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The washed and unwashed current (C) and previous year (C + 1) needles, branches and top soils of Pinus tabulaeformis trees were sampled at five sites Haitai industrial district (HT), Puji River (PJ), Fukang road (FK), Residential area (RA) and Baxian Mountain (BX) in Tianjin along an urban-rural gradient and analyzed for heavy metals (Cu, Mn, Zn, Pb and Cd) concentrations via ICP. C + 1 needles generally had higher Mn, Pb, Cd than C needles while the opposite was for Cu and Zn. Total Cu, Zn, Pb, Cd in soils peaked at HT and decreased at RA and BX. Heavy metals were generally higher in the unwashed needles than the washed needles at all sites. Meanwhile MDA, soluble sugar and free proline concentration in needles were increased with the increasing of heavy metal contents along the urban-rural gradient, further correlated with the heavy metal contents. [ABSTRACT FROM AUTHOR]

Spatial patterns of soil heavy metal potential ecological risk are important for the scientific pollution management of bamboo forests. A total of 160 soil samples were collected from typical moso bamboo forests in the southeastern region of China. Ecological risk index and GIS-based kriging methodologies were applied to analyze spatial variations of analyzed metals and were compared to background levels in samples collected from Zhejiang Province. The results show that the exceeded background rate of the single-factor pollution index of Pb, Cd and Cu in all soil samples is greater than 50%, with the highest overbackground rate of Pb being 99.38%. The potential ecological risk of Hg, Pb and Cd reaches a stronger risk level, while other heavy metals such as As, Cu and Cr are associated with a slight risk level. Different spatial patterns across the whole study area indicate that the potential ecological risk in the northwest and southeast areas is high, but is relatively low in the north-central area. [ABSTRACT FROM AUTHOR]

A field-based study and laboratory tests were undertaken to determine the functional diversity of microorganisms in metal- and alkali-contaminated soils in Central and North-eastern Slovakia where iron ore and magnesite have been mined and processed for a long time. To improve the understanding of the functional diversity of microorganisms, we examined the effects of environmental factors on the functional diversity of microorganisms in metal- and alkali-contaminated soils in the emission field of heaps and tailings impoundments of iron ore mines (Central Spiš) and magnesite factories (Jelšava and Lubeník). BIOLOG® Eco Plates were used to determine and assess metabolic profiles of microbial communities. The examined area of Central Spiš showed extremely high values of Hg and Cu and the values of Zn, Cd, Pb and Cr exceeding the permissible limit were determined. Soil reaction was extremely acidic to strongly acidic. The Jelšava and Lubeník area was characterized by alkaline contamination and the soil reaction was slightly acidic to strongly alkaline. The values of Cr, Mn, and Mg exceeding the permissible limit were measured there. The results indicate harmful and even toxic contamination. Our results showed that the diversity of microorganisms was different in the investigated areas and it was significantly influenced by environmental factors such as soil reaction, bulk density, porosity, and heavy metals Hg, Pb, Cr, Zn, Cu, Mn and Mg. Based on the results of the Shannon index, we can conclude that the diversity was low to moderate (2.5-3.3) and medium (3.3-4.0). Correlations between functional diversity of microorganisms and soil reaction, Hg, Cr, and Cu were determined. Our findings are decisive for understanding the microbial diversity in metal- and alkali-contaminated soils and they can be used to assess the quality and health of soil, as well as for scientific applications of remediation techniques. [ABSTRACT FROM AUTHOR]

Aims: The objectives of this study were to determine the valence state of Se and major components in Se ore powder, examine its effect on Se enrichment in crops under different cultivation patterns, and assess the safety of edible parts of crops.Methods: Se ore powder from Enshi was subjected to compositional analysis by X-ray photoelectron spectroscopy and applied to rice (wetland) and soybean (dryland) fields before planting.Results: Se was mainly present in tetravalent and zero-valent forms at a 4:6 ratio in Se ore powder. Following soil application of Se ore powder, concentrations of As, Hg, Cr, and Pb in brown rice and soybean seed were below the limit of detection, and the Cd concentration was below the European Union food regulation limit. Organic Se accounted for more than 96% of total Se in both crops, including >91% Se-methionine. Compared with dryland, the flooded environment facilitated residual Se transformation into Fe/Mn oxide-bound Se, and thus increased the potential activity of Se in the soil.Conclusions: Se ore powder can be applied for the production of Se-rich agricultural products in the short-term, and possibilities of upgrading the Se ore product should be considered in the future. [ABSTRACT FROM AUTHOR]

While metal pollution and distribution in soil are well documented for many countries, the situation is more serious in developing countries because of the rapid increase in industrialization and urbanization during last decades. Although it is well documented in developed countries, data about substantial metal pollution in Indian soil, especially in eastern Ganges alluvial plain (GAP), are limited. In this study, eight different blocks of Patna district located in eastern GAP were selected to investigate the contamination, accumulation, and sources of metals in surface soil considering different land use types. Additionally, human health risk assessment was estimated to mark the potential carcinogenic and non-carcinogenic effect of metals in soil. The concentration of all metals (except Pb) in soil was below the Indian standard limit of the potential toxic element for agricultural soil. Pb was the most abundant in soil, followed by Zn and Cu, and accounted for 52, 33 and 8% of the total metal. In terms of land use types, roadside soil detected higher concentrations of all metals, followed by park/grassland soil. Principal component analysis results indicated traffic pollution and industrial emissions are the major sources of heavy metals in soil. This was further confirmed by strong inter-correlation of heavy metals (Cd, Cr, Ni, Cu and Pb). Human health risk assessment results indicated ingestion via soil as the primary pathway of heavy metal exposure to both adults and children population. The estimated hazard index was highest for Pb, suggesting significant non-carcinogenic effect to both adults and children population. The children were more prone to the non-carcinogenic effect of Pb than adults. However, relatively low cancer risk value estimated for all metals suggested non-significant carcinogenic risk in the soil. [ABSTRACT FROM AUTHOR]

Application of wood ash to forest soils is used to counteract acidification and to reintroduce nutrients otherwise lost by harvesting, particularly in silvicultural systems with intensified biomass removal. pH governs many essential processes like nutrient availability for plant uptake, heavy metal mobility and ecosystem functioning in forest soil, but changes in soil pH on a micro scale after ash application have not been reported. The aim of this study was therefore to investigate micro vertical changes in soil pH and base cations over time after application of wood ash on forest soil. A column experiment with repacked O- and A-horizon forest soil was constructed and treatments of 0, 3 and 9 t wood ash ha −1 were applied on top of the soil in replicates of three. Soil cores were extracted from the columns monthly over one year for pH micro sensor measurements of O- and A-horizon (0–5 cm soil depth) and at four occasions (62, 152, 278 and 363 days after treatment) additional soil cores were extracted for base cation analysis. Results showed that ash application creates strong pH gradients ranging from pH 11 to 4.5 within the top 1–1.5 cm of the soil, with the highest variation within the first 50 days after application. Application of ash increases the nutrient availability. If micro scale variation is not considered, mean pH values can be a misleading indicator for the extreme conditions that can exists in the top part of the soil after ash application. [ABSTRACT FROM AUTHOR]

