Dissertations / Theses: 'Toxicity of copper in worms'

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Charmley, L. L. "Copper metabolism and toxicity in cattle and pigs." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370118.

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Barrow, Linda. "Copper hepatotoxicity and transport." Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/35207.

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Indian Childhood Cirrhosis (ICC) is associated with excessive copper ingestion and hepatic deposition, is preventable by preventing copper ingestion and is partially treatable by copper chelation. However, copper administration causes only minimal hepatic damage in the rat and an acute rather than chronic liver injury in sheep. The hypothesis is explored that a second hepatic insult is synergistic with copper in causing cirrhosis. D-galactosamine was administered, to control rats and to rats orally dosed with copper acetate, to induce an acute hepatic injury documented by serum transaminases and liver histology. Surprisingly, copper-dosed rats (liver copper 607+129 ug/g, controls 48+7) were resistant to galactosamine-induced injury. Oral copper reduced the quantitative faecal anaerobical1y cultured bacterial count, suggesting that reduction in gut-derived portal vein endotoxin may explain the protective effect. Using the carbon tetrachloride model, copper again ameliorated, rather than aggravated, the hepatic injury. Impaired prostaglandin or leukotriene synthesis are discussed as possible mechanisms. To evaluate a possible disorder of copper transport in ICC, copper distribution amongst human serum proteins was investigated. In normal adults, copper was associated with caeruloplasmin (71+4%), "transcuprein" (7+2%), albumin (19+4%) and with amino acids (2+3%). Caeruloplasmin and caeruloplasmin-copper concentrations were low in neonates and symptomatic Wilson's disease. In contrast to the neonate, Wilson's disease exhibited raised total serum copper and non-caeruloplasmin-copper. In ICC, serum levels of caeruloplasmin and caeruloplasmin-copper were normal, but transcuprein- and albumin-bound copper were elevated. Raised concentrations of non-caeruloplasmin-copper in ICC and Wilson's disease perhaps represent overspill into the serum from a copper-laden liver. In serum from children with malignancy, copper and caeruloplasmin concentrations were high as previously reported. Unexpectedly transcuprein- and albumin-bound copper were also markedly elevated. It is to be determined whether this results from tissue catabolism of caeruloplasmin or from increased hepatic caeruloplasmin synthesis and copper turnover. Caeruloplasmin gene expression was investigated in adult and neonatal rat liver, to determine whether the copper profile seen in neonates results from a pre-translational defect in caeruloplasmin synthesis. Detection of mRNA in samples of Northern blotted polyadenylated RNA, using a 32P-labelled caeruloplasmin cDNA probe, demonstrated that the mRNA species isolated from the neonates was not different from that in the adults, with an apparent size of 4400 nucleotides. A reduced mRNA detection in neonatal rats was also shown. Whether this was sufficient to account for the diminished total serum copper and caeruloplasmin oxidase activity is not understood.

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Dincer, Zuhal. "Copper toxicity in sheep : studies on copper chelation by ammonium tetrathiomolybdate (TTM) and metallothionein." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241482.

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Blanchard, Jonathan. "Copper Toxicity and Accumulation: Physiology, Chemistry, and Molecular Biology." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/284.

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Our knowledge of aquatic Cu toxicity has increased greatly over the past several years culminating with the incorporation of a model (the Biotic Ligand Model (BLM)) into the regulatory framework which allows for the site specific adjustment of water quality criteria based on water chemistry. However, our understanding of Cu toxicity in the aquatic environment is limited mostly to freshwater (FW). Because of this limited knowledge, this dissertation set out to examine the affect of salinity on Cu toxicity and accumulation across salinities from FW to sea water (SW). First, this work examined tissue specific Cu accumulation in five salinities (FW, 5 ppt, 11 ppt, 20 ppt, 28 ppt) from waterborne Cu exposure at two [Cu] (30 and 150 µg Cu L-1) in the euryhaline killifish, Fundulus heteroclitus. Branchial and hepatic accumulation followed a pattern that would be expected based on speciation and competition from cations. [Cu] were high in FW and decreased as salinity increased. However, in the intestine, [Cu] were highest at 5 ppt and were also elevated in the higher salinities. The elevation at the higher salinities was most likely due to drinking by the fish which increases as salinity increases above the isoosmotic point of the fish (~10 ppt) for osmoregulatory purposes and showed a trend toward increasing [Cu] with increasing salinity as would be expected. Secondly, the mechanism of Cu toxicity in FW and SW was examined in killifish. The mechanism of Cu toxicity in the killifish in FW was the same as had been seen for other FW fish. Cu exposure caused a decrease in Na+ / K+ ATPase activity which led to a decrease in whole body [Na+] which is the likely cause of death. In SW, surprisingly no ionoregulatory disturbances were observed. The only measured parameter that was changed in SW was net ammonia which showed a substantial decrease. Therefore, the mechanism of acute copper toxicity in FW and SW differed suggesting that physiology may need to be considered in future development of a BLM for SW. Next, the effect of salinity on Cu accumulation from a naturally incorporated dietary source was examined in FW and SW in Fundulus heteroclitus. Cu accumulation was not seen to differ in the two salinities in spite of differences in gut fluid chemistry that would lead to an ~11 fold difference in free Cu ion between FW and SW. This indicated that Cu accumulation from a dietary source was not as the free ion but most likely as organically (amino acid) bound Cu. In addition to this, subcellular fractionation of the diet revealed that Cu available to the next trophic level did not change with increasing waterborne [Cu], increasing tissue [Cu], or time in oysters which has implications for Cu accumulation in the environment. Finally, the molecular mechanisms behind effects and acclimation to waterborne and dietary Cu exposure in FW and SW were examined using suppression subtraction hybridization in the killifish intestine. Exposure to Cu induced a stress response which could be responsible for upregulation of genes involved in protein synthesis, proteolysis and ATP production. At the tissue level, two main responses were observed. First, genes necessary for muscle function were upregulated potentially in response to previously observed decreased intestinal motility. Secondly, apoptotic genes were upregulated corresponding to increased rates of apoptosis in intestines during dietary exposures. At the cellular level, metal chelators and oxidative stress genes were upregulated in response to increased free Cu in the cell and the subsequent free metal induce free radical formation. This work has advanced our understanding of Cu toxicology in saline environments and emphasized the importance of considering both chemistry and physiology in analyzing and interpreting Cu toxicology especially in saline environments. Hopefully, it will contribute to the future development of Cu water quality criteria.

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Schweigert, Nina Anke. "Modes of action and toxicity of (chloro-)catechol/copper combinations /." Zürich, 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13353.

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LaBreche, Timothy Merrick Clark. "Toxicity of Copper to Mercenaria mercenaria (Hard Clam)." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/46181.

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Toxicity of copper to larval Mercenaria mercenaria was evaluated with static non-renewal and continuous renewal methods that permitted daily observation of mortality, activity, development, and metamorphosis without subsampling. Clam larvae, 100 - 150 microns, were held for up to two weeks in small, 30 mm, sealed petri plates during static assays with excellent survival of control organisms, low evaporative losses, and relatively low between replicate variability. An eight day LC50 of 12 micrograms / liter for six day old organisms was determined as well as EC50s (active swimming). EC50s at 24 hours were as much as much as seven times lower than LC50s after 24 hours of exposure. Flow - through assays were conducted with a modified petri dish design. Two sections from opposing sides of a 30 mm petri dish were removed and covered with 35 micron polyester screening. This dish (organism dish) was placed in an outer catch dish that captured the effluent toxin as it passed through the screening and routed it to a catch bottle for water quality analysis. The toxicant feed line entered through the catch dish cover and slowly dripped toxin into the organism dish. Water quality in the flow - through assay remained excellent. Survival of control organisms in the flow - through assay was lower than in static assays, but metamorphosis was not delayed as had been observed in static assays. Data variability was low enough that statistical distinctions were made between the effects of copper on metamorphosis. A non-standard "M" shaped survival response was observed in all assays. The responses generating the "M" shaped response in the static petri assay were statistically different from each other. Activity, as judged by swimming, in organisms was not observed to follow the "M" shaped pattern. Instead, it decreased exponentially with increasing copper concentrations. Static experiments with unfed clams, observations of activity, and data from experiments in copper accumulation by algae led to a theory relating the unusual dose response to food consumption and its relationship to the effective dose of copper to which the larval clams were exposed. Master of Science

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Flora, Christopher S. "The Silicon-Mediated Alleviation of Copper Toxicity in Nicotiana tabacum." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1537286692916071.

