<p>Nicaragua is a country in which the toxic metal contamination of freshwater resources has become an increasingly important problem in certain regions posing a threat to the environment as well as to human health. Among the metals found in the waters of Nicaragua, arsenic is one of the most problematic since its long time consumption is connected to serious health problems such as cancer and neurological disorders. The arsenic contamination of water recourses in Nicaragua is mostly attributable natural factors, even though anthropogenic activities including gold mining may be a contributing factor.</p><p>In this work the biopolymer Chitosan was studied as a potential adsorption material for the removal of arsenic from aqueous solutions for water treatment design purposes.</p><p>The Chitosan used in this study was extracted from shrimp shells with an overall yield of 40% and a deacetylation grade of 59%. The maximum adsorption capacity was determined to 20.9 mg As/g at a controlled pH of 5.5 using the Langmuir isotherm. The adsorption was found to be strongly pH dependant with a fourfold increase in adsorption capacity when pH was well under the pKa of Chitosan. The pH dependence indicates that ionic exchange was the most important mechanism. No difference in adsorption capacity with respect to the initial pH of the solution was detected in the pH range 3-7. This was attributed to the ability of Chitosan to act as a weak base in water solutions.</p><p>The arsenic was desorbed from Chitosan using NaOH, (NH4) 2SO 4 and NaCl, with a 1M NaOH solution being the most efficient displaying a concentration ratio of 1.08. The NaOH and (NH4) 2SO 4 solutions displayed a steep desorption curvature with a large fraction of the arsenic being easily desorbed. The arsenic was, however, not completely desorbed from the Chitosan implying that the adsorption capacity would decrease for the coming cycles. Being a biopolymer the Chitosan is quite easily degraded in acid and alkali solutions, which might be a limiting step for the process applicability.</p>

The Big South Fork National River and Recreation Area encompasses more than 50,585 hectares (125,000 acres) of the Cumberland Plateau along the border of Tennessee and Kentucky. Highly dissected and steep terrain have made accessibility to much of the park limited, thus little work has been done to investigate the formation of these soils. Seven native soil profiles were selected for chemical and physical analysis representing Pennsylvanian-aged acidic sandstone and shale geology and landforms. The objectives of this study included the characterization of selected native profiles by physical and chemical analysis, as well as classification using US Soil Taxonomy, to determine baseline soil fertility through chemical analysis, to provide fertilizer recommendations for Bicolor Lespedeza (Lespedeza bicolor) to be grown as wildlife food plots. The parent materials and site- specific geology, including the Pennington Formation, were compared to the profiles in order to establish any relationships that might exist. The methods of chemical analysis included: total carbon analysis, cation exchange capacity, percent base saturation, pH, particle size analysis, KCl total acidity, total elemental analysis and Mehlich I extraction. From the data, soils examined from an upland summit have the lowest Mehlich I extractable phosphorus (M1P) ranging from 0.8-3.14 mg kg-1, and this soil was classified as a Typic Hapludult. Soils examined on backslopes and sideslopes had M1P values ranging from 0.3-11.53 mg kg-1 and these soils were classified as either Lithic Dystrudepts or Typic Dystrudepts. The footslope soils examined have M1P values ranging from 1.95-19.79 mg kg-1 and were classified as Typic Hapludults. Floodplain soils had M1P values from 7.69-56.85 mg kg-1 and were classified as Fluventic Dystrudepts. Landscape position and parent material play major roles in the formation of soils, and their degree of weathering controls the amount of plant available nutrients. Using geologic and topographic maps for comparison, it was concluded that the development of these soils was directly related to the underlying geology and the surrounding topography throughout various landscapes. This information can be used as a guide to aid in predicting the chemical and physical properties of native soils on the Cumberland Plateau.

In order to properly evaluate the ecological and human health risks of ZnO Manufactured nanomaterials (MNMs) released to the environment, it is critical to understand the likely transformation products in the wastewater treatment process and in soils receiving biosolids. To address this critical knowledge gap, we examined the transformation reactions of 30 nm ZnO MNMs in single component and multi-component systems, with phosphate and natural organic matter (NOM). We also assessed the influence of nano ZnO transformation on the bioavailability, and toxicity of ZnO transformation products to Triticum aestivum. The data revealed that ZnO MNMs react with phosphate at concentrations expected in wastewater and transform into two distinct morphological/structural phases. A micron scale crystalline zinc phosphate phase (hopeite), and a nano-sized phase that likely consists of a ZnO core with a Zn3(PO4)2 rich shell. Presence of NOM reduces particle aggregation and enhances stability, regardless of the sequence of ligands addition in the aging scenarios. The presence of phosphate and NOM also altered the bioavailability and reduced the toxicity of the ZnO MNMs to Triticum aestivum.

