Microbial pollution of surface waters and coastal zones is one of the foremost challenges facing the water industry and regulatory authorities. Yet despite the concern and increasing pressures on water resources in both developed and developing countries, understanding of microbial pollutants in the aquatic environment is fairly scattered. There is a need for an improved ability to quantify the processes that control the fate and distribution of enteric organisms to support decision - making and risk management activities. The aim of this thesis has been to advance the understanding of the dynamics of microbial pollution in aquatic systems through review, experimentation and numerical modelling. Initially, a new module for simulating the protozoan pathogen, Cryptosporidium, was developed and implemented within a three - dimensional ( 3D ) coupled hydrodynamic - water quality model ( ELCOMCAEDYM ). The coupled 3D model was validated against a comprehensive dataset collected in Myponga Reservoir ( South Australia ), and without calibration, performed to a high degree of accuracy. The investigation then sought to examine the experimental dataset in more detail and found a significant difference between protozoan pathogens and the bacterial and viral indicators. To examine the role of bacterial association with particles in more detail, a second experimental campaign was carried out in Sugarloaf Reservoir ( Victoria ). This campaign was used to gain insights into the association of coliform bacteria with suspended sediment and to quantify their sedimentation dynamics based on in situ measurements. Using an inverse technique, particle profile data was used to create a simple Lagrangian model that was applied to back - calculate the sedimentation rates of the coliform bacteria and the fraction that were attached to the particles. The results indicated that 80 - 100 % were associated with a small - sized clay fraction. This result was in contrast with the Cryptosporidium dynamics in Myponga Reservoir, where it was concluded that oocysts did not settle with the inorganic particles. These findings indicated the current models for simulating the array of organisms of interest to regulatory authorities are inadequate to resolve the level of detail necessary for useful predictions and risk management. Large differences between the protozoa, bacteria and phages were being observed due to different particle association rates and sedimentation dynamics, order of magnitude differences in natural mortality rates, and different sensitivity to sunlight bandwidths. The original model implemented within CAEDYM was therefore rewritten to be more complete and generic for all microbial pollutants and different types of aquatic systems. The model was built using a generic set of parameterizations that describe the dynamics of most protozoan, bacterial and viral organisms of interest. The parameterizations dynamically account for sensitivities to environmental conditions, including temperature, salinity, pH, dissolved oxygen, sunlight, nutrients and turbidity, on the growth and mortality of enteric organisms. The new model significantly advances previous studies in several areas. First, inclusion of the growth term allows for simulation of organisms in warm, nutrient rich environments, where typical die - off models tend to over - predict loss rates. Second, the natural mortality term has been extended to independently account for the effects of salinity and pH, in addition to temperature. The salinity - mediated mortality has also been adapted to account for the nutrient status of the medium to simulate the importance of nutrient starvation on the ability of an organism to survive under osmotic stress. Third, a new model for sunlight - mediated mortality is presented that differentially accounts for mortality induced through exposure to visible, UV - A and UV - B bandwidths. The new expression has capacity to simulate the photo - oxidative and photo - biological mechanisms of inactivation through included sensitivities to dissolved oxygen and pH. Fourth, the model allows for organisms to be split between free and attached pools, and sedimented organisms may become resuspended in response to high shear stress events at the water - sediment interface caused by high velocities or wind - wave action. Fifth, the enteric organism module has been implemented within the bio - geochemical model CAEDYM, thereby giving it access to dynamically calculated concentrations of dissolved oxygen, organic carbon, and suspended solids, in addition to pH, shear stress and light climate information. Without adjustment of the literature derived parameter values, the new model was validated against a range of microbial data from three reservoirs that differed in their climatic zone, trophic status and operation. The simulations in conjunction with the experimental data highlighted the large spatial and temporal variability in processes that control the fate and distribution of enteric organisms. Additionally, large differences between species originate from variable rates of growth, mortality and sedimentation and it is emphasized that the use of surrogates for quantifying risk is problematic. The model can be used to help design targeted monitoring programs, examine differences between species and the appropriateness of surrogate indicators, and to support management and real - time decision - making. Areas where insufficient data and understanding exist are also discussed. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2007.

