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Fluxes of Cu, Zn, Pb, Cd, Cr, and Ni in temperate forest ecosystems
Abstract
The literature on the fluxes of six heavy metals in temperate forest ecosystems is reviewed. Special attention is given to wet and dry deposition and internal flux, to metal budgets for ecosystems and soils, to concentrations in aqueous compartments of the ecosystem and to speciation in soil solutions. Metal fluxes are discussed in relation to pollution load, soil type, tree species and land use. The mobility of Cu and Pb is strongly dependent on the solubility of organic matter. These metals are commonly accumulated in forest soils. Zinc, Cd and Ni are greatly influenced by soil acidity and are often lost in considerable amounts from acidified soils. Chromium is often at balance in forest ecosystems. Implications for metal solubility and budgets in forest soils are discussed in connection with an increase in soil acidification.
... Jensen and Svensmark 1989;Hanschmann and Opp 1993;Keller and Védy 1994;Johnson and Petras 1998;Hernandez et al. 2003;Bacon and Hewitt 2005;Steinnes and Friedland 2006). Forest ecosystems represent an efficient filter for toxic substances (Schlesinger and Reiners 1974;Binkley and Fischer 2012), due to the height and density of the tree canopies that intercept atmospheric dust by dry and wet deposition (Bergkvist et al. 1989). Consequently, although many large forest areas are often considered as natural ecosystems and only little impacted by anthropogenic contamination, forest soils may demonstrate surprisingly high surface concentrations of trace elements. ...
... The bulk of the atmospheric input measured nowadays would be of anthropogenic origin as far as heavy metals are concerned. Bergkvist et al. (1989) gave us a good insight of what is atmospheric deposition. "Metals are deposited to the tree canopy as wet and dry deposition. ...
... For all soils, a main pattern of leachability is associated with soil acidity (Bergkvist et al. 1989). In the literature, field studies under forests are quite rare and most often limited to the "purely organic mor horizons" (e.g. ...
Heavy metals in the environment continue to receive attention due to the greater understanding of their toxicological importance in ecosystems, agriculture and human health. Research on potentially harmful elements (PHEs) in life, agriculture and environmental sciences is extensively increasing since the last decades, owing to the larger consciousness of general population on the risks induced by anthropic activities. This book is dedicated to the occurrence and behaviour of PHEs in the different compartments of the environment, with special reference to soil as one of the most vulnerable ecosystems, and a precious resource with limited resilience capacity. Therefore, starting from the atmosphere (chapter 1), through the aquatic environment (chapter 2) and the different soil uses (chapters 3, 4), the book also encompasses all the anthropic systems where PHEs play a significant role (mine and urban areas, chapters 5, 6). The soil-plant relationships, and the element fluxes from soil to plant and the food chain, including an overview on soil remediation, are explored in chapters 7, 8. In the last part of the book, trace elements join the food safety (chapter 9) and the risk assessment (chapter 10), concluding with the potential risk to human health (chapter 11), which is the main purpose of the whole book: to ensure a safe environment and a good quality of life to new generations. The book provides new insight on the role and function of PHEs in the environmental and human health, following fundamental textbooks, without forgetting recent thousands of contributions from several scientific domains, not only soil science, but also plant physiology, biology, epidemiology, medicine, and in particular oncology. The book covers a list of the most environmentally important elements involved in environmental and human health. Key elements include: arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), selenium (Se). Emerging are those elements that have received less scientific attention, but nevertheless are of potential environmental concern, with reflection on human health.
... It has been stated that the main sink for metals coming from the atmospheric fallout is the litter (Bergkvist et al. 1989;Ettler 2015;Ginocchio et al. 2004)-likely due to litter being a good cation-complexing agent (Sauvé 2002). This fact is of great relevance in fruit tree productive systems, where Cu-based pesticides are applied through foliar spraying. ...
... Therefore, fungi must play a very important role in the decomposition and formation of DOC in fruit production systems. Bergkvist et al. (1989) conducted a review on metal fluxes in forest ecosystems. The authors concluded that the organic layer (litter) is the most important sink for metals coming from the atmospheric fallout, especially for copper, lead, and chromium. ...
... For all studies, the values are expressed as geometric mean, with the exception of Delgadillo et al. (2017), Konečný et al. (2014), andOorts et al. (2006) applications of cupric pesticides, there is no information on litter metal content, which allows the verification of its role as a sink for metals; however, in a preliminary monitoring carried out by our group in litter of apricot, kiwifruit, and orange trees fumigated with cupric pesticides (CuO), we demonstrated that total concentrations of Cu were between 158 (± 38) mg kg −1 and 646 (± 124) mg kg −1 , whereas, in non-fumigated vines, the total Cu content was only 27 (± 14) mg kg −1 (Fig. 2). When litter decomposition occurs, metals contained in plant tissues are mobilized through organic compounds, such as organic acids (Kabata-Pendias 2011), leaching from the A to the B horizon (Bergkvist et al. 1989). This is very relevant as in systems with a rich and even coverage of leaf litter, water that leaches through this layer can be loaded with DOC, enabling the formation of complexes with metals, mobilizing these contaminants into the lower soil layers (Hesterberg et al. 1992). ...
High soil copper may result in adverse effects on natural and agricultural systems. Copper-based pesticides have long been used for control of microbial diseases on fruit tree productive systems. Although copper is relatively safe from a human health management point of view, it can be accumulated in agricultural soils, affecting soil microbiota and litter degradation. The purpose of this review was to collect the available information to critically discuss the role that litter may play in fruit tree productive systems, in terms of copper incorporation into the soil, where this element is used as a pesticide. To achieve this objective, we focused our review on (1) soil contamination by copper-based pesticides in fruit production systems, (2) soil copper behavior, (3) effects of copper contamination on soil organisms, and (4) copper-litter relation in soil. From this review, we can suggest that (1) litter is the main sink of metals coming from atmospheric fallout because it is a good complexing agent of cations, (2) litter decomposition depends on its quality and in soil microbial activity, and (3) soil and litter microbial activity is negatively affected by soil copper enrichment. Thus, under uncontrolled applications of copper-based pesticides in fruit tree productive systems, copper soil enrichment will generate a decrease in microbial activity, diminishing litter breakdown and decreasing dissolved organic carbon formation. This process will also decrease the soluble copper incorporation into the soil; however, this assumption remains unevaluated.
... For example, several studies of boron fertilisation show its positive impact on tree productivity in boreal forests (Kilpeläinen et al. 2013;Riikonen et al. 2013). Soil organic matter decomposition and soil acidity are the main factors that improve the mobility of micronutrients in forest ecosystems (Bergkvist et al. 1989;Watmough et al. 2007). So far, the status of 19 micronutrients and their effect on growth after arable land is afforested are mainly studied in dense willow and poplar plantations (Laureysens et al. 2004;Dimitriou et al. 2012). ...
... The available Cu and Mn concentrations increased in the soil Ahorizon and for Cu also in the B-horizon. The mobility and availability of both these elements was probably favoured by the decreased soil acidity and decomposition of organic material (Bergkvist et al. 1989;Strobel et al. 2005;Watmough et al. 2007). High concentrations of Mn in the soil humus layer can decrease the stability of organic material (i.e., favour soil C release) (Berg et al. 2015). ...
... Kuivõrd A-horisondi boori sisaldus ei mõjutanud keskealistes istandikes puude kasvu, võib selle sisaldust lugeda endiselt piisavaks (IV). Omastatava mangaani sisaldus A-horisondis ning omastatava vase sisaldus A-ja B-horisondis suurenes (II), mida saab seostada nii omastatavate vormide vabastamisega orgaanilise aine lagunemisel kui ka pH väärtuse vähenemisega (Bergkvist et al. 1989;Strobel et al. 2005;Watmough et al. 2007). Mulla vasesislduse suurenemine oli seotud CEC-i ja mullaniiskusega, mis näitab savi võimet lahustunud vaske stabiilsemalt siduda. ...
... Emissions from anthropogenic activities, such as metal smelting, fossil fuel combustion, and spreading of phosphate fertilisers, are thought to be the cause for high levels of Cd in wood-combustion ashes (Narodoslawsky and Obernberger, 1996). Cadmium-containing emissions from these activities are transported to and then deposited in forest ecosystems (Bergkvist et al., 1989;Hernandez et al., 2003) that provide the biomass for wood-combustion processes. Chromium can make its way into forests and therefore wood-combustion ashes via similar pathways to Cd (Bergkvist et al., 1989;Hernandez et al., 2003), however, there are other possible pathways for Cr to ashes. ...
... Cadmium-containing emissions from these activities are transported to and then deposited in forest ecosystems (Bergkvist et al., 1989;Hernandez et al., 2003) that provide the biomass for wood-combustion processes. Chromium can make its way into forests and therefore wood-combustion ashes via similar pathways to Cd (Bergkvist et al., 1989;Hernandez et al., 2003), however, there are other possible pathways for Cr to ashes. Another pathway is contamination of ashes and/or unburned biomass with disintegrating metallic equipment, e.g. ...
This study assesses the potential of thermal processing for detoxification of wood-combustion ashes that contain high levels of Cr and Cd. Thermal treatment (1000 °C) of bottom ash and fly ash in an oxidising gas (air) atmosphere resulted in: low volatilisation of Cd and most other heavy metals, oxidation of Cr in the ashes to Cr (VI), and, in the case of the fly ash, significantly increased leaching of Cr and Mo. Thermal treatment in a nitrogen atmosphere resulted in local reducing conditions due to oxidation of ash-derived carbon to CO (g). Thermal treatments in this atmosphere and in a reducing atmosphere consisting of 10 % H2 and the balance N2 detoxified the ashes in at least two ways: (i) by substantially removing Cd, Pb, Bi, Tl, and, in the case of the fly ash, Zn from the ashes by volatilisation; and (ii) by thermal reduction of Cr (VI) in the ashes. There was at least a 100-fold reduction in the leaching of total Cr from both the bottom ash and the fly ash following the thermal treatments in reducing conditions. Chromium only leached from the detoxified bottom ash to a significant extent in acidic conditions (pH < 4).
... Forests among other terrestrial ecosystems play a key role in hydrological and biogeochemical cycles. Major and trace elements (MEs and TEs) as a part of these cycles are transporting through forest ecosystem compartments (Bergkvist et al. 1989;Tyler and Olsson 2001). In this regard, forest soils act as a main pool for accumulation and transformation of different substances. ...
... Cesium accumulates in organic horizon during litter decomposition and its mobility decreases in neutral and alkaline environment (Rafferty et al. 2000). Many investigations have showed that the solubility of Co, Ni, and Zn decreases in neutral and alkaline soil pH (Bergkvist et al. 1989;Liodakis et al. 2009;Pereira et al. 2012). Interestingly, concentrations of Ni in the studied soils were even lower than that in world's Cambisols. ...
Purpose
Forest ecosystem acts as a significant sink and source of elements; however, the dynamics of trace elements (TEs) in soils of boreal zone are still poorly characterized. Data on relationships of TEs, major elements (MEs), soil properties, and parent rock geochemistry in boreal forest of Northeast Asia are scarce. Therefore, the objectives of this study were to evaluate the origination of TEs in forest soils and identify soil properties and ecosystem processes controlling accumulation and profile distribution of TEs.
Materials and methods
Dystric Cambisols and underlying parent rocks have been sampled within hilly landscape covered by Gmelin larch (Larix gmelinii (Rupr.) Rupr.) forests in Amur region (Russia). This paper considers 10-selected soil characteristics, total concentrations of 19 TEs, and 10 MEs measured by ICP-MS and RFA analysis. Factor analysis has been employed to highlight underlying relationships hidden in a complex data of element concentration and soil characteristics. Origination of TEs was assessed by using an enrichment factor (EF) considering concentration of TEs in soil in comparison to underlying parent rocks using Ti as a reference element.
Results and discussion
A group of biophile Zn, Mo, Sn, and Pb were enriched in the upper soil horizon, and depleted in mineral compared to parent rocks. Beryllium, Sc, Cr, Cu, Ga, Ge, Ta, Th, and U were depleted in both horizons. Ni and Cs show highest enrichment in both studied soil horizons. Frequently occurring forest fires affect soil characteristics and TEs dynamic only in the upper part of soil profile. Factor analysis revealed potential effect of exchangeable Na and soil pH on accumulation of the elements in the upper horizon, as a result of ash deposition by fire.
Conclusions
The studied TEs primarily originate from underlying parent rocks. Accumulation versus leaching of TEs in Dystric Cambisols might be element specific and affected by fire-derived ash. Our work shows that the upper horizon of forest soils could act as a significant sink of group of TEs. Therefore, long-term observations of TEs dynamic in soil profiles are needed to elucidate biogeochemical cycles in frequently burned forests of Northeast Asia. The present study for the first time has established an important wide data set of TEs concentration in Dystric Cambisols of natural boreal forests in the Russian Far East.
... Some heavy metals, e.g. Zn and Cu, are more mobile in ecosystems than others (Bergkvist et al. 1989). In the current study, the root uptake factor showed higher mobility of Zn and Cu, but also Cd. ...
... In the current study, the root uptake factor showed higher mobility of Zn and Cu, but also Cd. The mobility of heavy metals depends on several soil-related factors, such as pH, level of dissolved organic carbon content and the presence of organic ligands in leachate (Bergkvist et al. 1989). PH <5.5-6.0 increases heavy metal leaching and availability; hence a soil pH ˃6 decreases the availability of some heavy metals, e.g. ...
