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PULS, ROBERT WILLIAM. "ADSORPTION OF HEAVY METALS ON SOIL CLAYS (KAOLINITE, CADMIUM, MONTMORILLONITE, ZINC)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183889.
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Metal cation adsorption is the predominant chemical mechanism governing the attenuation of toxic metal movement in soils. Clay minerals are the primary adsorbent surfaces in soils due to their ubiquitous nature and large reactive surface area. This study examined the relative affinity of the metals cadmium, nickel and zinc for the clay minerals kaolinite and montmorillonite. The influence which different mineral adsorbents and different complexing ligands in solution have on the adsorption of metal ions was assessed using the Hard-Soft Acid-Base Principle as a theoretical framework for predicting the maximum extent of adsorption and rate of adsorption. The HSAB principle is that hard bases prefer to complex hard acids and soft bases prefer to complex soft acids. The hypothesis that initiated these investigations was that the hard-soft character of mineral surfaces is due to their surface functional groups and can be measured using metal cation adsorption selectivity experiments where pH and complex ion formation are controlled. When complex ion formation in aqueous solution was minimized (i.e. in Ca(ClO₄)₂), adsorption decreased in the order of decreasing softness, CD > Zn > Ni for both clay minerals. Montmorillonite behaved as a slightly harder Lewis base than kaolinite, sorbing the harder Ni and Zn ions to a greater extent than Cd, although both minerals behaved as soft Lewis bases. In the presence of chloride and sulfate ligands, adsorption sequences changed and reflected results from typical soil solution studies. In some cases the adsorption sequences can be explained using the HSAB principle together with computer speciation data and this approach merits further consideration and research. Adsorption over time and calculated adsorption rate constants were generally consistent with equilibrium selectivity data. Adsorption rates decreased in the order Cd > Zn > Ni in Ca(ClO₄)₂ for both clay minerals. The adsorption curves reflect a two-step adsorption process involving a rapid exchange-type reaction followed by a much slower adsorption involving diffusion into the crystal or alteration of the surface through the formation of a new solid phase involving the adsorbed ions.
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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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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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Andong, Omores Raissa. "Spatio-temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in soils in the vicinity of a petrochemical plant in Cape Town." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2432.
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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016.Polycyclic aromatic hydrocarbons (PAHs) are an alarming group of organic substances for humans and environmental organisms due to their ubiquitous presence, toxicity, and carcinogenicity. They are semi-volatile substances which result from the fusion of carbon and hydrogen atoms and constitute a large group of compounds containing two to several aromatic rings in their molecule. Natural processes and several anthropogenic activities involving complete or incomplete combustion of organic substances such as coal, fossil fuel, tobacco and other thermal processes, generally result in the release of the PAHs into the environment. However, the fate of the PAHs is of great environmental concern due to their tendency to accumulate and their persistence in different environmental matrices and their toxicity. Animal studies have revealed that an excessive exposure to PAHs can be harmful. Evidence of their carcinogenic, mutagenic, and immune-suppressive effects has been reported in the literature. In the soil environment, they have the tendency to be absorbed by plants grown on soil being contaminated by the PAHs. It is, therefore, important to evaluate their occurrence levels in different environmental matrices such as soil concentrations.
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Nkqenkqa, Vuyiseka. "Metal and microbial contamination of agricultural soil and the Veldwachters River, Stellenbosch, South Africa." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2423.
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Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2017.Surface water is used as a source of water supply in many countries, including South Africa. One of the sources of surface water pollution is leachate and surface runoff from landfills. In agricultural soils, the landfill runoff and leachate deteriorate the quality and affect the fertility of soil. The entry of metals and microorganisms from landfill leachate to adjacent environments is through surface runoff due to rainfall. Adverse effects on human- and environmental health triggers a need to monitor and control contaminants in the environment. The aims of the study are to determine the effect of landfill runoff and leachate on agricultural soil and river water (Veldwachters River) running adjacent to the Devon Valley landfill site and to identify potential metal-tolerant organisms in environmental samples collected in Stellenbosch, Western Cape, South Africa. Samples (agricultural soil, river water and sediments) were collected once a month for a period of six months from the study area for analysis. Physicochemical parameters that are known to have major effects on environmental samples were assessed and the concentrations of various metals (Al, Pb, Cr, Mn, Mo, Co, Ni, Cu, Zn, Fe, Cd and V) were also determined by means of inductively coupled plasma mass spectrometry (ICP-MS). Soil texture analysis was tested in order to monitor the metal distribution in soils under the influence of environmental factors.
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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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Xiong, Xianzhe, and mikewood@deakin edu au. "Heavy metal accumulation in soils at three field sites subject to effluent irrigation." Deakin University. School of Ecology and Environment, 2003. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050902.110403.
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Three field sites were chosen to study the environmental assimilative capacity of heavy metals in soil. These sites were the Werribee Farm and the Myome Farm in Australia and Shenyang Zhangshi Irrigation Area in China. The Werribee Farm and the Shenyang Zhangshi Irrigation Area received sewage treatment and application on land for a long time. The Myome farm is an experimental site in which investigations on land application of municipal wastewater on water repellent soils is currently being trailed.
Heavy metal contamination, in particular Cr, Cu and Zn, in the Land Filtration soil of Werribee Farm was widespread. More than a century of sewage irrigation has occurred in the Werribee Farm. The temporal distribution pattern of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the soil at this site follow an exponential trend with time and the spatial distribution pattern of accumulation of heavy metals in different paddocks correlates with the number of years of sewage irrigation at that site in the Farm.
Extensive sewage irrigation at Shenyang Zhangshi Irrigation Area resulted in significant Cd pollution in soil-plant (rice) system and poses a significant threat to the health of local people. Even after eight years since cessation of sewage irrigation, the bioavailable fractions of Cd in the soil as analyzed by sequential extraction techniques were very high thus illustrating long-term persistence.
The simultaneous competitive adsorption of metals in water repellent soils (at Myome Farm in South Australia) was studied. In the competitive situation, Cr, Pb and Cu are the heavy metal cations more strongly adsorbed by the soil, whereas Cd, Ni and Zn are the least adsorbed. The increase in Freundlich adsorption capacity by clay amendment suggested that clayed soils are capable sorption of higher heavy metal loadings compared to the non-clayed water repellent soil, which is more vulnerable to heavy metal inputs.
A simple model of environmental assimilative capacity is proposed. The results of comparison of the three field sites shows that the Werribee Farm has a higher environmental assimilative capacity of heavy metals in soil than the soils at Shenyang Zhangshi Irrigation Area and Myome Farm, however heavy metal contamination at Werribee Farm is still a concern. The model of environmental assimilative capacity of heavy metals in soil is an effective tool to assist management of effluent applied land irrigation systems and can be used to better design environmental engineering systems.
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Maleri, Rudolf A. "The ability of terrestrial Oligochaeta to survive in ultramafic soils and the assessment of toxicity at different levels of organisation." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1200.
