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Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2011. / World wide urban rivers are the most utilised and degraded. A variety of everyday sources of metal pollution exist that is entrenched in the modern way of life. Lately there has been a tremendous growth in the establishment and development of human settlements, both formal and informal in the Cape Town area. The surroundings of the Kuils River are not excluded from this. There are various communities in close proximity to the Kuils River. Due to this, more industries are also being established. This has caused an increased production of potential environmental pollutants, including metals. The aim of the study was firstly, to identify potential sources of metal pollution along the entire length of the Kuils River, in order to identify sampling sites. Secondly, to identify the metals contaminating the water and sediment of the Kuils River. Thirdly, to determine the bioaccumulation of metals in freshwater snails (Physa ecuta). Four sampling sites were identified along the Kuils River. Freshwater snails (P. acuta), sediment and water were collected every 2 months for a period of one year. The following metals were investigated: Aluminium (AI), Cadmium (Cd) Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Manganese (Mn), Nickel (Ni.) and Zinc (Zn). Samples were digested with 55% nitric acid. The Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES) were used for metal analyses. The results were statistically analysed by means of ANOVA on ranks using the Sigmastat statistical package. Results revealed that most metals found in water, sediment and snails had significantly higher concentrations at site 1. This is possibly due to input from the surrounding urban area and nearly agricultural activities. Water concentrations of AI, Cu, Mn and Zn were higher than the DWAF (1996) guidelines. Sediment was mostly contaminated with AI, Fe, Pb and Zn, while the snails contained significant levels of Cu, Fe, Mn and Zn. Further investigations involving toxicity testing should be conducted to determine the toxicity of these metals to (Physa acuta).

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2007 / Urban rivers are the most utilised and yet degraded rivers worldwide. The urban rivers of the Western Cape are no different. The Lourens River flows through the agricultural and urban areas of Somerset West in the Western Cape and as a result is subjected to a variety of pollution sources. In the upper reaches this river flows through two large farms where metal containing pesticides are used. Further downstream it passes through an urban area where a variety of pollution sources could contribute to the contamination of the river. The extent to which the Lourens River, and the ecosystem it supports, is affected by metal pollutants is not known. The aim of this study was to determine the concentrations of metals in the Lourens River as well as the contribution of agricultural and urban activities to metal contamination of the river. Sediment and crab (Potamonautes perlatus) samples were collected over a period of one year from seven sites over the length of the river. Sediment samples were also collected from a sedimentation pond on the bank of the river where orchard run-off water is remediated. Preliminary analysis of samples was done for ten metals (AI, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb and Zn). Results from these analyses determined the selection of six metals (AI, Cr, Cu, Fe, Mn and Zn) for further investigation in this study. The concentrations of metals detected in collected samples varied significantly throughout the sampling period. This can be attributed to various factors such as rainfall patterns, the fact that pesticide application varies throughout the year and other urban activities. AI, Cr, Fe and Zn were found in significantly higher concentrations in the urban areas. These higher levels of contamination, relative to the upper parts of the river, can probably be attributed to various urban activities contributing to the contamination of run-off into the river. The sedimentation pond results revealed high concentrations of AI and Fe, while Cu, Cr, Mn, and Zn were found in lower concentrations. All six metals however followed the same pattern where the first four sampling occasions showed higher concentrations than the last three occasions. It can be concluded that agricultural and urban activities do contribute significantly to the metal contamination of the Lourens River.

Diss. (sammanfattning) Stockholm : Univ., 2004. / Härtill 5 uppsatser.