Estonia is the only country in Europe that is actively mining oil shale. Oil-shale-burning power plants have been and still are the main sources of heavy metals in Estonia. In order to establish how coniferous ecosystems are affected by Zn, Cu, Cr, Ni, Cd and Pb, heavy metal content in current-year and older needles, in litterfall needles and litterfall miscellaneous fraction, in fine roots and in soil organic horizons was analysed at six coniferous stands of ICP Forests and ICP Integrated Monitoring networks. Root uptake, translocation and accumulation indexes were calculated for each heavy metal. The highest concentrations of most of the heavy metals were found in the soil organic horizons, with the exception of Zn and Cu, the highest concentrations of which were found in fine roots. The results showed that concentrations of the rest of the heavy metals (Cr, Ni, Cd and Pb) were also higher in fine roots compared to other plant material. Significant correlations between the concentrations in soil organic horizons and fine roots indicated that heavy metals had accumulated in the soil organic horizon over time and, in some cases, they may have been transported to above-ground living biomass of coniferous trees.
... Trees in the forest are a classic example of ecosystem engineers (Jones et al., 1994) that significantly modify the physical and chemical environment and thereby shape the spatial structure of forest communities. A well-known fact is that tree crowns redistribute atmospheric precipitation and alter its chemical composition (Uchvatov and Glazovskii, 1984;Bergkvist et al., 1989;Frost, 2003, 2006;Keim et al., 2005;Staelens et al., 2006;Andre et al., 2011;Bialkowski and Buttle, 2015;Frischbier and Wagner, 2015;Levia and Germer, 2015) and produce an effect on the light, thermal, and wind regimes of habitats (Ipatov and Kirikova, 2001), the moss and herb-dwarf shrub vegetation layers, and tree stand regeneration (Coates, 2000;Kryshen', 2000;Lebedeva et al., 2005;Miller et al., 2006). All this has influence on morphological, physicochemical, and biological properties of soils (Zinke, 1962;Mina, 1967;Karpachevskii, 1981;Seiler and Matzner, 1995;Rhoades, 1997;Dmitriev et al., 1999;Pishchulin, 2009, 2011;Ma et al., 2014). ...
... 29.1*** 39.9*** 1.8 ns 9.4*** Cd 126.4*** 46.1*** 20.4*** 66.3*** 6.3*** 21.1*** Zn 143.2*** 49.6*** 21.4*** 68.2*** 6.9*** 26.5*** Differences between individual trees (df 2 = 9) Ginocchio et al., 2004;Blagodatskaya et al., 2008). The majority of authors explain this descending concentration gradient by increased input of chemical elements with precipitation and aerosols that are intercepted by tree crowns and then reach the ground as throughfall and stemflow (Bergkvist et al., 1989;Frost, 2003, 2006;Bialkowski and Buttle, 2015;Levia and Germer, 2015), enrichment of stemflow with elements leached out of foliage and bark (Mina, 1967;Frost, 2003, 2006), and heterogeneous distribution of litterfall with its prevailing accu-mulation under tree crowns, at least in conifer forests (Hirabuki, 1991). ...
An analysis is made of the effect of large spruce and birch trees on the spatial pattern of the fields of heavy metal concentrations (Cu, Pb, Cd, Zn) and pH in the forest litter formed in tree stands exposed to long-term pollution with emissions from the copper smelter in Revda, Sverdlovsk oblast. The fields formed by trees growing in the background area have a regular spatial structure: the concentrations of elements decrease with increase in the distance from the tree trunk to the edge of canopy gap, with the position of sampling point relative to the trunk accounting for more than half of total variance. In polluted areas, the regular component of the field structure is very weakly expressed, and the main role is played by higher-order heterogeneity related to the mosaic pollution pattern on the scale of tens to hundreds of meters.
... What's more, solubility and bioavailability of many metals is connected with acidity of solutions in which they are present. Basing on the examples on soil solutions Bergkvist et al. (1989) correlated the dependence between pH and the concentration of selected metals. A rapid increase in solubility and bioavailability of metals below the critical pH value of aqueous solutions (4-4.5 in the examined soiled samples). ...
... One of the crucial factors which govern colonization processes and limit the occurrence of epiphytes is air humidity (Bergkvist et al. 1989). A city is an example of anthropogenic environment in which humans influence climate indirectly (Dudek et al. 2008). ...
Katowice is the largest city within the Upper Silesian Industrial District (S Poland). The investtigation conducted in this town earlier (1998-2000) showed limited number of epiphytic species. Recent study showed significant increase in number of localities of obligate epiphytes (mainly from the genera Orthotrichum and Ulota). They colonize mainly the edges of strongly urbanized areas bordering forest complexes and larger parks. This paper is an attempt to answer the question as currently in Katowice shape the main factors determining the occurrence of epiphytes. Crucial factors which govern epiphytes colonization processes in urban areas have been confirmed: bark chemistry (taking into account natural attributes and the influence of pollution) and air humidity. The preference of epiphytes towards inhabited phorophytes was confirmed as well. The most commonly and abundantly inhabited species were poplar and willow trees (which have a higher pH of bark).
... Woody species have included autumn olive (Elaegnus angustifolia), Scotch pine (Pinus sylvestris), red pine (Pinus resinosa), white pine (Pinus strobus), blafi locust (Robinia pseudoacacia), Virginia pine (Pinu svirginiana) and short leaf (Pine echinata). Pines tend to acidify soils which may increase mobility of heavy metals like Cd and Zn if they are present (Bergkvist et al., 1989). Paper birch (Betula papyrifera) has been shown to accumulate twice as much Cu as many other trees (Lepp and Dickson, 1998). ...
... FFONLY, forest floor only control; FFONLY-NA, sodium azide added with no forest floor added. solution was too low and indiscernible from the background for the range typically observed in soils in point-source contaminated and uncontaminated soils (Bergkvist et al., 1989). ...
As northeastern forests experience increased temperatures and fluctuations in precipitation patterns, montane soils will lose forest floor (Oi, Oe, Oa horizons) formation and their associated ecosystem services. Here, we conducted comparative laboratory soil column experiments to examine the effects of forest floor on sourcing and weathering of macroelements (Al, Si), macronutrients (Ca, Mg, P), and micronutrients (Cu and Zn) from two contrasting soils: a supraglacial‐till Inceptisol (Mt. Moosilauke, NH) and colluvium Ultisol (Lesesne State Forest, VA). Forest floor addition caused a significant increase in the leaching of Ca, Mg, and Mn in the two soils. The forest floor only control leachate indicates the two mineral soils were net accumulators of Al, Si, P, Cu, and Zn from the forest floor. Using partition coefficient, Kd, values, leachate Ca and Mg could be sourced directly from the forest floor traversing the soil column. We aimed to assess the biotic influence on element release from soil using a Na azide treatment to suppress microbial activities. Under Na azide treatments, Al, Ca, Mg, Mn, and Cu leachate decreased significantly for both soils, but Na azide also did not affect or increased leachate Si, P, Cu, and Zn for the Lesesne soil. We attribute the effects from Na azide to changes in pH, dissolved organic carbon, and oxidation‐reduction potential as opposed to suppression of microbes. Thus, our results suggest that the loss of the forest floor will reduce the storage of nutrients in the mineral soil, even across varying parent materials.
... Dissolved OM was found to enhance the mobility of Ni and Cu, whereas Zn mobility was not modified, in soil [13]. Leaching of Cu was found to increase with decline in pH, with the lowest mobility occurring at pH 5-7 [14,15]. [16] concluded that it was not feasible to make long-term predictions based on short-term standardized laboratory tests. ...
Heavy metal contamination has increasingly become an environmental problem. While it is found in soils naturally through processes of weathering of parent materials , it is the anthropogenic activities that create the greatest threat. A study was conducted to investigate the vertical distribution of heavy metals in soils after over 50 years of sewage sludge application. Soil samples were collected at 10 cm intervals to a depth of 50 cm from five treated transects and a control. The soils were analyzed for zinc, copper, lead, nickel, cadmium, arsenic and chromium. The concentration of all the metals was higher in the treated soils compared to the control. The results were compared with two parameters: the total maximum thresholds (TMT) and maximum permissible limits (MPL). The TMT is the concentration of the metal beyond which the risk to the environment is unacceptable, while MPL is the concentration beyond which further waste disposal is prohibited. Zinc, chromium, lead and cadmium were above maximum permissible limits, in treated soils. High concentrations of all the metals, including Pb, and organic carbon were measured down to 40-50 cm depth. Only Cd (and Pb only in transect 2) was above the maximum permissible limits beyond the 20-30 cm depth.
... With current globalization and industrialization, an increasing amount of potentially toxic elements including copper (Cu), nickel (Ni), lead (Pb), and chromium (Cr) has been generated, becoming of great concern due to the adverse effects on health and environment (Kubier et al., 2019;Li and Achal, 2020;Pourret and Hursthouse, 2019). The hazardous chemicals released are involved in environmental processes including bioaccumulation, food contamination, and widespread ecological exposure (Bergkvist et al., 1989;Hou et al., 2020), leading to a larger-scale risk spread. Various techniques including physico-chemical remediation, bio-and especially phyto-remediation have been used to reduce the soil metal concentrations in various countries (He et al., 2020;Li et al., 2019;Wang et al., 2021;Zhai et al., 2018). ...
Microbially induced carbonate precipitation (MICP) is a biomineralization process that has various applications in environmental pollution remediation and restoration of a range of building materials. In this study, a ureolytic bacterium, Lysinibacillus sp. GY3, isolated from an E-waste site, was found as a promising catalyst for remediation of heavy metals via the MICP process. This bacterial isolate produced significant amounts of urease and showed a great persistence in immobilization of potentially toxic elements. A reference ureolytic strain, Bacillus megaterium VS1, was selected in order to compare the efficiency of Lysinibacillus sp. GY3. Study on urease localization indicated 80% more urease activity secreted extracellularly as for Lysinibacillus sp. GY3 compared to B. megaterium VS1. From the investigation on effects of metals on both intra- and extra-cellular urease, it was clear that Lysinibacillus sp. GY3 produced the most stable urease under conditions of metal pressure, especially retaining more than 70% activity in the presence of 1 g/L Pb²⁺ and Zn²⁺. These results suggest that this isolated microorganism could be promisingly introduced in the MICP process to stabilize complex heavy metal pollutions, with reference to the regulating ability under harsh conditions to stabilize urease activity. This species is so important both for its biological features and environmental impacts. In addition, the present study will bring new insight in the field of metal remediation coupled with enzyme engineered biotechnology.
... Up to 61% of the variability in Zn K d in the FH was explained by the regression equation using pH and OM, followed by 43% of Al K d variability which was explained by pH alone. Within the 0-5 cm mineral layer, pH again had a greater influence on metal K d values compared with OM, apart from Cu, which was strongly and solely influenced by OM, which coincides with the tendency of Cu to complex with OM (Bergkvist et al., 1989;Wenzel, 2000), while no regression equation was attained for Pb due to limited sample size. Partitioning of Ni, Al, Mn, and Zn in mineral soil were most strongly influenced by pH. ...
Limestone is a common amendment used to counteract soil acidity and metal pollution. Understanding the legacy effects of a one-time soil limestone application and subsequent afforestation is needed to evaluate the long-term success of remediation efforts. In this study, soil and tree chemistry were measured across 15 limed sites that were treated and planted 14 to 37 years ago in Sudbury, Ontario, along with two untreated sites. Soil pH and exchangeable base cation (calcium (Ca) and magnesium (Mg)) concentrations were generally elevated especially in surface organic [FH] horizons up to 37-years post limestone treatment. High site-to-site variation however, obscured clear patterns over time and base cation mass budgets were generally unable to account for the mass of added Ca and Mg. Metal partitioning (Kd) in soil was most influenced by soil pH rather than organic matter (OM) showing that metal availability increases as liming effects fade. This study shows that the legacy effects of soil liming can persist for several decades and are most apparent in the forest floor (FH), but legacy effects are quite modest, and it is likely that a considerable amount of limestone has been lost through erosion.
... Leaf litter is one of the main sinks of soil trace elements from the atmospheric fallout to (Bergkvist et al. 1989;Ginocchio et al. 2004;Ettler (2015), likely due to its cationcomplexing capacity (Sauvé 2002). For this reason, Schoffer et al. (2020) proposed that leaf litter can exert a protective role against the incorporation of Cu into the soil in fruit tree orchards treated with Cu-based pesticides. ...
This study assessed the capacity of leaf litters to adsorb copper ions applied as a copper-based pesticide. Leaf litters of two fruit tree species with different lignin/N ratios were examined to determine their protective role against the incorporation of Cu into soil. A leaf litter Cu-adsorption capacity assay and a degradation assay were performed using table grape (lignin/N = 2.35) and kiwi (lignin/N = 10.85) leaf litters. Table grape leaf litter had a significantly (p = 0.001) higher Cu-adsorption capacity (15,800 mg kg−1) than kiwi leaf litter (14,283 mg kg−1). Following leaf litter degradation, significant differences (p = 0.011) were observed in the release of Cu from Cu-enriched leaf litter into soil, showing that kiwi litter has a greater protective effect against the incorporation of Cu into soil, regardless of the amount of Cu applied. This protective role is reflected in a significantly higher (p = 0.015) Cu concentration in table grape soil (41.71 ± 2.14 mg kg−1) than in kiwi soil (35.87 ± 0.69 mg kg−1). Therefore, leaf litter with higher lignin/N ratio has greater protective role against copper incorporation into soil.
... The critical loads for lead (ecosystem related) in the example would increase by up to 169% compared to the CL(Pb) eco determined here if the 90 percentile of lead concentrations according to Knappe et al. [54] were applied, which in this case are 300% higher than those used here. In particular, the Cu, Cr and Ni contents in the stem wood of typical tree species in Germany are significantly dependent on the concentration in the soil [59]. Therefore, in this study, the low values published by Jacobsen et al. [32] were included in the CL calculation, which corresponds to the worst case. ...
