Thesis (Ph.D.)--York University, 2008. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 228-231). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR51671

Thesis (M.S.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: Cathy L. Cripps. Includes bibliographical references (leaves 194-212).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 189-206). Also available in electronic version.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1986. / Vita. Abstract. Includes bibliographical references (leaves 153-164). Also available via the Internet.

1) Metallothioneins (MTs) are frequently proposed as biomarkers for metal exposure and toxicity in molluscs. However, various biotic and abiotic factors influencing the rate of MT synthesis, are not well understood. The objectives of this study are to investigate the effects of biotic factors (size, sex, growth rate, nutritional state, prey type) and abiotic factors (temperature, Cd or oxidative exposure) on MT induction in Nucella lapillus and Littorina littorea, and to evaluate the usefulness of applying MT as a monitoring tool. In this study, total MTs in tissue samples were quantified using the silver saturation method. 2) Induction of MT was monitored in N. lapillus during and after exposure to Cd. N. lapillus were exposed to 500 μg Cd 1-1 (2.2% of 96h LC50) for 60 d and then placed into clean seawater for 110 d. The concentration of MT in the whole animal increased during the exposure period, peaked at Day 70, and then declined gradually. The half-life of MT was ca. 40 d. Cd concentration increased throughout the period of exposure and while in clean seawater, levelling off only after Day 120, indicating that Cd concentration could not be regulated by N. lapillus. Highest MT induction and Cd accumulation were found in the Leiblein gland of N. lapillus, suggesting that measurement of MT induction in this tissue may prove useful as a sublethal biological response to Cd contamination. 3) The combined effects of Cd and water temperature on the oxygen consumption rate (MO2) and biochemistry of fasted N. lapillus were investigated. Inhibition of MO2 by Cd increased with increasing temperature and decreasing animal size. Cd exposure caused significant reductions in glycogen concentrations in N. lapillus at both temperatures (5 & 10°C). Cd-exposed N. lapillus showed significantly higher MT concentrations in the Leiblein gland at 10°C but not at 5°C, indicating that MT synthesis is temperature dependent. Reduction in MO2 may be directly linked to Cd-induced mucus production, structural damage to gills and reduction in oxygen carrying capacity of haemocyanin. However, metabolic depression, including low MO2, glycogen stores and activity in Cd-exposed N. lapillus, may be a strategy to minimise the uptake and toxicity of Cd, and energy expenditure to spare energy reserves for detoxification and maintenance. 4) The influences of nutritional state and prey type on the survival, growth, Cd accumulation, MT induction and glycogen stores in N. lapillus were studied. Prolonged starvation and Cd exposure synergistically reduced the survivorship of N. lapillus, but feeding could help N. lapillus to combat Cd toxicity and minimise mortality. Extended fasting also caused tissue wastage, leading to higher concentrations of Cd and MT in tissues, whereas fed animals increased in weight and had lower Cd and MT concentrations because of the tissue dilution effect. Prey type significantly affected growth rate of N. lapillus and indirectly influenced Cd accumulation, MT induction and glycogen stores. Eating mussels promoted better growth and higher glycogen reserves them eating barnacles. Individual growth rate decreased with increasing Cd accumulation. Cd-exposed survivors grew faster and consumed more than control animals, implying that these survivors may have better fitness and greater tolerance to Cd toxicity. 5) Investigation of the effect of hydrogen peroxide (H2O2), and the combined effect of H2O2 and Cd on MT induction and condition index (CI) in N. lapillus was conducted. Exposure to either Cd or H2O2 alone induced synthesis of MT or MT-like proteins in N. lapillus. Exposure to high H2O2 (1000 ppm) alone or combined with Cd, and exposure to Cd (0.50 ppm) or H2O2 (2.0 ppm), resulted in significant weight loss, indicated by a reduction of CL However, CIs of N. lapillus exposed to 0.5 ppm Cd + 2.0 ppm H2O2 or 0.25 ppm Cd + 2.0 ppm H2O2, were similar to that of the control suggesting that Cd antagonistically reduces toxicity caused by H2O2 since Cd-induced MT may have a protective function against hydroxyl radicals.

Orientador: Lucia Maria Carareto Alves / Coorientador: Luciana Maria Saran / Banca: Eliana Gertrudes de Macedo Lemos / Banca: Mariana Carina Frigieri Salaro / Resumo: 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 esti... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: 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 i... (Complete abstract click electronic access below) / Mestre

