Dissertations / Theses: 'Bioaccumulation of heavy metals'

1

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

2

Erickson, Lucas Erickson. "ACCUMULATION OF ENVIRONMENTAL AND DIETARY HEAVY METALS BY THEWOLF SPIDER PARDOSA MILVINA (ARANEAE, LYCOSIDAE)." Miami University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=miami1541540077052724.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Stoll, Anita. "Bioaccumulation of heavy metals by the yeast S. cerevisiae and the bioremediation of industrial waste water." Thesis, Rhodes University, 1997. http://hdl.handle.net/10962/d1004075.

Full text

Abstract:

Water is an essential element in all aspects of life and is vital for both domestic and industrial purposes regarding both the quality and quantity thereof. Similar to many other drought stricken countries, South Africa requires water for the socio-economic growth of the country, yet is faced with the problem of maintaining the quality of its drinking water as well as protecting the dwindling supplies. In an attempt to prevent the deterioration of South African water supplies the treatment, purification and recycling of industrial and mining waste water has recently become of prime importance. Many industrial and mining waste waters contain heavy metals in toxic quantities. The conventional processes that have been used till recently to address this problem, are often expensive or contain chemical agents which compound the environmental problem. As an alternative biological methods of metal accumulation appear to offer an economic and efficient alternative to these methods. An advantage to the South African scenario is the commercial production of the yeast, S. cerevisiae as a readily inexpensive by-product from some fermentation industries, Yeast cells, and in particular S. cerevisiae have proven to be capable of accumulating heavy metals, and therefore exhibit potential application in the bioremediation of waste water. The aim of this project was twofold. The initial part of this work attempted to define the mechanisms of metal accumulation by the yeast cells and cellular components. The information obtained from these initial studies provided a data base required for the development of a bioremediation system. Initial contact with the metal ions occurs at the wall interface of the yeast cell. Metal accumulation appears to be a function of all the cell wall components. The isolated cell wall components are better metal chelators then the intact cell walls. An apparent affinity series of mannan > chitin> glucan > intact cell walls exists. However, these components differ in their affinities for metal ions. Storage of metal ions within the cell occurs predominantly in the vacuole. The present study concluded that metal accumulation by the vacuole could be related to size. Metal accumulation occurred in the order of Cu2+ > Co2+ > Cd2+ with a corresponding decrease in atomic radii of Cd2+ > C02+ > Cu2+. Vacuolar ion deposition occurs at an early stage during the internalization of metal ions within the yeast cells. At the onset of vacuolar saturation, depositions of metal ions as granules within the cytosol occurs. In the presence of heavy metal cations viable yeast cells can be shown to exhibit two types of cellular responses. Uptake of Cu2+ and Cd2+ causes the loss of intracellular physiological cations from within the yeast cell. In comparison, uptake of Co2+ into the cell does not have this effect. All three heavy metal cations initiate plasma cell membrane permeability, thus the Cu2+ and Cd2+ induced loss of the intracellular cations, occurs. ~ a result of ion-exchange mechanisms and not due to cation leakage brought about by membrane permeabilization. Uptake of heavy metals by viable yeasts appears to be generally non-selective though the amount of metals accumulated are largely affected by the ratio of ambient metal concentration to biomass quantity. In addition, the energy dependent nature of internalization necessitates the availability of an external energy source for metal uptake by viable yeast cells. For these reasons metal removal from industrial waste water was investigated using non-viable biomass. By immobilizing the yeast cells additional mechanical integrity and stability was conferred apon the biomass. The three types of biomass preparations developed in this study, viz. polyvinyl alcohol (PV A) Na-alginate, PV A Na-orthophosphate and alkali treated polyethylenimine (PEI):glutaraldehyde (GA) biomass pellets, all fulfilled the necessary physical requirements. However, the superior metal accumulating properties of the PEI:GA biomass determined its selection as a biosorbent for bioremediation purposes. Biosorption of heavy metals by PEI:GA biomass is of a competitive nature, with the amount of metal accumulated influenced by the availability of the metal ions. This availability is largely determined by the solution pH. At low pH values the affinity of the biomass for metals decreases, whilst enhanced metal biosorption occurs at higher pHs, ego pH 4.5 - 6.0. PEI:GA biomass pellets can be implemented -as a biosorbent for the bi9remediaiton of high concentration, low-volume metal containing industrial waste. Several options regarding the bioremediation system are available. Depending on the concentration of the metals in the effluent, the bioremediation process can either be used independently or as part of a biphasic remediation system for the treatment of waste water. Initial phase chemical modification may be required, whilst two types of biological systems can be implemented as 'part of the second phase. The PEI:GA biomass can either be contained within continuous-flow fixed bed tanks or continuous-flow stirred bioreactor tanks. Due to the simplicity of the process and the ease with which scale-up is facilitated, the second type of system shows greater application potential for the treatment of this type of industrial waste water than the fixed-bed systems.

APA, Harvard, Vancouver, ISO, and other styles

4

Österås, Ann Helén. "Interactions between calcium and heavy metals in Norway spruce : accumulation and binding of metals in wood and bark /." Stockholm : Botaniska institutionen, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-81.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Eddleman, Katherine. "Bioaccumulation of Heavy Metals from Soils to Plants in Watersheds Contaminated by Acid Mine Drainage in SE Arizona." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/265334.

Full text

Abstract:

Current concerns about inorganic contaminants in food products have raised consumer awareness of anthropogenic sources of heavy metal contamination in ecosystems and their potential threat to human health. Mining and exploration of mineralized zones is a major source of such contamination. Mining throughout the Patagonia Mountains, Arizona, has left a legacy of surface water contamination by acid mine drainage (AMD). This study assessed the impacts of AMD on soils and plants throughout the study area. Concentrations, transport, and loading of heavy metals (Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, and Zn) in soils and plants was quantified using total concentrations, suggested toxic levels, and plant and soil pollution indices. Pollution indices were modified to include antimony and molybdenum. Pollution indices greater than 100 were found in areas disturbed by mining, remediation sites and beyond. Cattle grazing on grasses contaminated by metals were documented.

APA, Harvard, Vancouver, ISO, and other styles

6

Lai, Mei-yee, and 黎美兒. "Fractionation, mobilization and bioaccumulation of heavy metals and mineralogical characteristics of the Mai Po Inner Deep Bay mudflat." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29980069.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Giansante, Ruth Helena. "Potencial de Rizobactérias para a Remoção de Cádmio em Solução." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/153351.

Full text

Abstract:

Submitted by RUTH HELENA GIANSANTE null (ruthhgster@gmail.com) on 2018-04-03T13:04:19Z No. of bitstreams: 1 RUTH_GIANSANTE_DISS_versÃ£o final (20DEZ2017) (5)6.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5)
Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-03T18:23:48Z (GMT) No. of bitstreams: 1 giansante_rh_me_jabo.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5)
Made available in DSpace on 2018-04-03T18:23:48Z (GMT). No. of bitstreams: 1 giansante_rh_me_jabo.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5) Previous issue date: 2017-11-27
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Rizobactérias são excelentes candidatas à aplicação em processos de bioacumulação de elementos potencialmente tóxicos, pois desenvolveram mecanismos para a incorporação intracelular de uma ampla gama de íons. A sensibilidade e a capacidade de remoção de cádmio (Cd2+) de duas espécies de rizobactérias: Rizobium tropici (LBMP-C01) e Ensifer meliloti (LBMPC02), foram estudadas. A concentração mínima inibitória (CMI) das bactérias foi determinada pelo cultivo em meio contendo CdCl2.2H2O (0,025 a 4 mmol L-1). Foram realizados testes de viabilidade das células das duas estirpes na CMI e ensaios de bioacumulação com suspensões de células bacterianas nas doses de 10, 20 e 30 %(v/v) em solução contendo 100 mg L-1 de Cd2+. As estirpes LBMP-C01 e LBMP-C02 foram sensíveis a concentrações de Cd2+ superiores a 1,0 e 0,05 mmol L-1, respectivamente. As células de LBMP-C01 e LBMP-C02 apresentaram-se viáveis nas CMI 1,0 e 0,05 mmol L-1 Cd2+, respectivamente. A estirpe LBMP-C01 não removeu Cd2+ nos ensaios de bioacumulação e a estirpe LBMP-C02 foi capaz de remover 80 % deste íon em solução contendo 100 mg L-1 Cd2+, após 72 h de contato e 30 %(v/v) do bioacumulador. Os espectros de absorção molecular na região do infravermelho, de ambas as espécies estudadas praticamente não indicaram diferenças nos grupos funcionais presentes nas moléculas da biomassa celular. A observação por microscopia eletrônica de transmissão mostrou a presença de maior número de grânulos eletrodensos no citoplasma da estirpe de LBMP-C02 em relação à LBMP-C01 quando estas foram cultivadas com Cd2+. A estirpe LBMP-C02 foi a mais eficiente na remoção de Cd2+. A resistência a metais dessas duas bactérias envolve mecanismos diferentes.
Rhizobacteria are excellent candidates for use in the processes of bioaccumulation of potentially toxic elements because they have developed mechanisms for the intracellular uptake of a wide range of ions. Here, the sensitivity and capacity to remove cadmium (Cd2+) of two species of rhizobacteria, Rhizobium tropici (LBMP-C01) and Ensifer meliloti (LBMP-C02), were studied. The minimum inhibitory concentration (MIC) of the bacteria was determined by culturing them in medium containing CdCl2·2H2O (0.025 to 4 mmol L-1 ). Cell viability tests of the two strains were performed at MIC, and bioaccumulation assays were performed with 10, 20, and 30 %(v/v) bacterial cell suspensions in a Cd2+ solution 100 mg L-1 . Strains LBMP-C01 and LBMP-C02 were sensitive to Cd2+ concentrations above 1.0 and 0.05 mmol L-1 , respectively. LBMP-C01 and LBMP-C02 cells were viable at the MICs of Cd2+ solution 1.0 and 0.05 mmol L-1 , respectively. LBMP-C01 did not remove Cd2+ in the bioaccumulation assays, whereas LBMP-C02 removed 80 % of this ion in Cd2+ solution 100 mg L-1 , after 72 h of contact and 30 %(v/v) of the bioaccumulator. The infrared absorption spectra of both species did not indicate differences in the functional groups present in the molecules of the cell biomass. Transmission electron microscopy showed the presence of a larger number of electron-dense granules in the cytoplasm of LBMP-C02 compared to LBMP-C01 when they were cultured with Cd2+. The LBMP-C02 strain was the most efficient in the Cd2+ removal. The metal resistance of these two bacteria involves different mechanisms.

