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Made available in DSpace on 2014-06-11T19:35:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-15Bitstream added on 2014-06-13T20:46:01Z : No. of bitstreams: 1 machado_cmd_dr_araiq.pdf: 2114078 bytes, checksum: 61bdf746c73d1b3e6f93ee0822ea2c40 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os compostos nitrogenados reativos e o ozônio desempenham funções importantes na atmosfera, atuando na mobilização de nutrientes, na cadeia oxidativa e neutralização atmosférica. Neste trabalho foram avaliados os comportamentos dos principais compostos de nitrogênio (NH3, NO e NO2) e O3 presentes na atmosfera da região central do Estado de São Paulo. Nessa região, a produção de combustível a partir da cana-de-açúcar é a principal fonte antrópica de gases e partículas para a atmosfera. Enquanto o biocombustível apresenta balanço zero para o ciclo biogeoquímico do carbono (em termos de produção de CO2), o mesmo não acontece com o elemento nitrogênio. Neste caso há aumento da disponibilidade de nitrogênio reativo no ambiente, pois a sua mobilização ocorre pelo uso do biocombustível e principalmente nas etapas de sua produção. O processo se inicia com o plantio da cana-de-açúcar e a aplicação de nitrogênio no solo como fertilizante. O nitrogênio é então emitido para a atmosfera principalmente na forma de NOx e NH3. Esses gases também são emitidos durante a colheita, entre abril e outubro (estação seca), quando a palha da cana-de-açúcar é queimada. A análise dos resultados mostrou claramente uma variabilidade sazonal para NO, NO2 e O3, cujas concentrações na estação seca praticamente dobraram em relação à estação chuvosa (novembro a março). O aumento da concentração de NOx na estação seca foi relacionado à acidez atmosférica e à intensificação da produção de O3 observadas neste período. Já as concentrações médias de NH3 não apresentaram variação significativa comparando as estações seca e chuvosa. Contudo, os resultados indicaram duas fontes diferentes de NH3 para a atmosfera ao longo do ano: 1) queima de biomassa durante a estação seca e, 2) o uso de fertilizantes durante a estação chuvosa... / Reactive nitrogen compounds and ozone play a critical role in the atmosphere, influencing nutrient mobilization, oxidative chain and atmospheric neutralization. During this study, the behaviour of major reactive nitrogen compounds (NH3, NO and NO2) and O3 were evaluated in the atmosphere of the central region of São Paulo State. In this region, the production of fuel from sugar cane is the main anthropogenic emission source of gases and particulate matter to the atmosphere. While biofuels can offer clear environmental advantages in relation to the biogeochemical carbon cycle, this is not true for nitrogen. There is a net gain of active nitrogen to the environment because it is mobilized during biofuel use and especially during of the stages of biofuel production. The process starts at sugar cane plantation where nitrogen is applied to soil as a fertilizer. The nitrogen is then released into the atmosphere principally as NH3 and NOx (NO+NO2). Substantial emissions are released during the harvest, between May and October (dry season), when the crop is burned. The results clearly showed a seasonal trend of NO, NO2 and O3, with dry season mean concentrations almost doubling relative to the rainny season (November to March). The increase of NOx concentration during the dry season was associated with an observed increase in atmospheric acidity and O3 production. NH3, however, showed no significant variation in mean concentration seasonally. Nevertheless, the results indicated two very different NH3 sources into the atmosphere during the year; 1) biomass burning during the dry season and, 2) fertilizer application during the rainny season. The diurnal behaviour of NOx and O3 also showed a positive correlation with sugar cane production activities in the region. Maximum NOx concentrations were recorded during the night in the dry season, when sugar cane is burned. Consequently high O3 concentrations...(Complete abstract click electronic access below)