Among heavy metal plants (the metallophytes), facultative species can live both in soils contaminated by an excess of heavy metals and in non-affected sites. In contrast, obligate metallophytes are restricted to polluted areas. Metallophytes offer a fascinating biology, due to the fact that species have developed different strategies to cope with the adverse conditions of heavy metal soils. The literature distinguishes between hyperaccumulating, accumulating, tolerant and excluding metallophytes, but the borderline between these categories is blurred. Due to the fact that heavy metal soils are dry, nutrient limited and are not uniform but have a patchy distribution in many instances, drought-tolerant or low nutrient demanding species are often regarded as metallophytes in the literature. In only a few cases, the concentrations of heavy metals in soils are so toxic that only a few specifically adapted plants, the genuine metallophytes, can cope with these adverse soil conditions. Current molecular biological studies focus on the genetically amenable and hyperaccumulating Arabidopsis halleri and Noccaea ( Thlaspi ) caerulescens of the Brassicaceae. Armeria maritima ssp. halleri utilizes glands for the excretion of heavy metals and is, therefore, a heavy metal excluder. The two endemic zinc violets of Western Europe, Viola lutea ssp. calaminaria of the Aachen-Liège area and Viola lutea ssp. westfalica of the Pb-Cu-ditch of Blankenrode, Eastern Westphalia, as well as Viola tricolor ecotypes of Eastern Europe, keep their cells free of excess heavy metals by arbuscular mycorrhizal fungi which bind heavy metals. The Caryophyllaceae, Silene vulgaris f. humilis and Minuartia verna , apparently discard leaves when overloaded with heavy metals. All Central European metallophytes have close relatives that grow in areas outside of heavy metal soils, mainly in the Alps, and have, therefore, been considered as relicts of the glacial epoch in the past. However, the current literature favours the idea that hyperaccumulation of heavy metals serves plants as deterrent against attack by feeding animals (termed elemental defense hypothesis). The capability to hyperaccumulate heavy metals in A. halleri and N. caerulescens is achieved by duplications and alterations of the cis -regulatory properties of genes coding for heavy metal transporting/excreting proteins. Several metallophytes have developed ecotypes with a varying content of such heavy metal transporters as an adaption to the specific toxicity of a heavy metal site. [ABSTRACT FROM AUTHOR]

Seabirds are an important factor affecting the chemical properties of the arctic soil environment. The objective of this work was to study the differences in content and distribution of heavy metals in organic soils resulting from the differential influence of seabirds. Studies were conducted in two stations in the southwest part of Spitsbergen-the first without the influence of seabirds and the second directly affected by an avian colony. Basic properties of soils as well as total content of Ca, Na, Mg, K, Fe, Al, Cu, Zn, Ni, Mn, Pb, Cd, Co, and Cr were determined. Reference was made to the previously published contents of different forms of phosphorus (P) for these locations. The studies showed that Zn, Mn, Cu, and Cd contents were higher in the soils that had been in the vicinity of the seabird colony. High statistically positive correlations of Cd, Cu, and Zn were noted with particular P forms. In the case of Pb, Cr, Co, and Ni content, the seabird influence was not dominant; probably other factors were more relevant (the processes of weathering, denudation, leaching, and atmospheric pollutants transported in the form of dust or gases). Clear segregation was observed of individual positions conditioned by selected soil features and by heavy metals content. [ABSTRACT FROM AUTHOR]

Forests play an important role in global mercury (Hg) cycling. To explain the high Hg accumulation in subtropical forest ecosystems, we studied temporal dynamics of Hg, carbon (C), nitrogen (N), and sulfur (S) in forest soil profiles, as well as litterfall flux and precipitation, in an old-growth moist evergreen broadleaf (EB) forest and a mossy coppice (MC) forest from South China over seven years. The mean soil Hg concentration was 257 ± 14 ng g −1 in the O-horizon and 248 ± 15 ng g −1 in the A-horizon for the EB forest, and 94 ± 27 ng g −1 in the O-horizon and 70 ± 11 ng g −1 in the A-horizon for the MC forest. Annual variations in Hg concentration were suggested to be associated with variations in precipitation and litterfall biomass. Significant vertical Hg transport was only observed in the MC forest, which was attributed to its lower organic matter content. Correlation and stoichiometry analyses further suggested that the dynamics in Hg concentration in the forest floor was also closely linked to the variation in S concentration. Additionally, the difference in the soil Hg pool between these two forests was attributed to different litterfall biomass fluxes. [ABSTRACT FROM AUTHOR]

The present study attempts to analyze the biosorption trend of biosorbent Sargassum sp (macroalgae) biomass for removal of toxic heavy metal ion Cd (II) from solution as a function of initial metal ion concentration, pH, temperature, sorbent dosage. The sorption data fitted with various isotherm models and Freundlich model was the best one with correlation coefficient of 0.999. Kinetic study results revealed that the sorption data on Cd (II) with correlation coefficient of 0.999 can best be represented by pseudo second-order. The biosorption capacity (qe) of Cd (II) is 9.75 mg/g on Sargassum sp biomass. Thermodynamic studies showed that the process is exothermic (ΔH° negative).Free energy change (ΔG°) with negative sign reflected the feasibility and spontaneous nature of the process. The SEM studies showed Cd (II) biosorption on selective grains of the biosorbent. The FTIR spectra indicated bands corresponding to -OH, COO-, -CH, C=C, C=S, and -C-C- groups were involved in the biosorption process. [ABSTRACT FROM AUTHOR]

Assessing current Hg pools in forest soils of the northeastern U.S. is important for monitoring changes in Hg cycling. The forest floor, upper and lower mineral horizons were sampled at 17 long-term upland forest sites across the northeastern U.S. in 2011. Forest floor Hg concentration was similar across the study region (274 ± 13 μg kg−1) while Hg amount at northern sites (39 ± 6 g ha−1) was significantly greater than at western sites (11 ± 4 g ha−1). Forest floor Hg was correlated with soil organic matter, soil pH, latitude and mean annual precipitation and these variables explained approximately 70% of the variability when multiple regressed. Mercury concentration and amount in the lower mineral soil was correlated with Fe, soil organic matter and latitude, corresponding with Bs horizons of Spodosols (Podzols). Our analysis shows the importance of regional and soil properties on Hg accumulation in forest soils. [Copyright &y& Elsevier]

