A combinação do teste de Ames e métodos seletivos de extração para os principais grupos de compostos responsáveis pela atividade genotóxica em amostras ambientais tem sido muito utilizada. O objetivo foi validar o uso do Blue rayon como alternativa para extração de compostos presentes em águas brutas e tratadas. Foram realizados experimentos comparativos entre o Blue rayon e XAD-4 com amostras fortificadas e amostras reais. Dois mananciais, um contaminado com compostos policíclicos e outro não, foram estudados. As amostras foram extraídas com resina XAD4, e com Blue rayon, este último seletivo para compostos policíclicos. Os extratos foram testados com as linhagens de Salmonella typhimurium TA98 e TA100 na presença e ausência de mistura S9. O Blue rayon foi menos eficiente na detecção da mutagenicidade total das amostras quando comparado com a XAD-4. Porém foi capaz de distinguir a mutagenicidade já presente na água bruta daquela gerada durante o tratamento. / The combination of the Ames test and selective extraction methodologies has been successfully used to indicate the possible classes of organic contaminants in environmental samples. The aim of this study was to validate the use of Blue rayon as an alternative extraction method to detect compounds in raw and treated waters. Two different water bodies were evaluated and in one of the sites, raw waters were known to be contaminated with polycyclic compounds. Experiments comparing the Blue rayon technique with XAD-4 resin were done in environmental and spiked samples. The extracts were tested for mutagenicity with Salmonella typhimurium strains TA98 and TA100, with and without metabolic activation. Blue rayon was less efficient in detecting the overall mutagenicity of the samples analyzed in comparison with XAD-4. It was able though to distinguish the mutagenicity due to the contaminants in raw from the ones generated by water treatment.

A combinação do teste de Ames e métodos seletivos de extração para os principais grupos de compostos responsáveis pela atividade genotóxica em amostras ambientais tem sido muito utilizada. O objetivo foi validar o uso do Blue rayon como alternativa para extração de compostos presentes em águas brutas e tratadas. Foram realizados experimentos comparativos entre o Blue rayon e XAD-4 com amostras fortificadas e amostras reais. Dois mananciais, um contaminado com compostos policíclicos e outro não, foram estudados. As amostras foram extraídas com resina XAD4, e com Blue rayon, este último seletivo para compostos policíclicos. Os extratos foram testados com as linhagens de Salmonella typhimurium TA98 e TA100 na presença e ausência de mistura S9. O Blue rayon foi menos eficiente na detecção da mutagenicidade total das amostras quando comparado com a XAD-4. Porém foi capaz de distinguir a mutagenicidade já presente na água bruta daquela gerada durante o tratamento. / The combination of the Ames test and selective extraction methodologies has been successfully used to indicate the possible classes of organic contaminants in environmental samples. The aim of this study was to validate the use of Blue rayon as an alternative extraction method to detect compounds in raw and treated waters. Two different water bodies were evaluated and in one of the sites, raw waters were known to be contaminated with polycyclic compounds. Experiments comparing the Blue rayon technique with XAD-4 resin were done in environmental and spiked samples. The extracts were tested for mutagenicity with Salmonella typhimurium strains TA98 and TA100, with and without metabolic activation. Blue rayon was less efficient in detecting the overall mutagenicity of the samples analyzed in comparison with XAD-4. It was able though to distinguish the mutagenicity due to the contaminants in raw from the ones generated by water treatment.

Thesis. (M. Tech (Biotechnology, Faculty of Applied and Computer Science))--Vaal University of Technology, 2011. / Bottled water like any drinking water used for human consumption should be safe and wholesome to ensure adequate public health protection. This is due to potential health effects of concern such as endocrine disruption, toxicity teratogenicity, mutagenicity and carcinogenicity. Despite the number of regulatory bodies, publications on bottled water and speculations on its public health significance, many questions remain to be answered. One of the questions is whether the shelf life of bottled water is a cause for concern. The aim of the study was to determine the shelf-life of various commercial bottled waters by monitoring the variation in microbiological, chemical and aesthetic qualities of bottled water. A total of five commercial bottled water brands (A, B, C, D, E) each containing bottles from the same batch consisting of spring water, mineral water and bottled tap water were purchased directly after being bottled from different distributors around Gauteng in South Africa. All samples were stored at room temperature with artificial lighting and controlled temperature for a year thus mimicking typical conditions in retail outlets, supermarkets and in homes. Analyses were conducted over a period of 12 months, at monthly intervals. Within days of being purchased, high Heterotrophic plate counts (HPC) bacteria exceeding drinking water alert level >5 000 cfu/ml was common in four bottled water brands. Growth succession occurred during the period of study as various algal species were growing and accumulating on all bottled water tested. Total coliforms (TC), faecal coliforms (FC) and E.coli were not detected in all the bottled water tested. Yeasts and moulds were also not detected in all the bottled water. There were insignificant variations during the period of study for turbidity, pH, TDS, conductivity, and colour. These did not indicate any potential impact on aesthetic quality of bottled water. Two bottled water brands had hardness measures as low as 11mg/ℓ as CaCO3 making the water too soft which has an effect on taste. Radioactive substances, trihalomethanes, heavy metals, pesticides and other chemical contaminants were not found at levels that can be detrimental to human health.

Foram estudadas as propriedades ácido-base de alguns polieletrólitos de interesse ambiental; no sentido de se avaliar a adequabilidade do modelo de sítios discretos na determinação e caracterização dos grupos ionizáveis presentes nestas macromoléculas. Estudou-se os seguintes sistemas de polieletrólitos: ácido húmico comercial (Aldrich) e extraído de vermicomposto (Humus de minhoca); microalga Spirulina (cianobactéria), ácido algínico e ácido poliacrílico de massas molares 2000 e 250000g/mol. Foram realizadas titulações potenciométricas alcalimétricas em diferentes meios iônicos à 25°C com os compostos acima citados. Os dados obtidos foram tratados por linearização (Funções de Gran Modificadas) e regressão não-linear. Os resultados obtidos pelo ácido húmico extraído de vermicomposto (humus de minhoca) e da microalga Spirulina mostraram-se indepentes da força iônica; indicando que o modelo de sítios discretos representa adequadamente os dados experimentais. Para as demais amostras, a estequiometria dos grupos determinados mostrou-se independente do meio iônico, porém os valores de pKa foram bastante afetados, devido à forte influência das interações eletrostáticas decorrentes da acumulação de cargas sobre as macromoléculas durante as titulações. Comparativamente os resultados obtidos tanto por regressão não linear como pelas Funções de Gran modificadas foram similares. / Acid base properties of some polyeletrolytes and colloidal suspensions were studied to evaluate the suitability of discrete site distribution model to fit potentiometric data for determination and characterization of ionizable groups presents in these materials. The polyelectrolytes studied were: commercial humic acid from Aldrich, humic acid isolated from vermicompost, mixed species of microalgae Spirulina, alginic acid and polyacrylic acid of molar masses 2000 and 250000 g/mol. Potentiometric titrations were performed in different ionic media to evaluate the effect of eletrostatic interactions on the titration data. Titrations were perfomed at 25°C, and the data were treated bya linear method based on Modified Gran Functions, as well as by a multiparametric Non-Linear Regression method. The results obtained for the vermicompost humic acid and Spirulina were independent of the ionic strength, suggesting that the chemical heterogeneity plays the major role in the acid base properties of these materials. Thus, the discrete site distribution model is well suited to characterize these materials. For the other polyelectrolytes studied, the influence of eletrostatic interactions was noticed. The discrete site distribution model was able to determine the total stoichiometry of the ionizable groups, but the ionization constants and the distribution of site concentration were dependent on the ionic strength and molar mass of these polyelectrolyte.

Foram estudadas as propriedades ácido-base de alguns polieletrólitos de interesse ambiental; no sentido de se avaliar a adequabilidade do modelo de sítios discretos na determinação e caracterização dos grupos ionizáveis presentes nestas macromoléculas. Estudou-se os seguintes sistemas de polieletrólitos: ácido húmico comercial (Aldrich) e extraído de vermicomposto (Humus de minhoca); microalga Spirulina (cianobactéria), ácido algínico e ácido poliacrílico de massas molares 2000 e 250000g/mol. Foram realizadas titulações potenciométricas alcalimétricas em diferentes meios iônicos à 25°C com os compostos acima citados. Os dados obtidos foram tratados por linearização (Funções de Gran Modificadas) e regressão não-linear. Os resultados obtidos pelo ácido húmico extraído de vermicomposto (humus de minhoca) e da microalga Spirulina mostraram-se indepentes da força iônica; indicando que o modelo de sítios discretos representa adequadamente os dados experimentais. Para as demais amostras, a estequiometria dos grupos determinados mostrou-se independente do meio iônico, porém os valores de pKa foram bastante afetados, devido à forte influência das interações eletrostáticas decorrentes da acumulação de cargas sobre as macromoléculas durante as titulações. Comparativamente os resultados obtidos tanto por regressão não linear como pelas Funções de Gran modificadas foram similares. / Acid base properties of some polyeletrolytes and colloidal suspensions were studied to evaluate the suitability of discrete site distribution model to fit potentiometric data for determination and characterization of ionizable groups presents in these materials. The polyelectrolytes studied were: commercial humic acid from Aldrich, humic acid isolated from vermicompost, mixed species of microalgae Spirulina, alginic acid and polyacrylic acid of molar masses 2000 and 250000 g/mol. Potentiometric titrations were performed in different ionic media to evaluate the effect of eletrostatic interactions on the titration data. Titrations were perfomed at 25°C, and the data were treated bya linear method based on Modified Gran Functions, as well as by a multiparametric Non-Linear Regression method. The results obtained for the vermicompost humic acid and Spirulina were independent of the ionic strength, suggesting that the chemical heterogeneity plays the major role in the acid base properties of these materials. Thus, the discrete site distribution model is well suited to characterize these materials. For the other polyelectrolytes studied, the influence of eletrostatic interactions was noticed. The discrete site distribution model was able to determine the total stoichiometry of the ionizable groups, but the ionization constants and the distribution of site concentration were dependent on the ionic strength and molar mass of these polyelectrolyte.