Fractional composition of lead compounds in soils of Moscow and Moscow region

Sequential fractionation of lead compounds from the urban and suburban soils of Moscow and eastern Moscow region was performed using the Tessier method. It was found that strongly bound lead compounds retained by Fe and Mn hydroxides were predominant in the background (reference) soils of the Meshchera Lowland in Moscow oblast. The content of almost all the lead fractions, except for the hydroxide fraction, increased in the contaminated soils. The quantitative proportions of the particulate fractions varied depending on the distance from the city, the physicochemical properties of the soils, and the land use. The profile distribution of the lead was of accumulative character; the metal was fixed on the biogeochemical barrier, where the lead compounds of the fourth fraction bound to organic matter are mainly accumulated.     

Fractional composition of nickel,copper, zinc,and lead compounds in soils polluted by oxides and soluble metal salts

The transformation of technogenic compounds of nickel, copper, zinc, and lead entering the soil as nitrates and oxides has been studied in a model experiment. It has been shown that the results of the determination of the fractional composition of the heavy metals strongly depend on the fractionating method used. The fractional composition of heavy metals that entered the soil as the readily soluble compounds mainly depends on the affinity of ions with the reaction centers of the soil components. When soils are polluted by such weakly soluble compounds of heavy metals as oxides, their transformation and, consequently, the fractional composition formed are determined, in the first place, by the solubility of these compounds and only afterwards by the interaction of the products of the dissolution with the soil. The transformation of the technogenictechnogenic zinc and lead oxides in the soils is more complete than that of copper and nickel oxides. This leads to a strong increase in the portion of the residual fraction of these elements under fractionating. The 1 N nitric acid almost does not extract copper and nickel oxides from the soil. This can be a reason for the erroneous estimation of the extent of soil pollution.     

Fractional and group composition of the Mn, Cr, Ni, and Cd compounds in the soils of technogenic landscapes in the impact zone of the Novocherkassk Power Station

The compounds of Cr, Ni, Mn, and Cd in the soils around the Novocherkassk Power Station and the influence of the technogenic and natural factors on their composition were investigated. The data on the fractional and the group composition of these compounds proved to be informative for assessing the ecological state of the soils. The soil components specifying the accumulation and the properties of the heavy metal compounds in the polluted and unpolluted areas were identified.     

Arsenic, lead, and zinc compounds in contaminated soils according to EXAFS spectroscopic data: A review

The application of the synchrotron technique of the third generation in soil science has permitted researchers to perform a quantitative mineralogical microanalysis in undisturbed samples and to reveal the relationship between the microelements and the solid phase of soils. Three principal methods are used in this technique: microfluorescence (μXRF), microdiffraction (μXRD), and the expanded analysis of the fine structure of the adsorption spectra. By the data of EXAFS spectroscopy, secondary arsenic was found to occur in three forms in soils, i.e., As adsorbed on iron hydroxides, scorodite (FeAsO₄ · 2H₂O, and As⁵⁺ containing jarosite. Despite the high share of carboxyl groups in the organic substance of soils, lead is more readily chelated by the functional groups of aromatic rings to form bidentant complexes. Lead phosphates are the most stable form of Pb in soils. One of the phosphates, i.e., pyromorphite Pb₅(PO₄)₃Cl has been found in ore tailings, lawn soils, soils near some chemical plants, and in soils within geochemical anomalies. The secondary Zn compounds are represented by Zn-containing silicate (kerolith) Si₄Zn₃O₁₀(OH)₂ and, to a lesser extent, by zinc fixed by manganese oxides (birnessite) and iron hydroxides (feroxyhyte).     

Fractional composition of redox systems in the soils of coal mine dumps

Specific features of the development of redox systems in the soils of coal mine dumps in Kemerovo oblast were studied. The quantitative characteristics of the fractional composition of the oxidized and reduced components in these soils were obtained, and their heterogeneity was shown. Distribution patterns of the reduced and oxidized components in the parent material of these specific technogenic landscapes in the course of soil evolution were revealed.     

The zinc status of some Nova Scotia soils and crops

Abstract

Ranges for total, 0.1N HCl and EDTA‐(NH₄)₂CO₃ extractable Zn in 69 samples of surface soil (0–15 cm), representing nine soil series, were 14–108, 0.9–10.5 and 0.5–8.0 ppm respectively. Total Zn in barley (Hordeum vulgare), carrot (Daucus carata sativa), corn (Zea mays L), grape (Vitis spp.), onion (Allium cepa), pea (Pisum sativum, strawberry (Fragaria spp.), and wheat (Triticum spp.) leaves and in barley and wheat grain ranged from 13.5 to 80.6 ppm.

