No description available.

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2018. / Soil ecosystems in urban, rural and agricultural environments receive chemical input from diverse sources of contamination, such as wastewater, industrial discharge, agricultural and urban runoff, fertilizers, vehicle leakages, landfill seepage, and animal waste overspill. Agricultural activities, transportation and industrial activities are suspected to be the highest sources of metal contamination in Cape Town. Although scientists generally have a good understanding of the toxicity of individual chemical pollutants, there is a great need to bridge the gap between our understanding of the toxic effects of exposure to individual contaminants and those effects from exposure to mixtures of chemicals. Woodlice and other soil detritivores have a particularly important ecosystem function in mineralising organic matter. Woodlice experience stress when exposed to toxic levels of metals in the diet, which can reduce feeding rates and may combine with natural stresses to reduce fitness and lower 'performance', thereby possibly resulting in these organisms being unable to completely fulfil their ecological function. The objectives of this study were: to compare how aluminium and manganese are bioaccumulated in Porcellio scaber in terms of the contribution of the hepatopancreas in metal storage compared to the rest of the body; and to determine whether mixtures of aluminium and manganese affect each other’s bioaccumulation and distribution in Porcellio scaber. Woodlice collected from a clean field site (Kirstenbosch Botanical Garden) were experimentally exposed in the laboratory to a range of environmentally relevant aluminium and manganese concentrations. The woodlice were exposed to these metals in single and mixed metal experiments. Oak leaves, collected from a clean site, were contaminated with aluminium and manganese. Therefore, the woodlice were exposed via their food source. A control experiment, where oak leaves were not contaminated, was also prepared. At week 0 and after five weeks of exposure, a sample of the woodlice (5 per exposure group) were dissected to remove the hepatopancreas. Hepatopancreas and rest of the body samples were acid digested and analysed for the metals by means of the ICP-MS. Contrary to the existing knowledge of metals accumulating in the hepatopancreas of woodlice when ingested, this study showed a higher bioaccumulation of aluminium in the rest of the body of woodlice after 5 weeks of exposure than in the hepatopancreas. This result was interpreted as a possible detoxification mechanism by woodlice through the use of the exoskeleton during the moult cycle. A similar result was found when woodlice were exposed to mixtures of aluminium and manganese. This translated to the fact that woodlice were unable to effectively deal with the toxicity caused by the mixture of aluminium and manganese. In the group of woodlice exposed to manganese alone, it was found that manganese concentrations in the rest of the body of woodlice exposed for 5 weeks were statistically higher than the manganese concentrations in the rest of the body of woodlice at the start of the exposure (week 0). However, in the hepatopancreas, there were no statistical differences between the manganese concentrations in week 0 woodlice and the manganese concentrations in week 5 woodlice. Furthermore, manganese concentrations in the rest of the body of week 5 woodlice were statistically higher than manganese concentrations in the hepatopancreas of week 5 woodlice. This was interpreted as further proof that woodlice would accumulate certain metals (aluminium and manganese in this case) in their exoskeleton so that elimination can follow during the moult cycle.