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Fuentealba, I. C. "Cellular mechanisms of toxicity and tolerance in the copper-loaded rat." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383477.

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Nielsen, Hanne Dalsgaard. "Copper toxicity in the physiology and early development of Fucus serratus." Thesis, University of Plymouth, 2002. http://hdl.handle.net/10026.1/502.

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Sirois, David J. "Theoretical copper sulfate dosing: the effect of alkalinity and humic acid on ionic copper toxicity to algae /." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-03022010-020227/.

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O'Reilly, Kirk Thomas. "The role of copper in the apparent aluminum toxicity of aquatic systems." PDXScholar, 1985. https://pdxscholar.library.pdx.edu/open_access_etds/3522.

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The effect of variations in aluminum and copper concentrations on the growth rate and enzyme activity of the green alga Scenedesmus quadricauda was investigated. The goal was to determine which chemical species control the biological parameters. The computer program MINEQL (Westal et al 1976) was used to estimate chemical speciation. In the prevalence of both metals, algal growth rate and alkaline phosphatase activity could be correlated to cupric ion activity. The activity of isolated bacterial alkaline phosphatase was found to be a function of both total copper concentration and cupric ion activity. A model was developed to predicted the effects on alkaline phosphatase of perturbation in aquatic chemistry.

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Payne, Chris 1971. "Phylogenetic trends in phytoplankton resistance to Cd and Cu toxicity." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24033.

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Some species of marine phytoplankton are believed to be more tolerant of high concentrations of trace metals than others, but no conclusive test of this hypothesis has been conducted. Eleven species of phytoplankton representing 5 classes were grown in Aquil medium containing Cd$ sp{2+}$ concentrations between 10$ sp{-9.85}$ and 10$ sp{-6.84}$ M. Growth rates and intracellular concentrations of Cd, C, N and S were measured. Cadmium quotas (mol Cd/litre-cell volume) were lower in members of Bacillariophyceae than in Chlorophyceae, Prymnesiophyceae, Dinophyceae and Cyanophyceae (ANOVA, p $<$ 0.001). Cellular C:S molar ratios decreased in phytoplankton grown at high (pCd 7.37-6.84) compared to low Cd (no added Cd), as S/litre-cell volume increased. Similar results were observed for C:N molar ratios. In two species that were examined, C:S ratios decreased as a linear function of increasing Cd concentration. Mean Cd$ sp{2+}$ concentration that reduced growth rate to 50% of maximum (pCd$ sp{50})$ was not significantly different among phytoplankton classes (ANOVA, p $<$ 0.05). When these experimental data were combined with pCd$ sp{50}$s calculated from published sources, Chlorophyceae were found to be the most resistant class (ANOVA, p $<$ 0.01). Cadmium and Cu resistance (pCd$ sp{50}$ and pCu$ sp{50})$ were correlated (r = 0.52, p $<$ 0.05), suggesting co-tolerance of phytoplankton to toxic levels of these metals. Chlorophyceae were most tolerant and Cyanophyceae the least tolerant of Cu (ANOVA, p $<$ 0.01). No significant differences were observed among Bacillariophyceae, Prymnesiophyceae, and Dinophyceae, which were of intermediate sensitivity to both metals. The results confirm the existence of a phylogenetic dependence of resistance to trace metal toxicity in phytoplankton.

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Woodall, Christopher John. "Cadmium, zinc and copper regulation involving metallothionein gene expression in the Anuran X. laevis." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328602.

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Arnegard, Matthew E. "Toxicant-releasing substrates : a new method for delivering copper to microbial communities in SITU /." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12162009-020200/.

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Garnacho, Eva. "Ecotoxicology and ecophysiology of mysids, with special reference to copper toxicity in Praunus flexuosus." Thesis, University of Southampton, 2000. https://eprints.soton.ac.uk/42089/.

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Toxicity of dissolved copper was examined in a common coastal mysid population {Praunusflexuosus). The life cycle and ecophysiology were studied under natural conditions throughout the year, and responses to dissolved copper were determined in the laboratory. Pronounced and ontogenic seasonal differences in copper toxicity for the mysid Praunus flexuosus were observed. Sublethal and lethal parameters (mortality, behaviour, metabolism, reproduction, and bioaccumulation) showed seasonal variation in response to copper toxicity, being highest toxicity in summer. Changes in the form of dissolved copper were measured during toxicity testing, using the chelating resin method to provide a measurement oftotal and labile (Chelex-available) dissolved copper in the natural seawater used in the toxicity tests. Labile dissolved copper did not show significant variations in the test seawater, confirming that organisms were exposed to constant labile copper concentrations during the toxicity test. The total dissolved copper concentration was significantly higher than the labile form, as organic complexation occurred in natural seawater and during toxicity tests. The labile fraction could be less than 50% ofthe total fraction. The total dissolved copper concentration decreased significantly when the organism was under stress. While the mortality of the population was insignificant after 10 days of copper exposure (0, 5,25, 75 and 200g 1"') in winter, lethal effects occurred at every copper exposure level after 24 hours (96h LC50 =30.8 g 1"') in summer. The effects of copper on metabolism (respiration and excretion) were very sensitive indicators of sublethal toxicity, which resulted in lethal effects with a prolonged time of exposure. Metabolism shifted to a greater reliance on protein catabolism under copper exposure in both seasons, demonstrating a stronger effect in summer. Total copper content accumulated in the organism increased with increasing copper concentration in solution. Copper accumulation rate was higher in summer . than in winter, increasing to rates of7^g g*1 dry weight day"1. Reproductive processes were severely disrupted at any copper treatment. Production ofjuveniles was reduced to zero, because of the high abortion rate, reduction on brood survival and damage to fertilisation processes.

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Blake, Deanne Renee. "Effects of Layer Double Hydroxide Nanoclays on the Toxicity of Copper to Daphnia Magna." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115048/.

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Nanoparticles may affect secondary pollutants such as copper. Layer Double Hydroxides (LDH) are synthetically produced nanoparticles that adsorb copper via cation exchange. Pretreatment of copper test solutions with LDH nanoparticles followed by filtration removal of LDH nanoparticles demonstrated the smallest LDH aggregates removed the most copper toxicity. This was due to increased surface area for cation exchange relative to larger particle aggregates. Co-exposure tests of copper chloride and clay were run to determine if smaller clay particles increased copper uptake by D. magna. Coexposure treatments had lower LC50 values compared to the filtration tests, likely as a result of additive toxicity. LDH nanoclays do reduce copper toxicity in Daphnia magna and may serve as a remediation tool.

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Mohammadbakir, Sahib. "Impacts of waterborne copper and silver on the early life stage (ELS) of zebrafish (Danio rerio) : physiological, biochemical and molecular responses." Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/6550.