The results suggest that, with the possible exception of corn leaf samples from one location, Zn levels in plant tissue were adequate. However, the results also indicate that liming strongly acid sandy soils reduces Zn availability and may induce a deficiency in Zn sensitive crops.     

Leaching of zinc,lead and cadmium in columns of calcareous soils

Leaching of zinc, lead and cadmium was studied in columns packed with soil differing in pH, clay, organic matter and calcium carbonate contents. Distribution of 1 N HCI extractable heavy metals in different layers of the columns as a function of the amount of water leached was the criteria for measuring leachability of the three metals. Leachates contained only traces of the metals. Movement of surface applied metals could be observed only upto 30mm depth. Cadmium, which was observed to be the most mobile element, was leached to a depth of 30–40mm in a pH 7.5, light textured soil with 0.9 % calcium carbonate. Presence of superphosphate at the soil surface reduced the extent of leaching to an appreciable extent.     

Evaluating soil microbial biomass carbon as an indicator of long-term environmental change

The aim is to assess whether soil microbial biomass carbon (biomass C) could be used as an indicator of environmental change in natural and semi-natural ecosystems. Biomass C was measured by fumigation-extraction in soils from two sites at Rothamsted. One was a plot from the Broadbalk Wheat Experiment, given inorganic fertiliser and chalk, which has been in continuous cultivation for more than 150 yr. The other was a similar sized area, from Geescroft Wilderness, which has been left to revert to woodland since 1885, after being an arable field. Other soil properties (pH, soil organic C and exchangeable cations) were also measured to compare with biomass C. The coefficients of variation (cvs) of the properties measured were calculated for comparison, little difference was found between the cvs for biomass C from each site: cv=26% for Broadbalk and 23% for Geescroft. The cvs for the other, chemical properties, were mostly <10% for Broadbalk and generally >25% for Geescroft, as expected, given the different cultivation histories. Statistical analysis of the variation in biomass C concentration revealed that such measurements would not be valid indicators of environmental change, without processing impossibly large numbers of samples. To decrease the least significant percentage change to less than 5% after three samplings, 320 samples would have to be taken each time. This would be also be true of the other chemical properties in Geescroft Wilderness, where the measured background variation would mask any subtle environmental change. This indicates that, for some properties at least, statistically significant changes will only be detected in the longer term with regular sampling, e.g. 30-40 yr.     

苏锡常地区城市公园土壤微量元素分布特征及其环境指示意义

在江苏省国土1/250 000多目标地球化学调查基础上,选择苏州市、吴江市、无锡市、江阴市、常州市、金坛市等45个城市公园土壤作为研究对象,系统研究了当地典型城市公园土壤中Cd、Hg、Pb、Zn、Sb、Sn、B、Se、N、稀土元素(REE)等50个元素含量及土壤pH、总有机碳(TOC)等分布特征。结果表明,城市公园土壤的微量元素分布与城区污染土壤、农田土壤有显著差异,公园土壤的重金属含量总体偏低、N与TOC含量明显低于农田土壤,在公园土壤中S、Se、Cd、Pb、Zn、TOC等元素未出现高强度的人为富集,重金属污染以轻度Hg污染为主,S、Se、Cd、Pb、TOC、pH等指标在200 cm深度内分布相对稳定、未出现元素含量在不同深度的显著变化,指示多数公园土壤的微量元素分布总体上较一般城市土壤更少受人为因素干扰,可为人为活动对城市土壤环境的影响研究提供重要的参比对象。     

Arbuscular mycorrhizal abundance in contaminated soils around a zinc and lead deposit

