A thorough biological survey and evaluation is a lengthy and expensive project. The number of technically trained persons required prevent its use by most public agencies. Since public health departments are the groups most frequently concerned with measuring the effects of pollution in streams, a need exists for a simplified method of sanitary survey. Recognizing this need, the Texas Health Department assigned the writer the problem of devising a method of survey which would require a field party of two and could be conducted entirely from a mobile field laboratory.

The basic theme of this study is that determination of the economic value of water resources is a necessary condition for rational decision-making and management of these environmental assets, and their associated public goods, in developing countries. The research particularly evaluates the contingent valuation (CV) method as a technique for evaluating increments and decrements in environmental and natural resource service flows, and estimates households' evaluations for improvements in river water quality and connections to piped water supply for domestic uses. The study objectives were to (a) estimate the economic value of piped water supply and improved water quality in the Nzoia River Basin, Kenya, (b) evaluate the feasibility of using the CV technique to value an environmental amenity and its related quasi-public service in rural settings where respondents have limited education and monetary resources, (c) examine the role of temporal dimensions of bid payments (i e, frequency of payments) in contingent values for environmental commodities, (d) empirically investigate embedding effect bias in contingent valuation of improvements in river water quality improvement in a less developed economy, and (e) evaluate the role of water connection charges in households' willingness to hook onto piped water supply in Webuye Division, Kenya. Empirical analysis and estimates of the non-market value which local people assign to water quality in the Nzoia River and a private household water connection is based on a detailed survey of a representative sample of 311 households in Webuye Division of Bungoma District, Kenya. In an on-site survey carried out in May through September 1995, contingent markets were developed for the two goods, (1) improved river water quality, and, (2) provision of a private connection to water supply. The corresponding willingness to pay (WTP) values are explained using Ordinary Least Square regression models. Whatever the good, the WTP is seen to increase with income. However, the effects of other factors are more specific to the contingent good. In order of strength, the other determinants of WTP "quality" are sex, age, household ranking of status of domestic water source, distance from river to household residence, the other factors affecting WTP "connections" are existing source of water supply, household size, ranking of river water quality, and age of household head. On the whole, residents accepted the exercise of contingent valuation and were willing to pay important amounts (Ksh 459 and Ksh 386 on average per household per year, respectively, for goods 1 and 2). Discussion issues include policy significance of the resulting WTPs in terms of the demand for river pollution control and individual household water connections, the effect of the goods upon the CV evaluation process, the "Third World" impacts of frequency of payments in contingent valuation, including perceived-frequency and income-smoothing routes, the embedding effect in WTP values for water pollution abatement in the Nzoia River basin, the importance of pricing influences, specially payment profiles for initial connection charges, on household decisions to connect to piped water systems, and limitations of the study.

Escherichia coli (E. coli) is a widespread species that includes a broad variety of strains, ranging from highly pathogenic strains causing worldwide outbreaks of severe disease to virulent isolates which are part of the normal intestinal flora or which are well characterized and safe laboratory strains. The pathogenicity of a given E. coli strain is mainly determined by specific virulence factors which include adhesins, invasins, toxins and capsule. The aim of this study was to evaluate the prevalence and antibiogram profiles of E. coli pathotypes previously isolated from Kat River and Fort Beaufort abstraction water. A total of 171 E. coli isolates showed at least one pathogenic determinant among the isolated 278 E. coli. The other 107 isolates were negative for the tested virulence genes. All 278 presumptive isolates tested positive for the UidA gene, and were therefore classified as non-categorized pathogenic E. coli. The 171 pathogenic isolates had at least one characteristic gene of pathogenic E. coli and were identified and classified as enteropathogenic E. coli (6%), enterotoxigenicE. coli (131), uropathogenic E. coli (6), neonatal meningitis E. coli (14), diffusely adherent E. coli (1) and enterohaemrrhagic E. coli (1). Interestingly, no virulence genes were detected for the enteroinvasive E. coli and the enteroaggregative E. coli. The antibiotic resistance profiles for all isolates that were identified as E. coli showed 100% resistance to penicillin G, 98% resistance to ampicillin, 38% resistance to trimethoprim-sulphamethoxazole and 8% resistance to streptomycin. Multiple antibacterial resistance (MAR) was also observed, where 44% of the isolates were resistant to three antibiotics and 8% resistant to four antibiotics. The results of this study showed the Kat River and Fort Beaufort abstraction water are reservoirs of pathogenic strains of E. coli which harbour antibiotic resistance determinants that can cause serious health risks to the people in the surrounding communities.

