Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2015. / Traditional satellite systems employed for use with in-situ monitoring systems are large satellites that have a long development time, high cost and complex sub-systems. The end use of relaying data for in-situ monitoring becomes a costly application for the end user. Shifting this application to make use of nano-satellites, such as CubeSats, for data relaying will make the application more attractive to the end user when measurements are required outside existing ground based communications infrastructure. CubeSats are small, simple satellites that yield a short development time and very low cost compared to conventional satellites. Their sub-systems are generally built from off the shelf components. This keeps the designs simple, manufacture cost low with the potential for flying the latest technologies. This research set out to analyse various scenarios related to in-situ monitoring governed by parameters such as the maximum revisit time, satellite orbit altitude, quantity of sensor nodes and data quantity relayed in the system. A systems level approach is used to analyse each designed scenario using a simulation tool called Systems Tool Kit by Agilent Graphics Incorporated. The data acquired for each scenario through simulation was validated using theoretical approximation methods, which included parameters such as coverage potential, total node access time, communication link performance, power resources, memory resources, access time and number of ground stations. The focus was put on these parameters since they are the main constraints when designing a system using nano-satellites. The outcome of the research was to create an analysis reference for designing an in-situ monitoring system using nano-satellites. It outlines the methods used to calculate and simulate each of the constraints governing the system. Each designed scenario showed satisfactory performance within the defined parameters and can be practically implemented as a reference for designing similar systems. / National Research Foundation / South African National Space Agency

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2017. / Metal pollution in aquatic environments is considered a major environmental concern because of variation in several abiotic factors that impose severe restrictions on organisms living in these areas. Ceratophyllum demersum L. (family Ceratophyllaceae), a hornwort or coontail, free floating rootless macrophyte has been suggested a suitable model for investigating metal stress and was used in the current study. This study assessed the use of selected biological responses, namely antioxidant responses and changes in chlorophyll concentration in Ceratophyllum demersum L., as biomarkers of metal exposure, and also investigated the field application of these responses in the Diep River. The ultimate aim was also to determine the usefulness of C. demersum as model of metal contamination and as phytoremediator after a pollution event. An investigation of metal bioaccumulation in this macrophyte exposed to different concentrations of a combination of metals over a five-week exposure period in a greenhouse, was undertaken, as well as a field study in the Diep River, Milnerton, Cape Town and a pond (reference site) at the Cape Peninsula University of Technology, Cape Town, to validate experimental results. In the laboratory study the water was contaminated once off at the beginning of the study, to simulate a pollution event. The metal concentrations in the water and plants were measured in the four treatments and the control every week over a five-week exposure period. The samples were acid-digested and analysed with an Inductively-Coupled Plasma-Mass Spectrophotometer (ICP-MS). The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns amongst the treatment groups. This macrophyte proved highly effective in the bioaccumulation of these metals at all four exposure concentrations. The metals bioaccumulated rapidly in the plants after the water was spiked. The main focus of the study was to investigate the possible use of biochemical responses in C. demersum as possible biomarkers for metal exposure. A range of antioxidant/oxidative stress parameters were measured in the plant exposed to a combination of metals (Al, Cu, Fe, Zn) in four different treatments over the five week exposure period. Total antioxidant capacity (TAC) was measured using Total Polyphenols (TP), Ferric Reducing Antioxidant Power (FRAP) and Oxygen Radical Absorbance Capacity assay (ORAC), enzyme activity was determined using Catalase (CAT), Superoxide Dismutase (SOD), Ascorbate Acid (AsA) and Total Glutathione (GSHt) and lipid peroxidation was measured by using Thiobarbituric Acid Reactive Substances (TBARS) and Conjugated Dienes (CDs). The cocktail of the four metals induced significant changes in the antioxidant defence system of C. demersum, including the antioxidant enzyme activities. The different metal exposures disturbed the cellular redox status in the plant. The current study has demonstrated that this macrophyte shows tolerance to metal-induced oxidative stress and that it can survive under relatively high concentrations of these metals by adapting its antioxidant defence strategies. Chlorophyll was extracted in 80% chilled acetone in the dark and the absorbance values were determined using a spectrophotometer. Chlorophyll a (chl a), chlorophyll b (chl b) and total chlorophyll (chl t) contents were measured under different exposure concentrations of metals in the macrophyte. The results of this study indicated that chlorophyll contents were variable over the exposure period and no significant differences in chlorophyll concentrations were found between weeks. A field study in the Diep River and the pond located at the CPUT campus (reference site) was conducted to validate experimental results. Plants in a polluted section of the Diep River were shown to bioaccumulate metals to high concentrations. Bioaccumulation of metals in C. demersum might have induced oxidative stress, and other environmental factors such as temperature- and chemical stress might have caused chlorophyll degradation. The chlorophyll concentrations in the plants of the pond (reference site) might also have been affected by temperature and chemical stress of the water. Significantly higher AsA, CAT, ORAC, SOD and TBARS concentrations in the Diep River plants might be an indication that the plants in the river might be well adapted to the constant exposure to metals and that the plants might have developed a tolerance mechanism to cope with oxidative stress compared to those of the pond. The results show that metals are bioaccumulated quickly by C. demersum after the water is contaminated with metals, i.e. after the "pollution event". However, over time, metals are continuously exchanged between the plants and the water, accounting for the fluctuations in metal concentrations observed over time. This study has shown that C. demersum has phytoremediation potential because it was able to remove high concentrations of metals from the contaminated water. Therefore, C. demersum, can be applied as a model for metal contamination and a phytoremediator after a pollution event. The potential to antioxidant responses and chlorophyll content as biomarkers of metal exposure in C. demersum have been demonstrated.

