Made available in DSpace on 2014-10-09T12:54:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:58Z (GMT). No. of bitstreams: 0 / A qualidade das águas superficiais é de grande importância em qualquer localidade, é condição indispensável para o desenvolvimento, sob o aspecto socioeconômico ou ainda para a manutenção da qualidade de vida. Com o objetivo central de desenvolver um processo de biomonitoramento, a partir do emprego de um instrumento de diagnóstico, este trabalho apresenta um diagnóstico da qualidade física, química e biológica da água do Córrego Pirajuçara, localizado na Região Metropolitana de São Paulo. O córrego apresenta elevados níveis de degradação resultantes do processo de descarte direto de esgotos domésticos e efluentes. Para o monitoramento da qualidade da água foi desenvolvido um amostrador cerâmico a partir de um material adsorvente, capaz de adsorver os compostos tóxicos e poluentes com maior disponibilidade, presentes em solução na coluna de água, além de atuar como substrato artificial para o estabelecimento da biocenose de diatomáceas. As análises físicas e químicas da qualidade da água apresentaram altos teores de contaminação por compostos característicos de esgotos domésticos e processo de lixiviação de solos expostos. Como esperado, foi possível constatar o elevado grau de enriquecimento por nutrientes nitrogênio e fósforo, caracterizando o avançado estágio de eutrofização. A fração biológica estudada foi a biocenose de algas diatomáceas - Ochrophyta, que foi representada por 67 táxons, em nível específico, divididos em 27 gêneros e 20 famílias. O gênero de maior representatividade em relação ao número de táxons foi: Nitzschia com 9 táxons, seguido dos gêneros Eunotia com 8 táxons e Navicula com 6 táxons. Os gêneros Nitzschia e Navicula são citados em literatura mundial como gêneros de grande representatividade, indicadores de águas ricas em nutrientes e com baixas concentrações de oxigênio dissolvido. Foi possível constatar no período de estiagem 49 táxons, sendo 39 exclusivos. A predominância de espécies identificadas no período estiagem é devida a menor velocidade e variação do fluxo de água neste período, que garante a fixação mais estável das algas no substrato. O índice de biológico de qualidade (IBQA) da água calculado para o córrego no período de monitoramento apresentou valores característicos de águas poluídas. Os níveis de poluição constatados foram confirmados por meio da identificação de espécies com altos percentuais de abundância relativa e tolerância alta ou muito alta a eutrofização e à poluição orgânica, caracterizando águas muito fortemente poluídas a fortemente poluídas. A partir da análise dos resultados obtidos neste estudo concluiu-se que o diatomito possui propriedades favoráveis a sua utilização em monitoramento de qualidade de água de córregos urbanos apresentando informação sobre os compostos tóxicos dissolvidos presentes na coluna de água e permitindo o desenvolvimento de comunidades de algas que confirmam os elevados níveis de poluição. Desta forma a água do Córrego Pirajuçara foi caracterizada por elevados teores de compostos característicos de esgotos domésticos e a presença de espécies com alta tolerância a degradação da qualidade da água. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

There are many types of chemicals/contaminants present in the environment, ranging from synthetic chemicals to trace metals that are required for life. When an organism is exposed to a toxicant, adverse effects are generally first at the sub-organismal level. There is thus a need for physiological and biochemical indicators of organismal health and sub-lethal toxicant effects. A bio-indicator, or biomarker, is a response of a living organism to environmental changes or because of exposure to contaminants. The main objectives of this study were to evaluate and investigate the possible use of biomarkers as indicators of sub-lethal (chronic) effects induced by certain chemicals/pollutants on the Mozambique tilapia, Oreochromis mossambicus. The biomarkers were evaluated as a possible sensitive and reliable measure of effects due to exposure to pollutants. This study was divided into laboratory experiments and field evaluations. The laboratory experiments consisted of the evaluation of biomarkers in exposure studies on 18-24 day old O. mossambicus juvenile fish, to determine the sub-lethal effects induced by chemicals. Acetylcholinestrase (AChE), Ethoxyresorufin-O-deethylase (EROD) and glucose levels acted as the battery of biomarkers evaluated. Thirty (30) juvenile fish were exposed for 24 and 96-hours to sub-lethal concentrations of cadmium, zinc, pentachlorophenol (PCP) and cyanide. For the field evaluation, mature Oreochromis mossambicus of both sexes, were caught during the summer and winter at the Rust de Winter Dam, Loskop Dam and Hartebeespoort Dam. Rust de Winter Dam acted as the reference site. The biomarkers evaluated during the field studies include: erythrocyte AChE, ƒx-Aminolevulinic acid dehydratase (ALAD) and plasma glucose levels, EROD and liver glycogen. The laboratory (exposure) test used during this study was not sensitive enough to obtain reliable, repeatable results. But standardised procedures were established for possible use in future studies. During the field studies, ALAD, EROD and plasma glucose showed significant results and differences between the reference and polluted sites. More accurate results could be obtained at impoundments with higher levels of pollution. Although, erythrocyte AChE and liver glycogen did not show significant results during this study, they might also show more accurate and reliable results at higher levels of pollution. In future, chemical water analysis should be carried out during field evaluation to determine what chemicals/toxicants are present in the aquatic environment. Biomarkers will show the level of effects of the toxicant on the organism, while chemical analysis will determine the specific pollutant present in the water. / Prof. J.H.J. Van Vuren