In order to study the variations in spore abundance and root colonization parameters of arbuscular mycorrhizal (AM) fungi in a naturally heavy metals polluted site and their relationships with soil properties, 35 plots in the Anguran Zn and Pb mining region were selected along a transect from the mine to 4500 m away. Within each plot, a composite sample of root and rhizospheric soil from a dominant indigenous plant was collected. The soil samples were analyzed for their physico-chemical characteristics. Spores were extracted, counted and identified at genus level. The roots were examined for colonization, arbuscular abundance, mycorrhizal frequency and intensity. Along the transect, the total and available (DTPA-extractable) concentration of Zn decreased from 6472 to 45 mg kg⁻¹ and 75 to 5 mg kg⁻¹, respectively. For Pb the values varied from 5203 to 0 mg kg⁻¹ and 32 to 0 mg kg⁻¹, respectively. In parallel, root colonization rate in the dominant native plants (except Alyssum sp.) varied from 35% to 85% and the spore numbers from 80 to 1306 per 200 g dry soil along the transect. Spores of Glomus were abundantly found in all plots as dominant, while Acaulospora spores were observed only in some moderately polluted and in control plots. AM fungal propagules never disappeared completely even in soils with the highest rates of both heavy metals. Spore numbers were more affected by Zn and Pb concentrations than root colonization. The variations of AM fungi propagules were better related to available than to total concentration of both metals. Spore numbers were positively correlated with mycorrhizal colonization parameters, particularly with arbuscular abundance.     

Speciation of cadmium,copper, lead,and zinc in contaminated soils

Abstract

To investigate the activity of free cadmium (Cd²⁺), copper (Cu²⁺), lead (Pb²⁺), and zinc (Zn²⁺) ions and analyze their dependence on pH and other soil properties, ten contaminated soils were sampled and analyzed for total contents of Cd, Cu, Pb, and Zn (Cd_T, Cu_T, Pb_T, and Zn_T, respectively), 0.43 MHNO₃‐extractable Cd, Cu, Pb, and Zn (Cd_N, Cu_N, Pb_N, and Zn_N, respectively), pH, dissolved organic matter (DOC), cation exchange capacity (CEC), ammonium oxalate extractable aluminum (Al) and iron (Fe), and dissolved calcium [Ca²⁺]. The activity of free Pb²⁺, Cd²⁺, Cu²⁺, and Zn²⁺ ions in soil solutions was determined using Donnan equilibrium/graphite furnace atomic absorption (DE/GFAA). The solubility of Cd in soils varied from 0.16 to 0.94 μg L^‐1, Cu from 3.43 to 7.42 μg L^‐1, Pb from 1.23 to 5.8 μg L^‐1, and Zn from 24.5 to 34.3 μg L^‐. In saturation soil extracts, the activity of free Cd²⁺ ions constituted 42 to 82% of the dissolved fraction, for Cu²⁺the range was 0.1 to 7.8%, for Pb²⁺ 0.1 to 5.1% and for Zn²⁺2 to 72%. The principal species of Cd, Cu, Pb, and Zn in the soil solution is free metal ions and hydrolyzed ions. Soil pH displayed a pronounced effect on the activity of free Cd²⁺, Cu^2t, Pb²⁺, and Zn²⁺ ions.     

A rapid method of evaluating the zinc status of coastal plain soils

Abstract

A study was made to evaluate Zn removed by extraction with a 0.075 N acid mixture (0.05 N HCl + 0.025 N H₂SO₄). A ratio of soil to extracting solution of 1 to 4 and an extracting time of 15 minutes was selected. Data obtained by the method was significantly correlated with dithizone (0.01%) extraction. The method was found to be acceptable for evaluation of the Zn status of Southern Coastal Plain soils and easily adapted to routine use in soil testing. A significant correlation was obtained between extractable soil Zn and leaf blade content of Zn for Zn‐deficient and non‐deficient corn plants.     

Effect of soil microorganisms on the sorption of zinc and lead compounds by goethite