The ultimate objective of this work was to develop a real-time method for detecting and monitoring β-D-galactosidase as a suitable indicator of the potential presence of total coliform bacteria in water environments. Preliminary comparison of the chromogenic substrate, chlorophenol red β-D-galactopyranoside and the fluorogenic substrate, MuGAL, revealed unreliable results with the fluorogenic technique due to interference from compounds commonly found in environmental water samples. Thus, the chromogenic assay was further explored. Hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside by β-D-galactosidase to yield chlorophenol red was the basis of this assay. Fundamental studies with chlorophenol red β-Dgalactopyranoside showed that β-D-galactosidase occurs extracellularly and in low concentrations in the polluted water environment. A direct correlation between enzyme activity and an increase in environmental water sample volume, as well as enzyme activity with total coliform colony forming unit counts were observed. Spectrophotometric detection was achieved within a maximum period of 24 h with a limit of detection level of 1 colony forming unit 100 ml[superscript -1]. This enzyme also exhibited physical and kinetic properties different from those of the pure commercially available β-D-galactosidase. Cell permeabilisation was not required for releasing enzymes into the extracellular environment. PEG 20 000 offered the best option for concentrating β-D-galactosidase. The source of β-D-galactosidase in the polluted environmental water samples was confirmed as Escherichia coli through SDS-PAGE, tryptic mapping and MALDI-TOF, thus justifying the further use of this method for detecting and/or monitoring total coliforms. Several compounds and metal ions commonly found in environmental water samples (as well as those used in water treatment processes) did have an effect on β-D-galactosidase. All the divalent cations except Mg [superscript 2+], at the concentrations studied, inhibited the relative activity of β-D-galactosidase in both commercial β-D-galactosidase and environmental samples. Immobilisation of chlorophenol red β-D-galactopyranoside onto a solid support material for the development of a strip bioprobe was unsuccessful, even though the nylon support material yielded some positive results. A monthly (seasonal) variation in β-Dgalactosidase activity from the environmental water samples was observed, with the highest activity coinciding with the highest monthly temperatures. Electro-oxidative detection and/or monitoring of chlorophenol red was possible. Chlorophenol red detection was linear over a wide range of concentrations (0.001-0.01 μg ml[superscript -1]). Interference by chlorophenol red β-D-galactopyranoside in the reduction window affected analysis. A range of phthalocyanine metal complexes were studied in an attempt to reduce fouling and/or increase the sensitivity of the biosensor. The selected phthalocyanine metal complexes were generally sensitive to changes in pH with a reduction in sensitivity from acidic pH to alkaline pH. The tetrasulphonated phthalocyanine metal complex of copper was, however, more stable with a minimum change of sensitivity. The phthalocyanine metal complexes were generally stable to changes in temperature. While only two consecutive scans were possible with the unmodified glassy carbon electrode, 77 consecutive scans were performed successfully with the CuPc-modified glassy carbon electrode. Among the phthalocyanine metal complexes studied, the CuPc-modified glassy carbon electrode therefore provided excellent results for the development of a biosensor. The CuPc modified-glassy carbon electrode detected 1 colony forming unit 100 ml[superscript -1] in 15 minutes, while the plain unmodified glassy carbon electrode required 6 hours to detect the equivalent number of colony forming units. CoPc, ZnPc and CuTSPc required 2, 2.25 and 1.75 h, respectively, to detect the same numbers of colony forming units. The CuPcmodified glassy carbon electrode detected 40 colony forming units 100 ml[superscript -1] instantly. In general, a direct correlation between colony forming units and current generated in the sensor was observed (R2=0.92). A higher correlation coefficient of 0.99 for 0-30 coliform colony forming units 100 ml[superscript -1] was determined. Current was detected in some water samples which did not show any colony forming units on the media, probably due to the phenomenon of viable but non-culturable bacteria, which is the major disadvantage encountered in the use of media for detecting indicator microorganisms. This novel biosensor therefore presents a very robust and sensitive technique for the detection and/or monitoring of coliform bacterial activity in water.

