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Ge, Ying 1974. "Trace metal speciation and bioavailability in urban contaminated soils." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21555.
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Urban soils are often contaminated with trace metals and the toxicity of the metals depends, in part, on their speciation in soil solutions. The objectives of this project were to estimate the metal speciation in urban soils and to evaluate the predictability of soil metal pools on plant uptake. The chemical speciation of Cd, Cu, Ni, Pb and Zn was estimated by using the Windermere Humic Aqueous Model (WHAM). In soil solutions, Cd, Ni and Zn were present mainly as free ions when the solutions were acidic and their organic complexes were dominant as the pH was over 7.5. The other two metals mostly formed complexes with organic ligands. The activities of Cd2+, Cu2+, Ni2+, Pb2+ and Zn 2+ were affected by soil pH and total soil metal burdens. All five metals were under-saturated with respect to the minerals which could potentially control the metal solubility.Metal uptake by plants in the contaminated railway yards was generally not correlated with free, dissolved and total soil metal pools. A pot experiment demonstrated better correlations between the metal pools and the metal content in wild chicory. Multiple regression analysis showed that the metals in the leaves and roots of wild chicory could be adequately predicted by the soil total metals and soil properties such as pH and exchangeable Ca.
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Khandoker, Rafiqul Alam. "Distribution of Heavy Metals and Trace Elements in Soils of Southwest Oregon." PDXScholar, 1997. https://pdxscholar.library.pdx.edu/open_access_etds/4691.
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Soil samples from 118 sites on 71 geologic units in southwest Oregon were collected and analyzed to determine the background concentrations of metals in soils of the region. Sites were chosen in areas that were relatively undisturbed by human activities. The U.S. Environmental Protection Agency approved total-recoverable method was used to recover metals from samples for analysis. The twenty six metals analyzed were: Ag, AI, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Tl, V and Zn.
The Klamath Mountains followed by the Coast Range contain the highest soil concentrations of AI, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, V and Zn. Soils of the Coastal Plain and High Lava Plains contain the lowest concentrations of these metals. Unusually high soil As concentrations are found at two sites in the Klamath Mountains. All Be and Cd values above laboratory's reporting limits are also from the Klamath Mountains and Coast Range. Concentrations of soil Ba and La are fairly uniform throughout the region. Soil Pb levels are generally low with a few exceptions in the Klamath Mountains, Coast and Cascade Ranges. The region west of the Cascade Range has higher soil Hg contents than in the east.
Soil metal concentrations are generally much higher in the region west of the Cascade Range, excluding the Coastal Plain, than in the east with the exception ofNa, because of more ultramafic rocks and a wetter climate. Soil metal concentrations are directly related to soil development with the highest concentrations being found in well developed Alfisols and Ultisols and the lowest concentrations in poorly developed Entisols. Most metals have similar averages and ranges of concentration compared to the rest of the United States (U.S.). Metals with high values compared to the rest of the U.S. are Cr, Co, Cu, Mn and Ni.
In general, AI, Co, Cr, Cu, Fe, La, Li, Mg, Na, Ni, and V are concentrated in the B horizon while Ba, Ca, Hg, K, Mn, Pb and Zn are concentrated in the A horizon.
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Herselman, J. E. "The concentration of selected trace metals in South African soils /." Link to the online version, 2007. http://hdl.handle.net/10019.1/1390.
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Reyes, Delgadillo Dulce B. "Modeling natural attenuation of trace elements in soils." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101169.
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Trace elements added to the soil by human activities could contaminate it and occasionally cause a threat to environmental and human health. The toxicity and mobility of a trace element are affected by the element's solubility, which in turn is influenced by the soil properties. When mobile, trace elements can be leached out of the soil. If leaching occurs at a faster rate than atmospheric deposition, element concentrations in the soil will decrease by natural attenuation.We analyzed soil properties in 40 soils and their soil solutions to obtain a set of equations with the most significant predictors of As, Cd, Co, Cu, Mo, Ni, Pb and Zn in solution. The total element concentration and the pH were the best predicting variables of the amount of element in solution for all trace elements analyzed, while organic carbon and Al or Mn oxides also influenced the solubility of some trace elements. Using the equations predicting elemental solubility, we wrote a model for natural attenuation in the computer program Stella that considers atmospheric deposition as the input for trace elements and leaching as the output. Simulations were carried out for the 40 soils during 1,000 years with steady deposition inputs.
At current atmospheric deposition rates and the neutral to alkaline pH of these soils, attenuation occurred in most soils for Mo. For As, Cd, Co, Cu and Ni it occurred only in soils with abundant total element concentrations or an acidic pH. Minor retention occurred with Pb and Zn. Only Cd and Cu were of concern in leaching waters. The developed model can serve as a decision making tool in the selection of natural attenuation as a remediation strategy.
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SILVA, Fernando Bruno Vieira da. "Inputs of heavy metals and rare earth elements in soils via phosphate fertilizers and correctives." Universidade Federal Rural de Pernambuco, 2018. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/7319.
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Phosphate fertilizers and corrective are significant sources of soil contamination by heavy metals and rare earth elements, and long-term cultivated soils can accumulate heavy metals above the maximum permissible limits. In this sense, the objectives of the study were (i) to evaluate the potential contamination of Brazilian soils by heavy metals and rare earth via phosphate fertilizers and corrective; (ii) to evaluate the accumulation of heavy metals in soils intensively cultivated with sugarcane, as well as to identify the possible sources of contamination. Initially, were performed total digests of 53 representative samples of P-containing fertilizers and commercialized in Brazil. Concentrations of As, Cd, Cr, Hg and Pb were investigated in fertilizers, which are elements regulated by national legislation. Also the additions of these metals to Brazilian soils were estimated based on the annual consumption and the average concentrations verified in each product. Subsequently, 60 samples of surface soils from areas cultivated with sugarcane were collected, these areas had a long history of use. In the soils, the environmentally available metals (Cd, Cr, Cu, Ni, Pb and Zn) were evaluated, as well as the physico-chemical characterization. The contents of metals in the soils were compared with the guiding values of quality; correlated with soil properties and; subjected to multivariate statistical analyzes to trace the origin of the metals. Finally, the total and soluble concentrations of Ce, La, Nd, Pr, Sm, Sc, Eu, Y, Dy, Gd, Yb, Er, Tb, Ho and Lu were investigated in 60 supplies samples (phosphate fertilizer, and limestone) used in Brazilian agriculture. In addition, the contributions of these elements to Brazilian soils were estimated through the use of phosphate fertilizers and soil correctives. The results of the study showed that Cd in phosphate rocks are the most worrisome, and that in the medium term the heavy metals present in fertilizers containing P do not represent environmental risk. However, the intensive application of phosphate fertilizers in soils cultivated with sugarcane promoted the accumulation of Cd above the guiding values of quality, and in some cases the soils represented a potential risk to human health. With regard to rare earths, it was observed that the solubility of these elements in phosphate fertilizers is dependent on the raw material used in industry (igneous or sedimentary). The annual additions of these elements to Brazilian soils are > 4000 t year-1 and that Ce, La, Nd and Y are the most worrisome. Limestone proved to be a significant source of Gd for agricultural soils. Therefore, soils that continuously receive high doses of these inputs are probably enriched with ETRs.
Fertilizantes fosfatados e corretivos são fontes significativas de contaminação do solo por metais pesados e elementos terras raras, e, solos cultivados por um longo tempo podem acumular metais pesados acima dos limites máximos permissíveis. Nesse sentido, o estudo teve por objetivos (i) avaliar o potencial de contaminação dos solos brasileiros por metais pesados e terras raras via fertilizantes fosfatados e corretivos; (ii) avaliar o acúmulo de metais pesados em solos intensivamente cultivados com cana-de-açúcar, como também identificar as possíveis fontes de contaminação. Inicialmente, foram realizadas digestões totais de 53 amostras representativas de fertilizantes contendo P e comercializadas no Brasil. As concentrações de As, Cd, Cr, Hg e Pb foram investigadas nos fertilizantes, que são os elementos regulamentados pela legislação nacional. Adicionalmente, as adições destes metais aos solos brasileiros foram estimadas baseadas no consumo anual e nas concentrações médias verificadas em cada produto. Posteriormente, 60 amostras de solos superficiais de áreas cultivadas com cana-de-açúcar foram coletadas, estas áreas tinham um longo histórico de uso. Nos solos, os teores ambientalmente disponíveis dos metais (Cd, Cr, Cu, Ni, Pb e Zn) foram avaliados, assim como as caracterizações físico-químicas. Os teores dos metais nos solos foram comparados com os valores orientadores de qualidade; correlacionados com as propriedades dos solos e; submetidos às análises estatísticas multivariadas para traçar a origem dos metais. Por fim, as concentrações totais e solúveis de Ce, La, Nd, Pr, Sm, Sc, Eu, Y, Dy, Gd, Yb, Er, Tb, Ho e Lu foram investigadas em 60 amostras de insumos (fertilizante fosfatado, gesso e calcário) utilizados na agricultura brasileira. Além disso, os aportes destes elementos aos solos brasileiros foram estimados através do uso de fertilizantes fosfatados e corretivos do solo. Os resultados do estudo demonstraram que Cd em rochas fosfatadas são os mais preocupantes, e, que em médio prazo os metais pesados presentes nos fertilizantes contendo P não representam risco ambiental. Contudo, a aplicação intensiva de fertilizantes fosfatados nos solos cultivados com cana-de-açúcar promoveu o acúmulo de Cd acima dos valores orientadores de qualidade, e em alguns casos os solos representaram potencial risco à saúde humana. Com relação aos terras raras, observou-se que a solubilidade destes elementos nos fertilizantes fosfatados é dependente da matéria prima utilizada na indústria (ígnea ou sedimentar). As adições anuais destes elementos aos solos brasileiros são > 4000 t ano-1 e que Ce, La, Nd e Y são os mais preocupantes. O calcário se mostrou uma fonte significativa de Gd para os solos agrícolas. Desta forma, os solos que recebem continuamente elevadas doses destes insumos, provavelmente, estão enriquecidos com ETRs.
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Cook, Nicola. "Bioavailability of trace metals in urban contaminated soils." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34934.
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There are two main components to the research: the theoretical and the experimental. Chapter 2 contains an analysis of the state of soil quality guidelines and the scientific methods used to determine them. A number of recommendations to improve soil quality criteria for trace metals are offered including the importance of considering bioavailability and the need to use realistic conditions, trace metal sources and organisms.A critical review of the literature dealing with predicting the availability of trace metals to plants is presented in Chapter 3. We found little agreement among hundreds of similar studies which relate plant metal uptake to the amount of metal extracted by selective chemical dissolution procedures. An extensive summary of the data shows clearly that the extraction methods are not widely applicable. Differences between individual soils, their metal retention capacities, as well as plant factors and environmental conditions contribute to the variability of the results. Alternative ways of assessing bioavailability are suggested.
The experimental component of the thesis focuses on the availability of trace metals to plants. In Chapter 4 the uptake of Cu from different soil pools was examined and the free metal ion (Cu2+) was found to be the best predictor of uptake by lettuce (Latuca sativa cv. Buttercrunch), ryegrass (Lolium perenne cv. Barmultra) and radish (Raphanus sativus cv. Cherry Belle).
