D.Phil. / Water quality management in South Africa changed drastically over the last 20 years, from focussing on effluent control to managing the water resource itself. This resulted in the promulgation of the National Water Act (Act 36 of 1998) which introduced amongst others the classification of water resources and the Reserve. The implementation of the Act is currently in process, and this requires the development of a number of "tools". One such a need is to develop a protocol to set water quality objectives for water resources that takes cognisance of both the classification and the Reserve. The move to manage water resources has also taken place in other countries such as the United Kingdom, the United States of America, The Netherlands and Australia. However, most of these countries do not have the same circumstances or the same approach to water quality management as South Africa. In most cases those countries have adopted single value water quality objectives that lead to an on/off assessment of the success of management actions that does not take full cognisance of the natural variability of water quality such as is experienced in South Africa. Water quality is not static and the effect on a user is a function of dose and exposure. In most cases users can recover from short term exposures to undesirable conditions, as long as these effects are still chronic and not acute. Water quality can therefore not be assessed by making use of a single value, but must be based on a description of the central tendency as well as extreme values. This assessment (ideal, acceptable, tolerable, unacceptable) of water quality should also be linked to management actions so that managers of water resources know where to focus the limited resources at their disposal. In this thesis a protocol is developed that can be used to determine water quality objectives that take into account the class of the water resource, as well as the Reserve. Together with this an assessment system is offered that allows managers to prioritise their actions. The protocol was applied to the Jukskei River Catchment, using data that was collected over a six year period. The protocol was found to be robust and yielded water quality objectives that can be used to focus attention on the most pressing problems. / Prof. G.J. Steyn Dr. H. H. du Preez

M.Sc. (Geography) / The Crocodile River drains a highly developed catchment, with 25% of the South African Gross Domestic Product (GDP) being produced in the Crocodile-West Marico Water Management Area (WMA). The industrial, agricultural and mining sectors that mostly contribute to GDP are however greatly dependent on the water resources within the Crocodile-West Marico WMA and therefore it is important to monitor the status of these water resources carefully. This study aimed to determine whether there is a positive correlation between changes in land-use and changes in water quality in the Crocodile River catchment area across both a spatial and temporal scale. Water quality was defined by measurement and analysis of both pure quantitative changes in water quality parameters as well as qualitative changes in water quality as related to the end use of the water. In general water quality in the study area, as measured in terms of the variables used for this study, was found to still be within acceptable range for domestic use, irrigation, livestock watering and Industrial Cat. 3 and 4 water uses. The majority of variables were however above the Aquatic Target Water Quality Range (TWQR). In terms of aquatic ecosystems, the study area is however not very sensitive with only a few catchments and sub-catchments classified as freshwater ecosystem priority areas. The freshwater ecosystem priority areas are also located in mostly the upper catchment where water quality is generally fair to good i.e. as confirmed by water quality results from Water Monitoring Stations (WMS) 90195 and 90165. It was confirmed that spatial and temporal changes in land use had a definite impact on physical and chemical water quality as measured at each WMS. The variables used to determine water quality changes due to land use change were however not ideal to determine certain land use impacts. Urban, industrial and mining impacts would for example have been easier to identify by means of metal and heavy metal concentrations as well as other toxic organic and inorganic constituents. To this extent it was a challenge to link specific industries or industrial areas to water quality changes. This was mostly due to the fact that industrial processes differ vastly, with a range of pollutants being emitted and discharged into the environment. It was however evident from the results that nutrient enrichment mostly originates from point sources, specifically Wastewater Treatment Works (WwTWs), and that salinization is mostly caused by intensive crop irrigation. Build-up or urban areas mostly resulted in lower levels of salts and dissolved solids, possibly due to limited exposed ground surfaces. It was further found that mining related to Platinum Group Metals (PGMs) resulted in and increase chloride, dissolved major salts, electrical conductivity, total hardness, potassium, magnesium, sodium and sulphate concentrations...