Orientador: Arnaldo Alves Cardoso / Banca: Bernardino Ribeiro de Fiqueiredo / Banca: Raquel Fernandes Pupo Nogueira / Banca: Lilian Rothschild Franco de Carvalho / Banca: Maria de Fátima Andrade / Resumo: Os compostos nitrogenados reativos e o ozônio desempenham funções importantes na atmosfera, atuando na mobilização de nutrientes, na cadeia oxidativa e neutralização atmosférica. Neste trabalho foram avaliados os comportamentos dos principais compostos de nitrogênio (NH3, NO e NO2) e O3 presentes na atmosfera da região central do Estado de São Paulo. Nessa região, a produção de combustível a partir da cana-de-açúcar é a principal fonte antrópica de gases e partículas para a atmosfera. Enquanto o biocombustível apresenta balanço zero para o ciclo biogeoquímico do carbono (em termos de produção de CO2), o mesmo não acontece com o elemento nitrogênio. Neste caso há aumento da disponibilidade de nitrogênio reativo no ambiente, pois a sua mobilização ocorre pelo uso do biocombustível e principalmente nas etapas de sua produção. O processo se inicia com o plantio da cana-de-açúcar e a aplicação de nitrogênio no solo como fertilizante. O nitrogênio é então emitido para a atmosfera principalmente na forma de NOx e NH3. Esses gases também são emitidos durante a colheita, entre abril e outubro (estação seca), quando a palha da cana-de-açúcar é queimada. A análise dos resultados mostrou claramente uma variabilidade sazonal para NO, NO2 e O3, cujas concentrações na estação seca praticamente dobraram em relação à estação chuvosa (novembro a março). O aumento da concentração de NOx na estação seca foi relacionado à acidez atmosférica e à intensificação da produção de O3 observadas neste período. Já as concentrações médias de NH3 não apresentaram variação significativa comparando as estações seca e chuvosa. Contudo, os resultados indicaram duas fontes diferentes de NH3 para a atmosfera ao longo do ano: 1) queima de biomassa durante a estação seca e, 2) o uso de fertilizantes durante a estação chuvosa...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Reactive nitrogen compounds and ozone play a critical role in the atmosphere, influencing nutrient mobilization, oxidative chain and atmospheric neutralization. During this study, the behaviour of major reactive nitrogen compounds (NH3, NO and NO2) and O3 were evaluated in the atmosphere of the central region of São Paulo State. In this region, the production of fuel from sugar cane is the main anthropogenic emission source of gases and particulate matter to the atmosphere. While biofuels can offer clear environmental advantages in relation to the biogeochemical carbon cycle, this is not true for nitrogen. There is a net gain of active nitrogen to the environment because it is mobilized during biofuel use and especially during of the stages of biofuel production. The process starts at sugar cane plantation where nitrogen is applied to soil as a fertilizer. The nitrogen is then released into the atmosphere principally as NH3 and NOx (NO+NO2). Substantial emissions are released during the harvest, between May and October (dry season), when the crop is burned. The results clearly showed a seasonal trend of NO, NO2 and O3, with dry season mean concentrations almost doubling relative to the rainny season (November to March). The increase of NOx concentration during the dry season was associated with an observed increase in atmospheric acidity and O3 production. NH3, however, showed no significant variation in mean concentration seasonally. Nevertheless, the results indicated two very different NH3 sources into the atmosphere during the year; 1) biomass burning during the dry season and, 2) fertilizer application during the rainny season. The diurnal behaviour of NOx and O3 also showed a positive correlation with sugar cane production activities in the region. Maximum NOx concentrations were recorded during the night in the dry season, when sugar cane is burned. Consequently high O3 concentrations...(Complete abstract click electronic access below) / Doutor

INTRODUCTION: Chemical exposures to US pregnant women have been shown to have adverse health impacts on both mother and fetus. A prior paper revealed that US pregnant women in 2003-2004 had widespread exposure to multiple chemicals. The goal of this research is to examine how environmental chemical exposures to US pregnant women have changed from 2003 to 2010 and to look further at the extent of simultaneous exposure to multiple chemicals in US pregnant women using biomonitoring data available through NHANES (the National Health and Nutritional Examination Survey). METHODS: Using available NHANES data from the following cycles (2003-2004, 2005-2006, 2007-2008, 2009-2010), we analyzed how environmental chemical exposures changed over time. Covariates were used and data was weighted to reflect the population of pregnant US women. Each cycle was then compared to the 2003-2004 cycle in order to assess how exposures have changed over time. We then looked at the data in an entirely different fashion. We examined the total number of chemicals detected in a given pregnant woman by chemical group. Finally, we looked at the total number of detects across various chemical groups and used the Fisher Exact Test to study how the distribution of detections changed in 2009-2010 compared to 2003-2004. RESULTS: While at least one-third of the chemicals analyzed showed one cycle that differed, exposure rates of individual chemicals were generally not increasing from 2003-2010. Median number of detections over chemical groups also did not show much difference over time. However, analysis of the change in frequency distributions revealed that, for some chemical groups, the frequency of detects in US pregnant woman significantly increased in 2010 compared to 2003. CONCLUSIONS: Widespread chemical exposures were seen in US pregnant women from 2003 through 2010. The number of chemical analytes detected in US pregnant women’s bodies is rising. Many chemicals studied had similar mechanisms of action and/or similar adverse health outcomes upon exposure which is known to result in a cumulative health effect. This research suggests that we need to focus not only on exposure rates of individual chemicals but also on the overall number of chemicals detected when assessing the overall picture of environmental chemical exposures to pregnant women in the US.

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