In Chapters 5 and 6 we examined the effect of low-cost in-situ treatments on the availability of metals to plants in greenhouse and field experiments. Synthetic zeolites, P amendments, organic matter and clean soil were used and their effect on the bioavailability of Cd, Cu, Pb, Ni and Zn evaluated. The plants for the experimental work were lettuce and perennial ryegrass. Only the clean soil treatment was consistently effective in reducing the concentration of metals in the plant. We also wanted to determine whether the trace metals in the plant tissue came from the soil or from direct deposition of pollutants on the leaf surfaces. We found little evidence that metals in plants were a result of atmospheric fallout.
A method for the accurate analysis of total metal concentrations in a range of contaminated soils including those containing oil and grease was developed (Chapter 7). For this research the trace metals of concern are Cd, Cu, Ni, Pb and Zn---all commonly found in urban/industrial soils. The proposed method using HNO3/HClO4 has several advantages over the common HNO3/H2O2 procedure. We were able to digest larger soil samples and hence the final concentration of trace metals was usually in the range for analysis by inductively coupled plasma atomic absorption spectrometry or flame atomic absorption spectrometry.
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Andrade, Marc-David. "Development of an on-site ex-situ unsaturated-flow remediation process for trace metal contaminated soils." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85117.
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Innovative means and methods were tested to develop an economical, pragmatic and environmentally sustainable soil remediation process for heavy metal contaminated soils. An unsaturated-flow soil washing procedure was devised to dissolve the soil-bound toxic heavy metals; the latter were extracted by a chemical washing solution that percolated through the soil matrix. Subsequently, the leached toxic heavy metals were selectively concentrated, by a chemical precipitation process, into a solid waste. Thereby, a fraction of the spent ethylenediaminetetraacetic acid (EDTA), within the washing and rinsing leachate, was theoretically regenerated and recycle-ready.The unsaturated-flow washing procedure was perfected by applying different treatments to a soil from a secure landfill. This soil was contaminated with Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, S and Zn. The major contaminants were Fe, Pb, Zn, S, Cu and Mn, making up 25, 1.9, 1.0, 0.4, 0.4 and 0.2%wt of the soil. The extraction responses of the contaminants and those of Al, Ca, Mg and P were established for citric acid (0.5 M) and different molarities of diammonium EDTA ((NH4)2EDTA). The DOW Chemical Company supplied the (NH4)2EDTA (i.e. VERSENE), a 1.37M industrial cleaner, which roughly costs $1.85kg-1 in bulk. The affordability of VERSENE was a pre-condition for hoping to satisfy the economical feasibility of remediating trace metal contaminated soils.
Ultimately, the developed unsaturated-flow washing procedure was tested in a pilot-scale experiment, for its ability to remediate a soil from an abandoned car battery recycling facility. The latter soil was severely contaminated with Pb (3.9%wt). Drip irrigation was used to apply (NH4) 2EDTA and water-rinsing solutions to the surface of soil heaps that rested atop an impermeable barrier, which permitted the retrieval of the leachate. A cumulative EDTA input to the soil of 10.6% wt extracted 49.4% of the total Pb content of the soil. Alternatively, readily biodegradable citric acid barely extracted 2.2% of the total Pb content of the soil, for a cumulative input of 18.1% weight of soil. Different treatments were tested for their effectiveness in concentrating the leached toxic heavy metals into a solid waste. The Pb was best precipitated with Na2S alone, as it provided the most concentrated solid toxic waste.
The environmental sustainability of remediating trace metal contaminated soils was thoroughly examined, as per the amounts of chemical entrants and toxic waste by-products, and per the post-treatment leaching of toxic levels of the remaining and potentially toxic trace metals. (Abstract shortened by UMI.)
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Kennette, Debra. "The bioavailability of trace metals to soil invertebrates in urban contaminated soils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44194.pdf.
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Voigt, Astrid. "Bioavailability of trace metals to plants." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19561.
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Soil quality guidelines are currently based on total trace metal loads. There is a need to define indices of bioavailability to allow reasonable predictions for plant metal uptake and toxicity in soils. Trace metal toxicities to plants often correlate best with free metal ion activities. The first objective was to develop a plant bioassay that is sensitive to trace metals at concentrations realistic for soils. The root elongation of lettuce Lactuca sativa 'Buttercrunch' was used as toxicological endpoint. This endpoint was sensitive and reproducible to environmentally relevant concentrations of Cd, Cu, Ni, Pb and Zn. The second objective was to test whether free metal ion activities are constant predictors of metal toxicities in synthetic solutions and in soil extracts that differ in their concentrations of cations and ligands. The root elongation assay was used to test this hypothesis. In synthetic solutions, the rhizotoxicity of Cd, Cu, Ni, Pb and Zn decreased with increasing Ca and H concentrations. This could not be explained with the effect of higher cationic concentrations on root growth or on solution speciation. It was concluded that Ca and H inhibited the rhizotoxicity of all metals tested. The rhizotoxicity of Cu and Cd was further examined in soil extracts. Both metals became less rhizotoxic at higher H and dissolved organic matter concentrations. The rhizotoxicity endpoints from the experiments in synthetic solution were used to develop parameters for a Biotic Ligand Model (BLM) for Cd, Cu, Ni, Pb and Zn. The BLM accounts for solution speciation and interprets cationic inhibition of rhizotoxicity as competition of metals with Ca and H for potential sites of rhizotoxicity. The BLM predicted metal rhizotoxicity better than the free metal ion activity in synthetic solutions and in soil extracts. Different models were tested against literature rhizotoxicity data for metals at different Ca and H concentrations. Predictions for metal rhizotoxicity given by BLM, Gouy-Chapman-Stern model and Freundlich equation model were compared with predictions based on free metal ion activities in solution. The BLM predicted rhizotoxicity most accurately. The BLM seems promising for predictions of metal toxicity and metal bioavailability in soils to support site-specific environmental risk assessments.
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Williams, Emily Rose. "The Effects of Depth and Hydrological Connectivity on Heavy Metal Loading in Riparian Zones." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185245.
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The area between a stream and land is known as a riparian zone. These zones are highly dynamic whichcarry and accumulate heavy metals and environmental contaminants. Discrete Riparian Input Zones(DRIPs) are a subset of such zones that carry concentrated amounts of water into streams at discrete points.These are more active in their ability to channel water than riparian zones. These areas are important sincethey may retain or release metals and thereby affect the stream chemistry. To test if DRIPs accumulatemetals, 7 DRIPs and 4 Non-DRIPs were sampled along the C5 stream in the Krycklan Catchment. Soilsamples were taken from the surface down to 0.5 m depth at 0.1 m increments and were analysed for totalmercury, metals and loss on ignition. Three metals (vanadin, iron and zinc) were identified as having significant differences in concentration between DRIP and Non-DRIPS. Vanadin and Fe had significantlyhigher concentrations in Non-DRIPs, whereas iron had higher concentrations in DRIPs. Mercury,cadmium, iron, and loss on ignition (LOI) were found to decrease as depth increased, whilst Al was foundto increase with depth. Finally many elements are inter-related, but those with the strongest correlation areLOI and mercury, and iron and cadmium, both r > 0.85. LOI and mercury are strongly related as mercurybinds strongly to organic matter. The relationship of Fe and Cd is likely due to the Fe-oxide and Cdrelationship.
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Tambasco, Giuseppe. "Methods to predict and reduce trace metal levels in lettuce grown on contaminated urban soils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44294.pdf.
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Black, Amanda. "Bioavailability of cadmium, copper, nickel and zinc in soils treated with biosolids and metal salts." Lincoln University, 2010. http://hdl.handle.net/10182/1561.
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It is widely accepted that bioavailability, rather than total soil concentration, is preferred when assessing the risk associated with metal contamination. Despite this, debate continues on what constitutes a bioavailable pool and how to best predict bioavailability, especially in relation to crop plants. The overall aim of this thesis was to assess and validate measures of cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) bioavailability in a range of soils amended with metal salts and biosolids. Six potential measures of bioavailability were investigated and compared: total metal; 0.04 M EDTA extraction; 0.05 M Ca(NO₃)₂ extraction; soil solution extracted using rhizon probes; effective solution concentration (CE) determined using diffusive gradients in thin films (DGT); and modelled free ion activities (WHAM 6.0). These were compared to shoot metal concentrations obtained from plants grown in three soils with contrasting properties treated with biosolids and metal salts. The first study involved a wheat seedling (Triticum aestivum) assay carried out under controlled environmental conditions on incubated soils treated with metal salts and biosolids. Results showed that the presence of biosolids resulted in increases of DOC, salinity, Ca and Mg in soil solution as well as total concentrations of Cu and Zn, dry matter was also adversely affected by increased levels of salinity. The addition of biosolids did not significantly alter the extractability or solubility of Cd, Cu, Ni and Zn although concentrations of Cd in shoots were significantly lower in plants grown in biosolids amended soils compared with unamended soils. The second study involved a field experiment that used 20 cm diameter by 30 cm deep soil monoliths of the same three soils treated with metals and biosolids, and perennial ryegrass (Lolium perenne) was grown for 24 months. Results revealed the addition of biosolids significantly increased the amount of DOC, salinity, Ca and Mg in solution. The presence of biosolids also significantly altered the bioavailability of Cd, Cu, Ni and Zn, as measured by soil solution, CE and free ion activity. However, this change had little effect on plant metal uptake. The length of time following treatment application had the greatest effect on soil chemistry and metal availability, resulting in pH decreases and increases in DOC, soil solution salinity, Ca and Mg. The free ion activities of each metal increased with time, as did soil solution Cd and Zn and CE-Cu, with results for Zn indicative of migration through the soil profile with time. Plant uptake of Ni and Zn also changed with time. Nickel concentrations in shoots decreased, while concentrations of Zn in shoots increased. The findings from the two studies demonstrated that biosolids increased the amount of DOC, salinity, Ca and Mg present in soil solution. In the lysimeter study measures of metal availability were affected in soils amended with biosolids, but this did not effect shoot concentrations. The overall predictive strengths of the six potential measures of bioavailability was investigated using results from the previously described experiments and related studies carried out by ESR and Lincoln University using nine different soils amended with combinations of biosolids and metal salts. Of the four metals Ni provided the strongest correlations between metal bioavailability and shoot concentrations, with 0.05 M Ca(NO₃)₂ extraction giving the strongest relationship for Ni concentrations in shoots (r² = 0.73). This suggests that the solubility of Ni is highly indicative of shoot concentrations and that Ca(NO₃)₂ is a robust measure of Ni bioavailability. In addition Ca(NO₃)₂ provided the best estimate of Zn bioavailability (r² = 0.65), and CE-Cd provided the best measure of Cd bioavailability, although it could only describe 47 % of shoot Cd concentration. Results for Cu were typical of previously described studies as assays of Cu availability are almost always poorly correlated with shoot concentrations, with total Cu having the strongest relationship (r² = 0.34). Methods based on the extractability and solubility of Cu in soils were poor indicators of Cu concentration in shoots. Overall, the addition of biosolids did not alter the outcome of these bioavailability assays, and results indicated that total metal concentrations present in the soils and biosolids matrix, plus length of time since soil treatment, had a greater affect on metal bioavailability.
