published_or_final_version / abstract / China Development Studies / Master / Master of Arts

It is common knowledge that water is one of the basic needs for human beings. However, the consumption of contaminated water can lead to waterborne diseases and fatalities. It is, therefore imperative to constantly monitor the quality of potable water. There are numerous technologies used for water quality monitoring. These technologies are relatively effective however these tests are expensive and complex to use, which then require experienced technicians to operate them. Other tests are not rapid, making consumers of water susceptible to waterborne diseases. In this study, dye-doped, surface functionalized silica nanoparticles (SiNPs) and surface-functionalized magnetic nanocomposites (MNCs) were proposed as materials that can be applied in order to reduce the time taken to get results as well as to make the processes less complex and portable. The aim of this study was to synthesize and characterize surface functionalized dye-doped SiNPs and surface functionalized MNCs for detection and preconcentration of in water. Additionally, proof of concept had to be shown using the synthesized materials. SiNPs were the materials of choice due to their easily functionalized surfaces and their strong optical properties. SiNPs are photostable and they do not leach in solution due to the inert nature of the silica matrix in aqueous media. MNCs were chosen as materials of choice for preconcentration of E. coli in water because they are easy to synthesize and they can be applied in various biological applications due to their functional groups. SiNPs were synthesized using the water-in-oil microemulsion. The SiNPs were further functionalized with amine and carboxyl groups and avidin. Thereafter, they were bioconjugated with biotinylated anti-E. coli antibodies. The pure and surface functionalized SiNPs were characterized using ATR-FTIR spectroscopy, FE-SEM, HR-TEM, Zeta Sizer, UV-vis spectroscopy and spectrofluorometry. The application of the dye—doped surface functionalized SiNPs in E. coli detection was characterized using the fluorescence plate reader. The SiNPs were spherical and uniform in size. They increased in size as they were being functionalized, ranging from 21.20 nm to 75.06 nm. The SiNPs were successfully functionalized with amine and carboxyl groups as well as with avidin and antibodies. Two methods were investigated for carboxyl group attachment (direct and indirect attachment) and the direct attachment method yielded the best results with a surface charge of -31.9 mV compared to -23.3 mV of the indirect method. The dye loading was found to be 1% after particle synthesis. The optical properties of the Ru(Bpy) dye were enhanced 3 fold when they were encapsulated in the Si matrix. The SiNPs were binding to the E. coli cells and enabled detection. MNCs were synthesized through in-situ polymerization. The MNCs were characterized using ATR-FTIR spectroscopy, SEM, TEM and XRD. The MNCs were successfully functionalized with carboxyl groups. The increase in size of the nanocomposites as seen in SEM images proved that the Fe3O4 was successfully encapsulated in the polymer matrix. The MNCs were proven to be magnetic by a simple magnetism test whereby they were separated in an aqueous solution using an external magnetic field. The antibody-labelled MNCs were binding to the E. coli cells as shown in TEM images. E. coli cells were removed from water at varying concentrations of 1x106 CFU/mL to 1x109 CFU/mL at 10 mL volumes. This study has demonstrated that dye-doped SiNPs amplify the signal of E. coli cells using fluorescence. The study has also demonstrated that the MNCs can be applied in sample preconcentration and enrichment for E. coli detection. However, further studies should investigate and optimize the combination of the two techniques in a point of use device for water quality testing of 100 mL-samples as per the requirement of the SANS 241 standard. / Civil and Chemical Engineering / M. Tech. (Chemical Engineering)

<p>The Eerste River is a river system which has, over the years, been subjected to human interference. The purpose of this study was to investigatge temporal and spatial trends in the water quality of the Eerste River between 1990 and 2005. The study results revealed that the major trends in the water quality of the Eerste River are more spatial than temporal.</p>

D.Ing. / Measuring the efficiency of water utilities has been a constant challenge to various stakeholders in the water sector. There are several factors that influence the efficiency of utilities. The following study examines the different factors and establishes a model to quantify the efficiency of water utilities using limited number of variables. It utilises Fuzzy Logic to develop the measurement model. The developed method can also be used to configure a new water utility for efficiency. In addition, the research highlights some possible imperfections in the water policies that can result in an inherent inefficiency of a water utility. The developed model can assist in setting ceiling levels for utility's water assets and labour, to ensure efficiency. The model is generic and can be applied to any country or community, and can be used to configure water utilities for the poor. The Model utilised "Matlab Fuzzy Tool Box student version 2009a" software as a tool to develop the Fuzzy Inference Engine for Utility Efficiency. The study is a contribution to the domain of knowledge of water engineering science.

