Made available in DSpace on 2014-06-11T19:28:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-11Bitstream added on 2014-06-13T18:57:59Z : No. of bitstreams: 1 silva_ceo_me_botfca.pdf: 992973 bytes, checksum: 0d39fa727acc22130c9ec40047fd3911 (MD5) / A concentração de CO2 na atmosfera vem aumentando significativamente desde a Revolução Industrial. Devido aos potenciais impactos da elevação do CO2 do ar sobre os diversos patossistemas, foram realizados ensaios em ambiente controlado para verificar os efeitos da elevação da concentração de CO2 do ar sobre Cylindrocladium candelabrum em folhas destacadas e mudas de Eucalyptus urophylla. Em três ensaios, folhas destacadas foram acondicionadas em bandejas plásticas com espuma umedecida, com concentração de 607 ± 86, 705 ± 105, 855 ± 152 e 1101 ± 305 μmol mol-1 de CO2 do ar, pulverizadas com conídios do patógeno (2 × 105 conídios mL-1) e mantidas a 28 ± 1,7 oC e fotoperíodo de 12 h por 21 dias. Foram avaliadas a severidade da mancha foliar e a esporulação do patógeno. Em dois ensaios com mudas de eucalipto, as mudas foram cultivadas em tubetes, mantidas em caixas plásticas contendo vermiculita no fundo e mantidas nas concentrações de 451 ± 35 (controle), 645 ± 118, 904 ± 116, 1147 ± 216 μmol mol-1 de CO2 por 30 dias para aclimatação. Após este período, as mudas foram pulverizadas com conídios do patógeno e mantidas sob as mesmas condições anteriores por seis dias. Foram avaliadas a incidência de folhas lesionadas, a severidade da mancha foliar e o número de folhas contendo esporos do patógeno. A altura das mudas, o diâmetro do caule e o peso da matéria seca da parte aérea e da raiz também foram avaliados. Nos ensaios com folhas destacadas, o aumento da concentração de CO2 do ar não teve efeito sobre a severidade da mancha foliar e esporulação do patógeno. Nas mudas, a elevação da concentração de CO2 do ar diminuiu a incidência de folhas lesionadas, a severidade da doença e o número de folhas contendo 2 esporos do patógeno quando comparados ao controle. Nas variáveis de... / The concentration of CO2 in the atmosphere has been increasing significantly since the Industrial Revolution. Because of the potential impacts of the increase in CO2 from the air on the various pathosystems, assays were carried out in a controlled environment to check the effects of elevation of the concentration of CO2 from the air on Cylindrocladium candelabrum in detached leaves and seedlings of Eucalyptus urophylla. In three trials, detached leaves were wrapped in plastic trays with foam moistened with concentration of 607 ± 86, 705 ± 105, 855 ± 152 and 1101 ± 305 μmol mol-1 CO2 from the air, sprayed with conidia of the pathogen (2 × 105 conidia ml-1) and maintained at 28 ± 1.7 oC and photoperiod of 12 h for 21 days. It was evaluated the severity of leaf spot and the sporulation of the pathogen. In both experiments with seedlings of eucalyptus, the seedlings were grown in plastic tubes, kept in plastic boxes containing vermiculite at the bottom and kept in concentrations of 451 ± 35 (control), 645 ± 118, 904 ± 116, 1147 ± 216μmol mol-1 CO2 per 30 days for acclimatization. After this period, the seedlings were sprayed with conidia of the pathogen and kept on the same conditions for six days. It was evaluated the incidence of lesioned leaves, leaf spot severity and the number of leaves containing spores of the pathogen. The height of the seedlings, the diameter of the stem and the weight of the dry matter of the aerial part and root were also evaluated. In the tests with detached leaves, the increase of CO2 concentration had no effect on the severity of leaf spot and sporulation of the pathogen. In seedlings, the elevation of CO2 concentration decreased the incidence of leaves lesioned, the severity of the disease and the number of leaves containing spores of the pathogen when compared to the control. In the... (Complete abstract click electronic access below)