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Toxic metals are major pollutants of the aquatic environment and are able to cause survival impairment of the early life stage of the aquatic organisms. They can affect the osmoregulatory system and electrolyte balance in fishes as well as the expression of genes which are essential in the formation and development of the organs at the early embryonic stages of development. There are a lack of studies concerning the toxic effects of waterborne copper and silver on the osmoregulation, electrolytes balance and expression the genes which are responsible for the formation and development of heart and metal binding proteins in the early life stage of zebrafish. The current study aimed to assess the toxic effects of waterborne concentrations of copper as an essential trace element, and silver as a non-essential trace element, on biochemical processes and the molecular biology of the early life stages (ELS) of zebrafish. The first experiment of the current study (Chapter 3) aimed: 1. to determine the time of nkx2.5 gene expression, a gene involved in cardiac development, relative to the time of embryonic development. 2. To assess the toxic concentration of the copper and most vulnerable and sensitive stage of the embryos < 1 hour post fertilization (hpf) exposed to the copper via water route. The result of the experiment showed that the expression of the nkx2.5 gene reached a maximum at 16 hpf. The first 10 hpf of the embryonic development was the most vulnerable and critical stage of the developing embryos, and characterized by increased mortality as copper concentration increased, and delayed and decreased hatching success. Exposure of embryos for 72 hpf to a concentration of 500 µg L-1 Cu increased heart rate, whereas the exposure of the embryos at the blastula stage only, showed decreases in heart rate. The third part of the experiment evaluated the protective effect of calcium as a major cation of water hardness on Cu toxicity. Embryos age < 2 hpf were exposed to copper (0, 100, 250, and 500 µg L-1), with or without added calcium (40 mg L-1). An increase in embryonic Cu accumulation was observed in live and dead embryos exposed to Cu, with and without added calcium. Calcium concentration increased with embryonic copper tissue concentration in dead embryos. Na+ and K+ concentrations were higher in live embryos compared to dead embryos, and a 4 fold decrease in Na+K+-ATPase activity was seen in live embryos exposed to copper compared to controls. There was no effect of copper on total glutathione. Expression of nkx2.5 as one of the essential genes for the formation and development of the heart increased significantly; approximately 10 fold in the presence of Cu+Ca in comparison to the unexposed control or Cu exposure alone. Whereas expression of mt2 increased significantly 6 fold compared to the control during Cu exposure without added Ca2+. The second experiment (Chapter 4) aimed to investigate the effect of the dissolved Ag+ as AgNO3 on the survival of the early life stage of zebrafish. Embryos < 2 hpf were exposed to silver 0 (no added Ag), 2.5, 5, 7.5, 10 and 15 µg L-1 Ag as AgNO3 for up to 72 h. Although, the survival was not affected by increasing concentrations of total silver, a decrease in hatching and increase in heart beat was observed. A significant increase in embryonic silver accumulation in both live embryos (at 24 and 72 hpf) and dead embryos (at 24 hpf) was observed. The accumulation of silver in 24 hpf live embryos was more significant than in dead embryos. Dead and live embryos at 72 hpf exposed to Ag had lower Na+ and K+ concentrations. Live embryos also showed a transient increase in Ca2+ concentration at 24 h. Four fold increases in Na+K+-ATPase activity, Mt2, and total glutathione concentration were seen in embryos after 72 h of exposure to AgNO3 compared to controls. In contrast, nkx2.5 gene expression was significantly decreased by 3 fold in 24 h aged embryos exposed to silver compared to controls. Due to the lack of studies that investigate the effect of silver on protein expression profiles during the early stages of development of zebrafish, the third experiment (Chapter 5) aimed to investigate the effect of silver on the changes of the expressed proteins of zebrafish embryos at the segmentation stage (24 hpf). The proteomics analysis successfully identified total of 810 proteins in the embryonic homogenate and quantified changes in their abundance in response to silver exposure. MS analysis showed the induction of new proteins which were absent in control embryonic homogenates. Also the analysis revealed there were increased expression of proteins such as zona pellucida glycoprotein, ATP synthase subunit α and β, stressed proteins such as metal chaperones and heat shock proteins, antioxidant proteins such as catalase (CAT), superoxide dismutase (Cu-Zn), glutathione S-transferase M, and glutathione S-transferase and proteins related to muscular development such as myosin heavy polypeptide 2, actin alpha 1 skeletal muscle, slow myosin heavy chain 1, actin cytoplasmic 1, and tropomyosin proteins. Overall, the thesis confirmed that the early life stages of zebrafish are sensitive to metals and that there are critical windows of toxicity during development. Metal exposure at early stages of the development initiate several disturbances in biochemical processes as well as changes in molecular biology that affect fish survival.

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Gamez, Grijalva Victor Manuel. "BIOLOGICAL AND PHYSICAL-CHEMICAL METHODS FOR TREATMENT OF SEMICONDUCTOR MANUFACTURING EFFLUENTS." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195838.

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Semiconductor manufacturing is one of the most advancing, growing and evolving industries. The production of semiconductors presents several challenges, both technologically and environmentally. The amount and complexity of the chemical substances utilized in the manufacturing process has been growing exponentially, and new chemicals are often introduced to the process and the environment. Two steps of this process play a special important role in the introduction of new chemical and demand of natural resources: Chemical Mechanical Planarization (CMP) and Photolithography.Wastewaters from the semiconductor manufacturing are complex and have several chemicals in different concentrations. Heavy metals, acids, chelators, surfactants and other chemicals are found in semiconductor effluents. Part of the scope of this study is to evaluate and remediate wastewaters produced in semiconductor manufacturing.During the development of this project it was found that copper can be successfully removed and recovered from CMP wastewaters by the use of a sulfate reducing bioreactor and a crystallization reactor, promoting precipitation of copper sulfides on the surface of silica sand. High removal and recovery efficiencies were found as result of the study. Another finding include that citrate is a readily biodegradable compound which can be successfully utilized as electron donor for anaerobic processes such as methanogenesis and sulfate reductions. However other important chelator, like EDTA, can cause toxicity to these microorganisms and affect important biological processes. PFOS is an important chemical for the semiconductor industry; however, the physical and chemical properties make this compound persistent in the environment and bioaccumulative. New substitutes for PFOS were tested and evaluated for their environmental impact. It was found that perfluorination plays an important role in the chemical properties of PFOS and removal of this characteristic improves the environmental performance of the new substitutes. Evaluation of these new chemicals was also performed by simulation and modeling. The software utilized in this study identified properties like toxicity and octanol-water partition coefficient accurately. On the other hand biodegradability was poorly estimated and new models are suggested for evaluation of this property for compounds with characteristics similar to the ones studied here (specifically high fluorination).

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Abdul, Rahim Khairuddin bin. "Interactions of arbuscular mycorrhizal symbionts with arsenic and other potentially toxic elements." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326752.

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Hanvey, W. C. "The influence of chemical speciation of copper and cadmium on toxicity in Gammarus duebeni, Asellus aquaticus, and Baetis spp." Thesis, University of Ulster, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356450.

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De, Vizcaya Ruiz Andrea M. G. "Distribution, toxicity and mode of action of the novel copper-based anticancer compound, casiopeina II." Thesis, University of Surrey, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310720.

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Sarell, Claire Jessica. "The copper-amyloid-beta-peptide complex of Alzheimer's disease : affinity, structure, fibril formation and toxicity." Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1293.

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Senile plaques of Alzheimer’s disease (AD) patients are composed primarily of the amyloid-β-peptide peptide (Aβ), and within these plaques Cu2+ ions are found concentrated and directly bound to Aβ. Cu2+ homeostasis is severely impaired in AD patients and recent in vivo studies implicate Cu2+ in the etiology of AD. However the role of Cu2+ ions in AD is currently highly disputed due to the low reported affinity of Aβ for Cu2+ (nM and μM), and Cu2+ binding to Aβ is thought to result in amorphous aggregation rather than fibril formation. These two aspects, along with the coordination geometry, stoichiometry and toxicity of the Cu2+-Aβ complex were investigated in this thesis. In Chapter 3, circular dichroism and fluorescence spectroscopy alongside competitive metal capture show a surprisingly high picomolar affinity for both monomeric and fibrillar Aβ. In Chapter 4 electron paramagnetic resonance was used to study the structure and stoichiometry of the copper-Aβ complex in both monomeric and fibrillar Aβ. Both Aβ forms were able to bind a full stoichiometric complement of Cu2+ ions, with identical square planar coordination geometry. Importantly Cu2+ ion binding did not disrupt fibril structure. In Chapter 5 of this thesis it is shown that, in contrast to the predominant belief in the AD field, stoichiometric and sub-stoichiometric amounts of Cu2+ actually accelerate the rate of fibril formation. Finally, the toxic effects of Aβ and Cu2+ were studied in a PC12 clonal cell line. The presence of Cu2+ ions were found to enhance Aβ cell toxicity, and substoichiometric concentrations of Cu2+ were found to be the most toxic, suggesting that Cu2+ induced fibril formation and Cu2+ induced toxicity may be linked. Therefore this study finds considerable support for an altered amyloid hypothesis where Cu2+ dyshomeostasis has a central role in AD.

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Campbell, Melissa N. "Effects of Predatory Cues on Copper Sensitivity and Metabolic Rate in Gambusia affinis." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etd/3250.