Background
The critical values for heavy metal fluxes for protecting the human health and ecosystem’s integrity in Germany, especially the Federal Immission Control Act (BImSchG in Gesetz zum Schutz vor schädlichen Umwelteinwirkungen durch Luftverunreinigungen, Geräusche, Erschütterungen und ähnliche Vorgänge (Bundes-Immissionsschutzgesetz-BImSchG), 1974/2020) with its implementing ordinances (especially the 39th BImSchV in Neununddreißigste Verordnung zur Durchführung des Bundes-Immissionsschutzgesetzes Verordnung über Luftqualitätsstandards und Emissionshöchstmengen vom 2. August 2010, zuletzt geändert durch Art. 2 V v. 18.7.2018 I 1222, 2010, 2018), the Federal Soil Protection Ordinance (BBodSchV in Bundes-Bodenschutz- und Altlastenverordnung (BBodSchV) (GBBl. I S. 1554 vom 12. Juli 1999, zuletzt durch Artikel 3 Absatz 4 der Verordnung vom 27. September 2017 (BGBl. I S. 3465) ge-ändert, 1999/2015) and the Technical Instructions on Air Quality Control (Luft in Erste Allgemeine Verwaltungsvorschrift zum Bundes–Immissionsschutzgesetz (Technische Anleitung zur Reinhaltung der Luft – TA Luft), 2002), were analysed, assessed with regard to the possibilities and applicability of the risk assessment, and were prepared for evaluation in comparison to the respective atmospheric deposition modelled with the chemical transport model LOTOS-EUROS. For a comparison of the critical values, the critical loads for cadmium, lead and mercury inputs were updated for Germany on a scale of 1:1 Mio, and critical loads for additional heavy metals (arsenic, copper, zinc, chromium and nickel) were computed, respectively. Due to the methodological differences of their derivation, the critical values of the individual regulations are only conditionally comparable to one another and to the critical loads. Sometimes major differences exist due to different levels of protection, various protective goods and the effect relationship. Only with the critical load calculations, inputs and outputs can be balanced.
Results
For two unregulated metals (thallium and vanadium) a preliminary rough estimate of the risk of inputs in the receptors was provided as a calculated balance for in- and acceptable outputs. The uncertainty analysis shows, that the highest deviations occurred in the metal contents in plants used to calculate the output through the harvesting of the biomass. The critical load calculation has the highest sensitivity to changes in the pH value. The critical loads for heavy metal fluxes for protecting the human health (CL(M) drink ) and ecosystem’s integrity CL(M) eco ) for arsenic, nickel, zinc and chromium were not exceeded in Germany for 2009–2011. CL(M) drink and CL(M) eco are exceeded by Hg and Pb inputs, especially in the low rainfall regions of Germany (Brandenburg, lowlands of Saxony-Anhalt, Leipzig Bay, Ruhr valley) with wood vegetation; in addition CL(Cu) eco is exceeded by copper deposition 2010 in the area surrounding Berlin and in the Ruhr valley. The critical loads for cadmium for the protection of drinking water CL(Cd) drink and for the protection of human food from wheat products CL(Cd) food are not exceeded in the German data set due to atmospheric deposition in 2010, but in the worst-case scenario the maximum atmospheric deposition in 2010 could exceeded the lowest CL(Cd) drink and CL(Cd) food .
Conclusions
That assessment of risks was based on deposition from the atmosphere, which represents only a fraction of the inputs compared to the inputs from the use of fertilisers and other sources. This study suggests the conclusive recommendation to methodically deepen and broaden the assessment and evaluation of atmospheric deposition. This is especially true for the spatial validation and specification of exposure for ecosystem types.
... Hence, for our study period, the sites EPC08, EPC63 and SP11 were highly impacted by dry deposition (Table 1) compared to the sites HET30, SP05, SP38 and SP68 with low dry deposition fluxes (NTF(Na) < 1 kg ha À1 yr À1 ). Although conifers are generally more efficient in trapping dry deposition than deciduous trees because of their aerodynamic properties and constant leaf area throughout the year (Bergkvist et al., 1989), in our study sodium enrichment (and thus the dry deposition flux) did not solely depend on functional tree types (Wilcoxon test, p ¼ 0.699). Furthermore, rainfall amount can impact dry deposition by their washing-off from canopy, but here no link between NTF(Na) and RF amount was found (Spearman's correlation, p ¼ 0.492). ...
Estimation of the canopy influence on atmospheric inputs of iodine (I), selenium (Se) and caesium (Cs) in terrestrial ecosystems is an essential condition for appropriate biogeochemical models. However, the processes involved in rain composition modifications after its passage through forest canopy have been barely studied for these elements. We monitored I, Se and Cs concentrations in both rainfall and throughfall of fourteen French forested sites throughout one year, and estimated dry deposition and canopy exchange fluxes for these elements, as well as speciation of I and Se. Comparison of rainfall and throughfall elemental composition highlighted an important impact of forest canopy on both (i) concentrations and fluxes of I, Se and Cs, and (ii) I and Se species. For the three elements, most of their throughfall concentrations were higher than corresponding rainfall. The increase of throughfall elemental fluxes was mostly due to dry deposition for I and Se although the canopy exchange model revealed some sorption within the canopy in most cases; for Cs, foliage leaching was most influencing. Regarding speciation, iodine species in rainfall were highly modified by forest canopy with an important increase of unidentified I proportion in throughfall (on average 49 and 82% in rainfall and throughfall, respectively), possibly due to washoff of dry deposition and/or to transformation into organic forms. Similarly, while rainfall was composed of 26–54% of inorganic Se, inorganic species were undetectable in throughfall. This dataset represents key information to improve modelling of I, Se and Cs cycling within forest ecosystems.
... 26) um bis zu 169 % gegenüber den hier ermittelten CL(Pb) eco erhöhen bei Anwendung der 90er-Perzentile der Bleikonzentrationen nach Knappe et al. (2008), die in diesem Fall 300 % höher liegen als die hier verwendeten. Insbesondere für die Cu-, Cr-und Ni-Gehalte im Derbholz der typischen Baumarten in Deutschland gilt eine signifikante Abhängigkeit von der Konzentration im Boden (Bergkvist et al. 1989). Deshalb wurden in dieser Studie die niedrigen, von Jacobsen et al. (2002) ...
de Hintergrund und Ziel. Kritische Eintragsraten (Critical Loads) sind quantitative Schätzungen der Exposition von Ökosystemen einschließlich des Menschen gegenüber einem oder mehreren Schadstoffen, unterhalb derer nach heutigem Kenntnisstand nicht mit signifikanten schädlichen Auswirkungen zu rechnen ist. Wenn die atmosphärische Deposition die kritische Belastung eines Schadstoffs für ein Ökosystem überschreitet, können toxikologische Auswirkungen induziert werden. Deshalb werden kritische Eintragsraten verwendet, um Ökosysteme und die menschliche Gesundheit vor Luftverschmutzung zu schützen. Ziel dieser Untersuchung war es, die in Deutschland verfügbaren Critical Loads von Schwermetall‐Flüssen zum Schutz der menschlichen Gesundheit und der Integrität von Ökosystemen zu bewerten. Dabei lag ein Schwerpunkt auf der Betrachtung der Anwendbarkeit der Critical Loads in ökologischen Risikoabschätzungen durch Vergleich mit der atmosphärischen Deposition, die mit Hilfe des Stofftransportmodells LOTOS‐EUROS modelliert wurde.
Methoden und Ergebnisse. Zu diesem Zweck wurden die Critical Loads für Cadmium‐, Blei‐ und Quecksilbereinträge für Deutschland im Maßstab 1:1 Mio. aktualisiert bzw. Critical Loads für zusätzliche Schwermetalle (Arsen, Kupfer, Zink, Chrom und Nickel) berechnet. Aufgrund der methodischen Unterschiede ihrer Ableitung sind die Grenzwerte mehrerer Umweltschutzvorschriften untereinander und mit den Critical Loads nur bedingt vergleichbar. Die zum Teil großen Unterschiede bestehen aufgrund unterschiedlicher Schutzniveaus, verschiedener Schutzgüter und der Wirkungszusammenhänge. Für zwei unregulierte Metalle (Thallium und Vanadium) wurde eine vorläufige grobe Abschätzung des Risikos von Einträgen in die Rezeptoren als berechnete Bilanz für Ein‐ und Austräge vorgelegt. Die Unsicherheitsanalyse zeigt, dass die höchsten Abweichungen bei den Metallgehalten in den Pflanzen auftraten, die zur Berechnung des Outputs durch die Ernte der Biomasse verwendet wurden. Die Berechnung der Critical Loads weist die höchste Empfindlichkeit gegenüber Änderungen des pH‐Wertes auf. Die Critical Loads für Schwermetall‐Flüsse zum Schutz der menschlichen Gesundheit (CL(M)drink) und der Integrität des Ökosystems (CL(M)eco) für Arsen, Nickel, Zink und Chrom wurden in Deutschland für den Zeitraum 2009‐2011 nicht überschritten. CL(M)drink und CL(M)eco werden durch Hg‐ und Pb‐Einträge überschritten, insbesondere in den niederschlagsarmen Regionen Deutschlands (Brandenburg, Tiefland von Sachsen‐Anhalt, Leipziger Bucht, Ruhrtal) mit Waldvegetation. Darüber hinaus wird CL(Cu)eco durch Kupferablagerungen 2010 in der Umgebung von Berlin und im Ruhrtal überschritten. Die Critical Loads für Cadmium zum Schutz des Trinkwassers CL(Cd)drink und zum Schutz der menschlichen Nahrung vor Weizenprodukten CL(Cd)food werden im deutschen Datensatz 2016 durch atmosphärische Deposition 2010 nicht überschritten, aber im schlimmsten Fall könnte die maximale atmosphärische Deposition 2010 die niedrigste CL(Cd)drink und CL(Cd)food überschreiten. Diese Risikobewertung basiert auf der Deposition aus der Atmosphäre, die nur einen Bruchteil der Einträge im Vergleich zu den Einträgen durch den Einsatz von Düngemitteln darstellt.
Schlussfolgerungen. Die Ergebnisse legen die Empfehlung nahe, die Beurteilung und Bewertung der atmosphärischen Ablagerung methodisch zu vertiefen und zu erweitern. Dies gilt insbesondere für die räumliche Validierung und Spezifizierung der Exposition für verschiedene Ökosystemtypen.
Abstract
en Background and goal. Critical loads are quantitative estimates of the exposure of ecosystems, including humans, to one or more pollutants below which, according to current knowledge, no significant adverse effects are expected. If atmospheric deposition exceeds the critical load of a pollutant for an ecosystem, toxicological effects may be induced. Critical loads are therefore used to protect ecosystems and human health from air pollution. The aim of this study was to evaluate the critical loads of heavy metal fluxes available in Germany to protect human health and the integrity of ecosystems. The focus was on the applicability of the critical loads in ecological risk assessments by comparison with atmospheric deposition, which was modelled using the LOTOS‐EUROS mass transport model.
Methods and results. For this purpose, the critical loads for cadmium, lead and mercury inputs for Germany were updated on a scale of 1:1 million and critical loads for additional heavy metals (arsenic, copper, zinc, chromium and nickel) were calculated. Due to the methodological differences in their derivation, the limit values of several environmental protection regulations are only partially comparable with each other and with the critical loads. The differences, some of which are large, are due to different levels of protection, different goods to be protected and the interrelationships of effects. For two unregulated metals (thallium and vanadium) a preliminary rough estimate of the risk of inputs into the receptors was presented as a calculated balance for inputs and outputs. The uncertainty analysis shows that the highest deviations in metal contents occurred in the plants used to calculate the output from harvesting the biomass. The calculation of the critical loads shows the highest sensitivity to changes in pH. The critical loads for heavy metal fluxes for the protection of human health (CL(M)drink) and the integrity of the ecosystem (CL(M)eco) for arsenic, nickel, zinc and chromium were not exceeded in Germany for the period 2009‐2011. CL(M)drink and CL(M)eco are exceeded by Hg and Pb inputs, especially in the low‐precipitation regions of Germany (Brandenburg, lowlands of Saxony‐Anhalt, Leipzig Bay, Ruhr Valley) with forest vegetation. In addition, CL(Cu)eco is exceeded by copper deposition in 2010 in the vicinity of Berlin and in the Ruhr valley. The critical loads for cadmium for the protection of drinking water CL(Cd)drink and for the protection of human food from wheat products CL(Cd)food are not exceeded in the German dataset 2016 by atmospheric deposition in 2010, but in the worst case the maximum atmospheric deposition could exceed the lowest CL(Cd)drink and CL(Cd)food in 2010. This risk assessment is based on atmospheric deposition, which represents only a fraction of the inputs compared to the inputs from the use of fertilizers.
Conclusions. The results suggest the recommendation to methodically deepen and broaden the assessment and evaluation of atmospheric deposition. This applies in particular to the spatial validation and specification of exposure for different ecosystem types.
... The enrichment of snow with dissolved forms of Zn and Mn possibly happens in situ as a result of leaching of dust particles under acidic conditions. It has been shown that the mobility of Zn increases as the pH level decreases (Bergkvist et al. 1989). Numerator-min-max; denominator-geometric mean *In more than 50% of samples, the content was lower than the detection level To verify the metal deposition rates and to estimate the ecological risk level within our study area, we compared our data with data from other regions. ...