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Linde, Mats. "Trace metals in urban soils : Stockholm as a case study /." Uppsala : Dept. of Soil Sciences, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/2005111.pdf.
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Ljung, Karin. "Metals in urban playground soils : distribution and bioaccessibility /." Uppsala : Dept. of Soil Sciences, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200681.pdf.
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Taillon, Kate. "Modeling surface complexation relationships in forest and agricultural soil." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82435.
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The adsorption behaviour of trace metals in soil may provide us with a way to more accurately predict and assess the toxicity of metals in the environment. This thesis reports efforts to apply surface complexation modeling to agricultural and forest soil and to relate model parameters to common soil properties. This study considered Ca, Cd, Cu, Pb and Zn but the methods here could be applied to other metals. In Chapter 2, the surface charge and adsorption behaviour of a set of Ap horizons was characterised using back-titration and batch adsorption techniques. With the objective of simplifying the application of the NICCA model to surface charge and cation adsorption in whole soils the parameters of the NICCA model were related to soil properties (Chapter 3). Four of the six surface charge parameters could be predicted from soil properties and this enabled me to reasonably predict the surface charge of a second group of soils from soil properties. These results suggest that it is possible to make reasonable predictions about the surface charge and adsorption behaviour of a given type of soil using some easily measurable soil properties and a set of generic NICCA adsorption parameters for that soil type. In Chapter 4 this idea is applied to the determination of lime requirement for the agricultural soils.
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Herselman, Jacoba Elizabeth. "The concentration of selected trace metals in South African soils." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/1390.
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Thesis (PhD (Soil Science))--University of Stellenbosch, 2007.Trace elements occur naturally in soils, usually at low concentrations (<0.1% or <1000 mg kg-1 of the earth’s crust), as a result of weathering and pedogenic processes acting on the rock fragments from which soil develops (parent material). Since about 98% of human food is produced on land, soil is the primary source supplying these elements to the food chain. Although cases of trace element deficiency and toxicity have been documented in many parts of South Africa, no comprehensive description of trace element concentration has yet been attempted for South Africa as a whole. The Natural Resources Land Type mapping project, initiated in the mid-1970s, has provided a collection of samples (approximately 4500) from soil profiles selected to represent the main soil forms in each land type and therefore to provide representative coverage of most of the soils of South Africa. These archived samples have now been analysed for a spectrum of trace elements, in terms of both available and total concentrations as well as other soil properties. Although detailed information is available on a wide range of trace metals, the seven trace metals considered to be of most interest in a South African context due to natural geological occurrences were selected for this study, including Cd, Co, Cr, Cu, Pb, Ni and Zn. This data was used to: • determine baseline concentrations in SA soils; • determining threshold values for South African agricultural soils receiving sewage sludge at agronomic rates; • determining the influence of certain soil properties on the baseline concentrations of these trace elements in SA soils; and • development of a bioavailable trace element distribution map for SA. The range, the mean and standard deviation (both arithmetic and geometric), and the median were used to summarize the data statistically. The baseline concentration range was calculated using the quotient and product of the geometric mean and the square of the geometric standard deviation, including data below the instrument detection limit. The upper limit of the baseline concentration range was set at the 0.975 percentile value of the population in order to minimize the influence of contamination and the lower limit at the 0.025 percentile value to minimize problems that might be associated with analytical uncertainty near the lower limit of detection. The quantile regression statistical approach was followed to illustrate the relationship between soil properties and trace element concentrations in soils. The soil properties that showed the strongest relation were CEC, clay content, pH (H2O) and S value (base status). The soils were then divided into different classes according to these soil properties and baseline concentrations were derived for the different classes. Soils with low clay contents have lower trace element concentrations than soils with higher clay contents, soils with low or high pH levels have lower trace element contents than soils with intermediate pH values and mesotrophic soils have higher trace element concentrations than dystrophic soils. This information is useful for the compilation of trace element distribution maps for South Africa where different soil forms and series/families could be classified into different classes to determine areas of potential deficiencies as well as toxicities. South Africa, with its diverse geology, has areas of both trace element toxicities and deficiencies and for decision-making purposes it is necessary to identify these areas. Mapping of trace element levels based on soil samples would provide valuable information, which cannot be obtained from geological or geographical maps. Statistical analyses of the data (clay %, base status, pH (H2O) and NH4EDTA extractable trace element concentrations) indicated that soils could be divided into five trace element classes based on their clay content, pH and base status (dystrophic, mesotrophic and eutrophic). The soil series according to the binomial soil classification system for South Africa were then divided into these different classes. The geometric means for each clay class were determined and the baseline concentration range for each class was calculated. The land type maps were used as basis for the distribution maps. A general trace element distribution map for South Africa was derived from this data as well as Cu and Zn distribution maps. A random selection of 500 soil samples across the country was used to verify the accuracy of the distribution map. The general trace element distribution map indicate, with a confidence level between 89 and 96%, where the potentially available trace element content of South African soils are low (deficient) too moderately high, excluding rocky areas and areas with limited soil. The Cu and Zn maps indicate the distribution and expected baseline concentrations of these specific elements in South African soils. The same methodology could be applied to derive risk maps for all the individual trace elements to indicate the distribution and expected baseline concentrations of the elements in South Africa. This presentation of baseline concentrations, reflecting likely natural ranges in South African soils, is the first quantitative report on the spatial extent and intensity of Zn, Cu and Co deficiency in South African soils. The proposal of new threshold values for trace elements in agricultural soils will be valuable in setting more realistic norms for environmental contamination that accommodate the geochemical peculiarities of the region, one example being rather high Cr and Ni concentrations with low bio-availability. This information should be of value not only in environmental pollution studies but also in health, agriculture, forestry and wildlife management. The following recommendations are made: • The baseline concentrations could be used to determine site specific threshold values based on soil properties and soil type. Soils with lower pH, clay content and CEC would require more protection than soils with high pH, clay content and CEC and therefore the threshold levels for these soils should be lower. • Although the distribution maps can be used to indicate broad areas of trace element deficiencies and toxicities, more detailed investigations are recommended for areas where problems are experienced. The same methodology could be applied on smaller scale to increase the value of the map and to add more value on a regional scale. The maps could be used for regional soil quality assessment especially in areas where trace element deficiencies or toxicities could result in negative effects on plants and animals.
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Ge, Ying 1974. "Speciation and complexation of trace metals in eastern Canadian soils." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82879.
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An important task of research on trace metals in soils is to evaluate how much metals are potentially bioavailable and may cause toxic effects. In this thesis, the chemical speciation and complexation of cadmium (Cd), copper (Cu), mercury (Hg) and lead (Pb) were examined in eastern Canadian soils collected from different locations around smelters. Our goal is to be able to predict metal binding in the soil solution and on the solid phase under a wide range of field conditions.In Chapter 2, speciation of Cd, Cu and Pb in the lysimeter soil solutions was determined using an ion exchange technique (IET) involving a resin column. The IET-speciation data were used to estimate the metal-dissolved organic carbon (DOC) binding constants using the non-ideal competitive adsorption (MICA)-Donnan model, which assumed a continuous distribution of binding affinities on the DOC molecule. The published Cd and Pb speciation data in a variety of soils (Chapter 3) were also used to test the effectiveness of two speciation models, the MICA-Donnan model and WinHumicV. Both models satisfactorily predicted the concentrations of Cd2+ and Pb2+. The two chapters of metal speciation demonstrated that the NICA-Donnan model could estimate the binding strength of organic matter in soil solutions.
Proton and metal complexation to the surface of soil particles (Chapters 4 and 5) was investigated using back-titration and batch adsorption procedures. It was shown that the surface binding of H+, Cd2+, Hg2+ and Pb2+ was significantly related to soil organic matter (SOM). Though the soil particle surface was covered by a mixture of organic and mineral components, a two-site distribution could be identified from the titration curves. With the parameters derived from the back-titration and adsorption data, the MICA-Donnan model reasonably predicted the surface complexation of proton and metals. Furthermore, the statistically significant relationships between the model parameters and soil organic matter supported the assumptions in this thesis: (1) Organic matter was the most important sorbent on the particle surface; (2) The MICA-Donnan model may be used to interpret the surface binding data in these soils.
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Reeves, Alastair Ian. "Contaminant tracking through dendro-chemical analysis of tree-radii." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69688.
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The research used dendro-chemical analysis of ash tree rings and current year leaf litter to track Cd, Pb, Zn, Cu, Mn, Cr, and Sn spread and cycling from a closed garbage dump-toxic waste site. This technique allowed for determination of areal extent, contaminant levels and time period of initial contaminant contact. Only Zn, Sn, and Cu were found in elevated quantities in the xylem wood and Pb in the leaf litter. Elemental concentrations of Pb, Sn and Cd in xylem wood and leaves of ash were positively correlated. Tin was the only element to demonstrate a clear initial contact period and elemental accumulation with age. Significant levels of Cu accumulated in the heartwood while Zn revealed significant but inconsistent accumulated patterns. Expected attenuation zones associated with municipal solid waste landfill leachate dispersion were not found; thus the pathway for contaminant dispersion was likely through groundwater flow.An elemental index was developed to facilitate the use of dendro-chemical analysis in periods of suppressed tree growth resulting from environmental pollution.
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MacDonald, James Douglas. "The partitioning of Cd, Cu, Pb and Zn between the solid and solution phase of forest floor horizons in podzolic soils near metal smelters /." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85575.
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The emission of trace metals (TMs) into boreal forest regions of the northern hemisphere is an important environmental issue due to their potential detrimental impacts on these sensitive ecosystems. One of the foremost factors controlling metal cycling is the chemistry of the overlying organic forest floor of the forest soil. In this thesis we examine the chemistry of forest floor horizons of podzolic soils. Our goal is to improve our ability to predict the partitioning of metals between the soil solid and solution phases.We developed a standard protocol to produce solutions that resemble lysimeter solutions from podzolic soils using air-dried samples. We hypothesized that the stabilization point of the electrical conductivity (EC) of the soil solution is indicative of the point in which soluble salts and organic material precipitated during sampling and storage are removed from the soil particle surfaces. Solutions produced by leaching the soils, once the EC of wash solutions had stabilized, were comparable to lysimeter solutions from the area where samples were collected with respect to the concentrations of divalent cations, pH, EC and dissolved organic carbon (DOC). The applicability of this procedure to trace metal partitioning in forest floors was explored. Laboratory extractions produced partition coefficients (log Kd) similar to observed lysimeter solutions ranging from 3.4 to 3.9 for Cd, 3.4 to 3.9 for Cu, 3.4 to 4.1 for Ni, 4.1 to 5.2 for Pb and 3.2 to 3.5 for Zn. According to a semi-mechanistic regression model based on observed lysimeter concentrations, the metal concentrations in solution were appropriate relative to known factors that influence metal partitioning in soils: pH, the concentrations of total metals and DOC.
While chemical characteristics of soils have been consistently observed to play important roles in the partitioning and toxicity of metals we wished to place the importance of the chemical characteristics of soil on mobility and toxicity in context. We interpreted field data that had been collected from transects established with distance from two point source emitters in Rouyn PQ, and Sudbury ON. Canada find developed equations that predict dissolved metal concentrations from total metal concentrations, soil pH, soil organic matter (SOM), and DOC contents. We integrated these equations into a simple box model that calculates changes in the concentration of metals in the organic and upper mineral horizons and includes a loop for vegetative return of metals to the forest floor.