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Organisms living in aquatic environments are subject to a number of stressors from natural (temperature, predation, food availability) and anthropogenic origins (pesticides, metals, etc). Natural stressors may amplify the effects of contaminants and increase an organism’s sensitivity to them. Understanding the impact of these combined factors is therefore essential for the practical management of contaminants. This study sought to examine how predatory cues affect copper tolerance in the mosquitofish, Gambusia affinis. The influence of predatory cues on fish metabolic rate was also evaluated to gain insight on any interactive effects between the natural stressor and copper. Alarm cues, chemicals released into the water when prey are injured were obtained from humanely sacrificed G. affinis, and kairomones, passive cues released by predators, were obtained from adult bluegill (Lepomis macrochirus). Paired 96-h toxicity tests with copper and predatory cue and with copper alone were conducted to determine the influence of predatory cues on G. affinis sensitivity to the metal. In the presence of alarm cue neither G. affinis copper tolerance or metabolic rate was altered. At copper concentrations ranging from 0.25mg Cu/L - 0.50mg Cu/L kairomone presence had no influence on survival, while between 0.50mg Cu/L and 1.0mg Cu/L, kairomone presence increased survival. Kairomone had no significant effect on metabolic rate. The apparent antagonistic effect between kairomone and copper may have resulted from the presence of organic material from predator-derived cues or from potential changes in fish behavior. This study adds to the growing body of literature which illustrates the complexity of stressor interactions in aquatic systems.

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Bradley, Matthew Darren. "The accumulation and toxicity of copper, zinc and manganese in the farmed snail Helix aspersa maxima." Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307215.

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Wong, Nga Cheung. "Effects of algae (Isochrysis galbana) and humic acids on copper toxicity to polychaete (Hydroides elegans) larvae." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/665.

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Simpson, Melinda Mallory. "USE OF COPPER SULFATE TO CONTROL HAEMONCHUS CONTORTUS INFESTATION IN HAMPSHIRE EWES." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/135.

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Two studies were conducted to evaluate the effectiveness of using copper sulfate (CuSO4) as a drench in Hampshire ewes to control stomach worms (Haemonchus contortus). A study was conducted to assess the effectiveness of CuSO4 to control gastrointestinal nematodes (GIN) over a three year period. Ewes were FAMACHA scored, hematocrit evaluated for packed cell volume (PCV), and fecal egg counts (FEC) were determined from 2007 through 2009. Ewes received only CuSO4 to control GIN. Ewes with FEC exceeding 6,000 eggs/g feces were drenched. A separate study during the summer of 2008 assessed the potential of CuSO4 drench to cause copper toxicity in Hampshire ewes. Eighty-four ewes were blocked to one of two treatments according to parity and balanced for FEC. One group received CuSO4 (D) and the other was not drenched (ND). Jugular blood samples were collected at pre-determined intervals after CuSO4 was administered to D ewes. Serum was analyzed for aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatine kinase (CK). Elevated serum levels indicate copper toxicity. Results suggest CuSO4 has the potential to control stomach worms in Hampshire ewes without causing copper toxicity.

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Wang, Xiaoyan. "Synucleins and their roles in the pathology of Parkinson's disease as metal binding proteins." Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512329.

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α-synuclein is an abundant and conserved presynaptic brain protein (Uversky 2007). It has received extensive attention since its aggregation was identified as the main component of Lewy bodies and Lewy neurites, which is the pathological hallmark of several neurodegenerative diseases, collectively known as synucleinopathies, including Parkinson's Disease (PD) (Uversky 2007). Considerable information has been collected about the structural properties and conformational behavior of α-synuclein, although the precise function is still under investigation. Metal ions such as copper and iron, can accelerate the aggregation and fibrillation of α-synuclein. Metal ions may exert their dual physiopathological properties through the interaction with α-synuclein, converting protein structure and/or inducing oxidative stress. In this study, isothermal titration calorimetry and electron paramagnetic resonance were used to determine the metal-binding property of the synuclein proteins, proving the presence of four Cu(II) binding sites per molecular of α-synuclein, with the coordination modes of 1N3O and 2N2O. Furthermore, α-synuclein has a catalytic action on the redox cycling of Cu(II), which was assessed by the application of cyclic voltammetry. However, this property is absent on β-synuclein and γ-synuclein, which belong to the synuclein family and have been suggested to be the physiological regulators of α-synuclein expression. In vivo, immunofluoresence studies revealed that Cu(II) increases the aggregates formation in mammalian doperminergic neuron cells overexpressing α-synuclein and the PD-associated mutants, while no aggregates have been found in cells overexpressing β-synuclein and γ-synuclein.

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Dagan, Roi. "Metal attenuation and toxicity reduction of chromated copper arsenate pressure treated wood leachate by three Florida soils." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001205.

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Kahokola, K. V. "The effect of copper, arsenic and chromium on plants and the use of the water cooled atom trap as a preconcentration technique." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384436.

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Garris, Heath W. "Feed comparison for dietary standardization of the sea urchin Lytechinus variegatus and assessment of parental dietary copper toxicity by fertilization and embryological tests." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008m/garris.pdf.

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Thesis (M.S.)--University of Alabama at Birmingham, 2008. Additional advisors: Marion Nipper, Robert A. Angus, Addison L. Lawrence. Description based on contents viewed May 30, 2008; title from title screen. Includes bibliographical references.

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McCann, Mary T. "Toxicity of zinc, copper, and sediments to early life stages of freshwater mussels in the Powell River, Virginia." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07112009-040226/.

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Galyas, Éva. "Concentrations of lead, copper and zinc in forest soils near industrial areas." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40363.

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Environmental contamination with heavy metals, especially of soils, has been a continuousproblem worldwide since the beginning of the industrial revolution. Heavy metal emissionshave increased continuously since 1900 and the metals accumulate in the environment. Pulpand paper mill factories, and factories which produce sulphuric acid emit heavy metals,among others lead (Pb), copper (Cu) and zinc (Zn). Results from previous studies showedthat the soils near factories had higher concentrations of these pollutants than the controlplace. In this study I want to determine the effects of industrial heavy metal emissions of onehistoric and one present industry on nearby soil heavy metal concentrations.Samples were taken near one historically heavily contaminated site, the old sulphite factoryin Rydöbruk (1897-1944) and near the present Stora Enso paper mill in Hyltebruk. As acontrol site, I compared these with Rocknen nature reserve area.At each site I took 6 soil samples, representing the top 15-20 cm of soil and organic material.Samples were analysed with an Atomic Absorption Spectrometer and the concentrations oflead, copper and zinc were determined per ashed dry material.I analyzed the samples at the laboratory using the guideline from the Swedish StandardInstitute for water analysis.The concentrations of the soil samples showed no significant difference between the naturereserve area and the industrial sites (One-way ANOVA). This was due to very variableorganic content within and between the sites.Organic content of the samples has a significantly effect on the metal concentrations for Pband Cu (Linear Regression test). In conclusion, metals can accumulate in the vegetation, andin case of Pb and Cu there is a correlation between their concentration and the amount oforganic matter. Therefore in future studies it is best if soil with very high organic content orvegetation is used to determine if forest soil near industries are affected by past or presentindustrial emissions of heavy metals.

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Weaver, Meghan C. "Effects of Copper Sulfate Application on Zooplankton and Macroinvertebrate Communities in Upground Reservoirs." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1339094079.

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Lai, Ian Kwan-Tai. "Using dietary strategies to explore mechanisms of hepatic toxicity caused by 3,3',4,4',5-Pentachlorobiphenyl (PCB 126) in an animal model." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1157.