This study embraces two aspects of closed system culture: (a) a comparative study of four different biological filtration treatments, and (b) a quantitative determination of the nitrogen flow in a particular biological filtration system. Twenty 0,5 g juvenile Penaeus indicus Milne Edwards were cultured for approximately two months in four different kinds of sea water recirculatory systems with bacterial filtration, algal filtration, algar plus bacterial filtration and water exchange (25% every 3 days). Growth was comparable to that found in the literature for P. indicus. Nitrification occurred in all systems irrespective of the type of biological filtration employed. Ammonia, nitrite and nitrate levels were reduced by the algae, but nitrate accumulated to approximately 30 mg NO¯³ -Nℓ¯¹ in those systems without algae. Depletion of trace elements (Cu, Fe, Zn, Hn and Co) by the algae did not occur due to trace metal replenishment from the addition of food. No marked changes occurred in the concentrations of the major cations (Ca⁺⁺, Mg⁺⁺, Na⁺ and K⁺), but a small increase in Ca⁺⁺ levels was detectable in those systems with oyster shell chips in the filtration medium. Only minor changes occurred in oxygen or pH values in the various systems tested. Inorganic carbon levels showed major increases in the algal filtration systems, while a slight drop occurred in the bacterial filtration systems. The increase in the algal filtration systems was thought to be due to the formation of carbonates and bicarbonates by the reaction of respiratory CO₂ with unionized ammonia and water. Suggestions are made as to how closed systems can be improved upon. By determining the rate of excretion of P.indicus as related to size and temperature, its faecal production, and the nitrogen content of P.indicus, its food and faeces, the nitrogen flow within a system could be calculated. P.indicus was found to have an assimilation efficiency of 88,93% and a food conversion ratio of 3,49:1. Of the total dietary nitrogen input into the system, P.indicus ingested 69,02% - 19,80% of which was used for growth, 41,58% excreted and 7,64% lost as faeces. The remaining 30,98% of the total nitrogen input can be regarded as excess food nitrogen. The total nitrogen loading on the biological filtration system was found to be 80,20% of the total input of dietary nitrogen. The ability of various types of filamentous algae to remove these nitrogen compounds was determined. Suggestions are made as to the application of this information on nitrogen flow to the culture of P.indicus

A critical review of the mechanisms of present water treatment systems including, chlorination, coagulation, filtration, granular and powdered activated carbon adsorption, ozonation and ultraviolet radiation for the removal of herbicides is presented. Rapid selective and sensitive HPLC methods were developed and rigorously validated for the analysis of the selected herbicides. Analysis of atrazine was made using Cl8 cartridges. For raw water containing interferences, extraction of the compound was made on SCX cartridges, followed by solvent exchange on C18 cartridges. A quantitative recovery of virtually 100% of the compound was achieved using C18. While the double cartridge extraction of the compound gave a recovery of about 89%. Previously developed methods for 2,4-D and MCPA were rigorously validated for the extraction and analysis of 2,4-D and MCPA. A quantitative recovery of usually greater than 90% was achieved for both compounds using Cl8 cartridges. For the extraction of paraquat different extraction systems including, reversed phase on C8 and C18, ion-paired reversed phase on C18, and cation exchange on SCX, CBA, and CN were investigated. A quantitative recovery, usually greater than 90%, of the compound was obtained using CN and CBA cartridges. The methods were then successfully used for the evaluation of the removal efficiency and establishment of mechanisms of removal of herbicides by biological filters at bench and pilot scale. Four herbicides belonging to three broad chemical categories were studied. The data presented in this study demonstrated that biological filters are very efficient in removing certain classes of herbicides. 2,4-D and MCPA were consistently removed to below a detection limit of 0.1 mug/1 for an influent concentration of 3-11 mug/1. Process variables such as flow rate, bed depth and contact time were investigated for the efficient removal of these herbicides. Seasonal variations in performance were observed and possible explanations proposed. A series of experiments was undertaken to establish .mechanisms of removal. Quantitative recovery of the herbicides from the river water proved that the processes in the filter bed as opposed to the processes in the water were responsible for removal of the herbicides. It was clear from the investigation of the adsorption of the herbicides both on the sand and organic and inorganic dirt that adsorption on these surfaces was not the main reason for removal. Filter maturation experiment showed that the presence of microorganisms in the bed is a precondition for the removal of herbicides. A depth experiment for the removal of 2,4-D showed that superficial efficient zone of removal imitates the distribution of microbial density. This evidence confirms the significance of microorganisms for the removal of herbicides by the filter bed. The ultimate proof of the biodegradation of 2,4-D by microorganisms in the filter bed was the identification of the biodegradation product 2-chlorophenol as predicted by the metabolic pathways of the compound. Filter design modifications using activated carbon were made to accommodate the removal of 'non-biodegradable' herbicides. A sandwich sand / GAC / sand filter was investigated. Filter efficiency for this arrangement was determined and short-comings were identified and a possible solution in the form of a double GAC sandwich is suggested.