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Thesis (PhD (Botany and Zoology)) -- University of Stellenbosch, 2006.Metals are natural elements of the earth crust usually present at low concentrations in all soils. Although many metals such as cobalt, copper, iron and zinc are essential to living organisms, at elevated concentrations most metals are toxic to organisms living in and on soils. Elevated concentrations of metals are caused either by anthropogenic deposition following remobilisation from the earth crust or are of natural origin. Ultramafic soils do not only pose unfavourable living conditions such as drought and poor organic content, these soils are also characterized by extremely high concentrations of a range of metals known to be toxic under normal circumstances. Ultramafic soils are of high ecological importance as a high proportion of endemic organisms, especially plants, live on these soils. As it is known that earthworms do occur in ultramafic soils, the aims of the present study were to investigate the abilities of earthworms to survive in these soils and the influences of elevated chromium, cobalt, copper, manganese and nickel levels. For the evaluation of the metal background conditions, soils originating from ultramafic rocks of the Barberton Greenstone Belt, Mpumalanga, South Africa were collected and different fractions representing different levels of bioavailability were analyzed for arsenic, chromium, cobalt, copper, manganese and nickel. To assess the mobile, readily available metal fraction, i.e. Ca2+- exchangeable metal cations, a 0.01 mol/L CaCl2 extraction was performed. To investigate the mobilisable metal fraction, representing the amount of easily remobilisable complexed and carbonated metal ions, a DTPA (di-ethylene-triamine-pentaacetic acid) extraction was conducted. In relation to non-ultramafic or anthropogenic contaminated soils, a far lower proportion of metals were extractable by the above mentioned extraction methods. To investigate the availability and effects of these metals on earthworms, two ecophysiologically different species were employed. Aporrectodea caliginosa and Eisenia fetida were long-term exposed to the ultramafic soils collected at the Barberton region and a control soil from a location at Stellenbosch with a known history of no anthropogenic metal contamination. The responses to the ecological stress originating in the ultramafic soils were measured on different levels of earthworm organisation. As endpoints affecting population development, cocoon production, fecundity and viability were evaluated. On individual level, growth, metal body burden and tissue distribution were investigated. As endpoints on subcellular level, the membrane integrity was assessed by the neutral red retention assay, the mitochondrial activity was measured by the MTT colorimetric assay and as a biomarker for the DNA integrity, the comet assay was performed. Focussing on manganese and nickel, the uptake by E. fetida of these metals was investigated with the exclusion of soil related properties using an artificial aqueous medium to draw comparisons to the uptake of these metals in natural soils. The possible development of resistance towards nickel was tested by exposing pre-exposed (for more than 10 generations) E. fetida specimens to ultramafic soils with concentrations of more than 4000 mg/kg nickel. The results showed that, except on the endpoint survival, which was less sensitive than all other bioassays, significant responses to the ultramafic challenge were observed in all earthworm bioassays and on all levels of organisation. The sensitivity of the responses of the earthworms towards the ultramafic conditions was not predictable by the level of organisation. The two species showed different strategies of metal elimination. In A. caliginosa, metals such as nickel, manganese and chromium were transported to the posterior section and the posterior section was subsequently pushed off by autotomization. In E. fetida, metals such as chromium and nickel were sequestered in storage compartments in the coelomic cells or fluid. Other metals, such as cobalt, were not taken up at elevated concentrations. Although an increased accumulation of nickel was observed in E. fetida specimens pre-exposed to nickel, development of resistance or cross resistance was not observed in this species. In contrast, pre-exposed specimen exposed to elevated concentrations of nickel showed a higher sensitivity in terms of survival, indicating the absence of acclimatisation or even genetic adaptation. A comparison of the two species employed indicated that A. caliginosa was less suited for the assessment of the ultramafic soils due to the high individual variation in metal body burden, the mass loss observed and the slow reproduction rate even in the control soils. This happened despite the fact that A. caliginosa was a soil dwelling species supposed to be better adapted to the soil substrate than the litter dwelling E. fetida. The toxicity of the ultramafic soils was not necessarily related to total or environmentally available amounts of the selected metals. Thus, it can be speculated that either these soils contained unidentified toxicants with resulting interactions between toxicants playing an important role or earthworms were able to remobilize metals occurring in these soils. As the singular application of an ecotoxicological endpoint did not give reliable results, especially seen over the duration of the exposures, it can be concluded that, when studying soils with such a complex composition, the utilisation of endpoints addressing different levels of organisation is necessary for the assessment of toxic stress emerging from these ultramafic soils.
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Li, Wai Chin. "Phytoremediation of heavy metal and PAH contaminated soil : effects of bacterial inoculation on PAH removal, metal speciation, bioavailability and uptake by Sedum alfredii." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/813.
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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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Sheldon, Bonita Joy. "Heavy metal uptake and accumulation in agricultural crops in urban areas of the Western Cape." Thesis, Cape Peninsula University of Technology, 2005. http://hdl.handle.net/20.500.11838/2006.
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Thesis (MTech (Physical Sciences))--Cape Peninsula University of Technology, 2005.A research study into heavy metals in the Cape Town area, found significant amounts of potentially toxic metals such as lead, cadmium, chromium and iron leaching into the underground aquifer. A further additional study conducted on a community garden in Khayelitsha, showed that vegetable crops have the tendency to accumulate certain heavy metals if they are present in soil and water resources. This study was centered around the Philippi Horticultural Area, which is a large significant farming area within the Cape Metropolitan Region. The significance of the study lies in the fact that at least 50% of the local farmers' produce is sold directly to street traders, residents, local supermarket-chains and restaurants. The remainder of the produce is sold at the Epping Market. The purpose of this study was to investigate heavy metal accumulation in various vegetable crop species taken from some of the local farms in the Phillipi Farming area with the objective to: • investigate heavy metal accumulation in various vegetable crop species taken from some local farms in the Phillipi Farming area. • determine the concentrations of heavy metals present in water and soil resource since these will be the primary source of heavy metals to the vegetables. • determine the soil pH and soil organic matter as these two factors would determine the bie-availability ofthe heavy metals. • identify those crops that pose a definite health risk by means of comparing the determined results to the allowed limits.
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Ehsan, Sadia. "Simultaneous mobilization of polychlorinated biphenyl compounds and heavy metals from a field contaminated soil." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100355.
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A major factor complicating the cleanup at many sites is co-contamination by both organic compounds and heavy metals. Whereas much research has focused on the removal of either organic compounds or metals, relatively few studies have investigated simultaneous removal of organic and inorganic pollutants from soil.The studies reported in this thesis have evaluated a novel technique for the simultaneous mobilization of polychlorinated biphenyl (PCB) compounds and heavy metals (HMs) from a field contaminated soil. Soil extraction with washing aids {surfactants/cyclodextrin in combination with chelating reagent(s)} was optimized for mobilization efficiency, recovery/recycle of washing additives, and in parallel detoxification of mobilized contaminants. PCB extraction efficiencies were determined with a method that converted all the PCB congeners to dicyclohexyl by hydrogenation over palladium. Studies demonstrated that 10 minutes of ultrasonic mixing of field contaminated soil with a combination of surfactant (30 mL L-1) or cyclodextrin (100 g L-1) and a sparing quantity (2 mmoles) of EDTA, simultaneously mobilized appreciable quantities of PCBs and most analyte metals (Cd, Cu, Mn, Pb, Zn, Ni, Cr).
Relative to individual reagents, combinations of surfactant (Brij 98, Triton X-301, or Triton XQS-20) or cyclodextrin (RAMEB or HPCD) with EDTA did not influence PCB extraction efficiencies perceptibly. The presence of surfactant or cyclodextrin in admixture with EDTA did not appreciably change the efficiency of mobilization of most heavy metals (Al, Cd, Cr, Fe, Mn, Ni, and Zn) but did increase the recovery of Cu and Pb with nonionic surfactant and cyclodextrin. When coupled with PCB removal by hexane back-extraction and precipitation of the HMs (mediated by hydrolysis of zero-valent magnesium (Mg0)}, aqueous washing suspension was regenerated and recycled twice to mobilize more contaminants from the soil. Three sonication-washes with the same charge of reagent mobilized appreciable quantities of PCBs (68 - 83%) and virtually all of the available Cd, Cu, Mn, and Pb and lesser amounts of the Zn (56%), Ni (59%), and Cr (50%) but only small quantities of Al (28%) and Fe (30%).