O acesso ao recurso hÃdrico gera conflitos em todas as regiÃes do mundo. Com o aumento do consumo e da escassez da Ãgua, a tendÃncia à aumentar a inseguranÃa hÃdrica e os conflitos. Por conseguinte, à fundamental e necessÃria a geraÃÃo de ferramentas, instrumentos e metodologias de mediÃÃo que aumentem a consistÃncia dos estudos e a eficiÃncia do gerenciamento desse recurso. O desenvolvimento tecnolÃgico de um sistema de coleta automÃtica e armazenamento de dados meteorolÃgicos e hidrolÃgicos à apresentado neste trabalho. O trabalho tambÃm descreve o desenvolvimento, metodologia de calibraÃÃo, instalaÃÃo e avaliaÃÃo do funcionamento em campo experimental de sensores com caracterÃsticas especiais. O foco do desenvolvimento e avaliaÃÃo dos sensores à para atender Ãs incertezas das variaÃÃes espaÃo temporal de dados meteorolÃgicos e hidrolÃgicos do semiÃrido nordestino. Buscou-se na tecnologia de microcontroladores o desenvolvimento do sistema de aquisiÃÃo de dados, em decorrÃncia da gama de arquiteturas disponÃveis a baixo custo. Parte dos sensores desenvolvidos vem da tecnologia de transdutores industriais com base em semicondutores. A dimensÃo do valor da constante dielÃtrica da Ãgua, aliada ao modelo de funcionamento dos capacitores produziu tambÃm transdutores presentes neste trabalho. Foi possÃvel fazer a mediÃÃo e o armazenamento de dados ambientais de microbacias presentes no semiÃrido e assim apresentar a relaÃÃo entre eventos meteorolÃgicos (medidas pluviomÃtricas) e hidrolÃgicos (vazÃo de cursos de 1 ordem no (picos de descarga) semiÃrido. Umidade relativa do ar, temperatura do ar, temperatura do solo e umidade do solo tambÃm tiveram seus valores monitorados pelas sondas desenvolvidas. Testar os instrumentos à necessÃrio, pois permite aperfeiÃoar a precisÃo e a robustez do sistema. Os dados obtidos pelo sistema permitiram a construÃÃo de hidrogramas das microbacias. O canal de comunicaÃÃo dos sistema foi eficiente na coleta de dados, entretanto, faz-se necessÃrio estabelecer vias alternativas de conectividade, para obter uma melhor avaliaÃÃo e manutenÃÃo do sistema. A investigaÃÃo de desempenho do pluviÃmetro capacitivo automÃtico no laboratÃrio e em campo demonstrou a capacidade do instrumento em medir todos os parÃmetros da precipitaÃÃo pluvial. Eventos com 0,7 mm de lÃmina podem ser mensurados, inclusive a intensidade da precipitaÃÃo. / Access to water resources creates conflicts in all regions of the world. With the increase in consumption and water scarcity, the tendency is to increase water insecurity and conflict, therefore it is essential and necessary to develop tools, instruments and measurement methodologies that increase the efficiency and consistency of studies of the management of this resource. The technological development of a system for automatic collection and storage of meteorological and hydrological data is presented in this thesis. The text also describes the development, methodology, calibration, installation and evaluation of operation, in the experimental field, of sensors with special features. The focus of the development and evaluation of the sensors is to meet the uncertainties of changing space-time weather data from the semi-arid Northeast. Sought in the microcontroller technology development system of data acquisition, because its range of architectures and the low costs. Part of the sensors has developed technology on based industrial transducers and semiconductors. The range of the value of the dielectric constant of water, coupled with the operating model of the capacitors also produced transducers in this work. It was possible to make the measurement and storage of environmental data from these micro-watersheds in the semiarid and thus present the relationship between weather events (rainfall) and hydrological (flow of courses in a second order semi-arid region). Relative humidity, air temperature, soil temperature and soil moisture values were also monitored by the probes developed. Test instruments is necessary because it allows improving the accuracy and robustness of the data obtained by the system. The system has allowed to the construction of hydrographs of micro-basins. The communication channel of the system was efficient in data collection, however, it is necessary to establish alternative means of connectivity for better evaluation and system maintenance. Research on performance of capacitive automatic rain gauge in laboratory and field demonstrated the ability of the instrument to measure all parameters of rainfall. Events with in 0.7 mm range can be measured, including rainfall intensity