The natural condition of the Orange River should be evaluated in order to develop baseline information so that it can be used for comparison, monitoring and informed decision-making. This will also allow for further research to take place. Although there is a lot of data available on the Orange River, little work has been done on the evaluation of the natural conditions that influence the inorganic water chemistry Inorganic data, from 1986 to 2006, obtained from the Department of Water Affairs and Forestry (DWAF) was evaluated for six sample stations along the Orange River (D1H009Q01, D3H008Q01, D3H012Q01, D3H013Q01, D7H008Q01 and D7H005Q01). Climate data (1986-2006) was obtained from the South African Weather Service. The following water quality data was used in the evaluation: pH and the concentrations of major elements (all in mg/L). The major elements include sodium (Na ), potassium (K ), calcium (Ca ), magnesium (Mg ), silica (Si ), fluoride (F ), orthophosphate (PO ), chloride (Cl ), total alkalinity (TAL) assumed to be bicarbonate (HCO ), sulphate (SO ), nitrate (NO ) (assuming that NO >>> NO ) and the total dissolved solids (TDS). Various geochemical techniques were used to analyse the data. The results of this study show that the water chemistry of the Orange River is controlled by: 1. Chemical weathering of siliceous sediment, intrusive igneous rocks and metamorphic rocks (Na , K , Mg , Ca , HCO , F and Si ). 2. Input from agricultural and urban activities affecting, in particular, the concentrations of PO , NO , SO and Cl . There is an increase in cation and anion concentrations from 1986-2006. The concentration of cations and anions increases downstream from D1H009Q01 to D7H005Q01 i.e. from a colder wetter climate to a drier hotter climate. Based on the chemical characteristics, two groups were identified. The stations in each group include: Group 1: D1H009Q01, D3H013Q01, D3H012Q01 and D3H008Q01 and Group 2: D7H008Q01 and D7H005Q01. For group 1 the degree of pollution is generally consistent (between 10 and 30 percent). The element concentration was plotted against the total annual runoff and the visual trend shows a decrease in Na , K , Mg , Ca , HCO and F as the annual runoff increases. This is because the dilution effect is stronger than the release of cations and anions due to chemical weathering. This decrease is typical for weathering of rock types such as granites, shale and metamorphic rocks. Si shows an increase in concentration as total annual runoff increases. This indicates that feldspar is the dominant mineral that is being weathered. Chemical weathering of feldspars (specifically Na- and K-feldspars) releases more Si compared to other species. PO and SO show no visual trend and Cl and NO show a possible increase in concentration with an increase in total annual runoff. This is most likely due to greater input of these species from the surrounding agricultural and urban areas when the runoff increases. For group 2 the degree of pollution is generally higher and shows a greater fluctuation compared to group 1. The visual trend for the concentration of Na , K , Mg , Ca , Cl , SO , HCO and F shows a sharp decline at low runoff, dilution is the dominant process. The concentration of these then increases as chemical weathering becomes more dominant, the effect of chemical weathering becomes greater than the effect of dilution. After this the effect of dilution becomes greater and the species concentrations show a steady, slight decrease, similar to group 1. Si shows a sharp increase as total annual runoff increases to 5000 million m3, thereafter it decreases slightly. The increase of the Si concentration is due to chemical weathering which is stronger than the dilution effect. The increase in NO and PO is most likely due to agricultural activities and urbanisation in the immediate area. As surface runoff increases it increases transport of these chemical species into the river. Both the agricultural/urban input and the release of cations and anions by chemical weathering are severely influenced by the stream runoff. Any evaluation of the inorganic chemistry from the Orange River should include runoff. The variation of the annual runoff affects the percentage of pollution, especially for the lower Orange River. / Prof. J.M. Huizenga