The objectives of this study were (1) to determine the effect of microorganisms during in‐vitro incubation on the amount of Zn and Pb from solution retained on goethite precipitated as coatings on a sand matrix and (2) to evaluate accumulation of heavy metals in the biomass of soil microorganisms in the fresh soil samples using an extractive approach. A mixture of colonies of cultivated microorganisms extracted from a Haplic Luvisol (Russia) and an Antropi‐urbic Regosol (Germany) were used to prepare the cell and the microbial‐debris suspensions. The concentrations of Zn and Pb in the studied solutions supplied with microbial suspensions and/or goethite coated sand were 0.1 mM (130.8 and 414 mg kg^–1 of sand, respectively). Exchangeable forms of metals were determined by extraction with 10 mL of 1.0 M KNO₃. Nonexchangeable forms of Zn and Pb were recovered using 40 mL of 0.3 M NH₂OH‐HCl in 1 M HNO₃. Concentrations of Pb increased in the solutions and decreased on the surface of the Fe‐mineral due to living microorganisms. In comparison to incubation of heavy‐metal solutions with goethite only, the absolute concentrations of nonexchangeable forms of metal were reduced by microbial suspension to a greater extent than those of the exchangeable forms, whereas the relative content of both fractions decreased by a factor of almost two. Sorption of Pb by goethite was inversely correlated with the concentration of organic C in the solution. Microorganisms clearly influenced the Zn sorption by goethite at concentrations of C_org > 400 mg L^–1. The amount of Zn retained was decreased primarily due to decreasing Zn portions in the exchangeable fraction. Microbial debris prepared by autoclaving reduced the Pb sorption by goethite similar to the results for living cells. Living microorganisms accumulated more Zn than did microbial debris. The data of this paper show that a direct determination of heavy‐metal accumulation in soil microorganisms by extraction with 2.0 M KCl as well as by extraction with 1 M CH₃COONH₄ at the natural pH of the soils after chloroform fumigation of fresh soils samples with different concentrations of organic C was not possible.     

Mobile aluminum compounds in soils of the southern taiga (soils of the central forest reserve as an example)

The profile distributions of aluminum extracted by the Tamm and Bascomb reagents and of the exchangeable aluminum were studied in soils of automorphic, transitive, and accumulative positions in the landscapes of the southern taiga. In the mineral horizons of the gleyic peaty-podzolic soils developed on poorly drained flat surfaces and in the floodplain soils, the distribution of oxalate- and pyrophosphate-soluble aluminum has a strongly pronounced accumulative character. In the podzolic soils of the automorphic positions and slopes, an eluvial-illuvial distribution was characteristic with the maximal aluminum content in the podzolic horizons. The strong differentiation of the upper part of the profile in the automorphic podzolic soils in terms of the Al content in the Tamm and Bascomb extracts is mainly related to an increase of the pedogenic chlorite content upon the transition from the AE to the E horizon. In the podzolic horizons of these soils, aluminum can accumulate in the form of proto-imogolite structures. The exchangeable aluminum displays an accumulative type of distribution. On the basis of calculating the reserves of the different aluminum compounds, two main accumulative zones for the mobile compounds of this element were recorded in the soils of the landscapes studied: the E horizon in the automorphic podzolic soils, where Al accumulates as soil chlorite or, probably, as proto-imogolite, and the A1 horizon of the floodplain soils, where Al accumulates in aluminoorganic complexes.     

接种微生物对土壤中Cd、Pb、Zn生物有效性的影响

针对提高植物修复土壤重金属污染的效果,以印度芥菜作为重金属富集植物,通过盆栽试验研究了巨大芽胞杆菌和胶质芽胞杆菌的混合微生物制剂(A处理)和黑曲霉发酵液(B处理)对植物修复Cd、Pb、Zn污染土壤的作用效果。结果表明:巨大芽胞杆菌和胶质芽胞杆菌的混合微生物制剂,不仅可以促进富集植物的生长,使其印度芥菜的生物量提高24.73%,并且可促进土壤Cd、Pb、Zn的活化,使土壤Cd、Pb、Zn有效态含量分别提高15.02%、7.65%和2.23%,增强富集植物对土壤的Cd、Pb、Zn富集吸收,使印度芥菜对土壤Cd、Pb、Zn的提取量分别提高52%、121%和23%,显著提高其植物修复效果。从对植物生理生化指标的影响来看,A处理对植株的伤害程度要低于B处理,它是一种有助于植物修复Cd、Pb、Zn污染土壤的微生物制剂,在植物修复领域有较高的利用价值。然而,黑曲霉混合发酵液不适于促进植物修复应用。     

Arion ater (mollusca: pulmonata) as an indicator of terrestrial environmental pollution

Using X-ray energy spectroscopy concentrations of Mn, Fe, Cu, Zn, As, Br, Ph, Rb, and Sr were measured in specimens of the terrestrial gastropod, Arion ater, found in locations close to and far from a highway. Higher values of Pb and Br were observed for specimens near the polluting source and mathematical analysis revealed an inverse relationship between lead uptake and uptake of Cu, Zn, and Sr. The data are used to demonstrate a classification procedure in which trace metal concentrations in Arion ater are used to assess environmental quality.     