The biological integrity of aquatic ecosystems has become threatened by the effects of high nutrient loads, inorganic and organic chemicals. The effect of these xenobiotics needs to be investigated by the application of biotests in whole effluent toxicity testing and biomarkers in active biomonitoring. Whole effluent toxicity (WET) testing determines the toxicity/effect of whole effluent on aquatic organisms. Sub-lethal effects can be determined by analysing the levels of subcellular/physiological indicators/enzymes in aquatic organisms exposed to in situ conditions. The procedure used for in situ assessments was active biomonitoring (ABM). The aim of this study was to assess the instream health of a known contaminated system (Rietvlei Wetland System, Gauteng, South Africa) using WET and ABM methodologies. Three sites in the Rietvlei Wetland System were selected and sampling was undertaken during high flow (April 2003) and low flow (August 2003) periods. The ABM sampling protocol involved the deployment of aquatic molluscs (Melanoides tuberculata) and fish (Oreochromis mossambicus) for a period of four weeks at the sites. Following the four week exposure period the organisms were transported back to the laboratory and the following biomarkers were assessed: ethoxyresorufin o-deethylase (EROD), acetylcholine esterase (AChE) and metallothione (MT). Water samples were also collected for WET testing during the low flow period, since this was the only period where mortality was observed in the ABM organisms. Standard WET protocols were used to assess the toxicity of the water from the three sites. These protocols were: 96 h Poecilia reticulata lethality test, 48 h Daphnia pulex lethality test and 72 h Selenastrum capricorutum growth inhibition test. In addition the same biomarker analyses that were done on the ABM organisms were carried out on WET exposed D. pulex and P. reticulata. The WET testing and ABM indicated highest toxicity at Sites 1 and 3. Algal growth inhibition test showed highest stimulation of algal growth at Site 2 and inhibition at Site 3. Sites 1 and 2 showed signs of contamination by organophosphates and carbamates due to elevated AChE and reduced EROD. However there were no significant differences in AChE activity between fish tested in the 96h toxicity test and those used in ABM. Very low AChE activity was recorded in D. pulex. Snails also had lower AChE activity when compared to the exposed fish species. Metallothionein content was higher in field-exposed fish than those used in WET, however both assessment protocols indicated that Site 3 was affected the greatest by metals. Snails exhibited higher MT content than fish and D. pulex showed no MT activity. There were no significant differences in MT content between the sites. Acetylcholine esterase appears to be a relevant means of investigating biological effects of many neurotoxic contaminants on aquatic habitats and trophic levels. Metallothionein content is a good indicator of toxicity due to heavy metals for active biomonitoring as well as the WET test. Ethoxyresorufin-O-deethylase is a more difficult biomarker to work with since it shows no differences in activity between control and exposed organisms. The EROD assay does not detect very low levels of EROD induction. Acetylecholinesterase and MT are the recommended biomarker assays for the detection of sublethal responses in the WET laboratory toxicity test. The AChE activities and MT exhibit comparable results in both ABM and WET assessment protocols. In future studies WET testing needs to be complimented with a suite biomarker analyses to determine the type of pollutants in a system and sufficiently describe the pollution status of a system. / Dr. V. Wepener

