Orientador: Anne Hélène Fostier / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-22T11:06:51Z (GMT). No. of bitstreams: 1 MelendezPerez_JoseJavier_M.pdf: 2237869 bytes, checksum: 3710e09e3870c2884c380a0ae8589f27 (MD5) Previous issue date: 2013 / Resumo: O presente trabalho buscou avaliar o impacto da queima de florestas na região Amazônica sobre as emissões de Hg devidas, tanto à queima de biomassa, quanto do solo durante a queimada. Grande parte dos dados necessários foi adquirida a partir de um experimento de queimada programada, numa parcela de floresta de 2,25 ha localizada na estação experimental da EMBRAPA, em Rio Branco (Acre), que foi realizada em setembro de 2011. O fator de emissão de Hg, definido aqui como a massa de Hg emitida por área de floresta, foi calculado pela diferença no estoque de Hg antes e depois da queima obtendo um valor de aproximadamente 4 g Hg ha. Para determinar o fator de emissão foram coletadas e analisadas amostras de solos e vegetação. A concentração de Hg nas amostras coletadas foi determinada usando um método de análise direto por decomposição térmica da amostra e detecção por absorção atômica, que evita a maioria dos processos típicos de pré-tratamento da amostra como digestões acidas, redução do Hg(II) e etapas de separação líquido-gás. Este trabalho integra-se a um amplo programa de estudos destinados a quantificar as principais emissões e parâmetros de consumo de biomassa em queimas de floresta amazônica desenvolvidos por pesquisadores do Instituto Nacional de Pesquisas Espaciais (INPE) e da Universidade Estadual Paulista (UNESP). Estes realizaram um inventário florístico no sitio de estudo e forneceram os dados de biomassa e de eficiência de combustão necessários para os cálculos do fator de emissão. Também foi realizado um estudo de especiação de Hg no solo da floresta, onde foi encontrando que a espécie predominante é o Hg(II). Foram avaliados alguns indicadores da severidade do fogo durante a queima da floresta, tais como o registro de temperatura do solo e a relação Ca/C no solo superficial da floresta. / Abstract: The present work aims to assess the impact of forest fires in the Amazonian region on mercury emissions due to biomass and soil burning during the fire. A large part of the data was obtained from an experimental burning of a 2.25 ha forest plot, located in the EMBRAPA experimental field station near Rio Branco (Acre), carried out in September 2011. The mercury emission factor, defined here as the mass of mercury emitted per area of forest, was calculated by the difference of mercury burden before and after fire and it was found a value of about 4 g ha. Before burning experiment, samples of vegetation (leaves, wood and litterfall) and soil (up to 5 cm deep) were collected. The mercury concentration of the samples was determined by using a method of direct mercury analysis based on thermal decomposition of the sample and atomic absorption detection, avoiding most of the typical processes for sample pretreatment such as acidic digestion, Hg(II) reduction and gas-liquid separation steps. This work is part of a large study which aims to quantify the main emission and consumption parameters of Amazonian forest fires which and is conducted by researchers from the Instituto Nacional de Pesquisas Espaciais (INPE) and the Universidade Estadual Paulista (UNESP). They performed a floristic inventory from the experimental plot and provided the biomass and combustion efficiency data necessary for emission factor calculation. A speciation study of mercury was performed in the forest soil, by using a technique of termodessorption coupled with atomic absorption, where it was found that the predominant specie was Hg(ll). Parameters like temperatures recorded with thermocouples in some depths during the forest fire and Ca/C ratio of superficial soil were assessed as indicators of fire severity. / Mestrado / Quimica Analitica / Mestre em Química

Indiana University-Purdue University Indianapolis (IUPUI) / Mercury (Hg) has proven to be a risk to the public, mainly through the consumption of fish. Because of this, many fish consumption advisories have been issued in Indiana. Although much is known about the global cycle of mercury, little is known about how local and regional emission sources of mercury impact local and regional mercury cycling. This study’s objective was to determine the scope of mercury concentration in central Indiana by using a broad grid of soil mercury measurements. Sampling was designed to capture the net retained mercury content in soils, and to determine whether spatial patterns in exist in soil mercury contents that could be related to emission sources of mercury and post-emission transport patterns from wind. Results from this study revealed significant differences in mercury concentrations for soils in central Indiana. The core of the study area, concentrated in the urban area of Indianapolis, exhibited soil mercury contents that were 20 times higher than values in the outskirts of the study area. The spatial pattern resembled a bulls-eye shape centered on Indianapolis, and with comparison to the reported Hg emission from local sources, including a coal-fired power plant, indicates a strong regional deposition signal linked to those emission sources but marked by wind-driven transport to the northeast. This effect of local emission sources resulting in local deposition indicates that limiting mercury emissions will have a net beneficial impact on local environmental quality and human health.