APA, Harvard, Vancouver, ISO, and other styles

8

Lenkutytė, Kristina. "Vario ir kadmio tarpusavio sąveika ir šių sunkiųjų metalų poveikis vasarinių miežių (Hordeum vulgare L. Nutans) augimui." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120620_140104-99231.

Full text

Abstract:

Šis tiriamasis darbas buvo atliekamas norint ištirti vario ir kadmio keliamą poveikį vasarinių miežių (Hordeum vulgare L.) morfologiniams ir fiziologiniams rodikliams bei nustatyti Cu ir Cd bioakumuliaciją šiuose augaluose. Sunkieji metalai veikė augalus pavieniui ir sąveikaudami mišinyje. Tiriami augalai buvo 5 dienas auginami mitybinėje terpėje su skirtingomis vario ir kadmio koncentracijomis (Cu ir Cd pavieniui: 0,1 mg/l, 1 mg/l, 5 mg/l, 10 mg/l ir 100 mg/l bei šių sunkiųjų metalų mišinys: 0,1 mg Cu/l+0,1 mg Cd/l, 1 mg Cu/l+1 mg Cd/l, 5 mg Cu/l+5 mg Cd/l, 10 mg Cu/l+10 mg Cd/l ir 100 mg Cu/l+100 mg Cd/l). Buvo nustatinėti šie parametrai: daigelių aukštis, šaknelių ilgis, stiebelių ir šaknelių biomasė, fotosintezės pigmentų kiekis, malono dialdehido kiekis, vario ir kadmio bioakumuliacija vasarinio miežio lapuose ir šaknyse. Tik esant mažiausiai sunkiųjų metalų koncentracijai stiebelių aukščiai ir šaknelių ilgiai yra didesni arba beveik lygūs kontroliniam variantui (p>0,05), tačiau visos kitos vario ir kadmio koncentracijos nuo 1 mg/l statistiškai patikimai (p<0,05) sumažino stiebų ir šaknų augimą. Esant mažiausiai 0,1 mg/l metalų koncentracijai daigų ir šaknų sausoji biomasė buvo (p>0,05) didesnė arba mažesnė nei kontrolės ir sudarė 96 % - 120 % kontrolės lygio. Esant didesnėms sunkiųjų metalų koncentracijoms daigų ir šaknų biomasės sumažėjo (Cd – p>0,05, Cu – p<0,05) ir sudarė 16 % - 90 % kontrolės lygio. Karotinoidų kiekio padidėjimas nustatytas iki 115 % (100 mg Cd/l) –... [toliau žr. visą tekstą]
This study was conducted to investigate the copper and cadmium effects on spring barley (Hordeum vulgare L.) for morphological and physiological parameters and to determine bioaccumulation of Cu and Cd in these plants. Heavy metal effects on plants alone and synergistically in combination. Test plants were grown for 5 days the culture medium containing different concentrations of copper and cadmium (Cd and Cu alone: 0,1 mg/ l, 1 mg/ l, 5 mg/ l, 10 mg/ l and 100 mg/ l, and these heavy metals mixture of 0,1 mg Cu/ l +0,1 mg Cd/ l, 1 mg Cu/ l +1 mg Cd/ l, 5 mg Cu/ l +5 mg Cd/ l, 10 mg Cu / l +10 mg Cd / l and 100 mg Cu/ l +100 mg Cd/ l). The determination of these parameters sprouts height, root length, stem and root biomass, photosynthetic pigments, and a pleasure dialdehyde formed amount of copper and cadmium bioaccumulation of barley leaves and roots. Only at the lowest concentrations of heavy metals in stem height and root length is larger than or nearly equal to the control variant (p>0,05), but all the other copper and cadmium concentration of 1 mg/ l, statistically significant (p<0,05) reduced the stems and root growth. At least 0,1 mg/ l, the concentration of metals in shoot and root dry biomass was (p<0,05) higher or lower than the control was 96% - 120% of control levels. At higher concentrations of heavy metals in shoot and root biomass decreased (Cd - p>0,05, Cu - p<0,05) and accounted for 16% - 90% of control levels. Carotenoid content was determined by 115 % (100... [to full text]

APA, Harvard, Vancouver, ISO, and other styles

9

Zhou, Hai Yun. "Evaluation of organochlorines and heavy metals in the Pearl River Delta and Hong Kong, with emphasis on bioaccumulation in freshwater fish." HKBU Institutional Repository, 1999. http://repository.hkbu.edu.hk/etd_ra/207.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Sauliutė, Gintarė. "Sunkiųjų metalų kaupimosi lašišų Salmo salar l. audiniuose eksperimentiniai tyrimai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130619_131018-63094.

Full text

Abstract:

Baigiamajame magistro darbe nagrinėjamas sunkiųjų metalų (toliau – SM) keliamas pavojus biotinei ir abiotinei aplinkai, vertinamas eksperimento aktualumas, užsienio šalių bei Lietuvos patirtis šioje srityje. Darbo tikslas – nustatyti SM (Cu, Zn, Ni, Cr, Pb, Cd, Pb) mišinio kaupimosi dėsningumus atlantinių lašišų Salmo salar L. audiniuose (inkstuose, žiaunose, raumenyse, kepenyse) eksperimentinėmis sąlygomis. Gauti rezultatai palyginami su ankstesniųjų metų tyrimų duomenimis, kur analogiškomis bandymo sąlygomis buvo tirtos penkios žuvų rūšys. Nustatyta, kad skirtingos žuvų rūšys skirtingai kaupia SM audiniuose. Lašišoje SM kaupėsi tokia mažėjančia seka: raumenys > žiaunos > inkstai > kepenys. Nustatyti Ni DLK viršijimai raumenyse ir žiaunose, o Pb leistinas kiekis viršytas net 3 audiniuose: raumenyse, žiaunose ir kepenyse. Parengto matematinio modeliavimo rezultatai parodė, kad SM kaupimasis lašišų audiniuose yra specifinis metalui ir audiniui, t. y., skirtingi audiniai parodė skirtingą gebėjimą kaupti SM. Darbo pabaigoje pateikiamos išvados ir rekomendacijos. Darbą sudaro 6 dalys: įvadas, literatūros apžvalga, metodikos aprašymas ir rezultatų analizė, matematinis modeliavimas, išvados ir rekomendacijos, literatūros sąrašas. Darbo apimtis – 90 p., 48 iliustr., 16 lent., 73 bibliografiniai šaltiniai.
The final master thesis discusses potential risks of heavy metals (hereinafter referred to as HM) to theLeopoldas biotic and abiotic environment, relevance of the experimental investigation, Raimondas Idzelis experience of Lithuania and foreign countries in this field. Aim of the work is to evaluate the accumulation patterns of heavy metal mixture (Cu, Zn, Ni, Cr, Pb, Cd) in the tissues of Atlantic salmon Salmo salar L. (kidneys, gills, muscles, liver) in experimental conditions. Results of the work are compared with previous studies, where five species were investigated in the same conditions. It was found that different species accumulate different amounts of HM in the tissues. Salmon accumulate HM in the following descending order: muscles > gills > kidneys > liver. Maximum permissible amount of Ni was exceeded in muscles and gills, while amount of Pb was exceeded even in the three tissues: muscles, gills and liver. Results of the mathematical model showed that the HM accumulation in salmon is specific for metal and for tissue, i.e. different tissues showed a different ability to accumulate HM. At the end of the work general conclusions and recommendations are presented. Structure: introduction, review of literary sources, description of methodology and analysis of results, mathematical modelling, conclusions and recommendations, references. Thesis consists of: 90 p., 48 pictures, 16 tables, 73 bibliographical entries.

APA, Harvard, Vancouver, ISO, and other styles

11

Kostecka, Alicja A. "Adaptations of Arabidopsis halleri to habitats rich in heavy metals in southern Poland." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10014/document.