M.Sc. / The Hartbeespoort Dam is located in the North-West Province, downstream of the confluence of the Crocodile River and the Magalies River. The dam was originally built for agricultural purposes and the surrounding area has many canals for irrigation. The use of pesticides for agricultural practices within the area which are transported by the canals, are of great concern. It is well known that residues of persistent pesticides (especially those of organochlorine) and insecticides are found in terrestrial and aquatic environments as well as in the organisms occupying these niches. Such xenobiotics are highly lipid soluble and lengthy exposure to them results in their high accumulation in non-target organisms, all contributing to adverse effects on the ecosystem. The upper Olifants River catchment comprises the drainage areas of the Olifants River, Klein Olifants River and Wilge River, with tributaries down to the Loskop Dam. Over the past few years, the Olifants River has been systematically impaired because of an increase in agricultural and mining activities, industrial development and urbanisation. Recent fish kills in the Loskop Dam has lead to many controversies about the water quality in the Olifants River. The aim of this study was to determine through the use of biomarker responses if it would be possible to identify whether sub-lethal pesticide exposure occurs in fish populations in the Crocodile- and Olifants River systems. Both active biomonitoring (ABM) and passive biomonitoring (PBM) were carried out at selected sites in the Crocodile River system. The ABM technique involved the transplantation of bioindicator organisms, in this case fish, and exposing them for a period of four weeks. The ABM and PBM exposures were carried out during different pesticide spraying regimes, which also coincided with high (summer) and low (winter) flow conditions. Following the exposure period, the organisms were removed and assessed for biological responses (biomarkers). General biomarker responses used in pesticide exposure i.e. acetylcholinesterase (AChE), malondialdehyde (MDA), catalase activity (CAT), protein carbonyls (PC), cellular energy allocation (CEA) and condition factor (CF) were determined. The same suite of biomarkers used in the Crocodile River system was used to determine responses in resident fish species in the Olifants River system.

This project empirically determined the controls of groundwater discharge potential and surface water chemistry in southern Taylor Slough, Everglades National Park, Florida. Potential for groundwater discharge was calculated as the difference in equivalent freshwater stage between groundwater and surface water on a daily basis for two sites (upland and coastal) along southern Taylor Slough. Upstream water stages were shown to vary most similarly to the timing of groundwater discharge potential in coastal Taylor Slough. Surface water major ion chemistry did not apparently change as a result of groundwater discharge potential. Surface water major ion chemistry at the coastal site was controlled by surface water flow direction, while at the more inland site surface water major ion chemistry was controlled by upstream water levels and evapotranspiration. Surface water phosphorus concentrations at the coastal site were controlled by groundwater discharge and flows of local surface water.

M.Sc. / Biomarkers are responses in living organisms that signify exposure to harmful substances. The use of biomarkers enables researchers to detect toxicity at suborganismal level. It can thus be used as an early warning of chronic pollution. This project employs biomarkers in preliminary field research to assess aquatic ecosystem health. The indigenous freshwater fish Oreochromis mossambicus and Labeo umbratus are used as test organisms. Mature fish are collected at polluted and unpolluted sites. Blood, brain- and liver tissue is removed and analysed. Laboratory evaluation involves the exposure of juvenile Oreochromis mossambicus to a variety of toxic chemicals in a static system to determine biomarker responses. The biomarkers investigated include acetylcholinesterase, which is inhibited by organophosphate and carbamate pesticides and pyruvate kinase, which is a ratelimiting enzyme of glycolysis. Lactate dehydrogenase is used as biomarker for muscle tissue damage and glucose-6-phosphate dehydrogenase is a key regulatory enzyme of the pentose-phosphate shunt. Osmotic anion and cation concentrations are measured to determine stress on the regulation of water- and osmotic balance. Although results from the field study is variable, some biomarkers show potential to be included in a suite of biomarkers for biomonitoring, together with other biological, physical and chemical measures. Applying techniques to assess a suite of biomarkers in key organisms, produces a more accurate reflection of ecosystem health. Exposure studies with juvenile fish produced extremely variable and unreliable results. Many repetitions of each exposure will be necessary to determine significant deviations in biomarker responses from the normal range.