The release of EDTA from heavy metals complexes was efficient for most metals (99%) but was influenced by the nature of surfactant. EDTA recovery (62-65%) post three cycles of soil washing, hexane back-extraction, and Mg 0 treatment was similar for all reagent combinations. Among surfactants and cyclodextrin, only anionic surfactants suffered losses to Mg0 treatment.
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Kogoui, Kamta Frederic Noel. "Bioaccumulation and mixture toxicity of aluminium and manganese in experimentally exposed woodlice, Porcellio scaber (Crustacea, Isopoda)." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2677.
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Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2018.Soil ecosystems in urban, rural and agricultural environments receive chemical input from diverse sources of contamination, such as wastewater, industrial discharge, agricultural and urban runoff, fertilizers, vehicle leakages, landfill seepage, and animal waste overspill. Agricultural activities, transportation and industrial activities are suspected to be the highest sources of metal contamination in Cape Town. Although scientists generally have a good understanding of the toxicity of individual chemical pollutants, there is a great need to bridge the gap between our understanding of the toxic effects of exposure to individual contaminants and those effects from exposure to mixtures of chemicals. Woodlice and other soil detritivores have a particularly important ecosystem function in mineralising organic matter. Woodlice experience stress when exposed to toxic levels of metals in the diet, which can reduce feeding rates and may combine with natural stresses to reduce fitness and lower 'performance', thereby possibly resulting in these organisms being unable to completely fulfil their ecological function. The objectives of this study were: to compare how aluminium and manganese are bioaccumulated in Porcellio scaber in terms of the contribution of the hepatopancreas in metal storage compared to the rest of the body; and to determine whether mixtures of aluminium and manganese affect each other’s bioaccumulation and distribution in Porcellio scaber. Woodlice collected from a clean field site (Kirstenbosch Botanical Garden) were experimentally exposed in the laboratory to a range of environmentally relevant aluminium and manganese concentrations. The woodlice were exposed to these metals in single and mixed metal experiments. Oak leaves, collected from a clean site, were contaminated with aluminium and manganese. Therefore, the woodlice were exposed via their food source. A control experiment, where oak leaves were not contaminated, was also prepared. At week 0 and after five weeks of exposure, a sample of the woodlice (5 per exposure group) were dissected to remove the hepatopancreas. Hepatopancreas and rest of the body samples were acid digested and analysed for the metals by means of the ICP-MS. Contrary to the existing knowledge of metals accumulating in the hepatopancreas of woodlice when ingested, this study showed a higher bioaccumulation of aluminium in the rest of the body of woodlice after 5 weeks of exposure than in the hepatopancreas. This result was interpreted as a possible detoxification mechanism by woodlice through the use of the exoskeleton during the moult cycle. A similar result was found when woodlice were exposed to mixtures of aluminium and manganese. This translated to the fact that woodlice were unable to effectively deal with the toxicity caused by the mixture of aluminium and manganese. In the group of woodlice exposed to manganese alone, it was found that manganese concentrations in the rest of the body of woodlice exposed for 5 weeks were statistically higher than the manganese concentrations in the rest of the body of woodlice at the start of the exposure (week 0). However, in the hepatopancreas, there were no statistical differences between the manganese concentrations in week 0 woodlice and the manganese concentrations in week 5 woodlice. Furthermore, manganese concentrations in the rest of the body of week 5 woodlice were statistically higher than manganese concentrations in the hepatopancreas of week 5 woodlice. This was interpreted as further proof that woodlice would accumulate certain metals (aluminium and manganese in this case) in their exoskeleton so that elimination can follow during the moult cycle.
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Hung, Grace Ann. "Metal accumulation in surface sediments of salt marshes in the Bay of Fundy." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98728.
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One of the most recognised values of tidal salt marshes is the ecosystem service they provide as natural sinks for contaminants such as metals. This study examines net accumulation of metals (As, Cr, Cu, Hg, Ni, Pb, Zn and V) over a 5-yr period, from 1997 to 2002, in surface sediments of salt marshes in the Bay of Fundy, Canada. Metal accumulation has been measured in seven sites that extend from outer to inner Bay and in low and high marsh areas within each site. Overall, sediment metal concentrations are at or near their natural levels. Concentrations of metals show variability among marshes but are not significantly different between low and high marsh. Concentrations of As, Hg, Pb and V appear to be influenced by anthropogenic inputs. Calculated sediment loading rates for these metals generally showed gradients of increased loading from outer to inner Bay. Variability in sediment deposition rate is the driving force behind this spatial pattern. Results of this study suggest that the value of salt marshes as a sink for metals may be enhanced by high sedimentation rates.
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Henshel, Judy 1958. "Copper, manganese, and zinc in Puerco River sediments." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276725.
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A study was conducted to test for the presence of heavy metals (Cu, Mn, and Zn) in surface sediments of the Puerco River channel in the aftermath of a toxic spill in 1979 near Church Rock, New Mexico. Analysis of samples from five sites downstream from the spill showed that these substances were not present in unusually large amounts, though an increasing gradient of metal concentration with distance downstream was revealed. Statistical analysis revealed the Cu, Mn, and Zn were associated with clay and silt, soil organic matter, organic carbon, and carbonates, all of which existed as extraneous, uncontrolled variables. Adjusted metal concentrations, obtained with covariate analyses, confirmed the increasing gradient downstream. Clay and silt also increased downstream. Some toxic substances may have leached into the riverbed; possible mechanisms for this process are also discussed and further study to substantiate or disprove this hypothesis is recommended.
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Kwok, Chun Kit. "Toxicological assessments of PAHs, OCPs and heavy metals in sediments at Mai Po and Deep Bay, Hong Kong." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/875.
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Clegg, Yolanda. "Historical inventory of sedimentary carbon and metals in a Bay of Fundy salt marsh." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30357.
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In 1996, four cores (∼30 cm depth) were extracted from the high marsh zone of Dipper Harbour salt marsh in the Bay of Fundy. Soil bulk densities are shown to be controlled by mineral density and are higher than those reported for salt marshes in the northeastern United States. Examination of variations in mineral content suggests that regular tidal action and ice rafting deposits the majority of the mineral sediment to the high marsh zone. Dating techniques (based upon pollen, 137Cs, 210Pb and total Pb) were applied to selected cores, suggesting accretion rates from 0.25 to 0.31 cm yr-1 which are higher than the rates of local relative sea level rise. Correlation of trace metal densities (Cu, Fe, Pb and Zn) to Al densities were used to justify Al normalization. After consideration of natural sources and adsorption factors, the normalized Pb profiles are shown to reflect historical pollution levels of leaded gasoline consumption. Carbon storage values in the upper 25 cm of sediment range from 7.3--10.5 kg C m-2 and carbon accumulation rates vary from 95 to 124 g C m-2 yr-1, representing 15--29% of the salt marsh macrophyte productivity.
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Ekumankama, Chinedu. "Effect of heavy metal co-contamination on the biodegradation of polycyclic aromatic hydrocarbons in an urban soil with high organic carbon content." Thesis, Northumbria University, 2015. http://nrl.northumbria.ac.uk/30323/.