Full text

Abstract:

Cette étude a tenté de fournir une meilleure description et compréhension de l'origine et de l'évolution de la tolérance et de la capacité d'accumulation vis-à-vis du zinc dans les populations de l'espèce pseudométallophyte Arabidopsis halleri. La recherche a été réalisée à partir de 15 populations métallicoles (M) et non-métallicoles (NM) du sud de la Pologne. Les analyses physico-chimiques des sols et des plantes ont été effectuées afin de caractériser les habitats et les comportements des individus. Les analyses génétiques ont visé à décrire la structure génétique des populations d'A. halleri et à reconstruire leur histoire par une analyse phylogéographique. Les tests de tolérance et d'accumulation réalisés en conditions contrôlées sur les mêmes individus ont recherché les relations entre ces deux traits. Nous avons observé une variance des propriétés du sol et du comportement des populations plus forte dans les sites M; les 2 types des sites diffèrent de manière significative pour les concentrations en métaux lourds ainsi que pour d'autres paramètres physico-chimiques. L'analyse de la structuration génétique neutre menée à partir de 10 marqueurs nucléaires microsatellites a révélé un regroupement des populations en fonction de leur origine géographique. En outre, pour la première fois, nous avons montré qu'il existe des populations NM fondées à partir de populations M. L'analyse de la structuration génétique sélectionnée menée en conditions contrôlées montre que les populations NM sont moins tolérantes et accumulent significativement plus de Zn que les populations M. En revanche aucune relation entre ces traits n'a pu être détectée au niveau des individus eux mêmes
This study attempted to provide a better description and understanding of the origin and the evolution of Zn tolerance and accumulation ability in Arabidopsis halleri populations from southern Poland. The research was carried out on 15 populations from both metalliferous (M) and non-metalliferous (NM) sites. Physic-chemical analyses of field soil and plant samples were performed in order to characterize A. halleri habitats and plants' behavior. Genetic analyses aimed to resolve genetic structure and to reconstruct phylogeography of A. halleri populations from investigated area. Tolerance and accumulation tests in controlled conditions aimed to check if relationships between tolerance and accumulation of heavy metals abilities exist in studied species. Variation of soil properties and population behavior within M sites was higher than within NM and both types of sites differed significantly in terms of heavy metal concentration as well as other physic-chemical parameters. The neutral genetic structure assessed with 10 nuclear microsatellite markers showed that populations were clustered according to their geographic location. Moreover, for the first time it was shown that NM populations might be founded from M populations. The selected genetic structure assessed in controlled conditions showed that NM populations are less tolerant and accumulated Zn to significantly higher concentration as compared to M populations. Nevertheless no relationship between traits was detected at the level of the plant individuals

APA, Harvard, Vancouver, ISO, and other styles

12

Souza, Jane Enisa Ribeiro Torelli de. "Ictiofauna e bioacumulação de metais pesados na cadeia trófica, Rio Gramame, bacia do Rio Gramame Paraíba." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/4140.

Full text

Abstract:

Made available in DSpace on 2015-04-17T14:55:30Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4168210 bytes, checksum: a11f3130727a4c7d1cce532dea7a0d13 (MD5) Previous issue date: 2013-06-27
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The objective of this study was to determine the fish diversity and the bioaccumulation of heavy metals in the trophic chain of River Gramame in the hydrographic basin of River Gramame, Paraíba. The fish composition was determined by collecting fish from 10 specific areas along the River Gramame, utilizing diversified fishery techniques, during the dry and rainy seasons of 2010 to 2011. The fish collected was transported to the Laboratory of Aquatic Ecology (DSE/CCEN/UFPB), where biometry of fish was carried out (total weight and standard length), to determine the type of growth and condition factor, with a view to compare these parameters in contaminated fish. The food habits of the fish were determined by analyzing the stomach contents using the frequency of occurrence method. This was useful to understand the food chain which served as a base for the study of bioaccumulation of heavy metals in fish. The ecological diversity was determined from the indices of diversity (Shannon-Wiener), equitability (Simpson), similarity (Jaccard) and species richness. The concentrations of heavy metals (Pb, Zn, Cd, Cu) in the fish muscle were quantified by square wave voltammetry (VOQ) in a potentiostat/galvanostat in the Laboratory of Environmental Chemical Studies (DQ/CCEN/UFPB), and total mercury (Hg) by atomic absorption spectrometry with cold vapor (CV AAS) in IPEN/USP/SP. The fish composition of the upstream area showed lower taxa than the downstream area (16 to 26 genera and 17 to 27 species, respectively). The abundant species were, Cichla ocellaris (55.39%±28.96), Metynnis lippincottiannus (20.34%±13.4), Prochilodus brevis (16.63%±11.36) and Hoplias malabaricus (13.33%±7.57), during both seasons of the year. The indices of diversity showed differences between the rainy and dry seasons and the upstream and the downstream areas of the reservoir (H =1.3075; H =1.538), (H =1.6497; H =1.3553), with richness represented (17 to 26 and 18 to 22 species respectively) and a heterogeneous distribution of species (J =0.52269 and J =0.38618 respectively), due to the dominance of C. ocellaris in upstream and of M. lippincottianus in downstream of the reservoir. The growth rate of most of the species analyzed showed young individuals, indicating negative allometric growth. The diet of the species showed little difference, indicating mostly generalist food habits of fish along River Gramame. The principal component analysis (PCA) expressed a tendency in upstream and downstream areas of the reservoir to differ in terms of heavy metal accumulation in the trophic chain. A major contamination of total mercury was registered in the upstream area, while there was lead and zinc contamination in the downstream area of the reservoir. It could be concluded that along River Gramame there is major dominance of exotic species with a low diversity of native species. The feeding habits of the fish species showed a generalist tendency, with more omnivores. High heavy metal concentration was registered in the omnivores, indicating biomagnifications of toxic elements among the studied species.
O presente trabalho teve por objetivo, determinar a diversidade da ictiofauna e a bioacumulação de metais pesados na cadeia trófica do Rio Gramame, Bacia do Rio Gramame, Paraíba. Para isso foi realizada análise da ictiofauna presente, com coletas dos espécimes realizadas em 10 pontos ao longo do Rio Gramame, utilizando diversas artes de pesca, durante as estações de chuva e estiagem de 2010 a 2011. O material coletado foi transportado para o Laboratório de Ecologia Aquática (DSE/CCEN/UFPB), onde foram feitas as análises biométricas dos indivíduos (peso total e comprimento padrão), para determinar o tipo de crescimento e o fator de condição, objetivando a comparação desses parâmetros com a contaminação dos peixes. A dieta alimentar das espécies foi conhecida a partir de análises do conteúdo estomacal pelo método de freqüência de ocorrência, com finalidade de conhecer a teia alimentar, que serviu de base para o estudo da biomagnificação dos metais pesados na ictiofauna. Posteriormente, a diversidade ecológica foi determinada a partir dos índices de diversidade (Shannon-Wiener), Equitabilidade (Simpson), similaridade (Jaccard) e riqueza de espécies. As concentrações dos metais pesados (Pb, Zn, Cd, Cu) no tecido muscular das espécies foram quantificados por voltametria de onda quadrada (VOQ) em um potenciostato/galvanostato no Laboratório de Estudos Químicos Ambientais (DQ/CCEN/UFPB), e o mercúrio total (Hg) por espectrometria de absorção atômica com geração de vapor frio (CV AAS) no IPEN/USP/SP. A composição da ictiofauna a montante apresentou um número de taxa menor do que a jusante do reservatório (16 e 26 gêneros e 17 e 27 espécies, respectivamente), sendo as espécies mais abundantes, Cichla ocellaris (55,39%±28,96), Metynnis lippincottiannus (20,34%±13,4), Prochilodus brevis (16,63%±11,36) e Hoplias malabaricus (13,33%±7,57), em ambas as estações do ano. Os índices de diversidade apresentaram diferenças entre as estações de chuva e estiagem e as áreas a montante e a jusante do reservatório (H =1,3075; H =1,538), (H =1,6497; H =1,3553), como uma riqueza representada (17 e 26 e 18 e 22 espécies respectivamente) e uma distribuição heterogênea das espécies (J =0,52269 e J =0,38618 respectivamente), devido à dominância de C. ocellaris a montante e de M. lippincottianus a jusante do reservatório. A estrutura de crescimento da maioria das espécies analisadas foi representada por indivíduos jovens, revelando um crescimento do tipo alométrico negativo na população. A dieta alimentar das espécies apresentou-se pouco diferenciada, levando a uma maior incidência de hábitos alimentares generalistas ao longo do Rio Gramame. A análise de componentes principais (PCA) expressou uma tendência das áreas a montante e a jusante do reservatório diferir quanto à acumulação por metais pesados na cadeia trófica. A maior contaminação por mercúrio total foi registrada a montante, enquanto que, chumbo e zinco a jusante do reservatório. Concluí-se que, ao longo do Rio Gramame a ictiofauna apresentou uma maior dominância de espécies exóticas, levando a uma menor representação na diversidade das espécies nativas. A dieta alimentar das espécies revelou hábitos alimentares generalistas, com a categoria trófica onívora mais abundante. As maiores concentrações dos metais pesados foram registradas entre espécies de hábitos onívoros, indicando uma biomagnificação dos elementos tóxicos entre as espécies estudadas.

APA, Harvard, Vancouver, ISO, and other styles

13

Qin, Yanyan. "Health risk assessment of POPs and heavy metals in Hong Kong residents based on their concentrations in selected food items and different human tissues (blood plasma and adipose tissues)." HKBU Institutional Repository, 2010. http://repository.hkbu.edu.hk/etd_ra/1234.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Palmeira, Ana Rita Onodera. "Ictiofauna e bioacumulação de metais pesados na cadeia trófica, Rio Gramame, Bacia do Rio Gramame Paraíba." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/4139.