Green roof technology is becoming increasingly more popular in the U.S. as it provides several economical, sociological, and ecological benefits to urban environments. One specific advantage a vegetated rooftop is known to provide is its ability to retain water and release it at reduced rates. However, with increased interest in these systems, concerns regarding their influence on water quality have been raised. Green roofs can be complex systems and the degree to which water quality might be affected may be related to green roof construction and components within. To answer questions regarding green roof influence on metal contaminants in storm water runoff, a field study and a related laboratory study were designed to investigate potential impacts these systems may have on water quality with respect to heavy metals and some micronutrients. Overall, results obtained for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn content observed in leachate collected from the constructs and media treatments from a green roof field study do not indicate that green roofs are a significant source of heavy metal and micronutrient contaminants in urban stormwater runoff and that planted Green Roof BlocksTM release less or the same metal content as planted built-in-place models. Elemental concentrations determined in effluent collected from treatments in the field study were collected for four rain events (June 28, 2007, October 18, 2007, February 4, 2008, and April 11, 2008) and compared to IEPA effluent standards to assess whether or not there were any negative impacts on water quality. Treatments for this portion of the investigation were empty built-in-place models (controls), planted and non-planted Arkalyte media at depths of 5 cm, 10 cm, 15 cm, and 20 cm in built-in place models, planted and non-planted commercial and potential green roof media in Green Roof BlocksTM. With the exception of excess Zn levels in collected effluent from the planted 10 cm treatments in October and the planted 5 cm treatments in February as well as the elevated Fe content in leachate obtained from planted glass media in October, metal concentration in effluent acquired from planted treatments were below effluent standards. Also determined to be above IEPA standards in October were Cu, Fe, and Pb measured in effluent obtained from non-planted glass media. The laboratory portion of this investigation evaluated several commercially-available substrates, bottom ash, lava rock, and composted pine bark to determine the total acid extractable and plant exchangeable content of eight elements (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn). In addition to this, effluent collected from planted and non-planted treatments using these substrates incorporated with 20% composted pine bark were examined over a course of three leaching events. While all elements examined were observed to be within levels normally found in soils, results from the total acid extractable experiments demonstrate large variation in metal concentration with each substrate and composted pine bark. With the exception of total extractable Cd, there were differences in concentrations for the remaining total acid extractable metals between the substrates and amendment tested. An artificial leaching study was conducted in the phytotron at Southern Illinois University Carbondale and consisted of eight repetitions of planted in addition to eight repetitions of non-planted pots containing known volumes of 20 % composted pine bark blended with Arkalyte, Haydite, Lassenite, Axis, bottom ash, Axis + bottom ash, and lava which were subsequently leached over three separate leaching events. Collected effluent was evaluated for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn content as well as volume of water displaced as a function of planting treatment, number of times leached, and substrate type. Metal content in the leachates were typically an order of magnitude lower than values obtained from the batch studies, and the planting, substrate, and leaching interactions varied for each metal with Pb being the most complex. The volume of water displaced upon leachate collection increased across all substrates as a function of leaching event.

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Made available in DSpace on 2014-06-11T19:30:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-15Bitstream added on 2014-06-13T19:18:45Z : No. of bitstreams: 1 chagas_gc_me_rcla.pdf: 335458 bytes, checksum: 31bbe404f398672a11d5fb2e0903d8d3 (MD5) / Universidade Estadual Paulista (UNESP) / Caranguejos de água doce Trichodactylus fluviatilis (Crustacea: Decapoda) coletados em dois sítios da Bacia do Rio Corumbataí nos períodos seco e chuvoso foram avaliados como bioindicadores para Al, Cu, Fe, Mn e Zn. Os decápodos foram necropsiados, sendo brânquias, hepatopâncreas e músculos removidos. Foram coletadas também amostras de água e sedimento nos mesmos locais de coleta dos T. fluviatilis. Os metais foram determinados por Espectrometria de Emissão Óptica com Plasma Acoplado Indutivamente e os resultados obtidos comparados através de análise de variânça (ANOVA), teste de Tukey e análises de correlação. Diferença significativa entre os sexos foi observada somente para as concentrações de Zn (macho > fêmea). Comparando as concentrações nos tecidos de T. fluviatilis, o Al foi encontrado em maiores concentrações nos hepatopâncreas em relação aos músculos. As concentrações de Cu encontradas nas brânquias foram maiores em relação aos outros tecidos. As concentrações de Fe foram menores nos músculos. As concentrações de Mn foram significativamente diferentes nos três tecidos (hepatopâncreas > brânquias > músculos) e as concentrações de Zn obedeceram a seguinte seqüência: músculo > hepatopâncreas > brânquias. O Mn e Zn foram encontrados em maiores concentrações nos caranguejos coletados no período seco. Os metais Al, Fe e Mn foram encontrados em maiores concentrações nos caranguejos coletados no sítio 2. Não foi observada diferença significativa entre as concentrações de Al, Cu, Fe, Mn e Zn determinadas nos caranguejos e o comprimento da carapaça, o que sugere um processo de acumulação dos metais pelo animal. As concentrações de Cu nos caranguejos refletiram as frações potencialmente biodisponíveis do elemento no sedimento. As concentrações de Al e Zn nos caranguejos refletiram a composição geológica... / Freshwater crabs Trichodactylus fluviatilis (Crustacea: Decapoda) collected in two sites in the Corumbataí River basin during the dry and rainy seasons were evaluated as bioindicators for Al, Cu, Fe, Mn, and Zn. Necropsies were conducted on the decapods and their gills, hepatopancreas, and muscles were removed. Water and sediment samples were also collected at the same sites as the T. fluviatilis. Metals were determined using optic emission spectrometry with inductively coupled plasma and results were compared using analysis of variance (ANOVA), Tukey test, and correlation analyses. Significant differences were observed between sexes only for concentrations of Zn (male > female). Comparing concentrations in the tissues of T. fluviatilis, Al was found in higher concentrations in the hepatopancreatic tissues than in the muscles. Concentrations of Cu in the gills were higher compared to other tissues. Concentrations of Fe were lower in the muscles. Concentrations of Mn were significantly different in the three tissues (hepatopancreatic tissue > gills > muscles) and concentrations of Zn followed the sequence: muscle > hepatopancreatic tissue > gills. Mn and Zn were found in higher concentrations in crabs collected in the dry season. Al, Fe, and Mn were found in higher concentrations in crabs collected at site 2. No significant differences in concentrations of Al, Cu, Fe, Mn, and Zn were observed in crabs of differing shell lengths, which suggests a process of metal accumulation in the animal. The concentrations of Cu in the crabs reflect the potentially bioavailable fractions of the element in the sediment. The concentrations of Al and Zn in the crabs reflected the geological composition of the region and the soluble fraction, respectively. The concentrations of Fe and Mn did not reflect the soluble and potentially bioavailable concentrations of the metals during the collection... (Complete abstract click electronic access below)

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