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This doctoral dissertation work strived to contribute to the ever expanding knowledge about the mechanisms of polychlorinated biphenyl (PCB) toxicity using dietary strategies. PCBs are a family of persistent environmental pollutants with a wide range of toxicity. The toxicity of PCBs is largely dependent on the congener's chlorination pattern. Of particular interest to this work was 3,3',4,4',5-pentachlorobiphenyl (PCB 126), the most potent of the dioxin-like PCB congeners. I hypothesized that in vivo PCB 126 toxicity will be ameliorated by dietary selenium supplementation, lowered dietary copper, and dietary N-acetylcysteine (NAC) supplementation. Dioxin-like PCBs are known for diminishing hepatic selenium and selenium-dependent glutathione peroxidase (SeGPx), an antioxidant enzyme. In the first study, PCB 126 caused a dose-dependent decrease in hepatic selenium and SeGPx. Supplemental dietary selenium significantly increased hepatic selenium and SeGPx, and decreased incidence of apoptosis in these rats. The results from this study support that selenium plays a protective role, and differences in liver injuries of these rats may be reflected in their selenium status. The dose-dependent increase in hepatic copper caused by PCB 126 was a subject of interest and concern in the next study. Lowering dietary copper levels without negatively affecting the function of the essential antioxidant enzyme copper zinc superoxide dismutase did not result in reduction of PCB 126-induced toxicity. Copper metabolism was unlikely a main target of PCB 126 toxicity as increasing dietary copper did not significantly increase hepatic copper levels. Hepatic copper is highly regulated and likely does not play a significant role in PCB 126-induced toxicity. The effectiveness of NAC on restoring glutathione status and reducing PCB 126 toxicity was tested in the final study. While NAC did not restore glutathione status, NAC supplemented rats had significantly reduced severity of PCB 126-induced liver status. The results of this study are consistent with the theory that NAC has a glutathione-independent effect in improving mitochondrial energy metabolism. It also suggests that PCB 126-induced mitochondrial metabolic disruption of the liver is of greater concern than oxidative stress.

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Schwertfeger, Dina. "The effects of soil leaching on metal bioavailability, toxicity and bioaccumulation in «hordeum vulgare» cultivated in copper amended soils." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=96995.

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Discrepancies in ecotoxicity effects data derived from soils amended with dissolved metals in the laboratory and soils from historically aged metal-contaminated sites pose a challenge in deriving environmentally relevant soil quality criteria. In this thesis, the chemical artefacts produced by dissolved metal additions and the subsequent effects on metal bioavailability, toxicity and bioaccumulation are examined. The overall goal of this research is to advance the understanding of soil trace metal bioavailability mechanisms and improve current methods for ecotoxicity testing and bioavailability modeling. The first objective was to develop a leaching method which would minimize the "salt-effect" commonly observed in freshly-spiked soil samples. This was achieved by adapting a column leaching procedure in order to spike and leach larger volumes of test soil as a preparatory step prior to ecotoxicity assays. An experiment was set up to observe changes to leachate chemistry resulting from the dissolved Cu additions and subsequent leaching with two weak electrolyte solutions. Results showed that leaching removed the excess dissolved Cu as well as the excess acidity and base cations that were solubilized during the Cu additions. Differences between control and spiked samples of some key soil solution parameters (e.g. pH, DOC and total dissolved Ca, Mg, Al, Fe) were reduced thereby resulting in a set of spiked samples more conducive to deriving causal dose-response relationships. A second experiment compared soil and soil solution properties of samples which underwent the spike/leach procedure to those of freshly spiked samples. Lower soil pH (up to 0.81 pH units) and DOC concentrations were observed in non-leached samples as well as up to 35-fold and 55-fold increases of dissolved Ca and Mg concentrations, typical of the salt-effect. It was estimated that the non-leached samples contained up to 100-fold greater Cu2+ and 50-fold greater Al3+ activities which, I hypothesized, could result in greater phytotoxicity of non-leached samples. Bioassays were conducted wherein Hordeum vulgare (barley) seedlings were exposed to the leached and non-leached Cu-spiked soil samples for 14 days. The leached samples were less toxic to barley and showed significant increases (up to 1.7-fold) in median inhibitory concentrations (i.e. IC50) for root elongation in two of the three test soils. The Cu2+ fraction was able to explain much of the variability in toxicity between leached and non-leached samples, as well as among the different test soils. One exception was the most acidic test soil for which plants in the leached samples showed up to 10-fold greater toxicity than plants in the non-leached samples, when exposed to similar Cu2+ activities. Soil speciation and bioaccumulation data for Cu, Al and Ca were used to deduce that Ca deficiency and possibly Al toxicity contributed to the toxicity observed in this sample set. In a modeling exercise, the concepts of the terrestrial biotic ligand model (TBLM), which take into account ion competition at the soil solution/root interface, to describe toxic response in our samples. Results showed that the additive effects of Cu and Al toxicity estimated from the Cu-root ligand complex (Cu-BL+) and Al-root ligand complex (Al-BL2+) accounted for more of the variability in toxic response data than did the Cu2+ fraction or the Cu-BL+ fraction alone. The model however, could not account for the effects of the Cu-induced Ca deficiency in the most acidic test soil, thus highlighting one of the limitations of the TBLM. This thesis has contributed to the understanding of metal bioavailability mechanisms affected by soil spiking procedures and highlights the benefits of soil leaching in preparing soil samples for ecotoxicity assays which should improve trace metal risk assessment in the future. La nature hétérogène et multiphasique du sol présente de nombreux défis lors de l'évaluation des risques que posent les sols contaminés par des métaux à la santé humaine et environnementale. Il existe plus particulièrement 1) une très grande variation dans les données sur les effets écotoxicologiques basés sur la concentration totale des métaux dans le sol et 2), de grands écarts entre les données sur les effets écotoxicologiques de sols amendés (de métaux) en laboratoire et celles de sols contaminés provenant de sites naturels existants (ex. : sols provenant de champs contaminés). Cette thèse examine les composés chimiques obtenus par l'amendement (de métaux) de sols en laboratoire ainsi que leurs effets sur la biodisponibilité des métaux, leur toxicité et leur bioaccumulation. Le but de cette recherche est d'augmenter les connaissances et la compréhension des mécanismes régissant la biodisponibilité des métaux dans les sols ainsi que d'améliorer les méthodes d'évaluation écotoxicologiques et de production de modèles de biodisponibilité. L'un des premiers objectifs fut de développer une technique de filtration des sols minimisant le "salt effect" régulièrement observé chez les échantillons fraîchement amendés. Une technique de filtration par colonne fut alors adaptée afin d'amender de plus grands volumes d'échantillons de sols en préparation aux tests écotoxicologiques. La première expérimentation consistait à observer les changements survenus aux résidus de filtration dont l'échantillon avait été additionné de Cu et ensuite filtré par deux solutions électolytes faibles. Les résultats ont démontré que la filtration avait, en effet, retiré le Cu en excès, l'acidité excessive ainsi que des cations basiques solubilisés lors de l'addition de Cu. Les différences observées entre les échantillons contrôles et ceux amendés pour quelques paramètres clés des résidus de filtration (pH, COD, quantité totale dissoute de Ca, Mg, Al et Fe) se sont trouvées minimisées, justifiant ainsi l'utilisation des échantillons amendés pour la dérivation d'une relation de cause à effet dosage-réponse. La deuxième expérimentation consistait à comparer les propriétés des sols et des solutions de sols des échantillons ayant été amendés et filtrés avec ceux amendés mais non-filtrés. Des données de pH (jusqu'à 0,81 unités de pH) et de concentrations de COD très basses furent observés pour les échantillons non-filtrés et des concentrations de Ca et de Mg de 35 à 55 fois plus élévées pour les échantillons non-filtrés que pour les échatillons filtrés (typiques du "salt-effect"). Nous avons d'ailleurs pu estimer que les concentrations de Cu2+ étaient jusqu'à 100 fois supérieures et celles de Al3+ jusqu'à 50 fois supérieures dans les solutions de sols non-filtrés ce qui nous permet de croire que leur phytotoxicité en est grandement augmentée. Nous comparons les résultats de tests biologiques exercés sur des pousses de Hordeum vulgare (orge) soumises aux sols amendés de Cu, filtrés et non-filtrés, pendant 14 jours. Les échantillons de sols filtrés se sont avérés moins toxiques pour l'orge et ont fourni des résultats médiens de concentration d'inhibiteurs (IC50) jusqu'à 1,7 fois supérieurs pour la longueur des racines dans deux des trois tests de sol. La quantité de Cu2+ suffisait à elle seule à expliquer la majorité des variations de toxicité entre les échantillons filtrés et non-filtrés de même qu'entre les différents tests de sol. La seule exception fût observée pour le plus acide des sols pour lequel les plantes des échantillons filtrés se sont avérées 10 fois plus toxiques que celles des échantillons non-filtrés lorsqu'exposées à des niveaux de Cu2+ similaires. Les données de caractérisation du sol et de bioaccumulation de Cu, Al et Ca ont été utilisées afin de déterminer qu'une carence en Ca, et possiblement des niveaux toxiques de Al, ont contribué à la toxicité observée dans les échantillons de sol.