published_or_final_version / Botany / Master / Master of Philosophy

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

M. Tech. Water Care. / Aims determining whether inadequate treatment of wastewater and the faecal pollution load of effluents and receiving water bodies in Sedibeng District and Soshanguve peri-urban area of Tshwane Metropolitan Municipality were a function of population growth. To achieve the aim of this study, the following objectives were pursued: Assess the variation in nutrient load and compliance of the physicochemical quality of effluents and receiving water bodies in terms of the South African and World Health Organization standards. Furthermore, the water quality index was also used to assess the overall physicochemical quality status of effluent and receiving water bodies. Assess the compliance of the microbial quality of effluents of the four wastewater treatment plants and their respective receiving water bodies in terms of the South African and World Health Organization limits. Determine the prevalence of Salmonella Typhimurium, Shigella dysenteriae and Vibrio cholerae in the targeted wastewater treatment works effluent and their respective receiving water bodies. Determine the possible public health risks of Escherichia coli, Salmonella Typhimurium, Shigella dysenteriae and Vibrio cholerae infections that could be acquired due to ingestion of or exposure to untreated water from the targeted receiving water bodies. Capture information regarding population growth and wastewater treatment plants in Sedibeng District and Soshanguve peri-urban area of Tshwane Metropolitan Municipality and determine whether under performance of the targeted wastewater treatment works could be attributed to population growth.

This thesis concerns groundwater quality with a detailed study of the Abbotsford-Sumas Aquifer and the high nitrate-nitrogen values that have been occurring for the past 20 or so years. Groundwater is becoming an increasingly scarce resource, both in terms of quantity and quality, worldwide. Aquifers are generally poorly understood, dynamic and are an integral part of the hydrological cycle. Aquifer contamination by land use activities threatens their utility as potable sources of water. The literature suggests that one useful measure of the effects of land use on water contamination is nitrate-nitrogen. This substance may be traced to such activities as agricultural practices and septic systems, two major concerns in the area above the Abbotsford-Sumas Aquifer in southwestern British Columbia. The Abbotsford-Sumas Aquifer was examined in detail with a review of the history, geology, hydrogeology, stakeholders, groundwater use and the current identified contamination. Based on the hydrogeology and land use of the aquifer, a representative study area was selected as a case study. With a focus on nitrate-nitrogen the principle objectives were: to determine land use effects on groundwater contamination, assess the contributions of various nitrogen sources and assess the overall impact of intensive land use on the groundwater contamination. This was investigated by a temporal land use evaluation, a nitrogen / nitrate balance and a review of water quality changes. The major land use change in the study area over the period 1969 to 1992 has been the increase in land used for raspberry production which now accounts for over half of the study area. The nitrogen balance revealed a large quantity of nitrogen unaccounted for which is potentially available for leaching. The predominate source of this excess nitrogen is attributed to the high levels of poultry manure fertilizer applied to the soils supporting raspberry crops. Calculations of the nitrogen sources suggest over 90 percent of the excess nitrogen comes from this source. This was well above the other nitrogen sources such as mineralisation, aerial deposition, septic systems, corn crops and pasture land. Although a minor overall nitrogen source, septic tanks appeared to have the potential for high local loadings of nitrate-nitrogen. The water quality data showed increases in nitrate-nitrogen concentrations in the groundwater over the last 40 years. Seventy percent of the water samples showed nitrate-nitrogen values above the Canadian Drinking Water Guideline maximum value allowed in drinking water. The data however displayed significant variability.

