Dissertations / Theses on the topic 'Dust Environmental aspects'

La qualité de l’air des environnements intérieurs est essentielle pour la santé. Le manque de renouvellement d’air et l’humidité dans les habitats favorise la prolifération microbienne. Les effets sur la santé sont multiples et souvent associés à des maladies chroniques respiratoires, tel que l’asthme. Ces effets sont plus ou moins graves selon le niveau d’exposition et la vulnérabilité des occupants et le rôle des moisissures est pointé. Cependant, le manque d’outils valides permettant d’évaluer quantitativement l’exposition aux bactéries environnementales constitue une des principales difficultés pour mieux appréhender leur impact sur la santé humaine. Un protocole expérimental basé sur les techniques culturales a été développé et testé au laboratoire pour mesurer la survie des bactéries dans des poussières domestiques collectées au sol. L’analyse de ces poussières a permis de déterminer le temps de survie des bactéries testées. Cependant, les méthodes culturales actuelles sont limitées et n’apportent pas assez d’informations sur la composition de la flore bactérienne dans l’habitat. L’utilisation des méthodes moléculaires, tel que le séquençage haut débit, est nécessaire pour y remédier. Par ailleurs, les poussières domestiques pourraient constituer un substrat intégrateur de l’exposition chronique des occupants. Outre le développement, la standardisation, et la validation d’outils de mesure, une approche globale de sensibilisation et de prévention du risque d’exposition aux contaminants des environnements intérieurs est recommandée, en particulier chez les populations vulnérables
Indoor air quality is essential for health. Lack of ventilation and presence of humidity in habitats promotes microbial growth. The health effects are multiple and often associated with chronic respiratory diseases, such as asthma. These effects are more or less serious depending on the level of exposure and the vulnerability of occupants and the role of mold is pointed out. However, the lack of valid tools for quantitatively assessing exposure to environmental bacteria is one of the main difficulties in better understanding their impact on human health. An experimental protocol based on cultural techniques was developed and tested in the laboratory to measure the survival of bacteria in domestic dust collected on the ground. The analysis of these dusts made it possible to determine the survival time of the bacteria tested. However, current culture methods are limited and do not provide enough information on the composition of the bacterial flora in the habitat. The use of molecular methods, such as high throughput sequencing, is needed to address this. In addition, domestic dust could be an integrating substrate for chronic occupant exposure. In addition to the development, standardization, and validation of measurement tools, a comprehensive approach to raising awareness and preventing the risk of indoor exposure to contaminants is recommended, particularly for vulnerable populations

Thesis (DTech. degree: Environmental Management)--Tshwane University of Technology, 2012.
Discusses polybromobiphenyls (PBBs) and polybromodiphenyl ethers (PBDEs) are among brominated flame retardants commonly used as additive flame retardants and are now well-known pollutants. They can easily be released from household and office materials if present and tend to settle on dust. Of all the PBDEs congeners, the detection of BDE-209 is considerably more difficult than the lower congeners. Furthermore, there is no available data on the presence of PBBs and PBDEs in indoor dust in South Africa, and, therefore, it was deemed necessary to conduct the present study.

Thesis (MTech. degree in Environmental Health)--Tshwane University of Technology, 2012.
Fall out dust sampling and monitoring is becoming one of the preferred methods to determine dust pollution impact from industries/or mines on the receiving environment. Fall out dust monitoring is a useful and cost effective method of providing trend analysis of dust deposition over a period of time. It also provides an indication of the main areas of dust generation and can be conducted for both health and nuisance purposes.The aim of the study was to develop a positioning guideline for fall out dust monitoring equipment in order to optimise the existing fall out dust programme.

Thesis (MPH.) --University of Limpopo, 2006
Studies conducted on people who reside next to dust producing mines and industries show major health risks. Air pollutants from the mine and industries are inhaled by exposed miners and people who live in the vicinity (Steenland, 1995). Aim The aim of the study is to investigate non-occupational exposure to silica dust at gaMaja village in Polokwane, Limpopo Province. Methodology Study design For this study a cross sectional descriptive study design was used. Study site The study was conducted at gaMaja village near Polokwane in the Limpopo Province Sampling A total sample of 200 villagers participated in the present study. vi Data Collection Two hundred questionnaires were used to collect survey data and were coupled with four dust deposition gauges. The four gauges were mounted at four different positions in the village and were left for six hours. Data Analysis Questionnaires were analysed using SPSS computer software to determine silica-related illnesses and indicators of exposure to silicosis susceptibility. Dust samples from dust deposition gauges were analysed using a Varian 110 atomic absorption spectrometer for determination of silicon. Results The majority of both male and female participants reported that they do not wheeze (81.4%) or bring out phlegm from their chest (71.4%) as compared to those who reported episodes of cough (48%). Gauges were able to identify exposure to a particular pollutant, silica dust, and were successful.Discussion Data from questionnaires revealed that villagers do not show signs and symptoms related to silicosis, however, that does not rule out infection in a long run. The results from dust samples that were collected reveal that there are traces of silica (crystabolite) in the village of gaMaja. Dust samples were collected during normal production at the mine in the middle of summer. Conclusion Findings from this study show that people residing next to dust producing mines and industries are at high risk of health hazard. Mining companies and policy makers should take note of the findings while planning preventive strategies for reduction of air pollutants.