Swanton Pacific Ranch is an approximately 1,300 ha working ranch and forest in northern Santa Cruz County, California, managed by California Polytechnic State University, San Luis Obispo (Cal Poly). On August 12, 2009, the Lockheed Fire burned 300 ha of forestland, 51% of the forested area on the property, with variable fire intensity and mortality. This study used existing inventory data from 47 permanent 0.08 ha (1/5 ac) plots to compare the accuracy of classifying mortality resulting from the fire using digital multispectral imagery and LiDAR. The percent mortality of trees at least 25.4 cm (10”) DBH was aggregated to three classes (0-25, 25-50, and 50-100%). Three separate Classification Analysis and Regression Tree (CART) models were created to classify plot mortality. The first used the best imagery predictor variable of those considered, the Normalized Difference Vegetation Index (NDVI) calculated from 2010 National Agricultural Imagery Program (NAIP) aerial imagery, with shadowed pixel values adjusted, and non-canopy pixels removed. The second used the same NDVI in combination with selected variables from post-fire LiDAR data collected in 2010. The third used the same NDVI in combination with selected variables from differenced LiDAR data calculated using post-fire LiDAR and pre-fire LiDAR collected in 2008. The imagery alone was 74% accurate; the imagery and post-fire LiDAR model was 85% accurate, while the imagery and differenced LiDAR model was 83% accurate. These findings indicate that remote sensing data can accurately estimate post-fire mortality, and that the addition of LiDAR data to imagery may yield only modest improvement.

Environmental samples from food processing facilities and production (farms) were taken and analyzed for the presence of indicator organisms and Salmonella spp. on food contact (FC) and nonood contact (NFC) surfaces. Salmonella was isolated from both FC and NFC surfaces of a fruit and catfish-processing plant environment, but not from a dairy processing plant or from produce packaging facility environments. Scatter plots did not show a relationship between indicator organisms and the presence of Salmonella in processing environments, regardless of the facility/environment. Salmonella ser. Gaminara and Salmonella ser. Give were prevalent in the fruit processing environment. Persistence could not be determined, as Salmonella was not detected during subsequent samplings. Two modifications of the Rappaport Vassiliadis (RV) enrichment step were evaluated and compared to the standard enrichment methods for the recovery of Salmonella. Detection rates ranged from 10.2% to 21.2% and 22.3% to 31.9% for aquaculture and sweet potato farming environments, respectively. Salmonella ser. Newport and Salmonella ser. Javiana were prevalent in the sweet potato farming environment, whereas Salmonella ser. Newport and Salmonella ser. Hartford were prevalent in the aquaculture environment. PFGE analysis revealed clusters with a high degree of genetic similarity (greater than or equal to 90%) from the fruit-processing, aquaculture, and sweet potato environments, suggesting that they represented the same strain isolated from different sampling points. Molecular characterization of isolates revealed potential contamination paths to catfish and sweet potatoes.

To simplify water quality improvement in reservoirs, it has been suggested that efforts should be focused on smaller and more manageable units such as reservoir embayment areas. Embayments are prime locations to locate marinas, parks, beaches, and residential homes. Current data and information on reservoir embayments in Tennessee was assembled into a GIS-based database. Embayments of 11 main reservoirs were mapped and digitized in ArcGIS. Initial characterization criteria include watershed size, embayment area-watershed ratio, maximum residence time, and stream influence on embayments. The characterization process was then applied to the mapped reservoir embayments in Tennessee to identify and prioritize embayments that are most likely to be affected by watershed restoration efforts. This process has potential to used by resource agencies and stakeholders to prioritize water quality improvements in reservoir embayments.