This study assessed the pathogenicity of source waters in the Nwanedi River catchment surface waters including rivers as well as its related non perennial tributaries (storm run-off) by determining the presence of diarrhoeagenic Escherichia coli pathotypes namely Enteropathogenic Escherichia coli, Enterotoxigenic Escherichia coli, Enterohaemorrhagic Escherichia coli, Enteroaggregative Escherichia coli and Enteroinvasive Escherichia coli. The faecal pollution levels in the surface waters was assessed by measuring indicator Escherichia coli numbers in water samples at various sampling sites carried from its land-based faecal sources into the receiving surface water bodies. Sampling sites were selected to represent the human, livestock as well as wildlife sources of faecal generation and the possible infection risk posed to domestic, full body contact, agriculture uses as well as for abstraction intended for drinking were determined by comparing the Escherichia coli numbers with the guidelines summarised in Table 2.6: Chapter 2. A total of 199 proposed water samples were collected and analysed by the Miniaturised Most Probable Numbers method using 96-well micro-titre plates to enumerate Escherichia coli from the water samples. Twenty eight of 199 water samples were also analysed with a multiplex polymerase chain reaction using specific primers for the identification of diarrhoeagenic Escherichia coli related virulent genes namely – Mdh for commensal E. coli, Eagg and pCVD for Enteroaggregative E. coli, ST1 and LT1 for Enterotoxigenic E. coli, Stx1 and Stx2 for Enterohaemorrhaegic E. coli, EaeA for Enteropathogenic E. coli and Enterohaemorrhagic E. coli, Ial for Enteroinvasive E. coli. River water samples were directly filtered and 100-mℓ of filtered water samples were extracted while 1-mℓ pre-cultured Escherichia coli from storm run-off samples were extracted for use in the multiplex polymerase chain reaction. Because of the villages along the Nwanedi River catchment, Enteropathogenic E. coli followed by Enterotoxigenic E. coli was suspected to be the dominant diarrhoeagenic Escherichia coli. Contrary to this Enteroaggregative E. coli (54%) was dominant followed by Enterohaemorrhaegic E. coli (29%), Enteroinvasive E. coli (7%), Enteropathogenic E. coli (4%) and Enterotoxigenic E. coli (4%) respectively, in the surface water samples. The Escherichia coli numbers were significantly higher in storm run-off compared to the river water samples. Literature report Enteroaggregative E. coli to be associated with diarrhoea in HIV/AIDS patients, to whom its dominance in the surface water samples could pose serious infection risk to the Nwanedi River catchment communities, more especially the young, elderly and the immuno-compromised at the period of sampling if the waters are used untreated. The high Escherichia coli numbers could possibly be the results of continuous faecal contamination into the water sources and the rain storm events carrying faecal materials from land surface. Results show that Nwanedi River catchment waters harbour pathogens indicated by diarrhoeagenic Escherichia coli occurrence as well as commensal Escherichia coli numbers , which suggest the possible infection risk posed to the consumers if the waters are used untreated. / Prof. P. Jagals Dr. T.G. Barnard

>Magister Scientiae - MSc / In the Otjozondjupa Region, Namibia, water is transferred from Swakoppoort and Omatako Dams into Von Bach Dam to limit evaporation losses and bring water closer to the purification plant. There is a gap in the knowledge about the effects on water quality in Von Bach Dam due to water transfer from Swakoppoort and Omatako Dams, as previous studies on such aspects in the area do not exist. The study objective was to; (a) characterise water quality of the three dams, (b) determine whether water transfers affect the water quality of Von Bach Dam, (c) determine if the treatment of water abstracted from Von Bach Dam for potable water supply has been influenced by water quality changes arising from water transfers. Four sampling locations were established in Von Bach Dam, one in Swakoppoort Dam, and one in Omatako Dam. Water samples were collected in these three dams weekly. Two senior officers responsible for water treatment were interviewed about possible water treatment problems arising from the water transfer. Descriptive statistics, ANOVA and correlation were carried out to analyse the data. The results showed that, secchi disk depths, total phosphorus, orthophosphate, ammonia, dissolved organic carbon, chlorophyll a and microcystis were statistically different in the three dams at a 5% significance level. Upstream land uses, geology of the catchment and water stratification are likely to influence the water quality in the three dams. During water transfers into Von Bach Dam, secchi disk depths, turbidity, dissolved oxygen, iron, total phosphorus, ammonia (NH₄-N) and chlorophyll a were statistically different at a 5% significance level at all the four sampling locations within this dam. These differences are due to the influence of water transfers. The influence of water transfers on water quality was localised at the discharge points SL4 (at the inflow of Von Bach Dam) and SL1 (at the outflow of Von Bach Dam). Water treatment problems due to high ammonia, dissolved organic carbon, and turbidity in the water abstracted from Von Bach Dam occurred during water transfers and runoff from the catchment. This view was supported by the study findings.

β-N-methylamino-L-alanine (BMAA) is a non-proteinogenic amino acid associated with human neurodegenerative diseases. The content of BMAA in cyanobacteria is modulated by nitrogen in laboratory cultures. In order to evaluate the potential for human exposure, the nitrogen modulation of BMAA content needed verification in a natural environment. In accordance with laboratory culture studies, data presented in this study show that combined nitrogen was the most significant modulator of both cellular microcystin (MC) and BMAA content in phytoplankton in an environmental cyanobacterial bloom. While BMAA is produced upon nitrogen deprivation, MC is only produced at a specific nitrogen threshold where the rate of increase of nitrogen in the cell exceeds the carbon fixation rate. As BMAA and MC were detected in phytoplankton sourced from the Hartbeespoort Dam reservoir, the transfer of these cyanotoxins to organisms of higher trophic levels was investigated. Both BMAA and MC were detected at high concentrations in the liver and muscle tissue of fish sourced from the Hartbeespoort Dam reservoir indicating that consumption of fish from this reservoir constitutes a serious risk of exposure to cyanotoxins. In addition to the dietary exposure route to BMAA, two recent studies reported a correlation between Amyotrophic Lateral Sclerosis (ALS) incidence and the potential for aerosol exposure to cyanobacteria. With the absence of any evidence of the systemic distribution of BMAA following inhalation, an evaluation of the potential exposure risk associated with living in close proximity to this reservoir was deemed premature. A laboratory experiment investigating the effect and systemic fate of inhaled aerosolised BMAA was therefore conducted in order to determine the feasibility of inhalation as a potential BMAA exposure route. Data from the rat inhalation exposure study, however, showed that in rats BMAA inhalation may not constitute a significant mechanism of toxicity at environmental BMAA levels.