Conventional waste water treatment processes are not completely effective in removing highly stable organic compounds. Photocatalytic degradation on titanium dioxide is a possible alternative technique for many classes of these compounds. Several studies have been done by other researchers to study mechanisms of photocatalytic degradation, which occurs either through direct oxidation by holes or via indirect oxidation by radical messengers. Titanium dioxide can oxidize substrates directly through hole oxidation mechanisms or indirectly through free radical mechanisms. Substrates must bind onto the catalyst surface to undergo direct oxidation by holes. Thermogravimetric analysis (TGA) was performed on four different classes of compounds; iodinated contrast agents (iohexol and diatrizoate), polycyclic aromatic hydrocarbons (perylene and pyrene), the antibacterial agent triclosan and the pesticide atrazine, to investigate which of the compounds are adsorbed on the surface of titanium dioxide to undergo direct oxidation through electron holes. Differential scanning calorimetry (DSC) was conducted on triclosan and atrazine to determine if the desorption reaction is endothermic or exothermic. Powder X-ray diffraction was performed on all four classes of compounds to observe diffraction pattern of these compounds.

The extensive agricultural usage of organohalogenated pesticides has raised many concerns about their potential hazards especially in the soil environment. Environmental metabolomics is an emerging field that investigates the changes in the metabolic profile of native organisms in their environment due to the presence of an environmental stressor. Research presented here explores the potential of Nuclear Magnetic Resonance (NMR)-based metabolomics to examine the sub-lethal exposure of the earthworm, Eisenia fetida to sub-lethal concentrations of organohalogenated pesticides. Various one-dimensional (1-D) and two dimensional (2-D) NMR techniques were compared in a contact filter paper test earthworm metabolomic study using endosulfan, a prevalent pesticide in the environment. The results determined that both the 1H Presaturation Utilizing Gradients and Echos (PURGE) and the 1H-13C Heteronuclear Single Quantum Coherence (HSQC) NMR techniques were most effective in discriminating and identifying significant metabolites in earthworms due to contaminant exposure. These two NMR techniques were further explored in another metabolomic study using various sub-lethal concentrations of endosulfan and an organofluorine pesticide, trifluralin to E. fetida. Principal component analysis (PCA) tests showed increasing separation between the exposed and unexposed earthworms as the concentrations for both contaminants increased. A neurotoxic mode of action (MOA) for endosulfan and a non-polar narcotic MOA for trifluralin were delineated as many significant metabolites, arising from exposure, were identified. The earthworm tissue extract is commonly used as the biological medium for metabolomic studies. However, many overlapping resonances are apparent in an earthworm tissue extract NMR spectrum due to the abundance of metabolites present. To mitigate this spectral overlap, the earthworm’s coelomic fluid (CF) was tested as a complementary biological medium to the tissue extract in an endosulfan exposure metabolomic study to identify additional metabolites of stress. Compared to tests on the tissue extract, a plethora of different metabolites were identified in the earthworm CF using 1-D PURGE and 2-D HSQC NMR techniques. In addition to the neurotoxic MOA identified previously, an apoptotic MOA was also postulated due to endosulfan exposure. This thesis also explored the application of 1-D and 2-D NMR techniques in a soil metabolomic study to understand the exposure of E. fetida to sub-lethal concentrations of endosulfan and its main degradation product, endosulfan sulfate. The earthworm’s CF and tissue extract were both analyzed to maximize the significant metabolites identified due to contaminant exposure. The PCA results identified similar toxicity for both organochlorine contaminants as the same separation, between exposed to the unexposed earthworms, were detected at various concentrations. Both neurotoxic and apopotic MOAs were observed as identical fluctuations of significant metabolites were found. This research demonstrates the potential of NMR-based metabolomics as a powerful environmental monitoring tool to understand sub-lethal organohalogenated pesticide exposure in soil using earthworms as living probes.