The worldwide natural occurrence of high levels of arsenic (As) in groundwater and its deleterious effects on human health have inspired a great amount of related research in public health and geosciences internationally. With >100 million people in South and Southeast Asia exposed to >10 µg/L As in shallow groundwater that they use for drinking, the installation of deeper, low-As wells has emerged as a major strategy for lowering the exposure. As the magnitude of deep pumping continues to increase, this work focuses on the geochemical and hydrologic questions surrounding the vulnerability and sustainability of low-As aquifers in Bangladesh, the country most affected by As crisis. In an effort to better understand the residence time of groundwater in low-As aquifers at depth, radiocarbon (14C) and 13C in dissolved inorganic carbon, tritium (3H), stable isotopes of hydrogen (2H) and oxygen (18O), and noble gas concentrations were measured across a ~25 km2 area of Araihazar, ~30 km east of Dhaka. Groundwater from >120 m depth is shown to be ~10,000 years old and its isotopic signatures indicate that recharge occurred at the time of changing climate from the late Pleistocene to early Holocene, with little recharge occurring since. In contrast, the intermediate depth low-As aquifers (<120 m) have a heterogeneous distribution of groundwater chemistry and ages, and contain groundwater recharged <60 years ago in certain locations. In one such area surrounding a small village, the effects that subsurface clay layer distribution has on recharge patterns and redox status of the intermediate aquifer was investigated. The relevant hydrogeologic and geochemical processes that led to documented failures of a community well at the site were assessed using a combination of solid and water phase geochemistry with tritium-helium (3H/3He) dating, hydraulic head monitoring, and pumping tests. Organic matter seeping from a compressible clay layer, which is subject to a pumping-induced, downward hydraulic gradient, reduces iron oxides and helps release As in the grey, upper part of the intermediate aquifer. No recent recharge was detected by 3H measurements in the upper, grey sand layer, however a layer of orange sand beneath it contains groundwater that was recharged 10-60 years ago. This groundwater laterally bypasses the confining clay layer to recharge the middle of the aquifer and contains dissolved As levels of <10 µg/L. In this particular case, the pore water that leaches from clay layers contributes to As contamination, whereas the lateral recharge with shallow groundwater coincides with the low-As depth. Thus, clay layers may not always protect the low-As aquifers from As contamination, even if they can block direct vertical recharge with shallow groundwater enriched in As and organics. Finally, the adsorption of As to aquifer sediments, as a natural mechanism of the low-As aquifer defense against contamination, was assessed in the field via a column study. The column experiments were conducted by pumping shallow, high-As groundwater through freshly collected sediment cores to quantify the retardation of As transport through the aquifer. This study demonstrated an elegant method of assessing contaminant transport under nearly in situ conditions that resulted in sorption estimates similar to those made by field studies using more challenging methods or located at hard-to-find sites with convenient flow patterns. My work, therefore, contributed to a better understanding of low-As aquifers in Bangladesh from the perspectives of both the groundwater flow and water-sediment interactions on various scales, and it integrated methods that can be employed elsewhere to characterize aquifers and study contaminant transport.

Waterborne disease is a significant contributor to the global burden of disease, in particular among high-risk populations in developing nations. State-of-the-art methods for the enumeration of microbial pathogens in drinking water sources have important limitations, including high initial cost, 24-48 hour delays in results, high staffing and facility requirements, and training requirements which all become especially problematic in the developing nation context. A number of alternative approaches to microbial water quality testing have been proposed, with the goal of decreasing the required testing time, decreasing overall costs, leveraging appropriate technology approaches, or improving sensitivity or specificity of the water quality testing method. One approach that may offer solutions to some of these limitations involves the deployment of sensor networks using fluorescent spectroscopy to detect intrinsic protein fluorescence in water samples as a proxy for microbial activity. In recent years, a number of researchers have found significant and meaningful correlations between indicator bacteria species and the protein fluorescence of drinking water samples. Additionally, advances in the semiconductor industry could be used to drive down the cost of such sensors. This technology may also be extensible to other water quality parameters, including dissolved organic matter or the presence of fluorescent pollutants. In this thesis, a literature review describes the fundamentals of fluorescence spectroscopy, historical and recent work regarding the fluorescence of the amino acid tryptophan and associated bacterial fluorescence, possible mechanisms for this association, and potential applications of this technology for drinking water quality monitoring and waste water process control. Extensibility of the technology is also discussed. Next, experimental methodology in reproduction of similar results is described. Samples were taken from seven (7) surface water sources and tested using membrane filtration and an off-the-shelf fluorescence spectrometer to help examine the association between the presence of indicator bacteria and the tryptophan fluorescence of the water sample. The results, showing an association of R2 = 0.560, are compared to the results of recent similar experiments. Finally, two prototypes are described, including their design requirements and data from prototype testing. The results of the testing are briefly discussed, and next steps are outlined with the goal of developing a low-cost, in-situ microbial water quality sensor using fluorescence spectroscopy principles.