The focus of this study is the hydrochemical variability of runoff events in two nested alpine/sub-alpine basins. More specifically, the aim is to link hydrograph interpretations to results of hydrochemistry during rain storms in order to understand better short term hydrochemical fluxes and variability in solute sources. Hydrograph separation was undertaken by using four hydrological tracers; electrical conductivity, concentration of silica, and the stable environmental isotopes oxygen-18 and deuterium. The different methods predicted consistent high pre-storm water contribution for the lower station at peak flow (60%-90%) but less consistent results were found at the upper basin outlet (25%-90%). The chemical characteristics of the stream water have been analyzed using three different approaches, namely; statistical, mass balance, and thermodynamic. Linear correlation was used to investigate the statistical association between discharge and the individual chemical species. The mass balance approach was used to correlate stoichiometry of the bedrock mineralogy to dissolved constituents in the stream water. Finally, a thermodynamic technique was used to evaluate to what extent the stream water could be represented as an equilibrium system and how this changed over the course of the storm. The results from these methods showed that the stream water variability was caused almost entirely by dilution from rain water input. / Arts, Faculty of / Geography, Department of / Graduate

The primary objective of this study was to evaluate quantitatively the effects of a mixture of agricultural and non-agricultural land use practices on the chemical characteristics of the Salmon River, near Fort Langley, B.C. Present land use and geomorphic unit maps were used to determine appropriate stream sampling sites which would give an indication of the combined and separate effects of land use and geologic materials on water quality. Chemical characteristics of the Salmon River and its tributaries were monitored over a 10 month period from May 1974 until April 1975. Eighteen chemical variables were analyzed in the laboratory using Standard Methods and 5 were monitored in the field. The in situ parameters included pH, temperature, oxidation-reduction potential, specific conductance and dissolved oxygen levels. Also monitored were 7 trace metals, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Atmospheric precipitation collectors were installed at the end of June 1974 and precipitation samples collected monthly from July 1974 until April 1975. Eighteen separate chemical variables were monitored at these sites using standard methods. Stream bed sediment grab samples were taken in May and again in July 1974. These_ samples were analyzed for total elemental composition as well as total nitrogen, total carbon, total sulfur, total cation exchange capacity, exchangeable cations (Ca, Mg, Na, K) and pH. The major geologic materials in the watershed were sampled in 6 sites located in undisturbed and cultivated areas on marine, glacial outwash, and alluvial materials. The monitoring of some selected chemical characteristics of the Salmon River revealed in general the mean values of pH, specific conductivity, temperature, total alkalinity, total HC03 alkalinity, total hardness (CaCO₃ equivalent), total dissolved solids, total Kjeldahl N, organic C, NO₃ -N, CI, Na, and K were consistently higher at low streamflows than at high (>750cfs) streamflows. Oxidation reduction potential and dissolved oxygen mean values were consistently higher at high flows than at low flows. The other variables measured remained relatively constant on average across all levels of streamflow. There was, however, considerable variation at specific point samples. Data derived from collection of atmospheric precipitation indicated a significant input of many chemical factors to the watershed. Bed sediment and soils chemical characteristics give a general indication of the amounts and distribution of the various chemicals potentially available for contribution to stream waters. Analysis of the results obtained in comparison with water quality standard acceptable levels revealed water quality problems with pH, temperature, phosphorus, iron, copper, and manganese. Significant statistical correlation exists between water quality variables and glaciomarine, marine and beach overlying marine or glaciomarine materials; glacial outwash materials; agricultural field crops; low density residential areas; and schools. In order to identify specific point and non-point sources more detailed information is needed on groundwater characteristics and the streamflow characteristics of tributary streams. Some general management alternatives are recommended bearing in mind that each site must be evaluated on its own merits and specific suggestions made on-site. / Land and Food Systems, Faculty of / Graduate