Full text

Abstract:

Made available in DSpace on 2015-04-17T14:55:30Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4168210 bytes, checksum: a11f3130727a4c7d1cce532dea7a0d13 (MD5) Previous issue date: 2013-06-27
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The objective of this study was to determine the fish diversity and the bioaccumulation of heavy metals in the trophic chain of River Gramame in the hydrographic basin of River Gramame, Paraíba. The fish composition was determined by collecting fish from 10 specific areas along the River Gramame, utilizing diversified fishery techniques, during the dry and rainy seasons of 2010 to 2011. The fish collected was transported to the Laboratory of Aquatic Ecology (DSE/CCEN/UFPB), where biometry of fish was carried out (total weight and standard length), to determine the type of growth and condition factor, with a view to compare these parameters in contaminated fish. The food habits of the fish were determined by analyzing the stomach contents using the frequency of occurrence method. This was useful to understand the food chain which served as a base for the study of bioaccumulation of heavy metals in fish. The ecological diversity was determined from the indices of diversity (Shannon-Wiener), equitability (Simpson), similarity (Jaccard) and species richness. The concentrations of heavy metals (Pb, Zn, Cd, Cu) in the fish muscle were quantified by square wave voltammetry (VOQ) in a potentiostat/galvanostat in the Laboratory of Environmental Chemical Studies (DQ/CCEN/UFPB), and total mercury (Hg) by atomic absorption spectrometry with cold vapor (CV AAS) in IPEN/USP/SP. The fish composition of the upstream area showed lower taxa than the downstream area (16 to 26 genera and 17 to 27 species, respectively). The abundant species were, Cichla ocellaris (55.39%±28.96), Metynnis lippincottiannus (20.34%±13.4), Prochilodus brevis (16.63%±11.36) and Hoplias malabaricus (13.33%±7.57), during both seasons of the year. The indices of diversity showed differences between the rainy and dry seasons and the upstream and the downstream areas of the reservoir (H =1.3075; H =1.538), (H =1.6497; H =1.3553), with richness represented (17 to 26 and 18 to 22 species respectively) and a heterogeneous distribution of species (J =0.52269 and J =0.38618 respectively), due to the dominance of C. ocellaris in upstream and of M. lippincottianus in downstream of the reservoir. The growth rate of most of the species analyzed showed young individuals, indicating negative allometric growth. The diet of the species showed little difference, indicating mostly generalist food habits of fish along River Gramame. The principal component analysis (PCA) expressed a tendency in upstream and downstream areas of the reservoir to differ in terms of heavy metal accumulation in the trophic chain. A major contamination of total mercury was registered in the upstream area, while there was lead and zinc contamination in the downstream area of the reservoir. It could be concluded that along River Gramame there is major dominance of exotic species with a low diversity of native species. The feeding habits of the fish species showed a generalist tendency, with more omnivores. High heavy metal concentration was registered in the omnivores, indicating biomagnifications of toxic elements among the studied species.
O presente trabalho teve por objetivo, determinar a diversidade da ictiofauna e a bioacumulação de metais pesados na cadeia trófica do Rio Gramame, Bacia do Rio Gramame, Paraíba. Para isso foi realizada análise da ictiofauna presente, com coletas dos espécimes realizadas em 10 pontos ao longo do Rio Gramame, utilizando diversas artes de pesca, durante as estações de chuva e estiagem de 2010 a 2011. O material coletado foi transportado para o Laboratório de Ecologia Aquática (DSE/CCEN/UFPB), onde foram feitas as análises biométricas dos indivíduos (peso total e comprimento padrão), para determinar o tipo de crescimento e o fator de condição, objetivando a comparação desses parâmetros com a contaminação dos peixes. A dieta alimentar das espécies foi conhecida a partir de análises do conteúdo estomacal pelo método de freqüência de ocorrência, com finalidade de conhecer a teia alimentar, que serviu de base para o estudo da biomagnificação dos metais pesados na ictiofauna. Posteriormente, a diversidade ecológica foi determinada a partir dos índices de diversidade (Shannon-Wiener), Equitabilidade (Simpson), similaridade (Jaccard) e riqueza de espécies. As concentrações dos metais pesados (Pb, Zn, Cd, Cu) no tecido muscular das espécies foram quantificados por voltametria de onda quadrada (VOQ) em um potenciostato/galvanostato no Laboratório de Estudos Químicos Ambientais (DQ/CCEN/UFPB), e o mercúrio total (Hg) por espectrometria de absorção atômica com geração de vapor frio (CV AAS) no IPEN/USP/SP. A composição da ictiofauna a montante apresentou um número de taxa menor do que a jusante do reservatório (16 e 26 gêneros e 17 e 27 espécies, respectivamente), sendo as espécies mais abundantes, Cichla ocellaris (55,39%±28,96), Metynnis lippincottiannus (20,34%±13,4), Prochilodus brevis (16,63%±11,36) e Hoplias malabaricus (13,33%±7,57), em ambas as estações do ano. Os índices de diversidade apresentaram diferenças entre as estações de chuva e estiagem e as áreas a montante e a jusante do reservatório (H =1,3075; H =1,538), (H =1,6497; H =1,3553), como uma riqueza representada (17 e 26 e 18 e 22 espécies respectivamente) e uma distribuição heterogênea das espécies (J =0,52269 e J =0,38618 respectivamente), devido à dominância de C. ocellaris a montante e de M. lippincottianus a jusante do reservatório. A estrutura de crescimento da maioria das espécies analisadas foi representada por indivíduos jovens, revelando um crescimento do tipo alométrico negativo na população. A dieta alimentar das espécies apresentou-se pouco diferenciada, levando a uma maior incidência de hábitos alimentares generalistas ao longo do Rio Gramame. A análise de componentes principais (PCA) expressou uma tendência das áreas a montante e a jusante do reservatório diferir quanto à acumulação por metais pesados na cadeia trófica. A maior contaminação por mercúrio total foi registrada a montante, enquanto que, chumbo e zinco a jusante do reservatório. Concluí-se que, ao longo do Rio Gramame a ictiofauna apresentou uma maior dominância de espécies exóticas, levando a uma menor representação na diversidade das espécies nativas. A dieta alimentar das espécies revelou hábitos alimentares generalistas, com a categoria trófica onívora mais abundante. As maiores concentrações dos metais pesados foram registradas entre espécies de hábitos onívoros, indicando uma biomagnificação dos elementos tóxicos entre as espécies estudadas.

APA, Harvard, Vancouver, ISO, and other styles

15

Phuong, Tran Thi Mai. "Bioaccumulations des métaux lourds dans la baie de Nha Trang, Khanh Hoa, Viet Nam." Thesis, Nice, 2014. http://www.theses.fr/2014NICE4058/document.

Full text

Abstract:

L'étude sur le potentiel de bioaccumulation des mollusques comme bioindicateur est un effort important à appliquer rigoureusement dans les régions tropicales. Cette thèse présente les résultats de notre enquête pendant deux ans (2012-2013) dans 4 sites côtiers de la baie de Nha Trang de la province de Khanh Hoa (Viet Nam). L'étude a utilise des méthodes d'analyse appropriées pour déterminer la pollution en métaux lourds des sédiments et interpréter la capacité de bioaccumulation de ces métaux lourds dans plusieurs types de mollusques pour la proposer des bioindicateur et évaluer les risques lies a la consommation de ces mollusques provient des substances toxiques. Les résultats de cette étude ont démontré que la concentration de métaux lourds comme Cr, Cd, Cu et Zn ne présent pas les effets biologiques. Un traitement des résultats sur le choix d'une espece comme bioindicateurs, y compris Laternula anatine, Glauconome virens, Katelysia hiantina et Geloina coaxans en terme de bioaccumulation BSAF de métal dans leurs tissus. Les facteurs de bioaccumulation conduisant au choix d'un espèce particulière, la quelle K.hiantina pourrait être le meilleur indicateur de la pollution par les métaux
The study on the potential bioaccumulation of mollusks as bioindicator is an important effort that contributes to the findings of method in monitoring pollution in an environment of tropical regions. This thesis reports the results of our investigation of heavy metals in mollusks and sediment samples collected from four coastal sites of different environmentally background in Nha Trang bay and adjacent areas, Khanh Hoa province, Viet Nam during 2 years from 2012 to 2013. The study used suitable analyzing methods update to find the bioaccumulation capacity of trace metals in marine ecosystems, evaluation of the bioavailability of potentially toxic substances on human health risks and available for predicting the environmental fat and effects of pollutions. Results from this study demonstrated that the 5 metals As, Cr, Cd, Cu and Zn concentrations of sediments were acceptable or moderate biological effects. These studied mollusk species including Laternula anatine, Glauconome virens, Katelysia hiantina and Geloina coaxans have high potential factors in term of metal BSAF in their tissues. They have served as good bioindicator organisms, in which K.hiantina might be the best indicator of metal pollution as it is high presence, abundance and wide geographical distribution in the study area

APA, Harvard, Vancouver, ISO, and other styles

16

Kadiene, Esther Uzoma. "Effect of heavy metal toxicity on calanoid copepods : experimental approach." Thesis, Lille, 2019. http://www.theses.fr/2019LIL1R017.