Significant concern has emerged over the past decades regarding decreases in available base cations (that is, calcium, magnesium, potassium, and sodium) in forest soils and surface waters. Base cations (BCs) are important for buffering against changes in soil and water acidity, and their concentrations can be indicative of environmental management problems such as those linked to acid deposition and land use. Climate variability is also a potentially large factor influencing the dynamics of BCs in soils and surface waters, but our understanding of these interactions at broad scales remains elusive. We used a hierarchical Bayesian model to evaluate the long-term (1990-2010) patterns and drivers of BC concentrations for 60 stream and river monitoring stations across Sweden. Results indicated that the long-term trends in concentration, and the associated environmental drivers, differed among individual BCs and geographical regions. For example, we found that concentrations of Ca, Mg, K, and Na have decreased in southern Sweden since 1990 and that this is strongly related to concurrent declines in sulfate (SO) over the same period of record. In contrast, concentrations of Ca, Mg, K, and Na in northern Sweden did not exhibit significant directional trends, despite declines in SO, nitrate (NO), and chloride (Cl) over the same period. Instead, BC dynamics in the north are characterized by inter-annual variability that is most closely linked to climate variables. Results suggest that the interaction between climatic variability and historical acid deposition determines the regional pattern and long-term trends of BC concentrations across streams and rivers of Sweden. Understanding the strength of the interaction between climate features and historic deposition will greatly improve our ability to predict long-term trends of Ca, Mg, K, and Na and their inter-annual dynamics in the future. [ABSTRACT FROM AUTHOR]

Purpose: The heavy metal lead (Pb) is toxic to living organisms. Forest soils are important sinks for heavy metals generated by human activities. The forest at Dinghushan of southern China has experienced long-term exposure to atmospheric pollutants from the Pearl River Delta (PRD). The objectives of this research were (a) to determine the vertical and temporal distribution of Pb in the forest soil at Dinghushan, (b) to determine whether dilute acid extraction could be used to identify anthropogenic sources of Pb in forest soil, and (c) to determine the main anthropogenic contributors to soil Pb. Materials and methods: Lead concentrations and isotopes were measured in two sets of forest soil samples. One set consisted of archived samples from 0 to 20 cm depth collected annually from 1997 to 2010. The other set was collected throughout three profiles sampled at 5-cm intervals to the bedrock (85 cm depth) in 2011. The soil samples were air-dried, ground, and passed through a 100-mesh polyethylene sieve. Lead in the samples was digested with concentrated acid (HNO + HClO, 4:1 v/ v) or extracted with dilute acid (1 M HCl with a soil/solution ratio of 1:10) and was measured with an inductively coupled plasma mass spectrometer. Results and discussion: Concentrations of Pb obtained both by total digestion and dilute acid extraction decreased with soil depth in the profile samples and increased over time in the archived ones. Soils at 0-20 cm depth had Pb concentrations of more than twice of the local soil background value. In all soil samples, the Pb ratios was lower and the Pb, Pb, and Pb ratios were higher with the dilute acid extraction than with the strong-acid digestion, indicating that dilute acid extraction could be used to distinguish between anthropogenic and geogenic Pb. Comparison of the Pb isotope ratios in the samples with those in the main pollutants from the PRD indicated that coal combustion and industrial emission were the main contributors to the forest soil Pb at Dinghushan. Conclusions: The forest soil (0-20 cm depth) at Dinghushan was contaminated by Pb. Dilute acid extraction could be used to identify anthropogenic Pb sources. From 1997 to 2010, the main contributors of anthropogenic Pb to the forest soil at Dinghushan were coal combustion and industrial emission. Measures that control Pb emission from coal combustion and industrial activity, changes in coal consumption, and re-adjustments of industry development in the PRD should reduce Pb contamination of forest soil. [ABSTRACT FROM AUTHOR]

Abstract: With the conception that whole tree harvesting leads to an impoverishment of forest soils wood ash application is recommended, with the foremost benefits being increased pH in soil and subsequent surface waters, and recycling of nutrients from the wood ash. In this investigation a small boreal catchment in central Sweden was studied for 2years before and 2years after treatment with the maximum recommended dose, 3 tonnes/ha, of crushed, self-hardened wood ash. The sampling area was situated in a slope towards a stream, to include the effect on both recharge- and discharge areas with different soil constitutions. The soil solution chemistry, exchangeable pool of cations and potential heavy metal accumulation in berries were studied. Temporary increases in soil solution concentration were found for K in the recharge area and Ca and SO4 in the discharge area when comparing ashed and control areas. No change in exchangeable cations was observed during the study period, and no increase of heavy metals in bilberries did occur. These small changes in the constitution of the soil solution do not suggest wood ash application as a method to improve soil quality in an initial phase. [Copyright &y& Elsevier]

The content of microelements (Mn, Zn, Cu, Co, Ni, Cr, Pb, and Cd) and Fe is determined in the soils and plants of the Lake Kotokel' basin. Their content in the soils is proved not to exceed the regional background and the existing MPC and APC. The content of Cd is revealed to exceed its clarke value for the world soils, which is related to the natural origin of this element. The concentrations of Mn, Co, and Pb are close to their clarke values, and those of Zn, Cu, Ni, and Cr are lower than their clarkes. The studied soils are specified by the maximal amount of the mobile forms of microelements. The profile distribution of the microelements differs depending on the genetic soil type. For Mn, Zn, and Cu, a significant biogenic accumulation is pronounced in the organic soil horizons. The content of microelements in the aboveground phytomass exceeds the maximal permissible levels for Mn, Co, Cr, and Fe. The intensity of the microelements absorption by the plants varies widely, being specified by the high coefficient of the biological adsorption (except for Fe). Mn, Zn, and Cu are accumulated in the plant phytomass the most intensely. [ABSTRACT FROM AUTHOR]

Little is known about the variability of response to heavy metal stress within tree species, although it could be a key for a better understanding of tolerance mechanisms and for breeding. The aim of the present study was to characterize the natural variation of response to cadmium (Cd) in Populus nigra L. in order to understand the mechanisms of Cd tolerance. For that, two P. nigra genotypes, originating from contrasting environments in northern (genotype 58-861) and southern (genotype Poli) Italy, were exposed to Cd stress in hydroponics for 3 weeks. The effect of stress was estimated by measuring biomass production, photosynthetic performance and accumulation and translocation of Cd at the end of the experiment. To better understand the mechanisms of Cd tolerance, the expression of some candidate genes involved in the ascorbate–glutathione cycle (ascorbate peroxidase, glutathione reductase, glutathione S-transferase) and in metal sequestration (metallothioneins) was analyzed in leaves. Biomass production and photosynthesis were affected by the treatment in both clones but the southern clone was markedly more tolerant to Cd stress than the other. Nevertheless, the Cd content in leaves was not significantly different between the two clones and was quite low compared to other species. The content of thiols and phytochelatins (PCs), associated with the transcription profile of the glutathione S-transferase gene, indicated relevant differences in the use of the PCs pathway under Cd stress, which could explain the different tolerance to Cd. The northern clone accumulated thiols but down-regulated the GST gene, whereas the southern clone accumulated PCs and up-regulated the GST gene, which can be useful to complex and detoxify Cd. These results suggest that the glutathione pathway is involved in the differential Cd tolerance of the two genotypes. The natural germplasm of P. nigra represents a valuable resource for understanding tolerance to Cd and for selection of plant material for phytoremediation. [ABSTRACT FROM PUBLISHER]