In order to evaluate the level of atmospheric pollution in the north of Western Siberia, we studied the composition of urban snow in the vicinity of the Tazovsky settlement as well as in the area of Zapolyarnoye—the largest natural gas field in Russia in terms of a total extraction volume. Our results indicate that anthropogenic activities have caused an increase in electric conductivity and pH values of meltwaters. Concentrations of dissolved and particulate forms of trace elements (Fe, Mn, Ni, Cr, Cu, Pb, Zn, and Cd) were determined using atomic absorption spectroscopy. Dissolved forms of Cd, Zn, and Mn and particulate forms of Cu, Fe, and Ni prevailed in meltwaters of background territories. Human-affected territories were characterized by a predominance of particulate forms of trace elements (except Cd), which indicated increased dust deposition rates. For Cu, Mn, and Fe, mean values of contamination factor (CF) exceeded background levels by 4.4, 4.7, and 6.6 times, respectively. At some sampling sites, concentrations of trace elements exceeded background levels by 10–111 times. The concentration of Zn in our study area was higher than those in other oil and gas fields located in polar and boreal regions. The Cd concentration in the vicinity of the Tazovsky settlement was higher than those in other cities of Western Siberia. The data obtained in the present study on concentrations of soluble and particulate forms of trace elements in snow will be valuable for environmental protection in Russia’s Arctic territory.
... Adjusted R 2 = 0.67 Adjusted R 2 = 0. Metal concentrations decrease at the same rate with increasing distance from the former emission source, whatever the land use, but they differ according to land use at a given distance arable soil and permanent grassland: 32 and 30 g m −3 for Pb and 89 and 85 g m −3 for Zn (Fernandez et al. 2007), whereas in the acid forest soil (Fig. 1), the Pb stock was higher, 38 g m −3 , but the Zn stock was about three times lower, only 30 g m −3 (Baize and van Oort 2014). These findings clearly highlighted the filter effect of the canopy, intercepting more atmospheric dust, and the strong leaching of Zn under acid soil conditions (Bergkvist et al. 1989), and were consistent with model 2. To estimate the total amount of Zn deposited on the forest soil, we hypothesized that the original Zn/Pb ratio of airborne deposition could be best approximated with the higher Zn/Pb values observed for arable soils, since metal movement was supposed limited due to recurrent liming and fertilization practices. Using a Zn/Pb value of 4 (Fig. 6a), with a Pb stock of 38 g m −3 , the Zn stock should have reached about 160 g m −3 , if no Zn downward migration had occurred, instead of the 30 g m −3 actually measured. ...
Zinc (Zn) and lead (Pb) concentrations were measured in 173 samples collected in soils under forest, wetland, and arable land around a Zn smelter plant that stopped activity in the 1960s. The adopted sampling strategy consisted in collecting 0–30-cm-depth samples from all soils, tilled or not, in order to harmonize the analyzed soil volume to that of plowed soils. Airborne deposition was modeled as a function of the distance from the pollution source and of land use. The Zn/Pb concentration ratios in the surface layer remarkably contrasted 3–4, 1.5–2, and ~ 0.5 for arable, wetland, and forest soils, respectively, independently from the distance to the emission source, while total Zn and Pb concentrations, taken separately, were only slightly discriminant. For metal pollution sites originating from former industrial activity, Zn/Pb concentration ratios determined on relevant soil samples represent a powerful indicator that provides easy and rapid information in real field conditions on time-related input/output dynamics of mobile and less-mobile metal pollutants, and hence, on interactions between pollutants and soils under different land use conditions.
... The structure of forest BGCs determines the pattern of their soil properties [6]. A series of studies have been performed on the effect of different tree species on deposition of fallout material and specific features of HMs accumulation in the forest litter of different biotopes in background and impact areas [7][8][9][10]. A high spatial variability of soil HM contents has been noted for forest BGCs [11][12][13], but factors responsible for meso-and microscale variation of HM in forest soils have not been studied sufficiently. ...
The influence of horizontal structure of spruce forest on the spatial distribution of acid-soluble Zn, Cd, Pb compounds and 137Cs in the litter and the humus horizon of soddy podzolic soil has been studied in the territory with the regional background level of industrial fallout. It has been found that the distribution pattern of Zn in the forest litter is a result of biogeochemical processes. The litter in fern–wood sorrel microplots contains increased amounts of Zn and Cd, while the contents of Pb and 137Cs are decreased. The distribution patterns of Pb and 137Cs in the litter are positively correlated with each other, since both elements are deposited from the atmosphere, and similar mechanisms account for their redistribution in the spruce forest ecosystem.
... Wielu badaczy, w tym Bergkvist [1] oraz Kónig [4], podaje, że cynk tworzy słabe połączenia ze związkami próchnicznymi (raczej wysokomolekulamymi), jednakże najczęściej, w warunkach kwaśnego odczynu, podlega nieselektywnemu sorbowaniu przez mineralne koloidy glebowe, z którymi łatwo przemieszcza się w głąb profilu. ...
Forms of Fe, Pb, Zn and Cu were determined by the means of seąuential extraction in podzol pro- files developed from granitogneiss in the Izerskie Mountains. Seven metal fractions were separated. Organie matter supply to soil profile was found to be a crucial factor determining the total concentration of lead in soil horizons. The main forms of copper and zinc were the ones occluded in Fe oxides and their total concentration inereased with the depth within the soils profiles, which proved the considerable mobility of these elements. The results obtained from the study show that the total amount of tracę elements in soil genetic horizons depends on the weathering process of primary and secondary soil minerals. organie matter input as well as the airborne contaminants. and their distribution in soil profile is modified by strongly acidic soil reaction.
... In forest litter and in the soil environment, heavy metals demonstrate diverse mobility (Czarnowska 1996). The mobility of Cu and Pb is strongly dependent on the solubility of organic matter (Bergvist et al. 1989). Lead is strongly bonded by organic matter of soil top layer and only slightly migrates into the depth of the profile, copper is a little more mobile, and zinc relatively easily moves into the depths of the soil. ...
Pollution of soils with heavy metals is particularly dangerous to living organisms. Invertebrates are sensitive to changes in soil conditions, and, therefore, may be considered invaluable indicators of soil disruptions. This study has been undertaken to determine heavy metal content in the in soil and extracted soil fauna in two types of forest habitats of Niepołomice Forest and to establish their impact on pedofauna– their density, diversity and trophic structure. The investigated sites varied in the soil or humus type, and the composition of forest stand and ground cover. The analysis of the pH value showed that the studied soils had acidic (pH 4.45-4.85). Small differences were observed in the content of heavy metals (lead, cadmium, nickiel, zinc and copper) in soil humid forest and fresh mixed forest. It results from the studies that the heavy metal content did not exceed the standards set out for the soils of Poland . The bioconcentration factor shows that both saprophytes and predatory invertebrates collected the largest amounts of zinc and smaller amounts of cadmium, and the remaining metals were collected in the following order: Cu> Ni> Pb. The results obtained show that the tested heavy metals could have an impact on the density and diversity of meso-and macrofauna. Probably soil fauna affected by other factors (soil moisture, organic matter content, type of humus) .
... The soil pH and its relationship with PTEs in soils have been noted by many authors, and it is generally agreed that pH is generally related to PTE mobility (Bergkvist et al., 1989;Violante et al., 2010), speciation (Drever, 1988), solubility and uptake by plants (Adriano, 1986;Breulmann et al., 2002). The solubility and mobility of PTEs increased with lowering the soil pH, but this change has been shown to decrease the organophyllic characteristics of some PTEs (Drever, 1988). ...
Conducting controlled burns in fire prone areas is an efficient and economic method for forest management, and provides relief from the incidence of high severity wild fires and the consequent damage to human property and ecosystems. However, similar to wild fires, controlled burns also affect many of the physical and biogeochemical properties of the forest soil and may facilitate remobilization of potentially toxic elements (PTEs) sequestered in vegetation and soil organic matter. The objective of the current study is to investigate the mobilization of PTEs, in Central Victorian forest soils in Australia after a controlled burn. Surface soil samples were collected two days before and after the controlled burn to determine the concentration of PTEs and to examine the physicochemical properties. Results show that As, Cd, Mn, Ni and Zn concentrations increased 1.1, 1.6, 1.7, 1.1 and 1.9 times respectively in the post-burn environment, whereas the concentrations of Hg, Cr and Pb decreased to 0.7, 0.9 and 0.9 times respectively, highlighting considerable PTE mobility during and after a controlled burn. Whilst these results do not identify very strong correlations between physicochemical properties of soil and PTEs in the pre- and post-burn environments, PTEs themselves demonstrated very strong and significant correlations. The mobilization of As, Hg and other toxic elements raise potential health concerns as the number of controlled burns are projected to increase in response to climate change. Due to this increased level of PTE release and remobilization, the use of any kinds of controlled burn must be carefully considered before being used as a forest management strategy in mining-affected landscapes which include areas with high PTE concentrations.
... Anthropogenic emissions of air pollutants and subsequent deposition of heavy metals are known to cause negative effects on chemical and biological processes in soils. Especially, in the northern hemisphere, large areas were polluted by various heavy metals via atmospheric deposition from industrial and traffic emission sources including power generation (Bergkvist et al., 1989;Steinnes and Friedland, 2006). Long-term acidification of terrestrial ecosystems caused a reduction of cation exchange capacity and increasing mobilization of heavy metals in soils with decreasing pH (Blake et al., 1999;McKenzie, 1980). ...
Rigorous studies on long-term changes of heavy metal distribution in forest soils since the implementation of emission controls are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area) and foliar chemistry from three decades ago. It was hypothesized that declining deposition of heavy metals is reflected in soil and foliar total contents of Pb, Cu, Zn, Ni, Mn and Fe. Mean soil contents of Pb in the stemflow area declined at the highest rate from 223 to 50 mg kg⁻¹ within the last three decades. Soil contents of Pb and Ni decreased significantly both in the stemflow area and the between trees area down to 80–90 cm soil depth from 1984 to 2012. Top soil (0–5 cm) accumulation and simultaneous loss in the lower soil over time for the plant micro nutrients Cu and Zn are suggested to be caused by plant uptake from deep horizons. Reduced soil leaching, due to a mean soil pH (H2O) increase from 4.3 to 4.9, and increased plant cycling are put forward to explain the significant increase of total Mn contents in the infiltration zone of beech stemflow. Top soil Pb contents in the stemflow area presently exceed the critical value at which toxicity symptoms may occur at numerous sites. Mean foliar contents of all six studied heavy metals decreased within the last three decades, but plant supply with the micro nutrients Cu, Zn, Mn and Fe is still in the optimum range for beech trees. It is concluded that heavy metal pollution is not critical for the studied beech stands any longer.
... DOC forms strong bonds and complexes with metal ions as they have numerous functional groups with negatively charged sites (Ephraim 1992;Tipping 1998;Tipping et al. 2011). Among the selected metals, mobility of Zn, Cd and Ni are greatly influenced by soil pH and are considerably mobilized when the soil pH is low, whereas, mobility of Cu and Pb are strongly dependent on the solubility of the organic matter (Bergvist et al. 1989). Metals may also be associated with carbonate, oxide and hydroxide minerals (Intawongse and Dean 2006) and play a significant role in the biological activity of organisms (Hernandez et al. 2003). ...
Forest fire is a natural disturbance that occurs in many terrestrial ecosystems specifically in the semi-arid environments and is considered to be an important cause of environmental change. Though many causes of fire are identified, including lightning, volcanic eruption, power line sparks, etc., human involvement is the most significant factor. Fire events are able to alter the physical, chemical and biogeochemical properties of the soil and surface materials and are able to release major and trace metals into the environment. This may be more significant in mining-affected and industrial landscapes, where elevated concentrations of metals present in the soil. After the fire event, metals become more mobile due to the increase in soil surface exposure and the mobility associated with ash dispersal. This mobility may increase the bioavailability of the metals, which may generate water quality issues and may contribute to human and environmental health concerns. Even though, the influences of fire on many soil properties are well established, the behaviour of metals with respect to fire is not well investigated. However, a few studies report that major and trace metals include Cd, Cr, Co, Cu, Hg, Mn, Ni, Pb, Zn and As are mobilized after fire with increased concentrations in soil and water resources and this might pose a risk to human health and ecosystems. Climate change may increase the intensity, frequency and areal extend of fire events and hence increase the metal concentrations and their potential health impacts. This paper reviews post-fire (wild fire) mobility of metals in soil common in contaminated forest ecosystems. The human and ecological health risks of these metals are also considered.
... The second correlation dependence is very important because Cr is usually considered (Bergkvist et al. 1989) in contrast to many other metals almost immobile in soil environment. The existing close correlation between magnetic susceptibility and Cr thus represents very good indicator of deposition load of soil which is not substantially influenced by secondary process in soils. ...
... Soluble zinc forms are easily taken in by plants from soil, the extent of which depends on a plant type and prevailing soil conditions (soil pH and composition) (Dudka and Chlopecka, 1990;Rudd et al., 1988). Zinc is one of the most mobile elements in soil (Bergkvist et al., 1989;Tyler and McBride, 1982). The factors that affect its increase are weathering of matrix, wet and dry atmospheric precipitation, decomposition of living matter and use of waste water in soil fertilization. ...
... Accumulation of heavy metals for prolonged period in organic parts of soils can contaminate soil organisms important for future soil development. Contents of cadmium up to (1 mgkg -1 Cd), lead (150 mgkg -1 Pb), zinc (100 mgkg -1 Zn) and copper (20 mgkg -1 Cu), according to (3), (4), (5) and (6) are still not sufficient to destroy soil organisms. However, 4-10 times of these concentrations can indirectly reduce the production of biomass, decomposition of litter and enzymatic activity in forest ecosystems in dependence of acidity, clay content and organic carbon of soils so that respective soil properties shouldbe taken into account in evaluation of toxicity of heavy metals. ...