Full text

Abstract:

Cette thèse cible les facteurs biotiques qui influent sur la toxicité des métaux chez les copépodes calanoïdes. Tout d'abord, la toxicité du cadmium (Cd) entre deux copépodes de l'ordre; calanoida Eurytemora affinis (Poppe 1880) d'une région tempérée (estuaire de la Seine, France) et Pseudodiaptomus annandalei (Sewell 1919) d'une région subtropicale (estuaire de Danshuei, Taiwan), ont été déterminés sur la base de leur sexe et de leur état de reproduction. Les résultats de cette étude ont révélé que les deux copépodes avaient des niveaux de sensibilité différents à la toxicité du cadmium et que leur sensibilité au cadmium était également fortement dépendante de leur sexe et de leur état de reproduction. En outre, une étude de la toxicité du cadmium dans les traits de vie du copépode a été testée en utilisant P. annandalei comme espèce modèle. Les résultats ont révélé que la toxicité du cadmium était également dépendante du stade de développement des copépodes. De plus, le Cd a eu un effet négatif sur la croissance, la reproduction et la durée de vie du copépode. Afin de comprendre la raison de la sensibilité au cadmium spécifique au sexe, la bioaccumulation du cadmium chez les deux sexes a été réalisée. De plus, dans les environnements naturels, les copépodes peuvent bioaccumuler les métaux via une voie directe dans l’eau ou via les aliments consommés. Dans un premier temps, des essais préliminaires ont été effectués pour identifier la cinétique de bioaccumulation des métaux chez les micro-algues utlisées pour nourrir les copépodes. L'accumulation du Cd dans les microalgues a été testée en exposant Pavlova lutheri dans différentes conditions de salinité et température. À la fin, il a été observé que l’augmentation de la température et la faible salinité favorisent l’absorption de Cd par les micro-algues. P. annandalei a ensuite été exposé au cadmium dans l'eau et par le biais de son régime alimentaire, en utilisant les informations fournies par les résultats ci-dessus. Cette expérience a révélé que l'absorption de Cd par P. annandalei provenait nettement plus d'eau que de la nourriture. Une hypothèse a été développée sur les raisons pour lesquelles l'absorption de Cd par l'eau par les copépodes était plus élevée que par l'exposition par Cd via l’aliment. En d’autres termes, l’absorption de métaux par l’eau est une voie plus importante dans la bioaccumulation des métaux que par la voie alimentaire en raison de l’absorption orale. L'hypothèse a été démontrée en exposant les copépodes à un colorant alimentaire et, à l'aide d'un microscope, il a été constaté que le colorant était entré dans l'intestin du copépode par l'ouverture de la bouche. L'absorption orale d'eau par le copépode a été confirmée par un test de bioaccumulation. Une étude moléculaire sur le test transcriptomique et l'expression différentielle spécifique au sexe du copépode de P. annandalei exposé au Cd a été réalisée. Les résultats ont montré que les copépodes de P. annandalei répondaient à la toxicité du cadmium de manière spécifique au sexe, et expliquaient pourquoi la femelle était moins sensible au cadmium que les copépodes mâles. De plus, l'exposition multigénérationnelle de P. annandalei au cadmium a montré un développement possible de l'adaptation, en particulier chez les copépodes femelles. Bien que les copépodes puissent développer des mécanismes adaptatifs pour tolérer les produits chimiques toxiques, une concentration croissante de métaux dans le milieu aquatique ainsi que des transferts de métaux par la mère sur plusieurs générations pourraient augmenter la concentration de copépodes. Une exposition à long terme pourrait réduire leur forme, compromettant ainsi la structure de la population de copépodes. Cette étude a montré que la mortalité, les traits d'histoire de vie et les réponses moléculaires des espèces modèles peuvent fournir d'importants bioindicateurs pour l'évaluation des risques environnementaux
As a result of the growing concerns about the fate of copepod ecology in the face of increasing environmental pollutants, several studies are being carried out. This thesis focused on biotic factors that influences metal toxicity in calanoid copepods. Firstly, cadmium (Cd) toxicity between two copepods in the order; calanoida; Eurytemora affinis (Poppe 1880) from a temperate region (Seine Estuary, France) and Pseudodiaptomus annandalei (Sewell 1919) from a subtropical region (Danshuei Estuary, Taiwan), was determined based on their sex and reproductive states. Results from this investigation revealed that both copepods have different levels of sensitivity to cadmium toxicity and also, their sensitivity to cadmium was significantly dependent on their sexes and reproductive states. In addition, an investigation of cadmium toxicity in copepod life history traits were further tested using P. annandalei as a model specie. The results revealed that Cd toxicity was also dependent on the developmental stages of the copepods. In addition, Cd showed negative effect on the growth, reproduction and lifespan of the copepod. Furthermore, to understand the reason for sex-specific sensitivity to cadmium, an investigation on the bioaccumulation of Cd was carried out. Moreover, in the natural environments, copepods could bioaccumulate metals either directly from the water or indirectly from consumed diets. Before, both routes of metal uptake were tested, some preliminary test was carried out on the rate at which copepod diet (microalgae) take up metal. Microalgae accumulation of Cd was tested by exposing Pavlova lutheri to Cd under different conditions (salinity and temperature). At the end, it was observed that increased temperature and low salinity influenced the uptake of Cd in the algae. P. annandalei was then exposed to Cd in water and through their diets, using the information from the above results. This investigation revealed that P. annandalei uptake of Cd was significantly more from water than from the diets. A hypothesis was developed based on why copepod uptake of Cd from water was higher than from dietary Cd exposure. That is, metal uptake from water is a more important route in the bioaccumulation of metals than through dietary route because of oral intake. The hypothesis was demonstrated by exposing copepods to a dyed medium, and with the aid of a microscope, the dyed medium was observed to have entered inside the gut of the copepod through the mouth opening. Oral intake of water by copepod was confirmed by a bioaccumulation test. A molecular study on the transcriptomic assay and sex-specific differential expression of P. annandalei copepod exposed to Cd was carried out. The results showed that P. annandalei copepod responded to Cd toxicity in a sex-specific manner, and why female was less sensitive to Cd than male copepods were discussed. Moreover, multigenerational exposure of P. annandalei to Cd showed a possible development of adaptation, particularly in the female copepods. Although, copepods could develop adaptive mechanisms to tolerate toxic chemicals, however, an increasing concentration of metals in the aquatic environment in addition to maternal transfers of metals over several generations could increase the concentration in copepods. A long term exposure could reduce their fitness, thereby compromising copepod population structure. This study showed that mortality, life history traits and molecular responses of model species can provide important bio-indicators for environmental risk assessment

APA, Harvard, Vancouver, ISO, and other styles

17

LeCoultre, Trent David. "A meta-analysis and risk assessment of heavy metal uptake in common garden vegetables." [Johnson City, Tenn. : East Tennessee State University], 2001. http://etd-submit.etsu.edu/etd/theses/available/etd-1107101-131704/unrestricted/LeCoultret112101a.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Kerkhoff, Sabrina. "Dinâmica do mercúrio na estrutura do ecossistema do reservatório da Usina Hidrelétrica de Itaipu." Universidade Estadual do Oeste do Parana, 2016. http://tede.unioeste.br:8080/tede/handle/tede/1826.

Full text

Abstract:

Made available in DSpace on 2017-07-10T18:01:59Z (GMT). No. of bitstreams: 1 Sabrina Kerkhoff.pdf: 1356544 bytes, checksum: df7e0e05534fa8cbacb0d1339f0ad345 (MD5) Previous issue date: 2016-04-05
In recent decades the intensive development of economic activities and population growth resulted in greater pressure on aquatic ecosystems. And among the various forms of environmental contamination, pollution by metals such as mercury (Hg) stands out as one of the cause of concern for government researchers and agencies, as it can result in health problems, as a teratogenic agent and affect the central nervous system, furthermore, should be considered the environmental and economic effects. Based on this problem this research objectified to study the dynamics of Hg in the structure of the aquatic ecosystem of the Itaipu reservoir representative compartments of the trophic chain of this reservoir in order to preliminarily analyze the occurrence of biomagnification process in the trophic chain. The hypothesis was that the Hg presents different concentrations in different compartments and the concentration gradient obeys the same direction of flow of the food chain in aquatic ecosystem structure. Samples were collected in the months of December/2014, May and August/2015 in an arm of the Itaipu reservoir, located in São Miguel do Iguaçu, Brazil, covering three points. The compartments analyzed for total Hg were the sediment, phytoplankton, zooplankton, zoobenthos and fish community, including three species of different eating habits, they being the Hypophtalmus edentatus (slicer), Pterodoras granulosus (omnivorous) and Cichla monoculus (piscívoro). Total Hg analyzes were performed by atomic absorption spectrophotometry a variance analysis (ANOVA) nonparametric was conducted to determine if there were differences in mercury concentration of the different components of the ecosystem. The results showed significant differences among the groups with the largest total Hg concentrations detected for phytoplankton (145,08 ng.g-1 ± 83.77), followed by zooplankton (87,62 ng.g-1 ± 25,58), zoobenthos (32.59 ng.g-1 ± 40,56), sediment (8.69 ng.g-1 ± 3,12) and fish (1,59 ± 1.48 ng.g-1 ). In the fish compartment, the highest concentrations were observed for the filtrador habit (H. edentatus) with 3,2 ng.g-1, followed by piscivorous species (C. monoculus) with 0,95 ng.g-1 and omnivorous (P. granulosus) 0,35 ng.g-1. It was detected significant relationship between the standard length and total Hg concentrations for the species analyzed. Preliminary analysis when the Biomagnification process showed that higher concentrations of total Hg in the food chain base compartments (phytoplankton), and the lowest concentrations of total Hg chain top bodies (fishes) indicate that probably biogeochemical conditions of this environment are not conducive to methylation and biomagnification of Hg.
Nas últimas décadas o intenso desenvolvimento de atividades econômicas e o crescimento populacional resultaram em uma maior pressão sobre os ecossistemas aquáticos. E entre as várias formas de contaminação do ambiente, a poluição por metais como o mercúrio (Hg) destaca-se como uma das fontes de preocupação para pesquisadores e órgãos governamentais, visto que pode resultar em problemas de saúde pública, por ser um agente teratogênico e afetar o sistema nervoso central, além disso, devem ser considerados os efeitos ambientais e econômicos. Baseado nesta problemática esta pesquisa objetivou estudar a dinâmica do Hg na estrutura do ecossistema aquático do reservatório de Itaipu em compartimentos representativos da cadeia trófica deste reservatório, a fim de analisar preliminarmente a ocorrência do processo de biomagnificação na cadeia trófica. A hipótese era que o Hg apresenta concentrações distintas nos diversos compartimentos e que o gradiente de concentração obedece ao mesmo sentido do fluxo da cadeia trófica na estrutura do ecossistema aquático. As amostragens foram realizadas nos meses de dezembro/2014, maio e agosto/2015, em um braço do reservatório de Itaipu, situado na cidade de São Miguel do Iguaçu (PR), contemplando três pontos. Os compartimentos analisados quanto ao Hg total foram o sedimento, fitoplâncton, zooplâncton, zoobentos e comunidade íctica, abrangendo três espécies de hábitos alimentares diferentes, sendo elas o Hypophthalmus edentatus (filtrador), o Pterodoras granulosus (onívoro) e o Cichla monoculus (piscívoro). As análises de Hg total foram realizadas por espectrofotometria de absorção atômica, foi realizada uma análise de variâncias (ANOVA) não paramétrica, para determinar se havia diferença na concentração de mercúrio dos diferentes componentes do ecossistema. Os resultados apontaram diferenças significativas entre os grupos analisados, sendo as maiores concentrações de Hg total detectadas para o fitoplâncton (145,08 ng.g-1 ± 83,77), seguido do zooplâncton (87,62 ng.g-1 ± 25,58), zoobentos (32,59 ng.g-1 ± 40,56), sedimento (8,69 ng.g-1 ± 3,12) e peixes (1,59 ng.g-1 ± 1,48). No compartimento peixes, as maiores concentrações foram observadas para o de hábito filtrador (H. edentatus) com 3,2 ng.g-1, sendo seguido pela espécie piscívora (C. monoculus) com 0,95 ng.g-1 e onívora (P. granulosus) com 0,35 ng.g-1. Não foi detectada relação significativa entre o comprimento padrão e as concentrações de Hg total para as espécies analisadas. A análise preliminar quando ao processo de biomagnificação demonstrou que as concentrações mais elevadas de Hg total em compartimentos de base de cadeia alimentar (fitoplâncton) e as concentrações mais baixas de Hg total em organismos topo de cadeia (peixes) indicam que provavelmente as condições biogeoquímicas deste ambiente não sejam propicias à metilação e biomagnificação do Hg.