Abstract: This article summarizes trends in total Hg concentrations (THg) in fungal fruiting bodies (basidiomata) and their underlying soil substrates in the absence and presence of surrounding moss layers. Three forest locations across south-western New Brunswick spanning from a central mainland location to Grand Manan Island in the Bay of Fundy were chosen for the study. Geographic location had an effect on THg in the soil layers and in the basidiomata (THg on island>THg along the mainland coast>THg mainland) but this effect was weak and probably obscured by the large THg variations within the basidiomata and their soil and moss substrates at each location. Within the soil, THg increased with increasing total organic S (TS) and C (TC) concentrations, and depended on type of moss cover if present. Within the mosses, THg varied by species, by moss-internal TS, and by THg and TS within the underlying soil. Basidiomatal THg also varied strongly by species, and was further affected by: (i) developmental stage, from emergence to senescence, (ii) cap versus stalk, (iii) basidiomatal TS, and (iv) soil THg, TS and TC. These variations and their interdependencies were explored and quantified by way of multiple regression analyses. Basidiomatal bioconcentration of soil THg (F layer) varied strongly by species as well. Basidiomatal Hg extraction from the soil was estimated to be small in terms of reducing the accumulated Hg loads within the soil, but represents a re-entry point of Hg into the local food chain. [Copyright &y& Elsevier]

Purpose: Gongga Mountain, the highest mountain in Sichuan Province and the eastern edge of the Tibetan Plateau, is usually regarded as the 'clean' area and free from heavy metal contamination because it is far away from intensive human activities. The purpose of this study is to discover the enrichment characteristics of cadmium (Cd) in soil of Gongga Mt. and probe into its provenance. Materials and methods: Thirty-three soil profiles were hand-dug and totally 114 soil samples were collected from different altitude and vegetation zone. Meanwhile seven samples of glacial debris at the foreland of Hailuogou glacier were collected to be used to determine the background of Cd. Cd and other element contents in soil samples were measured using ICP-AES and ICP-MS after acid digested. Enrichment factor (EF) together with the Cd content in precipitation samples were used to determine the source of Cd. Results and discussion: Four soil units were divided according to the primary aspect in the field. In the surface A0 soil horizon, the Cd content varied between 0.2 and 7.86 mg/kg while in A soil horizon, it was between 0.11 and 5.61 mg/kg. The background value of Cd in Gongga Mt. was estimated at 0.22 mg/kg according to the Cd content in the deeper layer of soil profiles and glacial debris at the foreland of Hailuogou glacier. The EF of Cd was hence calculated to determine the state of Cd enrichment and its provenance. The Cd content in precipitation, relationship between Cd content and soil grain-size component, relationship between Cd content and soil organic carbon content, together with Cd EF indicated that the atmospheric deposition is the major source of soil Cd. Conclusions: As EF revealed, the Cd contamination in the surface soil of Gongga Mt. area has reached a serious level, especially in the coniferous zone. The atmospheric deposition is the major source of soil Cd. [ABSTRACT FROM AUTHOR]

Carabid beetles (Coleoptera, Carabidae) are one of the most studied soil groups in relation to heavy metal (HM) accumulation and use for bioindication of environmental pollution. Accumulation of Zn and Cu in carabid beetles was species-, sex- and trophic group-specific. No differences were found in HM contents between omnivorous and carnivorous species. The use of carabid beetles as indicators of HM accumulation appears to be rather limited. [ABSTRACT FROM AUTHOR]

Floristic investigations concerning vascular plants, supplemented by a determination of the basic soil parameters and concentration of four heavy metals (Cu, Zn, Mn, Fe), were carried out in 12 railway areas located in north-eastern Poland (eight located on tracks withdrawn from use, four located on operating tracks). The vegetation types of the areas in the immediate vicinity of the selected sites differed (forest, grassland or meadow, ruderal). The soil samples exhibited considerable uniformity with respect to their pH values, and, although the nutrient levels varied, the concentration of the latter did not seem to be a factor limiting plant growth. The concentration of heavy metals did not hinder plant growth. Although the chemical features of the soil were within limits that did not make plant growth difficult, the process of plant regeneration proceeded differently, depending on the accessibility of diaspores from the surrounding areas. The decreasing rate of therophytes, especially aliens, manifested a stage of succession on abandoned tracks. In the case of ground flora, gradual 'preparation' of the habitat (shadow factor on the track) was very important. The degree of advancement of forest regeneration on abandoned tracks was more strongly evidenced by the constant return of ground flora species, and not by trees as was commonly thought. [ABSTRACT FROM AUTHOR]

The complexation of heavy metals, present in their dissolved state at relevant trace levels, with new humic acids (HAs) isolated from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils has been studied by differential pulse anodic stripping voltammetry (DPASV) at a hanging mercury drop electrode and conductimetry methods. After extraction and purification, humic acids were characterized by elemental analyses, atomic absorption spectroscopy, FT-IR, and solution state C-NMR. Taking Zn(II) and Cd(II) as examples, the aim of this study was to gain direct information on the general level of importance of humic acids for the speciation of certain heavy metals in soil to determine the complexing capacities of AHs and stability constant of the complexes formed with these metal ions and to compare the complexation capacity of forest and Sahara soils with the commercial humic acid and other published AHs. The results determined by conductimetry method are interpreted using an excess function (∆ k) which related the conductivity of the mixture and of the separated components. A positive value of this function is obtained. It indicates the complexation of humic acids with metallic ions. The DPASV method was used for determining metal ion complexing capacities and stability constants of metal ion complexes of HAs in solution at pH 7. In both types of soils, the commercial humic acid (CHA) is less efficient in complexing Zn(II) and Cd(II) than THA and YHA and the complexing capacity (CC) decreases in the order: THA > YHA > CHA. In general, the results of complexing capacity for all humic acids and stability constants of Zn(II) and Cd(II) complexes found by DPASV method showed good correlation with those of conductimetry method. CC of THA and YHA calculated by DPASV were higher than those of CHA and the other natural HAs published in the literature at pH 7 basing on these results. [ABSTRACT FROM AUTHOR]

Stress originating from toxicants such as heavy metals can induce compensatory changes in the energy metabolism of organisms due to increased energy expenses associated with detoxification and excretion processes. These energy expenses may be reflected in the available energy reserves such as glycogen. In a field study the earthworm, Dendrobaena octaedra, was collected from polluted areas, and from unpolluted reference areas. If present in the environment, cadmium, lead and copper accumulated to high concentrations in D. octaedra. In contrast, other toxic metals such as aluminium, nickel and zinc appeared to be regulated and kept at low internal concentrations compared to soil concentrations. Lead, cadmium and copper accumulation did not correlate with glycogen reserves of individual worms. In contrast, aluminium, nickel and zinc were negatively correlated with glycogen reserves. These results suggest that coping with different metals in earthworms is associated with differential energy demands depending on the associated detoxification strategy. [Copyright &y& Elsevier]

