Silica is a common silicon dioxide (SiO2) that can be crystalline or non-crystalline (amorphous). Amorphous silica is considered to be less hazardous than crystalline silica. Three dominant crystalline polymorphs exist, with silica quartz being the most common. Exposure to respirable crystalline silica (quartz) causes silicosis, a lung scarring disease. The aim of this study was to identify and quantify the silica exposure in respirable dust personal exposure samples, as well as in representative bulk samples which are large samples taken from the sources of airborne dust obtained from different mining and production plants involved in the production of titanium dioxide from beach sand. This is needed to determine the degree of risk of developing silicosis. Forty five workers employed in different mining and production plants participated in this study. Their eight-hour personal exposure to respirable particulate was determined. Personal respirable dust exposure samples and bulk samples were analyzed for silica by an accredited laboratory by means of X-ray diffraction based on NIOSH method 7500. Silica quartz was detected in personal respirable dust samples and bulk dust samples obtained from the mining and production plants, but amorphous silica was only detected in three personal exposure samples at the Slag plant and in the bulk sample obtained from the Roaster plant. All the silica quartz and amorphous silica concentrations in personal exposure samples were well below their respective exposure limits of 0.1 mg/m3 (quartz) and 3 mg/m3 (amorphous). No significant differences were found between the silica quartz concentrations in personal respirable exposure samples obtained from the mining ponds and the production plants, although a practical significance was found between some mining and production area personal exposure samples. The non-significant differences found between exposure concentrations and a practical significance suggest the necessity of involving a larger sample group in future. Other studies done in non-mining industries showed that some workers were over exposed to respirable silica dust. Compared to these findings the results of the present study showed the opposite, with respirable silica dust levels being below the South African action level and OEL. Further research, involving more samples, spread over a longer period of time, would probably be able to show a clear trend as to how quartz structures and exposure profiles change from the mining to the various production processes. Overexposure to silica quartz anywhere at the mine and production processes is considered unlikely, with the risk of developing silicosis being low. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013

Silica is a common silicon dioxide (SiO2) that can be crystalline or non-crystalline (amorphous). Amorphous silica is considered to be less hazardous than crystalline silica. Three dominant crystalline polymorphs exist, with silica quartz being the most common. Exposure to respirable crystalline silica (quartz) causes silicosis, a lung scarring disease. The aim of this study was to identify and quantify the silica exposure in respirable dust personal exposure samples, as well as in representative bulk samples which are large samples taken from the sources of airborne dust obtained from different mining and production plants involved in the production of titanium dioxide from beach sand. This is needed to determine the degree of risk of developing silicosis. Forty five workers employed in different mining and production plants participated in this study. Their eight-hour personal exposure to respirable particulate was determined. Personal respirable dust exposure samples and bulk samples were analyzed for silica by an accredited laboratory by means of X-ray diffraction based on NIOSH method 7500. Silica quartz was detected in personal respirable dust samples and bulk dust samples obtained from the mining and production plants, but amorphous silica was only detected in three personal exposure samples at the Slag plant and in the bulk sample obtained from the Roaster plant. All the silica quartz and amorphous silica concentrations in personal exposure samples were well below their respective exposure limits of 0.1 mg/m3 (quartz) and 3 mg/m3 (amorphous). No significant differences were found between the silica quartz concentrations in personal respirable exposure samples obtained from the mining ponds and the production plants, although a practical significance was found between some mining and production area personal exposure samples. The non-significant differences found between exposure concentrations and a practical significance suggest the necessity of involving a larger sample group in future. Other studies done in non-mining industries showed that some workers were over exposed to respirable silica dust. Compared to these findings the results of the present study showed the opposite, with respirable silica dust levels being below the South African action level and OEL. Further research, involving more samples, spread over a longer period of time, would probably be able to show a clear trend as to how quartz structures and exposure profiles change from the mining to the various production processes. Overexposure to silica quartz anywhere at the mine and production processes is considered unlikely, with the risk of developing silicosis being low. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013