APA, Harvard, Vancouver, ISO, and other styles

19

Wintle, Nathan J. "Total Mercury in Stranded Marine Mammals from the Oregon and Southern Washington Coasts." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/310.

Full text

Abstract:

Muscle samples from 105 marine mammals stranded along the Oregon-Washington coasts (2002-2009) were tested for levels of total mercury by Cold Vapor Atomic Fluorescence Spectrometry. The total mercury present is predominantly in the form of highly toxic methylmercury. After normalizing muscle tissue to 75% water weight, due to variance in water content, Steller sea lions (Eumetopias jubatus) and northern elephant seals (Mirounga angustirostris) exhibited the highest mean concentrations of total mercury followed by harbor seals (Phoca vitulina), harbor porpoises (Phocoena phocoena), and California sea lions (Zalophus californianus); 0.34 ± 0.278, 0.34 ± 0.485, 0.21 ± 0.216, 0.17 ± 0.169 and 0.15 ± 0.126 mg/kg normalized weight, respectively. Mean normalized values demonstrated limited muscle methylmercury accumulation in these species in the Pacific Northwest. Normalizing muscle mercury concentrations eliminated variability from desiccation, and allowed for a clearer indication of the amount of mercury the animal accumulated before stranding. However, actual wet weight concentrations in some of the stranded carcasses were high enough to pose a risk to scavengers.

APA, Harvard, Vancouver, ISO, and other styles

20

Šindelářová, Anna. "Analýza zubů a kostí metodou spektroskopie laserem buzeného plazmatu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-445149.

Full text

Abstract:

The presented diploma thesis deals with the elemental composition of hard tissues – human and murine jaws studied by laser-induced plasma spectroscopy (LIBS). Samples of human teeth contained a disease called ankylosis and the difference in elemental composition of healthy and diseased tissue was observed to localize ankylosis in the tooth. When evaluating the map of the spatial distribution of phosphorus and calcium, a decrease in the concentration of these elements in the ankylosis infected area was observed. Furthermore, murine jaws containing lead were analyzed. When assessing the spatial distribution of lead in tissue, it was found that lead was incorporated in murine teeth in the enamel at the tip of the incisor and molars. In conclusion, LIBS method achieved good results considering the detection of the elemental distribution of hard tissues. It enables to differentiate parts of the tooth in terms of elemental composition and tissue hardness and also to detect changes in the matrix caused by a disease or bioaccumulation of heavy metals.

APA, Harvard, Vancouver, ISO, and other styles

21

Yu, Shuo. "Bioaccumulation of Metals in Earthworms." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259697144.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Marín, Guirao Lázaro. "Aproximación ecotoxicológica a la contaminación por metales pesados en la laguna costera del Mar Menor." Doctoral thesis, Universidad de Murcia, 2007. http://hdl.handle.net/10803/10773.

Full text

Abstract:

El objetivo de la Tesis es obtener una visión de la situación actual de la laguna costera del Mar Menor en relación con la contaminación por metales pesados procedentes de actividades mineras mediante el empleo de herramientas ecotoxicológicas. Comienza con el estudio de la entrada de residuos mineros en el ecosistema, su distribución en las aguas de la laguna así como los efectos tóxicos asociados. Continua valorando la biodisponibilidad de los metales contenidos en los sedimentos lagunares mediante pruebas de toxicidad y de bioacumulación; sus efectos en praderas de fanerógamas y comunidades de invertebrados asociados, para continuar determinando la potencial transferencia trófica de metales en las redes alimenticias lagunares y su posible biomagnificación. Finalmente, la Tesis concluye determinando la utilidad de indicadores propuestos para su aplicación en la Directiva Europea Marco del Agua cuando son aplicados a dos ecosistemas acuáticos contaminados por contaminación tóxica (metales pesados).
The objective of the Thesis is to determine the present situation of the Mar Menor coastal lagoon in relation with the contamination caused by heavy metals coming from old mining activities through the use of ecotoxicological tools. It begins with the study of the entrance of mining wastes in the lagoon ecosystem, its distribution in the lagoon waters as well as their toxic effects. It continues assessing the bioavailability of metals contained in sediments of the lagoon by means of bioaccumulation studies and toxicity tests; their possible deleterious effects on marine phanerogams and associated invertebrate communities. It also determines the potential trophic transfer of metals in trophic webs of the lagoon studying the possible biomagnification of metals. Finally, the Thesis concludes determining the utility of some indicators proposed for their application in the European Water Framework Directive when they are applied to aquatic ecosystems impacted by toxic contamination (heavy metals).

APA, Harvard, Vancouver, ISO, and other styles

23

Kuhn, Sabine Plocher. "Bioaccumulation of metals using immobilized Zoogloea ramigera /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu148759497065045.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Melato, Aupaki Michael. "Bioaccumulation of metals in the Kuils River, Western Cape." Thesis, Cape Peninsula University of Technology, 2011. http://hdl.handle.net/20.500.11838/2013.

Full text

Abstract:

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2011.
World wide urban rivers are the most utilised and degraded. A variety of everyday sources of metal pollution exist that is entrenched in the modern way of life. Lately there has been a tremendous growth in the establishment and development of human settlements, both formal and informal in the Cape Town area. The surroundings of the Kuils River are not excluded from this. There are various communities in close proximity to the Kuils River. Due to this, more industries are also being established. This has caused an increased production of potential environmental pollutants, including metals. The aim of the study was firstly, to identify potential sources of metal pollution along the entire length of the Kuils River, in order to identify sampling sites. Secondly, to identify the metals contaminating the water and sediment of the Kuils River. Thirdly, to determine the bioaccumulation of metals in freshwater snails (Physa ecuta). Four sampling sites were identified along the Kuils River. Freshwater snails (P. acuta), sediment and water were collected every 2 months for a period of one year. The following metals were investigated: Aluminium (AI), Cadmium (Cd) Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Manganese (Mn), Nickel (Ni.) and Zinc (Zn). Samples were digested with 55% nitric acid. The Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES) were used for metal analyses. The results were statistically analysed by means of ANOVA on ranks using the Sigmastat statistical package. Results revealed that most metals found in water, sediment and snails had significantly higher concentrations at site 1. This is possibly due to input from the surrounding urban area and nearly agricultural activities. Water concentrations of AI, Cu, Mn and Zn were higher than the DWAF (1996) guidelines. Sediment was mostly contaminated with AI, Fe, Pb and Zn, while the snails contained significant levels of Cu, Fe, Mn and Zn. Further investigations involving toxicity testing should be conducted to determine the toxicity of these metals to (Physa acuta).

APA, Harvard, Vancouver, ISO, and other styles

25

Oltmanns, Jan. "Biosensors for heavy metals." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/22854.

Full text

Abstract:

Heavy metals from natural and man-made sources can be a great threat to human and animal life. As small inorganic ions they are challenging to detect, usually requiring expensive and complicated machinery. Several heavy metals can accumulate in the human body, leading to long term toxic effects on the nervous system. Many bacteria have developed strategies to survive in heavy metal rich environments. One of these strategies is a bacterial operon containing genes for detoxification mechanisms controlled by a promoter and a regulatory protein. In this work some of these promoter-protein pairs, Pars-ArsR, PcopA-CueR, PmerTPAD-MerR and PzntA-ZntR from Escherichia coli have been employed in the design and construction of a set of biosensors aimed at the detection of heavy metals in drinking water. Biosensors usually employ biological recognition elements, transducing the signal from these to produce an output that can be integrated into electronic circuitry. The sensors presented in this work focus on reducing complexity and on providing a controlled sensor reaction. The arsenic biosensor ‘AsGard’ is based on the Pars-ArsR pair and functions by making the dissociation of an ArsR-mCherry fusion protein from its binding site in the Pars promoter visible. In the cell, ArsR dissociates from Pars upon binding of trivalent arsenic ions. Immobilising the relevant part of the Pars sequence on a solid plastic support allows for the mobilisation of previously bound ArsR-mCherry proteins in the presence of arsenic to become the sensor output. The AsGard sensor detects arsenic within minutes in a concentration range overlapping with the arsenic thresholds for drinking water as set by the World Health Organisation. Additional prototype sensors are presented bringing a reporter gene under the control of the aforementioned promoters. These sensors have been tested in vivo and in vitro in a cell free transcription translation system and partially detect metal concentrations close to relevant ranges. The Pars based sensor is tuneable in vitro by modifying the ratio of the supplied regulatory protein ArsR and is able to detect arsenic well within the relevant range. Spinach2, a fluorescent RNA aptamer, may make future designs independent from translation, drastically reducing complexity of cell free biosensors based on cis-trans transcriptional regulation.