Ph.D. (Zoology) / The present study deals with the effects of metal-polluted aquatic habitats at five different localities on the Witwatersrand and the Orange Free State on the concentrations of lead, nickel, copper and cadmium in the organs and tissues of the Redknobbed Coot, Fulica cristata, the Sacred Ibis, Threskiornis aethiopicus, and the Reed Cormorant, Phalacrocorax africanus. The physical and chemical conditions of the water and the sediments which prevailed during the period of survey at the various sampling sites suggest that concentrations of parameters such as phosphates, nickel and lead in a number of cases exceeded the limits laid down by Kempster et at. (1980) for acceptable river water quality standards in South Africa. The major sources of pollution responsible for these conditions can primarily be related to sewage, mine and industrial effluents (urban) as well as agricultural practices (rural), respectively. Mining activities were largely responsible for the acidification and miniralization as well as metal pollution of the water and sediments, especially so at the Marievale Bird Sanctuary in the Blesbokspruit catchment area. However, automobiles are suspected to contribute much towards the lead concentrations in the water and sediments at all the sampling sites. Levels of cadmium were generally low and may be the only one of the four metals analysed which truly reflected unpolluted, environmental conditions for this metal in the water and sediments of all the sampling sites. The nutrient loads which suggest mild to moderate eutrophication of the water at all the localities can largely be attributed to sewage effiuents and surface runoff waters from the surrounding townships on the Witwatersrand as well as from inorganic fertilizers from farm lands in the vicinity of the Steynsrus and Senekal farm dams in the Orange Free State. These conditions resulted in the overall increase in primary and secondary production of the affected waters which also coincided with the development of submerged and floating water weeds such as Potamogeton pectinatus and Azolla filiculoides, respectively. The herbivorous Redknobbed Coot and to a lesser extent the piscivorous Reed Cormorant, benefitted directly or indirectly from these conditions. Data obtained during the investigation present a complex situation in terms of the environment and the biological availability of the four metals under discussion. A number of factors in both the abiotic and biotic components may have had an effect on fluctuations in metal concentrations. These may have acted individually and/or synergistically, making the interpretation of the data difficult. Cadmium occurred in the lowest concentrations of all four metals in all four the organs and tissues during all four seasons of investigation. In the case of the rest of the metals as well as the organs and tissues no specific, clear seasonal trend or sequence in the concentrations of the metals was discernible. Copper in the kidney and liver and lead in the bone and blood tissues had the highest mean concentrations over the four seasons of investigation. As far as the winter and summer seasonal tendencies are concerned, statistically significant differences occurred in the concentrations of some metals in specific organs and tissues between the winter and summer seasons, respectively. However, values recorded were not necessarily higher during a particular season. Lead (liver) and cadmium (kidney) concentrations were found to be significantly higher in winter 1991 whilst cadmium and copper (both in the blood) were significantly lower during this same season, compared to winter 1992. Concentrations of nickel did not differ significantly between organs and tissues such as the liver and blood for particular seasons. It was only nickel in the kidney and cadmium in the bone tissue which reflected definite seasonal trends for the four successive seasons of investigation.

M.Sc. / The recognition of the occurrence, importance and effects of contaminants on food chains and ecosystems has led to the development of biomonitoring programmes that use indicator species to estimate the levels in other parts of the ecosystem. There has been an increased awareness of potential pollution of ecosystems in Gauteng, South Africa, because of increased formal and informal urbanization, industrialization and mining activities. It is essential to obtain clear indications of metal pollution cause-effect relationships at ecosystem level in order to carry out effective management of these ecosystems. The objective was to investigate the application of an ecotoxicologically-based investigation of metals in selected bird species as bioindicators of metal pollution of ecosystems in Gauteng. Three passerine species were used, the Southern Masked Weaver (Ploceus velatus), the Red Bishop (Euplectes orix) and the Red-billed Quelea (Quelea quelea). The sites