M.Sc. / Metal ions have become an increasing source of pollution in the natural waters of South Africa. This phenomenon is related to the rapid industrial, mining and agricultural activity growth along rivers, especially in the Upper catchment of the Olifants River, Mpumalanga. In general, metal ions have - negative effects on the physiology of fish and other aquatic biota in metal polluted waters. In this study. the sublethal effects of, manganese were determined by exposing the freshwater fish, Oreochromis mossambicus, to this metal in an experimental flow-through system. The exposure times were divided in acute (96 hours) and chronic (26 days) exposures, both at 23 ± 1°C. The results obtained showed changes in the general, haematological, metabolic, osmoregulatory variables, as well as the differential white blood cell counts. These changes indicated several effects in the physiology of a mossainblais after sublethal manganese exposure. Significant differences (P < 0.05) were found between the haematological variables of the control and exposed fish. During chronic exposure, an oxygen deficiency developed due to , the epithelial lifting of gill lamellae. As a result of hypoxia the red blood cell numbers, haemoglobin-, haematocrit and lactate concentrations increased to uplift the depleted oxygen situation. The significant differences (P < 0.05) found in the sodium, potassium,. calcium and chloride concentrations are mainly as a result of gill damage. Manganese showed a disruptive influence on the structural organization of the gill. The differential white blood cell counts performed , showed significant fluctuations. This leucocytosis and leucopenia are normal reactions of the fishes’ body against infections of foreign substances, such as metal ions. It was concluded that the general haematology, metabolism, osmoregulation and differential white blood cell counts can, be used as indicators in detecting the effects of sublethal manganese exposure on fish.

M.Sc. (Zoology) / Viticulture is an important agricultural practice in many countries. The long term use of pesticides in vineyards has resulted in increased concentrations of such pollutants in sediments, water and other environmental compartments. Mitigation measures in agriculture, especially vineyard agriculture, are a prerequisite to the sustained integrity of the natural environment, and specifically the aquatic environment. Mitigation presents itself in the form of water bodies, riparian buffer strips, ground vegetation cover, grassed field paths, natural or artificial wetlands and modification of pesticide application rate. However, to our knowledge no studies exist which highlight the state of dams related to viticulture or the use of mitigation measures, in South Africa. The study aimed to quantify the cumulative risk posed to dams on wine farms and the effect of pesticides (fungicides, herbicides and insecticides) on aquatic ecosystems while evaluating the use of mitigation measures in South African viticulture. Epilithic diatom community structure assessment and frustule abnormalities; zooplankton and macroinvertebrate community structure assessment, and characterization of mitigation measures were carried out at nine representative study sites on wine farms in the Western Cape, South Africa. Pesticide risk assessment models PRIMET and PERPEST were employed to assess the risk that pesticides pose at each site from available data. The Relative Risk Model was used to assess the risk posed to identified Risk Regions. Different risk categories were observed across the sites from PRIMET and PERPEST, ranging from no risk to high risk for specific pesticides and relative risk among the risk regions was assessed. Diatom community structure displayed spatial and temporal variability between sites as well as observable diatom frustule abnormalities due to pesticide input. Zooplankton and macroinvertebrate communities displayed variability spatially as well as temporally and this was linked to the presence of pesticides confirming the predictions from PRIMET, PERPEST and the RRM.