It is the responsibility of humans, as environmental stewards, to monitor our impact on the environment so that efforts can be made to remediate the effects of our actions and change behaviors. To better understand our environmental footprint, sensitive and simple analytical methods are needed to quantify the contaminants that we discharge into our natural surroundings. Emerging environmental contaminants are of particular concern because there is limited or no information available on their occurrence, fate, and toxicity. As a result, the implications of using these chemicals are not well understood. Therefore, accurate environmental data are needed to help scientists and government policy-makers make informed decisions on research directions and chemical regulation. However, challenges exist for the analysis of emerging contaminants, including a lack of suitable analytical standards and internal standards, their broad range of chemical properties, and that they are frequently present at trace levels and in complex environmental matrices. The work presented within this dissertation focuses on the development, validation, and comparison of analytical methodologies based on large-volume injection high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS) for the analysis of emerging environmental contaminants in aqueous environmental matrices. Large-volume injection (e.g. 900 μL to 4,500 μL) is an analytical technique that eliminates sample preparation associated with pre-concentration by injecting larger-than-traditional volumes of sample directly onto a HPLC column. In Chapter 2, a direct aqueous large-volume injection method was developed and validated for the quantification of natural and synthetic androgenic steroids in wastewater influent, wastewater effluent, and river water. This method was then applied to hourly composite samples of wastewater influent that were taken over the course of a single day. This work expands on the research of the endocrine-disrupting chemicals that occur in wastewater and provides an estimate of the community use/abuse of synthetic androgenic steroids. Environmental analytical methods should be as environmentally friendly as possible and efforts should be made to reduce the waste generated during analysis while maintaining analytical performance. In Chapter 3, a method based on large-volume injection was compared to two methods based on solid-phase extraction. The purpose of this comparison was to demonstrate that the same method performance could be achieved by large-volume injection as that by solid-phase extraction while reducing waste, labor, and costs. Estrogens and perfluorinated chemicals were used as model analytes and wastewater influent was used as a model matrix. The results of this study provide convincing reasons for analysts to adopt large-volume injection as an alternative to solid-phase extraction. In Chapter 4, a novel analytical method was developed and validated to quantify newly-identified and legacy fluorinated chemicals in groundwater. The final method combined micro liquid-liquid extraction, non-aqueous large-volume injection, and orthogonal chromatographic separations. Ground water samples collected from six different U.S. military bases was used to demonstrate the method. This is the first report on the occurrence of these newly-identified fluorinated chemicals in any environmental media and serves as a rational for conducting future research on their environmental fate and toxicity. The breadth of the research presented in this dissertation advances the field of environmental analytical chemistry in several areas. First, classes of environmental contaminants for which there is limited (synthetic androgenic steroids) or no (newly-identified fluorochemicals) environmental data were studied. Second, novel methods based on direct-aqueous and non-aqueous large-volume injection were developed and validated to identify and quantify those contaminants. Third, it was demonstrated that solid-phase extraction is not a "necessary evil" needed to develop methods for emerging environmental contaminants in aqueous matrices. Finally, this work is a platform on which other environmental chemists can use to develop large-volume injection methods in the future. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Aug. 2, 2012 - Feb. 2, 2013