were selected to represent a theoretical pollution gradient from severely contaminated wetlands in the Vaal Triangle, to moderately contaminated wetlands in the Witwatersrand and Pretoria. A nature reserve in North West Province was chosen as reference site. The sites were Rietvlei in Tshwane, Roodekrans and Olifantsvlei in Johannesburg, Holfontein in the Vaal Triangle and Barberspan in North West Province. Two sampling surveys were carried out, one in 2002 and one in 2005. Feathers were collected for metal analyses. Blood samples were collected for biomarker (oxidative stress and DNA damage) and haematological analyses. The samples were digested using the microwave destruction technique. The metal analyses were carried out using ICP-MS. Oxidative stress enzymes (reduced glutathione content and catalase activity) were analysed in plasma samples and DNA damage was evaluated in red blood cells using the average base-pair length comparisontechnique. Haematological studies were done on the blood samples. The results were compared between the sites and surveys. The levels of stress correlated well with the levels of metals in the feathers. Sites with higher metal levels had higher levels of organism stress. Thus the study showed that the feathers can indeed be used in biomonitoring. Internationally there is a trend to incorporate Ecological Quality Objectives (EcoQOs) into legislation, especially when dealing with metal contamination. Within the framework of EcoQOs developed for birds the monitoring of contaminants forms a specific category of EcoQOs. However, due to a lack of available data, Reference and Target Levels still need to be set. The development of EcoQOs is especially important at this stage in South Africa. The recently promulgated National Biodiversity Act (10 of 2004) specifically provides for the preparation of conservation plans for identified ecosystems that are important because of their goods and services that they provide. Since there is no management tool available at present to develop a suitable management plan, the setting of EcoQOs that are in line with international standards and practices will be of immeasurable value to implementing the Act. Feathers from museum specimens were used to determine the Reference Levels for the various metals in the feathers. The Target Levels were calculated from the Reference Levels. These were compared to the Current Levels and the EcoQOs were determined for the metal levels in the feathers in weaver in Gauteng, South Africa. / Prof. V. Wepener

The use of intestinal parasites as indicators of pollution has increased in Europe due to the fact that parasites accumulate more of the available metals than their hosts. Eighty Largemouth yellowfish, Labeobarbus kimberleyensis (Gilchrist and Thompson, 1913) were collected between April 2005 and February 2006 with gill nets at RAU Island (26° 52, 249’ S, 28 10, 249’ E) in the Vaal Dam. The fish were killed, weighed and their lengths determined. Muscle, liver and spinal cord tissues were collected from each fish and the intestines removed and opened to expose Bothriocephalus acheilognathi. The position of attachment of B. acheilognathi in the host’s intestine was recorded. Thereafter tapeworms were collected in glass bottles and frozen. Water and sediment samples were collected. Clossed vessel microwave digestion was used to digest liver, muscle and tapeworms with Suprapur Nitric acid, and spinal cord tissue with Suprapur Nitric acid and Suprapur Hydrochloric acid. Thereafter metal concentrations of twenty three elements (Lithium, Beryllium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Arsenic, Selenium, Molybdenum, Cadmium, Tin, Antimony, Tellurium, Barium, Mercury, Thallium, Lead and Uranium) were determined specifically for each tissue type with an ICP-MS. Certified dogfish liver (Dolt-3) was used as a quality control standard. Water quality data was provided by Rand Water and included. Statistical data were analyzed with ANOVA and post-hoc tests and parasite infection statistics were calculated. Seasonality and intensity of tapeworms were compared to the intestine and total lengths of the fish. All the tapeworms were identified as the Asian Tapeworm B. acheilognathi Yamaguti, 1934. Bothriocephalus acheilognathi attached between 10% and 20% from the anterior end of host intestine. A 100% prevalence of Asian tapeworm was recorded in all surveys and the highest mean intensity of 231.1 was recorded in autumn and the lowest mean intensity of 73.7 was recorded in summer. The fecundity of largemouth yellowfish was not influenced by the high infection rate of B. acheilognathi as young fish fry was collected during the summer survey and the fish condition was good. No correlation was observed between parasite intensity and total length of each fish. This indicates that intensity is not dependant on host size. Parasite numbers are higher and differ from a