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Li, Juan 1963. "Fractionation and speciation of trace metals in contaminated urban soils from Montreal, Canada." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20266.
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A variety of extractants were used to fractionate the trace metals Cd, Cu, Mn, Ni, Pb, and Zn in contaminated urban soils. The metals were mostly held in soil solid phases but not in soluble and exchangeable forms. Except for Mn, extractability of metals by selective chemicals was mainly a function of the contamination level. The speciation of these elements in water, 0.01 M CaCl2, and pH-adjusted water extra was calculated using the chemical equilibrium model MINEQL+. The free ions of Cd, Ni, and Zn were the predominant species in most of the water and 0.01 M CaCl2 extracts while PbCO30 was the main form of Pb. Organically complexed Cu accounted for over of the total dissolved Cu. The solubility of trace metals increased as solution pH was decreased. Metals Cd, Ni, Pb and Zn combined with Cl- at low pH (<5). Organically complexed Cu was shifted to Cu2+ when pH was decreased.Except for Mn, the activities of the other metals in water, 0.01 M CaCl 2 extracts, and pH-adjusted water extracts were undersaturated with respect to established minerals in soils. MnHPO4 seems to be controlling the solubility of Mn in these extracts.
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Ginnever, Rhoda C. "Soil and plant contents of lead and other trace elements with special reference to the influences of parent rock and pollution." Thesis, Aberystwyth University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324309.
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Gunnarsson, Niklas. "Mineralogical speciation of sulfur in acid sulfate soils from Luleå, Sweden." Thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71759.
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Marine sulfide – bearing sediments that oxidize when in contact with oxygen and leach outelements in high concentrations to small watercourses have been a problem for many years allover the world especially around the Bothnian Bay. The purpose of this study was to furtherinvestigate the sulfur mineralogy present in acid sulfate soils in the area of Luleå, Sweden. Asecondary aim was to see if elements leach out and accumulate in an acid sulfate soil closer tothe recipient. Samples were taken in two profiles (one oxidized and one waterlogged) fromfour sites (sites A-D) and were analyzed for whole rock geochemistry. Two sites were furtherinvestigated for mineralogy in polished samples with an optical microscope, Ramanspectroscopy and SEM-EDS. Each profile consisted of three layers: oxidation zone, transitionzone and reduced zone. The oxidation zone above the groundwater table was light grey withbrown iron hydroxide staining. Parts that lied under the water table were dark grey-black within general strong odor (“rotten eggs”) due to its sulfur content. It was usually straightforwardto distinguish and separate the layers from each other directly in the field, however in somecases pH was needed for confirmation.A general feature of investigated polished samples is the presence of abundant framboidalpyrites that are common in reduced marine sediments. The transition zone was formed in suboxicconditions and this feature is reflected by the mineralogy. Many morphologies of theframboidal pyrite were observed in this layer and signs of both dissolution and formationoccur. In the sample from site C one could observe elemental sulfur in form of large (up to 50μm) euhedral crystals. In the samples with pH<4, no sulfides occur as they have been replacedby jarosite (site B). Site C lacks these sulfur-bearing hydroxides which is thought to be due toa sulfur concentration of <0.2 %. Sulfur shows extensive leaching at most sites but at site B andD1, it accumulates in the transition zone. Elements like cobalt (Co), nickel (Ni) and zinc (Zn)are leached out or are accumulated further down in the profile. Elements that could have beentransported and have accumulated in the waterlogged profiles are Co, Ni, Zn and chromium(Cr) and in some profiles also copper (Cu) and vanadium (V).Coastal watercourses in Bottenviken: Method development and ecological restoration- A cross-border Swedish-Finnish cooperation project
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Araujo, Eloá Moura. "Bioconcentration and desorption kinetic of potentially toxic elements in soils cultivated with horticultural crops in organic and conventional systems." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-18052018-114411/.
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Potentially toxic elements (PTEs) can be absorbed and accumulated in vegetables organ and tissues, and this is an important channel through which PTEs can enter into the food chain. Soil management may interfere in the behavior of PTEs in the system. So, the study of the dynamics of elements in the soil is fundamental to a better understanding of factors that influence soil-plant transfer. In the state of Pernambuco, Brazil, the production of vegetables is mainly concentrated in small or medium organic and conventional farms located in the Agreste and Sao Francisco regions. Our aims in this research were: i) to determine the contents of PTEs in soil and in vegetables produced under conventional and organic systems in garden soils of Pernambuco; ii) to investigate the forms of the PTEs and their uptake by the vegetables based on different soil-plant transfer factors; iii) to use the calculated transfer factors to assess the human risk exposure; iv) to assess the effect of aging and organic matter (OM) on copper (Cu) desorption in garden soils; v) to determine if manure application to soils increases water soluble Cu concentrations; and vi) to verify the efficiency of machine learning techniques in the classification of vegetables produced under organic and conventional systems. Acid and complexing solutions were employed to extract total contents of PTEs in plants and to extract pseudototal, reactive and bioavailable fractions of the PTEs in soils. Soil-plant transfer factors and human risk assessment were calculated based on the determined levels of PTEs. Kinetic assays were developed using rates of organic composts added to Cu-spiked soils to model the Cu desorption. Water extractable Cu and dissolved organic carbon (DOC) were extracted from soils amended with dairy manure, and the Cu-DOC interactions were studied using spectroscopic techniques. Lettuce (Lactuca sativa) leaves had the highest capacity to accumulate PTEs; conventional system promoted higher PTEs values in soils and plants than the organic production; regardless of the scenario, children and adults in contact to vegetables cropped in organic system have a lower health risk than individuals exposed to lettuce leaves conventionally produced. The addition of OM promoted greater Cu desorption, while aging lead to a reduction in the Cu release. The Fouriertransform infrared spectroscopy spectra showed increase in the presence of aliphatic and carboxylic groups in the extracts from the manure-amended soils. Carboxylic acid functional groups on the DOC formed strong bonds with Cu, which can promote Cu transport as dissolved Cu-organic complexes in the soil profile. The Support Vector Machine had an accuracy over 90% to classify the vegetables in the two groups (organic and conventional); and this high assertiveness rate highlights the potential of using elemental quantification and algorithms as support techniques in the process of authenticity and inspection of organic products.Elementos potencialmente toxicos (EPTs) podem estar biodisponiveis para serem absorvidos e acumulados nos tecidos e orgaos vegetais, sendo esta uma importante rota de entrada de EPTs na cadeia alimentar. O manejo do solo pode interferir no comportamento dos EPTs no sistema. Desta forma, o estudo da dinamica desses elementos no solo e fundamental para melhor entendimento dos fatores que influenciam a transferencia solo-planta. No estado de Pernambuco, a producao de hortalicas se concentra em intensos cultivos organicos e convencionais localizados em pequenas ou medias propriedades, principalmente na regiao Agreste e Sao Francisco. Nossos objetivos neste trabalho foram: i) determinar os teores de EPTs no solo e nas hortalicas produzidas em sistemas convencionais e organicos em hortas de Pernambuco; ii) investigar as formas de EPTs e sua absorcao pelas hortalicas com base em diferentes fatores de transferencia solo-planta; iii) usar os fatores de transferencia calculados para investigar o risco de exposicao aos humanos; iv) estudar o efeito do tempo e da materia organica (MO) na dessorcao de cobre (Cu) em solos de horta; v) determinar se a aplicacao de esterco aumenta a concentracao de Cu soluvel em agua; e vi) verificar a eficiencia de tecnicas machine learning na classificacao de hortalicas produzidas em sistemas organicos e convencionais. Solucoes acidas e complexantes foram utilizadas para extrair os teores totais de EPTs nas plantas e os teores pseudototal, reativo e biodisponivel dos EPTs no solo. Fatores de transferencia solo-planta e avaliacao de risco humano foram calculados com base nos teores de EPTs. Estudos de cinetica foram desenvolvidos apos adicao de composto organico em solos contaminados com Cu para modelar a dessorcao de Cu. Cu soluvel em agua e carbono organico dissolvido (COD) foram extraidos de solos adubados com esterco, a interacao Cu-COD foi estudada usando tecnicas espectroscopicas. Folhas de alface (Lactuca sativa) apresentaram a maior capacidade de acumular EPTS; o sistema convencional promoveu maiores tores de EPTs nos solos e plantas do que o sistema organico; independentemente do cenario, criancas e adultos em contato com vegetais produzidos em sistema organico tem um menor risco do que os individuos que consomem folhas de alface convencionalmente produzidas. A adicao de MO promoveu maior dessorcao de Cu, enquanto o aumento no tempo de contato reduziu a liberacao de Cu. Os graficos da espectroscopia de infravermelho com transformada de Fourier mostraram um aumento na presenca de grupos funcionais alifaticos e carboxilicos nos extratos de solos adubados com esterco. Esses grupos funcionais no COD formam ligacoes fortes com Cu, o que promove o transporte do elemento na forma de complexos organicos dissolvidos no perfil do solo. O modelo Support Vector Machine apresentou acuracia superior a 90% na classificacao das hortalicas em dois grupos (organicas e convencionais); e a alta taxa de assertividade mostra o potencial do uso de quantificacao elementar e algoritmos como tecnicas auxiliares no processo de autenticidade de inspecao de produtos organicos.
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COSTA, Welka Preston Leite da. "Metais pesados em solos do Rio Grande do Norte: valores de referência de qualidade e relações geopedológicas." Universidade Federal Rural de Pernambuco, 2013. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5401.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Industrial development and population growth have influenced the heavy metal concentrations in soils as well as impacted the soil quality. In this scenario, environmental protection agencies have been concerned on establishing heavy metal quality reference values (QRV) in order to identify contaminated sites. A first step for QRV establishment is the determination of natural concentrations of metals in soil which represent the metal concentrations with no anthropogenic interference. The work was carried out to determine natural soil concentrations and provide soil reference values for the metals Ag, Ba, Cd, Co, Cr, Cu, Ni, Pb, Sb, V, and Zn in soils of the Rio Grande do Norte state according to the Brazilian legislation. The study analyzed 416 soil samples taken from areas with minimal anthropic interference. These samples were digested by USEPA 3051A method and the metals were measured by ICP-OES or flame atomic absorption (FAA). Positive correlations were obtained for metals with pH, CEC, OC, silt and clay contents. Fe and Mg were found in concentrations higher than other Brazil regions and are due to the parent material high in these elements. The results showed that regional geochemical surveys are essential to establish QRV for heavy metals. For example, QRV for the soils of Rio Grande Norte were more restrictive than QRV adopted for other Brazilian states. The confirmation factorial analysis was useful for obtaining QRV more reliable. Such analysis indicated that these values could be obtained from two replicates only.