Philosophiae Doctor - PhD / This study presents the results of radiometric investigation of soil and beach sand in Zanzibar. The activity concentration of natural radionuclides (40K, and 232Th and 238U decay products) in beach sand and soil samples was measured in-situ using the NaI(Tl) and the MEDUSA gamma ray detectors and ex-situ using the low background HPGe detector system. The activity concentrations of 232Th, 238U and 40 K in beach sand are much lower than in soil samples, with one major exception at Kukuu. Two beach sand samples from Kukuu beach were found to have enhanced radioactivity levels due to the presence of heavy minerals. The spatial distributions maps for 40K, 238U and 232Th show large variation in soil samples for two relatively small islands. These strong variations are unexpected, that could have implications for agriculture, is one of the major outcomes of this study. The outdoor gamma dose rates obtained in beach sand and soil samples ranged from 3 to 2156 nGy h-1 and 50 to 294 nGy h-1, respectively. The highest absorbed dose rates in soil samples and beach sand are respectively 5 and 38 times higher than the average world level of 57 nGyh-1 for terrestrial doses (UNSCEAR, 2008). Apart from the Kukuu black sand samples that contain the high 238U and 232Th levels, the beach sands and soil in this study do not pose any radiological threat to the public using beaches for various activities. Based on elemental concentrations, the beach samples in the study area have been classified into four groups; silicate sand (rich in SiO2), carbonate sand (dominated with CaO), mixed sand (with high amount of CaO and SiO2) and heavy mineral sand (with high contents of Fe2O3 and TiO2. A strong correlation between SiO2, Fe2O3, TiO2, Zr, V, Ce, Nb, Hf, Y, La, and Nd show these elements are linked with high activity concentration of 232Th in the studied samples. Moreover, the high concentrations of Y, V, P2O5 and Fe2O3 in the beach sand samples may relate to high 238U activity concentration. This study set out to investigate how radiometric studies can quickly and easily provide an idea of the variation of soil type found over a large area as well as provide detailed information on a small scale such as the beach where heavy minerals were found. The in-situ laboratory measurements were supplemented by XRF and ICP-MS measurements of samples to investigate the distribution of heavy mineral sands.

yes / This paper presents field measurements in which dye solute was injected into coastal sand to investigate contaminant advection in intertidal beach sand. The measurements show the pathways of a contaminated plume in the unsaturated zone during both the flood and ebb tides. A prescribed amount of dye tracer solution was directly injected through the topsoil, with average porosity 0.3521±0.01, at predetermined locations of the River Mersey’s outer estuarial beach during ebb-tide. The injected dye was monitored, sampled and photographed over several tidal cycles. The distinctive features of the plume (full two dimensional cross-sections), sediments and water-table depth were sampled in-situ, close to the injection point (differing from previous contaminant monitoring tests in aquifers). The advective movement is attributed to tidal impact which is different from contaminant transport in aquifers. The experimental results show that plumes have significantly large spatial variability, diverging upwards and converging downwards, with a conical geometric shape which is different from the usual spherical/elliptical shape reported in literature. The mean vertical motion of the plume reaches three times the top-width within ten tidal cycles, exceeding the narrow bottom-width by a factor of order 2. The observed transport features of the plume within the beach sand have significant relevance to saltwater intrusion, surface water and groundwater quality. The field observations are unique and can serve as a valuable benchmark database for relevant numerical studies. / China Ministry of Science and Technology 973 program (2014CB745001), Special Program of future development in Shenzhen (201411201645511650) and Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment（ZDSY20130402163735964).

<p><font face="TimesNewRomanPSMT"> <p align="left">Natural radioactivity studies have been carried out to study the textural characteristics, heavy mineral composition, provenance, sediment transport, and depositional environment of beach placer deposits. The naturally occurring radionuclides such as properties of beach sands, which reflect the geological characteristics such as transport and sorting processes and the depositional environment. The present work focuses on the radiometric characteristics of beach sand deposits along the west coastof South Africa. Beach sands samples were collected at the Melkbosstrand (MBS) and Ouskip (OSK) beach. The activity concentrations of these radionuclides were determined by high-resolution gamma-ray spectrometry using a high-purity germanium (HPGe) detector in a low-background configuration.</p> </font></p>

<p><font face="TimesNewRomanPSMT"> <p align="left">Natural radioactivity studies have been carried out to study the textural characteristics, heavy mineral composition, provenance, sediment transport, and depositional environment of beach placer deposits. The naturally occurring radionuclides such as properties of beach sands, which reflect the geological characteristics such as transport and sorting processes and the depositional environment. The present work focuses on the radiometric characteristics of beach sand deposits along the west coastof South Africa. Beach sands samples were collected at the Melkbosstrand (MBS) and Ouskip (OSK) beach. The activity concentrations of these radionuclides were determined by high-resolution gamma-ray spectrometry using a high-purity germanium (HPGe) detector in a low-background configuration.</p> </font></p>