Indoor air quality is described as the chemical, physical and biological characteristics of air in a residential or occupational indoor environment. In residential settings, there are many contributions to indoor pollution levels namely; human activities, biological sources and outdoor air. There has been increased focus on house dust due to its potential to contain biological and chemical pollutants in indoor environments. These have the potential to cause harm to human health. The purpose of this study was to conduct toxicological analysis of house dust collected from inside selected Durban residential buildings. The objectives of this study were to isolate, identify and quantify mould occurrence in house dust samples; to measure the occurrence of heavy metals (arsenic, lead and mercury) in house dust; and to analyse the cytotoxicity of house dust on human lung bronchus carcinoma epithelial line (A549) and human lung bronchus virus transformed epithelial cell line (BBM). One hundred and five house dust samples were obtained from households that participated in the South Durban Health Study. In each home, a sample of settled dust was collected, using standardized protocols, then sieved and individually packed into polystyrene bags. The samples were taken from three surface areas namely; living room couches, bed mattresses, and carpets. Well documented methods were used for the isolation, identification and quantification of mould. The samples for heavy metals analysis were sent to Umgeni Water (chemistry laboratory, Pietermaritzburg) where standardised methods were used. Human cell lines were treated with five different dilutions of each house dust extract. Cell viability was assessed using the MTT assay. Toxic effects of house dust extract were analyzed, following house dust extract treatment and cells were stained with double dye (annexin-V- and propidium iodide) and analysed with flow cytometry, and fluorescent microscope. Cytokines were analysed by Microbionix (Neuried, German) using a Luminex®100 plate reader for multiplex human cytokines analysis. There were (n=128) mould types isolated and (n=105) were identified, of which (n=10) were predominately isolated moulds. This was further confirmed by Allerton Provincial Laboratory in Pietermaritzburg. Among the isolated genera in all three surface areas, Rhizopus spp and Penicillium spp were widely distributed throughout surface areas in greater proportion. The overall highest mean which was reported in this study and expressed in colony forming unit per gram (CFU/g) for Penicillium spp ranged (3400 - 62316 CFU/g) obtained from living room couches, followed by Rhizopus spp (5200 - 15990 CFU/g). The mould results were compared with the South African Occupational Health and Safety Act (OHSA) 85 of 1993 as amended suggested guidelines of 1,000, 000 CFU/g. The findings of this study suggest the moulds in the homes studied were below the suggested guideline. However, this does not imply that the indoor conditions are unsafe or hazardous. Instead, the findings act as an indicator of moulds presence indoors. The type of airborne mould, its concentration and extent of exposure and the health status of the occupants of a building will determine the health effects on an individual. Heavy metals were detected in the dust in the following ascending order: arsenic (As) ranged from 1.3 ug/g -18.4 ug/g (mean, 4.26 ug/g), lead (Pb) ranged from 28.0 - 872 ug/g (mean 171.66 ug/g), and mercury (Hg) ranged from 0.6 -19.0 ug/g (mean, 2.22 ug/g). The mean concentration of lead in the dust was within the range of Canadian National Classification guidelines on residential contamination (500 ug/g). There was numerous numbers of samples in this study that exceeded these guidelines. The mean concentration of arsenic was within residential soil guidelines (20 ug/g). Mercury was within limits when compared with Global Hg project guidelines of soil/residential (6.6 ug/g), thought some of samples were notably above this mean. The ability of house dust extract to lower the cell viability which was slightly above 80% (prior treatment) to less than 50% (post treatment) in both cells was observed in this study. The findings in this study showed that dust extract are toxic to human cell lines, and cells undergone a degree of apoptosis and necrosis 62% (A549) and 99% (BBM). The cytokines serve an important role in the non-specific defence external against insults. It was observed that A549 cells up-regulated the release of IL-6 and IL-8 pro-inflammatory cytokines and under-regulated the release of other cytokines analysed (IL-4, IL-13, and TNF-a). BBM cells released IL-4, IL-8 and IL-13 within limit of detection. The presence of moulds in these sampled indoor household dusts, which is comparable with findings elsewhere indoors, show that moulds act as an indicator for building conditions such as dampness, which supports mould growth. Individuals, whether they are sensitized or not, may develop allergic reactions towards spores, thus the elevated numbers of spores quantified in this study are of concern. Some of the heavy metals reported in this study were higher or marginally higher than international norms and guidelines. The findings in this study strongly suggest that house dust extract is toxic to human lung cell lines. It must be noted, however, that this study may not reflect all that happens when a human lung is exposed to house dust. The findings of this study could contribute to the development of South African indoor air guidelines. In conclusion further study needed to be undertaken with respect to air pollution disease such as allergic; the reason being this study shown the reduced expression of cytokines that are involved in allergic inflammation.
Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2009.