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Purpose: Analyzing organic pollutants in forest soil is challenging because they are strongly physical and chemical bound to soil organic matter (SOM). Within the framework of a forest soil inventory, an analytical protocol for the determination of polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), and organochlorine pesticides (OCP) should be established and validated using one and the same extraction and cleanup procedure. The protocol should be applicable for reliable analysis of a high number of samples in a short timeframe. Materials and methods: Two different soil samples representative for the humic layer from a typical mixed and coniferous forest soil had been used for the analysis. Three solvents of different polarity, namely cyclohexane (CH), ethylacetate (EA)/CH (1/1, v/ v), and acetone (AC)/CH (2/1, v/ v), and the six standard extraction techniques (pressurized liquid extraction (PLE), soxhlet extraction, fluidized bed extraction, sonication, shaking, and one-step extraction recommended for analyzing agricultural soil in Germany (VDLUFA 2008)) were compared concerning their extraction efficiency. For additional matrix separation, two different cleanup procedures (gel permeation chromatography (GPC) and solid-phase extraction (SPE) with different sorbents) were tested. Quantification was carried out using gas chromatography combined with mass spectrometry (GC-MS) and two different injection systems (split/splitless injection and programmable temperature vaporizer (PTV) injection). Labeled internal standards, added prior to extraction, were used for method evaluation. Results and discussion: For the simultaneous extraction of PAH, PCB, and OCP from organic forest soil PLE with acetone/cyclohexane (2/1, v/ v) provided the highest extraction efficiency. A two-step cleanup procedure consisting of GPC followed by SPE with silica gel was entirely sufficient for the separation of humic substances without discrimination of analytes. Recovery rates for the different extraction and cleanup steps ranged between 89% and 106%. For quantification, a GC-MS method was developed using two different injection systems and two capillary columns of different selectivity. Conclusions: By comparing six standard extraction techniques for PAH, PCB, and OCP from forest soil, we obtained the highest extraction efficiency when using PLE with AC/CH (2/1). For sample injection, we achieved best results using an optimized PTV injection system as it highly reduced the breakdown of thermolabile pesticides. Using this combination of technical equipment, it is possible to determine a concentration of the analytes in the trace level range of 1-2 μg kg in humic soil. [ABSTRACT FROM AUTHOR]

Abstract: Vertical distribution and activity contents of 210Pb and 210Po were investigated in forest soils of Scots pine-dominated (Pinus sylvestris L.) stands from seven different locations in Finland. The mean total inventory in the soil profile, up to 20cm, of 210Pb was 4.0kBqm−2 (range3.1–5.0kBqm−2) and 210Po 5.5kBqm−2 (range 4.0–7.4kBqm−2), the organic soil layer containing 45% of the total inventory of both nuclides. In both the organic and the mineral layers the 210Po/210Pb ratio was close to unity indicating a radioactive equilibrium between them. In the litter layer there was, however, a clear excess of 210Po suggesting that polonium is recycled via root uptake from the root zone to the ground surface. The activity concentration (Bqkg−1) of 210Pb clearly correlated with organic matter and the Fe, Al and Mn concentrations in soil indicating that radioactive lead is associated both with humic substances and the oxides of iron, aluminium and manganese. Radioactive lead was also seen to follow the behavior of stable lead. No systematic correlation between polonium and soil properties was seen. [Copyright &y& Elsevier]

Anthropogenic trace element emissions have declined. However, top soils all over the world remain enriched in trace elements. We investigated Pb and Cd migration in forest soils of a remote monitoring site in the Austrian limestone Alps between 1992 and 2004. Large spatial variability masked temporal changes in the mineral soil of Lithic Leptosols (Skeltic), whereas a significant reduction of Pb concentrations in their forest floors occurred. Reductions of concentrations in the less heterogeneous Cambisols (Chromic) were significant. In contrast, virtually no migration of Pb and Cd were found in Stagnosols due to their impeded drainage. Very low element concentrations (<1 μg l−1) in field-collected soil solutions using tension lysimeters (0.2 μm nylon filters) imply that migration largely occurred by preferential flow as particulate-bound species during intensive rainfall events. Our results indicate that the extent of Pb and Cd migration in soils is largely influenced by soil type. [Copyright &y& Elsevier]

Abstract: Vast amounts of knowledge about the proton- and metal-binding properties of dissolved organic matter (DOM) in natural waters have been obtained in studies on isolated humic and fulvic (hydrophobic) acids. Although macromolecular hydrophilic acids normally make up about one-third of DOM, their proton- and metal-binding properties are poorly known. Here, we investigated the acid–base and Cu-binding properties of the hydrophobic (fulvic) acid fraction and two hydrophilic fractions isolated from a soil solution. Proton titrations revealed a higher total charge for the hydrophilic acid fractions than for the hydrophobic acid fraction. The most hydrophilic fraction appeared to be dominated by weak acid sites, as evidenced by increased slope of the curve of surface charge versus pH at pH values above 6. The titration curves were poorly predicted by both Stockholm Humic Model (SHM) and NICA-Donnan model calculations using generic parameter values, but could be modelled accurately after optimisation of the proton-binding parameters (pH⩽9). Cu-binding isotherms for the three fractions were determined at pH values of 4, 6 and 9. With the optimised proton-binding parameters, the SHM model predictions for Cu binding improved, whereas the NICA-Donnan predictions deteriorated. After optimisation of Cu-binding parameters, both models described the experimental data satisfactorily. Iron(III) and aluminium competed strongly with Cu for binding sites at both pH 4 and pH 6. The SHM model predicted this competition reasonably well, but the NICA-Donnan model underestimated the effects significantly at pH 6. Overall, the Cu-binding behaviour of the two hydrophilic acid fractions was very similar to that of the hydrophobic acid fraction, despite the differences observed in proton-binding characteristics. These results show that for modelling purposes, it is essential to include the hydrophilic acid fraction in the pool of ‘active’ humic substances. [Copyright &y& Elsevier]