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Biodegradation is a commonly used approach for the removal of organic contaminants from soil, relying on naturally present microorganisms that utilise the pollutants as an energy source. Often these sites are co-contaminated with heavy metals and the aim of the current research was to investigate how this affects the biodegradation of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs), both in terms of removal rates and the overall functioning of the soil microbial community. Soil samples were obtained from a Greenfield site in Newcastle upon Tyne. The soil had a high organic content (11.0 %) and also contained elevated lead concentrations as a result of past atmospheric deposition from adjacent industrial activities. PAHs were applied to the soil using a coal tar source dissolved in acetone, giving a total PAH concentration in the spiked soil of 2166 mg kg-1. Individual PAH concentrations ranged from 1.44 mg kg-1 (acenaphthylene) to 325 mg kg-1 (benzo[b]fluoranthene); the benzo[a]pyrene concentration was 255 mg kg-1. The effect of heavy metal co-contaminants on the biodegradation was investigated using separate amendments of cadmium and lead to give respective total concentrations ranging from 133 to 620 mg kg-1 and 340 to 817 mg kg-1. Mercury amendment was used to give an abiotic control. The study was carried out over 40 weeks. For all treatments, the degradation of PAHs was observed to be biphasic. A novel kinetic model was developed to explain this dependence. In the absence of metal amendment, it was found that PAHs comprising two and three benzene rings generally degrade at a faster rate than four- five and six-membered rings. In the presence of metal amendments, overall % biodegradation after 40 weeks is relatively unaffected for two to four-ring PAHs but shows significant impairment for five and six-ring PAHs. Nevertheless, degradation rates generally decrease with increasing metal concentration, as do soil respiration rate, Shannon Diversity Index, and microbial biomass content. Lead appears to exert the greatest inhibitory effect. The novelty of this study arises from the integrated approach to investigating the effect of metal co-contaminants on the biodegradation of all 16 US EPA priority PAHs together with parameters relating to the functioning and diversity of the soil microbial community.
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Aelst, Sébastien van. "Etude fonctionnelle des gènes plasmidiques de résistance au cuivre de Cupriavidus metallidurans: aspects physiologique, biochimique et écologique." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210529.
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Cupriavidus metallidurans CH34 est la bactérie Gram négative considérée comme organisme-modèle pour l’étude de la résistance aux métaux lourds. Notre travail a porté sur sa résistance au cuivre, codée par les gènes cop du plasmide pMOL30. Ces gènes, responsables des différentes étapes de la résistance (compartimentation des systèmes d’efflux entre périplasme et cytoplasme, modification de valence, et d’autres fonctions totalement inconnues) ont suscité notre intérêt.On distingue dans l’îlot cop des gènes codant pour des fonctions de résistance proprement dite (essentiellement par détoxication active du cytoplasme et du périplasme). En effet, les mutants de copSRABCD, copF, et dans une moindre mesure copJ et copE deviennent sensibles. Les phénotypes des mutants divergent toutefois suivant que la mutation soit sur un cosmide qui ne porte que l’îlot (pMOL1024) ou dans son plasmide d’origine (pMOL30). Un second groupe de mutants (copVTMK, copG, copL, copQ) se distingue par un phénotype plus résistant ou identique à la souche parente, sauf autour de la CMI. Ces gènes interviendraient donc à la CMI pour assurer la résistance la plus élevée et le maintien d'un état viable latent.
La présence de l’îlot cop permet de contenir le taux d’oxygène radicalaire qui reste à un taux basal lorsque les cellules sont adaptées au cuivre environnent. Après un choc de Cu (ou stress aigu), l’îlot cop répond de façon « explosive » au stress, en consommant l’énergie du potentiel membranaire et en augmentant fortement l’activité de la chaîne respiratoire.
La résistance au cuivre est inductible, mais de façon différenciée pour la souche sauvage (CH34) et celle qui ne porte qu l’îlot cop (AE1744) :la CMI de CH34 triple après adaptation au cuivre, alors que celle d’AE1744 est inchangée. Après un choc de Cu, la résistance au cuivre est plus fortement induite pour AE1744 que pour CH34. Ces observations suggèrent que l’îlot cop ait été sélectionné pour sa capacité à répondre à un stress aigu puis intégré dans un ensemble de gènes plus vaste qui répond à des impératifs de stress chronique.
L’analyse biochimique de CopI, une petite protéine bleue à cuivre, montre qu’elle porte un site analogue à celui des oxydases multicuivre. Son rôle pourrait dès lors être celui d’une réductase multicuivre. La protéine CopK lie de façon très spécifique le Cu(I) et il semble que la liaison du cuivre modifie sa structure. L’analyse écologique a montré que des homologues de copK pourraient être présents dans l’ADN extrait de la terre de biotopes chargés en cuivre, et dans les souches cuprorésistantes qu’on y trouve.
La contribution majeure de cette thèse est de montrer que l’effet d’un stress métallique ne se résume pas à deux états physiologiques « mort ou vif ». Il y a lieu de considérer des états transitoires (choc de Cu, adaptation au métal, survie autour de la CMI, persistance) où interviennent des gènes spécifiques dans un ou plusieurs états donnés. Les résultats biochimiques et physiologiques ne nous éclairent pas encore assez sur les interconversions Cu(I)/Cu(II) ni sur les flux de cations notamment vers l'espace extracellulaire. Cette thèse ouvre des perspectives sur des mécanismes (protection à la CMI, phénotype persistant) assurant la survie des bactéries ou leur potentiel de recolonisation lors d'une diminution de la pression toxique :les gènes copT, copV, copK, copM, copB, copG, copL et copQ semblent impliqués dans ces fonctions.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
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Wheal, Matthew Simon. "The influence of chlorsulfuron on the uptake and utilization of zinc by wheat /." Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phw556.pdf.
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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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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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Souza, Lucas Anjos 1985. "Potencial fitorremediador de leguminosas herbaceas associadas a fungos micorrizicos arbusculares em solo contaminado com chumbo." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315654.