This thesis is an integrated study that links several disciplines-archaeology, anthropology, geography, atmospheric sciences, and microbiology. It attempts to generate an argument that central to climate change is disequilibrium in human ecologies- in my case, disease ecologies in Iceland during the 15th century. This thesis investigates the environment's effect on human adaptability. The effect of the environment on Icelanders as they moved from settlement to later periods was disquieting. The climate of the world was changing- moving from the Medieval Warm Period to the colder Little Ice Age. I analyze the disease ecology of the 15th century and also conduct an archeological and cultural analysis of the Icelandic people, to show the deficiencies in their adaptation, and submit that certain shortcomings in their physical environment, as well as the inadequate adaptive synthesis to the environment, led to a marginal adaptation. This was augmented by political unrest and problems with outside trade, which left them vulnerable and susceptible to disease pathogenesis. I discuss the climate change during the Little Ice Age, and assert that this event is the crucible that crushed Iceland after 400 years of reasonably good fortune. Hundreds of epidemics, natural disasters, and hardships befall the Icelanders. One of them is the plague, which comes twice in the 15th century. The important observation here is that the epidemiological and archeological evidence does not always match up. The principal problem is that the traditional vector for the disease cannot have survived the climate as it was in the winters during the LIA. I offer an analysis that pontificates this issue and I examine the ongoing debate concerning The Black Death in Europe. I introduce another possible explanation: the introduction of disease through environmental vectors. The creation of disease ecologies through climate change is important, in light of problems that we face today. I discuss the phenomenon of the dust storm and its connection to disease pathogenesis. By showing several key examples of dust from Africa to disease pathogenesis in the Caribbean, I make the connection a good one. In addition to this connection is the atmospheric analysis that shows incontrovertibly that the dust found in Greenland ice cores is only from Asia. Finally, there is the fact that the inveterate loci of the plague bacterium is located in the same areas that Asian Dust Events occur and travel from. I create a methodology for investigating this disease ecology and am able to show that the pathogen can be identified in situ- meaning that it can be found in geological deposits that can be properly dated. My pilot study creates a methodology for the examination of ice cores- the principal reservoir for atmospheric deposits made during the LIA. Finally, I look at the aftermath. I introduce the idea of disease ecology, as opposed to that of a healthy ecology, and suggest by the end of the thesis that within the disease ecology are created many of the platforms for emergent biological changes that translate through evolution over time. Like the bacterium in the ice core, I suggest that evidence for disease states in the history of a people can be found through laboratory techniques. The presence of the CCR5 gene mutation is indicative of such a presence. I believe that the presence of the delta 32 gene mutation found in Icelandic people is the result of being exposed to the plague in the 15th century. This thesis is a platform for future synoptic scale disease studies.
Graduation date: 2005

Bibliography: leaves 395-473. Research is directed toward demonstrating spatial variability in dust lead contamination patterns both statically and dynamically within the confines of vacant test houses, thus eliciting specific entrance pathways.

Bibliography: leaves 395-473.
xxiii, 473 leaves : ill. (chiefly col.), maps (some col.) ; 30 cm.
Research is directed toward demonstrating spatial variability in dust lead contamination patterns both statically and dynamically within the confines of vacant test houses, thus eliciting specific entrance pathways.
Thesis (Ph.D.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1999