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42

Schwertfeger, Dina. "The effects of soil leaching on metal bioavailability, toxicity and accumulation in Hordeum vulgare cultivated in copper amended soils." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115837.

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Discrepancies in ecotoxicity effects data derived from soils amended with dissolved metals in the laboratory and soils from historically aged metal-contaminated sites pose a challenge in deriving environmentally relevant soil quality criteria. In this thesis, the chemical artefacts produced by dissolved metal additions and the subsequent effects on metal bioavailability, toxicity and bioaccumulation are examined. The overall goal of this research is to advance the understanding of soil trace metal bioavailability mechanisms and improve current methods for ecotoxicity testing and bioavailability modeling. The first objective was to develop a leaching method which would minimize the "salt-effect" commonly observed in freshly-spiked soil samples. This was achieved by adapting a column leaching procedure in order to spike and leach larger volumes of test soil as a preparatory step prior to ecotoxicity assays. An experiment was set up to observe changes to leachate chemistry resulting from the dissolved Cu additions and subsequent leaching with two weak electrolyte solutions. Results showed that leaching removed the excess dissolved Cu as well as the excess acidity and base cations that were solubilized during the Cu additions. Differences between control and spiked samples of some key soil solution parameters (e.g. pH, DOC and total dissolved Ca, Mg, Al, Fe) were reduced thereby resulting in a set of spiked samples more conducive to deriving causal dose-response relationships. A second experiment compared soil and soil solution properties of samples which underwent the spike/leach procedure to those of freshly spiked samples. Lower soil pH (up to 0.81 pH units) and DOC concentrations were observed in non-leached samples as well as up to 35-fold and 55-fold increases of dissolved Ca and Mg concentrations, typical of the salt-effect. It was estimated that the non-leached samples contained up to 100-fold greater Cu2+ and 50-fold greater Al3+ activities which, I hypothesized, could result in greater phytotoxicity of non-leached samples. Bioassays were conducted wherein Hordeum vulgare (barley) seedlings were exposed to the leached and non-leached Cu-spiked soil samples for 14 days. The leached samples were less toxic to barley and showed significant increases (up to 1.7-fold) in median inhibitory concentrations (i.e. IC50) for root elongation in two of the three test soils. The Cu2+ fraction was able to explain much of the variability in toxicity between leached and non-leached samples, as well as among the different test soils. One exception was the most acidic test soil for which plants in the leached samples showed up to 10-fold greater toxicity than plants in the non-leached samples, when exposed to similar Cu2+ activities. Soil speciation and bioaccumulation data for Cu, Al and Ca were used to deduce that Ca deficiency and possibly Al toxicity contributed to the toxicity observed in this sample set. In a modeling exercise, the concepts of the terrestrial biotic ligand model (TBLM), which take into account ion competition at the soil solution/root interface, to describe toxic response in our samples. Results showed that the additive effects of Cu and Al toxicity estimated from the Cu-root ligand complex (Cu-BL+) and Al-root ligand complex (Al-BL2+ ) accounted for more of the variability in toxic response data than did the Cu2+ fraction or the Cu-BL+ fraction alone. The model however, could not account for the effects of the Cu-induced Ca deficiency in the most acidic test soil, thus highlighting one of the limitations of the TBLM. This thesis has contributed to the understanding of metal bioavailability mechanisms affected by soil spiking procedures and highlights the benefits of soil leaching in preparing soil samples for ecotoxicity assays which should improve trace metal risk assessment in the future.

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Owojori, Olugbenga J. (Olugbenga John). "Influence of clay content and salinity on the bioavailability and toxicity of metals (copper and zinc) to soil organisms." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1484.