Magister Scientiae - MSc / Natural radioactivity studies have been carried out to study the textural characteristics, heavy mineral composition, provenance, sediment transport, and depositional environment of beach placer deposits. The naturally occurring radionuclides such as 232Th, 238U and 40K are used as the tracers of the mineralogical properties of beach sands, which reflect the geological characteristics such as transport and sorting processes and the depositional environment. The present work focuses on the radiometric characteristics of beach sand deposits along the west coast of South Africa. Beach sands samples were collected at the Melkbosstrand (MBS) and Ouskip (OSK) beach. The activity concentrations of these radionuclides were determined by high-resolution gamma-ray spectrometry using a high-purity germanium (HPGe) detector in a low-background configuration.

O Brasil possui em sua área costeira grandes metrópoles onde diversas atividades humanas são desenvolvidas, podendo trazer prejuízos à qualidade das águas costeiras. O litoral de São Paulo, constituído por 16 municípios incluindo-se Cubatão, apresenta peculiaridades diferenciadas. O tipo de poluição mais encontrado na costa paulista é a poluição fecal causada por despejo de esgotos domésticos, os quais transportam organismos patogênicos cuja presença pode levar a agravos à saúde humana. O objetivo deste estudo é o de avaliar a qualidade sanitária de águas e areias de praias da Baixada Santista. Assim amostras de água e areia (úmida e seca) de três praias, como Gonzaguinha (São Vicente), Boqueirão (Santos) e Pitangueiras (Guarujá) foram coletadas com freqüência mensal pelo período de um ano nas quais foram analisados os seguintes parâmetros: coliformes termotolerantes, Escherichia coli, enterococos, e ainda Staphylococcus coagulase (+), Pseudomonas aeruginosa, Candida albicans e dermatófitos. Para a realização das análises em amostras de água utilizou-se da Técnica da Membrana Filtrante e para as amostras de areia a Técnica de Tubos Múltiplos, de acordo com Normas Técnicas CETESB e Standard Methods. Para a determinação de dermatófitos, as amostras de água foram concentradas pela Técnica de Membrana Filtrante e as amostras de areia (seca e úmida) foram analisadas pela Técnica de inoculação em superfície e, concomitantemente, pela Técnica da Isca de Cabelo. Os resultados obtidos revelaram que 95 por cento das amostras analisadas foram positivas para a presença dos indicadores de contaminação fecal, seguidos por P. aeruginosa, presente em 75 por cento das amostras. C. albicans foi o microrganismo menos freqüente (6,7 por cento) e foi detectada somente nas amostras de água. O dermatófito Microsporum sp foi detectado somente nas amostras de areia e esteve presente nas três praias. De maneira geral, o comportamento das concentrações dos microrganismos foi maior nas amostras de areia seca, independentemente dos eventos de chuva, seguidas pela areia úmida, sendo as menores concentrações observadas nas amostras de água. Concluiu-se que as concentrações dos microrganismos indicadores de poluição fecal e dos patogênicos foram elevadas nas matrizes estudadas e que é necessário dirigir esforços para a melhoria da qualidade das águas e areias, pois as condições observadas trazem preocupação à saúde dos banhistas e freqüentadores das praias / Brazilian seashore comprises many big cities and the diverse activities which are performed in these areas can bring damages to seashore water quality. São Paulo State seashore comprises 16 cities including Cubatão, where each one shows their own particularities. In the São Paulo State seashore is mostly observed fecal pollution due to launching sewage into these waters which transport pathogens with potential to cause diseases. The objective of this study is to assess the sanitary quality of recreational waters and wet and dry sand from three beaches located at Baixada Santista such as Gonzaguinha (São Vicente), Boqueirão (Santos) and Pitangueiras (Guarujá). The samples (water, wet and dry sand) were collected with monthly frequency throughout a year and the following parameters were analyzed: thermotolerant coliforms, Escherichia coli, enterococos, Staphylococcus coagulase +, Pseudomonas aeruginosa, Candida albicans and dermatophytes. The bacteriological and C. albicans analyzes were performed according to CETESB and Standard Methods 21st edition. Dermatophyte analysis from water samples were carried out by membrane filtering technique and by spread plate technique and hair-baiting technique for sand samples. The results revealed that 95 per cent of the water samples were positive for fecal indicators following by P. aeruginosa (75 per cent). C. albicans was detected only in water samples showing 6.7 per cent of the observed frequency. Microsporum sp specie was detected only in sand samples in all beaches studied. In general, high microorganisms concentrations was found in dry sand samples regardless raining events, following by wet sand and the lowest concentrations were found in water samples. It was possible to conclude that fecal indicators microorganisms and pathogens concentrations were high in all samples analyzed and it highlights to necessity to address efforts to improve the quality of the water and sand because this poor quality condition found poses a significant public health concern