CAPES / As cianobactérias se proliferam rapidamente em ambientes eutrofizados e podem ser capazes de sintetizar toxinas que inviabilizam a utilização dos recursos hídricos. A espécie Microcystis aeruginosa apresenta ampla distribuição, além de ser potencial produtora de hepatotoxinas denominadas microcistinas. O risco à saúde humana destas substâncias faz com que os métodos para controle destes microrganismos na água adquiram fundamental importância. De forma a verificar possíveis efeitos inibitórios de compostos fitoquímicos produzidos por macrófitas aquáticas sobre o crescimento e a produção de microcistinas da cianobactéria Microcystis aeruginosa, o presente estudo utilizou extratos hidroalcoólicos de sete espécies de macrófitas aquáticas (Eichhornia azurea, Eleocharis cf. acutangula, Ludwigia cf. peruviana, Myriophyllum cf. aquaticum, Pontederia cordata, Sagittaria montevidensis e Typha domingensis). O meio de cultura ASM-1 foi otimizado em relação ao pH, nitrogênio, fósforo e ferro através de planejamento fatorial. Para o preparo dos extratos, as sete espécies de macrófitas aquáticas foram coletadas, processadas e submetidas ao processo de extração com solução hidroetanólica 80% (v/v). Os extratos obtidos foram liofilizados e aplicados em concentrações conhecidas aos cultivos de M. aeruginosa, em meio ASM-1 otimizado. O monitoramento da concentração celular foi realizado a cada 48 h por 10 dias. As diferenças estatísticas foram avaliadas através do método estatístico ANOVA repeated. A determinação da concentração de microcistina-LR foi realizada nas culturas contendo a concentração de extrato de maior efeito inibitório. Para a verificação de efeitos bacteriostáticos e bactericidas, ao final do período testado, os cultivos foram reinoculados em tubos de ensaio contendo apenas o meio de cultura estéril. Os extratos foram avaliados quanto à presença de metabólitos secundários e à toxicidade aguda sobre Daphnia magna. Os experimentos apresentaram valores de crescimento elevados no meio que continha maiores concentrações de P e Fe. Os extratos inibiram significativamente o crescimento da cepa quando foram aplicados na concentração de 500 mg.L-1, com exceção do extrato obtido a partir de S. montevidensis em que o efeito inibitório sobre as células foi o menor observado. O extrato com maior efeito inibitório foi obtido de partes aéreas de M. cf. aquaticum pois a taxa de inibição foi de 99,1% na concentração de 500 mg.L-1. As análises de microcistina evidenciaram que para o extrato de E. cf. acutangula a redução do crescimento foi acompanhada de aumento na produção de microcistina-LR de 216 para 610 ppb. Nos testes com o extrato de S. montevidensis a concentração de toxina sofreu pouca alteração, aumentando de 216 para 222 ppb. Efeitos bactericidas foram verificados para a exposição aos extratos de E. cf. acutangula, L. cf. peruviana e M. cf. aquaticum, uma vez que após reinoculadas não foram verificados crescimentos celulares. Para os extratos de E. azurea, P. cordata e T. domingensis não foram observados efeitos tóxicos, por outro lado, a maior toxicidade ocorreu para S. montevidensis, pois 100% dos organismos apresentaram imobilidade na concentração de 50 mg.L-1. Considerando os dados de inibição e de toxicidade foi possível constatar que o extrato obtido de L. cf. peruviana apresentou maiores vantagens em sua aplicação. Os resultados obtidos indicam a possibilidade futura da aplicação de extratos para a remediação de florações e mostram, também, a necessidade de investigações fitoquímicas e toxicológicas mais detalhadas no sentido de identificar as substâncias ativas no controle de florações, de forma a potencializar a ação destas e minimizar seus efeitos tóxicos. / Cyanobacteria proliferate rapidly in eutrophic environments and may be able to synthesize toxins that block water resources use. The cyanobacterium Microcystis aeruginosa is widely distributed, being a potential producer of hepatotoxins called microcystins. The risks to human health of these substances demands methods to control these microorganisms in water. In order to investigate possible inhibitory effects of phytochemical compounds produced by aquatic macrophytes on the growth and microcystin production of Microcystis aeruginosa, the present study used aquatic macrophytes hydroalcoholic extracts of seven species (Eichhornia azurea, Eleocharis cf. Acutangula, Ludwigia cf. peruviana, yriophyllum cf. aquaticum, Pontederia cordata, Sagittaria montevidensis and Typha domingensis). The culture medium ASM-1 was optimized with respect to pH, nitrogen, phosphorus and iron through a factorial design. For extracts preparation, the seven species of aquatic macrophytes were collected, processed and submitted to extraction process solution ethanol 80% (v/v). The extracts were lyophilized and applied in known concentrations to cultures of M. aeruginosa, in optimized ASM-1 medium. Cell concentration