Globally, water turbidity remains a crucial parameter in determining water quality. South Africa is largely regarded as arid and is often characterised by limited but high intensity rainfall. This characteristic renders most of the country’s water bodies turbid. Consequently, the use of turbidity as a measure of water quality is of great relevance in a South African context. Generally, turbidity alters biological and ecological characteristics of water bodies by inducing changes in among others temperature, oxygen levels and light penetration. These changes may affect aquatic life, ecosystem functioning and available water for industrial and domestic use. Siltation, a direct function of turbidity also impacts on the physical storage of dams and shortens their useful life. To date, determination of water turbidity relies on the tradition laboratory based methods that are often time consuming, expensive and labour intensive. This has increased the need for more cost effective means of determining water turbidity. In the recent past, the use of remote sensing techniques has emerged as a viable option in water quality assessment. Hyperspectral remote sensing characterizes numerous contiguous narrow bands that have great potential in water turbidity measurement. This study explored the applicability of hyperspectral data in water turbidity detection. It explored the visible and near-infrared region to select the optimal bands and indices for turbidity measurement. Using the Analytical Spectral Device (ASD) field spectroradiometer and a 2100Q portable turbidimeter, spectral reflectance and laboratory based turbidity measurements were taken from prepared turbid solutions of predetermined concentrations (i.e. 10g/l to 150g/l), respectively. The Pearson’s coefficient of correlation and R2 values were employed to select optimal spectral bands and indices. The findings showed a positive linear relationship between reflectance, the amount of soil in water and turbidity values. The strongest relationships came from bands 528, 489, 657, 1000 and 983, reporting adjusted R2 values of 0.7062, 0.7004, 0.6864, 0.7120 and 0.6961, respectively. The highest coefficient came from band 1000nm. The strongest indices were 625/440 and (770-1000)/(770+1000), with adjusted R2 values of 0.6822 and 0.6973 respectively. The use of hyperspectral data in turbidity detection is ideal for optimal band interrogation. Although good results were generated from this study, further investigations are needed in the near-infrared region. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

A water quality study was conducted on Big Duck Creek and Little Duck Creek near Elwood, Indiana during the summer, autumn and winter of 1978 - 1979 and compared to measurements made in 1938.Samples were analyzed for dissolved oxygen, biochemical oxygen demand, suspended solids, ammonia, total coliform bacteria, hydrogen ion concentration and temperature. Significant differences in concentrations were observed for each environmental parameter measured in 1979 when evaluated on a basis of sampling location. With the exception of dissolved oxygen concentrations, the effect of stream volume on the concentration of environmental parameters was in most instances small.When the up and downstream stations were compared, a definite decrease in water quality was noted. The dissolved oxygen concentrations decreased as the water flowed through the city. Due to increased organic loading, the biochemical oxygen demand increased in the downstream area.Elwood increased the suspended solids level of Big Duck Creek. Agricultural and urban runoff together with untreated sewage discharges significantly increased the suspended solids level within the inner city region. Dilution by treated sewage as well as cleaner water from Little Duck Creek help reduce the suspended solids level in the downstream location. Relatively high ammonia concentrations were observed in the upstream portions of the creeks. This was apparently related to farm practices. The higher readings of ammonia were noted after animal manure was spread on the fields along the stream. The downstream levels were also high. This was probably due to ammonia in the effluents of the sewage treatment plant. In contrast, only small changes in the hydrogen ion concentration was observed throughout the creek.The number of total coliform bacteria increased in the center of town because of a sewer bypass into the creek. Below Elwood the concentration of bacteria decreased due to dilution with disinfected effluents from the sewage treatment plant.Except for a noticeable increase in biochemical oxygen demand and ammonia, the Elwood sewage treatment plant effluent together with flow from Little Duck Creek appears to improve Big Duck Creek's condition as it leaves the city to join White River.Significant differences were observed between measurements made in 1938 and 1978 - 79. Results of the study showed a significant improvement in water quality of Big Duck Creek since 1938. This was probably due to the construction of Elwood's wastewater collection system and sewage treatment plant in the 1940s.However, there was still degradation of water quality within the city due to untreated wastewater discharges. Consequently, emphasis should be focused on the inner city problem since Elwood residents would be in the proximity to this area. / Department of Natural Resources

<p>The Eerste River is a river system which has, over the years, been subjected to human interference. The purpose of this study was to investigatge temporal and spatial trends in the water quality of the Eerste River between 1990 and 2005. The study results revealed that the major trends in the water quality of the Eerste River are more spatial than temporal.</p>