APA, Harvard, Vancouver, ISO, and other styles

26

Szymanski, Nayara. "Estudo da bioacumulação de cobre e chumbo pela macrófita aquática Eicchornia crassipes em solução hidropônica." Universidade Estadual do Oeste do Parana, 2011. http://tede.unioeste.br:8080/tede/handle/tede/1843.

Full text

Abstract:

Made available in DSpace on 2017-07-10T18:08:01Z (GMT). No. of bitstreams: 1 Nayara Szymanski.pdf: 2166541 bytes, checksum: d5ebf09357be44af458b98aeeb5d43bc (MD5) Previous issue date: 2011-02-11
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Aquatic macrophytes are known to remove heavy metals from the surface by adsorption or absorption and incorporate them into systems, in different ways. The main objective of this work is to study the multicomponent bioaccumulation of copper and lead by the living aquatic macrophyte Eicchornia crassipes. The experiments were performed in triplicate using about 30g healthy young plants and 5L Clark s hydroponic solution doped with non-toxic concentration of copper and lead metals combined. All experiments have been carried out in a greenhouse, for 20 days, monitoring the loss of water volume and adding deionized water as it was needed. Samples were performed in predetermined collection times (2, 4, 7, 12 and 20 days) to determined the metal content by the synchrotron radiation reﬂection X-ray ﬂuorescence technique (SR-TXRF), and the measurements of SR-TXRF were performed at the Brazilian Light Synchrotron Laboratory (LNLS). It was observed that at least 90% metal concentration was removed of all experiments by bioaccumulation process, this indicates that the adsorption process is quick in roots, but slow if accumulation process takes place in aerial parts. The kinetics of biosorption that better fits the experimental data was Irreversible Langmuir for Cu and Pb, and Pseudo-first order and Pseudo-second order for Cu and Pb, respectively at the multicomponent experiment.
Macrófitas aquáticas são conhecidas por removerem metais pesados pela superfície, por adsorção ou absorção, e incorporá-los em seu sistema de diversas formas. O objetivo principal deste trabalho é estudar a remoção multicomponente de cobre e chumbo pela macrófita aquática flutuante Eicchornia crassipes viva. Experimentos foram realizados em triplicata, utilizando em média 30 gramas de plantas, jovens e sadias em 5L de solução hidropônica de Clark dosada a uma concentração não tóxica de metais cobre e chumbo em três combinações. Todos os experimentos foram conduzidos em estufa externa, durante 20 dias, monitorando-se o nível do volume de água pela adição de água deionizada quando necessário. Coletas de amostras foram feitas em tempos pré-determinados (2, 4, 7, 12 e 20 dias). A determinação das quantidades de metais foi feita utilizando-se da técnica de espectroscopia de Raios-X por Reflexão Total (SR-TXRF), e as medidas de SR-TXRF foram efetuadas no Laboratório Nacional de Luz Síncrotron (LNLS). Foi observada redução de até 90% nos valores de concentração dos metais, nos experimentos realizados, indicando que cobre e chumbo foram removidos pela macrófita pelo processo de bioacumulação, ou seja, rápida adsorção pelas raízes e um lento processo de acumulação nas partes aéreas. As cinéticas de biossorção que melhor ajustaram-se aos dados experimentais foram de Langmuir Irreversível para Cu e Pb, e de Pseudo-primeira ordem e Pseudo-segunda ordem para Cu e Pb, respectivamente no experimento multicomponente.

APA, Harvard, Vancouver, ISO, and other styles

27

Moore, Margaret Heather. "Feeding and bioaccumulation of trace metals in deep sea holothurians." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241421.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Sörme, Louise. "Urban heavy metals stocks and flows /." Linköping : Univ. : Vatten i natur och samhälle, Institutionen för tema [distributör], 2003. http://www.bibl.liu.se/liupubl/disp/disp2003/arts270s.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Beckett, C. L. "Heavy metals in Severn Estuary ecosystems." Thesis, University of Bristol, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373733.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Limson, Janice. "Aging, sex, death (and heavy metals)." Rhodes University, 2011. http://hdl.handle.net/10962/d1019732.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Xu, Yuping. "Interactions of heavy metals with minerals /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487856076412928.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Figures, Julie Elizabeth. "A study of the biochemistry of selected metals in the Clyde Estuary." Thesis, University of the West of Scotland, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360233.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Cheung, Kai-him Matthew, and 張啟謙. "Bioremediation of toxic metals." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/194562.

Full text

Abstract:

Traditional remediation techniques in removing toxic metal contaminants using physical and chemical methods are expensive and may cause other forms of damage to the environment, comparing with these techniques bioremediation can serve as an inexpensive, effective and environmental friendly remediation method. This thesis mainly discusses different bioremediation techniques and identifies possible areas in Hong Kong for bioremediation and suggests bioremediation methods for each potential area. Bioremediation of toxic metals is the use of microorganisms, plants, or even larger sized organisms to decontaminate sites with toxic metals. Bioremediation includes phytoremediation, microremediation and vermiremediation which use plants, microorganisms and earthworms to remediate contaminated environments respectively. The 4 most common mechanisms in phytoremediation of toxic metals are phytoextraction, phytofiltration, phytovolatilization and phytostabilization. Phytoremediation are used frequently for remediation around the world and its development includes using well-understood technology and genetic engineering to increase its effectiveness. Microremediation is another promising technology in bioremediation of toxic metals and consists of 6 major mechanisms which are biosorption, bioaccumulation, biotransformation, bioleaching, biomineralization and microbially-enhanced chemisorption of metals. Microremediation is mainly in research phase and its development includes identifying new species, combining with phytoremediation and genetic engineering. Vermiremediation is another rapidly developing technique in bioremediation of toxic metals, assisting other bioremediation by burrowing actions of earthworms and its excretion, and accumulating toxic metals inside their bodies. Vermiremediation is also in research phase but it is rapidly developing. Generally, bioremediation is around 60% cheaper than traditional remediation methods and no pollutants are emitted during the process. However the remediation process is slow and generally takes longer than a year. Sources of toxic metals in contaminated areas in Hong Kong are mainly due to historic industrial discharge although present activities also contribute. Potential areas include sites for electronic waste activities, sediments of Kwun Tong typhoon shelter and sediments of Tolo Harbour.
published_or_final_version
Environmental Management
Master
Master of Science in Environmental Management

APA, Harvard, Vancouver, ISO, and other styles

34

Al-Asheh, Sameer. "Sorption of heavy metals by biological materials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq26101.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Warren, Robert Stephen. "Heavy metals in urban street surface sediments." Thesis, Middlesex University, 1987. http://eprints.mdx.ac.uk/13575/.

Full text

Abstract:

A literature survey has been undertaken of the sources, levels and effects of heavy metal pollution in the urban street environment. Established techniques for the determination of heavy metal levels in urban dusts have been reviewed, and appropriate methods selected for use in the research project. Spatial and temporal variations of Cd, Cu, Pb and Zn in street dust have been investigated at a number sites. Metal loadings showed stronger spatial variation than concentrations with the greatest metal loadings occurring in the gutters and kerbsides. The results have been assessed in terms of surface type and condition, traffic loadings and antecedent weather conditions. The chemical associations of heavy metals in street dust, and their relationships to particle size have been investigated. Lead and Zn were associated mainly with carbonates and Fe-Mn oxides, whereas Cu is largely found in the organic fraction. Cadmium shows the greatest affinity for the exchangeable phase, and is therefore considered the most environmentally mobile metal studied. In addition to the studies mentioned above levels and chemical associations of heavy metals In school playground dust contaminated by paint flakes have been investigated. The levels of Pb were much higher than those previously reported. Exchangeable Pb concentrations represented a significant hazard to children playing in the area. In addition to the studies mentioned above levels and chemical associations of heavy metals In school playground dust contaminated by paint flakes have been investigated. The levels of Pb were much higher than those previously reported. Exchangeable Pb concentrations represented a significant hazard to children playing in the area. The final stage of the research project involved the operation of a sampling network to establish a mass balance for Cd, Cu, Pb and Zn within a residential urban street. Metal levels in atmospheric deposition, street sediments and runoff were monitored over an eight week period. Stormwater runoff was found to remove only a minor fraction of the metal deposited in the catchment during the sampling period.

APA, Harvard, Vancouver, ISO, and other styles

36

Agarwal, P. "Magnetism and superconductivity in heavy-fermion metals." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595373.

