Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 98-108). Also available on the World Wide Web.

Thesis (M. Sc. (Environmental Science))--Rhodes University, 2005.

Thesis (M.S.)--Eastern Illinois University, 2009. / Includes bibliographical references (leaves 65-72).

Thesis (Ph. D.)--University of Alabama at Birmingham, 2006. / Description based on contents viewed Jan. 26, 2007; title from title screen. Includes bibliographical references (p. 98-105).

No description available.

M.Sc. / This dissertation establishes the present – day condition of the Hennops River in terms of its water quality and hydrological status. The Hennops River is situated between Johannesburg and Pretoria within the provincial boundaries of Gauteng. The province has a high population density and is regarded as the economic powerhouse of South Africa. As such, rivers flowing through Gauteng have become polluted by the different land uses and activities present in the province. The Hennops River itself has lost most of its aesthetic appeal and has become less useful for recreational and agricultural uses. Furthermore, the Hennops River has become a liability and concern in suburbs south of Pretoria and, more importantly, has become less suitable for sustaining aquatic ecosystems in some of its sections. The Hennops River, therefore, has an effect not only on the environment itself, but also in terms of social and economic aspects. Because of these concerns it was deemed necessary to determine the actual water quality conditions and associated problems prevailing in the Hennops River. Being fed by tributaries, these problems could not be overlooked and were also included in this study. In order to achieve the aim of the study a literature review concerning the concept of water quality and the different physical and chemical constituents affecting aquatic ecosystems needed to be conducted. Added to this, attention had to be given to the study area’s physical features and land uses having an effect on the catchment’s water quality and associated problems. A literature review on existing knowledge of the Hennops River and its principal tributaries was also conducted so that it could be determined whether these rivers have deteriorated over the past three decades. The most recent water quality data was not only compared against existing knowledge, but also in terms of the Target Water Quality Range for Aquatic Ecosystems as stipulated by the Department of Water Affairs and Forestry. This study showed that deterioration of the Hennops River has occurred since rapid urbanisation within its catchment started during the 1970’s. Most of the River’s water quality and associated problems can be ascribed to problems occurring further upstream in the form of the Kaalspruit and Olifantspruit flowing through formal and informal settlements, industrial areas and agricultural land. The water quality of these rivers and the upper Hennops River is the least suitable of the whole study area for aquatic ecosystem well-being. Not only is this a concern but additional hydrological problems occur as well. These include problems such as erosional activity of riverbeds and riverbanks and the silting-up of Centurion Lake. An urgent need exists for holistic catchment management and rehabilitative measures to be implemented to improve the ecological state of these rivers. Rehabilitative measures were proposed and are aimed at improving the water quality and associated problems of the Hennops River and its affected tributaries. It is concluded, therefore, that the status of the Hennops River is not going to improve without the implementation of rehabilitative measures that should form part of an environmental management plan.

Faecal contamination in water is detected using appropriate microbial models such as total coliforms, faecal coliforms and E. coli. Βeta-D-Galactosidase (β-GAL) and Beta-D-glucuronidase (β-GUD) are two marker enzymes that are used to test for the presence of total coliforms and E. coli in water samples, respectively. Various assay methods have been developed using chromogenic and fluorogenic substrates. In this study, the chromogenic substrates chlorophenol red β-D-galactopyranoside (CPRG) for β-GAL and p-nitrophenyl-β-D-galactopyranoside (PNPG) for β-GUD were used. Potential problems associated with this approach include interference from other organisms present in the environment (e.g. plants, algae and other bacteria), as well as the presence of certain chemicals, such as phenolic compounds in water. Phenolic compounds are present in the aquatic environment due to their extensive industrial applications. The USA Enviromental Protection Agency (EPA) lists 11 Priority Pollutant Phenols (PPP) due to their high level of toxicity. This study investigated the interfering effects of the eleven PPP found in water on the enzyme activities of both the β-GAL and β-GUD enzyme assays. The presence of these PPP in the β-GAL and β-GUD enzyme assays showed that over and underestimation of activity may occur due to inhibition or activation of these enzymes. Three types of inhibition to enzyme activities were identified from double reciprocal Lineweaver-Burk plots. The inhibition constants (Ki) were determined for all inhibitory phenolic compounds from appropriate secondary plots. Furthermore, this study presented a validated reverse phase high performance liquid chromatography (RP-HPLC) method, developed for the simultaneous detection, separation and determination of all eleven phenolic compounds found in the environment. This method demonstrated good linearity, reproducibility, accuracy and sensitivity. Environmental water samples were collected from rivers, streams, industrial sites and wastewater treatment plant effluent. These samples were extracted and concentrated using a solid phase extraction (SPE) procedure prior to analysis employing the newly developed HPLC method in this study. Seasonal variations on the presence of the PPP in the environment were observed at certain collection sites. The concentrations found were between 0.033 μg/ml for 2,4-dinitrophenol in a running stream to 0.890 mg/ml for pentachlorophenol from an tannery industrial site. These concentrations of phenolic compounds found in these environments were able to interfere with the β-GAL and β-GUD enzyme assays.