Background and Purpose: The concentration of heavy metals in the environment has increased due to, among other masons, the influence of human activity. An increase in concentration is not at the same level for all metals and depends mainly on the amount and the way of transmission, as well as the source of pollution. The way that any heavy metal moves within an ecosystem depends on the biogeochemical cycle. There are a number of ways of circulation between the atmosphere, hydrosphere, geosphere and biosphere. Pie transmission of heavy metals can be observed through atmospheric flows in the form of gases as well as sedimentation of dry and wet deposits in the forest ecosystem Materials and Methods: The following heavy metals were monitored: lead (Pb) copper (Cu), zinc (Zn) and cadmium (Cd). Sampling was performed by means of funnels (throughfall) and the amount of precipitation was measured in rain gauges with a surface opening of 60 cm(2.) Rain gauges and funnels were placed diagonally by 6-9 items, each on 30x30m plot. On a control plot, where the impact of vegetation was excluded, funnels (bulks) were placed in a a random order or circularly. Plastic zero tension lysimeters were placed in the soil at the depth of 20 cm or beneath the humus layer and in mineral part of the soil at the depth of 100 cm. They collected the seeped liquid (seepage) in the soil. Sampling was carried out once a month. According to data obtained by monitoring, our forests and soils absorb more deposited heavy metals (wet and dry sedimentation) compared to the control samples in the open area. Results: Concentration of lead and cadmium in some samples in lysimeters at a depth of 10 cm was increased and according to drinking water standards in Croatia (Pb>2.0 mu gL(-1), Cd>0.20 mu gL(-1)) was t0o high. In lysimetric liquids, a slightly increased amount of heavy metals as observed. The average content of cadmium in lysimeters (spring, summer and autumn) was 0.13-0.36-0.37 mu g L-1, lead 4.3-4.2-5.1 mu g L-1, copper 3.3-5.3-4.6 mu gL-1, zinc12.7-8.9-17.6 mu gL-1, respectively. Conclusions: The forest ecosystems of Pedunculate oak and common hornbeam, With its biomass surface, allow increased dry deposition of substances which, by means of precipitation, become leached through tree-crowns. These results are in agreement with other investigations (Bretchel, 1989; Van Breemen at al. 1988; Lindberg at al. 1988;) which demonstrate that the deposition under forest tree-crowns is greater than in a open space, away from the influence of vegetation. This influences forest soils and soil solution in forest soils. Thew was an increased input of heavy metals into our forest ecosystem (it all monitored sites. At control locations (bulbs), where impact of vegetation is excluded, the amounts of heavy metals are always lower: On the basis of these investigations it can be concluded that problems of constant accumulation of heavy metals in soils are present in the region of lowland forests. In this process the types of soil play a significant role in buffering deposition substances which fall as precipitation.
... The supply of metals to plants depends upon the soil parent material and the weathering and leaching of the soil as well as on supply from precipitation (Bergkvist et al., 1989). Long-term changes in the elemental balance of soils and ecosystems are also related to concentrations in the atmospheric input and to the total cumulative deposition over long periods of time (e.g. ...
Geochemical and physiological indices gained at the background area and at the area under anthropogenic impact were compared. The study sites comprise 30 sample areas each. Overall, 600 samples of pine needles were designated for the delayed chlorophyll fluorescence measurement as well as 60 samples of soil and pine needle correspondingly were selected to perform the geochemical analysis. The biological uptake of the pine urban ecosystems is represented in the range: Mn (10,16) > P (7,19) > Ag (2,78) > Ba (2,76) > Cu (2,31) > Sr (1,85) > Ni (1,80) > Zn (1,75) > Pb (0,86) > Co (0,48) > Cr (0,40) > Zr (0,37) > V (0,36) > Ga (0,33) > Ti (0,21). In comparison with the background site data the biological uptake is increased in regard to V, Ti, Ni, Cu, Cr. The methodology implies the method of recording the relative index of delayed fluorescence with the help of fluorimeter “Photon 10”. The data accumulated in the course of the geochemical analysis allowed to distinguish common geochemical features of the study sites and revealed differences in soil and needle qualities. The value of relative index of delayed fluorescence (RIDF) under the impact of considerable anthropogenic impact is lower by 25% and more related to the background site. This deviation testifies that the human impact is present even on the early stage of ecosystem degradation.
This study assessed both the soil and litter copper (Cu) levels and their relationships with soil microbial activity, in fruit-tree production areas of central Chile where Cu-based pesticides are intensively sprayed. Samples of soil (0–20 cm depth) and litter from a number of selected orchards (kiwi, table grape, plum, and cherry) were collected and analysed for their Cu content and C-induced soil microbial activity. Results showed that the mean total soil Cu level was 225 mg/kg and soluble soil Cu was less than 0.01% of total soil Cu, as expected from pH values of study soils (range of 6.33 to 7.93). However, leaf litter Cu content was 3–7 times higher than in soil (mean of�681 mg/kg). Despite the soil and leaf litter Cu concentrations, no effect was observed on the C-induced soil microbial activity. We conclude that leaf litter exerts a protective role, preventing the entry of Cu into the soil and thus soil microbial toxicity.
L'évaluation des risques de sols pollués par les éléments traces métalliques (ETM) est délicate car l'activité anthropique interfère dans la nature et l'ampleur des apports d'ETM et peut pertur-ber la composition et l'organisation des sols. Après l'incorporation des ETM dans l'horizon de surface, la nature, l'usage et l'occupation des sols impriment des contraintes physicochimiques et biogéochimiques sur les phases porteuses d'ETM et les éléments libérés sont redistribués au sein de l'horizon de surface et/ou entre la surface et les horizons profonds. Dans les sols d'agro-et écosystèmes naturels, les redistributions sont étroitement liées aux processus pédologiques. Ce travail présente un retour d'expérience sur la variabilité des teneurs en ETM dans deux sites majeurs français, pollués par retombées atmosphériques d'origine industrielle ou par épandage d'eaux usées urbaines. La variabilité des teneurs en ETM y est analysée à différentes échelles : du secteur pollué, au parcellaire agricole, au solum, jusqu'aux constituants particulaires. Les exemples illustrent les nombreux facteurs qui déterminent in fine la teneur en ETM d'un échan-tillon de sol : l'ampleur de la pollution, le lieu et la profondeur des prélèvements, le temps de résidence des ETM, la nature du sol et les conditions physicochimiques, les propriétés intrin-sèques des ETM… L'emploi d'outils de la pédogenèse pour construire une stratégie d'échantil-lonnage adaptée au type de pollution et à l'échelle d'étude est un atout majeur dans l'étude des sols pollués. L'expertise en pédologie permet d'assurer la représentativité des échantillons et de garantir ainsi la pertinence d'études à des échelles fines, condition sine qua non pour juger valablement des dangers et risques. Comment citer cet article : van Oort F., Baize D. et Thiry M., 2022-Les sols pollués à l'épreuve de l'expertise pédologique : retour d'expérience sur la variabilité des teneurs en éléments traces métalliques des sols pollués et les stratégies d'échantillonnage dans deux sites majeurs français-Étude et Gestion des Sols, 29, 5-29 Comment télécharger cet article : https://www.afes.fr/publications/revue-etude-et-gestion-des-sols/volume-29/ Comment consulter/télécharger tous les articles de la revue EGS : https://www.afes.fr/publications/revue-etude-et-gestion-des-sols/ Les sols pollués à l'épreuve de l'expertise pédologique Retour d'expérience sur la variabilité des teneurs en éléments traces métalliques des sols pollués et les stratégies d'échantillonnage dans deux sites majeurs français
The aim of this study was to identify particulate matter (PM) sources and to evaluate their contributions to PM in the snowpack of three East Siberian cities. That was the first time when the PM accumulated in the snowpack during the winter was used as the object for source apportionment study in urban environment. The use of long-term integrated PM samples allowed to exclude the influence of short-term weather conditions and anthropogenic activities on PM chemistry. To ascertain the real number of PM sources and their contributions to air pollution the results of source apportionment using positive matrix factorization model (PMF) were for the first time compared to the results obtained using end-member mixing analysis (EMMA). It was found that Si, Fe and Ca were the tracers of aluminosilicates, non-exhaust traffic emissions and concrete deterioration respectively. Aluminum was found to be the tracer of both fossil fuel combustion and aluminum production. The results obtained using EMMA were in good agreement with those obtained using PMF. However, in some cases, the non-point sources identified using PMF were the combinations of two single non-point sources identified using EMMA, whereas the non-point sources identified using EMMA were split by PMF into two single non-point sources. The point sources were clearly identified using both techniques.
The distribution and cycling of nickel (Ni) in forests is greatly affected by their proximity to emission sources of the metal. The throughfall deposition is always richer in Ni than the bulk deposition. It can be inferred that some dry deposition enriches the throughfall. In remote forested areas, the hydrological fluxes of Ni do not differ a lot from those in litterfall. In addition, the current year needles in conifers have higher concentrations than the older needles, a sign of absorption and mobility of the metal. In contrast, near an industrial Ni source the older needles accumulate much more of the metal. The Ni content in bark tissue can be used to map the deposition distribution of the metal around an area (rural or urban). The concentrations of Ni in forest soils is also dependent on their distances from the Ni emission sources and the nature of the soil parent material. The Ni concentrations increase with soil depth due to the geogenic origin of the metal. Low pH greatly enhances the mobility of the metal in soils, much more than the leachability of organic matter.
The protection of wetlands is essential for sustainable development. The particular hydrology of wetlands creates conditions for the formation of hydric soils. Hydric soils are formed in oxide-reducing environments and perform important removal and re-oxidation of Fe and Mn oxides and hydroxides. They are also characterized by the formation of a superficial horizon enriched by the accumulation of organic matter. The objective of this study was to determine the concentration of essential (Co, Cu, Fe, Mn, Ni, Zn) and toxic (Al, Cd, Pb) elements in the soil solution in a wetland, surrounded by an intense agricultural activity area. The concentrations of the elements were evaluated according to the level of hydromorphy (border to the center) and the depth of the soil. The physical fractionation of these elements was also assessed (total and < 30 kDa), and the results were compared with the chemical speciation of these elements. Despite the high total concentrations of Al and Fe, the concentration of these elements was very low in the < 30 kDa fraction, which suggests that these elements are complexed with organic matter, in the form of hydroxides. Evidence of removal of Fe and Mn from the surface horizon was observed at the center of the wetland, where the highest level of hydromorphy is found. The results showed that the concentration of metals in the fraction < 30 kDa is insignificant, suggesting that the mechanisms of precipitation and/or adsorption to soil colloids play an important role in the regulation of this ecosystem.
Remnants of Semideciduous Atlantic Forest surrounded by numerous industries, intense road traffic and agricultural lands in Southeast Brazil have been affected by trace elements. We implemented a passive biomonitoring with the three most abundant native tree species (Astronium graveolens, Croton floribundus and Piptadenia gonoacantha) to answer these questions: 1) which species has the greatest potential to accumulate trace elements?; 2) does the leaf accumulation level of trace elements vary between the edge and interior of the forest remnants, between dry and wet periods or due to the distance from the industrial area?; 3) which species, among the most abundant in the forest remnants, would better indicate the spatial variations in trace elements pollution and which elements would be the most relevant for such spatial discrimination? Leaf samples were collected during the dry and wet seasons, at the edge and interior of four forest remnants. Trace elements were determined using inductively coupled plasma mass spectrometry (ICP MS). Few edge effects were evidenced in the leaf concentrations in all species. Higher concentrations of most trace elements were measured during dry season. Although C. floribundus showed the most accumulating capacity, A. graveolens was the most appropriate species to discriminate spatial variations. The forest closer to the industrial area was distinguished from the others by Mn and Ni from oil burning, but the metal pollution from the industrial area did not interfere on the leaf concentrations in A. graveolens sampled in the urban and rural forests.
Przeanalizowano całkowitą zawartość oraz formy pierwiastków śladowych w glebach leśnych wytworzonych z krystalicznych skał krzemianowych w Górach Izerskich na obszarze degradacji drzewostanów. Stwierdzono wyraźnie podwyższoną zawartość ołowiu, szczególnie w próchnicy nadkładowej. Cynk, miedź i nikiel występują w relatywnie małych ilościach. Analiza form pierwiastków śladowych wskazuje na dużą ich ruchliwość w profilu glebowym. Stwierdzono, że na całkowitą zawartość tych pierwiastków w poszczególnych poziomach genetycznych decydują: dopływ substancji organicznej oraz zanieczyszczeń, silnie kwaśny odczyn oraz zawartość w skale macierzystej. Wydaje się, że stwierdzone koncentracje pierwiastków śladowych nie stanowią zagrożenia dla środowiska przyrodniczego Gór Izerskich.
Changes in the amount and chemical composition of forest floor between the year 1982 and 1998 in spruce forest were studied. The forest stand was located at the altitude 1200-1450 m on Cambic Podzol of granodiorite slope deposits.
The amount of forest floor has increased. Thha stands have still been in the stage of accumulation of organic matter on the soil surface. The content of elements, except for lead, was within natural limits. The contents of lead were significantly higher than background natural contents due to air pollution load. However, the concentration in L horizon decreased between 1982 and 1998 as a result of air pollution load decrease.
In the area of Katowice city (S Poland) a significant increase in the number of sites of some epiphytes (mainly from the genera Orthotrichum and Ulota) were recorded. The comparison of their distribution in 2001 and 2015 shows two groups: (1) species of which the number of localities is obviously higher, e.g. Orthotrichum diaphanum, O. obtusifolium, O. pumilum and O. speciosum and (2) species new in the bryoflora, i.e. Leskea polycarpa, Orthotrichum affine, O. patens, O. rogeri, O. stramineum, O. striatum, Radula complanata, Syntrichia latifolia, Ulota bruchii and U. crispa. The analysis of the preference of epiphytes towards inhabited phorophytes reveals that the most commonly and abundantly inhabited species were poplar and willow trees, which show higher pH values of bark.
