979 resultados para Air Pollutants, Occupational Hazardous Substances


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Diplopods feed organic matter in decomposition; however, some environmental factors can promote changes in tissues of these animals. Sewage sludge has been applied for recuperation of physical structure of degraded soil. This work analyzed the influence of the sludge from a city of So Paulo in the midgut of the diplopod Rhinocricus padbergi. After the exposition to sludge, the midgut was prepared for histological and ultra-structural analyses. After 1 week of exposition, there were various glycoprotein globules in the fat body, which appeared, ultrastructurally, little electron dense. In the animals exposed for 2 weeks, there was an intensive renovation of the epithelium with the invasion of regenerative cells, which was observed in the histological and ultra-structural analyses. These data showed that the sludge present various substances that were very hazardous for these animals; more studies were necessary before the application of this in agriculture.

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An experimental investigation of air enrichment in a combustion chamber designed to incinerate aqueous residues is presented. Diesel fuel and liquefied petroleum gas (LPG) were used independently as fuels. An increase of 85% in the incineration capacity was obtained with nearly 50% O-2 in the oxidant gas, in comparison to incineration with air only. The incineration capacity continues increasing for enrichment levels above 50% O-2 , although at a lower pace. For complete oxy-flame combustion (100% O-2 ), the increase of the incineration capacity was about 110% relative to the starting conditions and about 13.5% relative to the condition with 50% O-2 . The CO concentration measured near the flame front decreases drastically with the increase of O-2 content in the oxidant gas. At the chamber exit, the CO concentration was always near zero, indicating that the chamber residence time was sufficient to complete fuel oxidation in any test setting. For diesel fuel, the NOx was entirely formed in the first region of the combustion chamber. For diesel fuel, there was some increase in the NOx concentration up to 35% of O-2 ; this increase became very sharp after that. From 60 ppm, at operation with air only, the NOx concentration raises to 200 ppm at 35% O-2 , and then to 2900 ppm at 74% O-2 . The latter corresponds to six times more NOx in terms of the ratio of mass of NO to mass of residue, compared to the situation of combustion with air only. For LPG, the NOx concentrations reached 4200 ppm at 80% O-2 , corresponding to nine times more, also in terms of the ratio of mass of NO to mass of residue, in comparison with combustion with air only. Results of different techniques used to control the NOx emission during air enrichment are discussed: (a) variation of the recirculated zone intensity, (b) increase of the spray Sauter mean diameter, (c) fuel staging, (d) oxidizer staging, and (e) ammonia injection. The present paper shows that NOx emission may be controlled without damage of the increase of incineration capacity by the enrichment and with low emission of partial oxidation pollutants such as CO.

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Fourteen samples of particulate matter and semi-volatile organic compounds were collected during 6 months in the city of Campo Grande, South Mato Grosso State, Brazil. Particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected on Fluoropore PTFE filters and gas-phase PAHs were collected into sorbent tubes with XAD-2 resin. Both types of samples were extracted with a dichloromethane/methanol mixture (4:1 v/v), then the extracts were subjected to gas chromatography-mass spectrometry (GC-MS) analysis. PAHs, oxidized PAH (oxy-PAHs), phenols and methoxyphenols were identified by use of GC retention indices and MS files. The average value obtained for the sum of 15 PAHs was 21.05 ng m(-3) (range: 8.94-62.5 ng m(-3)). The presence of specific tracers and calculations of characteristic ratios (e.g. [Phe]/[Phe] + [Ant]) were used to identify the sources of the emissions of PAHs in the atmospheric samples. Levoglucosan (the anhydride of beta-glucose), retene (1-methyl-7-isopropylphenanthrene) and methoxyphenols (derivatives of syringol and guaiacol) and tracers for wood burning were identified. This study demonstrates that biomass burning from the rural zone is the main source of PAHs and emissions of other substances in the investigated site of Campo Grande. (c) 2004 Elsevier Ltd. All rights reserved.