M.Sc. (Zoology) / The construction of the Pongolapoort Dam in 1974 has altered conditions downstream of the Phongolo River in terms of hydrology, geomorphology, water quality, and ecosystem services. Activities along the Phongolo River permit anthropogenic compounds such as pesticides used in disease control to enter the aquatic environment. This alteration of natural environmental conditions creates a need for a monitoring programme. This study aims to assess the use of Hydrocynus vittatus as an indicator organism of pollution in the Nyamithi Pan and Phongolo River. Water and sediment samples were analysed for a variety of metal elements. The physical characteristics of water samples were determined using a WTW Multi 340i multimeter. Nutrients in water were analysed using a Merck Spectroquant™ Pharo 100 Spectrophotometer. Sediment analysis was based on the standard protocols of the United States Environmental Protection Agency (2001). Physiological stress responses in Hydrocynus vittatus were determined using acetylcholine esterase, catalase, cellular energy allocation, 7-ethoxyresorufin-O-deethylase, malondialdehyde, metallothionein, superoxide dismutase, and protein carbonyls. Employing standard techniques H. vittatus was analysed for metals and organics using ICP-MS, ICP-GS and ICP-OES. Results for biological responses and bioaccumulation show significant differences between sites related to the environmental concentrations of elements. Organisms in the Phongolo River have elevated concentrations of DDT and the metabolites indicating recent exposure. Organisms from the Phongolo River are seen to be responding based on up or down regulated concentrations of biological markers. In particular, concentrations of CAT, MDA and PC are elevated in the Phongolo population with decreased AChE responses indicating toxicant exposure. Data accumulated in this study will contribute to the establishment of baseline chemical, physical and biological knowledge of the effects of contamination in South African waters.

M.Sc. / Mpumalanga, “the place where the sun rises”, sets the scene for one of the rarest wetland types in South Africa. They are formed on one of the last remnants of the ancient African land surface, contain peat and together with a variety of other pan types make up the Mpumalanga Lakes District. Of these approximately 320 pans, only ±2.3% are reed pans. These endorheic wetlands are unique from other pan types and peatlands in South Africa and support an abundant biodiversity. They perform vital functions such as water storage, filtering out impurities and carbon fixation, which prevents an excess release of CO2 into the atmosphere. There is very little known about these endorheic wetlands and thus they are constantly being threatened by various activities such as agriculture, livestock and mining. The objectives of this study were to determine the spatial and temporal variation of macroinvertebrate community structures of reed pans and the environmental factors, such as water quality, responsible for the maintenance of these structures; to determine the best method for sampling aquatic invertebrates in reed pans; as well as to determine the relationship between aquatic invertebrates and the water, sediment and habitat quality of a reed pan. Together with this the amphibian diversity as well as the occurrence of other biotic components was determined. Four reed pans were assessed during four different seasons over a one year period to account for the different hydrological extremes. Sub-surface water samples were analyzed for their suspended solid content, nutrient levels, metals and chlorophyll-a concentrations as well as in situ water quality parameters. Sediment samples were analyzed for metal concentrations, organic carbon and water content, as well as sediment size distribution. Invertebrates were collected using the following sampling techniques: aquatic light trap, terrestrial light trap, emergent trap, sweep net, plankton net, as well as benthic sampling using an Eckman grab.

The Department of Water Affairs and Forestry (DW AF) is the custodian of South Africa's water resources and its primary role is to maintain the fitness for use of water on a sustained basis. DW AF recognized that management and assessment of fitness for use can only be based on reliable monitoring data. For this purpose DWAF has already for a number of years operated a national programme which collects data on the chemical and physical quality of South Africa's water resources. The microbial quality of surface water is of growing concern in a number of areas in South Africa. Water of poor microbial quality has serious implications for domestic, recreational and agricultural use due to the risk of water-borne diseases. DW AF acknowledged the need for information on the microbial quality of South Africa's water resources to assess and manage the potential health risk to water users. As an initial step the development of a national microbial monitoring programme to assess the faecal pollution of surface waters was initiated. This study describes the development of the conceptual design of such a programme and demonstrates how a novel area prioritization procedure enhanced the design. The focus of the programme was to be areas where human health might be severely impacted by the microbial quality of surface water. To identify such areas, a procedure for the identification and prioritization of specific areas of concern was developed and used as part of the design approach. Two factors were identified for the quantification of the potential health risk. They were the threat of microbial pollution of water (the result ofland use) and the exposure of consumers to the water (sensitivity of water uses). A number of land and water uses information sources therefore served as the basis for determining priority among the different areas. The described approach to identify and prioritize specific areas of concern has a number of benefits. Primarily, the approach assists in focusing the monitoring efforts on problem areas without a need for extensive historical microbial water quality data. The approach could be used to optimize the spatial distribution of sampling stations and assist in determining their national distribution. The approach also allows for phased implementation of the programme which facilitates the development of skills and capacity, as well as required infrastructure needed for the large scale operation of the programme. The approach to focus on impacted areas is generic enough not to be restricted to the design of microbial water quality monitoring systems. Other monitoring objectives could also be dealt with in the same manner. During evaluation of the design on a pilot scale the conceptual design was found to meet the set information objectives. The conceptual design for the programme also deals effectively with constraints and changes in the external environment in which it has to operate. Implementation of the national programme has started and plans to expand the programme are progressing well. The concept of high risk areas and the procedure to identify and prioritize such areas as developed during this study is a critical component of the overall design. The programme appears to address a significant information need on an important aspect of water resources management and to do so in an efficient and effective manner. / Thesis (PhD (Water Resource Management))--University of Pretoria, 2005. / Microbiology and Plant Pathology / unrestricted