was determined every 48 h for 10 days. Statistical differences were evaluated using ANOVA repeated. The microcystinLR concentration was determined in cultures containing greater inhibitory effect extract concentration. Evaluation of bacteriostatic and bactericidal effects at the end of tested period, the cultures were reinoculated into test tubes containing only sterile culture medium. The extracts were evaluated for the presence of secondary metabolites and acute toxicity on Daphnia magna. The experiments showed high growth rates in medium containing higher concentrations of P and Fe. Hydroalcoholic extracts inhibited the growth of Microcystis aeruginosa strain, more effective when applied at a concentration of 500 mg L-1, except for tests performed with S. montevidensis in that the mean inhibitory effect on the cells was the lowest observed. The extract with the highest inhibitory effect was obtained from aerial parts of M. cf. aquaticum in which the inhibition rate was 99.1%. The analyzes showed that microcystin for the extract of E. cf. acutangula the greatest cellular inhibition was accompanied by an increase in microcystin-LR production from 216 to 610 ppb. In tests with S. montevidensis extract the concentration of toxin was few changed, increasing from 216 to 222 ppb. Bactericidal effects were observed for exposure to extracts of E. cf. acutangula, L. cf. peruviana and M. cf. aquaticum. For extracts of E. azurea, P. cordata and T. domingensis toxic effects were not observed. The major toxicity was observed for S. montevidensis, in which 100% of organisms presented immobility in concentration of 50 mg.L-1. Considering inhibition and toxicity data was found that L cf. peruviana extract showed more advantages on its application. The results indicate the possibility of future application of extracts for blooms remediation and also show the need for detailed toxicological and phytochemical investigations in order to identify the active compounds in blooms control and minimize their toxic effects.

A key reaction in the troposphere involves the oxidation of biogenic and anthropogenic alkenes with ozone, which contributes to local photochemical smog. It is generally accepted that this reaction proceeds via a reactive intermediate often called the Criegee intermediate (CI). This reaction is known to produce a plethora of oxidised organic compounds, which contribute to ozone formation and secondary organic aerosol production, two of the main characteristics of a polluted atmosphere. Furthermore, epidemiological studies have shown a close correlation between exposure to ambient organic aerosol and adverse human health effects. The toxicological mechanisms leading to this observation are still poorly characterised, although studies suggest that reactive oxygen species present in organic aerosol are a major contributor. Reactive oxygen species and reactive intermediates represent a large uncertainty in tropospheric chemistry, and pose an analytical challenge due to their high reactivity and typically low concentrations. This emphasises the need for the development of new methods to characterise the chemistry of these species. In this thesis, several novel laboratory based techniques have been developed in order to characterise and quantify reactive intermediates and reactive oxygen species. New methods to facilitate the detection of CIs in both the gas and particle phase are presented. Spin trap molecules are used to scavenge CIs to form stable 1:1 adducts which are subsequently detected and quantified using mass spectrometry. The chemistry of CIs with spin traps is extensively investigated. The unique capability of this technique to simultaneously characterise multiple CIs generated from a variety of atmospherically relevant organic precursors in the gas phase is demonstrated. This technique was further developed to facilitate the detection of CIs in secondary organic aerosol, representing the development of a method capable of characterising low volatility CIs and other reactive intermediates in the condensed phase. Furthermore, two new chemical fluorescence assays have been developed to quantify both organic radicals and reactive oxygen species in organic aerosol. A novel profluorescent spin trap assay was applied to quantify radical concentrations in organic aerosol. A series of experiments were then devised to investigate the lifetime of organic radicals in secondary organic aerosol. A second assay, based on physiologically relevant ascorbic acid chemistry, was also developed to measure the concentrations of toxicologically relevant reactive oxygen species in secondary organic aerosol. The quantitative capability of this assay was extensively characterised. The assay was incorporated into a prototype instrument capable of measuring particle-bound reactive oxygen species on-line, and the assays’ sensitivity to secondary organic aerosol was demonstrated.