Orientador: Raquel Ghini / Banca: Magali Ribeiro da Silva / Banca: Celso Garcia Auer / Resumo: A concentração de CO2 na atmosfera vem aumentando significativamente desde a Revolução Industrial. Devido aos potenciais impactos da elevação do CO2 do ar sobre os diversos patossistemas, foram realizados ensaios em ambiente controlado para verificar os efeitos da elevação da concentração de CO2 do ar sobre Cylindrocladium candelabrum em folhas destacadas e mudas de Eucalyptus urophylla. Em três ensaios, folhas destacadas foram acondicionadas em bandejas plásticas com espuma umedecida, com concentração de 607 ± 86, 705 ± 105, 855 ± 152 e 1101 ± 305 μmol mol-1 de CO2 do ar, pulverizadas com conídios do patógeno (2 × 105 conídios mL-1) e mantidas a 28 ± 1,7 oC e fotoperíodo de 12 h por 21 dias. Foram avaliadas a severidade da mancha foliar e a esporulação do patógeno. Em dois ensaios com mudas de eucalipto, as mudas foram cultivadas em tubetes, mantidas em caixas plásticas contendo vermiculita no fundo e mantidas nas concentrações de 451 ± 35 (controle), 645 ± 118, 904 ± 116, 1147 ± 216 μmol mol-1 de CO2 por 30 dias para aclimatação. Após este período, as mudas foram pulverizadas com conídios do patógeno e mantidas sob as mesmas condições anteriores por seis dias. Foram avaliadas a incidência de folhas lesionadas, a severidade da mancha foliar e o número de folhas contendo esporos do patógeno. A altura das mudas, o diâmetro do caule e o peso da matéria seca da parte aérea e da raiz também foram avaliados. Nos ensaios com folhas destacadas, o aumento da concentração de CO2 do ar não teve efeito sobre a severidade da mancha foliar e esporulação do patógeno. Nas mudas, a elevação da concentração de CO2 do ar diminuiu a incidência de folhas lesionadas, a severidade da doença e o número de folhas contendo 2 esporos do patógeno quando comparados ao controle. Nas variáveis de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The concentration of CO2 in the atmosphere has been increasing significantly since the Industrial Revolution. Because of the potential impacts of the increase in CO2 from the air on the various pathosystems, assays were carried out in a controlled environment to check the effects of elevation of the concentration of CO2 from the air on Cylindrocladium candelabrum in detached leaves and seedlings of Eucalyptus urophylla. In three trials, detached leaves were wrapped in plastic trays with foam moistened with concentration of 607 ± 86, 705 ± 105, 855 ± 152 and 1101 ± 305 μmol mol-1 CO2 from the air, sprayed with conidia of the pathogen (2 × 105 conidia ml-1) and maintained at 28 ± 1.7 oC and photoperiod of 12 h for 21 days. It was evaluated the severity of leaf spot and the sporulation of the pathogen. In both experiments with seedlings of eucalyptus, the seedlings were grown in plastic tubes, kept in plastic boxes containing vermiculite at the bottom and kept in concentrations of 451 ± 35 (control), 645 ± 118, 904 ± 116, 1147 ± 216μmol mol-1 CO2 per 30 days for acclimatization. After this period, the seedlings were sprayed with conidia of the pathogen and kept on the same conditions for six days. It was evaluated the incidence of lesioned leaves, leaf spot severity and the number of leaves containing spores of the pathogen. The height of the seedlings, the diameter of the stem and the weight of the dry matter of the aerial part and root were also evaluated. In the tests with detached leaves, the increase of CO2 concentration had no effect on the severity of leaf spot and sporulation of the pathogen. In seedlings, the elevation of CO2 concentration decreased the incidence of leaves lesioned, the severity of the disease and the number of leaves containing spores of the pathogen when compared to the control. In the... (Complete abstract click electronic access below) / Mestre

The X-band EPR spectrometry system was modified to allow for the in situ monitoring of free radical changes in attached, intact plant leaves, which were caused by stress factors such as exposure to excessive photon flux density, ozone or sulphur dioxide. This was done through use of the dewar insert of the variable temperature accessory as a guide, the construction of 'T' shaped cellulose acetate holders to which leaves could be attached with adhesive tape, and modification of the gas flow system used for controlled temperature studies. Kinetic studies of free radical formation were possible with leaves which had minimal underlying Fe⁺⁺ and Mn⁺⁺ signals. In leaves with large underlying signals a Varian software program was used to subtract overlapping signals from each other, thereby revealing the free-radical signal changes which occurred under different light regimes and stress conditions. Preliminary investigation disclosed the formation of a new signal upon prolonged exposure to far-red light and the effect of oxygen depletion upon photosynthetic Signals I and II. Leaves subject to high photon flux density reveal an unreported free-radical signal, which decays upon exposure to