The biological integrity of aquatic ecosystems has become threatened by the effects of eutrophication, acidification as well as increased organic and inorganic chemical loads. It is necessary to identify the effects of xenobiotics before the onset of death in an exposed organism or deteriorating changes at population level. Biochemical and physiological indicators such as enzymes and stress proteins could be used as a valuable tool for detecting chemical exposure and evaluating their effects on aquatic organisms. The use of selected enzymes in different organs/tissue was evaluated as possible indicators of stress in fish, in their natural environment as well as under controlled laboratory conditions. During the field assessment of enzymes it was found that selected enzymes could be used as indicators of pollution between high flow and low flow seasons when pollution conditions are more concentrated. However, the various enzymes are non-specific indicators of stress and could therefore, be influenced by environmental changes, handling and struggling in the nets. Exposure to sub-lethal and lethal iron concentrations caused significant differences between the levels of enzymes in exposed and control Oreochromis mossambicus, indicating that the use of enzymes under controlled laboratory conditions, toxicity testing is more effective. The demand for sensitive and specific biological assays needed to be satisfied. Heat shock induction after sub-lethal iron exposure was investigated in the reproductive organs/gonads of O. mossambicus. After the refinement of the standard protocol for the assessment of Heat shock protein 70 (HSP 70) it was found that HSP 70 induction are more intense in male individuals than in female individuals. Higher protein concentrations were also found in female reproduction organs possibly due to the presence of vitellogenin. The use of HSP 70 as a diagnostic tool to monitor cell damage after sub-lethal iron exposure was less effective due to several factors including (1) the selection of the target organ, (2) the different stages of sexual development between individuals, (3) the selection of the exposure toxicant and (4) the presence of another stress protein in female gonads. Most researchers use the Atomic Absorption Spectrophotometry (AAS) method to determine the metal content in fish organs/tissues. During this research it was attempted to find a more time effective, rapid, less hazardous and more economic method to determine metal content in fish organs/tissues. After comparison between the AAS method and Scanning Electron Microscope Energy Dispersive X-ray (SEM-EDX) microanalyses the AAS method was found to be the most effective method to determine metal content in fish organs/tissues. SEM-EDX microanalyses techniques need more refined sample preparation, calibration and operation skills. / Prof. J.H.J Van Vuren