O Brasil possui em sua área costeira grandes metrópoles onde diversas atividades humanas são desenvolvidas, podendo trazer prejuízos à qualidade das águas costeiras. O litoral de São Paulo, constituído por 16 municípios incluindo-se Cubatão, apresenta peculiaridades diferenciadas. O tipo de poluição mais encontrado na costa paulista é a poluição fecal causada por despejo de esgotos domésticos, os quais transportam organismos patogênicos cuja presença pode levar a agravos à saúde humana. O objetivo deste estudo é o de avaliar a qualidade sanitária de águas e areias de praias da Baixada Santista. Assim amostras de água e areia (úmida e seca) de três praias, como Gonzaguinha (São Vicente), Boqueirão (Santos) e Pitangueiras (Guarujá) foram coletadas com freqüência mensal pelo período de um ano nas quais foram analisados os seguintes parâmetros: coliformes termotolerantes, Escherichia coli, enterococos, e ainda Staphylococcus coagulase (+), Pseudomonas aeruginosa, Candida albicans e dermatófitos. Para a realização das análises em amostras de água utilizou-se da Técnica da Membrana Filtrante e para as amostras de areia a Técnica de Tubos Múltiplos, de acordo com Normas Técnicas CETESB e Standard Methods. Para a determinação de dermatófitos, as amostras de água foram concentradas pela Técnica de Membrana Filtrante e as amostras de areia (seca e úmida) foram analisadas pela Técnica de inoculação em superfície e, concomitantemente, pela Técnica da Isca de Cabelo. Os resultados obtidos revelaram que 95 por cento das amostras analisadas foram positivas para a presença dos indicadores de contaminação fecal, seguidos por P. aeruginosa, presente em 75 por cento das amostras. C. albicans foi o microrganismo menos freqüente (6,7 por cento) e foi detectada somente nas amostras de água. O dermatófito Microsporum sp foi detectado somente nas amostras de areia e esteve presente nas três praias. De maneira geral, o comportamento das concentrações dos microrganismos foi maior nas amostras de areia seca, independentemente dos eventos de chuva, seguidas pela areia úmida, sendo as menores concentrações observadas nas amostras de água. Concluiu-se que as concentrações dos microrganismos indicadores de poluição fecal e dos patogênicos foram elevadas nas matrizes estudadas e que é necessário dirigir esforços para a melhoria da qualidade das águas e areias, pois as condições observadas trazem preocupação à saúde dos banhistas e freqüentadores das praias / Brazilian seashore comprises many big cities and the diverse activities which are performed in these areas can bring damages to seashore water quality. São Paulo State seashore comprises 16 cities including Cubatão, where each one shows their own particularities. In the São Paulo State seashore is mostly observed fecal pollution due to launching sewage into these waters which transport pathogens with potential to cause diseases. The objective of this study is to assess the sanitary quality of recreational waters and wet and dry sand from three beaches located at Baixada Santista such as Gonzaguinha (São Vicente), Boqueirão (Santos) and Pitangueiras (Guarujá). The samples (water, wet and dry sand) were collected with monthly frequency throughout a year and the following parameters were analyzed: thermotolerant coliforms, Escherichia coli, enterococos, Staphylococcus coagulase +, Pseudomonas aeruginosa, Candida albicans and dermatophytes. The bacteriological and C. albicans analyzes were performed according to CETESB and Standard Methods 21st edition. Dermatophyte analysis from water samples were carried out by membrane filtering technique and by spread plate technique and hair-baiting technique for sand samples. The results revealed that 95 per cent of the water samples were positive for fecal indicators following by P. aeruginosa (75 per cent). C. albicans was detected only in water samples showing 6.7 per cent of the observed frequency. Microsporum sp specie was detected only in sand samples in all beaches studied. In general, high microorganisms concentrations was found in dry sand samples regardless raining events, following by wet sand and the lowest concentrations were found in water samples. It was possible to conclude that fecal indicators microorganisms and pathogens concentrations were high in all samples analyzed and it highlights to necessity to address efforts to improve the quality of the water and sand because this poor quality condition found poses a significant public health concern