Residue biomass from conventional forestry, such as slash (i.e., tree tops and branches) and stumps, are used at an increasing rate for energy purposes in Sweden. This review examined current knowledge on how extraction of forest biomass for large-scale energy production, including the practice of ash application for nutrient recycling, influences the mobility and stocks of trace metals in the forest environment at different time scales. The study focussed on Swedish energy production systems and contemporary forest management practices, as well as the heavy metals lead (Pb), cadmium (Cd) and mercury (Hg). The historic accumulation of these elements in forest soils has mainly originated from diffuse, long-term atmospheric deposition.
There is little conclusive evidence that slash harvest generally increases the risk for mobilization of trace metals from soils during the regeneration phase, compared with stem-only harvesting. However, microbial transformation of mercury into the highly toxic methyl mercury (MeHg) species is facilitated in suboxic soil conditions that may increase during the regeneration phase. Therefore it has been hypothesized that stump harvest could result in increased mercury methylation and transport to surface waters, owing to stump harvest effects on soil physical conditions and hydrological pathways. The few studies available on the stump harvest effects of Hg showed no consistent difference in runoff from clear-felled and stump harvested catchments compared to clear-felled and soil-scarified catchments in terms of concentrations or fluxes of MeHg.
Assuming that the highest trace metal concentrations in wood ash recommended by the Swedish Forest Authority are not exceeded, wood ash application does not currently increase metal loads at the national scale, because trace metal export in harvested biomass is much larger than that returned in wood ash. The net load of Pb, Cd, and Cu will not increase at the local scale if ash doses do not greatly exceed the compensation for nutrients exported in harvested biomass. Biomass harvest and ash application have negligible effects on the load of mercury to forest soils.
A large number of studies have examined the effects of wood ash on trace metal content in soil, water and biota. Most studies showed no effect of wood ash application. When increased concentrations were found (Cd, Cr, Cu, Zn), this was in soils where concentrations remained well below harmful levels. Relatively fewer reports of increased concentrations are reported for soil water and plants, and no effects were reported for edible berries or fungi.
In der Ökologie sind Veränderung und Stabilität zeitbezogene Begriffe. Jedes Ökosystem ist von Natur aus in ständiger Veränderung und doch, aus dem zeitlichen Blickwinkel des Menschen betrachtet, ein Garant für Stabilität. In einer langen Sukzessionsfolge entwickeln sich die Ökosysteme von einfachen Pionier- zu intensiv verflochtenen Artengesellschaften (Abb. 2.1). Allerdings hat die Natur einige hundert bis tausend Jahre dafür vorgesehen.
In the preceding chapters various aspects of biogeodynamics of pollutants in soils and sediments have been described. Due to continuing immissions from anthropogenic activities different contaminants have accumulated in soils and sediments and become bound to the soil. Changes in environmental conditions may change the binding capacities of soils, resulting in a non-linear, possibly massive, release of these contaminants again leading to polluting loads.
The mobility of Cd, Cu, Pb and Zn in metalliferous mine tailings and adjacent soils at two historic mine sites in the UK were monitored over a period of one year. The heaps of tailings were found to contain distinct layers with anomalous metal concentrations which were higher than the average composition of the bulk tailings by factors of 53 for Cd, 49 for Cu, 6 for Pb and 30 for Zn. In the surrounding acid slope soils, the relative retention of Pb was up to 99 times greater than that for Cd. The relative flux of metals in local soils was found to follow the order Cd > Zn > Cu > Pb which is strongly related to the electronegativities of these elements.
This chapter presents the environmental fate modeling approach for the terrestrial environment. The chapter discusses the modeling of concentrations in terrestrial compartments distinguished by land uses and/or covers (such as agricultural soils) and modeling of contaminants in (terrestrial) plants. Pure environmental fate models describe the relationship between emissions and concentrations trying to quantitatively answer the question of “how much of a substance ends up where.” Thus, model development and set-up may require different subdivisions of the zones in terms of compartments distinguished and parameterization of these compartments if one has to develop a pure environmental fate model or an exposure model. The chapter discusses the various compartments distinguished in the terrestrial environment. When assessing indirect human exposures, plants need to be considered because they form the basis of most of the food chains or webs because of their role as primary producers. Reasons for distinguishing between several plant compartments either as different plant parts or as different plant species include: different plant parts are exposed because of different processes (especially foliar vs. root uptake, but also attachment of (particle-bound or gaseous) substances to plant aboveground surfaces), consumption occurs only of selected plant components (e.g., root, leafy, stem and corn produces) and different plant parts or species are affected to different degrees by processes such as harvesting, litter fall and growth.
Lead concentrations, fluxes, and storage were measured in the vegetation, forest floor, and acid, sandy mineral soil (Quartzip-samments) of a forested watershed in the New Jersey Pine Barrens. Atmospherically deposited Pb at the McDonalds Branch Watershed was 140 g haâ»Â¹ yrâ»Â¹ (8 ..mu..g Lâ»Â¹ in bulk precipitation) in 1980 to 1982, a substantial reduction from 350 g haâ»Â¹ yrâ»Â¹ (17 ..mu..g Lâ»Â¹ in bulk precipitation) in 1978 to 1979. Virtually all Pb falling on the uplands was retained - 75% by the organic forest floor and 25% by mineral soils, especially in B and C soil horizons. Total Pb content of the forest floor was 7.6 kg haâ»Â¹, with an accumulation rate of 100 g haâ»Â¹ yrâ»Â¹ (1980-1982), or 1.3% of the forest floor pool. Estimated mean residence time of Pb in the forest floor was 220 yr. About 35 g Pb haâ»Â¹ yrâ»Â¹ moved out of the forest floor in solution through the E horizon and was correlated strongly with dissolved organic matter. Approximately 30 g Pb haâ»Â¹ yrâ»Â¹ accumulated in the B and C soil horizons. Less than 1 g Pb haâ»Â¹ yrâ»Â¹ percolated past a depth of 2 m. Lowland muck soils and vegetation accumulated 98% of incoming Pb, with only 3.2 g Pb haâ»Â¹ yrâ»Â¹ exported in the stream. Lead concentrations in the stream were correlated positively with dissolved organic matter and water level in the swamps. Lead in biota was contained mainly in the bark, fine roots, and foliage. Concentrations were: fine roots (18 mg kgâ»Â¹) > bark (15 mg kgâ»Â¹) > foliage (4 mg kgâ»Â¹) > wood (0.5 mg kgâ»Â¹). Although Pb concentrations in herbs, mosses, and lichens ranged from 10 to 60 mg kgâ»Â¹, these plants accounted for very little biomass. Total Pb content of biota was 335 g haâ»Â¹, about 4% of the forest floor Pb content.
Mitt. Dtsch. Bodenkdl. Ges., 25, S. 143-148, (1977).
This report deals with the turnover of Mn, Co, Ni, Cu, Cd, and Pb and is derived from extensive investigations of the element budget of 2 forested ecosystems. A spruce ecosystem in the Black Forest (Brown Earth on granite-porphyrite) is compared with a pine ecosystem in the southern upper Rhine plain near Hartheim (Pararendzina on calcareous and stony Rhine sediment). The comparison is based on average elemental concentrations and fluxes in incident precipitation and soil solution (depth of 3 dm). Dry deposition is not taken into account. The average heavy metal concentrations in incident precipitation were - except for Ni - higher in the industrialized Rhine plain than in the Black Forest. In contrast, the Brown Earth with the exception of Cu has higher values in soil solution. The relatively high Cu concentrations in soil solution in the Pararendzina show that the formation of poorly soluble Cu precipitates occurs to a limited extent only. The general level of heavy metal concentrations in soil solution is controlled not by interactions between the solid and liquid phases but rather by the concentrations in incident precipitation or throughfall. This is not true for Mn in the moist and acid Brown Earth, where this element is subject to intensive mobilization from the soil. In both ecosystems, elemental fluxes are determined primarily through water amounts. Thus in spite of the lower concentrations at the Black Forest site, the input is greater in the Rhine plain. The heavy metal flux balances are all positive for the pine ecosystem. In the spruce ecosystem only Ni, Cu, Cd, and Pb show clearly positive balances. Mn has a negative balance, with the output exeeding the input substantially.
Total wet and dry deposition of main and trace elements is calculated from the flux balance for precipitation fluxes of forest canopies for which precipitation fluxes above and below canopy as well as the flux coupled with litterfall has been measured. Retention and leaching of substances are estimated for groups of elements individually showing similar chemical and physiological behavior. It is shown that dry deposition may be very important and may even exceed wet deposition to forests in rural areas. Dry deposition rate in the same area depends clearly upon forest type, i. e. upon the surface quality. Ecological consequences of atmospheric deposition to forests are discussed.
A controlled use of a cation exchanger is proposed as a method for speciation of Cd**2** plus and Zn**2** plus and to determine low concentrations of these two elements in water. At ionic strength below 0. 01, concentrations of Cd and Zn of less than 0. 1 ppb and 3 ppb, respectively, can be analyzed quantitatively. The ion exchange method was tested on two natural humus-rich surface waters adjusted to various pH in the interval 3-8. At pH below 4. 5 almost all cadmium was free. At pH around 6. 5 about 50 percent and at pH around 8 about 10 percent was free. The two waters, a bog water and a river water, similar in Fe and TOC content, differed in cadmium complexing strength at neutral pH, the bog water showing 50 percent higher strength. For zinc the tendency was the same but the binding was slightly stronger resulting in 50 percent binding at pH 6.
A research programme on air pollution effects in Fagus sylvatica forest ecosystems of the Vienna woods was set up, after a severe die-back had cleared large patches of forest floor vegetation in the infiltration zone of stemflow water after the winter of 1978/79. Since then vegetation has partly recovered. -from English summary
In the catchment ‘Grosse Ohe’ in the National Park ‘Bayerischer Wald’(ϕ = 48°57′ N;λ = 13°26′E) quantitative forest hydrological studies are carried out since 1978. Since 1981 the pH-values of the precipitation in the open are measured, since 1983 also the bulk deposition at four sites in the open and two plots under spruce in different altitudes.
Upto now the results show that the spatial distribution of the bulk deposition in the open, independent of the temporal variation of the element concentrations, are caused by the distribution of precipitation in the catchment. Passing the canopy the precipitation is enriched by adsorption of gaseous deposition, filtering and leaching of air pollutions and nutrients. Exceptional high enrichments can be expected if the spruces are in fog or in drifting clouds filtering droplets. This process happens in about 50% of all sampling periods in the higher altitudes of the catchment.
The present situation is reported for open field precipitation input of 4 anions and 13 cations sampled during a state-wide pilot study covering three time periods totaling four months. Furthermore, results of comparisons between open area and adjoining spruce stands are presented. The annual average concentration and deposition rate for 1982 and 1983 are shown for 3 different locations in the Reinhardswald Research Area as well as for the time period October 1983 — September 1984 at several locations in the Research Areas Konigstein, Grebenau and Witzenhausen.
Far-reaching acidification of forest soils has occurred in southern Sweden during the last decades. The decreasing pH has, directly or indirectly, increased the solubility of several elements in the soil, including magnesium, aluminum, cadmium and zinc. This has resulted in high concentrations of these elements in the soil-water and a considerably greater output than input from the forest ecosystems. Both deciduous and coniferous forest soils have become acidified but the solubilization and flow of metals is greater in spruce stands than in beech and birch stands on originally similar soil.
Trace constituents are removed from the atmosphere either by incorporation into rain or by deposition onto surfaces like soil, vegetation, waters. Dry deposition onto natural surfaces can hardly be represented by mathematical models or by artificial surfaces, for realistic approximations of the complex boundary (e.g. vegetation/ atmosphere) is not yet possible. Therefore, it was attempted to determine the deposition of atmospheric trace constituents to a natural surface in a direct way. A beech- und a spruce forest were used as a natural surface. The amount of matter dry deposited on the vegetation surface is derived by means of the difference of concentrations in precipitation above and beneath the canopy area. Leaching and absorption of certain substances by leaves and twigs are taken into consideration. Dry deposition velocities are determined from the transfer rates (atmosphere to vegetation) of the aerosol compounds and their simultaneously measured air concentration. They will be discussed with results of other investigations.
This chapter discusses a number of factors influencing the throughfall and stemflow quality and their variation. The effect of the canopy in altering the precipitation quality is also discussed. The annual nutrient return to the forest soil for the elements K, Na, and S is predominantly via throughfall and stemflow and little because of litterfall. Stemflow transfers only 5–20% of the total in precipitation-borne solutes, yet it is the major nutrient input to restricted areas of the forest floor. Because throughfall and stemflow are associated with precipitation events, the transport of nutrients contained in throughfall and stemflow depends on the magnitude, timing, and form of the precipitation. Thus, a reliable estimate of throughfall nutrient flux demands a good forest hydrological budget. The quantity and distribution of throughfall and stemflow depends on microscale features of canopy structure, such as crown density, closeness of the foliar elements, distance from the nearest bole, or open spaces in the canopy.
The solubility behaviour of heavy metals determines mobility, leaching, availability, and toxicity of these elements in soils. In model experiments the solubility of Cu, Zn, Cd and Pb was investigated in equilibrium solutions of different soil samples under varying conditions. The solution concentrations of heavy metals increase in the order Cd> Zn>>Cu> Pb with increasing total content of these elements and decreasing pH. The concentrations of Cd and Zn may already raise at pH values below 6, whereas those of Cu and Pb increase below pH 4 to 5. At acid soil reaction the metal concentrations are reduced in subsoil samples with low content of organic matter by increasing clay content and CEC. In surface soils humic substances depress solution concentrations of heavy metals at strongly acid conditions more effectively than mineral soil components. The metals are immobilized by soil organic matter in the order Cu>Cd>Zn> Pb. At weakly acid to alkaline soil reaction these elements are mobilized in the same order by soluble organic substances. Especially additions of decomposable plant material to soils lead to a mobilization of heavy metals. Pb is least affected by these processes because of a strong fixation by mineral soil components.