Made available in DSpace on 2014-06-11T19:35:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-29Bitstream added on 2014-06-13T20:45:58Z : No. of bitstreams: 1 mendonca_agr_dr_araiq.pdf: 5684091 bytes, checksum: 9b3a80cd7c8f6c2fa5faeeb3ca0ed1b9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Turfas apresentam em média 80% de compostos orgânicos em sua composição. A variedade e elevada quantidade de grupos funcionais, principalmente oxigenados, nitrogenados e sulfurados, possibilitam elevada capacidade de interação com espécies metálicas, formando compostos de diferentes estabilidades. Além da importante função ambiental, tais como participação em processos de acúmulo, transporte e disponibilidade de espécies metálicas no ambiente, as turfas possuem várias aplicações comerciais, dentre elas, destaca-se a remediação de áreas contaminadas e utilização na agricultura e horticultura, onde são empregadas como adubo natural. Quanto à aplicação de turfas no setor agrícola, há uma crescente procura pela adubação orgânica. Neste caso, existem várias questões em aberto como, por exemplo, a necessidade de entendimento da disponibilização ou não de nutrientes pela matéria orgânica, quando enriquecida com macro e micro nutrientes essenciais. Neste trabalho, foram estudadas as interações de espécies metálicas (Cu, Mg, Ca, Zn, Mn e Fe) com turfas e substâncias húmicas extraídas dessas matrizes. Foram coletadas amostras de turfas no Distrito de Taquaral-SP e no município de São Simão-SP. As amostras foram caracterizadas com diferentes técnicas, tais como: granulometria, infra-vermelho, análise elementar, RMN 13 C CP- MAS / RMN DOSY e HPSEC. Foram determinadas as capacidades de complexação e constantes de troca entre as substâncias húmicas extraídas das amostras de turfas e espécies metálicas. Experimentos em casa de vegetação (UNESP – Jaboticabal) foram feitos para avaliar a influência das diferentes amostras e das quantidades de turfas no desenvolvimento e estado nutricional das plantas testadas (milho e rabanete). Os resultados deste trabalho contribuem no melhor entendimento sobre alguns fatores que influenciam... / Peats of natural origin have on average 80% of organic compounds in its composition. The variety and high quantity of functional groups, mainly oxygen, nitrogen and sulfur, enable high capacity for interaction with metal species, forming compounds of different stability. Beyond the environmental importance, such as participation in processes of accumulation, transportation and disposal of metal species in the environment, peats have various commercial applications, among which stands out the remediation of contaminated areas and the use in agriculture and horticulture, where they are used as natural fertilizer. As for the application of peats in the agricultural sector, there is a growing demand for organic fertilizer. In this case, there are several open issues such as the need for understanding the availability or not of nutrients in organic matter, when enriched with macro and micro essential nutrients. In this work, were have studied the interactions of metal species (Cu, Mg, Ca, Zn, Mn and Fe) with peats and humic substances. Peat samples were collected in the Taquaral-SP district and the São Simão-SP city. The samples were characterized with different techniques, such as size, infrared spectroscopy, elemental analysis, 13 C NMR CP-MAS / NMR DOSY and HPSEC. The capacity of complexation and exchange constants between humic substances extracted from peat samples and metal species were determined. Experiments in a greenhouse (UNESP - Jaboticabal) were carried out to evaluate the influence of the different samples and the quantities of peat in the development and status of tested plants (corn and radish). The results of this study contribute for a better understanding of factors that influence the interactions between metal species and soil organic matter, for improvements in agricultural practices, aiming at better yields and less environmental impacts

The Florida Everglades is a massive and highly managed subtropical wetland ecosystem, strongly influenced by anthropogenic control of freshwater distribution and highly susceptible to a changing climate, including rising sea-level and changes in temperature and rainfall. Shifting hydrologic regimes impact ecosystem function and biogeochemistry, which in turn control the sources, fate, and transport of organic matter. As a master environmental variable, it is essential to understand how organic matter dynamics will respond to changes in the balance between freshwater and saltwater associated with landscape-scale Everglades restoration efforts and climate change. The research comprising this dissertation improves current understanding of the linkages between organic matter and hydrology in the Everglades across a broad range of temporal and spatial scales. A range of research tools, including stable molecular biomarkers, water quality sensors, data synthesis and multivariate statistics were utilized. Biomarkers were used to track particulate organic matter mobilization in response to experimentally manipulated flows and provided initial evidence that sheet flow restoration can re-engineer landscape microtopography, influencing both ecosystem structure and organic matter inputs to Everglades National Park (ENP). Short-term and long-term temporal studies indicated the quantity and quality of dissolved organic carbon responds to changes in freshwater flow to marshes and mangrove forests in ENP, and that spatial patterns and trends are driven by a complex mixture of managed and natural surface water inputs (i.e., rainfall and water management inflows) as well as groundwater discharge. Application of climate scenario forecasting to relationships established between organic matter and hydrologic drivers predicted reductions in dissolved organic carbon export from ENP and changes in organic matter molecular composition. Furthermore, high-frequency measurements showed hydrologic connectivity of freshwater and estuarine organic matter pools at sub-monthly time-scales. In summary, the work presented here clearly indicates strong yet spatiotemporally complex relationships between changes in water and the sources and transport of organic carbon through the Everglades.