M.Sc. / The impact of air pollution by power stations on water quality, just like any other source of water pollution, is an issue of concern for all the water users since any degradation in water quality affects the water's suitability for use. The study area in which Majuba power station is located was chosen because it is in an area free of industrialisation, and is also part of the Vaal catchment. This catchment area is very important because of its water supply for Gauteng province and provides an ideal opportunity to monitor surface water pollution from atmospheric sources such as power stations. The purpose of this research is to investigate the chemical, physical and biological quality of surface water in the vicinity (within a 31 kilometre radius) of Majuba power station. The study will determine whether this power station is causing any salinity and acidity problems at the chosen sampling sites. Salinity and acidity are water quality problems associated with atmospheric pollution. The aim of the study is to determine whether proximity to Majuba power station has an effect on the surrounding surface water quality. The research was conducted by means of water quality sampling, analyses and assessment. Water quality samples were taken from six sites (Majuba 1 to Majuba 6) in the vicinity of Majuba power station over a period of three years (1997 to 1999). The approach was to take four samples in a year coinciding with the four seasons of the year. Due to logistical problems only two sampling trips were undertaken, during 1997. In 1998 and 1999 the full four sampling trips were undertaken however in some instances the river was dry or was flooded hence no samples could be taken at the affected sampling sites (although a trip to the sampling site was made). The biological analyses where done on site using the biomonitoring technique while chemical analyses were performed at the laboratory at Eskom. The biomonitoring assessment was done using the biomonitoring technique. The chemical results were assessed in terms of the suitability for use for the aquatic environment. This was done by using the water quality guidelines for the aquatic environment. The chemical results indicated that in terms of salinity and acidity the site closest to the power station, namely Majuba 1 had the worst water quality of the six sites. Majuba 1 also had the worst results in terms of biomonitoring. Majuba 2 indicated elevated salinity levels. The other four sites, namely Majuba 3 to 6, did not indicate either salinisation or acidification. However, the biomonitoring results at these sites indicated, with the exception of Majuba 4, some deterioration in water quality. Majuba 4 had the best water quality in terms of biomonitoring. Reasons for this could not be determined. At present it is still premature to say whether acidity in the water is a problem. This is a preliminary study and currently a more detailed multidisciplinary study that includes disciplines such as atmospheric deposition, groundwater chemistry, soil profiles and hydrology is being undertaken on the Upper Vaal catchment to comprehensively determine the impact of air pollution from power stations on the surface water quality. The proposal will be presented to the South African Water Research Commission. The ultimate aim of the multidisciplinary study is to inform decision makers in water quality management sector regarding the impact of air pollution on surface water quality, in order for them to put in place abatement technologies or strategies to mitigate surface water quality pollution.

M.Sc. / Please refer to full text to view abstract

M.Sc. (Zoology) / Please refer to full text to view abstract

M.Sc. / The Elands River (Incomati System, Mpumalanga) is a biologically diverse and ecologically important riverine system. In terms of the South African National Water Law, the river can be regarded as an aquatic resource, with social, ecological and economical benefits to the local population and the environment itself. The ecological status of the system has, however been questioned, whereby concerns relating to the water quality and the ecological health of the Elands River has been raised. Initially, the concerns focused on an accidental industrial spill of “black liquor” into the Elands River by the Paper Mill at Ngodwana. Subsequently the groundwater in the vicinity of the Ngodwana Mill has possibly been contaminated with chlorides. The contaminated subsurface water has been discharged into the river, and is suspected to be impacting, primarily in the form of increased salinity, the integrity of the Elands River. This study assessed the ecological integrity of a segment of the Elands River between Waterval- Boven and the confluence of the Elands River with the Crocodile River. In addition this study investigated the possibility that increased chloride-based salinity levels were the factors affecting the ecological integrity of the Elands River. The study is divided into three main components. The environmental component involves the assessment of the surface water quality and flow, physical profile, current aquatic habitat status and a biotic integrity assessment of the Elands River and the Crocodile River directly above and below the confluence with the Elands River. An ecotoxicological component incorporated a bioassay of selected chloride-based salts, using daphnids and selected fish species as test organisms. Finally an Ecological Risk Assessment was carried out to evaluate the likelihood that adverse effects were impacting on the Elands River, as a result of the activities of the Ngodwana Mill. The water quality was assessed by implementing the methodology for the determination of present ecological status: water quality, as part of the preliminary determination of the ecological reserve. Historical water quality data were obtained from the Department of Water Affairs and Forestry and from Sappi. During the study, current water quality parameters were obtained from Sappi and parameters were independently sampled. Analyses of the water quality indicated that the Elands River has been subjected to eutrophication and increased levels of chloride-based salinity. Habitat integrity was analysed by constructing two dimensional site transects of the riparian zone and instream channel. Additional habitat indices, the Integrated Habitat Assessment System, the Habitat Cover Ratings and the Site Habitat Integrity system were applied. Habitat results indicate that the in stream habitats of the Elands River are abundant and linked to the flow regime. Additionally the assessments indicated that the habitat makeup of the Elands and Crocodile rivers is primarily riffle, run and rapids habitats, which facilitate the requirements of numerous invertebrate and vertebrate aquatic communities. Biotic assessments studied the integrity of the vegetation, invertebrates and ichthyofaunal communities. The integrity of the vegetation community was assessed by implementing the Riparian Vegetation Index. Results indicated that the riparian vegetation community was modified in varying degrees due to the encroachment of exotic and terrestrial vegetation elements and by anthropogenic activities. The integrity of the invertebrate communities were assessed by implementing the South African Scoring System. Results indicated that the integrity of the invertebrate community was exceptionally high in the vicinity of Hemlock. The invertebrate community structure changed however in areas were a water quality contamination was observed. The ichthyofaunal attributes were assessed by implementing the Fish Assemblages Integrity Index and the Sensitivity Weighted Index of Biotic Integrity. The ichthyofauna assessment revealed two aspects that have conservation importance. These aspects are the occurrence of an endangered species, Chiloglanis bifurcus, and a potentially geologically isolated subspecies of Labeo-barbus polylepis. The index results indicated that the ichthyofauna community structure followed similar trends to the invertebrates by responding to the mentioned stressors. Toxicological assessments were carried out using the standard Daphnid 48-hour LC50 and fish 96-hour LC50 tests. The species selected for the tests were the currently recognized test organisms (Daphnia pulex and Poecilia reticulata) in South Africa. Additional fish species were included in the tests, these species were Oreochromis mossambicus and Clarias gariepinus. Chloride-based salts were selected as the toxicants; these included calcium chloride, magnesium chloride, potassium chloride and sodium chloride. The tests were carried out under controlled conditions using standardised protocols. Results indicated that in excess, chloride-based salinity is toxic to invertebrate and vertebrate organisms. Additionally findings indicated that potassium chloride was the most toxic and sodium chloride the least toxic of the salts. Calcium chloride was selected as the most representative salt to represent salinity. The Ecological Risk Assessment was implemented after international and national frameworks were considered. The assessment was primarily based on the results obtained from the integrity assessment of the Elands and Crocodile rivers. Results obtained indicated that the localised biological template of the Elands River, in the vicinity of the Ngodwana Mill is moderately impacted by the activities of the Mill. The impact is primarily associated with the increased salinity content of the Elands River. Effects of the stressors were modified in relation to a dilution effect. Risks posed by the stressors are deemed to be restricted to a localised area, and it is highly improbable that the stressors would result in the loss of the biotic diversity and thus the ecosystem of the Elands River as a whole. Should the current situation prevail, the intensity and spatial extent or distribution of the stressor could increase. / Dr. V. Wepener