At least three groups of compounds were found to complex Zn ²⁺ and Cu ²⁺ in soil solution from the A horizon of a Williamson silt loam. A nondialyzable fraction of soil solution ligands had a poorly defined acid dissociation, pKa, ranging from 3 to 4.7. The dialyzable fraction had acid dissociation constants of 4.5 and 9.5, which were attributed to aliphatic and amino acids, respectively. The equivalent concentration of the nondialyzable acid fraction was only 1/40 that of the dialyzable fraction, but was more effective in complexing Zn and Cu in the soil solution. The average metal/ligand ratio was equal to unity in complexes of both the dialyzable and nondialyzable fractions with Zn ²⁺ and Cu ²⁺ . Estimated, log 10 (average formation constants) of the nondialyzable‐metal complexes were calculated on the basis of titratable acidity as 4.3 ± 0.1 and 5.5 ± 0.1 for Zn ²⁺ and Cu ²⁺ , respectively.
The quantitative distribution and the chemical composition of the rainfall in a 100-years old beech forest and a neighbouring 55-years old planted spruce forest are reported. Average annual values of throughfall, stem flow and interception are estimated as 70%, 11% and 19% for the beech forest and 58%, 3% and 39% for the spruce forest of the incident rainfall in an open field. The soil of the spruce forest is about 19% drier than that of the beech forest, because of high interception and long transpiration period of the former forest. The following chemical features are discussed: pH, conductivity, amounts of Na, K, Ca, Mg, Mn, Cl, SO<sub>4</sub>- S, PO<sub>4</sub>- P and tot.-N. Extrapolated annual values of nutrients in the throughfall + stem flow amount to 107 kg/ha and 215 kg/ha in the beech and the spruce forests respectively. A high percentage of the nutrients must derive from dry deposited aerosols and this was particularly so for Na, Mg, Cl and Ca. There was no indication of the spruce forest to adhere more aerosols than the beech forest, and the higher amounts of nutrients in the rainfall of the spruce forest probably derived from stronger leaching processes of the canopy. /// Овсуждается количественное распределение и химияеский состав осадков в 100-летнем буковом лесу и соседствующем с ним 55-летним саженом еловом лесу. Средне-годовое соотношение количества осадков, проходящих под полог древостоя, стока по стволам и осадков, задержанных кронами древостор, составляет вбыковом лесу 70: II: 19%, a в еловом - 58: 3: 99%, по сравнению с количеством осадков на открытом открытом поле. Почва в еловом лесу примерно на 19% суше, чем в буковом, вследствие того, чго там большое количество осадков задерживается растениями и более длительный испарения. Овсуждаются следующие химические показатели: pH, проводимость чодержание Na, K, Ca, Mg, Mn, Cl, SO<sub>4</sub>- S, PO<sub>4</sub>- P и общего азота. Экстраполированные данные годового количества эток по стволам составляют 107кг/га в буковом и 215кг/га в еловом лесу. Большое количество питательных веществ должно высвобождатьчя из сухих осаждающихся аэрозолей, это относитчя в частности к Na, Mg, Cl и Ca. Данных о том что в еловом лесу аэрозолей больше, чем в буковом, нет, и большее количество пительных элементов в осадках елового ле са возможно объяснить более интенсивными поцессами выщелачивани я лесной подстилки.
Comparisons were made on the decomposition rates of different fractions of spruce needle litter from numerous sites around two metal processing industries in central and southeastern Sweden, emitting Cu, Zn, Cd and Ni, and Pb, Ni and Cd, respectively. All measurements were performed under controlled laboratory conditions. At water capacity and 15°C a CO<sub>2</sub> evolution rate in partly disintegrated litter of ca 0.23 mg C/g dry matter, 24 hr was measured in samples with > 10 μmol Zn + Cu + Cd + Ni per g, compared with ca 0.50 mg C in samples with < 5 μmol/g. Highly significant negative correlations were obtained in all materials between heavy metal concentration and CO<sub>2</sub> evolution rate or dehydrogenase activity. It is concluded that, in acid forest sites, the general decomposition rate will be depressed even by moderate concentrations of heavy metal ions, at least during those parts of the year when the water supply is adequate. /// Сообщается об изучении скорости разложения различных фракций хвойной еловой подстилки из многочисленных местообитаний около двух металлургических заводов в центральной юго-восточной Швеции, дающих в качестве отходов соответственно Cu, Zn, Cd, Ni, а также Pb, Ni, Cd. Все измерения проводились в лабораторных контролируемых условиях. При достаточной влажности и 15°C измеряли выделение CO<sub>2</sub> из слегка разрыхленной подстилки, в течение суток в пробах, содержащих 0,23 мг С/г сух. веса с ∼ 10 μмоп Zn + Cu + Cd + Ni/г и в пробах, содержащих 0,50 мг С/г с ∼ 5 μмол/г. Получены четкие отрицательные корреляции между увеличением концентрации металлов и выделением CO<sub>2</sub> или активностью дегидрогеназы. Сделано заключение, что в местообитаниях с кислой реакцией общая скорость разложения подавляется больше, чем при более умеренных концентрациях ионов тяжелых металлов, по крайней мере в течение сезонов с достаточной влажностью.
Field studies were conducted to examine the processes and environmental factors which influence or control ion transport in ecosystems receiving chronic acid precipitation. Specifically, these studies focused on changes in solution chemistry during rainfall percolation through a cool, moist balsam fir forest in the subalpine zone of the White Mountains of New Hampshire. Patterns of solution chemistry exhibit the following distinctive trends: (1) atmospheric sulfate is the dominant anion in the leachate from this system, although organic ligands were probably the major anionic species in solution in the past; (2) soil aluminum leaching appears to be increasing in response to acid precipitation, resulting in comparatively high dissolved aluminum concentrations in the soil solution; and (3) most neutralization of atmospheric sulfuric acid occurs at depth in the mineral soil, rather than in the fir forest canopy or forest floor. The behavior of individual ions in the fir zone system appears to depend upon the differential effects of the following major factors: atmospheric input rates, biological demand, ion exchange affinities, acidity of the percolate, and rates of ion release and consumption in weathering, mineralization, and geochemical buffering reactions. /// Процессы и внешние факторы, влияющие на транспорт ионов или регулирующие его в зкосистемах с хроническими кислыми осадками исследованы в полевых условиях. В частности, эти исследования сфокусированы на изменениях химизма растворов в лериод просачивания осадков в холодном влажном лесу бальзамической пихть в субальлийской зоне Бельх Гоп в Нью Хэмпшире, США. Особенности химизма растворох вскрывают следующие олределенные тенденции: 1. агмосферные сульфаты - доминирующий анион, выщелачивающийся из этой системы, хотя органические лиганды - очевидно осноыной вид анионов в растворе в прощлом; 2. выщелачивание почвенного алюминия очевидно возрастает в результате закисления осадков, что приводит к повышению концентрации растворенного алюминия в почвенном растворе и 3. в основном нейтрализация атмосферной серной кислоть имеет место в минеральном горизонте почвы в сравнении с кронами пихтового леса или подстилкой. Поведение отдельных ионов в системе пихтовой зоны зависит от различных сочетаний следующих факторов: скорость загрязнения атмосферы, биологических потребностей, обменной емкости ионов, кислотности перколята, скорости высвобождения ионов и поглощения в процессах выветривания, минерализации и геохимического забуферивания.
The concentrations of twelve metal elements (Na, K, Rb, Mg, Ca, Al, Fe, Mn, Cu, Zn, Cd, and Pb) in roots, rhizomes and shoots of the wood anemone Anemone nemorosa L. from 50 woodland sites in southern Sweden were related to various soil properties incl. extractable concentrations in the soil, using a stepwise regression programme. As a mean of the three materials > 50% of the variability in the biomass concentrations of most of the metals were accounted for (in Ca 76%, in Mn 68%). Extractable amount in the soil offered the best prediction of plant concentration in most elements, when only one variable was considered, but inclusion of some function of the acid-base conditions of the site usually improved the prediction considerably. In Al, Fe, and Rb the clay content was more closely related than extractable amount to plant concentration. Organic matter content was only related to the Cu concentration of the roots. A very close relationship was measured between the Rb:K ratios of the three plant components. No relationship between the exchangeable Rb:K ratio of the soil and the Rb:K ratios of the plant was found. /// Концентрация 12 металлов (Na, K, Rb, Mg, Ca, Al, Fe, Mn, Cu, Zn, Cd, Pb) в корнях, ризомах и проростках Anemone nemorosa L. из 50 лесных местообитаний в южной Швеции зависила от различных свойств почвы, в том числе концентрации экстрагируемых фракций в почве при обработке данных методом степенной регрессии. При средних из 3-х видов материала более 50% от колебаний биомассы рассчитаны концентрации большинства металлов (в Ca 76%, в Mn 68%). Экстрагируемое количество в почве оказывается лучшим показателем концентрации в растениях у большинства металлв, если рассматривать лишь одну валиабельность, но включение некоторых других функций, зависящих от условий щелочности-кислотности в местообитании значительно уточняет показатели. Для Al, Fe и Rb содержание глинистых частиц более четко коррелирует с содержанием в растении, чем количество экстрагируемых вешеств. Содержание органического вещества коррелирует лишь с концентрцией в корнях. Очень четкя корреляция найдена в отношении Rb:К у 3 растительиых компонентов. Отсутствует взаимосвязь между отношением экстрагируемых Rb:К в почве и Rb:К в растении.
(1) Multiple regression analysis was applied to single-event samples of throughfall beneath oak trees to separate the contributions of dry deposition and canopy exchange to the net deposition (throughfall minus precipitation). (2) Results for chestnut oak (Quercus prinus L.) in the growing season indicate that 62 and 42% of the net deposition of SO2- 4 and Ca2+, respectively, were supplied by canopy exchange, with the remainder being washed-off dry deposition. For white oak (Quercus alba L.), the corresponding values were 81 and 73%. (3) Dry deposition accounted for 30 and 71% of the total atmospheric input of SO2- 4 and Ca2+, respectively. (4) For nitrate, dry deposition was at least 30% of the total atmospheric input, but some uptake of both wet and dry deposition probably occurred in the canopy. (5) For potassium, much of the measured dry deposition appeared to be particulate material released and redeposited within the canopy. (6) Wet deposition dominated the throughfall flux of sulphate and nitrate, but dry deposition dominated that for Ca2+ and canopy exchange dominated that for K+.
Soil conditions were investigated in South Swedish localities where beech forest and first generation planted spruce exist side by side. The main study area was at Kongalund; further observations were made at Slätteröd, Bökeberg and 20 more localities. When beech is replaced by spruce, the physical properties of the upper soil horizon change, there is an accumulation of organic matter and mor forms at the soil surface. The amount of available water decreases and less rainwater supplements the underground water. There is less exchangeable K and Ca in the upper horizon of spruce forest soil, but more Fe, PO<sub>4</sub> and acid substances resulting in a decrease in pH to a depth of 50 cm or more. Less nitrification and a greater mobilization of mineralized NH<sub>4</sub> occurs in spruce than in beech forest soil. It is concluded that soils of moderately good mineral composition uninfluenced by underground water suffer most damage from podsolization when planted with spruce. /// Проводились исследования свойств почвы в расположенных по соседству буковом лесу и участке саженных елей генерации. Наиболее детальное исследование проведено на специальной пробной плошадке в Конгалунде и менее детаьное - на двух одинарных участаках и 20 двойных участках. Установлены следующие основые изменеия: Аккумуляция органического вещества и формирование мора на поверхности почвы в еловом лесу. Измения некотоых физических свойств верхнего горизонта почвы. Снижение количества доступной воды в еловом лесу и уменьшение транспорта осадков к гпунтовым водам. Уменьшение содержания обменного К и Са, но увеличение Fe, PO<sub>4</sub> и кислот в верхнем горнзонте почвы под еловым лесом. рН снижается на глубине 50 см по крайней мере. Процессы нитрификации затормаживаются, и минерализованный NH<sub>4</sub> в почвах под еловым лесом мобилизуется более интенсивно. Эти различия обсуждаются с эколого-почвоведческой точки зрения, сделано заключение, что почвы с достаточно хорошим минеральным составом и без влияния грунтовых вод должны более сильно страдать от процессов оподзоливания под еловыми насаждениями.
Metal speciation of Al, Cd, Cu, and Pb was studied in soil solutions containing humic substances (HS). The ion exchange column procedure was optimized and compared with a modification of the equilibrium dialysis (ED). A soil solution, for which the metal speciation at equilibrium could be calculated, was obtained from the ED. The solution was processed through columns with pH-adjusted (pHeffluent = pHinfluent) and Na+ saturated strong cation exchange resins.Using a pH-adjusted exchanger, there was only a slight dissociation of Al-humic complexes (AIHS) in the column (x = 7%). The dissociation was independent of pH (4.0–5.5) and v Al (μmol Al bound/g HS) in the range 51–500.The kinetic lability of CdHS, CuHS, and PbHS in the pH-adjusted exchanger (Cd>Pb>Cu) was greater than for AlHS. Among the heavy metals, the ion exchange column procedure was most suitable for fractionating Cu into humic and non-humic forms. The CuHS concentration obtained with the Na+ exchanger was 90–109% of the one obtained with ED, the variability being independent of v Cu (μmol Cu bound/g HS), though slightly dependent of sample pH.