Orientador: Altair Benedito Moreira / Coorientador: Eduardo Alves de Almeida / Banca: Juliana Delatim Simonato Rocha / Banca: Gustavo Orlando Bonilla Rodriguez / Resumo: O fipronil, inseticida pertencente ao grupo dos fenilpirazóis é amplamente utilizado no cultivo da cana-de-açúcar na região noroeste do estado de São Paulo, gerando preocupações no âmbito da contaminação ambiental que este e seus produtos de degradação podem causar, afetando a qualidade da água, do solo, do sedimento, e até mesmo organismos não alvo presentes no ambiente em questão. Foram feitos experimentos expondo girinos de Eupemphix nattereri a concentrações conhecidas de fipronil, fipronil sulfona e fipronil sulfeto utilizando recipientes contendo 200 g de solo e 1,0 L de água, de maneira a simular o ambiente natural em que os referidos anfíbios vivem. Foram adicionados 8 girinos por aquário, durante um período de 7 dias, para avaliar o sistema de defesa antioxidante dos organismos, analisando enzimas antioxidantes e a peroxidação lipídica. Após a exposição, foram feitas a extração e quantificação dos analitos na água e no sedimento utilizados por meio da técnica de cromatografia em fase gasosa acoplada a espectrometria de massas (GC-MS). As concentrações utilizadas nos experimentos foram 35,0; 120,0 e 180,0 μg kg de solo-1, concentrações essas encontradas em solos com plantação de cana-de-açúcar em estudos já realizados. Foi possível confirmar a preferência do fipronil e seus metabólitos por matrizes lipofílicas, já que os contaminantes se depositaram principalmente no sedimento. Pôde-se também observar que o fipronil é passível de provocar estresse oxidativo nos girinos, uma vez que foram observadas alterações na atividade enzimática da catalase e houve peroxidação lipídica após os experimentos, sob as três concentrações estudadas. O produto de degradação gerado a partir da oxidação do fipronil, o fipronil sulfona, também provoca estresse oxidativo nos organismos, pelo fato de ter aumentado o nível da peroxidação lipídica em duas... / Abstract: Fipronil, a phenylpyrazole insecticide, is widely used in the cultivation of sugar cane in the northwest of São Paulo, raising concerns on environmental contamination that it and its metabolites can cause, affecting the quality of water, soil, sediments, and even non-target organisms in the environment in question. Experiments were carried out exposing tadpoles Eupemphix nattereri to known concentrations of fipronil, fipronil sulfone and fipronil sulfide using vials containing 200 g of soil and 1.0 L of water, to simulate the natural environment of amphibians. Then were added 8 tadpoles, for a period of 7 days, to evaluated the antioxidant defense system bodies, analyzing antioxidant enzymes and lipid peroxidation. After exposure, were made the extraction and quantification of analytes in the water and the sediment using a gas phase chromatography technique coupled with mass spectrometry (GC-MS). The concentrations used in the experiments were 35,0; 120,0 and 180,0 μg kg-1 soil, these concentrations found in soils with sugar cane plantation in previous studies. It was possible to confirm preferably fipronil and metabolites by lipophilic matrix since the contaminants were deposited primarily in the sediment. It might also observe that fipronil is likely to cause oxidative stress in tadpoles, as changes were observed in the catalase enzyme activity and lipid peroxidation after the experiments, under the three concentrations studied. The degradation product generated from the oxidation of fipronil, fipronil sulfone, also causes oxidative stress in the body, because it has increased the level of lipid peroxidation in two of three concentrations studied, despite no change in the activity of antioxidant enzymes. Moreover, fipronil sulfide product generated by reduction, was the least aggressive to the tadpoles studied, since only in its highest concentration was increased activity of the antioxidant enzymes... / Mestre