The Umdloti River is relatively small but very important system that is located northeast of central Durban. This river flows pass the coastal town of Verulam and finally into an open/closed estuary, the La Mercy estuary. This fluvial system has a concrete gravity dam that is built in the upper reaches, the Hazelmere Dam, which supplies water to the north local council and surrounding districts under the supervision of Umgeni Water. The river is characterized by human activities, especially urbanisation and industrialization in the middle reaches and intensive agriculture (vegetables, sugar cane and banana plantations) along the catchment. The influence of anthropogenic factors within this catchment results from the dam construction, informal settlements, both commercial and subsistence agriculture, intensive industrial activity, accelerated urban developments, and recreational uses. Consequently there has been considerable concern regarding the impacts of these factors together with natural influences on the water quality and health status of this fluvial system. In this study water samples were taken and analysed for the following variables: nitrites; nitrates; ammonia; pH; Escherichia coli; sulphate; phosphate; total dissolved solids; chemical oxygen demand; biological oxygen demand; calcium and magnesium. The results indicate that the middle and the lower reaches of the Umdloti River are most impacted. Further, results from a questionnaire survey indicate that natural and human induced impacts have impacted negatively on the health status of the Umdloti River. The questionnaire survey also revealed that respondents benefited positively from the construction of the dam whilst the expropriation of land for the construction of the dam itself created much resentment to the prior land owners. The water quality data and the questionnaire analysis indicate overall natural and human induced impacts have had negative effects on the Umdloti River and the La Mercy estuary. It is necessary that local municipal authorities introduce corrective catchment management practices (outlined in the final chapter of the study) to enhance the water quality and health status of the river. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2009.

No description available.

1 examined the temporal and spatial distribution of total ammonia nitrogen (TAN) and un-ionized ammonia (NH,) in sediment pore water and compared the temporal and spatial patterns of TAN and NH, in overlying surface water with those in pore water, to determine if they were reaching concentrations known to be deleterious to fingernail clams. Pore water was obtained by core extraction and subsequent centrifugation. TAN and NI-I3 in pore water were measured from May through December 1994, at ninety two sites in pool 8, upper Mississippi River, to a depth of five centimeters below the sediment-water interface. TAN and NH3 in pore water were significantly different among sampling dates; with the greatest concentrations occurring in the summer months. Tan and N1-I3 in pore water was significantly greater in impounded open water and backwater side channel habitats and least in main channel border habitat. Tan and NH3 in surface water were significantly less than those in pore water from all of the habitats studied. Analysis of sediment substrate physical features, found that fingernail clam density and occupance were correlated to texture, with fingernail clams preferring silt loam and loam textures. Analysis of the data determined fingernail clams have a preference for particular water depths. It was found that a positive correlation exists between the occurrence and abundance of may flies and fingernail clams. Additionally, this study found a positive correlation between the density of dead fingernail clams (as per empty shells) and the abundance of live fingernail clams. Sites that contained a mean NI-I, concentration below 36 ug/L possessed the largest numbers of fingernail clams. When the mean un-ionized ammonia was above 36 ug/l, fingernail clam density declined precipitously-- 36 ug/L NH3 is the concentration demonstrated to inhibit growth of fingernail clams in laboratory studies. Mean concentrations of NH, in pore water at sites containing fingernail clams was 40 ug/L and ranged from 3 to 100 ug/L. At sites where fingernail clams were nonexistent, NH3 ranged from 3 to 375 ug/L with a mean of 57 ugfL. Mean un-ionized ammonia concentrations at sites containing fingernail clams were significantly different from and consistently lower than sites without fingernail clams. / Department of Natural Resources and Environmental Management

Even though the necessity of water quality monitoring systems is increasing, and though mobile watery quality monitoring systems using the combination of automatic measuring devices and autonomous vehicles is becoming available, research on effective deployment of such systems is not studied well. The locations or paths to take the measurement are one of the most important design factors to maximize the performance of water quality monitoring systems, and they needs to be optimized to maximize the monitoring performance. To solve these optimization problems, multi-objective genetic algorithms were proposed and developed. The proposed optimization procedures were applied to hypothetical circular lakes and Lake Pontchartrain in order to obtain optimal monitoring locations, straight monitoring paths, and higher-order monitoring paths under various conditions. Also, the effect of various parameters such as the speed of a monitoring vessel, the weights of possible scenarios, and etc. are investigated. The optimization models found optimal solutions efficiently while reflecting various effects of complex physical settings. The results from the optimizations show that distribution of possible source locations is an important factor that affects optimal solutions greatly. In a closed water body, wind is major forcing that determines hydrodynamics and contaminant transport, and it affects optimal solutions as well. Straight monitoring lines do not perform very well due to their incapability to cover the irregular boundaries of water bodies. Higher-order optimal monitoring paths overcome this difficulty and perform well up to a comparable level of a few stationary monitoring locations even under realistic and transient conditions.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 84-94).