Submicron aerosol deposition to outdoor vegetation was evaluated by measuring vegetation and air concentrations of 212Pb, 214Pb, and 7Be attached to atmospheric aerosols. A biomass-normalized deposition velocity (VD), with units of m3 kg−1 s−1, was used to compare species and isotopes with respect to air-to-vegetation transfer rates. For 212Pb (), higher night-time air concebtrations dominate deposition, while for 214Pb (), deposition measurements over shorter time periods relative to changing atmospheric conditions were possible. Calculated VD values were usually higher for 214Pb, possibly reflecting wind-enhanced deposition during the afternoon period of sampling. Evergreen species, including pines, were not appreciably different from deciduous species. Most striking was the narrow range of results (factor of 6 for 34 212Pb measurements of 20 species). Beryllium-7 () was used to evaluate time-integrated deposition by sampling vegetation in California near the end of dry summers. Similar deposition rates were found for this isotope. The results of the study indicated that naturally radioactive atmospheric aerosols can be used to understand the dynamics of submicron aerosol deposition to ecosystems.
Procedures were developed for the partition of heavy metals (Cu, Co, and Zn) between complexed and uncomplexed forms in soil solution. Competition for the above cations by complexing agents naturally present in soil solution and added complexing agents that form metal complexes soluble in organic solvents was determined by measuring the distribution of metal between aqueous and organic phases in a two‐phase system. The degree to which the metal was complexed in the original soil solution could be deduced by comparing the amount of metal extracted from soil solution with that extracted from water at the same pH. Examination of soil solutions from several mineral soils indicated that in the case of Cu as much as 99% of the metal may exist in a complexed form.
It was discovered that organic matter reacted with divalent metal ions in a manner similar to chelation reactions. Radioactive zinc was used to facilitate the adsorption measurements. Multiple regression was used to develop a prediction equation to determine the amount of zinc adsorbed as influenced by zinc added, pH, and ionic strength of the solution.
Removal of organic matter by oxidation with hydrogen peroxide destroyed the ability of the soil to chelate zinc. Removal of hydrous silicates did not influence the retention of zinc by the soil.
The organic matter was fractionated into the humic and fulvic fractions. Both fractions reacted with zinc in a manner similar to the untreated soil. Methylation of the organic matter was used to determine the functional groups involved in the chelation reaction. Carboxyl groups did not appear to be important.
The stability constant for the zinc soil complex was investigated by two independent methods. For a Maumee sandy loam soil at pH 7 and 2 N KCl it was found to be 5.6.
The average annual Pb input to the northern hardwood forest at the Hubbard Brook Experimental Forest in central New Hampshire was 266 g ha⁻¹ year⁻¹ based on 4 years of records. Lead output via streamwater and eroded particulate matter was 5.0 and 1.1 g ha⁻¹ year⁻¹, respectively. Lead concentration in precipitation averaged 22 µg liter⁻¹ and showed a significant decline over the 4 sample years (1975–1978).
Lead input to the ecosystem via meteorological vectors is accumulated in the forest floor. Total current Pb content of the forest floor was 8.6 kg ha⁻¹ and showed no significant differences along the elevation gradient of the watershed (400–800 m). Lead concentration in the forest floor was maximum on the ridge due to a minimum forest floor mass relative to the rest of the watershed. Within the forest floor, maximum Pb concentration is in the fermented (F) layer.
Total Pb content of the forest biomass (stems ≥ 10 cm dbh) was 1,248 g ha⁻¹. Lead concentration in the biota was in the following order: lichens (213 µg g⁻¹) > mosses (190 µg g⁻¹) > tree twigs (26 µg g⁻¹) > roots (20 µg g⁻¹) > bark (19 µg g⁻¹) > leaves (7 µg g⁻¹) = bracket fungi (7 µg g⁻¹) > wood (0.7 µg g⁻¹).
Disturbance of the forest ecosystem through harvest cutting, other than through increased runoff, increased erosion, and transport of particulate matter, does not alter the biogeochemistry of Pb and does not result in increased mobility and export of Pb due to gross or subtle alterations of the behavior of Pb in the ecosystem.
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Concentrations and annual fluxes of K, Na, Ca, Mg, Al, Fe, Mn, Zn, N, S, P, Cr, Cu, Ni, Pb, Sb, Bi, Cd, Hg, and Tl were measured in the precipitation input to the forest canopy, in precipitation beneath canopy, and in the seepage water below the humus layer and below the tree root zone (output) both in a Central European beech ( Fagus silvatica ) and in a spruce ( Picea abies ) forest. Concentrations were determined in an acid loess loam soil from the beech site and in a calcareous little‐weathered loess C‐horizon for the same elements plus Sr and V.
When precipitation was passing through the forest canopy, some elements were partially retained (P, Cu, Fe, Zn, Hg, Cr). The flux of other elements increased during canopy passage.
Strong retention of Pb and Ni in the organic surface layer (O‐horizon) was found when seepage water passed through it. Within the mineral soil, retention of dissolved elements from the seepage water is observed in the case of K, Ca, Fe, N, S, P, Cr, Pb, Sb, Hg, and Tl.
Compared to the unweathered loess, the acid forest soil was nearly depleted of its Ca and carbonate‐C contents. A similar, but less distinct, decrease was found in the total profile (Na, Sr, V, Cr, Cu, Zn), or in the soil surface layer only (Mg, Al, Fe, Mn, Ni, Co). Carbon, N, P, S, Pb, Hg, Bi, and Tl accumulated in the soil surface layer.
The input/output balance showed that both forest ecosystems accumulated all elements entering the system with atmospheric precipitation except Al and Mn. The elements Pb, Hg, Bi, and Tl accumulated mainly within the top soil.
In widely different types of Australian soils birnessite and lithiophorite appear to be the common forms of occurrence of mineralized manganese. These mineral forms were dissolved out of the soil by hydrogen peroxide acidified to pH 3 with nitric acid and analyses of the extracts were made. It was found that the concentration of trace elements is generally quite high in these minerals. In particular, most of the soil cobalt (average 79%) was contained in or associated with these minerals where they were present.
On three localities in Denmark, all with 40 to 50 yr old Norway spruce plantations, but different soil chemistry, ion balance studies have been implemented in 1983. The annual variations in soil water concentrations of cations and anions are described and the potential annual leaching fluxes are determined by means of zero-tension percolation lysimeters at 2 depths (A- and B-horizon). Leaching of A1 and and heavy metals was much more severe on the acidic sites, whereas especially Ca was leached from the nutrient rich site. In parallel with the high concentrations of Al and heavy metals, great needle loss was observed on the two acidic sites. The maximum leaching from the A-horizon was obtained either in the late summer, associated with the effluent of organic material, or in the winter due to large amounts of percolation water. Apart from low Ca and kin levels of one of the sites, the findings from the two acidic localities were comparable to similar studies in Sweden.
Die Gehalte an Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd und Pb wurden im Freiland‐Niederschlag, in den Bestandesniederschlägen und im Sickerwasser in zwei verschiedenen Bodentiefen über den Zeitraum von 3 Jahren als gewogene monatliche und halbjährliche Werte in einem Buchen‐und einem Fichtenbestand des Soiling bestimmt.
Der Variabilitätskoeffizient der Konzentrationen und Flüsse innerhalb eines gegebenen Zeitabschnittes liegt häufig über 100%. Es wird vorgeschlagen, zur Ermittlung von zuverlässigen Mittelwerten mit einer hohen Zahl von räumlichen Wiederholungen über mehrere Jahre hinweg gewogene Halbjahres‐oder Jahresproben zu sammeln, um damit die Zahl der notwendigen Analysen einzuschränken und den Fehler des Mittelwertes unter 30% zu drücken. Zur Ermittlung der zeitlichen Variabilität wird die Erfassung von Einzelniederschlägen bzw. von Sickerwasserproben aus kurzen zeitlichen Abschnitten vorgeschlagen.
Humus, representing less than 5% of the dry weight of soil, imparts unique and remarkable properties to the inorganic matrix of sand, silt, and clay. It is to be regarded as a positive asset in crop production. In addition to its well-known effects on physical, chemical, and biological processes in soil, humus plays a key role in the behavior of pesticides and the solution and transport of micronutrients to plant roots. Interaction of humus with organic pesticides and other potentially toxic pollutants and complexation of transitional metal ions, particularly those essential for plant growth are discussed.
Humic materials have been isolated from sea, river and lake waters by an adsorption technique, and the stability constants of their complexes with Ca, Mg, Mn, Co, Ni, Cu, Zn, Cd and Hg have been determined at pH 8.0 using a gel filtration chromatographic technique. In general, the order of increasing strength of binding of the metals followed the Irving-Williams series. The stability constant data have been used in conjunction with the HALTAFALL program of Ingri et al. (1967) to compute speciation models for freshwaters and seawater which take into account metal-humic interactions. In freshwater more than 90% of the copper and mercury was found to be complexed by humic materials. However, <11% of the other metals was bound in this way. In seawater, >99% of the humic material is complexed by calcium and magnesium because of their relatively high concentrations; metal chelation is only appreciable for copper (~10%). The pattern of trace element speciation with inorganic ligands in seawater differs somewhat from that computed by previous workers largely because of the use of more up-to-date stability constant data. Finally, an attempt has been made to compute the changes in metal speciation which would occur when river water becomes diluted with seawater as in an estuary.
Copper activity in saturation extracts (2:1 soil/solution) of sludge- and Cu-salt-treated soil was estimated by ion-selective electrode (ISE) and by Donnan dialysis. Treatments were a factorial combination of four levels of Cu additions and four levels of total sludge additions. In the Donnan system, the ionic strength of a soil saturation extract was matched with KOAc buffer on opposite sides of a cation perm-selective membrane. At membrane equilibrium, Cu concentration was determined in the KOAc buffer by voltammetry. Extracts of sludge treatments had sufficient Cu buffering capacity to maintain the same Cu/sup 2 +/ activity before and after dialysis; Cu-salt treatments exhibited a lower soil solution Cu/sup 2 +/ activity after dialysis indicating the procedure was inadequate for these treatments. The ISE results were more precise, but the technique is only suited for use in aerobic, Cu-contaminated soils. Values for Cu/sup 2 +/ activity obtained by ISE were approximately an order of magnitude greater than Cu/sup 2 +/ activity values estimated by the Donnan dialysis method. By either procedure, increased total Cu resulted in higher Cu/sup 2 +/ activities and conversely, increased total sludge resulted in decreased Cu/sup 2 +/ activities. Total soluble Cu was highest in the Cu-salt treatments; sludge rate was associated with increased soluble Cu and a decreased proportion of free Cu/sup 2 +/.
Deposition of Pb, Cu, Ni, Fe, Mn, and Cd on the McDonalds Branch Basin
in bulk precipitation was 25.4, 5.3, 6.6, 64.6, 20.7, and <2 mg
m-2 yr-1 for a 1 year period in 1978-1979. Output
in streamflow was 1.7, 0.7, 1.9, 148, 12.8, and <1 mg m-2
yr-1, respectively, and loss to deep groundwater was 1.4,
1.9, 2.3, 123, 20.4, and <1 mg m-2 yr-1. Pb,
Cu, and Ni accumulated in the basin, while there was a net loss of Fe
and Mn from the ecosystem. The major mechanism for movement of Fe and Pb
out of the basin was interpreted to be complexation with and transport
by mobile organic matter.
High‐elevation forests receive large amounts of atmospheric lead (Pb) and accumulate it in the forest floor. In order to determine Pb partitioning in a montane, coniferous forest, we analyzed forest floor and mineral soil (Haplorthods and Fragiorthods), and vegetation parts (leaves, twigs, bark, wood) for their Pb content. Soil and stream water were sampled to estimate Pb flux. Mean Pb concentration in trees, in mg kg ⁻¹ , was root bark (33.0), twigs (28.3), bark (23.0) > root wood (10.4) > foliage (3). wood (3). Total Pb in above‐ground biomass (trees + shrubs + herbs) was 0.89 kg ha ⁻¹ . Lead in the organic horizon (forest floor) was 20 kg ha ⁻¹ while Pb in the mineral horizon (E + B) was 63 kg ha ⁻¹ .
Monitoring of soil water for one year yielded volume‐weighted mean Pb concentrations of 3.7, 1.8, 1.1, and 1.0 µ g L ⁻¹ at 3‐, 12‐, 25‐, and 40‐cm depth, respectively. Stream Pb concentration averaged 0.6 µ g L ⁻¹ . We estimated annual Pb input of > 700 g ha ⁻¹ yr ⁻¹ . Estimated output from the forest in stream water was < 12 g ha ⁻¹ yr ⁻¹ . Annual accumulation in the forest floor is approximately 3% of the current forest floor Pb amount. At current accumulation rates, forest floor Pb amount will double in 30 to 40 yr. At current leaching rates, mean residence time of Pb in the forest floor is approximately 500 yr. The ratio of Pb input to output for the forest is 60:1.
Concentration of the heavy metals Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb was measured in different compartments of vegetation and soil in a beech ( Fagus silvatica ) and a spruce ( Picea abies ) forest and the inventory of these elements was calculated. During a period of 3 years the heavy metal concentration in precipitation and soil water fluxes below tree root zone was determined and total element fluxes were calculated.
Annual input from the atmosphere is small (≤30%) for the metals Cr, Mn, and Ni when compared to the amounts stored in the annual increment of biomass. The percentage is higher for Fe (40 to 60%). Uptake of these metals must be supplied partly by weathering of soil minerals. Accumulation of Cu in biomass is completely accounted for by atmospheric input. Total uptake of Co, Zn, Cd, and Pb into the cycling fraction (leaves, needles) and the noncycling fraction (wood) can be accounted for or is exceeded by atmospheric input. Air pollution from industry, home firing, and motor vehicles is the probable source.
Biomass contained up to 27% of total Cd in the ecosystem, but only about 8% of Cu, 2 to 5% of Ni, Zn, and Mn, about 1% of Pb and Cr, and <0.3% of Fe and Co. Accumulation of Pb, Fe, and Co is very strong in the organic surface layer which contains up to 180 times the amount of metal reaching soil as annual litterfall, but only 3 times the amount of Mn, indicating a fast release of the metal by decomposition of organic matter.