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Advisor(s)
Abstract(s)
Os hidrocarbonetos aromáticos policíclicos (HAPs) são formados durante a combustão incompleta da matéria orgânica. Estão presentes em todo o lado e são sempre encontrados como uma mistura de compostos individuais, apresentando uma persistência muito considerável no meio ambiente, com elevada tendência para se bioacumularem, pois não se degradam facilmente. Dentre os muitos HAPs existentes, que podem ser encontrados em plantas terrestres e aquáticas, em solos e sedimentos, na água e na atmosfera, 16 são considerados poluentes prioritários por serem mais tóxicos, mutagénicos e carcinogénicos que os restantes merecendo especial atenção devido aos riscos que podem oferecer à saúde humana e de outros animais. Com este trabalho pretende-se proceder à pesquisa bibliográfica da presença de HAPs em solos queimados e analisar amostras de solo recolhidas em diferentes locais de Portugal e Espanha e em diferentes períodos. Para determinar o conteúdo de 17 HAPs (16 deles prioritários), foram analisadas amostras de solo de locais sujeitos a incêndios florestais. A investigação incidiu em três áreas de estudo distintas na Península Ibérica afetadas por estas catástrofes. Uma em Espanha localizada na Serra ou Montes de Forgoselo, outra na fronteira Portugal-Espanha localizada na Portela do Homem e outra em Bragança, a norte de Portugal. Para a preparação das amostras, foi utilizado o método de extração QuEChERS, um método alternativo a outros tradicionais menos eficientes, por ser rápido, fácil, barato, eficaz, robusto e seguro, além de apresentar altas taxas de recuperação. Para analisar a presença de HAPs, foi utilizada Cromatografia Líquida de Alta Eficiência (HPLC), acoplada a um Detetor de Fotodiodos e um Detetor de Fluorescência (HPLC-PAD- FLD) por apresentar alta seletividade e sensibilidade, demonstrando também grande estabilidade, linearidade, limite de deteção, limite de quantificação, recuperação, reprodutibilidade e precisão. Os resultados obtidos demonstram que a concentração de HAPs em estudo nos solos que sofreram combustão, ou por ela influenciados, é superior à concentração de HAPs em solos que não sofreram combustão. Os resultados sugerem também que os compostos com maior peso molecular são os que apresentam maior dificuldade de degradação no meio ambiente, pois são os que persistem em maior quantidade após algum tempo. Parâmetros químicos como pH, matéria orgânica ou teor em água podem, de igual modo, influenciar a concentração de HAPs retida num determinado local.
Polycyclic aromatic hydrocarbons (PAHs) are formed during incomplete combustion of organic matter. They are present everywhere and are always found as a mixture of individual compounds, showing a very considerable persistence in the environment, with a high tendency to bioaccumulate, because they are not easily degraded. Among the many existing PAHs, that can be found in terrestrial and aquatic plants, in soils and sediments, in water and in the atmosphere, 16 are considered as priorities pollutants because they are more toxic, mutagenic, and carcinogenic than the others deserving special attention due to the risks that they can offer to human and other animal health. The goal of this work is to carry out bibliographical research on the presence of PAHs in burnt soils and analyse soil samples collected in different places in Portugal and Spain and in different periods. To determine the content of 17 PAHs (16 of which are the priority ones), soil samples from places subject to forest fires were analysed. The research focused on three different study areas in the Iberian Peninsula, for being an area very affected by these catastrophes. One in Spain located in Serra or Montes do Forgoselo, another on the Portugal-Spain border located in Portela do Homem and another in Bragança, north of Portugal. To prepare the samples, the QuEChERS extraction method was used, an alternative method to other less efficient traditional ones, because it is fast, easy, cheap, effective, robust and safe, in addition to leading to high recovery rates. To analyse the presence of PAHs, high performance liquid chromatography (HPLC) was used, coupled to a diode detector and a fluorescence detector (HPLC-PAD-FLD) which is very efficient and presents a high selectivity and sensitivity, also demonstrating great stability, linearity, limit of detection, limit of quantification, very, reproducibility and precision. The results obtained demonstrate that the concentration of PAHs under study in soils that suffered combustion, or influenced by it, is higher than the concentration of PAHs in soils that haven´t suffered combustion. The results also suggest that the compounds with higher molecular weight are the ones that have more difficulty in degrading in the environment since they are the ones that persist in greater quantities after some time. Chemical parameters such as pH, organic matter or % moisture can similarly influence the concentration of PAHs retained in a certain place.
Polycyclic aromatic hydrocarbons (PAHs) are formed during incomplete combustion of organic matter. They are present everywhere and are always found as a mixture of individual compounds, showing a very considerable persistence in the environment, with a high tendency to bioaccumulate, because they are not easily degraded. Among the many existing PAHs, that can be found in terrestrial and aquatic plants, in soils and sediments, in water and in the atmosphere, 16 are considered as priorities pollutants because they are more toxic, mutagenic, and carcinogenic than the others deserving special attention due to the risks that they can offer to human and other animal health. The goal of this work is to carry out bibliographical research on the presence of PAHs in burnt soils and analyse soil samples collected in different places in Portugal and Spain and in different periods. To determine the content of 17 PAHs (16 of which are the priority ones), soil samples from places subject to forest fires were analysed. The research focused on three different study areas in the Iberian Peninsula, for being an area very affected by these catastrophes. One in Spain located in Serra or Montes do Forgoselo, another on the Portugal-Spain border located in Portela do Homem and another in Bragança, north of Portugal. To prepare the samples, the QuEChERS extraction method was used, an alternative method to other less efficient traditional ones, because it is fast, easy, cheap, effective, robust and safe, in addition to leading to high recovery rates. To analyse the presence of PAHs, high performance liquid chromatography (HPLC) was used, coupled to a diode detector and a fluorescence detector (HPLC-PAD-FLD) which is very efficient and presents a high selectivity and sensitivity, also demonstrating great stability, linearity, limit of detection, limit of quantification, very, reproducibility and precision. The results obtained demonstrate that the concentration of PAHs under study in soils that suffered combustion, or influenced by it, is higher than the concentration of PAHs in soils that haven´t suffered combustion. The results also suggest that the compounds with higher molecular weight are the ones that have more difficulty in degrading in the environment since they are the ones that persist in greater quantities after some time. Chemical parameters such as pH, organic matter or % moisture can similarly influence the concentration of PAHs retained in a certain place.
Description
Keywords
HAPs Incêndios florestais Solo QuEChERS HPLC-PAD-FLD Forest fires Soil