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Suspended particles and dissolved substances in water provide reactive surfaces, influence metabolic activity and contribute to the net sediment deposition. It therefore plays an important part in the ecology and quality of the water mass. The water quality in reservoirs is crucial and it is naturally maintained by flushing and sedimentation, which continuously remove phosphorus from the water. In some reservoirs, however, these removal processes are countered by recycling of ions which could play a key role to start and/or maintain the eutrophic state. The combination of macro-, trace- and microanalysis techniques can be useful to trace pollution sources through a chemical fingerprint, whether be during an acute environmental disaster or a long-term release of pollutants. The water quality and total metal content of reservoir sediments were assessed in a reservoir, situated in the capital of the Parana State, in the South-Eastern part of Brazil. The goal of this paper was to determine the metal presence in the sediment and metal and ionic speciation in the Green River reservoir water. Water and bed sediment samples, collected from various sites during 2008 and 2009, were investigated using XRF, ICP-OES, ICP-MS, XRD and zeta potential measurements. Based on the results, the heavy metal concentration and chemical composition of the suspended matter in the water samples, as well as the sediment's chemical composition will be discussed.

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Cancer is one of the most hazardous effects to human health caused by the exposition to chemical agents. The search for new technological solutions in the industrial field led to a rapid increase in the productive sector, causing the workers to be exposed to millions of potentially toxic agents, substances potentially harmful to health. This study presents the mutagenic activity of sweepings from a sock and lingerie factory in Araraquara-Brazil, assayed with Salmonella typhimurium. All the extracts from the factory had mutagenic on activity the YG1024 strain, which is extremely sensitive to detect the mutagenic activity of the arilhydroxilamines, nitroarenes and aromatic amines. The extracts were non-mutagenics for the strains TA100 and TA98. The analysis of the mutagenicity of industrial residues is highly important because employees that participate in the production are directly exposed to those agents, as well as to the environment where the garbage is deposited.

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The use of inks containing organic solvents by the offset printing process implies in the release of volatile organic compounds to the work environment. Many of these compounds such as benzene, toluene, ethylbenzene, and the xylene isomers (well known by the acronym BTEX) are extremely toxic. In this study, the BTEX concentrations were determined in two different printing plants that use distinct types of inks: the conventional and the so-called ecological, which is manufactured based on vegetal oil. Concentration ranges were 43-84, 15-3,480, 2-133, 5-459, and 2-236 μg m-3 for benzene, toluene, ethylbenzene, m + p-xylene, and o-xylene, respectively, for the conventional printing plant. At the ecological printing plant, concentration ranges were below limit of detection (<LD)-31, <LD-618, <LD-1,690, <LD-10,500, <LD-3,360 μg m-3 for benzene, toluene, ethylbenzene, m + p-xylene, and o-xylene, respectively. BTEX concentrations are lower at the ecological printing environment than in the conventional, where mineral oil-based inks are used. However, the worker who cleans the printing matrices is exposed to high concentrations of ethylbenzene and xylenes, due probably to the cleaning product's composition (containing high amounts of BTEX). Although the BTEX concentrations found in both printing work environments were below the limits considered by the Brazilian Law for Activities and Unhealthy Operations (NR-15), the exposure to such vapors characterizes risk to the workers' health for some of the evaluated samples, mainly the personal ones. © Springer Science+Business Media B.V. 2009.

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This study was conducted to evaluate the morphologic modifications in tissues of the fruit and seed of the crambe (Crambe abyssinica Hochst. Ex R.E. Fr.) after drying at different temperatures. Fruits with a water content of 0.38 kg water/kg dry matter were harvested and manually homogenized. Drying was accomplished at 35, 45, 60, 75, and 90°C and at 21,9,7,5, and 2% relative humidity, respectively. After drying, the structure of the pericarp and tegument of the seed were evaluated and the embryo was removed from the fruit/seed for morphological analysis (structural and ultrastructural and the histolocalization of reserve substances). Drying at different temperatures did not affect the cellular structure of the tissues composing the pericarp of the fruits, but it disorganized the structure of the seed tegument. The cells of the tegument and cotyledons presented a contraction in their volumes. The lowest contractions in the cellular volumes of both the tegument and cotyledons occurred after drying at 35 and 45°C. The cytoplasm of the cotyledon cells contains oil drops and the protein bodies contain protein granules and starch grains. There were no changes in the cellular walls of the embryos of the fruits dried at different temperatures; however, ungluing of the medium lamella occurred. This damage occurred with greater intensity after drying at temperatures above 60°C. The form of the oil drops in the cytoplasm of the cotyledon cells was altered after drying. At temperatures above 60°C, the drops broke up and coalesced. After drying at 45 and 60°C, the form of some protein bodies was altered, whereas at 75 and 90°C coalescence of the protein bodies occurred in some cells. It was concluded that the identified alterations can affect the physiologic quality of crambe seeds. © 2013 Copyright Taylor and Francis Group, LLC.