O crescimento industrial e populacional tem influenciado os teores de metais pesados nos solos e impactado a qualidade deste recurso. A determinação dos teores naturais é o primeiro passo para definição dos valores orientadores de qualidade do solo, os quais são primordiais para a elaboração de uma legislação direcionada ao monitoramento de metais pesados baseados em uma realidade regional. Neste contexto, as agências de proteção ambiental vêm despendendo esforços para o estabelecimento de índices que possam identificar áreas suspeitas de contaminação. Valores de Referência de Qualidade para Solos (VRQs) refletem a concentração natural de uma determinada substância no solo, sem interferência antrópica. O objetivo desse trabalho foi determinar os teores naturais dos metais Ag, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V e Zn nos solos do Estado do Rio Grande do Norte (RN) e, a partir destes, estabelecer os VRQs para o Estado. Foram coletadas 416 amostras de solo em áreas de mata nativa, com mínima influência antrópica. Caracterização química e física foi executada, bem como, extração de metais pelo método EPA-3051A. Os metais Ag, Ba, Sb e V foram determinados por espectrometria de emissão ótica e Cd, Co, Cr, Cu, Fe Mn, Ni, Pb e Zn por espectrofotômetro de absorção atômica. Correlações significativas e positivas foram obtidas entre os metais e pH, CTC, CO, silte e argila e negativas com os teores de areia. Os teores naturais dos metais Fe e Mn foram superiores aos determinados em solos de outras regiões do país, o que se deve a composição do material de origem do Estado. Os VRQs do Estado do RN (Ag 0,88; Ba 58,91; Cd 0,10; Co 15,41; Cr 30,94; Cu 13,69; Ni 19,84; Pb 16,18; Sb 0,18; V 28,71 e Zn 23,85 mg kg-1) são menos permissivos apresentando maior rigor para o monitoramento ambiental do que os de outros Estados do Brasil. A análise fatorial de confirmação dos dados mostrou-se eficiente para obtenção de VRQs mais confiáveis.
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Khai, Nguyen Manh. "Effects of using wastewater and biosolids as nutrient sources on accumulation and behaviour of trace metals in Vietnamese soils /." Uppsala : Dept. of Soil Sciences, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200774.pdf.
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Vu, Cam Tu. "Comparison between granular and conventional activated sludge for trace metal elements sorption/desorption. Case of copper for landspreading application in France and in Vietnam." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0008/document.
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L'épandage des boues d'épuration est un mode de valorisation à la fois écologique et économique pour autant que l'on maitrise leur qualité et notamment la concentration des métaux lourds mobilisables. Le cuivre est une molécule très répandue, naturelle dans l'environnement, largement utilisée dans l'industrie et l'agriculture. En conséquence, les quantités de cuivre dans l'environnement ont augmenté, de sorte que ce dernier a été choisi dans cette étude comme représentant de la pollution anthropique pour évaluer sa mobilité en fonction de la qualité des boues épandues et des sols. 9 boues classiques et 2 sols (Sol d’herbe (de France) et sol de riz (du Vietnam)) ont été étudiés ainsi que des boues granulaires. Une méthodologie est proposée pour évaluer l'effet de la boue et de l'origine du sol sur la capacité de lessivage du cuivre lors de l'épandage des boues pour les activités agricoles. Les essais de désorption dans les colonnes de sol amendé par des boues ont montré que: a) quelle que soit l'origine du sol amendé, les boues de lit de roseaux (LR), séchées (BCD), centrifugées (BC) ont présenté une libération de Cu inférieure à 2% tandis que les boues de filtre-presse (BFP), digérées (BD), épaissies (BE) et calcaires (BCh) ont amélioré la disponibilité de Cu dans le sol; b) La lixiviation du cuivre dans le sol d’herbe (du France) amendé par des boues granulaires était supérieure à celle mesurée pour les échantillons classiquesde boues; c) Dans le sol de riz (de Vietnam), l'épandage des boues granulaires a limité la désorption de cuivre par rapport aux échantillons de boue (BCh), de filtre-presse (BFP), digérée (BD) ou centrifugée (BC). Quatre mécanismes sont proposés pour expliquer le devenir du Cu dans les sols: 1) le contrôle; 2) le groupe de Cp1, Cp2, BC, LR and BCD; 3) le groupe de BCh, BD, BE, BFP et 4) le groupe de boue granulaire. Il est constaté que pour le sol de riz contenant une faible teneur en matière organique, l'application de boues granulaires ou d'autres types de boue tels que les boues compostées ou séchées peut non seulement augmenter la teneur en éléments nutritifs, mais aussi réduire la capacité de lixiviation du cuivreThe spreading of sewage sludge is both ecological and economical in sofar as their quality is controlled and in particular the low level of the heavy metals available. Copper is a very common substance, naturally occurring in the environment, widely used in industry and agriculture. As a result, quantities of copper in the environment have increased, so it has been selected in this study as representing human-induced pollution to assess its mobility in relation to the quality of sludge and soil. 9 different sludges and 2 soils (grass soil from France and paddy soil from Vietnam) were studied as well as granular sludge. A methodology was developed to evaluate the effect of sludge and soil origin on copper leaching ability during sludge application for agricultural activities. Desorption tests in soil-amended sludge columns showed that: a) Whateverthe origin of soil, the centri-dried (BCD), centrifuged (BC), reed-bed (LR) sludges presented a Cu release lower than 2% while filter-pressed (BFP), digested (BD), thickened (BE) and limed (BCh) sludge amended soils increased Cu availability in soil; b) the copper leaching of granular sludge amended grass soil was higher than those measured for conventional sludge samples; c) in paddy soil, landspreading of granular sludge limited the Cu desorption compared to limed (BCh), filter-press (BFP), digested (BD) and centrifuged (BC) sludge samples. Four mechanisms groups are proposed to explain the fate of Cu in soils: 1) the control; 2) the group of Cp1, Cp2, BC, LR and BCD; 3) the group of BCh BD BE and BFP, and 4) the group of granular sludge. It is found that paddy soil containing low organic matter, application of granular sludge orother types such as composted or dried sludge can not only increase the nutrient content but also reduce the leaching capacity of copper
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Janse, van Rensburg Unique. "Quantification of potential elemental impact of a munitions production and testing facility on its immediate surroundings / Unique Janse van Rensburg." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4575.
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The study attempted to quantify the elemental concentrations and possible accumulation levels in the antelope's organ tissue at Rheinmetal Denel Munitions (RDM), as well as to correlate the findings with the surrounding environment. To achieve this, the elemental concentrations within the kidney, liver and lung tissue of the antelope, and environmental factors such as the soil, vegetation and waterholes were quantified. STATISTICA was used to determine meaningful differences between variables and Canoco to determine the relationship between the different datasets. PCA analyses of the vegetation confirmed that the natural slope at RDM could have contributed to the distribution and variation of the elemental concentration. It became apparent that positive associations existed between the liver tissue and the K, the kidney tissue and Ni and Cd, and the lung tissue had a positive association with Mg, Mn, V, Rb and Co elemental concentrations. It became evident in this study that the elemental concentrations of Al and Ni were higher in the liver and kidney tissue of the antelope than the recommended concentration for livestock (Puls, 1994). The elemental concentration of Al, Ca, Fe and Mn also exceeded the recommended elemental concentration for livestock, in the water sampled at RDM (Puls, 1994). Four distinct areas were identified within the study area, the area above the factory, the area under the factory, the testing area and the area under the factory. Significant differences between the testing area and the area under the factory were found regarding the Tl, Ag, Hg and B elemental concentrations in the vegetation. Furthermore, it became apparent that the amount of precipitation could have contributed to the variation of the elemental concentrations and distribution in the study area as well as in the organ tissue of the antelope.Thesis (M.Sc. (Environmental Science and Management))--North-West University, Potchefstroom Campus, 2011.
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Colombàs, Borràs Margalida. "Nivells d'elements traça i macroelements als sòls de les Illes Balears." Doctoral thesis, Universitat de les Illes Balears, 2014. http://hdl.handle.net/10803/663752.
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[cat] S'estudia l’estat actual del contingut de set macroelements (Ca, Mg, Al, Fe, K, Na i P) i nou elements traça (As, Cd, Co, Cr, Cu, Mn, Ni, Pb i Zn) en els sòls de les Illes Balears. A partir de la determinació del contingut total de macroelements i elements traça mitjançant la digestió de les mostres de sòl per via humida amb aigua règia i s’estudien les relacions que hi ha entre ells i amb les característiques fisicoquímiques del sòl. També s’estudia el comportament dels elements en funció de l’illa, la profunditat i a una sèrie de sòls representatius de les Illes Balears. Finalment, s’estableix una proposta de nivells de fons i valors de referència dels elements traça a les Illes Balears comparant diferents mètodes, amb la finalitat de poder tenir criteris que permetin identificar una possible alteració dels continguts d’aquests elements.
Els continguts medians (mg kg-1) obtinguts pels elements traça estudiats a les mostres superficials han estat: As 15,8, Cd 0,42, Co 9,6, Cr 57,3, Cu 18,7, Mn 467,1, Ni 29,3, Pb 18,7, Zn 53,9. Respecte el comportament en funció de l’illa, el Cd, Co, Cr, Cu, Mn, Ni, Pb i Zn presenten valors més baixos de concentració a Formentera i els més alts a Menorca, amb situacions intermèdies a les altres dues illes, més semblants a Menorca en el cas de Mallorca i més semblants a Formentera en el cas d’Eivissa. L’As no presenta diferències de concentració entre illes. Aquest comportament dels elements traça és invers al del CCE i del pH, així, llocs on tenen un contingut elevat de carbonats tenen un baix contingut d’elements traça.
Les correlacions entre la majoria de paràmetres estudiats són significativament altes (p<0,05) o molt altes (p<0,001). Tot i això, els coeficients dels llims, CO, pH, Na, P i Mg amb la resta de paràmetres són relativament baixos, indicant un baix efecte d’aquests paràmetres sobre els elements traça. Les relacions entre l’Al, Fe, K, As, Cd, Co, Cr, Cu, Mn, Ni, Pb i Zn són altament significatives i presenten majoritàriament coeficients positius elevats entre ells, suggerint un origen comú i natural d’aquests.
Pel que fa l’estudi dels elements traça sobre sòls representatius de les Illes Balears s’ha observat que sobre materials calcaris, els sòls menys diferenciats presenten els continguts més baixos d’elements traça i els més evolucionats són els que presenten els continguts més elevats. Per ordre, els continguts més baixos corresponen als Arenosols de sistemes dunars litorals, seguits de Cambisols sobre margues, Calcisols, Cambisols sobre margues i, finalment, Luvisols com a tipologies més diferenciades i amb continguts d’elements traça més elevats. D’altra banda, sobre les roques olivíniques del Keuper es desenvolupen sòls amb alts continguts de P, Fe, Co, Cr, Mn i Ni i baixos de Cd.