M.Sc. / The study looks into the sediment-bound metals (Fe, Mn, Cu, Cr, Cd, Co, Pb, Ni, Zn and Hg) of the Leeu/Taaibospruit catchment, which is impacted by agricultural, industrial and urban development. A number of chemical procedures, including total metal determination, the Tessier-sequential extraction scheme, the BCR Protocol, evaluation of the % TOC and determination of AVS to SEM ratios were applied to sediment samples collected from eight sites along the two rivers in the study area. Samples were collected during both high flow (summer) and low flow (winter) conditions. Following the chemical characterisation, bioaccumulation testing was conducted by exposing chironomid larvae to the sediment samples collected in from the study sites and determining their metal uptake relative to control specimens in uncontaminated sediments. These bioaccumulation results were then considered in conjunction with the chemical parameters in an attempt to identify any trends and correlations. Significant spatial and temporal differences were found in the metal concentrations from the study area. The total extraction results indicated that abundant amounts of Cr and Fe are present throughout the system. This was expected based on the make-up of the underlying geology. In addition, one of the sites, which is in close proximity to the town of Sasolburg, was identified as a potentially contaminated site. This site had significantly higher concentrations of Zn, Cu, Pb and, most notably, Hg when compared to the other sites. The elevated metal concentrations are most evident in samples collected under low flow conditions, but are also seen in the high flow Hg concentrations. Sequential extractions showed that Fe and Cr are concentrated in the residual phases of the sediment. Copper is largely present in the oxidisable fraction under low flow conditions, but also has considerable residual and reducible chemical forms. Manganese and Zn are distributed among all the different chemical phases and are therefore likely to be readily available for uptake by benthic organisms. The TOC was found to be highest during low flow conditions and at those sites with observable amounts of organic debris from the surrounding reeds and other vegetation. The AVS/SEM ratios were used to predict that due to the formation of insoluble metal sulphides, Cd, Cu, Hg, Ni, Pb and Zn are unlikely to be bioavailable at certain sites, i.e. the contaminated site 1 and at site 5, which only has agricultural impacts. In general, the bioaccumulation of Fe, Co, Ni, Cr and Mn was higher in the test larvae than the control larvae. Bioaccumulation of Cu, Pb, Zn and Hg levels were only higher than the control worms at sites where contamination was suspected to have taken place. Average bioaccumulation factors indicated that Hg is the metal that is most readily available for bioaccumulation, followed by Cu, Zn and Mn. All of these metals were bioconcentrated in the tissues of the test chironomids, while levels of Fe, Ni, Cr and Pb were found to be lower in the organisms than in the sediments. Although many of the chemical fractions were found to correlate significantly with the uptake of the different metals, the best overall correlation existed between the bioaccumulated metal and the total non-residual fraction. In fact, the sum of the first four steps of the Tessier-scheme correlated significantly with the bioaccumulated metal for all elements considered in the calculation, except for Pb. Additionally, the predictions made by the AVS model were found to be useful in justifying the behaviour and accumulation patterns of Hg, Zn and Cu at certain sites. The correlations and bioavailability clearly differed spatially, temporally and among the different elements. It is therefore suggested that prediction of the bioavailability and subsequent uptake of sediment-bound metals will require as many chemical and environmental factors as possible, and should include bioaccumulation and toxicity testing in order to examine the validity and completeness of these predictions.

M.Sc. (Aquatic Health) / Previous studies showed that the upper reaches of the Taaibosspruit catchment in the north eastern region of the Free State, contains elevated concentrations of mercury in the sediment. Additional laboratory-based bioaccumulation studies with sediment-dwelling Chironomidae larvae revealed that the mercury was in a bioavailable form, but it was uncertain to what extent this mercury was in the methylated organic form. Therefore, a study to assess the extent of inorganic- and methylmercury contamination in the water and sediment, as well as the uptake of this pollutant by aquatic and aquatic associated biota was undertaken. This study tested the hypothesis that bioaccumulation of mercury occurs in the different trophic levels of the upper reaches of the Taaibosspruit ecosystem. The objectives of this study were to determine the spatial and temporal physico-chemical characteristics of the water and sediment of the Taaibosspruit system; to determine the extent of mercury distribution within the water and sediment of the Taaibosspruit system; to determine the degree of bioaccumulation and possible biomagnification of mercury by the biota from the different trophic levels of the ecosystem in the Taaibosspruit system; to determine the distribution of cadmium, chromium, copper, lead, manganese and uranium within the water and sediment of this system, as well as the degree of bioaccumulation of these metals by invertebrates and fish; and to determine whether the aquatic macroinvertebrate community structures change along the mercury pollution gradient in the Taaibosspruit system. Sampling was done bi-annually at five sites during late high- and late low flow periods. The reference site is situated on a tributary of the Taaibosspruit, which is not directly influenced by discharges from the industrial complex. In situ water quality parameters were determined at each site and the following samples were collected: water, sediment, aquatic rnacroinvertebrates, vertebrates (fish and amphibian species), as well as noninvasive tissue from birds (feathers). The physico-chemical characteristics of the water were determined by measuring the chlorophyll-a concentrations, nutrient levels and suspended solid content. The sediment was analysed for organic content, water content, as well as sediment particle size distribution. The methylmercury concentrations in the water, sediment and biotic components were determined through cold vapour atomic fluorescence spectrometry, whilst inorganic mercury, cadmium, chromium, copper, lead, manganese and uranium concentrations in these samples were determined through inductively coupled plasma mass spectrometry. All analyses were subjected to appropriate quality analysis and quality control procedures. The relationship between environmental mercury exposure and biological effects was determined using changes in the macroinvertebrate community assemblage structure as the biological endpoint. The invertebrate samples were retained for enumeration and lower taxonomic identification in the laboratory. Data were subjected to the appropriate univariate statistical analysis (oneway ANOVA and regression), as well as multivariate statistical analyses (redundancy and principal component) to study spatial and temporal trends in mercury distribution and associated biological responses. This study showed that elevated concentrations of some nutrients and other dissolved solids were present in the system and that the water quality from the upper catchment of the Taaibosspruit (near the industries) had an impact on the downstream sites. The highest mercury concentrations were found at the sites closer to the industrial complex. These concentrations were higher than the concentrations from the reference site and when compared to international mercury guidelines, it was found to be too high. Comparison of the mercury concentrations in the water and sediment with environmental parameters also revealed that some of these parameters significantly influenced the environmental mercury concentrations. It was found that the biota has bioaccumulated mercury, which has resulted in the biomagnification of methylmercury by the biota from the different trophic levels of the ecosystem from this system. The results of the other six metals showed that the highest concentrations were found at the sites closer to the industries, with very high cadmium and copper concentrations in the water at the site where wastewater from the industries enters the system. These high concentrations in the water, suspended particles and sediment resulted in the accumulation of the metals by the biota present in this system. The sediment-dwelling Chironomidae-larvae bioaccumulated these metals to higher levels than the other biota from this system. The response of aquatic macroinvertebrates to high mercury exposure was dearly visible, as the sites where the environmental mercury concentrations were the highest, had low species richness. The environmental variables also influenced the community structure of the macroinvertebrates by reducing the number of different families at the more impacted sites. The results have shown that some of the fauna in the Taaibosspruit system were reduced in favour of the more tolerant families, namely Chironomidae and Oligochaeta. Thus, it was found that Taaibosspruit system is impacted upon by the surrounding industries, namely by enhancing the bioaccumulation of mercury, and influencing the macroinvertebrate community structure.

Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2012. / The Diep River is approximately 80 km in length and runs through agricultural land and urban parts of greater Cape Town, South Africa before entering the Atlantic Ocean, via an estuary. Generally, metal pollution in South African rivers is not well documented and using plants to monitor metal bioaccumulation is even less documented. The aim of this study was to investigate aluminium, iron, copper and zinc metal pollution in the Diep River and bioaccumulation of these metals in the leaves and stems of the submerged macrophyte Ceratophyllum demersum L. Furthermore, the effects of bioaccumulated metals on membrane integrity and chlorophyll content of these plants were investigated. Site 1 was situated in the upper reaches of the river adjacent to agricultural land, while site 2 was in an urban area, where industrial activities predominate. C. demersum (from an uncontaminated source) were introduced into the river at the two sites and compared with one another on a fortnightly basis over a 12 week period. Plants at site 2 were also compared to existing plants that were naturally growing at the site. Comparisons were also made between leaves and stems of the plants, to establish the organ of preference regarding metal accumulation and storage. Samples were digested with nitric acid and an ICP-MS was used to analyse metal concentrations in the water, sediment and plants. Chlorophyll extraction was done using dimethyl sulphoxide (DMSO) and the absorbance values determined using a spectrophotometer. Chlorophyll a, chlorophyll b and total chlorophyll contents were recorded and compared. Cell membrane integrity was determined by leaving plants for 24 hours in deionised water and measuring electrical conductivity and solutes (sodium, calcium, potassium and magnesium) before and after placement of the plants.

The biosorption of copper, nickel, gold and platinum from single metal aqueous solutions by the nickel hyperaccumulator Berkheya coddii plant biomass was investigated. Potentiometric titrations of the biomass and determination of optimal sorption pH for each metal showed that nickel ions were released from the biomass into solution. The presence of free nickel ions interfered with the uptake of the other three metals and further biosorption investigations were discontinued. Three fungal isolates found colonising metal solutions were cultured and screened for their ability to remove 50 mg.l⁻¹ of copper, nickel, gold and platinum from solution and to survive and grow in precious metal refinery wastewaters. One isolate was selected for further studies based on its superior metal uptake capabilities (35 and 39 mg.l⁻¹ of gold and platinum, respectively) and was identified as Phoma glomerata. Copper, nickel, gold and platinum uptake studies revealed that nickel and gold were the most toxic metal ions, however, toxicity was dependent on pH. At pH 6 more biomass growth was achieved than at lower pH values and metal uptake increased by 51 and 17 % for copper and nickel, respectively. In addition, the production of extracellular polymeric substances played a role in base metal interaction. Precious metals were observed to be preferentially removed from solution, complete removal of gold and platinum was observed at all initial pH values, 89 % of copper was bioaccumulated at an initial metal concentration of 55 mg.l⁻¹ (pH 6) and only 23 % of nickel was removed from solution under the same conditions. Metal bioaccumulation was confirmed through transmission electron microscopy and micro particle induced X-ray emission. The effect of P. glomerata immobilised in a packed bed reactor on precious metal refinery wastewaters was investigated. It was found that the fungal isolate was not able to remove the high salt and chemical oxygen demand concentrations found in the wastewaters, however due to its ability to survive and grow in undiluted wastewater and remove metal ions from solution it may be utilised as a metal detoxification step in the treatment process train. / PDFCreator Version 0.9.0 / AFPL Ghostscript 8.53