Kinetics of speciation of copper,lead, and zinc loaded to soils that differ in cation exchanger composition at low moisture content

Abstract

A better understanding of the fates of heavy metals in wide range of soils is important in improving efficiency of remediation technologies of heavy metals polluted soils. To contribute to this field we studied the kinetics of speciation of copper (Cu), leaf (Pb), and zinc (Zn) in six soils differed in major cation exchanger composition. Soluble salts of Cu, Pb, and Zn were loaded to the soils, incubated at field moisture contents, and the change in chemical forms of the metals was traced by sequential extraction. In Inceptisols predominated by 2:1 layer silicates and poorly crystalline iron oxides, the added Cu and Pb were found mostly in exchangeable and oxide bound fractions, with decreasing and increasing proportion of the former and the latter during 50 days after addition, respectively. In allophanic and humic Andisols, about 50 to 70% of the total Cu and Pb was found in oxide bound fraction with a significant amount in organically complexed fraction in the latter. The amounts of Cu and Pb in each fraction varied only slightly with time in these soils. The proportion of oxide bound Cu arid Pb was relatively low in a kaolinitic Ultisol irrespective of its higher iron oxide content. Zinc was found mostly in exchangeable and soluble fractions except in Andisols. Low crystallinity of oxide minerals as well as their amount is important factors determining heavy metal retaining capacity of soils. The exchangeable and oxide bound heavy metals should be treated separately in models simulating removal of heavy metal cations by washing and electrokinetic methods.     

Radish as an indicator plant for derelict land: Uptake of zinc at toxic concentrations

Abstract

Radish was grown in glasshouse experiments. Two experiments involved mixing varying ratios of calcareous zinc (Zn) mine waste with soil and in the third, radish was grown in culture solution supplemented with Zn. Zinc toxicity was seen at higher treatment concentrations. From curves for substrate Zn versus % yield the toxic threshold was estimated as 343 μg Zn/g soil which compares favourably with the British “trigger concentration” of 300 μg Zn/g. Small yields of hypocotyls were obtained at 1000 μg Zn/g. A 50% yield reduction occurred at tissue Zn concentrations from 36.1–1013 μg/g. The shape of Zn uptake curves suggested that hypocotyls were “indicators” of Zn uptake but leaves were “excluders”. The relative ease with which radish is grown in terms of climate and supervision together with its growth properties on contaminated soil suggest it is suitable as a monitor crop for derelict land.     

Fractional composition of humus in leached chernozems and gleyed podzolized chernozem-like soils of the northern forest-steppe zone

The composition of humus in leached chernozems differs from that in gleyed podzolized chernozem-like soils in the northern forest-steppe zone of European Russia. Leached chernozems have the fulvate-humate humus. Gleyed podzolized chernozem-like soils have the humate-fulvate humus. A more aggressive composition of humus in the latter soils is caused by their overwetting and the development of gley processes under conditions of a stagnant-percolative soil water regime.     

Barley yield and soil microbial and enzyme activities as affected by contamination of two soils with lead, zinc or copper

The effects of increasing rates of Pb, Zn and Cu on extractable heavy metal levels, barley yields, basal respiration and the activities of catalase, urease, invertase and acid phosphatase were investigated in two soils in a 2-year greenhouse experiment. In the first year, barley yields were decreased by increasing additions of Pb, Zn and Cu. In the second year, increased yields were recorded at lower rates of addition of all three metals in both the chestnut and chernozem soils. Yield depressions were most marked for added Cu and least marked for Pb but, in contrast, accumulation of heavy metals in grain, in excess of recommended limits, was most pronounced for Pb and did not occur for Cu. Increasing rates of all three metals caused a decrease in basal respiration; the degree of inhibition was generally greater in the second than in the first year. After 1 year of incubation, increasing rates of addition of metals reduced all tested enzyme activities. However, after 2 years, the pattern of response was more complex, with increases in enzyme activities being noted at lower rates of addition of all three metals. In general, invertase and urease activities were more markedly inhibited by heavy metal contamination than those of catalase and phosphatase. Ammonium acetate-extractable heavy metal concentrations in soils were less after 2 years than 1 years reaction time due to their transformation into less labile forms. Significant negative correlations between grain yield, basal respiration and enzyme activities were observed in both years.