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Orientadores: Marlene Aparecida Schiavinato, Sara Adrian Lopez de AndradeDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-15T17:24:07Z (GMT). No. of bitstreams: 1 Souza_LucasAnjos_M.pdf: 3027770 bytes, checksum: b8bcb5d45029d8dc57eac08831f2233d (MD5) Previous issue date: 2010
Resumo: O desenvolvimento de novas tecnologias, para exploração do meio ambiente, está intimamente relacionado ao aumento da poluição ambiental, principalmente por metais pesados (MPs). O mais preocupante é quando a contaminação por MPs ocorre em solos agriculturáveis e leva, conseqüentemente, à contaminação de animais e seres humanos. O Pb é um MP que é cumulativo nos organismos vivos e não possui nenhuma função fisiológica vital conhecida até o momento. Esse elemento está presente em baixas concentrações quando o solo não sofreu influência humana. Existe uma grande preocupação em recuperar áreas contaminadas com MPs, mas diversas técnicas empregadas são muito laboriosas e caras. Uma alternativa seria a utilização da técnica de fitorremediação, na qual se utiliza plantas com capacidade de absorver e acumular grandes quantidades do contaminante em seus tecidos para, posteriormente, coletá-las e estocá-las em locais seguros. De uma maneira geral a associação de plantas com fungos micorrízicos arbusculares (FMA) altera a fisiologia da planta e dessa maneira o potencial fitorremediador pode ser acentuado. O objetivo desse trabalho foi investigar como a associação com o FMA Glomus etunicatum pode influenciar o crescimento e o potencial fitorremediador de Canavalia gladiata, Stizolobium aterrimum e Calopogonium mucunoides em solo contaminado com chumbo. Esse experimento foi conduzido utilizando-se as 3 espécies de leguminosas herbáceas citadas acima, inoculadas ou não com FMA, crescendo em diferentes concentrações de Pb (0, 250, 500 e 1000 mg kg-1) adicionado sob a forma de acetato de chumbo. Observou-se que a germinação das sementes de nenhuma das espécies estudadas foi afetada pelo Pb no solo. No entanto, o crescimento da parte aérea e das raízes foi afetado diferentemente em cada uma dessas plantas, sendo C. mucunoides a que sofreu mais com a presença de Pb no solo. A micorrização teve um papel importante na tolerância de C. mucunoides ao Pb, enquanto que nas demais espécies tal efeito não foi observado. A micorrização favoreceu o acumulo de Pb em C. mucunoides e em C. gladiata mas não em S. aterrimum. Todas as espécies estudadas apresentaram potencial fitoestabilizador de Pb; C. mucunoides apresentou menor translocação de Pb para a parte aérea que C. gladiata e S. aterrimum. A micorrização se mostrou fundamental apenas para o desenvolvimento de C. mucunoides na presença de Pb
Abstract: The development of new technologies, to the exploration of environment, is intimately related with the increasing environmental pollution, mainly by heavy metals (HMs). This scenario can become more serious when the contamination by HMs involves agricultural soils and results in contamination of crops used in human consumption and it lead to the contamination of animals and human beings. Pb is a HM that is accumulative in the living organisms and it doesn't possess any vital physiological function known until the present. This element is present in the soil in low concentrations when the soil hasn't suffered human influences. There is a great concern in recovering polluted areas with HMs, but several employed techniques are very laborious and expensive. An alternative would be the utilization of the phytoremediation technique that involves the use of plants with capability to absorb and accumulate great amounts of the pollutant in their tissues to, afterward collect and store them in safe places. In a general maner the association of plants with arbuscular mycorrhizal fungi (AMF) alters plant's physiology and, thus the phytoremediation potential can be enhanced. The objective of this work has been to investigate how the association with the AMF Glomus etunicatum can influence the growth and the phytoremediation potential of Canavalia gladiata, Stizolobium aterrimum and Calopogonium mucunoides in a soil contaminated with lead. This experiment was carried out using the 3 species of herbaceous leguminous mentioned above, inoculated or uninoculated with AMF, growing in different Pb concentrations (0, 250, 500 e 1000 mg kg-1) added as lead acetate. It was observed that the seeds' germination of all the studied species was not affected by Pb in the soil. However the growth was affected differently in each one of the species where C. mucunoides was the one that suffered more with Pb in the soil. The mycorrhization had an important role in the tolerance of C. mucunoides to Pb while in the other species we haven't observed such effect. The mycorrhization favored the accumulation of Pb in C. gladiata and in C. mucunoides but not in S. aterrimum. All the studied plants presented phytostabilization; C. mucunoides presented lower translocation of Pb to aerial parts than C. gladiata and S. aterrimum. The mycorrhization demonstrated it self fundamental only to the development of C. mucunoides in the presence of Pb
Mestrado
Biologia Vegetal
Mestre em Biologia Vegetal
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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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Atkinson, Nikola R. "Heavy metal geochemistry of contaminated fenland soils in NW England." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/27795/.
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The use of peri-urban fenlands for agriculture usmg urban waste as manorial treatments is increasingly common worldwide, particularly in developing countries. The risk to human health from the use of these contaminated materials for crop production has been studied using two historically contaminated fenlands in NW England. The GBASE survey carried out by the British Geological Survey identified two areas of metal contaminated fenland; west of Manchester (Chat Moss) and north of Liverpool (Halsall Moss). The two areas are used for arable agriculture, and current demand for locally sourced food is increasing pressure on farmers to move to vegetable horticulture. The effect of the metal contamination on the soils and crops is of key importance to monitor any risk to the food chain. Historical research identified the two mossland areas as contaminated with urban wastes, Halsall Moss contaminated with urban organic wastes such as manure and Chat Moss contaminated with urban organic and mineral wastes. Waste disposal on Chat Moss was carried out by the Manchester Corporation to dispose of city waste and generate farmland from the peat. During the drainage up to 1.92 Mt of waste was incorporated into the soil, representing 38% of the topsoil today. Profiles of contaminated and control sites on Chat Moss and a contaminated site on Halsall Moss were collected, with pH, organic matter content and trace metal content measured. Trace metal content was elevated over subsoil levels in the topsoil of all sites, for example arsenic showed topsoil concentrations of 45 mg kg-I in the most contaminated site (CM-3) compared to 3 mg kg-I in the subsoil. The elevation of trace metals in the historically uncontaminated sites indicated possible atmospheric deposition of metals at the control site. Contamination levels were found to be less than originally identified in the GBASE survey, possibly due to differing sample preparation methods and survey size. The GBASE survey measured an average lead concentration in contaminated sites of 1985 mg kg-I compared to 378 mg kg-I measured by the current study. Arsenic and cadmium concentrations exceeded Soil Guideline Values in the most contaminated site, 43 mg kg-I and 1.8 mg kg-I respectively, but all other metals were within guideline limits. Halsall Moss was found to be less contaminated than Chat Moss, due to the mainly organic nature of the waste disposed at Halsall Moss. The mobility and fractionation of the contamination at the most contaminated site on Chat Moss were studied to understand the behaviour of the metals and assess potential risk to ecological or human health. Using sequential extractions, most metals were identified as hosted by organic, Fe/Mn oxide or residual phases. There was no difference observed in fractionation between control and contaminated sites, indicating that soil properties such as organic matter and Fe/Mn oxide content were more important in controlling fractionation than the source of metals. A comparison of Chat Moss with three soils of known contamination history also identified soil properties as key in controlling fractionation. Lability of Pb in the contaminated Chat Moss soil was assessed using 204Pb stable isotope dilution, it was found that 65% of lead was labile. This was the highest out of the four soils studied, and again most likely controlled by soil properties such as organic matter content and pH. The impact of flooding events on the Chat Moss soils was assessed, and it was found that under redox conditions of -200 mY, large quantities of arsenic, lead, molybdenum and manganese were released to soil solution, and drinking water limits for these metals were violated, for example As solution concentration reached 308 J.1g L-1 and the drinking water limit is 10 Ilg L-1. Environmental quality standards for freshwater were also violated by arsenic, copper, lead and zinc showing potential ecological hazard under these reducing conditions, with lead concentrations reaching 137 J.1g L-1 in contrast to the environmental quality standard of 4 - 20 J.1g L-1. The effect of soil contamination on vegetables grown on Chat Moss was also investigated, EU limits for Cd were exceeded by lettuce and onion, and EU limits for Pb were exceeded by parsley, carrot, radish and onion. Hazard Quotients used to assess the impact of plant contamination in the context of human intake showed that only cadmium and molybdenum were potentially hazardous. Thus it is not recommended to grow lettuce (high Cd), parsley, cabbage, radish and onion (all high molybdenum) at contaminated sites on Chat Moss. To minimise risk, conducting liming to raise the pH and immobilise the metals could be used, and careful selection of cultivars that do not accumulate metals is recommended.
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Antoniadis, Vasileios. "Heavy metal availability and mobility in sewage sludge-treated soils." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298663.
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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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Kalumba, Denis. "Remediation of heavy metal contaminated fine grained soils using electrokinetic geosynthetics." Thesis, University of Newcastle Upon Tyne, 2006. http://hdl.handle.net/10443/741.
