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A comprehensive literature review is presented concerning pesticides; in particular the organochlorine insecticides, DDT and dieldrin, and their role in the pollution of water resources. The results of a laboratory study on the removal of DDT and dieldrin (HEOD) by adsorption onto a clay of the montmorillonite type (bentonite) are presented. For an initial DDT concentration of 100 μgm/l, the addition of bentonite at concentrations of 1.0 gm/l and 10.0 gm/l results in the removal of about 60 and 72 per cent, respectively, of the insecticide. For an initial HEOD concentration of 100 μgm/1, the addition of bentonite at concentrations of 1.0 gm/l and 10.0 gm/l brings about the removal of about 15 and 30 per cent, respectively, of this insecticide. The results of a laboratory study on the desorption of DDT and HEOD from the bentonite are presented. Both insecticides are desorbed from the clay, the HEOD being desorbed to the greater extent and the DDT desorption being quite minimal. The results of a further laboratory study conducted to ascertain the ability of bentonite clay to remove, by adsorption, insecticides from solution while settling through a quiescent water body are presented. Bentonite at concentrations of 1.0, 5.0, and 10.0 gm/l removes about 44, 48, and 54 per cent, respectively, of DDT from the quiescent water body initially containing 100 μgm/1 DDT. Bentonite at concentrations of 1.0, 5.0 and 10.0 gm/l removes about 14, 23, and 30 per cent, respectively, of the HEOD from the quiescent water body initially containing 100 μgm/1 HEOD. The results of an inorganic blanketing study indicates that the addition of a layer of sand over DDT and HEOD contaminated benthic deposits will block, somewhat, the desorption of these insecticides into the overlying waters. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The rapid growth in world population and industrial technology over the past few decades has resulted in increasing competition for the use of the earth's resources. This has caused what have been termed "resource-use conflicts", the resolution of which requires a "decision-making process". In order to understand the manner in which resource-use decision-making operates in British Columbia, some legal, economic, social, administrative, and environmental factors involved were examined. As a working example of such decisionmaking, a detailed case history of the application for a Pollution Control Permit from the provincial Pollution Control Branch by Utah Construction and Mining Corporation is presented. The controversy surrounding the Company's plans to dispose of 9.3 million gallons of mine tailings daily into Rupert Inlet on northern Vancouver Island resulted in the holding of a public hearing by the Pollution Control Branch, the passage of new environmental legislation, and a court case. These events cast considerable light on the manner in which resource-use decision-making, that involves consideration of environmental factors, operates in British Columbia. Many weaknesses in the decision-making process are apparent, particularly the reluctance of the decision-makers to consider critical environmental factors in arriving at a conclusion regarding the use of resources. Two experimental studies were undertaken: firstly, a brief survey of a number of mining operations in southern British Columbia to determine whether or not the administration of pollution control in the province was effectively preventing unacceptable deterioration in the quality of water draining the mined areas; and secondly, a study of the circulation of water in Rupert Inlet, and the effect of the tailings discharge on the turbidity of the water in the inlet, to test the validity of the basic assumptions behind the granting of a pollution control permit to Utah Construction and Mining Corporation. The objective of these two studies was to show that with a limited budget and in a limited time it was possible to determine the adequacy of the existing pollution control decisionmaking process. The survey of the quality of water draining areas of mining activity revealed that existing mechanisms were not effectively preventing unacceptable heavy metal pollution of water, and that conventional tailings disposal is frequently inadequate and unacceptable from an environmental standpoint. The oceanographic survey of Rupert Inlet demonstrated the falacious nature of the basic assumption underlying Utah's pollution permit. Both studies showed conclusively that the pollution control decision-making process was not operating satisfactorily in British Columbia and that with limited time and finances it was possible to generate some of the information necessary to an adequate decision-making process. / Forestry, Faculty of / Graduate