microwave radiation; and concomitant damage to Photosystems I and II. Upon elimination of this signal leaves return to the undamaged state or reveal permanent damage to either photo-system, depending upon the degree of damage. Kentucky bluegrass and perennial ryegrass leaves subject to low levels of ozone (up to 80ppb) for periods of 8 hours show no changes in free-radical signal formation. At intermediate levels of ozone (80-250ppb) a new free-radical signal was formed within 3 hours of fumigation, Signal II was decreased and Signal I decayed. These changes were reversible if fumigation was terminated. At fumigation levels exceeding 250ppb a different new irreversible free-radical signal was formed in darkness within 1.5 hours of fumigation. Radish, Kentucky bluegrass and perennial ryegrass leaves subject to high levels of sulphur dioxide (10-500ppm) reveal the formation of Signal I upon irradiation with broad-band white or 650nm light, thereby indicating an interruption of normal electron flow from PSII to PSI. Damage to the oxygen-evolving complex and reaction centre of PSII is also revealed through changes in Signal II and the Mn⁺⁺ signal. These changes in the normal EPR signals are dose-dependent. Leaves subject to low levels of sulphur dioxide (600-2000ppb) reveal the disappearance of Signal I after 3 hours of fumigation and the formation of a new free-radical signal with parameters similar to the sulphur trioxide free-radical signal. These latter changes are partially reversible upon termination of fumigation. After prolonged exposure to either ozone or sulphur dioxid a free-radical signal with parameters similar to the superoxid anion free-radical signal is formed in plant leaves. / Land and Food Systems, Faculty of / Graduate

Fertile White Leghorn (Gallus gallus) and Bobwhite Quail (Colinus virginianus) were subjected to 15 min exposures produced by burning solid rocket motor (SRM) fuel. Comparative mortality data were collected. Chicken eggs were further used to study the effects of exposure on water relations and blood gas parameters. Chicken embryos exposed once on day 19 or incubation demonstrated and LD50 of 204 ppm; the LD50 for quail embryos was 175 ppm. When mortality was regressed on the final exposure concentration, chicken and quail embryos exposed on days 12 and 19 showed LD50's of 127 and 86 ppm respectively, and embryos exposed on days 4, 12, and 19 had LD50's of 75 and 56 ppm. Quail embryos appeared to be more sensitive to SRM exhausts than chicken embryos, probably owing to the larger surface area to volume ration of the egg. Embryos exposed to a small daily concentration had an MLC of 117 ppm and an LD50 of approximately 200 ppm for cumulative exposure concentrations. This suggested that individual exposures were additive in effect. Eggs exposed at temperatures less than 37.5 C showed reduced lethality, while exposures at greater temperatures increased lethality. The rate of water loss from chicken eggs measured over an eight hour period increased 5 times because of a 15 min exposure. Since the increased rate of dehydration occurred during the exposure, the hydroscopic effects of exposure were extreme. When eggs lose the 18% of the initial weight normally lost from evaporation during incubation due to exposure, no more water loss was seen to occur. Blood gas analyses on 12 day embryos showed decreased pH at cumulative exposure concentrations greater than 200 ppm. Carbon monoxide in the exhausts probably increased carboxyhemoglobin, reducing buffering capacity. The acidosis was partially compensated by increased HCO3-, Exogenously derived C1-, plus increased HCO3- may shift intracellular K+, making the serum hyperkatremic. Dehydration effects further increased serum hypertonicity.

Grafts were made using 2-0 rootstock and scion from 12 ortets of eastern white pine (Pinus strobus L.) growing at the Radford Army Ammunition Plant (RAAP). The 12 ortets represented 4 symptom severity classes (3 ortets/class) ranging from trees with > 25% of their crowns exhibiting necrotic tipburn (Class I) to those with healthy crowns (Class IV). Grafts were made in spring 1976 and ramets were grown in a greenhouse drawing charcoal filtered air. Each treatment was performed twice, on separate days for a total of 10 ramets/clone/ treatment. Five ramets/clone were used in each 6 hour treatment. The current years growth was 7-10 weeks old when treated. The treatments were as follows: 1) 0₃-10 pphm, 2) 0₃-30 pphm, 3) NO₂-10 