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Among the most promising novel methods for treating heavy metal contamination in fine soils is electrokinetic soil remediation - passing a low-voltage current through the soil that causes the target contaminants to migrate to the electrodes where they can be captured, broken down or immobilized. However, the widespread in-situ application of this process as a creative solution for the problem of metal contamination has been prevented because of a variety of problems, some of which are linked to the available electrodes. The limitations related to the available electrodes include: corrosion of the anodes difficulties in removing contaminated water and gases from the electrodes poor electrical contact of electrodes with the soil, cost of producing functioning electrodes, and limitations related to the physical form of the electrodes. Many of these historical limitations have been eliminated by the introduction of Electrokinetic Geosynthetics (EKGs) which combine electrokinetics with geosynthetics technology to create geosynthetice lectrodes. In this investigation, the use of an EKG system to capture and dispose of zinc ions from kaolin soil is evaluated by conducting extensive labor4tOry tests using specially designed bench scale tanks. A comprehensive test programme was established to include two electrokinetic remediation removal approaches: One Process Approach and Two Process Approach. The former was achieved by electro, migration of metal contaminants towards the cathode electrode without any external enhancement agent while the latter combined soil flushing with the electrokinetic process. The testing technique enabled the study of effects of. water flushing, soil depth, intermittent currents and replenishing draining chambers along the soil profile with deionised water, on the efficiency of cation removal. The respective responses were primarily presented in terms of electrical current/test duration, water content/test duration, zinc concentration/normalised distance from the anode, zinc concentration/ test duration and pW normalised distance from the anode. Results indicated that the EKG system has a lot of potential for cleaning up soil at sites contaminated by heavy metals and other harmful compounds. The in-depth analysis also showed clearly that combining the technique with soil flushing improved the effectiveness of the treatment operation. The study considerably extended the understandinogf the performance of electrokinetic technology particularly in fine grained soil and are as where further research would improve this understanding were highlighted.
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Morrison, Jason T. "Heavy metal redistribution in soils using compost as a soil amendment." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1307.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains vii, 38 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 34-36).
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Dyer, Mark. "Examining barriers to phytoremediating heavy metal polluted soils in developing countries." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-36751.
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Heavy metal soil pollution from anthropogenic sources such as historical use of fertilizers, poor waste disposal, and spills from industries are a serious environmental problem. This can be especially damaging in developing countries where incentives are limited to remediate these soils, and some of the poorest regions are the most affected. Soil remediation can clean heavy metal polluted soil to a level that is sustainable for the environment and the organisms that inhabit it. Many conventional soil remediation techniques can be very expensive, and resource and energy intensive, making them poor choices for developing countries. However, phytoremediation, an emerging soil remediation technology, is much cheaper and less intensive by using the natural ability of certain plants to clean polluted soils. Although phytoremediation has been considered the best available technology for developing countries with heavy metal polluted soil, it is still being underutilized. In this thesis, through the examination of case studies from the U.S., several barriers are identified that are preventing further implementation of phytoremediation projects in developing countries. These barriers include, the difficulties for developing countries in recognising the scale of heavy metal pollution, a lack of enforcement of environmental legislation and standards, prohibitive costs of projects, problems with the effectiveness of phytoremediation as a soil remediation technology, and a lack of technological knowledge.2018-10-30
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Magno, Melissa A., Ingrid Luffman, Arpita Nandi, and Brian G. Evanshen. "SPATIAL INTERPOLATION OF HEAVY METAL CONCENTRATIONS IN SOILS OF BUMPUS COVE, TN." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/126.
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Mining processes generate waste rock, tailings, and slag that can increase heavy metal concentrations in soils. Un-reclaimed, abandoned mine sites are particularly prone to leaching these contaminants, which may accumulate and pose significant environmental and public health concerns. The characterization and spatial delineation of heavy metals of such soils is vital for risk assessment and soil reclamation. Bumpus Cove, once one of the richest mineralized districts of eastern TN, is home to at least 47 abandoned, un-reclaimed mines that were all permanently closed by the 1950s. This study evaluated 52 soil samples collected within a 0.67 km2 study area containing 6 known abandoned Pb, Zn, and Mn mines at the headwaters of Bumpus Cove Creek for heavy metal concentrations. Soil samples were analyzed for Zn, Mn, Pb, Cu, and Cd by means of microwave-assisted acid digestion and flame atomic absorption spectrometry (FAAS). Using the measured values and digital elevation model (DEM) derived from lidar data, ordinary kriging and cokriging interpolation techniques were used to predict the trend of heavy metal concentrations throughout the study area. Concentrations for Zn, Mn, and Pb show significant variability between sample sites (ranges of 12 – 1,354 mg/kg Zn, 6 – 2,574 mg/kg Mn, 33 – 2,271 mg/kg Pb). Cu and Cd were much less variable, with ranges of 1 - 65 mg/kg and 7 – 40 mg/kg, respectively. Of the measured heavy metals, only Zn and Pb exceed permissible limits in soils. Results show that ordinary kriging interpolation methods produced improved results over ordinary cokriging with and without lognormal transformations for all metals. Mn and Pb were found to transport further downhill following the natural drainage, whereas Zn, Cu and Cd concentrations exhibit localized variability without a clear transportation path. This study can provide a reference for state and local entities responsible for heavy metal monitoring in Bumpus Cove, TN.
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Bricker, Timothy J. "Metal removal from contaminated soil by hyper-accumulating plants : effects of repeated croppings." Virtual Press, 2000. http://liblink.bsu.edu/uhtbin/catkey/1172471.
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Phytoremediation, i.e., the use of plants to clean up contaminated soil, may serve as a feasible alternative if a high-biomass crop can be found that accumulates metals to a high.degree. Two plant species, corn (Zea mays) and Indian mustard (Brassica juncea), were grown in soil from a Superfund site contaminated with Pb and Cd (PbTota, = 65,200 mg/kg and CdTotI = 52 mglkg) over two croppings. Soil treatments consisted of composted sewage sludge (CSS), ethylenediaminetetraacetic acid (EDTA), and sodium citrate at two concentrations. In most cases, the EDTA and citrate treatments were superior in terms of extracting soil Pb into root tissue, and translocation of Pb into aboveground biomass. The CSS treatment typically resulted in the lowest Pb removal efficiencies. The high pH (7.4) and high exchange capacity of the CSS may have immobilized soil Pb. Soil Cd was generally more mobile than soil Pb. The EDTA2 treatment was most effective in removing soil Pb into roots, and translocation to shoots. Lead remaining in the soil after two croppings was mainly associated with the carbonate, organic, and residual fractions, which represent the less bioavailable form of this metal.Department of Natural Resources and Environmental Management
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Barajas-Aceves, Martha. "Soil microbial biomass and organic matter dynamics in metal-contaminated soils." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260604.
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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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Whitt, Michael John-Ross. "Studies to Characterize Heavy Metal Content and Migration From Recycled PolyethyleneTerephthalate." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1350.
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Packaging Materials account for 31% of the world’s municipal solid waste. Agencies like the Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) are pushing for the increased use of recycled thermoplastic materials. Polyethylene terephthalate (PET) is a commonly recycled thermoplastic which is used to package ready-to-eat fruits and vegetables. Most recycled polyethylene terephthalate (RPET) packaging materials contain heavy metal catalysts, the most common being antimony. The recent increased use of recycled plastic materials has been suspected as the source of increased human heavy metal exposure. In this study, cadmium, chromium, nickel, lead and antimony were quantified in post-consumer RPET rigid containers and films using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Two hundred samples were tested of which 29 were found to be contaminated with heavy metals in the parts-per-million (ppm) range. Chromium was found in all the contaminated sample replicates at an average level of 8.18 ppm. Cadmium was found in all the contaminated samples as well. Lead was found in 90.4% of the contaminated samples and concentrations ranged from a low of 0.02 ppm to a high of 0.36 ppm. Nickel was found in 96.4% of the contaminated samples while antimony was found in 97.6% of the samples. Due to limited sample material, 22 of the 29 contaminated RPET rigid containers and films were tested for heavy metal migration into a 5% citric acid:water solution (w/v) or deionized water. Samples were subjected to prolonged storage at 7.2 or 22.2°C for 1, 7 or 14 days, or were exposed for 5 minutes to microwaves from a 1700-watt microwave oven set to 70% power before analysis. Leachate values were at ppb levels but were often below the ICP-AES Limits of Detection which were at also the ppb level, whether calculated for deionized water or 5% citric acid in water. No measureable levels of heavy metal were detected for any sample exposed to water, regardless of treatment. For samples exposed to 5% citrate and stored or microwaved, only chromium and nickel leached at measurable levels, and the number of RPET’s releasing measurable chromium and nickel increased with microwaving compared to the same plastics stored at 22.2 or 7.2°C. Since leaching was calculated as µg/L of heavy metal lost from the entire inner surface (1021 cm2) of a retail salad bag, actual exposure to heavy metal would be much less than measured in this study as retail fruit and vegetable packages and microwaveable pouches usually contain very little liquid in order to increase food safety. The results therefore suggest the potential for little migration of heavy metal from recycled PET to whole or fresh-cut fruits and vegetables when held at ambient or refrigerated temperatures, or when microwaved.
