?1 and 108 ??g?g?1, respectively. Nine percent, 6% and 25% of samples were above soil quality guidelines, respectively and mean enrichment was 14, 35 and 29 times above background, respectively. Soils in the south-eastern region of the catchment exhibited highest metal concentrations. The close relationship between soil metal and road network distributions and outcomes of vehicular emissions modelling, strongly suggested vehicular traffic was the primary source of metals to catchment soils. Catchment soil and road dust probably make an important contribution to contamination of the adjacent estuary. The concentration of soil metals followed the land use trend: industrial?>?urban?>?undeveloped areas. A high proportion (mean 45%, 62% and 42%, for Cu, Pb and Zn, respectively) of metals in the soils may be bioavailable. 相似文献
18.
《Communications in Soil Science and Plant Analysis》2012,43(8):1028-1041
The bioavailability and mobility of heavy metals in soil are strongly influenced by the chemical or geochemical species of the metals in soils. We determined the geochemical fractions of copper (Cu), lead (Pb), and zinc (Zn) in garden soils, using the seven-step Zeien and Bruemmer fractionation scheme in relation to metal uptake by two leaf vegetables (lettuce, Latuca sativa, and amaranthus, Amaranthus caudatus). Our objective was to develop predictive models for assessing the lability of these metals from the soil metal fractions. The sums of fractions of Cu, Pb, and Zn did not differ by more than 10% from the “pseudo” total concentrations of the metals determined independently by aqua regia digestion. The general distribution of Cu and Pb among the soil fractions was in the order organic-matter-bound > Feo and Fec > Mnox > exchangeable > residual > mobile, except for Cu, where residual and the exchangeable were reversed. Zinc was fairly evenly distributed among organic matter (20%), Feo (22%), Fec (20%), and residual (21%). Averaged across sites, Cu, Pb, and Zn concentrations in the lettuce were almost twice as great as the concentrations in amaranthus even though they were raised in the same fields. The variance in Cu, Pb, and Zn uptake by amaranthus was predicted up to 51–99% from soluble, exchangeable, organic matter, and Feo-bound fractions; the variance in metal uptake by lettuce was best predicted from Fec- and Feo-bound fractions up to 76–90%. Our results indicated differential accessibility to metal fractions by lettuce and amaranthus grown in the same field. 相似文献
19.
The discharge of acidic mine drainage waters onto a hillslope in Dalarna, central Sweden, has lead to the contamination of the podzol soils with Cu, Fe, Ni, Pb, Zn and sulfate. Samples from contaminated and reference soils have been collected for chemical and mineralogical analyses. Jarosite is identified by x-ray diffraction analysis as a precipitate in the upper horizons (A, E, B) of the contaminated soils, where the soil acidity (pHKCl～2.6) promotes jarosite stability. The sequential chemical extraction of soil samples indicates that, in the reference A horizon, Cu, Pb, Ni and Zn are bound primarily to cation exchange sites and organic matter. In the A horizon of the contaminated soils closest to the rock dump, metal partitioning is dominated by the Fe oxide fractions, despite the high organic matter content; Pb is almost completely bound to crystalline Fe oxides, possibly adsorbed to Fe oxides or occuring in a jarosite solid solution. In the reference B and C horizons, Cu, Ni and Zn are primarily adsorbed/coprecipitated in the Fe oxide fractions, while Pb remains with a large fraction bound to organic matter. In the Fe-rich B horizon of the contaminated soils, the partitioning of the metals in cation exchange sites and to organic matter has greatly increased relative to the reference soils, resulting from the mobilization of organo-metal complexes down the profile. 相似文献
20.
We present the concentrations and distribution patterns of nine acid leachable trace metals (ALTMs) Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, and Cd in the soil samples from the five century old Pachuca-Mineral de Monte mining district of the Central Mexico. The ALTMs do not show any significant correlation with pH, EC, CaCO3, and organic carbon. The metal concentration indicates three distinct distribution patterns. Fe, Mn, Cr, Pb, and Zn show enrichment in the high altitude region of the northern and central part of the study area. Likewise, Cu and Cd are enriched in the northern mountainous terrains. Both these groups show strong positive correlation with Mn indicating that they are associated with Mn-bearing minerals. However, we relate the first group of metals to excessive vehicular transportation and second group to mining waste dumps. The third group of ALTMs Co and Ni indicates its direct relationship to ore processing activities. Comparison of ALTMs concentrations from this study and various other studies throughout the world suggests the need to take precautionary measures of surface soil in high altitude areas to avoid metal enrichments and its subsequent environmental problems. 相似文献