Full text

Abstract:

One of the key challenges of contemporary condensed matter physics is to understand how the large variety of states of matter arises in electron systems. While the basic force is in all cases the electrostatic Coulomb interaction, the variety of states of matter spans an impressively broad spectrum, ranging from insulators to superconductors, and including a variety of magnetic phases. In recent years, a series of new, emergent phenomena have added more exotic states to the list of known behaviour in metallic systems, and some of them defy the standard descriptions of 'normal' metals, known as Fermi liquid theory. Examples of these new phenomena include the fractional quantum-Hall effect, high temperature superconductivity and magnetic quantum phase transitions, which are at the focus of this dissertation. Such phase transitions occur when magnetic order is suppressed at low temperatures by means of an external control parameter, such as pressure, doping or applied field. In the vicinity of such a transition, unusual properties are expected due to strong, long range magnetic interactions, which can lead to unconventional normal states and, quite generally, to exotic forms of superconductivity. More specifically, I have studied high purity single crystals of two f-electron metals, namely CeNi₂Ge₂ and UGe₂, both close to their critical lattice densities, and examined the behaviour of their electrical resistivity as a function of temperature and pressure. CeNi₂Ge₂ at ambient pressure is naturally very close to antiferromagnetic ordering, and for the first time, CeNi₂Ge₂ is shown to be an unconventional superconductor at ambient pressure at about T_c ≃ 200mK. Furthermore, the normal state of CeNi₂Ge₂ displays an unconventional power-law of the form Δp T^1.2 over 2 decades in temperature. As pressure is applied a slow return to Fermi liquid behaviour is observed at the lowest temperatures, before a second (and as yet unidentified) ordered phase sets in at high pressures. The second system studied in this dissertation is the ferromagnet UGe₂, in which magnetism can be suppressed by pressures of about 1.4 GPa. In this material, too, superconductivity is observed at low temperatures over a narrow pressure range, but in the ferromagnetically ordered phase. I present preliminary measurements together with a phase diagram. It seems that UGe₂ is the first example of an itinerant ferromagnetic superconductor. Experimental work was carried out using a new adiabatic demagnetization cryostat, specially designed and built as an important part of the research project. The thesis describes the design of the instrument, which allows high sensitivity measurements of the resistivity over a wide range in temperature with high reliability.

APA, Harvard, Vancouver, ISO, and other styles

37

Mowll, J. L. "The responses of fungi to heavy metals." Thesis, University of Dundee, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234237.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Mansi, Sadoniben E. "Heavy metals and their ecotoxicology in estuaries." Thesis, University of Essex, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Md, Noh Mohd Fairulnizal. "Electrochemical sensors development for toxic heavy metals." Thesis, Cranfield University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422358.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Wainaina, Steven. "Effect of heavy metals on syngas fermentation." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-10203.

Full text

Abstract:

The goal of this work was to establish the suitable and limiting concentrations of Zn, Cu and Mn compounds during syngas fermentation. The results showed that cells encased in polyvinylidene difluoride (PVDF) membranes had a faster accumulation of methane in reactors containing fermentation medium dosed with 5 mg/L of each heavy metal compared to free cells. It was also revealed that total inhibition of biohydrogen production occurred in medium containing 5 mg/L Cu, 30 mg/L Zn and 140 mg/L Mn while the most suitable metal concentration level was 0.1 mg/L Cu, 0.6 mg/L and 2.8 mg/L Mn. In addition, a comparison test showed that for the most suitable metal concentration in the medium, rate of performance at pH 6 and 7 was higher than at pH 5.

APA, Harvard, Vancouver, ISO, and other styles

41

Kirk, Charles A. C. "Geochemical fractionation of heavy metals in soils." Thesis, University of Bristol, 1995. http://hdl.handle.net/1983/2153b6ab-75d5-4b4f-b648-f3ff6795b4d9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Santos, Pedro Deyrieux Centeno Ogando. "Heavy metals removal in dual media filters." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8251.

Full text

Abstract:

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente – Perfil de Engenharia Sanitária
The purpose of this study was to investigate physicochemical mechanisms for the removal of heavy metals from the effluent of Harnaschpolder’s WWTP Pilot Installation in the South of Netherlands. This effluent is partially submitted to tertiary treatment in a water reuse pilot which aims the production of water for two different end‑uses: crop irrigation in greenhouses and surface‑type water. Tertiary filters were mounted and started up at the reuse pilot and specific concentrations of heavy metals were dosed in the filters. Removal efficiencies were then calculated after the end of the experiments. As a parallel research project, the removal of HM was also carried out by inoculating selected bacteria (biosorption). Solubility curves were calculated for the dosed heavy metals (Cd, Cu, Ni, Zn) using PHREEQc programme, to predict if heavy metal precipitation occurred in the filters (using the same experimental data: temperature, pH , alkalinity, etc.). Results show that physicochemical precipitation was not the primary removal mechanism for heavy metals. The results suggest that other mechanisms such as adsorption and/or chelation may be involved in the removal of these species.

APA, Harvard, Vancouver, ISO, and other styles

43

Shi, Dalin. "Effects of trace metal pre-exposure on their bioaccumulation in marine bivalves /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202003%20SHI.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Lindström, Martin. "Predictive Modelling of Heavy Metals in Urban Lakes." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-530.

Full text

Abstract:

Heavy metals are well-known environmental pollutants. In this thesis predictive models for heavy metals in urban lakes are discussed and new models presented. The base of predictive modelling is empirical data from field investigations of many ecosystems covering a wide range of ecosystem characteristics. Predictive models focus on the variabilities among lakes and processes controlling the major metal fluxes.

Sediment and water data for this study were collected from ten small lakes in the Stockholm area, the Eastern parts of Lake Mälaren, the innermost areas of the Stockholm archipelago and from literature studies. By correlating calculated metal loads to the land use of the catchment areas (describing urban and natural land use), the influences of the local urban status on the metal load could be evaluated. Copper was most influenced by the urban status and less by the regional background. The opposite pattern was shown for cadmium, nickel and zinc (and mercury). Lead and chromium were in-between these groups.

It was shown that the metal load from the City of Stockholm is considerable. There is a 5-fold increase in sediment deposition of cadmium, copper, mercury and lead in the central areas of Stockholm compared to surrounding areas.

The results also include a model for the lake characteristic concentration of suspended particulate matter (SPM), and new methods for empirical model testing. The results indicate that the traditional distribution (or partition) coefficient K_d (L kg^-1) is unsuitable to use in modelling of the particle association of metals. Instead the particulate fraction, PF (-), defined as the ratio of the particulate associated concentration to the total concentration, is recommended. K_d is affected by spurious correlations due to the definition of K_d as a ratio including SPM and also secondary spurious correlations with many variables correlated to SPM. It was also shown that K_d has a larger inherent within-system variability than PF. This is important in modelling.

APA, Harvard, Vancouver, ISO, and other styles

45

Claus, Sonia Carmel, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "Heavy metals in biota from temperate Australian estuaries." THESIS_CSTE_SFH_Claus_S.xml, 2003. http://handle.uws.edu.au:8081/1959.7/503.

Full text

Abstract:

The detection of anthropogenic impacts in our estuaries has become a critical social, political and scientific concern in recent years. Work has focussed on the effects of these impacts on the spatial and temporal patterns of biotic assemblages and searched for bioindicators and biomarkers of pollutants that may act as early warning signs. The estuaries in temperate Southeastern Australia have a diversity of biotic assemblages living in the soft sediment. One of the most abundant macroinvertebrates is the little studies mussel, Xenostrobus securi that is found living with an assemblage of benthic biota including amphipods, crabs, isopods and tanaids, bivalves and gastropods. Two commercial fish species bream and mullet also inhabit these estuaries. Numerous stormwater drains can be found entering the estuaries through the mangrove forests lining the shores. Along with inputs of freshwater, stormwater drains are thought to be responsible for the entry of heavy metals into estuaries. These heavy metals have the potential to alter the patterns of biotic assemblages and bioaccumulate in the tissues of miacroinvertebrates, mussels and fish living within temperate estuaries. Over the time of this study the concentrations of heavy metals in the sediment tissues and shell of X.Securis varies spatially and temporally. Although this study adds substantially to current knowledge there is still more that is needed to establish X. Securis as a bioindicator. Questions remain about uptake, depuration and response to environmental gradients of heavy metals in X. Securis. Before X Securis can be used routinely in monitoring heavy metal contamination these questions need to be further investigated
Doctor of Philosophy (PhD)

APA, Harvard, Vancouver, ISO, and other styles

46

Lindström, Martin. "Predictive modelling of heavy metals in urban lakes /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2000. http://publications.uu.se/theses/91-554-4854-2/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Claus, Sonia Carmel. "Heavy metals in biota from temperate Australian estuaries /." View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20051013.092820/index.html.

Full text

Abstract:

Thesis (Ph.D.) -- University of Western Sydney, 2003.
"Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy at the University of Western Sydney Hawlesbury" Bibliography : leaves 245-278.

APA, Harvard, Vancouver, ISO, and other styles

48

Li, Litong. "Heavy metals removal from wastewater by peat absorption /." Connect to online version, 1996. http://hdl.handle.net/1989/3561.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Rose, C. J. S. "The uptake of heavy metals by three seaweeds." Thesis, Swansea University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638712.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Khastoo, D. "Uptake and toxicity of heavy metals in insects." Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637787.

Full text

Abstract:

The effects of some heavy metals at different stages of food chains are examined. The uptake of Zn or Cd by Australian white wheat, Triticum aestivum, was investigated and this wheat fed to the herbivore, Schistocerca gregaris. The organs of these insects were then examined for accumulation. Accumulation occurred in all organs examined but was higher in the epidermis and mid-gut. Nasonia vitripennis (Hymenoptera) was used as a carnivore. The effects of Zn, Cd, Cu and Hg on the longevity and survival of this insect were examined together with total accumulation at three different temperatures. Metals were more toxic at higher temperatures and the effects of different metals varied. The effects on the ultrastructure of flight muscles were examined, the main effect being a disruption of the mitochondria.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Bioaccumulation of heavy metals'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles