Background: Platinum group metal (PGM) mining and refining is a large constituent of the mining sector of South Africa and contributes significantly to the gross domestic product. The PGMs include the rare metals platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir) and osmium (Os). During the refining process workers are potentially exposed to various chemical forms of the PGMs via the respiratory and dermal exposure routes. Historically, emphasis has been on respiratory exposure while the extent of skin exposure is still unknown. Among the different forms of PGMs, the salts are potential sensitisers, with platinum being a known respiratory sensitiser. Workers occupationally exposed to platinum and rhodium have reported respiratory as well as skin symptoms. However, it is unknown if these metals in the salt form are permeable through human skin, and whether dermal exposure could contribute to sensitisation. Evidence regarding differences between African and Caucasian skin anatomy and structure, as well as permeation through skin is contradictory, and no information is available on metal permeation through African skin. The in vitro diffusion method has been utilised successfully in occupational toxicology to demonstrate that metals such as chromium, cobalt and nickel, to name a few, permeate through human skin. The permeability of platinum and rhodium has not been investigated previously. Aims and objectives: The research aim was to obtain insight into the permeability of platinum and rhodium through intact human skin and to provide information needed to determine the potential health risk following dermal exposure to these metals. The specific objectives included: (i) to critically review the in vitro diffusion method that is used to determine the permeability of metals through human skin, (ii) to investigate the permeation of potassium tetrachloroplatinate (K2PtCl4) and rhodium chloride (RhCl3) as representative PGM salts through intact human skin over a 24-hour period, (iii) to evaluate the difference in permeability of platinum and rhodium through intact human skin, (iv) to evaluate the difference in permeability of platinum through intact African and Caucasian human skin. Methods: Abdominal skin obtained after cosmetic procedures was obtained from five female Caucasian and three female African donors between the ages of 28 and 52 with ethical approval from the North-West University. Full thickness skin tissue was mounted in a vertical Franz diffusion cell. Skin integrity was tested by measuring the electrical resistance across the skin before and after conclusion of the experiments, using a Tinsley LCR Data bridge Model 6401. The donor solution of 32.46 mg K2PtCl4 in 50 ml of synthetic sweat (pH 6.5), and 43.15 mg RhCl3 in 50 ml of synthetic sweat (pH 6.5) was prepared. The donor solution was applied to the stratum corneum side of the skin and physiological receptor solution (pH 7.35) was added to the receptor compartment. The concentration of the metals in the receptor solution was determined by high resolution inductively coupled plasma-mass spectrometry after extraction at various intervals during the 24 hours of the study. After completion of the study, the skin was rinsed four times to remove any platinum or rhodium remaining on the skin surface. The skin was digested using hydrogen peroxide, nitric acid and hydrochloric acid during different steps to determine the mass of the metals remaining in the skin by inductively coupled plasma-optical emission spectrometry. Results: The comparison of published in vitro skin permeation studies involving metals is impeded by the variations in the experimental design and dissimilarity in the reporting of results. Differences in experimental design included, most noticeably, the use of various donor and receptor solutions, different temperatures wherein the receptor compartment was placed, differences in skin thickness and variations in exposed skin surface areas. The metals considered in the review, namely chromium, cobalt, gold, lead, mercury, nickel, platinum, rhodium and silver, permeate through intact human skin under physiological conditions. Large variations in the permeability results were observed, with the notable differences in methodology as the probable reason. Results obtained from the in vitro experiments indicate that platinum and rhodium permeated through intact Caucasian skin with flux values of 0.12 and 0.05 ng/cm2/h, respectively. The cumulative mass of platinum (2.57 ng/cm2) that permeated after 24 hours of exposure was statistically significantly (p = 0.016) higher than rhodium permeation (1.11 ng/cm2). The mass of platinum (1 459.47 ng/cm2) retained in the skin after 24 hours of exposure was statistically significantly (p < 0.001) higher than rhodium retention (757.04 ng/cm2). The comparison of permeability between two different racial groups indicates that platinum permeated through the skin of both racial groups with the flux through African skin found as 1.93 ng/cm2/h and 0.27 ng/cm2/h through Caucasian skin. The cumulative mass of platinum permeated after 24 hours of exposure was statistically significantly (p = 0.044) higher through African skin (37.52 ng/cm2) than Caucasian skin (5.05 ng/cm2). The retention of platinum in African skin (3 064.13 ng/cm2) was more than twice the mass retained in Caucasian skin (1 486.32 ng/cm2). Conclusions: The in vitro diffusion method is an applicable method to determine skin permeability of metals. However, the experimental design and format of data reporting should be standardised to enable comparison of results from different studies. Platinum and rhodium permeated through intact human skin, with platinum permeation significantly higher. African skin was significantly more permeable by platinum than Caucasian skin. Both platinum and rhodium were retained inside the skin after 24 hours of exposure, possibly forming a reservoir which could contribute to continued permeation through the skin even after removal thereof from the skin. Platinum and rhodium permeated through full thickness skin and thereby could possibly contribute to local skin symptoms such as dermatitis and urticaria found in occupationally exposed workers. By permeating through the upper layers of the skin, these metals could potentially reach the viable epidermis and contribute to sensitisation. / PhD (Occupational Hygiene), North-West University, Potchefstroom Campus, 2015

The study attempted to quantify the elemental concentrations and possible accumulation levels in the antelope's organ tissue at Rheinmetal Denel Munitions (RDM), as well as to correlate the findings with the surrounding environment. To achieve this, the elemental concentrations within the kidney, liver and lung tissue of the antelope, and environmental factors such as the soil, vegetation and waterholes were quantified. STATISTICA was used to determine meaningful differences between variables and Canoco to determine the relationship between the different datasets. PCA analyses of the vegetation confirmed that the natural slope at RDM could have contributed to the distribution and variation of the elemental concentration. It became apparent that positive associations existed between the liver tissue and the K, the kidney tissue and Ni and Cd, and the lung tissue had a positive association with Mg, Mn, V, Rb and Co elemental concentrations. It became evident in this study that the elemental concentrations of Al and Ni were higher in the liver and kidney tissue of the antelope than the recommended concentration for livestock (Puls, 1994). The elemental concentration of Al, Ca, Fe and Mn also exceeded the recommended elemental concentration for livestock, in the water sampled at RDM (Puls, 1994). Four distinct areas were identified within the study area, the area above the factory, the area under the factory, the testing area and the area under the factory. Significant differences between the testing area and the area under the factory were found regarding the Tl, Ag, Hg and B elemental concentrations in the vegetation. Furthermore, it became apparent that the amount of precipitation could have contributed to the variation of the elemental concentrations and distribution in the study area as well as in the organ tissue of the antelope. / Thesis (M.Sc. (Environmental Science and Management))--North-West University, Potchefstroom Campus, 2011.

The study attempted to quantify the elemental concentrations and possible accumulation levels in the antelope's organ tissue at Rheinmetal Denel Munitions (RDM), as well as to correlate the findings with the surrounding environment. To achieve this, the elemental concentrations within the kidney, liver and lung tissue of the antelope, and environmental factors such as the soil, vegetation and waterholes were quantified. STATISTICA was used to determine meaningful differences between variables and Canoco to determine the relationship between the different datasets. PCA analyses of the vegetation confirmed that the natural slope at RDM could have contributed to the distribution and variation of the elemental concentration. It became apparent that positive associations existed between the liver tissue and the K, the kidney tissue and Ni and Cd, and the lung tissue had a positive association with Mg, Mn, V, Rb and Co elemental concentrations. It became evident in this study that the elemental concentrations of Al and Ni were higher in the liver and kidney tissue of the antelope than the recommended concentration for livestock (Puls, 1994). The elemental concentration of Al, Ca, Fe and Mn also exceeded the recommended elemental concentration for livestock, in the water sampled at RDM (Puls, 1994). Four distinct areas were identified within the study area, the area above the factory, the area under the factory, the testing area and the area under the factory. Significant differences between the testing area and the area under the factory were found regarding the Tl, Ag, Hg and B elemental concentrations in the vegetation. Furthermore, it became apparent that the amount of precipitation could have contributed to the variation of the elemental concentrations and distribution in the study area as well as in the organ tissue of the antelope. / Thesis (M.Sc. (Environmental Science and Management))--North-West University, Potchefstroom Campus, 2011.