New humic acid isolated from forest soil of Yakouren (YHA), Algeria, and purified commercial humic acid (PCHA) were analyzed and characterized. Elemental analyses, electronic microscopy, UV-Vis absorbance E465/E665 ratio and molecular spectroscopy investigation using CP-MAS 13C-NMR of YHA indicated the presence of a high content of aliphatic and carboxylic acid groups. The higher O/C, H/C and N/C ratios of YHA can be assigned to the low aromatization degree. A study of interaction between Ni(II), Zn(II), Cd(II) and humic acids (HAs) at different metal-ligand ratios has been made by conductimetric and fluorescence techniques. The results obtained by the conductimetry method are interpreted using an excess function (Δk), which related the conductivity of the mixture and of the separated components. A positive value of this function is obtained. It indicates the complexation of HAs with metallic ions. The association degree of the heavy metals (M) with both HAs was in the following order: Ni > Zn > Cd and the binding capacity of PCHA is smaller than that of YHA. A fluorescence titration method and a single site model were used for determining metal ion complexing capacities (CCM) and stability constants (log KM) of YHA and PCHA complexes. Titration of HAs with metal ions at pH 7 and ionic strength 0.1 mol/L resulted in a marked decrease of fluorescence intensities of untreated HAs. The quenching constants (KSV) between HAs and M are obtained in terms of Stern-Volmer analysis. KSV show that the YHA binds the higher amount metals than PCHA. CCM of YHA calculated by MATLAB program were higher than those of PCHA and other natural HAs found in the literature at pH 7. Based on these results, YHA may play the role of a biocaptor of polluting metals. [ABSTRACT FROM AUTHOR]

The work focuses on application of linear regression method for assessment of soil physicochemical parameters influence on 137Cs accumulation. Besides organic matter content and pH, the parameters related to sorption properties of mineral parts and mobile ions concentration were considered. Before linear regression model is applied the data were transformed using Box–Cox formula. Selection of explanatory variables for regression was based on Akaike Information Criterion (AIC). Analysis of residuals distribution showed that linear regression can be applied for assessment of Cs+ accumulation in soil horizons. The important conclusion is that Cs+ cation migration in soil is usually influenced by more than a single horizon parameter. Common influence of two or more parameters on 137Cs activity in soil horizon was observed. Our results suppose that migration of Cs in soil is affected mainly by horizon’s acidity, presence of minerals and ion exchangeable substances. Some processes are probably affected by Cs+ individual properties, but other ones are not so selective. [ABSTRACT FROM AUTHOR]

Soil samples from agricultural and adjacent forest soils in Northwest Ohio were collected and analyzed for As, Cr, Cu, Ni, Pb, and Zn. pH, Eh, electrical conductivity, and moisture content were also measured. Selected samples were also evaluated for grain size and X-rayed to identify clay minerals. In this region, soils contain a large proportion of fines (∼32% clay and ∼37% silt) with illite, dickite, and chlorite as the main clay minerals. Surface soils in the arable land are slightly acidic (pH ∼5.6) while forest soils are near-neutral to slightly basic. All soils become more basic with depth. Soil Eh and electrical conductivity range from 300 to 450 mV and 100 to 375 μS, respectively. In the soil profiles, between 0 and 50 cm depth, As increases from 4.6 to 11 mg/kg, Cr increases from19 to 23 mg/kg and Ni increases 21 to 29 mg/kg. In contrast, Cu decreases from 23 to 17 mg/kg and Pb decreases from17 to 10 mg/kg. Surface enrichment of Cu and Pb can be the result of aerosol deposition, while the downward increase in As, Cr and Ni is related to pedogenic variation. The average concentration of Zn in the samples is 64 mg/kg and does not change with land-use or depth. With the exception of As, the concentration of metals in the agricultural soil is not significantly different from the concentration in forest soil. The concentration of As in the near-surface arable soil (5.6 mg/kg) is significantly different from the concentration of As in the near-surface forest soil (4.3 mg/kg). In both cases, deeper soils have similar As contents. The relative enrichment of As in the surface arable soil could indicate input from herbicides or pesticides. The upward increase in electrical conductivity is interpreted to show that the exchangeable fraction of each metal is higher in the surface soils. However, the near neutral pH and organic, clay-rich soils may limit the mobility. The concentration of these heavy metals and As in the soils are much lower than the limits set by the United States Environmental Protection Agency. [ABSTRACT FROM AUTHOR]

Abstract: Forest floor in acid forest soils is a major source of dissolved organic carbon (DOC), nutrients and metals. We studied the release of DOC, nutrients and metals from two forest floors under beech stands (a moder from a Cambisol and a mor from a Podzol). We analyzed the composition of the solid phase, and we monitored the chemical properties of forest floor leachates through incubation-leaching experiments at 4 and 20 °C. Our data show that the release of DOC, nutrients and metals strongly differed between both forest floors. Whatever the temperature, the release of DOC, DIN, divalent cations and heavy metals, as compared to initial stocks of corresponding elements, were the largest in moder leachates. Instead, the release of K+, Na+, Si, Al and Fe were the largest in mor leachates at 20 °C, and were generally similar for both forest floors at 4 °C. The ionic signature of the leachates was strongly affected by DOC release and nitrogen mineralization, which was mostly directed towards the production of ammonium in mor, and of nitrate in moder. In moder leachates at 20 °C, Ca2+ was the dominant cation, and nitrate the major anion. Instead, in mor leachates, NH4 + was the major cation, and organic anions dominated the anionic charge. Despite the dominance of organic anions in mor leachates, the concentrations of cations and Si were strongly correlated to the concentrations of inorganic anions in leachates from both forest floors. The concentration of Al, Fe, Cu and Pb were strongly correlated to the concentration of organic anions, whereas Zn concentration was poorly correlated with either organic or inorganic anions. [Copyright &y& Elsevier]

Abstract: The aim of the study was to establish whether the repeated application of sewage sludge to an acid forest soil (Dystric Cambisol) would lead to short-term groundwater contamination. Sludge was applied at four loading rates (0, 2.4, 17 and 60Mgha−1) in two consecutive years and leachates were analysed. Heavy metal inputs to soils at the lowest dose were below EC regulations but, at higher doses, limits for Zn, Cd, Cr and Ni were exceeded. Repeated application of sludge at 60Mgha−1 resulted in significantly (P <0.05) higher concentrations of Zn, Cd, Cr and Ni in the leachates than with other treatments. The drinking water standards for Cd and Ni were surpassed in all treatments. Control plots were contaminated by groundwater flow despite the existence of buffer zones between plots. This complicated interpretation of the results, highlighting the importance of careful design of this type of experiment. [Copyright &y& Elsevier]