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Thesis (PhD (Botany and Zoology))—University of Stellenbosch, 2009. ENGLISH ABSTRACT: Metal pollution is a problem of increasing global concern. It could arise from industrial activities, as well as pesticide use in agriculture, among other sources. For adequate protection of the soil ecosystem from metal toxicity, the bioavailability of metals must be properly evaluated. A plethora of soil factors affect the bioavailability of metals to soil organisms. These include pH, clay and organic matter contents, salinity among others. While much is known about the influence of some of these parameters, little is known on how clay content and salinity modify the bioavailability of metals to soil organisms. This study investigated the influence of clay content and salinity on partitioning, uptake and toxicity of two essential metals (Cu and Zn) to the earthworm Eisenia fetida in separate laboratory trials. Partitioning of the metals was evaluated with 0.01 M CaCl2, DTPA (di-ethylene-triamine-penta acetic acid), and nitric acid extractions. The metal content of worms was determined by acid digestion, while growth, cocoon production, and mortality were used as endpoints showing toxicity to metals and/or salinity. To test the validity of some of the laboratory results, a field study was undertaken, using the earthworm Aporrectodea caliginosa. Further, the study assessed the effect of salinity, using a battery of laboratory tests (acute, chronic and avoidance tests) with natural and/or artificial soils on four species of organisms (a collembolan Folsomia candida, a potworm Enchytraeus doerjesi and two earthworm species E. fetida and A. caliginosa), representing different feeding patterns and ecological roles in soil. Results showed that with increased clay content, there was increased availability of Cu in the substrate, and increased toxicity to E. fetida as shown by data for mortality and growth. The situation with Zn was less significant at sub-lethal concentrations but much so at lethal concentrations. DTPA and CaCl2 extracted metals revealed changes in partitioning of Cu and Zn with changes in clay content, but this trend was not always consistent. Both DTPA and CaCl2 revealed increased availability of Zn in substrates with increased salinity. Salinity had an additive to synergistic effect with Zn in toxicity to E. fetida. When combined with Cu, salinity also increased the availability of Cu as shown by CaCl2 extracted fraction, and had additive effect on toxicity of Cu to the earthworm. The field study did not succeed in in iv confirming the results of the laboratory study due to confounding role of flooding after heavy rainfall and subsequent leaching of salts and Cu. The results of the experiment on acute and chronic toxicity tests for NaCl on E. fetida showed LC50 of 5436 mg/kg NaCl and EC50 for growth and cocoon production of 4985 and 2020 mg/kg NaCl. These values showed that earthworms might be negatively affected in many soils containing fairly moderate concentrations of salts. Similarly, A. caliginosa could not survive in natural soil containing relatively low salt concentrations (EC = 1.62 dS/m) while reproduction was severely affected at lower EC value of 0.52 dS/m. F. candida and E. doerjesi could survive in the highest salinity soil (EC = 1.62 dS/m) used in this study but their reproduction was severely affected from 1.03 dS/m. Overall, it appears that of all the taxa used, earthworm species were the most sensitive to saline stress and could proof useful in determining ‘safe levels’ of salt in contaminated soils. The results of the avoidance test showed that A. caliginosa avoided both natural and artificial saline soil containing concentrations lower than those avoided by E. fetida. The conclusion is that the influence of clay content and salinity on the bioavailability of Cu and Zn depends largely on the metal in question, but generally speaking, bioavailability and toxicity of the metals were reduced with increased clay content while the opposite was true for salinity. If the species used in this study can be seen as fairly representative of a wide range of soil organisms, the conclusion is that salinisation of soil will be detrimental to most soil organisms at relatively low saline concentrations. Given the role of beneficial soil organisms in several soil processes which in turn contribute to soil fertility and sustainable use of land, it is recommended that any farming practices that may lead to an increase in salt content of agricultural soils should be discouraged. AFRIKAANSE OPSOMMING: Metaalbesoedeling is ‘n probleem wat toenemende globale kommer veroorsaak. Dit kan ontstaan as gevolg van industriële aktiwiteite sowel as van plaagmiddelgebruik in die landbou en ander bronne.Ten einde die grondekostelsel genoegsaam te beskerm, moet die biobeskikbaarheid van metale ge-evalueer word. ‘n Verskeidenheid van grondfaktore be-invloed die biobeskikbaarheid van metale vir grondorganismes Hulle sluit onder andere in pH, klei, organiese inhoud en soutgehalte. Hoewel heelwat bekend is oor die rol van sommige van hierdie parameters, is min bekend oor hoe klei en soutgehalte die biobeskikbaarheid van metale vir grondorganismes kan modifieer. Hierdie studie het die invloed van kleiinhoud and soutgehalte op die verdeling/partisie, opname en toksisiteit van twee essensiële metale (Cu en Zn) vir die erdwurm Eisenia fetida in afsonderlike laboratoriumproewe ondersoek. Kompartementele verdeling van die metale is geevalueer deur middel van ekstraksie-metodes met 0.01 M CaCl2, DTPA (di-etileentriamien- penta asysnsuur), en salpertersuur ekstraksies. Die metaalinhoud van wurms is bepaal deur suurverterings en spektrofotometriese analises te doen terwyl groei, kokonproduksie en mortaliteit van organismes gebruik is as gevoeligheidseindpunte om toksisiteit van metale en soutgehalte aan te toon. Om die geldigheid van somige van die laboratoriumresultate te toets, is ‘n veldstudie ook onderneem met die erdwurm Aporrectodea caliginosa. Die effek van soutgehalte is verder ondersoek deur ‘n battery van laboratoriumtoetse met vier spesies (‘n kollembool Folsomia candida,’n potwurm Enchytraeus doerjesi en twee erdwurmspesies E. fetida en A. caliginosa), wat verskillende voedingspatrone verteenwoordig. Die resultate het getoon dat met toenmende klei-inhoud was daar ‘n toename in die beskikbaarheid van Cu vir opname vanuit die substraat, asook ‘n toename in toksisiteit vir E. fetida soos deur die gegewens vir mortaliteit en groei uitgewys. Die situasie met Zn was minder betekenisvol by subletale konsentrasies en selfs baie minder so by letale konsentrasies. DTPA en CaCl2 ge-ekstraheerde metale het veranderinge in die partisie/verdeling van Cu en Zn uitgewys met verandering in klei-inhoud, maar die tendens was nie altyd konstant nie. Beide DTPA en CaCl2 ekstraksie het toenemende beskikbaarheid van Zn in substrate uitgewys met toenemende soutinhoud. Soutinhoud het ‘n additiewe/toegevoegde tot sinergistiese vi toksisiteitseffek saam met Zn vir E. fetida. In kombinasie met Cu het soutgehalte ook die geskatte biobeskikbaarheid van Cu verhoog soos uitgewys deur die CaCl2, geekstraheerde fraksie, en het ‘n additiewe effek gehad op die toksisitiet van Cu vir die erdwurm. Die veldstudie kon nie die resultate van die laboratoriumstudie bevestig nie weens die belemmerende rol van vloede na swaar reënneerslae en daaropvolgende uitloging van soute en Cu. Die resultate van die eksperimentele ondersoek na die akute en chroniese effekte van NaCl op E. fetida het ‘n LC50 van 5436 mg/kg NaCl en EC50 vir groei en kokonproduksie van 4985 en 2020 mg/kg NaCl opgelewer. Hierdie waardes het aangetoon dat erdwurms moontlik negatief beinvloed kan word in baie gronde wat ‘n redelike gemiddelde konsentrasie van soute bevat. Soortgelyk kon A. caliginosa nie oorleef in natuurllike grond wat relatief lae soutkonsentrasies bevat het (EC=1.62 dS/m) nie terwyl voortplanting sterk ge-affekteer is by ‘n lae EC waarde van 0.52 dS/m. F. candida en E. doerjesi kon oorleef in die grond met die hoogste soutgehalte (EC= 1.62 dS/m) maar hulle voortplanting is ernstig geknou vanaf 1.03 dS/m. In geheel blyk dit dat van allle taksa wat gebruik is, erdwurms die sensitiefste was vir die stres wat deur soutgehalte veroorsaak is. Die kennis kan nuttig wees in die bepaling van “veilige vlakke” van sout in gekontamineerde gronde. Die resultate van die vermydingstoetse het getoon dat A. caliginosa beide natuurlike en kunsmatig versoute gronde vermy het by konsentrasies wat heelwat laer was as dié wat deur E. fetida vermy is Die gevolgtrekking is dat die invloed van klei en soutgehalte op die biobeskikbaarheid van Cu en Zn grootliks afhanklik is van die metale wat betrokke is en dat biobeskikbaarheid en toksisiteit normaalweg verminder het met verhoogde klei-inhoud, met die teenoorgestelde wat waar was in die geval van soutgehalte. Indien die spesies wat in die studie gebruik is beskou kan word as redelik verteenwoordigend van ‘n wye reeks van grondorganismes, is die gevolgtrekking dat versouting van gronde nadelig sal wees vir meeste grondorganismes, selfs by relatief lae soutkonsentrasies. In die lig van die rol wat nuttige grondorganismes speel in verskeie grondprosesse wat bydraend is tot grondvrugbaarheid en volhoubare gebruik van gronde, word dit aanbeveel dat enige boerderypraktyk wat mag lei tot verhoging van die soutinhoud van landbougronde ontmoedig moet word.

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Vaz, Cristiana Lourenço de Oliveira. "Efeitos do cobre no sargo (Diplodus sargus, Linnaeus 1758) : implicações quer a nível fisiológico, quer de crescimento." Master's thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2011. http://hdl.handle.net/10400.5/4234.

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Dissertação de Mestrado em Engenharia Zootécnica-Produção Animal O recente crescimento da aquacultura, juntamente com a introdução de novas espécies de peixes em sistemas de produção intensivos, levou a um aumento da ocorrência e diversidade de agentes patogénicos. O sulfato de cobre tem sido amplamente utilizado para a prevenção e controlo de ectoparasitas, contudo, pode tornar-se tóxico a altas concentrações, comprometendo a integridade fisiológica dos peixes. Deste modo, o objectivo deste estudo foi analisar os efeitos de diferentes concentrações de cobre a nível da toxicidade deste sobre diferentes tecidos, a nível do crescimento e comportamento de juvenis de sargo (Diplodus sargus). Neste estudo, os indivíduos foram, durante um período de 23 dias, expostos a 0,2 mg L-1, 0,5 mg.L-1 e 1 mg.L-1 de cobre. Num segundo ensaio submeteram-se juvenis de sargo com um peso médio de 70,71 ± 18,89 g a concentrações de cobre de 0,25 mg.L-1 e 0,5 mg.L-1, durante 60 dias. Os resultados demonstraram que a concentração de cobre no fígado difere significativamente entre os tratamentos testados e, que no músculo não existiam diferenças significativas. As observações dos tecidos revelaram diversas alterações ao nível da estrutura do tecido branquial e hepático, entre os indivíduos expostos a diferentes tratamentos. O grau de alterações morfológicas observadas diferiu de acordo com o período de exposição e com o tratamento experimental. No entanto, também foram detectadas alterações de intensidade variável entre indivíduos expostos ao mesmo tratamento. Estas serão, possivelmente, devido a diferentes mecanismos de adaptação às diferentes concentrações. O tratamento prolongado com cobre não parece influenciar o crescimento dos indivíduos. A análise comportamental reflecte que houve diferenças significativas entre os indivíduos controlo e os indivíduos expostos ao cobre, na quantidade de alimento consumido. ABSTRACT - Effects of copper on white seabream (Diplodus sargus, Linnaeus 1758):physiological implications and growth - The recent growth of aquaculture and the introduction of new species of fish in intensive production systems, contributed to the occurrence of more and new pathogenic agents. Copper sulfate has been widely used for the prevention and control of parasites. However, it can be toxic at high concentrations, compromising the physiologic integrity of the fish. The objective of this study the effects of the copper in the tissues, in the growth and in the behavior of juvenile sea bream (Diplodus sargus). In this study, the fish were exposed, during a period of 23 days, to 0.2 mg.L-1, 0.5 mg.L-1 and 1 mg.L-1 of copper. In a second trial, juvenile sea bream, with an average weight of 70.71 ± 18.89g, were submitted to concentrations of copper of 0.25 mg.L-1 and 0.5 mg.L-1 for 60 days. The results show that the concentration of copper in the liver is significantly different among the treatments. In the muscle, there were no significant differences. In the tissues, it was observed several changes on the normal structure of the gills and of the hepatic tissues, among the individuals exposed to different treatments. The degree of morphological changes was different according to the period of exposure and to the experimental treatment. We also detected variable level changes among individuals exposed to the same treatment. It suggests that might exist different adaptation mechanisms, dependent on the copper concentrations. The duration of the copper treatment doesn't seem to influence the growth of the fish. The behavioral analysis, regarding the amount of food consumed shows that there were important differences in the group subjected to copper treatment when compared to the control group.