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Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Os Hidrocarbonetos Policíclicos Aromáticos (HPAs) são poluentes de efeito tóxico, prejudiciais ao meio ambiente e à saúde humana, fazem parte de um grupo de compostos poluentes orgânicos persistentes (POPs), que por suas características tem impactado o ambiente, sendo por esse motivo bastante estudados. Podem estar presentes nas formas particulada, dissolvida e/ou gasosa, estando presentes em diferentes ambientes; solo, sedimento, ar, água, material particulado na atmosfera, organismos e alimentos (Kennish, 2007). As fontes naturais de HPAs incluem atividades vulcânicas, queimadas naturais, exsudação de óleos, além de processos biogênicos. HPAs antrogênicos podem ocorrer pela combustão incompleta de óleos combustíveis (automotores e industriais), queima intencional de madeira e plantações, efluentes domésticos e/ou industriais, drenagens pluviais urbanas, derrames acidentais de óleos e derivados. Hidrofóbicos e lipofílicos, essas substâncias podem ser facilmente adsorvidas em sedimentos, sendo este compartimento um importante reservatório desses poluentes. Para avaliar a presença desses compostos no ambiente, utilizou-se nesse trabalho a Cromatografia Líquida de Alta Eficiência. As amostras utilizadas no desenvolvimento e otimização da metodologia foram coletadas na baia do Guajará (Belém â PA). O presente trabalho constituiu-se dessa forma em um desenvolvimento de um procedimento metodológico (com adaptações e otimizações) para quantificar 16 HPAs em 10 pontos na baia do Guajará, Belém â PA, em duas etapas de campo, totalizando 20 amostras analisadas. Na etapa de desenvolvimento do método analítico foram testados sistemas de eluição, polaridade do sistema e fluxo do eluente entre outros. Para validação do método foram avaliados os parâmetros fidelidade, linearidade, limite de detecção, limite de quantificação do método. Razões diagnósticas foram calculadas para identificação das fontes primárias do HPAs encontrados na baia. Foram identificadas, a partir de razões diagnósticas da ΣHPAs BMM/ΣHPAsAMM; Fen/Ant; Flt/Pir; Ant/Σ178; Flt/Σ202; B(a)P/Σ228 e Ind(123cd) pireno/Σ276 as fontes primárias dos 16 HPAs estudados no sedimento da baia. A somatória das concentrações dos HPAs leves na primeira etapa de campo, variou de 132,13 ng.g<sup>-1</sup> a 1704,14 ng.g<sup>-1</sup>, a ΣHPAs dos pesados de 125,82 g.g<sup>-1</sup> a 1269,71 ng.g<sup>-1</sup> e ΣHPAs totais de 317,84 ng.g<sup>-1</sup> a 3117,06 ng.g<sup>-1</sup>.. Na segunda etapa de campo, as concentrações dos HPAs leves variou de 76,12 ng.g<sup>-1</sup> a 1572,80 ng.g<sup>-1</sup> ; a ΣHPAs pesados variou entre 213,90 ng.g<sup>-1</sup> a 1423,03 ng.g<sup>-1</sup>, e Σ HPAs totais teve concentrações de 290,02 ng.g<sup>-1</sup> a 2995,82 ng.g<sup>-1</sup>. A partir dos resultados obtidos pode-se classificar a baia do Guajará como moderadamente impactada. A combustão constitui a fonte predominante de HPAs nos sedimentos da baia do Guajará, seguida da combustão de biomassa vegetal e aporte de petróleo e derivados. A maioria dos pontos estudados nesse trabalho, nas duas etapas de campo, apresentaram concentrações de HPAs individuais acima dos VGQS.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)