pphm, 4) NO₂-30 pphm, 5) 0₃-10+NO₂ -10 pphm, 6) 0₃-10+NO₂ -30 pphm, 7) no pollutant. The fumigation chamber was a modified open-top field chamber located indoors. Environmental conditions during the 14 treatments averaged: 26 C, 64% RH, and 16 Klux. The ramets were evaluated prior to fumigation and then 2, 7, and 14 days thereafter for visible symptoms. The overall injury was generally light with only 11% of the clone treatment combinations exhibiting injury on > 25% of the needle fascicles. Clones I-1 and I-2 were the most sensitive clones while clones III-1, IV-2 and to a lesser degree clones III-3 and IV-1 were tolerant. These results agree with field ratings of eastern white pine sensitivity at the RAAP and provide the first step in the development of an air pollution bioindicator system at the installation. / Master of Science

Most existing environmental chambers cannot simulate dynamically changing environmental conditions. Hence there is a need for a dynamically controlled artificial environment for plant studies. This project demonstrates the control of temperature, humidity and SO₂ concentration in a Continuous Stirred Tank Reactor (CSTR) system using feedback control through a computer. An IBM-PC was connected to the measuring instrumentation and control equipment through a data acquisition and control system. Temperature and humidity were controlled by an ON-OFF control scheme. Sulfur dioxide concentration was controlled by means of a modified proportional derivative control algorithm. The system is capable of achieving a wide range of temperatures (7°C to 40°C), humidities (30% to 97%), and SO₂ concentrations. Temperature is maintained within ±0.5°C of the desired value and humidity is controlled within ±4% of the desired value. Sulfur dioxide concentration is kept within ±10% of the desired concentration. It was found that as humidity increases, the supply rate of SO₂ must be increased to maintain a given concentration. Software response time is slow. This causes time lags in the modification of the controlled parameters to achieve desired values. The heating and cooling characteristics of the system can be improved by better insulation of the chamber walls. The system demonstrates that computerized feedback control is practical for application to controlling environmental parameters in a fumigation chamber. / Master of Science

Yellow poplar (Liriodendron tulipifera L.) and loblolly pine (Pinus taeda L.), families 2-8 and 540, seedlings were fumigated with 0.07 ppm ozone, 0.06 ppm sulfur dioxide 0.07 ppm ozone + 0.06 ppm sulfur dioxide, 0.06 ppm sulfur dioxide + 0.10 ppm nitrogen dioxide and 0.07 ppm ozone + 0.06 ppm sulfur dioxide + 0.10 ppm nitrogen dioxide for 35 consecutive days, 6 hr/day. Control seedlings received charcoal-filtered air. Ozone or sulfur dioxide did not significantly affect height growth or dry weight of yellow poplar seedlings. All other treatments significantly reduced height growth and dry weight after 2 weeks of fumigation. Height growth effects of loblolly pine families were not repeatable from one year to the next in replicate experiments and weekly growth trends in the two experiments were reversed. Environmental factors related to time of year were thought to be involved with this growth trend reversal. Root dry weight was found to be a more sensitive indicator of air pollution stress than either shoot dry weight, height growth or visible symptoms. Loblolly families 2-8 and 540 were not found to be differentially sensitive to pollutant treatments. Loblolly pine seedlings, nonmycorrhizal and mycorrhizal with Pisolithus tinctorius, were fumigated with 0.07 ppm ozone and 0.06 ppm sulfur dioxide singly and in combination, 6 hr/day, for 35 consecutive days. Height growth of mycorrhizal and nonmycorrhizal seedlings was not affected by fumigation. Root dry weight of nonmycorrhizal seedlings was significantly reduced by all pollutant treatments in two replicate experiments. A similar reduction in root dry weight of mycorrhizal seedlings did not occur. Shoot dry weight of nonmycorrhizal seedlings was reduced in four of six pollutant treatments, and in one of six treatments of mycorrhizal seedlings. Mycorrhizal formation was extensive regardless of treatment. Apparent photosynthesis, measured every 4 days, was variable and significant differences among treatments did not occur. Total reducing sugar concentrations of roots were an inconclusive indicator of air pollutant stress. / Ph. D.