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McManus, Paul. "Rhizosphere Interactions Between Copper Oxide Nanoparticles and Wheat Root Exudate in a Sand Matrix; Influences on Bioavailability and Uptake." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5058.

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Copper oxide nanoparticles (NPs) are used in an expanding range of industries including a potential for agricultural applications as a fungicide. Accidental spills or misapplication of CuO NPs may lead to soil contamination. Plant roots exude a wide range of organic chemicals for bioprotection and to enhance bioavailability of nutrients. Many of these chemicals are metal chelators that may increase the solubility of CuO NPs, thus enhancing the impact of these NPs on plants. This work was directed towards understanding which plant exudates force increased solubility of CuO NPs and to determine if the level of NP in the growth matrix drives a feedback effect, regarding composition and quantity of exudates. Wheat seedlings (Triticum aestivum cv Deloris) were grown in a sand matrix for 10 days after 3 days of germination. The sand was amended with sublethal doses of CuO NPs from 0 to 300 mg Cu/kg dry sand. Sand was selected as the solid growth matrix as a proxy for soil in terms of plant root morphology, mechanical impedance and water stress, while providing a low background of dissolved organic carbon for the isolation of root exudates. After plant growth, the pore water was collected from the sand by vacuum filtration and analyzed. By coupling analytic techniques including Triple Quad Mass Spectroscopy and ion chromatography with geochemical modeling, we have identified citrate and the phytosiderophore, deoxymugineic acid (DMA) as chelators that drove the majority of dissolution of CuO NPs, especially DMA at higher CuO NP doses. Altered biogeochemistry within the rhizosphere was correlated with increased plant uptake of Cu and bio-response via exudate type, quantity and metal uptake. Exposure of wheat to CuO NPs lead to dose-dependent reduction in Fe, Ca, Mg, Mn and K in roots and shoots. This work is relevant to growth of commercially important crop wheat in the presence of CuO NPs as a fertilizer, fungicide or a pollutant.

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Kaiser, Sibylle Martina. "Interactions of copper and hydrophobic ionogenic organic pollutants in biological membranes and their consequences for bioavailability and toxicity towards algae /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17043.

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Postlethwait, Niel Holland. "Evaluation of Chelex 100 and Assessing the Impact of Fulvic Acid (NOM) on Copper Toxicity and Bioavailability to Americamysis bahia." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33811.

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A cation exchange method (Chelex 100) that distinguishes weakly bound and strongly bound copper was investigated for its ability to measure bioavailable copper in estuarine waters. Copper bound to the Chelex 100 resin was operationally defined as bioavailable copper. Varying initial copper concentration from 195 to 495 ug/L at a constant 12.5 mg/L natural organic matter (NOM) did not affect percent bioavailability. There were also no noticeable effects when varying total Cu concentration in the presence of 0, 12, and 24 mg/L NOM. An increase in pH from 4 to 8.5 and NOM from 0 mg/L to 12.5 mg/L reduced percent bioavailability. Using the Chelex 100 resin to measure bioavailable copper, about 20 to 40% of the total copper was bioavailable in the absence of NOM, while about 15 to 20% was bioavailable when either 12 or 24 mg/L NOM was present. Acute toxicity bioassays were performed with mysid shrimp (Americamysis bahia) to evaluate the toxic effects of copper in the presence of Suwannee River Fulvic Acid, which served as a source of NOM. Static or static renewal tests, based on EPA method OPPTS 850.1035 with a minimum of 10 mysid shrimp per test condition, were used to determine the LC50 and EC50 of copper and the effects of NOM. Test solutions consisted of artificial synthetic seawater at 20 parts per thousand containing concentrations of 0, 100, 200, 400, 800 ug/L copper with either 0, 12, 24 mg/L NOM. Forty-eight hour acute toxicity tests were performed on larval (2 to 3 day) mysid shrimp that were fed Artemia (brine shrimp); mortality and immobilization were the endpoints. The 48 hour LC50 was 200 ug/L dissolved Cu and 94 ug/L bioavailable Cu without NOM, 340 ug/L dissolved Cu and 98 ug/L bioavailable Cu when 12 mg/L NOM was present, and 495 ug/L dissolved Cu and 105 ug/L bioavailable Cu at 24 mg/L NOM. The consistency of the LC50 measurement using bioavailable Cu suggest that the Chelex 100 resin is a useful technique for toxicity analysis in saline water. Master of Science

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Balinski, Michael A. "Differential Sexual Survival of D. Melanogaster on Copper Sulfate." Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1462973269.

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Shaw, Benjamin John. "The ecotoxicology of engineered nanoparticles to freshwater fish." Thesis, University of Plymouth, 2011. http://hdl.handle.net/10026.1/565.

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The use of nanoscale materials is growing exponentially, but there are also concerns about the environmental hazard to aquatic biota. Metal-containing engineered nanoparticles (NPs) are an important group of these new materials, and whilst there are undoubtedly a plethora of beneficial uses for these NPs, it is essential that an appropriate risk assessment is carried out in order to protect the environment and human health, with the consumption of contaminated fish a distinct possibility. The current study aimed to assess the bioavailability, uptake and toxicological effects of two metal-NPs (TiO2 NPs and Cu-NPs) to fish from both dietary and waterborne exposure routes and where appropriate compare them to their bulk counterpart. Whole body system effects were assessed along with the influences of the life stage of exposed fish and abiotic factors on toxicity. A technique to improve the quantification of Ti from TiO2 NPs in fish tissue was also developed. Effects from exposure to dietary TiO2 NPs manifested similarly to traditional dietary metal exposure, with no reduction in growth, but some sublethal affects. Exposure to waterborne Cu-NPs showed that rainbow trout were more acutely sensitive to CuSO4 than the NPs, but that despite limited uptake several body systems were affected (most notably ionoregulation). Larvae were more sensitive to CuSO4 than Cu-NPs, but no differences were seen with embryos, whilst larvae were more sensitive than embryos. Abiotic factors did have an effect on acute Cu-NP toxicity, though not always in a predictable manner, with some effects more pronounced than with CuSO4. Overall, it appears that metal-NPs are not as acutely toxic as their bulk counterparts, but sublethal effects, were routinely observed. As TiO2 NPs appear more toxic than its bulk counterpart, current legislation governing safe environmental limits may have to be adjusted, though the situation with Cu-NPs isn’t as clear and further investigation is required. However, the risk of human exposure via the consumption of NP contaminated fish fillets is extremely low.

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Frese, Thomas Jay. "Acute toxicity of copper sulfate in juvenile red drum (Sciaenops ocellatus) and the establishment of safe methods to control parasitic disease." FIU Digital Commons, 1994. http://digitalcommons.fiu.edu/etd/3418.

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A series of static 96 hour acute toxicity tests were performed on juvenile red drum of different sizes. The tests were implemented to assess the acute toxicity of copper sulfate to juvenile red drum and establish narrowly defined guidelines for its usage in the treatment of Amyloodinium ocellatum and Cryptocaryon irritans. Median lethal concentrations at which a 50 percent mortality response (LC5 o) were observed ranged from 0.28 mg/1 to 0.88 mg/l in the series of five 96h static acute toxicity tests. A significantly higher sensitivity was observed in early juveniles (2.9 g, 53.3 mm) versus the test runs using older juveniles (11.9, 24.4, 24.7, and 34.4 g). Based on the results of acute toxicity tests and actual experimental treatment regimes performed throughout this study, administration of 0.4 mg/1 CuSO4 for 3h daily over a 14d duration is believed to be a relatively safe, yet effective dose for maturing juvenile red drum.

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