The potential environmental risk posed by metals in forest soils is typically evaluated by modeling metal mobility using soil-solution partitioning coefficients (Kd), although such information is generally restricted to a few well-studied metals. Soil-solution partitioning coefficients were determined for 17 mineral elements (Al, As, Be, Ba, Ca, Cr, Cu, Fe, Ga, K, Li, Mg, Rb, Sr, Tl, U and V) in A-horizon (0–5 cm) soil at 46 forested sites that border the Precambrian Shield in central Ontario, where soil pHaq varied from 3.9 to 8.1. Sites were dominated by mature sugar maple ( Acer saccharum Marsh.), white birch ( Betula papyrifera Marsh.), balsam fir ( Abies balsamea (L.) Mill.) or white pine ( Pinus strobus L.). Log Kd values for all elements could be predicted by empirical linear regression with soil pH ( r 2 = 0.17–0.77) independent of forest type, although this relationship was greatly affected by positive relationships between acid-extractable metal concentration and pHaq for 13 of the 17 elements. Elements that exhibited strong or moderate ( r 2> 0.29; p < 0.001) relationships with soil pHaq in soil water extracts include Al, Ba, Fe, Ga, K, Li, Rb, Tl, V (negative) and Ca (positive). Elemental partitioning in mineral soil was independent of forest type; tree species differed in their response to chemical differences in mineral soil. For example, Rb, Ba, and Sr concentrations in foliage of sugar maple and white birch significantly increased with increasing soil acidity, whereas Rb, Ba, and Sr concentrations in balsam fir and white pine foliage exhibited no response to soil pHaq. While Kd values can provide useful information on the potential mobility and bioavailability of mineral elements in forest soils, care must be used when interpreting the relative contribution of solid and aqueous phases to this relationship and the differing responses of vegetation in elemental cycling in forests must also be considered. [ABSTRACT FROM AUTHOR]

Minerals with large specific surface areas promote the stabilization of soil organic matter (SOM). We analysed three acidic soils (dystric, skeletic Leptic Cambisol; dystric, laxic Leptic Cambisol; skeletic Leptic Entic Podzol) under Norway spruce ( Picea abies) forest with different mineral compositions to determine the effects of soil type on carbon (C) stabilization in soil. The relationship between the amount and chemical composition of soil organic matter (SOM), clay content, oxalate-extractable Fe and Al (Feo; Alo), and dithionite-extractable Fe (Fed) before and after treatment with 10% hydrofluoric acid (HF) in topsoil and subsoil horizons was analysed. Radiocarbon age, 13C CPMAS NMR spectra, lignin phenol content and neutral sugar content in the soils before and after HF-treatment were determined and compared for bulk soil samples and particle size separates. Changes in the chemical composition of SOM after HF-treatment were small for the A-horizons. In contrast, for B-horizons, HF-soluble (mineral-associated) and HF-resistant (non-mineral-associated) SOM showed systematic differences in functional C groups. The non-mineral associated SOM in the B-horizons was significantly depleted in microbially-derived sugars, and the contribution of O/N-alkyl C to total organic C was less after HF-treatment. The radiocarbon age of the mineral-associated SOM was younger than that of the HF-resistant SOM in subsoil horizons with small amounts of oxalate-extractable Al and Fe. However, in horizons with large amounts of oxalate-extractable Al and Fe the HF-soluble SOM was considerably older than the HF-resistant SOM. In acid subsoils a specific fraction of the organic C pool (O/N-alkyl C; microbially-derived sugars) is preferentially stabilized by association with Fe and Al minerals. Stabilization of SOM with the mineral matrix in soils with large amounts of oxalate-extractable Alo and Feo results in a particularly stable and relatively old C pool, which is potentially stable for thousands of years. [ABSTRACT FROM AUTHOR]

Among many single-step extraction procedures proposed, 0.05 M EDTA (ethylenediaminetetraacetic acid) extraction is widely used. Although it has been often criticised, this protocol remains an effective and simple approach for a fast determination of the potential availability of several metals (e.g., Pb, Cd, Cu, Zn, etc.). However, other metallic elements present in soils at high concentrations such as Ca and Fe can possibly influence the extraction of the target metal due to competition for the EDTA ligand. The aim of this study was to evaluate the role of these metals during the 0.05 M EDTA extraction procedure. Furthermore, sequential extraction and Pb isotope analyses (206/207Pb) were used in order to obtain more detailed information. The results of this study showed that especially the concentration and crystallinity of Fe play a very important role during the extraction of the target metals from low to moderately contaminated soils and this fact should be taken into account during result interpretation. [ABSTRACT FROM AUTHOR]

The city of Torino (45°N, 7°E NW Italy) has a long history of heavy industry. Additional sources of potential pollutants originate from transport such as car emissions. We selected an area potentially at high risk of contamination: it is sandwiched between roads, the circular Turin highway and the motorway, which connects to France, and a landfill where special and hazardous solid wastes from industry are disposed of. Our main aim was: i) to discriminate between these sources of heavy metals (HM); and ii) to assess a simplified HM transfer scenario. We started with air diffusion models (inputs were meteo and chemistry of the particulate); then we described topsoils (12 samples km- 2) and we sampled, reallocated undisturbed, and cultivated an Ap soil horizon, being the soil ceteris paribus. The topsoils description discriminated Factor I, related to the vehicular load and soil parent material (mainly Cd, Co, Cr, Ni, V, and Zn), and Factor II, HM univocally dispersible from the landfill (Sb and As). The ecosystem response is resilience: soil tends to buffer loadings of most HM. In the case of mercury, lead, and arsenic our findings indicate that their transfer to the food chain may be massive. [ABSTRACT FROM AUTHOR]

The physicochemical properties and concentrations of heavy metals were determined in surface water, intertidal mudflats (epipellic) and benthic sediments obtained from the mangrove swamp ecosystem of the Qua Iboe Estuary, Nigeria. The monthly concentrations of the nutritive salts revealed that the sediments are halomorphic. Heavy metal concentrations in benthic sediments and surface water were generally lower than the values recorded for the intertidal mudflats. The mean concentrations of heavy metals obtained from estuarine surface water and intertidal and subtidal sediments were highly variable and seasonally dependent. The levels of heavy metals in the intertidal sediments were comparatively higher in the wet than the dry season. The range of concentration over the months increased by 1.3% (Cr), 1.6% (Pb), 6.0% (V), 7.5% (Ni), 10.5% (Fe), 12.0% (Zn), and 15.0% (Cu). Cr, Pb, Zn, and V concentrations in intertidal and subtidal sediments were below the Sediment Quality Guidelines (SQGs). However, Cu and Ni concentrations exceeded these effect levels, indicating potential ecological effects on local benthic, pelagic and benthopelagic communities of the estuary. Linear relationships and coefficients for concentrations of heavy metals in surface water, intertidal and subtidal sediments during wet and dry seasons were calculated. Moreover, the results indicated a common anthropogenic pollution origin for the heavy metals. [ABSTRACT FROM AUTHOR]