Els rangs de concentració (mg kg-1) de la població de fons dels diferents elements traça per als sòls de les Illes Balears amb el mètode del gràfic de probabilitat han estat: As 2,5-28,2, Cd 0,03-0,74, Co 1,7-16,9, Cr 12,9-95,3, Cu 2,6-32,6, Mn 53,3-793,5, Ni 5,5-49,6, Pb 0,3-34,7, Zn 9,6-96,4. Els valors mitjans de la població de fons han resultat molt semblants amb els cinc mètodes utilitzats. Tot i això, s’aprecia que el rang més ampli de població de fons, i per tant el valor de referència més alt, s’ha obtingut amb el mètode del diagrama de caixes, seguit dels mètodes del rang normal d’una mostra, del de la funció de la distribució calculada, del mètode del gràfic de probabilitat i, per acabar, del mètode de la mediana, amb el que s’obté el rang més estret, i per tant del valor de referència més baix.[spa] Se han investigado 508 perfiles de las Islas Baleares y la variabilidad en ellos de los niveles de macroelementos (Ca, Mg, Al, Fe, K, Na i P), elementos traza (As, Cd, Co, Cr, Cu, Mn, Ni, Pb i Zn) y algunas propiedades del suelo (arenas, limos, arcillas, carbonato cálcico equivalente -CCE-, carbono orgánico, pH y capacidad de intercambio catiónico). Los puntos de muestreo seleccionados presentaban una mínima influencia antropogénica y las muestras de suelo fueron recogidas para cada horizonte de cada perfil. Para el análisis de macroelementos y elementos traza las muestras fueron digeridas usando agua regia y horno microondas. Las concentraciones medias de elementos traza (mg kg-1) obtenidas en horizontes superficiales fueron: As 15,8, Cd 0,42, Co 9,6, Cr 57,3, Cu 18,7, Mn 467,1, Ni 29,3, Pb 18,7, Zn 53,9. Los resultados obtenidos del análisis estadístico revelan correlaciones significativas entre la mayoría de elementos y el contenido de CCE, arcillas y materia orgánica, indicando que las concentraciones de estos elementos se encuentran controladas por las características del suelo. La concentración de elementos traza es relativamente baja en áreas con elevado contenido de CCE, así la concentración de carbonatos en el suelo es un factor determinante en la presencia y distribución de elementos traza en los suelos del área estudiada. Con respecto a la profundidad, se observa un incremento del contenido de arcillas y pH al aumentar ésta y una disminución de la materia orgánica. Respecto los elementos traza, el Cu, Pb Cd, Mn y Zn presentan una disminución en función de la profundidad, mientras que el As, Co, Cr i Ni no presentan diferencias significativas entre los horizontes comparados. Por lo que se refiere a los suelos desarrollados en cada grupo de referencia se encontraron claras diferencias: sobre calcáreas, los suelos poco desarrollados presentan las concentraciones más bajas de elementos traza, mientras que los suelos diferenciados presentan las mayores concentraciones. En orden ascendente de concentración, el menor contenido corresponde a Arenosols de sistemas dunares litorales, seguidos por los Cambisols sobre margas, Calcisols, Cambisols sobre margas y, finalmente, Luvisols como la tipología más diferenciada y con el mayor contenido de elementos traza. Por otro lado, en suelos desarrollados sobre rocas olivínicas del Keuper aparecen altos contenidos de P, Fe, Co, Cr, Mn y Ni y bajas concentraciones de Cd. Por último se estableció la concentración de niveles de fondo y de referencia. Los valores de referencia obtenidos a partir de gráficos de probabilidad fueron(mgkg): As 28,2, Cd 0,74, Co 16,9, Cr 95,3, Cu 32,6, Mn 793,5, Ni 49,6, Pb 34,7, Zn 96,4.
[eng] In this work, 508 soil profiles of Balearic Islands (European Mediterranean region) were investigated, and the variability in the levels of major elements (Ca, Mg, Al, Fe, K, Na i P), trace elements (As, Cd, Co, Cr, Cu, Mn, Ni, Pb i Zn) and some soil properties (sands, silts, clays, calcium carbonate equivalent -CCE-, organic carbon, pH and cation exhange capacity) was examined. Sampling sites with minimal antrhropogenic influence were selected and soil profile samples were analysed for major and trace element content. The soil samples were collected from every horizon in each profile and the samples were digested using aqua regia and microwave oven for pseudo-total trace elements. The median concentrations of trace elements (mg kg-1) obtained in surface horizons were: As 15.8, Cd 0.42, Co 9.6, Cr 57.3, Cu 18.7, Mn 467.1, Ni 29.3, Pb 18.7, Zn 53.9. The results obtained from the statistical analysis reveal significant correlations between most elements and CCE, clay and organic matter contents, indicating that metal concentrations are controlled by soil composition. The trace element concentration is relatively low in areas of high CCE, therefore carbonate concentration in soil is the determining factor in the presence and distribution of trace elements in the soils of the studied area. According to depth, Cu, Pb, Cd, Mn and Zn show an increase with depth, in the same way of clays and pH. As, Co, Cr and Ni do not show statistical differencies between horizons. A clear distinction was found between the metal content of the soils developed in each Reference Soil Group: Over limestones, poor-developed soils show the lowest concentrations of trace elements while well-developed soils have the highest concentrations. In ascending order of concentration, the lowest content correspond to Arenosols of litoral dune systems, followed by Cambisols over marls, Calcisols, Cambisols over marls and, finally, Luvisols as most differenciated tipologies and with higher trace element contents. On the other hand, over Keuper olivinic rocks soils with high concentrations of P, Fe, Co, Cr, Mn and Ni and low concentrations of Cd are developed. The background concentration and reference values have also been stablished. The reference values obtained in this study through probability plots were (mgkg): As 28.2, Cd 0.74, Co 16.9, Cr 95.3, Cu 32.6, Mn 793.5, Ni 49.6, Pb 34.7, Zn 96.4.
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Philipson, Andrew Neil. "Metal binding properties of bacteria from metal polluted soils." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327323.
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Slagle, April. "Background concentrations of trace elements in three West Virginia soils MLRA-126 /." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1380.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains xi, 163 p. : ill. (some col.), maps. Vita. Includes abstract. Includes bibliographical references (p. 72-77).
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Onisiphorou, Christakis. "Stochastic analysis of saturated soils using finite elements." Thesis, University of Manchester, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488082.
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This thesis has investigated the static liquefaction failure, during construction, of the Nerlerk underwater berm. This hydraulically-placed sandfill structure was designed to form part of an artificial caisson island, intended for use as a year-round exploration drilling platform in the Canadian Beaufort Sea. The aim of the investigation has been to examine how liquefaction was possible in a fill which, according to CPT data, was predominantly dilative; in particular, to study the influence, on stability, of 'pockets' of liquefiable material in the sandfill. Instead of a conventional deterministic approach, based on mean strengths, a stochastic type of approach has been necessary, in order to accurately model material heterogeneity. For this research, the double-hardening constitutive model Monot has been used, this being capable of modelling a wide range of material behaviour, from liquefiable to strongly dilative. The material parameters have been calibrated from an extensive laboratory database and expressed in terms of density via the state parameter for sands. The state parameter statistics have been derived, based on a detailed statistical evaluation of an extensive CPT database from the Tarsiut and Nerlerk island sites. These statistics were used for generating uni-variate random fields of state parameter, from which the Monot material parameters could then be backfigured, in order to model the spatial variability in the fill (i.e. heterogeneity). A number of sophisticated stochastic investigations have been performed, using an advanced two-dimensional finite element algorithm encompassing Monot. The results have shown that liquefaction of the Nerlerk berm is consistent with CPT data: i.e. it may be possible for a predominantly dilative fill to liquefy, under static loading conditions, due to the presence of semi-continuous loose zones arising from deposition-induced anisotropy. For such problems, in which material anisotropy is present, a deterministic approach is not appropriate and can be misleading, as this was shown to represent an upper bound response to the stochastic simulations.
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Marzouk, Ezzat Rashad El-Said. "Using multi-element stable isotope dilution to quantify metal reactivity in soil." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/28914/.
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Determining the total concentration of elements in soils seldom provides sufficient insight into trace metal bioavailability. However, measurement of ‘isotopically exchangeable’ metal can provide a better evaluation of metal reactivity and potential toxicity. Traditionally this requires the use of problematic radio-isotopes (e.g. 109Cd (γ)). Fortunately, increasing access to Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in recent years has led to greater use of enriched stable isotopes of trace metals. The lability of heavy metals has been determined through a variety of approaches, including single and sequential extraction or predicted by geochemical models. In the present work, multi-element stable isotopes methods were developed for simultaneously determination of the labile pool of Fe, Zn, Cd and Pb using isotopic exchange principles. This included experimental and instrumental development for an accurate and precise determination of labile metal pool in soils. This approach was then validated by quantifying Zn, Cd and Pb in contaminated soils (Derbyshire; n = 8 and Weardale catchment; n = 246) and comparing the outcome results with common traditional extraction procedures. The variation of metal lability with soil characteristics was used to predict metal lability from the simple soil measurements using a multiple regression approach. In addition, E-values of Fe, Zn, Cd and Pb was used as input to WHAM(VI) (Windermere Humic-Aqueous Model) to predict metal solubility, emphasising in the role of Fe under reducing conditions in this regard. The results showed that isotopic dilution is a robust mechanistic method for assessing the ‘reactive’ pool of multiple trace metals over a wide range of soil characteristics. The results showed a very wide range of metal reactivities (almost 1%-100%) for Zn, Cd and Pb that were consistent over a range of spike concentrations. Sub-micron forms of non labile metal are perhaps most likely to occur in suspension either strongly bonded to humic/fulvic acids or occluded within CaCO3 particles. It appears that E values have no consistent correspondence to any chemical extraction procedure. Nevertheless, the use of 0.43 M HNO3 to extract labile metal in organic soils at pH < 6 appears justifiable - especially where humus is likely to be the principal adsorption surface. It is also important to acknowledge that extractions are not necessarily intended to estimate the entire reactive fraction. Thus, DTPA has been successfully applied as an empirical prediction of plant uptake but its extraction capacity is particularly limited in calcareous systems where it substantially underestimates the isotopically exchangeable metal pool. Speciation calculations showed that prediction of metal solubility was much better when the isotopically reactive metal pools were used as input to WHAM(VI). The soil samples that fitted best had pH values less than 4.0 and high organic matter contents reflecting the strength of the humic binding component of WHAM(VI) particularly in the case of Zn. The changes in metal solubility and lability under reducing conditions were mainly affected by pH. Moreover, the measurement of Fe2+ in the solution phase was considerably lower than that of the isotopically labile Fe2+ which calls into question the dependence on soluble Fe2+ to predict reductive dissolution of Fe-oxides. In addition, under reducing conditions the variables input of Fe to WHAM(VI) showed greatest effects on predicting metal solubility. It was found that Zn and Cd were affected only by Fe2+ competition for adsorption sites while predicted Pb solubility was more affected by loss of oxides than competition processes. The fractionation results, output from WHAM(VI), showed that a significant proportion of Pb was associated with Mn-oxides. Therefore, the calculation of loss of the adsorption site of Mn-oxides depending on Mn2+ measured in the solution phase did not improve the predicted Pb solubility where the model underestimate the adsorbed labile Mn as inference from Fe results.
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Mohamed, Amin Zarinah. "Heavy metal pollution in Antarctic soils." Thesis, University of Canterbury. Department of Chemistry, 1993. http://hdl.handle.net/10092/2879.