previous study. Water quality of Vaal Dam changed in summer, due to transferance of water from the Grootdraai Dam. Algal counts and secchi disk readings increased. This indicates that zooplanktonic intermediate hosts increased due to an increase in food availability and increased the chance of infection. Significant differences were recorded in one sample T-test comparisons, while ANOVA indicated that significant differences between tissue groups and seasons occurred. Bioaccumulation of metals occurred in tapeworms in Selenium, Mercury, and Lead during autumn, Copper, Zinc, Selenium, Cadmium, Antimony, Thallium and Mercury during winter, Lithium, Zinc, Selenium, Cadmium and Antimony during spring and Zinc during summer. The highest mean value was recorded in sediment, followed by water, tapeworms and then the host tissue. The general trend was sediment > water > tapeworms > liver > spinal cord > muscle. Die gebruik van intestinale parasiete as indikatore vir besoedeling het in Europa verhoog omdat die parasiete meer van die beskikbare metale as hul gashere akkumuleer. Tagtig Grootbekgeelvisse Labeobarbus kimberleyensis (Gilchrist en Thompson, 1913) was tussen April 2005 en Februarie 2006 met kieunette te RAU eiland (26° 52, 249’ S, 28 10, 249’ E) in die Vaaldam versamel. Die visse is doodgemaak, geweeg en hul lengtes bepaal. Spier, lewer en werwelkolomweefsel was versamel van elke vis en die intestinums verwyder en oopgemaak om Bothriocephalus acheilognathi bloot te lê. Die posisie van aanhegting van B. acheilognathi in die gasheer se intestinum is aangeteken. Daarna is die lintwurms in glasbottels versamel en gevries. Water en sediment was ook versamel. Geslote-flesmikrogolfvertering was gebruik om lewer, spier en lintwurms met Suprapur® Swaelsuur en werwelkolom met Suprapur® Swaelsuur en Suprapur® Soutsuur te verteer. Daarna is die metaalkonsentrasies van drie-en twintig elemente (Litium, Berillium, Titanium, Vanadium, Chroom, Mangaan, Yster, Kobalt, Nikkel, Kopper, Sink, Arseen, Selenium, Molibdenum, Cadmium, Tin, Antimoon, Tellurium, Barium, Kwik, Tallium, Lood and Uranium) spesifiek vir elke weefseltipe bepaal met ‘n IGP-MS. Gesertifiseerde haailewer (Dolt-3) was gebruik as ‘n standaard ter wille van kwaliteitskontrole. Waterkwaliteitsdata is deur Rand Water verskaf en word ingesluit. Statistiese data was geanaliseer met ANOVA en nagraadse toetse en parasiet infeksie statistieke was bereken. Seisonaliteit en intensiteit van die lintwurms was vergelyk met die totale lengtes van visse en intestinumlengte van die visse. Al die lintwurms was as Asiese lintwurms B. acheilognathi Yamaguti, 1934 geïdentifiseer. Bothriocephalus acheilognathi was tussen 10% en 20% vanaf die anteriorgedeelte van die gasheerintestinum geheg. ‘n 100% persentasiebesmetting was opgeteken in alle opnames met Asiese lintwurms en die hoogste gemiddelde besmettingsintensiteit van 231.1 was opgeteken in die herfs en laagste gemiddelde besmettingsintensiteit van 73.7 waargeneem in die somer. Die broeisukses van die Grootbekgeelvisse was nie beïnvloed deur die hoë infeksies met B. acheilognathi nie, soos blyk uit die feit dat jong vissies versamel is tydens die someropname en die viskondisie was ook goed. Daar was geen korrelasie waargeneem wanneer die parasietintensiteite en totale lengtes van die visse vergelyk is nie. Dit dui dat intensiteit nie afhanklik is van gasheergrootte nie. Die parasietgetalle is hoër en verskil van ‘n vorige studie. Die waterkwaliteit van die Vaaldam het verander gedurende somer a.g.v. die toevoer van water vanaf die Grootdraaidam. Die algtellings en die secchi-skyf lesings het dus verhoog. Dit dui dus aan dat die getal soöplanktoniese tussengashere verhoog het agv die verhoogde voedselbeskikbaarheid en ‘n hoër kans van infeksie vir visse. Betekenisvolle verskille was waargeneem wanneer enkel monster T-toets vergelykings gemaak is, terwyl ANOVA betekenisvolle verskille tussen groepe en seisoene gewys het. Bioakkumulasie van metale in lintwurms het in selenium, kwik en lood gedurende herfs, en in koper, sink, selenium, cadmium, antimoon, tallium en kwik in winter, en in litium, sink, selenium, cadmium en antimoon in lente en in sink gedurende somer voorgekom. Die hoogste gemiddelde waarde was waargeneem in sediment, gevolg deur water, lintwurms en gasheerweefsel. Die algehele akkumulasie verwantskap is sediment > water > lintwurms > lewer > werwelkolom > spier. / Prof. Annemarie Avenant-Oldewage

