Thesis (MSc)--University of Stellenbosch, 2007. / Bibliography.

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

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Batch tests were performed to evaluate the relative performance of four B.C. coals (Hat Creek Oxidised, Kaiser-stock pile refuse, Kaiser-special plant feed and Cominco Ash) in removing heavy metals copper, lead, zinc and mercury from filtered primary sewage treatment plant effluent. Emphasis was placed on metal concentrations of 10 mg/l and less. Hat Creek coal was found to be much superior to the other three and its efficiency is comparable to that of Darco activated carbon 12 x 20. Hat Creek and Kaiser-stock pile refuse coals were further used in column tests to evaluate the relative performance of these coals in removing copper, lead and zinc under dynamic conditions. Again emphasis was placed on influent metal concentrations of 10 mg/1 and less and once more the performance of Hat Creek coal was much superior to that of Kaiser coal. Tests with activated carbon indicate Hat Creek coal to be a close competitor for use in advanced waste treatment for heavy metal removal. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Levels and dietary intake of heavy metals were assessed and evaluated in thirty two samples of fruit and vegetables collected from supermarkets in Accra, Ghana using atomic absorption spectroscopy. Differences (p <= 0.05) existed in Pb, Cd and Ni concentrations across the commodities collected. Levels of Pb, Cd and Cr exceeded safe limits established by FAO and EU. Washing reduced Cr in cabbage by 59% (p <= 0.05) but only reduced Pb in grapes by 12% (p ˃ 0.05). Estimated daily and weekly intake through fruit and vegetable consumption were below provitional tolerable dietary intake established by the FAO. Although estimated dietary intake obtained in this study were below the maximum established limits, increased comsumption of these fruit and vegetables may bring about adverse health implications for the exposed population.

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Submitted in partial fulfillment of the requirements for the degree in Masters of Technology: Chemistry, ML Sultan Technikon, Durban, 2003. / The pollution of water bodies by heavy metals is a serious threat to humanity. The technique known as phytoremediation is used to clean up these polluted water bodies. The accumulation of heavy metals by aquatic plants is a safer, . cheaper and friendlier manner of cleaning the environment. The aquatic plants -studied in this project are A.sessilis, P.stratiotes, R.steudelii and T.capensis. The accumulation of heavy metals in aquatic plants growing in waste water treatment ponds was investigated. The water, sludge and plants were collected from five maturation ponds at the Northern Waste Water Treatment Works, Sea Cow Lake, Durban. The samples were analysed for Zn, Mn, Cr, Ni, Pb and Cu using ICP-MS. In general it was found that the concentrations of the targeted metals were much lower in the water (0.002 to 0.109 mg/I) compared to sediment/sludge (44 to 1543mg/kg dry wt) and plants (0.4 to 2246 mg/kg dry wt). These results show that water released into the river from the final maturation pond has metal concentrations well below the maximum limits set by international environmental control bodies. It also shows that sediments act as good sinks for metals and that plants do uptake metals to a significant extent. Of the four plants investigated it was found that }t.sessi[ir (leaves, roots and stems) and }A.sessilis (roots and stems) are relatively good collectors of Mn and Cu respectively. These findings are described in the thesis. The concentration of heavy metals in the stems, leaves and roots of the three plants were compared to ascertain if there were differences in the ability of the plant at different parts of the plant to bioaccumulate the six heavy metals studied. / M