Thesis (M. Tech. Mechanical engineering -- Vaal University of Technology
Strict emission legislation has forced industry in general to seriously consider the negative impact it has on the environment, specifically concerning emissions from burning fossil fuel into the atmosphere. In cases where emission levels exceed the allowable limit, companies are forced to operate at lower operating conditions and these load losses can result in a significant loss of revenue. This has forced companies to improve their ash filtering capabilities by optimising electrostatic precipitation systems. One of the main factors impacting on the efficiency of such a system is the distribution of the flow across the collection plates. The design of the inlet diffuser plays a major role in the ultimate distribution of the flow through the precipitator. Porous screens are positioned in the diffuser in order to distribute the flow across the total flow area with the aim to achieve a uniform distribution of the flow. CFD is widely used in industry to simulate the flow through precipitators in order to optimise the flow distribution and thus increase the efficiency of the system. It was found however that the current methods used to simulate these screens in CFD models were not well researched and employed fixed resistance values that could not reliably compensate for changes in the resistance coefficient due to a change in the angle of incidence. This study investigates advanced numerical methods for the simulation of porous screens in applications where the angle of incidence changes continuously across the face of the screen. New methods are introduced where the resistance of the screen is calculated as a function of the changing angle of incidence. The methods currently used are also investigated and compared with results from the new methods. Extensive experimental work was required to supply empirical data for the validation of the numerical methods that are proposed. For this reason, the first part of this study focused on the design construction and commissioning of a low speed wind tunnel. Results are presented and discussed for flow profiles through wide-angle diffusers at different angles and also for a number of different screens positioned in the centre of the diffuser. This study also investigates the sensitivity of a CFD simulation code to factors such as numerical discretisation schemes, turbulence models and solution relaxation specifically for wide-angle diffusers. These factors were tested for diffusers at different angles and included tests on open diffusers and also with screens positioned inside the diffuser. It was concluded that the current methods used are not adequate to capture the true flow profiles for a range of different screen geometries. Although the proposed models did improve on the limitations of the current methods, it was found that the applicability of these models is still limited and that further research would be required to develop numerical methods that are valid for a wide range of applications.
Vaal University of Technology, The National Research Foundation (NRF) and Eskom TSI

Salinisation of the shallow groundwater system has occurred coincident with the development of irrigation in the Coleambally Irrigation Area. Salinisation in irrigation areas has previously been attributed to the evaporative concentration of the water table; however, there are other sources of salt such as the accumulation of rainfall by vegetation and the dry deposition of salt-laden dusts. A significant store of crystalline gypsum, together with high concentrations of Na, Mg and Confidence limit, was found within the previously unsaturated zone of the Upper Shepparton Formation. The salt store was identified both within and outside of the groundwater mound; therefore evaporative concentration of the water table cannot be the source of salt. The transition from regional groundwater quality, as applied as irrigation to the ground surface, to shallow groundwater quality is simply explained by solubilisation of this salt store in the presence of soil CO2. Dating of basal palaeochannel sands indicates that the identified salt store, a profile of only 20 m, was accumulated during the last glacial cycle. Radiocarbon dating indicates that the peak in eluate salinity, at approximately 2 m below ground surface, is between 15,000 and 25,000 years old, coincident with the Last Glacial Maximum. The Last Glacial Maximum was a period of significantly enhanced aridity on the Australian continent. It was also found that the peak in eluate salinity coincided with a bi-modal particle size distribution. The bi-modal signature implies that these sediments were subject to the aeolian accession of dusts. It was found that the contribution of salt from dry deposition of dusts exceeded the contribution from rainfall by at least 1.9 to 11 times during the last glacial cycle. The results of this study imply that salt-laden dusts have, and continue to play an important role in the salinity and sodicity of soils in the Coleambally Irrigation Area and beyond.

Submitted in fulfillment of the requirements for the degree of Master of Health Sciences: Environmental Health, Durban University of Technology, Durban, South Africa, 2016.
The Durban University of Technology (DUT) signed the Taillores Declaration (TD) in an attempt to deal with environmental issues and subsequently waste management challenges. A few projects have been initiated within the institution to realise the TD ten point action plans. Currently there is limited data regarding the status quo at DUT. A quantitative descriptive study was conducted to analyse the situation with regards to waste management and recycling practices and to evaluate the knowledge, attitude and practices (KAP) of students towards waste management and recycling at DUT. An audit of the refuse receptacles was conducted and information obtained was plotted out on a map of two selected campuses. A questionnaire was used to collect data on the practices of waste management and recycling from nine departments. A total of 403 students from the Indumiso and Riverside campuses of DUT were recruited for the KAP study. The findings revealed that refuse receptacles are provided inconsistently and that there is a lack of planning around the provision of these receptacles. Departmental practices regarding waste management and recycling were found to vary from one department to the next. The KAP study results indicated that the students’ knowledge regarding waste management and recycling is poor and their attitudes and practices towards waste management and recycling may be improved by education and enforcement of policy. It is essential to develop a policy regarding waste management and recycling for DUT. In addition, a learning programme should be implemented for all new students entering DUT and during orientation.
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