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Van, der Waals Johan Hilgard. "Slags as agricultural limes : reactivity and heavy metal and phosphorus bio-availability." Diss., University of Pretoria, 2001. http://hdl.handle.net/2263/29056.
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Du, Wenzheng. "Movement of heavy metals and stability of metal-humic complexes in sludge-amended soil /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9901234.
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Soga, Benedictus Hope. "Regeneration of heavy metal contaminated soil leachate with chitosan flakes." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33844.
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Chemical treatment of contaminated soils (in-situ or ex-situ) is the current most practical option for remediation. The degree of metal complexation by organic acids depends on the type, concentration, metal type, pH and temperature. The influence of pH, temperature on the extraction efficiency of lead, zinc and copper was evaluated using Sodium citrate and sodium acetate buffers. Sodium citrate buffer was selected for the soil treatment. The soil was characterized for its pH, total metal content and the distribution of target heavy metals in soil fractions. Optimal conditions for Pb extraction with 0.5M citrate buffer was used to treat soil in batches and in columns, to evaluate their extraction efficiency and possible use for in-situ remediation.Chitosan, a derivative of chitin is a versatile biopolymer with metal uptake capabilities. Due to the large amounts of chitosan required to treat heavily contaminated leachates, magnesium (Mg) and iron (Fe) metals granules were evaluated for stripping the heavy metals from solution before the use of chitosan at optimized conditions to effectively polish the soil washing. (Abstract shortened by UMI.)
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Zhang, Weihua. "Chemical-enhanced washing for remediation of heavy metal- and petroleum hydrocarbon-contaminated soils /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202006%20ZHANGW.
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DEMUELENAERE, RAFAEL GERARD DE ALMEIDA. "CHARACTERIZATION OF HEAVY METAL TRANSPORT PROPERTIES IN RESIDUAL SOILS IN RIO DE JANEIRO." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5462@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOPROGRAMA DE APOIO A NÚCLEOS DE EXCELÊNCIA
A contaminação do meio ambiente de subsuperfície com resíduos perigosos e tóxicos tem se tornado um dos maiores problemas ambientais em vários países, com muitos locais apresentando contaminação da água subterrânea. A dissertação visa a caracterização de propriedades de transporte em solos residuais do estado do Rio de Janeiro; em especial será focalizado o comportamento e a mobilidade neste solo de metais pesados como o cádmio, zinco, cromo e chumbo. O conhecimento do comportamento dos metais no solo é importante para a previsão de acidentes ambientais e para a avaliação de possíveis soluções. Mudanças no ambiente, como variação do pH, podem interferir no comportamento do metal, desta forma o conhecimento das condições locais é importante para previsão do comportamento do contaminante. Foram realizados ensaios de batelada e de coluna com diferentes metais, para entender como se comportam nos solos residuais caracterizados. Para complementar o estudo uma modelagem geoquímica foi feita a partir dos dados experimentais com o programa computacional PHREEQC.
The contamination of the underground environment by hazardous and toxic wastes has become one of the main environment problems in several countries where many sites present groundwater infection. The project purpose is the characterization of the transport properties in residual soils of the Rio de Janeiro state. Mainly it will be focused the behaviour and the mobility of heavy metals, for example, the cadmium, the zinc, the chromium and the lead in this kind of soil. To know the behaviour of the metals in the soil is important for the prevision of environmental accidents and for the evaluation of possible solutions. Changes in the environment, as the pH variation, may interfere in the metal conduct thus the knowledge of the local conditions is essential for the prevision of the contamination procedure. Batch and column tests were made using different metals in order to understand how they act in the characterized residual soils. To complement the studies a geochemical modeling was made using the experimental data with the compute program, PHREEQC.
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Sallami, K. "The phytoremediation of heavy metal contaminated roadside soils in Libya by Eucalyptus camaldeulensis." Thesis, Coventry University, 2015. http://curve.coventry.ac.uk/open/items/163dce75-3b00-41d6-a1b8-5c9cbb896a39/1.
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There is a public concern over the potential accumulation of heavy metals in soils. Numerous studies have already demonstrated that areas in close proximity to vehicular traffic are marked noticeably by contamination of soil, air and water. Hence, such activities can affect humans and other living organisms. The aim of this study is to investigate the pollution of soils caused by vehicular traffic, on agricultural land in Azzawiyah, Liby with the view of assessing potential application of phytoremediation options for the remediation of contaminated soils and determine whether soil amendments would improve soil remediation. In an effort to improve the status of pollution of soils by vehicular traffic, a phytoremediation method of remediation of contaminated land has been used in this study, as it is relatively inexpensive and has the potential through the appropriate selection of plant species to be effective. This method is a soil clean up technology that uses the ability of metal accumulator plants to extract metal from contaminated soil with their roots and to concentrate these metals in above-ground plant parts. In this study, the investigation area was in Azzawiyah city where the soil samples and Doedonea viscose plant were collected from the road side. These soil samples were analysed using different experiments to determine physical and chemical properties, such as pH, OM and CEC. Heavy metals in soil and Doedonea viscose shoot and root were analysed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The findings of the study show that all soils samples collected along the highway road connecting Azzawiyah with the southern parts of Libya were found to be granular with a sandy texture. It is also found that the metal content in soil collected from the site, which is close to the roadside was relatively higher than that soil collected from the agricultural field in the same area. Furthermore, the level of Pb (840mg/kg-1) in roadside soils was higher than the natural levels of Pb in soils. In addition, Doedonea viscose plant was not a hyperaccumulor plant. Greenhouse experiments used three plants (E. camaldeulensis, Brassica Juncea and Medicago sativum) to uptake heavy metal, such as Cd, Zn and Pb from the soil samples. The greenhouse experiment results indicate that E. camaldeulensis was the best plant species for phytoremediation of Pb contaminated soils than the other two plants species (Brassica Juncea, Medicago sativum). The efficiency of the E. camaldeulensis was increased by adding amendments (e.g. compost, compost, EDTA, Hoagland solution and Alcaligenes eutrophus) to the plants pots in order to uptake the lead form soil samples. The results of the pots amendments experiments indicate that 15 mmol of EDTA and bacterial inoculums (Alcaligenes eutrophus) were the best amendments to extract lead from the soils. The study suggests that using the Alcaligenes eutrophus with the E. camaldeulensis are more suitable for phytoremediation in terms of accumulation and cost.
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Brim, Hassan. "Molecular approaches to study bacterial strains and communities of heavy metal polluted soils." Doctoral thesis, Universite Libre de Bruxelles, 1997. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212200.
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Mgobozi, Vuyokazi. "Heavy metal content absorption and medicinal potential of Egeria densa (Planch.) Casp." Thesis, University of Fort Hare, 2013. http://hdl.handle.net/10353/d1013121.