M.Sc. / The water quality in the Vaal River system has deteriorated due to increasing industrial, mining and agricultural activities in the Vaal Dam and Vaal River Barrage catchment areas. This study was undertaken to determine the water quality in the Vaal Dam, and three localities within the Vaal River Barrage reservoir (i.e. the Riviera Aquatic Club, Abrahamsrust Pleasure Resort and at the Barrage structure). The objectives of this study, was to determine the fish population species composition, evaluate the general health of the selected fish species and obtain site specific metal bioaccumulation data for each locality. Suggestions and proposals for future monitoring and management of these waterbodies were also made. Metereological information on the Vaal River Barrage area was supplied by Rand Water, as well as physical and chemical data of fixed localities, sampled fortnightly (January 1997 to September 1998). In addition, water samples were collected at the Vaal Dam and the three Vaal River Barrage localities mentioned above, during February, May, August and November 1997. These samples were analysed by the Chemistry Department of the Rand Afrikaans University in accordance with standard methods. The chemical and physical characteristics and metal concentrations (aluminium, cadmium, calcium, copper, iron, magnesium, manganese, nickel, strontium and zinc) of these separate sets of data were then compared with Rand Water's Raw Water Quality Criteria. The aluminium, ammonia, chromium, copper, dissolved organic carbon, fluoride, iron, lead, manganese, nitrate, sulphate, total hardness and turbidity variables did not comply with the recommended guideline values. No guideline levels for strontium are available, however. Sedimentation, turbidity, salination and eutrophication within the Vaal River system play an important role in the bioaccumulation of metals by benthic organisms. Metals that adsorb to sediment particles, through various processes, are generally more persistent and less mobile than those in the overlying water and pose a severe long-lasting threat to the aquatic environment. Generally, the highest metal concentrations (AI, Cd, Cu, Fe, Mn, Ni, Pb, Sr and Zn) in the sediment samples collected at the four localities and seasons, were found in the finer sediment classes (class D). The Riviera Aquatic Club locality had the highest overall concentrations of the metals analysed. The adult fish communities within the Vaal Dam and Vaal River Barrage were assessed, as it is believed that the fish community structure is indicative of environmental conditions. Adult Labeo capensis, Labeo umbratus, Cyprinus carpio, Clarias gariepinus, Barbus aeneus and Micropterus sa/moides, were collected (using gill nets) to determine the adult fish community composition and age. When compared with a study conducted by Mulder (1971), it is clear that Labeo capensis has remained the most abundant species within the system, but that Barbus aeneus has now been replaced by Labeo umbratus as the second most abundant species. Furthermore, age determination tables (Mulder, 1971) were used to classify the fish population between the ages of 2 and 7 years. This indicates a healthy, dynamic community structure where recruitment is taking place. The Health Assessment Index (HAl) was used to determine the general health of the two fish species selected for metal analysis (i.e. Labeo capensis and Labeo umbratus). Except for moderate to severe gill damage recorded, no damage to external variables, were of concern. However, both Labeo capensis and Labeo umbratus had high percentages (89% and 93%, respecii tively) of abnormal livers. Using the Plascon Colour Chart (Watson, personal communication), these livers were classified as ranging from tan to "coffee with cream" in colour. High haematocrit and plasma protein levels were observed and could be due to environmental stress, while the White Blood Cell Counts were within normal ranges. Generally speaking, only mild to moderate parasite infections were observed and probably do not pose a serious health threat to the fish host. Total HAl values for Labeo capensis indicate that this this fish population was in relatively good health, but too few Labeo umbratus individuals were collected to make accurate assumptions about this population. Metal analysis (AI, Cd, Cu, Fe, Mn, Ni, Pb, Sr and Zn) was carried out on the tissues and organs (skin, muscle, gill filaments, gill arches, liver, hindgut content, gonads and vertebrae) of Labeo capensis and Labeo umbratus, collected during the study period. Only aluminium, iron and strontium are discussed. Aluminium concentrations were relatively high at all of the localities, but as pH values were mostly alkaline, aluminium is rendered biologically unavailable and as for iron, was mostly accumulated in the non-edible portion and viscera of the fish. Strontium accumulates in bony tissues due to its similarity with calcium, but is not essential for bone formation. The human health risks of these metals in the edible portion of the fish still have to be refined and communicated to the general public of South Africa. In conclusion, this baseline study has determined the metal concentrations in the aquatic environment (due to anthropogenic activities) that may be accumulated by fish and may affect the adult fish community structures and their general health.