Cu is one of the most toxic elements that affect fish populations when the fish are exposed to concentrations exceeding their tolerance. To investigate the effects of elementary Cu on aspects of bioconcentration, histology and behaviour, O. mossambicus were exposed to 0 and 0.75 ± 0.20 mg/l of Cu for 96 hours (short-term study), and 0, 0.11 ± 0.02, 0.29 ± 0.02, and 0.47 ± 0.04 mg/l of Cu for 64 days (longterm study) under controlled conditions in the laboratory. For the long-term study fish were sampled for gills, liver, and kidney Cu accumulation analysis after 1, 32 and 64 days of exposure and after 1, 2, 4, 16, 32, and 64 days for gills, liver and spleen histology analysis. Cu accumulation was concentration-duration dependent with the highest accumulation capacity in the liver. A multifactor linear model was developed for the relationship between exposure dose, exposure duration and Cu accumulation in the organs with the liver model: Log L = 3.35 + 0.85W + 0.31T (r² = 0.892) giving a better fit than the gills: G = −35.09 + 10.58W + 17.58T (r² = 0.632). Where L = Cu accumulation values in the liver, G = Cu accumulation values in the gills (both in μg/g dry mass); W = exposure dose in water (mg/l); and T = exposure time (days). Using this model Cu accumulation in organs can be estimated when exposure concentration and duration is known. This model should be tested under different conditions to determine the potential of the model in monitoring Cu toxicity in the environment. Lesions were observed in the liver, gills and spleen in all Cu treatments at all exposure concentration and exposure durations. However, the incidence and the degree of alteration was related to the concentration of Cu and duration of exposure. The sequential appearance of lesions in the order of, hepatic vacuolar degeneration, fatty degeneration and necrosis indicated a gradual increase in liver damage with larger duration of exposure time and increasing Cu concentration. The initial lesions in the gills were manifested as hypertrophy and hyperplasia of the gill epithelium causing increase in the thickness of the secondary lamellae, mucous cell hypertrophy and proliferation, mucous hypersecretion, proliferation of eosinophilic granule cells and hyperplasia of interlamellar cells. With increase in exposure time, necrosis of the eosinophilic granule cells, lamellar oedema, epithelial desquamation and increase in severity of lamellar hyperplasia were observed. These lesions indicated an initial defence mechanism of the fish against Cu toxicity followed by advanced histological changes that were related to Cu concentration and duration of exposure. Changes in the spleen were haemosiderosis, increase in the white pulp and macrophage centres, reduction in the red pulp, and necrosis suggesting that fish exposed to environmentally relevant levels of Cu may be histopathologically altered leading to anaemia and immunosuppression. Regression analysis was used to quantify the relationship between the total activity of the fish, and duration of exposure. There was a gradual decline in fish activity related to Cu concentration and duration of exposure before introducing food into the tanks. There was a constant activity after introducing food in the tanks at the control and 0.11 ± 0.02 mg/l Cu exposure levels irrespective of exposure time. Analysis of covariance (ANCOVA) was used to test for the difference in slopes between treatments. There was no significant difference (p > 0.05) between slopes of the control and 0.11 ± 0.02 mg/l Cu, and between 0.29 ± 0.02 and 47 ± 0.04 mg/l Cu before and after introducing food in the tanks. The slopes of both the control and 0.11 ± 0.02 mg/l Cu were significantly different from those of 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu (p < 0.05). There were significant differences in the mean opercular movements per minute between treatments (p < 0.05). There was hyperventilation at 0.11 ± 0.02 mg/l Cu i.e. 87 ± 18 opercular movements per minute (mean ± standard deviation) and hypoventilation at 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu i.e. 37 ± 34 and 13 ± 6 opercular movements per minute compared to the control. Hypo- and hyperventilation were related to the lesser and greater gill damage, respectively. In conclusion Cu accumulation and effects on histology of the liver, gills and were related to the concentration of Cu in the water and duration of exposure showing a gradual increase in incidence and intensity with larger duration of exposure time and increasing Cu concentration. The fish were initially able to homeostatically regulate and detoxify Cu. However, as the exposure continued, the homeostatic mechanism appears to have failed to cope with the increasing metal burden causing advanced histological changes.

This study investigates and compares the environmental burdens of two different methods for producing potable water by using the environmental life cycle assessment (LCA). The first method, for the production of potable water, is used by Umgeni Water at their Wiggins Waterworks and it involves conventional processes. The second method is based on a South African membrane technology and currently it is used in three pilot plants around the country. The life cycle concept gives the means understand the environmental impacts associated with a product. process or activity by considering all life-cycle stages, from cradle- to-grave. Formal methodologies for conducting such studies have been developed and in this project the methodological framework endorsed by the International Organisation for Standardisation (ISO) 14040 series of standards has been used. By using this methodology and by tracing all processes involved in the production of potable water, it was found that the main contribution towards the environmental burdens of potable water is due to electricity generation. This conclusion is valid for both methods in vestigated. and as a result the recommendations focus on increasing the energy efficiency of waterworks in order to increase their overall environmental performance. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2001.