Magister Philosophiae - MPhil / The Lesotho Highlands Development Authority routinely uses the South African Scoring System version 4 (SASS4) in conjunction with water chemistry to monitor water quality of rivers in the Lesotho Highlands Water Project areas. The objective of this study was to test the efficiency of SASS4 in these areas. / South Africa

Elevated atmospheric concentrations of carbon dioxide (CO₂), partly driven by anthropogenic activity, are decreasing the pH of the oceans. This thesis aimed to assess the biological response of foraminifera to ocean acidification. Foraminifera are single-celled organisms that form the dominant component of many marine communities. A series of laboratory experiments were carried out on benthic intertidal foraminifera from the Eden and Ythan estuaries, NE Scotland, to assess the impacts of ocean acidification. The responses of two dominant intertidal species of foraminifera (Haynesina germanica and Elphidium williamsoni) to ocean acidification were initially investigated in a short-term (6 week) experiment. Multiple species and multiple stressors (seasonal temperature regime and elevated CO₂) were then incorporated in a long-term (18 month) mesocosm study to investigate the physiological consequences (e.g. survival, growth) of ocean acidification. Survival of both Haynesina germanica and Elphidium williamsoni was significantly reduced under low pH conditions. Live specimens of both these calcareous species were however recorded at low pH, in reduced numbers. Following long-term exposure to ocean acidification, foraminiferal populations were still dominated by calcareous forms. Agglutinated foraminifera were recorded throughout the long-term incubations but their numbers were not high enough in the initial sediment collections to allow them to contribute significantly to the populations. Overall, survival of all foraminifera was greatly reduced in elevated CO₂ treatments. Temperature effects were observed on foraminiferal survival and diversity with the largest CO₂ effects recorded under the seasonally varying temperature regime. Foraminiferal test damage for all live species was also highest under elevated CO₂ conditions. Test dissolution was particularly evident in Haynesina germanica with important morphological features, such as functional ornamentation, becoming reduced or completely absent under elevated CO₂ conditions. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism's survival and fitness. In addition, changes in the relative abundance and activities of these important species could affect biological interactions (e.g. food web function) and habitat quality.

The full text of this thesis/dissertation is not available online. Please <a href="mailto:upetd@up.ac.za">contact us</a> if you need access. Read the abstract in the section 00front of this document. / Dissertation (MSc (Microbiology))--University of Pretoria, 2006. / Microbiology and Plant Pathology / unrestricted