Concentrations of 18 metals, including toxic metals (As, Cd, Cr, Ni and Pb) and essential metals (Al, Ba, Be, Co, Cu, Fe, Li, Mg, Mn, K, Sr, V and Zn) in various compartments (sediment, floc, and periphyton) were measured in the Florida Everglades to (i) establish the spatial distribution pattern of the metals in the Everglades and (ii) quantify the major sources of the 18 metals present in the Everglades. The highest mean concentrations of all metals analyzed in the Everglades were detected in soil, followed by floc and periphyton. Most metals exhibited random spatial distribution patterns. Risk assessment using Sediment Quality Guidelines (SQGs) concluded that all toxic metals (Cd, Cr, Pb, Ni, Cu, Zn and As) exhibited average concentrations that were well below FL guidelines as well as other domestic and international guidelines. On the basis of the current study, the Everglades can be considered a pristine environment.

A pollution survey was done in Milnerton industrial area along three transects, the coastal road, the R27 road, and the N7 road. In this project lichens were used as pollution monitors and their availability, abundance and percentage cover were used to estimate the level of pollution. Lichen specimens were collected from St. James, which is far from the pollution source and put in the vicinity of the Caltex oil refinery for four month after which they were analysed for their fluorescence and chlorophyll content. In all transects, lichen species richness and percentage cover increased with distance from the oil refinery, suggesting that indeed lichens are sensitive to pollution and are therefore good air pollution bio-monitors. The fruticose growth forms especially Teloschistes and Usnea were shown in this study to be the most sensitive to pollution because none of them was recorded close to the oil refinery. Photosynthetic pigment analyses revealed that Parmelia and Xanthoria are affected differently by pollution. Parmelia showed chlorophyll a and b injury under high pollution conditions while Xanthoria showed high carotenoid injury. The results of this study indicate that the atmosphere in the Milnerton industrial area is heavily polluted, with the Caltex oil refinery being the main pollution source.

Thesis (M. Sc. (Chemistry)) -- University of Limpopo, 2021 / Water pollution associated with dyes and bacteria has become a concern to researchers due to lack of quality sanitation. South Africa falls amongst the water scarce countries. Thus, it is important to develop materials that can effectively remove a variety of pollutants such as dyes and bacteria. Titanium dioxide (TiO2) and Zinc Oxide (ZnO) are materials that have been shown to have great potential in removing these pollutants since they have both the antibacterial and photocatalytic properties. However, due to their large bandgap, fast recombination rate, selective activity and the use of toxic solvents during the synthesis, a need was identified to improve these materials. In this study, the use of Monsonia burkeana (MB) plant extract for the synthesis of TiO2 and ZnO was conducted, to ensure that environmentally safe products were produced and to assist in the antibacterial activity. Also, carbon nanomaterials were loaded on these metal oxides to assist with the reduction of the recombination rate and increase the active sites to ensure that an enhanced photodegradation process took place. Green synthesised TiO2 and ZnO as antibacterial agents and photocatalyst were investigated and compared. Moreover, carbon based materials decorated with green synthesised metal oxides for photocatalytic degradation of dyes was also conducted. In the first section, TiO2 and ZnO nanoparticles were synthesised using MB extract as a reducing agent. The synthesised TiO2 and ZnO nanoparticles were characterised using UV-vis, FTIR, TEM, SAED, SEM, XRD and TGA. These materials were then tested for their antibacterial and photocatalytic potential. From the results, LC-MS and FTIR provided evidence of the compounds, functional groups and elements that contributed to the mechanism of metal oxide formation. The UV-vis of TiO2 and ZnO nanoparticles exhibited absorbance peaks at 327 and 325 nm, respectively, confirming their formation. In support, FTIR showed vibration bands at the fingerprint region belonging to the metal oxides. SEM showed a spherical shape of TiO2 nanoparticles whereas ZnO nanoparticles exhibited a hexagonal shape. Particle size analysis showed that ZnO nanoparticles had a broad size distribution from 5 to 35 nm and TiO2 had a distribution size from 2 to 18 nm. Thereafter, the metal oxides were tested for their antibacterial and photocatalytic activity. Upon testing their antibacterial potential, ZnO nanoparticles were active against all the four bacterial strains, Staphylococcus iii aureus, Pseudomonas aeruginosa, Enterococcus faecalis and Escherichia coli, while for TiO2 nanoparticles, the strains were resistant and only partially active against Escherichia coli. The water samples collected from tap, sewage, pond and river were tested for their presence of total pollution, Escherichia coli, total coliform and Enterobacteriaceae strains. TiO2 nanoparticles inhibited most of the strains compared to ZnO nanoparticles. For photocatalytic degradation using Methylene blue (MB) as a model pollutant, the TiO2 nanoparticles showed a higher photocatalytic activity than ZnO nanoparticles with a percentage degradation of 85.5% and 61.3%, respectively. The optimum degradation was obtained at pH (10), dosage (60 mg), concentration (20 ppm) and time (120 min). For reusability, the stability behaviour of TiO2 and ZnO nanoparticles gradually decreased with an increase in the number of testing cycles. To improve the activity of TiO2 nanoparticles, carbon based materials (Carbon spheres (CSs) and Carbon nanofibers (CNFs)) were loaded with 5, 10 and 20% of TiO2 and tested for their photocatalytic activity. The 20%TiO2/CSs composite, degraded 88.5% of MB in solution at 120 min. The addition of a low bandgap material, CuO on to the composites (TiO2/CNFs and TiO2/CSs) did not improve the photocatalytic degradation of MB. This study has shown that low cost and safe materials can be produced and can be used to inhibit and degrade various pollutants.