Metal speciation data calculated by modeling could give useful information regarding the fate of metals in the rhizospheric environment. However, no comparative study has evaluated the relative accuracy of speciation models in this microenvironment. Consequently, the present study evaluates the reliability of free Cu ion (Cu2+ activity modeled by WHAM 6 and MINEQL+ 4.5 for 18 bulk and 18 rhizospheric soil samples collected in two Canadian forested areas located near industrial facilities. The modeling of Cu speciation was performed on water extracts using pH, dissolved organic carbon (DOC), major ions, and total dissolved Al, Ca, Cu, Mg, and Zn concentrations as input data. Four scenarios representing the composition of dissolved organic substances using fulvic, humic, and acetic acids were derived from the literature and used in the modeling exercise. Different scenarios were used to contrast soil components (rhizosphere vs bulk) and soil pH levels (acidic vs neutral to alkaline). Reference Cu2+ activity values measured by an ion-selective electrode varied between 0.39 and 41 nM. The model MINEQL+ 4.5 provided good predictions of Cu2+ activities [root-mean-square residual (RMSR) = 0.37], while predictions from WHAM 6 were poor (RMSR = 1.74) because they overestimated Cu complexation with DOC. Modeling with WHAM 6 could be improved by adjusting the proportion of inert DOC and the composition of DOC (RMSR = 0.94), but it remained weaker than predictions with MINEQL+ 4.5. These results suggested that the discrepancies between speciation models were attributed to differences in the binding capacity of humic substances with Cu, where WHAM 6 appeared to be too aggressive. Therefore, we concluded that chemical interactions occurring between Cu and DOC were key factors for an accurate simulation of Cu speciation, especially in rhizospheric forest soils, where high variation of the DOC concentration and composition are observed. [ABSTRACT FROM AUTHOR]

The investigation was carried out in the area of the Katowice Forest District (Upper Silesia -- Poland). For many years this area has been under permanent dust pollution influx. For discrimination of potentially contaminated areas with considerable high concentrations of technogenic iron particles and related heavy metals, soil magnetometry as a fast and simple proxy method was applied. The highest concentration of technoganic magnetic particles and trace elements was observed in a thin layer of the organic soil horizon. The magnetic anomalies observed were related to local sources of industrial and urban emission with high correlation to geochemical anomalies. [ABSTRACT FROM AUTHOR]

The aim of this paper was to determine the total content of titanium, barium, strontium, lithium and their fractions according to method by Zeian and Brümmer, as well as to compare the content of these elements in particular fractions in forest Luvisols. The sequential fractionation has shown different amounts of these elements in separated fractions. The highest amounts of the metals were determined in the residual fraction (F7). In mineral horizons the lowest amounts of titanium and lithium were separated in the following fractions: easily soluble (F1), exchangeable (F2), bound to MnOx (F3) and bound to organic matter (F4); barium -- in easily soluble (F1) and exchangeable (F2) fractions; strontium -- in bound to amorphic FeOx (F5) and bound to crystallinity FeOx (F6). [ABSTRACT FROM AUTHOR]

The aim of this work was to separate fractions of zinc and copper in forest Luvisols by three sequential extraction methods, and to compare the content of these metals separated in four fractions: easily soluble, exchangeable, bounded to organic matter and residual. The sequential fractionation of zinc and copper compounds was carried out according to the method by Tessier et al. modified by the authors, Zeien and Brtüanmer's method and Hedley's method in modification by Tiessen and Moir. In general, the highest amounts of both metals were determined in residual fraction, and the lowest -- in easy soluble and exchangeable ones. The statistical evaluation of results has revealed that the amounts of Zn and Cu in easy soluble, exchangeable, bound to organic matter and residual fractions are typically correlated with some properties of the analyzed Luvisols. [ABSTRACT FROM AUTHOR]

An empirical equation was developed to quantitatively describe heavy metal sorption in ternary systems of lead (Pb), copper (Cu) and cadmium (Cd). The three sorbants investigated were bentonite, forest soil and spruce bark. This multi-sorption equation is based on three assumptions: the relationship between sorption and initial heavy metal concentration fits a power curve; the presence of one heavy metal proportionately reduces the sorption curve of another heavy metal; and the competition between two heavy metals is independent of the presence of other heavy metals. The multi-sorption equation modeled sorption in ternary systems to a regression fit greater than 0.96. The data required for the equation were generated from a technically straightforward and quick laboratory program involving batch adsorption tests. [ABSTRACT FROM AUTHOR]

The article presents a study on the effects of metal concentrations on the adenosine triphosphate (ATP) and biomass-C in Gusum brass mill in south Sweden. The study uses soil samples from spruce forest which were examined in terms of basal respiration rate, substrate-induced respiration rate (SIR), and organic matter content. Results show that decreased ratio of ATP/biomass-C in metal polluted soils can be an indicator of a disturbed microbiological condition in soils.

To understand the role of the forest gaps and epiphytic mosses and lichens in the heavy metal cycles of forest ecosystems, the biomass, concentration, and storage of Cd, Pb, Cu, and Zn in epiphytic mosses and lichens on fallen logs and standing trees from the gap center to the closed canopy of an alpine forest ecosystem on the eastern Tibetan Plateau were investigated. Mosses were the dominant epiphytes on fallen logs and standing trees and contribute 82.1–95.1% of total epiphyte biomass in the alpine forest. A significantly higher biomass of epiphytic mosses and lichens was observed at the gap edge. The heavy metals concentration in mosses and lichens on fallen logs and standing trees varied widely with gap positions. Lower concentrations of Cd, Cu, and Pb were found in the mosses and lichens under the closed canopy, higher concentrations of Cd and Pb were detected in the mosses and lichens at the gap edge, and higher concentrations of Cu were found at the gap center. A significant difference in Zn concentration was observed between the mosses and lichens. No significant differences in Pb or Zn concentrations were observed in the mosses and lichens between the fallen log and standing tree substrates. Furthermore, the epiphytic mosses and lichens at the gap edge accumulated more Cd, Pb, and Cu, whereas the epiphytic lichens on the fallen logs and large shrubs at the gap center accumulated more Zn. In conclusion, gap regeneration accelerates the cycling of heavy metals in alpine forest ecosystems by promoting the growth of epiphytic mosses and lichens on fallen logs and standing trees at gap edges and increasing the concentration of heavy metals in these plants. [ABSTRACT FROM AUTHOR]

Heavy metal contents (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in 99 pairs of soil–rice plant samples were evaluated from the downwind directions of a large thermal power plant in Shaoguan City, Guangdong Province, China. Results indicate that there is a substantial buildup of As, Cd, Cu, Pb, and Zn in the predominant wind direction of the power plant. The significant correlations between S and heavy metals in paddy soil suggest that the power plant represents a source of topsoil heavy metals in Shaoguan City due to sulfur-rich coal burning emissions. Elevated Cd concentrations were also found in rice plant tissues. Average Cd (0.69 mg kg−1) and Pb (0.39 mg kg−1) contents in rice grain had exceeded their maximum permissible limits (both were 0.2 mg kg−1) in foods of China (GB2762-2005). The enrichment of Cd and Pb in rice grain might pose a potential health risk to the local residents. [ABSTRACT FROM AUTHOR]

The article discusses the study done to evaluate the extent of soil contamination with selected heavy metals including Zinc(Zn), Lead(Pb) and Copper(Cu), and the commutability of these contaminants into rhizome, a continuously growing rootstocks of the plant, Carex brizoides L. in oak-hornbeam habitats of European region. The result shows clonal plants – Carex brizoides, play a major role in the transfer of certain heavy metals in forest habitat.