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Soil samples from 8 sites (7 contaminated and 1 reference) at Marble Point and Scott Base were assessed for heavy metal pollution. Samples were acid leached and analysed by differential pulse anodic stripping voltammetry and electrothermal atomic absorption spectrometry for lead, zinc, cadmium and copper. Weathering of these metals from point source contaminants was established. Sequential leaching was then performed to evaluate the potential fate ofthe contaminants using the same techniques. Studies were limited to exchangeable fraction and metal fractions bound to carbonates, oxides and organic matter. In the majority of the samples, the oxide fraction formed the largest sink for extractable lead and zinc. In addition, increase in organic matter was observed for some soils. Low levels of extractable aluminium were found, confirming the limited extent of weathering possible in the cold, arid Antarctic climate. Two modes of origin of soluble salts were inferred from levels of sodium, potassium, calcium and magnesium detected in the soils.
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Tejowulan, Raden Sri. "Remediation of trace metal contaminated soils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0030/NQ64679.pdf.
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Dan, Tereza Violeta. "Phytoremediation of metal contaminated soils, metal tolerance and metal accumulation in Pelargonium sp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58302.pdf.
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Teets, Paul D. "Analysis of macro-, micro-, and trace elements of soil samples from Sanborn field /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418071.
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Padmavathiamma, Prabha Kumari. "Phytoremediation and metal speciation in highway soils." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23479.
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Research was conducted to develop a cost effective and environmentally friendly technology to limit the dispersal of metal contaminants from highway traffic in the soil to the surrounding natural environment. The study comprised preliminary field measurements followed by two pot experiments and a field study. The first study evaluated the phytoextraction/ phytostabilisation potential of five plant species: Brassica napus L (rape), Helianthus annuus L. (sunflower), Lolium perenne L (perennial rye grass), Poa pratensis L (Kentucky blue grass) and Festuca rubra L (creeping red fescue) for metals (Cu, Mn, Pb and Zn), in soils with different metal contamination levels. The promising plant species identified were Lolium perenne, Festuca rubra and Poa pratensis. Total soil and plant metal concentrations, as well as the relative metal partitioning in different soil fractions and in plants were determined to provide an estimate of the mobility and potential bioavailability of metals in the soil. The second study evaluated the effectiveness of soil-plant-amendment interaction in immobilising metals in the soil. The amendments included lime, phosphate and compost individually and in combination, and were applied to the plant species: Lolium, Poa and Festuca. Maximum metal immobilisation was achieved in the soil by the combined application of amendments in conjunction with growth of Festuca for Cu, Poa for Pb and Zn and Lolium for Mn. The results obtained from first and second studies were confirmed by conducting field studies. A completely randomized factorial experiment in split plot design with three plant species (Lolium, Poa, and Festuca) individually and in combination, with and without soil amendments was conducted along Highway 17 soil in southwest British Columbia. The influence of root-soil interactions and seasonal influence on the solubility and bioavailability of metals in the soil with and without soil amendments was also evaluated. The best management practices (BMP) developed from the study have the applicability for phytostabilisation of metal contaminated sites and can be suggested as a risk management activity, reducing long-term associated risks.
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Lee, MyungHo. "Electrokinetic remediation of heavy metal contaminated soils." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144895.
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Le, Thi Van Anh. "Characterization of poplar metal transporters to improve rehabilitation of metal polluted soils." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112004/document.
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La phytoremediation consiste à utiliser les plantes pour nettoyer des sols contaminés. Jusqu’ici, des plantes naturellement capables de tolérer et d’accumuler les polluants ont été utilisées pour cette approche. Cependant, l’utilisation de plantes transgéniques doit être considérée pour optimiser l’efficacité de la phytoremédiation. Le peuplier est une espèce adaptée pour la phytoremédiation et peut être utilisé pour des approches transgéniques. Néanmoins, son efficacité de phytoextraction est limitée par une forte accumulation de métaux dans les feuilles qui retournent au sol lors de leur chute. L’ingénierie génétique pourrait être utilisée pour résoudre ce problème, en modifiant l’expression de transporteurs de métaux soit pour limiter l’accumulation de métaux dans les feuilles, soit pour stimuler leur accumulation dans le bois.Dans le cadre de cette thèse, trois transporteurs potentiellement impliqués dans la tolérance et l’accumulation de métaux ont été caractérisés : PtIREG1, PtNRAMP3.1 et PtNRAMP3.2. L’expression de PtIREG1 chez la levure et chez Arabidopsis thaliana a montré que ce transporteur contribue à la tolérance au nickel. Des peupliers transgéniques chez lesquels l’expression de PtIREG1 est globalement augmentée ou ciblée dans le bois ont été générés. Des peupliers transgéniques chez lesquels l’expression de PtNRAMP3.1 ou PtNRAMP3.2 est modifiée ont également été générés au cours de cette thèse. Cela a permis de montrer que ces protéines fortement homologues ont des localisations subcellulaires distinctes : la membrane vacuolaire pour PtNRAMP3.2 et un compartiment connecté à l’appareil de Golgi pour PtNRAMP3.1. Des mesures de concentrations en métaux dans les feuilles des peupliers transgéniques ptNRAMP3.1 et PtNRAMP3.2 ont montré des différences avec le type sauvage non transformé, pour le cuivre, le manganèse, le cadmium et le zinc. Les résultats obtenus contribueront à l’élaboration de stratégies biotechnologiques pour réhabiliter les sols polluésPhytoremediation is the use of plants to clean up polluted soils. Previous approaches have mostly used native plants able to tolerate, degrade and accumulate environmental pollutants such as toxic metals, but transgenic plants may also be considered for phytoremediation in the future. Poplar is well adapted for phytoremediation and suitable for molecular genetic studies. However, high metal accumulation in poplar leaves limits phytoextraction due to toxic metal return to the soil after leaf abscission. In order to circumvent this problem, genetic engineering can be used to limit metal accumulation in leaves or direct metal accumulation in poplar trunks using relevant metal transporter genes under the control of tissue-specific promoters. This thesis focuses on the characterization of 3 candidate metal transporters potentially involved in metal tolerance and accumulation in poplar: PtIREG1, PtNRAMP3.1 and PtNRAMP3.2. Expression of PtIREG1 in yeast and in Arabidopsis thaliana indicated that it contributes to nickel tolerance. Transgenic poplars were generated in which PtIREG1is either ectopically overexpressed or expressed specifically in wood tissues. PtNRAMP3.1 and PtNRAMP3.2 transgenic plants were also generated during this thesis. Despite their high similarity, PtNRAMP3.1 and PtNRAMP3.2 displayed distinct localizations in poplar: PtNRAMP3.2 is targeted to the vacuolar membrane whereas PtNRAMP3.1 localizes in a compartment connected with the Golgi apparatus. Metal concentrations were modified in leaves of transgenic plants grown on metal-contaminated or non-contaminated soil. The results obtained will contribute to develop a biotechnological approach using transgenic plants for the rehabilitation in metal polluted soils
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McShane, Heather. "Metal oxide nanoparticle chemistry and toxicity in soils." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117105.
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Metal oxide nanoparticles (MONPs) are increasingly being incorporated in domestic and industrial products. They are expected to pass into waste water treatment facilities, and may inadvertently be applied in biosolids to agricultural soils. Very few nanotoxicity studies have been conducted in soils and the risk that MONPs pose to soil organisms are poorly understood. The aim of this study was to investigate the behaviour and effects of two MONPs with different solubilities on terrestrial organisms in soils. Exposure of earthworms to soils amended with up to 10,000 mg/kg nano-sized TiO2, a virtually insoluble nanomaterial, resulted in no adverse effects on earthworm population parameters such as survival or reproduction. Earthworms avoided nano-TiO2 amended soils, but only at nanoparticle concentrations higher than those expected for agricultural soils. The mechanisms resulting in the avoidance response, and nano-TiO2 transformations in soils, could not be further investigated because techniques to track nanoparticles in complex media are lacking. Subsequent studies focused on a sparingly soluble nanomaterial, nano-CuO, which releases Cu2+ ions as it dissolves. To identify nanoparticle-specific effects on organisms, the effects of the Cu2+ ions must be determined but little is known about the effect of nano-CuO on Cu2+ activity in soils. Tests revealed that Cu2+ activity in nano-CuO amended soils increased over a 56 d period, but were not comparable to those in soils amended with similar concentrations of micrometer-sized CuO or Cu(NO3)2, which are commonly used as treatments to control for the effects non-nanosized Cu in nanotoxicity tests. These results have implications for the design of experiments that test effects of dissolving particulates. A subsequent barley growth test demonstrated that there was no significant difference in plant growth or shoot Cu concentrations between soils amended with nano-CuO, micrometer-sized CuO or Cu(NO3)2 once growth was normalised to Cu2+ activity. These results demonstrate that release of metal ions can play an important role in toxicity of soluble metal-based nanoparticles and highlight the importance of direct measurement of potentially toxic products of nanoparticle dissolution. There was no evidence of nanoparticle-specific toxicity under the conditions studied either for earthworms exposed to nano-TiO2 or barley exposed to nano-CuO. The study highlighted some of the challenges of understanding the fate and effects of nanomaterials in soils, including the lack of techniques to track nanomaterials in complex media and the difficulty in designing toxicity tests that control for temporal changes to both nanoparticles and soils.Les nanoparticules des oxydes de métaux (MONP) sont davantage incorporés dans les produits domestiques et industriels. Une importante proportion de ces nanoparticules est susceptible de se retrouver dans les usines de traitement d'eaux usées et d'être épandue sur les terres agricoles sous forme de biosolides. Dû au fait que peu de recherches sur la nanotoxicité ont été faites dans les sols, le risque que pose ces MONP aux organismes du sols est peu connu. Le but de cette étude est donc d'observer la réaction et les effets de deux MONP de solubilité différente dans des sols agricoles et artificiels. L'exposition des vers de terre dans des sols amendés avec jusqu'à 10,000 mg par kg de sol de nano-TiO2, un nanomatériel pratiquement insoluble, n'a causé aucun effet sur leur survie ou leur reproduction. Les vers de terre n'ont évité les sols modifiés de nano-TiO2, qu'à des concentrations de nanoparticules beaucoup plus élevées que celles attendues dans les sols agricoles. Les mécanismes impliqués dans la réponse d'évitement et les transformations de nanoTiO2 dans les sols n'ont pu être étudiés plus à fond par manque de techniques développées pour suivre les nanoparticules dans les médias complexes. Dans les recherches subséquentes, un nanomatériel de très faible solubilité, le nano-CuO, qui relâche des ions Cu2+ au fur et à mesure qu'il se dissout, a été choisi comme matériel d'intérêt. Afin d'identifier les effets spécifiques des nanoparticules sur des organismes, les effets du Cu2+ doivent être déterminés. Cependant, peu est connu sur l'activité du Cu2+ dans les sols traités avec des nano-CuO. Les recherches ont démontré que l'activité de Cu2+ a augmenté durant une période de 56 jours pour les sols amendés de nanoparticules de CuO mais cette augmentation ne s'est pas produite, à des concentrations égales, pour des sols enrichis de CuO de diamètre micrométrique ou même de sels de Cu(NO3)2 ; ces deux derniers traitements sont souvent utilisés comme tests contrôles lors d'études de nanotoxicité. Ces résultats ont des implications pour la conception des expériences pour évaluer les effets sur la dissolution des particules. Une étude ultérieure sur la croissance d'orge a démontré qu'il n'y avait aucune différence significative dans la croissance des plantes ou des concentrations de Cu dans les feuilles entre les sols modifiés avec du nano-CuO, CuO de taille micrométrique ou le Cu(NO3)2 une fois que les données furent normalisées en activité de Cu2+. Ces résultats ont démontré que la dissolution d'ions de métaux peut jouer un rôle important sur la toxicité des nanoparticules. Ils soulignent aussi l'importance de mesurer directement la concentration de produits de la dissolution de nanoparticules. Il n'y avait aucune évidence de toxicité spécifique aux nanoparticules sous les conditions étudiées pour les vers de terre soumis au nano-TiO2 ou pour l'orge soumis au nano-CuO. Cette étude a révélé certaines lacunes de compréhension dans le comportement du nanomatériel ajouté aux sols, des difficultés de tenir compte des changements temporels des nanoparticules et des sols ainsi que le manque de techniques disponibles pour suivre les nanoparticules dans les médias complexes.