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The contamination of heavy metals in the environment is a looming concern worldwide. Egeria densa (Planch) (Submerged aquatic plant) from two ponds: Site A with co-ordinates (32º 48’22.04”S; 26°48’58.79” E) and Site B with co-ordinates (32°48’33.25”S; 26°48’33.25”S) in Alice (Eastern Cape) was evaluated for its ability to absorb heavy metals, phytochemical constituents, antimicrobial activity and ultra-structure using standard analytic procedures. Cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), and zinc (Zn) were measured in water, sediments and plant. The concentrations of these metal elements were determined with use of Inductively Coupled Plasma- Optical Emission Spectrometry (ICP-OES). In sediments, the heavy metals (mg/kg) decreased in the order of their average concentration as follows: Fe (40.320) > Zn (1.259) > Pb (0.564) > Mn (0.186) > Cu (0.037) in Pond 1 whereas in Pond 2 Fe (61.527) > Cd (0.999) > Mn (0.648) > Pb (0.586) > Zn (0.156) > Cu (0.045). The highest concentration of Fe was detected in both sites and Cu being the least. The concentrations of the metals in the plants sample (from Pond 1) were found in order of Mn > Pb > Cu > Fe whereas cadmium and zinc were not detected, while the concentration in Pond 2 decreases in order of Zn > Mn > Pb > Cd > Fe > Cu. In the water samples, concentrations of heavy metals (mg/L) decreased in the order of their average concentrations as follows: Pb (35.36) > Fe (3.07) > Mn (0.238) > Cu (0.104), both cadmium and zinc were below the limit of detection in Pond 1, whereas in Pond 2 the concentrations decreased as follows: Pb (13.033) >Fe (1.69) > Cu (0.270) > Mn (0.248) > Cd (0.004) and Zinc was not detected. Phytochemical analyses of the plant extracts revealed the presence of phenols, flavonoids, proanthocyanidin, flavonols, saponins, alkaloid and tannins in all the extracts (water, acetone and n-hexane). Both acetone and water extracts, showed high concentration of proanthocyanidin, while tannin was the lowest in acetone extract. Antimicrobial evaluation using, Gram positive (Staphylococcus aureus, Bacillus pumilus, Bacillus cereus, Streptococcus pyogenes, Enterococcus faecalis) and Gram negative (Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris and Serratia marcescens) bacteria showed negative results for all the strain, except Streptococcus pyogenes which was inhibited at MIC of 0.1 mg/ml. Scanning electron microscopy (SEM) of ultra-structure of Egeria densa, showed that certain bacteria attached to the leaf, However more work has to be done on E. densa to verify the mechanism by which it accumulates heavy metals. The study shows that E. densa has a potential of accumulating heavy metals especial Manganese in plant.
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Lander, Mark S. "Evaluation of selected heavy metal concentrations in soils of an urban stormwater retention basin." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0002831.
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Pronoza, Lesya. "Phytoremediation of heavy metal polluted soils in marginalised regions: opportunities, limitations and sustainable development." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-33122.
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Soil pollution is one of the problems that obstruct sustainable development in the affected regions, posing a threat to the local environment, ecosystems and human wellbeing. Phytoremediation is one of the techniques used to clean polluted soils. It relies on the ability of some plants to absorb or stabilize certain substances from soil, including organic and inorganic pollutants. Amaranth was chosen as a potential candidate for the proposed phytoremediation project in Chinandega region, Nicaragua, an area that was heavily used for cotton production in the last century, and is now characterised as having high levels of soil pollution, Cd being one of the most common one. The aspects such as opportunities and limitations for the designing of such a project, as well as its contribution to the sustainable development of the region were examined in this thesis. To further support the investigation, the laboratory experiment was performed to study the uptake rate of Cd by amaranth in a greenhouse conditions. The results of the study show that the main opportunities for the design of this project would be the possibility of combining the cleaning of soil with co-benefits such as producing food and energy, as well as additional removal of organic pollutants. The main limitations would be the lack of initial data about the pollution, and possible economic losses due to inability of using amaranth for food. The implementation of this project in real life would mean a support of sustainable development of the Chinandega region on many levels, including social, environmental and economic benefits. The results of the laboratory pot experiment are yet to be included in the study, as the experiment still continues.2017-10-30
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Steele, Mark. "Ex-situ remediation of a metal-contaminated superfund soil using selective extractants." Virtual Press, 1997. http://liblink.bsu.edu/uhtbin/catkey/1048379.
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Extractive processes can permanently and significantly reduce the volume, toxicity and mobility of contaminated materials at affected sites. Ethylenediaminetetraacetic acid (EDTA), N-2 (acetamido)iminodiacetic acid (ADA), pyridine2,6-dicarboxylic acid (PDA), and hydrochloric acid (HC1) were evaluated in batch studies for their ability to remove lead (Pb) and cadmium (Cd) from a Superfund soil. The extraction of Pb as a function of time was limited and the order of Pb removal was EDTA > ADA > PDA > HC1. Repeated extractions did not treat the soil below the Pb regulatory limit (1,000 mg/kg); however, the Pb remaining occurs in an immobile form. All extractants treated the soil below the proposed Cd regulatory limit (40 mg/kg) within 1 h. Lead recovery from solution was accomplished by hydroxide precipitation in the presence of excess calcium, and recovery at pH 11 was 70%, 98%, and 97% from the EDTA, ADA, and PDA complexes, respectively.Department of Natural Resources and Environmental Management
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Pham, Vivian G. "Ecological Risk Assessment of Heavy Metal Content in the Hatillo River, Costa Rica." Scholarship @ Claremont, 2015. http://scholarship.claremont.edu/scripps_theses/571.
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Rivers all around the world have become increasingly polluted with heavy metals, largely due to industrialization and urbanization. Organisms exposed to high concentrations of heavy metals have shown evidence of biotoxicity and physical deformities. With biomagnification in mind, the possibility that this contamination may soon directly affect humans is a real concern, and policies in manufacturing industries worldwide may have to be reformed. In this study, we measured the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb) in the Hatillo River and compared these values to those measured in the Tarcoles River, a highly polluted river, and Terciopelo Creek, a relatively clean river. The results showed that the Hatillo River had significantly lower levels of most detected heavy metals than both the Tarcoles and Terciopelo. Overall, sediments in all rivers showed high levels of heavy metal content--especially in chromium, copper, nickel, and lead--which could build up and affect organisms over a long period of time.
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Allen, Tammy Reneé. "A classification of the dress of heavy metal music groups using content analysis /." This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12042009-020120/.
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Allen, Tammy Rene. "A classification of the dress of heavy metal music groups using content analysis." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/46090.
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The research was a qualitative study of the dress of heavy metal (HM) music groups using content analysis. The purpose was to examine dress characteristics of a representative random sample of HM music groups. The objectives were (a) to develop a classification system for HM music groups based on time and subgenre, (b) to identify music groups within each cell (i.e., time and subgenre) of the classification system, and (c) to identify dress characteristics of a representative random sample of the music groups.
The subjects in the study were HM music groups as pictured on albums. The variables were the selected items of dress and the classification of the groups by time and subgenre. A classification system was developed and used for the selection of subjects. Using the HM Dress Classification Instrument developed by the researcher, specific dress characteristics of twenty-four HM music groups were identified. This data was compiled in tabular format.
Among the twenty-four HM groups, the predominant clothing was a black woven shirt and black leather/suede pants. Clothing trim included studs, motifs/designs, words and fringe. No visible jewelry was predominant. The primary shoes observed were western boots. Straight, shoulder-length black or blond hair with no head covering was predominant. Beards, makeup, tattooing, and other forms of corporal adornment were observed. Although some dress categories were dominated by single items, changes were observed across time and subgenres. The data indicated rejection of the two null hypotheses.
Master of Science