Lichens are an important part of the biota in western Oregon forests, where they perform valuable ecological roles and contribute significantly to biodiversity. Lichens in western Oregon are threatened by a number of factors including air pollution and land use practices. If we wish to maintain the persistence of lichens in future landscapes it is critical that we understand the responses of lichen communities and individual lichen species to the environment and forest structure. This dissertation explores factors that are related to differences in lichen community composition and the distributions of individual lichen species in the western Cascades of Oregon, using a large landscape scale data set. I sought to relate major gradients in lichen community composition to environmental factors, and describe differences in lichen communities with respect to forest age (Chapter 2). I found three major gradients in lichen communities at a landscape scale in the western Oregon Cascades. These gradients were related to climate as expressed by elevation and annual temperature, air quality, north-south position, the richness of epiphytic macrolichens, and forest age. I developed a rarity score, which can be used to identify hotspots of rare species diversity at a landscape scale (Chapter 3). I then built descriptive models of this rarity score to identify abiotic and biotic factors associated with the occurrence of rarity hotspots. I found that models of rarity score that used explanatory variables based on lichen community composition performed better than models that used explanatory variables based solely on environmental factors. I narrowed my focus to the level of individual species responses to the environment and forest structure by developing habitat models for 11 lichen species in the western Cascades (Chapter 4). We selected these species because they performed important ecological roles, were rare across the landscape and associated with old growth forests, or because their distributions were poorly understood. These models can be used to increase the efficiency of landscape level surveys for rare species, predict the response of these species to forest management practices, and understand factors associated with the distributions of these lichens. / Graduation date: 2006

Thesis submitted in partial fulfilment of the requirements for the degree Master of Technology: Chemical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2013 / In South Africa, the Department of Environmental Affairs (DEA) under the National Environmental Management Act, 1998 (Act 107 of 1998) (“NEMA”) sets out a series of environmental management principles that apply to the interpretation and application of all legislation that may affect the environment. Since 1998, various specific environmental statutes that fall under the NEMA framework have been promulgated, including the National Environmental Management: Air Quality Act, Act 39 of 2004 (NEM: AQA).NEM:AQA provides norms and standards for all technical aspects of air quality management. The National Framework (Sections 7 and 8 of NEM:AQA) must provide mechanisms, systems and procedures to promote holistic and integrated air quality management through pollution prevention and minimisation at source, and through impact management with respect to the receiving environment, from local scale to international issues. Among other measures, the NEM:AQA (Section 9) requires the establishment of Ambient Air Quality Standards and Emission Standards. These standards were promulgated in December 2009 and March 2010 respectively. Air quality monitoring stations, which sample and analyse pollutant concentrations continuously, are a common method of assessing air quality in a region. But a few continuous monitors located in source given region or airshed are inadequate for assessing compliance with ambient air quality standards – they are only able to monitor concentrations at a fixed site, not through the entire region of impact. In contrast, the ambient air quality standards are applicable everywhere. Air quality models estimate ground level ambient concentrations throughout the modelling domain, and in principle (subject to proper validation) provide better estimates of area-wide concentrations and hence the basis for assessing compliance with air quality standards. The United States Environmental Protection Agency (US EPA) approved atmospheric air dispersion models AERMOD and CALPUFF were used in this thesis to predict the ground level concentrations of SO2 emitted from Chevron Refinery (Cape Town), for the year 2010. The modelling is validated by comparing measured ambient concentrations with modelled concentrations. The results showed AERMOD-modelled annual average values for 2010, based on refinery emissions only, are in good agreement with monitored values at the Table View and Bothasig sites, predicting the monitored values by -11% and +17% respectively. The 24-hr average values similarly are in good agreement with monitored values, on average over-predicting by 9% at Table View, although the fit of the day-to-day modelled vs monitored values is comparatively poor (R2=0.32); at the Bothasig site the corresponding values are - 36% and R2= 0.089. The AERMOD-modelled isopleths imply that the 2010 annual average concentrations exceeded the South African Standard of 50 μg/m3 in a small area in the immediate vicinity of the refinery. The hourly and 24-hourly average standard concentrations of 350μg/m3 and 125μg/m3 respectively are exceeded in significantly larger areas. The allowable exceedences for hourly and 24-hourly averages are also exceeded, implying that the hourly and 24-hourly standards were exceeded. CALPUFF-modelled average values for 2010, based on refinery emissions only, are in comparatively poor agreement with monitored values at the Table View and Bothasig sites, under-predicting the monitored values by -20% and -61% respectively. Since the AERMOD-modelled concentrations are in far better agreement with monitored concentrations, only AERMOD was used for further analysis. The Emission Standards promulgated in March 2010 included emission limit values for sulphur dioxide emitted from oil refineries. If the actual 2010 emission rates were adjusted downwards to match the emission standards (to be complied with from 1 April 2015), AERMOD modelling indicates that the annual, 24-hourly and hourly Ambient Air Quality Standards would not be exceeded. Based on this case study, the current Emission Standard for SO2 emissions from existing crude oil refineries is therefore coherent with the Ambient Air Quality Standards. Regulatory air dispersion modelling practices in South Africa are being standardised for model applications regulatory purposes and to ensure that dispersion modelling practices are undertaken in a compatible form to ensure that results from one dispersion model study can be compared directly to those from another. In this study both AERMOD and CALPUFF modelling complied with the draft South African guidelines for Air Quality Modelling, yet the CALPUFF- modelled outputs differed significantly from the monitored values. This emphasizes the importance of the inclusion of modelling validation in guidelines for modelling for regulatory purposes. The 2012 draft regulation should be amended to make validation of regulatory dispersion modelling compulsory rather than optional as per the draft.