Yip, Ho-yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 181-201). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xvii / Abbreviations --- p.xix / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Polycyclic aromatic hydrocarbons (PAHs) --- p.1 / Chapter 1.1.1 --- Characteristics of PAHs --- p.1 / Chapter 1.1.2 --- Sources of PAHs --- p.2 / Chapter 1.1.3 --- Environmental fates of PAHs --- p.3 / Chapter 1.1.4 --- Effects of PAHs on living organisms --- p.5 / Chapter 1.1.4.1 --- General effects --- p.5 / Chapter 1.1.4.2 --- Effects on plants --- p.6 / Chapter 1.1.4.3 --- Effects on invertebrates --- p.7 / Chapter 1.1.4.4 --- Effects on fishes --- p.7 / Chapter 1.1.4.5 --- Effects on reptiles and amphibians --- p.8 / Chapter 1.1.4.6 --- Effects on birds --- p.9 / Chapter 1.1.4.7 --- Effects on mammals --- p.9 / Chapter 1.2 --- PAH contamination in Hong Kong --- p.10 / Chapter 1.3 --- Treatments of PAH contamination --- p.12 / Chapter 1.3.1 --- Physical treatments --- p.12 / Chapter 1.3.2 --- Chemical treatments --- p.13 / Chapter 1.3.3 --- Biological treatments --- p.14 / Chapter 1.4 --- Advanced oxidation processes (AOPs) --- p.16 / Chapter 1.5 --- Summary --- p.24 / Chapter 2. --- Objectives --- p.27 / Chapter 3. --- Materials and Methods --- p.28 / Chapter 3.1 --- Chemicals --- p.28 / Chapter 3.2 --- Photocatalytic reactor --- p.30 / Chapter 3.3 --- Determination of PAHs concentrations --- p.30 / Chapter 3.3.1 --- Extraction of PAHs --- p.30 / Chapter 3.3.2 --- Quantification of PAHs --- p.32 / Chapter 3.4 --- Optimization of physico-chemical conditions for PCO --- p.37 / Chapter 3.4.1 --- Determination of the reaction time for optimization of PCO --- p.37 / Chapter 3.4.2 --- Effect of titanium dioxide (Ti02) concentration and light intensity --- p.38 / Chapter 3.4.3 --- Effect of initial pH and hydrogen peroxide (H2O2) concentration --- p.38 / Chapter 3.4.4 --- Effect of initial PAHs concentration --- p.39 / Chapter 3.5 --- Toxicity analysis --- p.39 / Chapter 3.5.1 --- Microtox® test for acute toxicity --- p.39 / Chapter 3.5.2 --- Mutatox® test for genotoxicity --- p.42 / Chapter 3.6 --- Determination of total organic carbon (TOC) removal in optimized PCO --- p.43 / Chapter 3.7 --- Determination of degradation pathways --- p.43 / Chapter 3.7.1 --- Extraction of intermediates and/or degradation products --- p.45 / Chapter 3.7.2 --- Identification of intermediates and/or degradation products --- p.45 / Chapter 4. --- Results --- p.49 / Chapter 4.1 --- Determination of PAHs concentrations --- p.49 / Chapter 4.2 --- Optimization of extraction method --- p.49 / Chapter 4.3 --- Optimization of physico-chemical conditions for PCO --- p.49 / Chapter 4.3.1 --- Determination of the reaction time for optimization of PCO --- p.49 / Chapter 4.3.2 --- Effect of Ti02 concentration and light intensity --- p.60 / Chapter 4.3.3 --- Effect of initial pH --- p.88 / Chapter 4.3.4 --- Effect of initial H2O2 concentration --- p.99 / Chapter 4.3.5 --- Effect of initial PAHs concentration --- p.104 / Chapter 4.3.6 --- Improvements on removal efficiency (RE) after optimization --- p.113 / Chapter 4.4 --- Toxicity analysis --- p.122 / Chapter 4.4.1 --- Microtox® test for acute toxicity --- p.122 / Chapter 4.4.2 --- Mutatox® test for genotoxicity --- p.122 / Chapter 4.5 --- Determination of TOC removal in optimized PCO --- p.129 / Chapter 4.6 --- Determination of degradation pathways --- p.129 / Chapter 5. --- Discussion --- p.150 / Chapter 5.1 --- Determination of PAHs concentrations --- p.150 / Chapter 5.2 --- Optimization of extraction method --- p.150 / Chapter 5.3 --- Optimization of physico-chemical conditions for PCO --- p.151 / Chapter 5.3.1 --- Determination of the reaction time for optimization of PCO --- p.151 / Chapter 5.3.2 --- Effects of Ti02 concentration and light intensity --- p.152 / Chapter 5.3.3 --- Effects of initial pH --- p.160 / Chapter 5.3.4 --- Effects of initial H202 concentration --- p.163 / Chapter 5.3.5 --- Effects of initial PAHs concentration --- p.165 / Chapter 5.3.6 --- Improvements on RE after optimization --- p.167 / Chapter 5.4 --- Toxicity analysis --- p.169 / Chapter 5.4.1 --- Microtox® test for acute toxicity --- p.169 / Chapter 5.4.2 --- Mutatox® test for genotoxicity --- p.170 / Chapter 5.5 --- Determination of TOC removal in optimized PCO --- p.171 / Chapter 5.6 --- Determination of detoxification pathways --- p.172 / Chapter 6. --- Conclusion --- p.177 / Chapter 7. --- References --- p.181 / Chapter 8. --- Appendix I --- p.202

The upper part of the Revue basin in the Manica District, Mozambique is located in a mountainous area underlain by rocks of the Manica greenstone belt. This greenstone belt has alluvial gold deposits in the Revue river and its tributaries Chua and Zambuzi. Alluvial gold in the Manica District has been mined by local people using artisanal mining methods (panning) and by small scale companies. The recovery process of gold involves washing of the auriferous gravel with large quantities of water and the surface water quality has been impaired in this process. The aim of this dissertation is to assess the impact of alluvial gold mining on surface water quality in the Revue basin. Physical and chemical characteristics of the surface water were determined upstream of, within and downstream of the mining area and in the main tributaries immediately before flowing into the Revue river. Upstream of the mining area the water is clear and the rock types of the Manica greenstone belt are likely to be the only source of metals dissolved in the water. Metal concentrations are generally low except Cd, Mo and Ni but the water in this area meets all World Health Organization (WHO) recommendations for drinking water. In contrast within the mining area there are signs of pollution. The water is cloudy and the highest concentrations of most metals are found in the lower part of this area where mining activity is very intense. Thus, the alluvial gold mining is responsible for elevated metal concentrations and constitutes the major point source of pollution in the Revue basin. Water quality within the mining area has been affected and metals Ba, Pb and Mn have concentrations exceeding the WHO recommended values for drinking water. Downstream of the mining area the impounded water in the Chicamba Dam, which is the source of potable water for Chimoio City, reduces the water flow in the Revue river and sedimentation of suspended sediments occurs, together with associated adsorption and precipitation processes. This result in general improvement of water quality with only Ba and Pb concentrations remaining above the WHO recommended values for drinking water. Increase in concentration of metals AI, Ba, K, Pb and Sr occurring in the Chicamba Dam is likely to be due to input to the dam of water from rivers which cross the Granite-gneiss Complex. Geochemical speciation modelling using MINTEQA2 program suggests that the behaviour of metals Cr, AI, Mn and Fe is controlled by redox and precipitation reactions while the behaviour of As, Cd, Zn, Cu, Ni, Pb, Ba and Ca is controlled by adsorption on the sediment surfaces. Changes in environmental conditions, such as pH and dissolved organic matter (DOM) could result in metals being released back into the water. Modelling the effect of a change in pH and variation in DOM indicate that adsorption and precipitation would decrease with decreasing pH values and with increasing DOM. The chemical form of dissolved metals, the type of interactive processes (absorption and precipitation) and concentration of particulate matter gives the distribution of pollutants while the transport process affect the fate of pollutants in the Revue river water. / Thesis (M.Sc.)-University of Natal, Durban, 2000.