False Bay is the largest (circa 1000km²) natural, coastal embayment on the South African coastline and is located between latitudes 34°04'S and 34°23'S and longitudes 18°26'E and 18°52'E at the southern tip of Africa, near Cape Town, South Africa. The semi-enclosed nature of the bay makes it unsuitable as a 'sink' for all the contaminated urban stormwater run-off and the greatly increased pollution loads entering the bay. All pollution point sources entering False Bay were identified and described, and some of these selected for detailed study, the emphasis being on the impact of some individual discharges on the subtidal macrofauna. The similar biotic characteristics of three subtidal study sites in the region of the Steenbras Water Treatment Plant discharge indicate that the general turbidity and lower salinity characteristics of eastern False Bay are more likely to be responsible for the impoverished diversity near the outfall rather than the aluminium content of the discharge. Toxicity experiments on the bivalves Choromytilus meridionalis, Mytilus galloprovincialis and Perna perna using alum and ferric sludge indicate that there are no significant short-term sub-lethal toxic effects on the rocky shore bivalves and that decreased salinities in the immediate region of the outfall (as a result of the freshwater stream input) may have a more deleterious effect. A study of eighteen subtidal sites in False Bay indicated that overall densities of subtidal macro plastic debris were low, but that there are some 'hot spots' where densities are relatively high viz., Kalk Bay, Strandfontein, Mnandi, Monwabisi and Gordon's Bay. Colonising of debris by benthic organisms does occur, mostly on white plastic. Most of the debris consisted of plastic packaging from local land-based sources, indicating that it originates from wind-blown litter left by beachgoers. The highest density at the Sunnycove Control Site occurred in January during the peak holiday season. A longer term (three years) study of the subtidal environment in the vicinity of the Marine Oil Refiners outfall pipe indicated that the lack of subtidal macro fauna is more likely due to the harsh environmental conditions (abrasion and smothering) rather than the pollution impact of the outfall. This is confirmed by the abundant, healthy and diverse community on the nearby wreck of the Clan Stuart (1917) which indicates a stable ecosystem. The complexity of False Bay - its unique topography, bathymetry, meteorology make it difficult to attain a true climatic or average circulation. This lack of a consistent conceptual overview of the False Bay physical circulation is a short-coming that needs to be urgently addressed if the dangers of pollution inputs are to be accurately assessed. An overall management policy for False Bay should be urgently formulated and an officially constituted body with legislative power is needed if holistic management of the bay is to be achieved and such a prime recreational asset preserved for future generations. Bibliography: pages 195-225.

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