Text in English with abstracts in English, Afrikaans and isiXhosa / The collections-based research reported upon in this dissertation focuses on three sites in the Eastern Cape: Huntley Street in Grahamstown, Farmerfield, a nearby Wesleyan mission station, and Fort Double Drift, a British fortification on the Great Fish River. The collection, which is housed in the Albany Museum, derives from Patrice Jeppson’s excavations, completed in the 1980s. Analyses of the excavated glass and metal, augmented by a close reading of tender and shopkeepers’ advertisements in The Graham’s Town Journal, chronicle how merchants, settlers, soldiers, missionaries and local African communities were involved in, and affected by, trade between 1820 and 1860. The study explores aspects of the mercantile economy, consumerism and military provisioning relating to a wide range of imported glass and metal merchandise. The burgeoning trade linked various enterprises, groups and individuals through monetary and social transactions, reflecting the steady incorporation of the Eastern Cape into the British colonial trading network. / Die versamelingsgebaseerde navorsing waaroor in hierdie verhandeling verslag gedoen word, fokus op drie terreine in die Oos-Kaap: Huntley-straat in Grahamstad, Farmerfield, ’n nabygeleë Wesleyaanse sendingstasie, en Fort Dubbeldrif ’n Britse vesting aan die Groot-Visrivier. Die versameling, wat in die Albany-museum gehuisves word, is afkomstig van Patrice Jeppson se opgrawings, wat in die 1980's voltooi is. Ontledings van die opgegraafde glas en metaal, aangevul deur ’n grondige studie van tender- en winkelieradvertensies in The Graham’s Town Journal, boekstaaf hoe handelaars, setlaars, soldate, sendelinge en plaaslike Afrika-gemeenskappe by handel tussen 1820 en 1860 betrokke was, en daardeur beïnvloed is. Die studie verken aspekte van die handelsekonomie, verbruikerisme en militêre bevoorrading met betrekking tot ’n wye verskeidenheid ingevoerde glas- en metaalhandelsware. Die bloeiende handel het verskeie ondernemings, groepe en individue deur monetêre en sosiale transaksies met mekaar verbind, wat die geleidelike opname van die Oos-Kaap in die Britse koloniale handelsnetwerk weerspieël. / Uphando lwezinto eziqokelelweyo ekunikwe ingxelo ngalo kule disetheyishini, lugxile kwiindawo ezintathu eziseMpuma Koloni ezizezi: eHuntley Street eRhini, eFarmerfield, esisitishi seMishini yamaWesile, naseFort Double Drift, eyinqaba yamaBhilitane ekwiGreat Fish River. Le ngqokelela, egcinwe eAlbany Museum, isuka kwizinto ezazigrunjwe nguPatrice Jeppson, grunjo olo olwagqitywa phaya koo1980. Uphononongo lweeglasi neentsimbi ezagronjwayo, oluxhaswa nakukufundwa kweentengiso ezakhutshwayo zeethenda nezoonovenkile kwi-The Graham’s Town Journal, lunika iinkcukacha zeendlela abarhwebi, abemi ababesuka kwamanye amazwe aphesheya kweelwandle, abefundisi ababesuka kwamanye amazwe, amajoni noluntu olumnyama lwaloo mimandla ababebandakanyeka ngayo nebabechatshazelwa ngayo lurhwebo olwaqhubeka phakathi ko-1820 no-1860. Olu phando luvelela imiba yoqoqosho lorhwebo, ukhuselo lwabathengi, nobonelelo lwezinto zomkhosi lwezinto eziliqela zeeglasi nezentsimbi. Olu rhwebo olwaluhlumile lwahlanganisa amashishini ahlukileyo, amaqela kunye nabantu nje abazimeleyo ngokuthi barhwebelane ngeemali nangezinto zentlalo, yaye oku kubonisa ukungeniswa kweMpuma Koloni kuthungelwano lorhwebo lobukoloniya lwamaBhilitane. / Anthropology and Archaeology / M.A. (Archaeology)