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2016. / Generally, aluminium (Al) is required as a micronutrient by plants. The metabolism of Al within the plant can exert a number of effects within the plant. These include: interfering with cell division in both root tips and lateral roots, increasing cell wall rigidity, maintaining the correct cellular redox state, as well as the various other physiological and growth responses. Al is one of the most abundant elements in the earth’s crust and becomes toxic in many plants when the concentration is greater than 2-3 ppm, where the soil has a pH<5.5. Iron (Fe) is an equally important element, and the toxicity of this metal possesses constraints primarily on wetland plants growing in acidic soils that have high reducible iron content. The impact of metal toxicity (Al and Fe) requires an understanding of many aspects related to Al and Fe uptake, transport and distribution by plants in wetland ecosystems. In this study, three species of Cyperus viz. Cyperus alternifolius, Cyperus prolifer and Cyperus textilis were used to carry out phytotoxicity tests to monitor xenobiotic substances.

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No description available.

Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Leptospirillum ferriphilum is a moderately thermophilic, iron-oxidizing bacterium that was isolated from a continuous-flow biooxidation plant used for the recovery of gold from arsenopyrite ore concentrates. Over many years of continuous selection, L. ferriphilum and other bacteria associated with this environment developed resistance to high concentrations of arsenic. We investigated the arsenic resistance genes (ars) of Leptospirillum ferriphilum strain Fairview and compared these genes to the ars genes from other Leptospirilli. An arsenic resistance operon (ars operon) was isolated from a L. ferriphilum Fairview genebank. We discovered that this ars operon was situated in between divergently transcribed transposase (tnpA) and resolvase (tnpR) genes related to the Tn21 subfamily of transposons. Sequence analysis of this transposon ars operon indicated the presence of arsRCDAB genes and an additional CBS orf, located in between the arsA and arsB genes. The 8.5 kb L. ferriphilum transposon ars operon (TnLfArs) was shown to be present only in L. ferriphilum strain Fairview and none of the other Leptospirillum strains. The TnLfArs conferred resistance to arsenate and arsenite in an Escherichia coli ars mutant. We also showed that the TnLfArs is capable of transposition in Escherichia coli. / AFRIKAANSE OPSOMMING: Leptospirillum ferriphilum, ‘n matig termofilies, yster-oksiderende bakterium, is een van `n konsortium bakterieë betrokke by die biologiese herwinning van goud uit arsenopiriet erts. Oor vele jare het die selektiewe druk, weens hoë arseen konsentrasies teenwoordig in die erts, veroorsaak dat L. ferriphilum en die ander bakteriee geassosieer met die omgewing, verhoogde vlakke van weerstandbiedendheid teen die metaal opgebou het. Die doel van die studie was om die aard van die aanpassing op die molukulere vlak vas te stel deur die gene wat in L. ferriphilum (Fairview ras) hiervoor verantwoordelik is te identifiseer en te vergelyk met die van ander Leptospirilli. `n Arseen weestandbiedendheids operon (ars operon) is met behulp van `n L. ferriphilum geen-bank geisoleer. DNA-volgorde bepaling het aangedui dat die operon arsRCDAB gene bevat, sowel as `n CBS orf, gelee tussen die arsA en arsB gene. Die hele operon is gelee tussen `n tnpR- (resolvase) en tnpA (transposase) gene wat in teenoorgestelde rigtings getranskribeer word. Hierdie gene behoort aan die Tn21 familie van transposons. Daar is gevind dat die 8.5 kb L. ferriphilum transposon wat die ars operon bevat (TnLfArs) slegs teenwoordig is in die Fairview ras van L. ferriphilum maar in geen van die ander Leptospirillum rasse nie. Die TnLfArs het weerstanbiedendheid verleen, teen beide arsenaat en arseniet, aan `n Escherichia coli arseen-sensitiewe mutant. Die vermoë van die transposon (TnLfArs) om transposisie te ondergaan is ook in E. coli bevestig.