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Kerr, John. "Phytoremediation of metal-contaminated soils by industrial crops." Thesis, University of Glasgow, 2003. http://theses.gla.ac.uk/5369/.
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Linum usitatissimum (flax), Brassica napus var. oleifera (oilseed rape), Miscanthus x giganteus (miscanthus) and Urtica dioica (nettle) were investigated to assess their potential as phytoremediation crops. Germination experiments using flax and oilseed rape established that seedling germination was not inhibited by exposure to metals in solution except at the highest concentrations considered. Germination was, however, not a reliable indicator of plant metal tolerance as metal toxicity to emerged seedlings was evident in contaminated soil treatments exhibiting good germination rates. Four plant species were grown in soils containing six metals at both highly and marginally spiked levels, to reproduce genuine contaminated soils whilst allowing the study of each metal in isolation. A sewage sludge treated soil with a high metal and organic matter content was also included in the study. Miscanthus was the species most tolerant of the highly contaminated soils. The highest tissue concentrations recorded in plants exposed to the highly contaminated soils were (969 mg Zn/kg) in stems of miscanthus and (919 mg Cd/kg) in stems of nettle, but plant growth in these soils was generally poor. The plant species survived well in the sewage sludge soil, although metal uptake from this matrix was low. Oilseed rape and nettle accumulated the highest tissue metal concentrations in the study of marginally contaminated soils. Indeed the highest tissue concentration recorded for plants grown in all of the soils was found in nettle grown in the marginally contaminated Zn soils (1937 mg/g). Miscanthus, was able to remove a greater weight of metal from the soil owing to its higher biomass, despite having a lower tissue metal concentration than the other species. Flax, miscanthus, nettle and oilseed rape have been shown to have potential to act as part of a phytoremediation programme, however, more work with these crops is required before film advice can be given on commercial application of the crops in contaminated land remediation.
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Svitana, Kevin D. "Using trace elements as an indicator of materials eroded from surface soils." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133194308.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xv, 219 p.; also includes graphics. Includes bibliographical references (p. 112-114). Available online via OhioLINK's ETD Center
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Robson, Thomas. "Weathering of sulfide ores in model soils, potentially toxic element release and bioavailability." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/2859.
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The exploitation of metallic sulfide ores produces vast quantities of fine-grained wastes hosting potentially toxic elements (PTEs). There are concerns that, if improperly disposed of and managed, waste mineral particles can behave as vectors that disperse PTEs via aeolian and fluvial transport, subsequently contaminating soils and crops used to support human populations. The importance of these particles, as sources and influencers of PTE biogeochemistry in productive soils, has received limited research. Long-term (365 d) batch incubation experiments, field weathering experiments and phytoavailability trials, were performed to establish the rate, patterns and factors limiting PTE (Cd, As, Hg) release from grains of sphalerite (Zn(Fe,Cd)S), arsenopyrite (FeAsS) and cinnabar (HgS) into soil matrices (0.1 % mineral:soil m/m), and the bioavailability of the liberated PTEs to important food crops (Tricitum aestivum, wheat and Oryza sativa, rice). All three of the ores underwent chemical weathering in oxic agricultural soils of both temperate and sub-tropical provenance, during which nonessential PTEs (cadmium, mercury, arsenic) were released in bioavailable forms, at rates relevant to agricultural production. Sphalerite weathered at a rate of 0.6 to 1.2 % a-1 (Cd basis) in the experimental soils, releasing 0.5 to 1 μmol Cd g-1 ZnS a-1 into the soil matrix. Cinnabar weathering reached a maximum of 12.0 – 13.5 % (Hg basis) after 90 days exposure in oxic soils, whereas arsenopyrite weathering was rapid and extensive, reaching 56 to 66 % (S basis) after 180 days. The PTE concentrations accumulated in edible grains of wheat and rice grown in the sulfide-contaminated soils were higher than international food safety limits by factors of 8 (Cd in rice), 10 – 30 (Hg in wheat and rice) and 8 – 12 (As in wheat and rice). The primary geochemical factors controlling PTE release and bioavailability were solid-phase associations (i.e. PTEs complexed by clays, metal oxyhydroxides and organic matter) and the precipitation of secondary mineral phases. Weathering arsenopyrite grains were passivated from further oxidation by secondary iron-arsenate phases, which also co-precipitated arsenic liberated from the ore. Secondary phase formation was identified as the cause of decreasing extractable Hg (liberated from cinnabar) after mercury release from cinnabar peaked (≤ 90 days exposure). For sphalerite, the evidence indicates that secondary sulfide phases formed under flooded (sulfate-reducing) soil conditions (paddy rice), limited the bioavailability of cadmium previously liberated under oxic conditions. These key findings demonstrate a potential human health hazard relating to the dispersal of PTE-hosting sulfide ore particles produced by mining activities into soils supporting human populations via crop contamination. This work also highlights differences in ore geochemistry, showing the need for additional research on different ore minerals and their alteration products.
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Vanderspiegel, Rebecca Claire. "Solubility of trace elements in biosolid amended soils, concentrations and controls." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ56376.pdf.
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Aldhaheri, Salem M. "Analysis of trace elements in soils and their uptakes by plants." Thesis, University of Salford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280780.
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Ge, Ying. "Trace metal speciation and bioavailability in urban contaminated soils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0028/MQ50773.pdf.
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Beesley, Luke. "Carbon in urban, brownfield and heavy metal contaminated soils." Thesis, Liverpool John Moores University, 2010. http://researchonline.ljmu.ac.uk/5957/.
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This thesis is comprised of a collection of work on urban, brownfield and heavy metal contaminated soils carried out within the North West of England from March 2007 to December 2009. Field and laboratory based experiments were used to determine the amount of carbon stored in urban soils and fluxes of dissolved organic carbon and soil respiration. The effects of added organic amendments on carbon storage and mobility as well as the onward implications to heavy metals and arsenic mobility and the impact of earthworms on these processes were also investigated. A city-wide topsoil survey of parkland and road verges in Liverpool showed that carbon storage ranged from < 3 to > 10 kg total organic carbon m-2 whilst physico-chemical characteristics and heavy metal and arsenic concentrations also varied considerably. The abundance oftechnogenic material restricted organic carbon storage and flux to the upper 30 cm of an inner city lawn soil studied in greater detail. Brownfield soil carbon storage and fluxes were enhanced by adding a small amount of green waste compost to these soils but large applications did not greatly increase carbon storage further. Enhanced losses of carbon by dissolved organic carbon leaching and increased soil respiration rates were consequences of greenwaste compost additions, although these effects were highly seasonal, occurring in greatest magnitude at the warmest periods of the year. Proportionately, the annual losses of carbon to soil respiration were far greater than those to dissolved organic carbon. An amendment consisting predominantly of woody material and a biochar amendment had a lower impact than composted greenwaste on dissolved organic carbon mobility, and the co-mobilisation of heavy metals and arsenic in a soil from a previously heavily industrialised centre of population. Earthworms reduced dissolved organic carbon when inoculated with compost and biochar amended soil, but increased this soluble fraction of carbon in woody amended soils, with attendant consequence to trace metal and arsenic mobility. Zinc and cadmium mobility were largely independent of changes in soluble carbon, but arsenic, copper and lead were heavily influenced by added carbon. Biochar amendment proved very effective in reducing concentrations of soluble cadmium and zinc in a heavy metal contaminated soil by adsorption, as well as having the added benefit of reducing total and bioavailable polycyclic aromatic hydrocarbon (PAH) concentrations. It is concluded that carbon storage in urban soils can potentially be increased by applying organic amendments, although longer-term carbon storage may only be substantially enhanced with repeated applications of amendments. However, in urban soils with significant residual pollution, it can be questioned whether this practice is environmentally sound, regarding mobilisation of potentially harmful trace elements. Biochar and larger woody fraction amendments to soils may be more efficacious.
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Wu, Shengchun. "Enhanced phytoextraction of metal contaminated soils using beneficial microorganisms." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/589.
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Roane, Timberly Michelle. "Bioaugmentation with metal-resistance microorganisms in the remediation of metal and organic contaminated soils." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/284515.
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Current thinking is that co-contaminated sites (i.e., sites with both organic and metallic pollutants) are difficult to bioremediate because the metal toxicity is such that organic degradation is inhibited. The objective of this research was to evaluate the potential of bioaugmentation with metal-detoxifying microbial populations as a viable remediative approach for such sites. Divided into three sections, this research found that metal-detoxifying microorganisms could facilitate the remediation of co-contaminated systems. The objective of the first study was to compare the microbial community response to cadmium exposure between metal-contaminated and uncontaminated soils. This study found that while cadmium adversely affected the numbers of culturable microorganisms in all soils, cadmium-resistant isolates were found in each soil, regardless of prior metal exposure. However, the metal-contaminated soil microbial communities were more resistant than the uncontaminated soil community. In one metal-stressed soil, resistance increased with increasing cadmium stress. A cadmium-resistant Pseudomonas spp. was found to increase in numbers with increasing cadmium, suggesting a different mechanism of cadmium resistance at high cadmium concentrations. The second study evaluated the diversity of cadmium-resistance/detoxification mechanisms in six cadmium-resistant isolates found in the first study. Genetic and microscopic analyses found several different approaches to cadmium resistance. Two mechanisms known to confer resistance were observed, including exopolymer and biosurfactant production. Two other isolates demonstrated intracellular cadmium accumulation via as yet unknown mechanisms. The mechanism of resistance for one isolate could not be identified. Four out of the six isolates detoxified cadmium as part of their resistance. Since metal detoxification is necessary to allow for organic degradation, these four isolates were included in 2,4-D degradation studies under co-contaminated conditions. The last study examined the use of cadmium-detoxifying microorganisms to enhance organic degradation under co-contaminated conditions. In pure culture and laboratory soil microcosms with cadmium and 2,4-dichlorophenoxyacetic acid (2,4-D) as model contaminants, four cadmium-detoxifying isolates supported the degradation of 2,4-D by the cadmium-sensitive 2,4-D degrader Alcaligenes eutrophus JMP134 in the presence of toxic levels of cadmium. Ina pilot field study, a cadmium-detoxifying Pseudomonas isolate enhanced 2,4-D degradation by A. eutrophus JMP 13 4 in the presence of cadmium.
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Haring, Peter G. "The nature of heavy metal contamination in organic lake sediments near the Buchans massive sulphide base metal mines, Central Newfoundland /." Internet access available to MUN users only, 2002. http://collections.mun.ca/u?/theses,25133.
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