Orientador: Mirian Cristina dos Santos / Banca: Luiz Francisco Malmonge / Banca: Michael Jones da Silva / Resumo: No presente trabalho foram empregados métodos para a determinação de chumbo em vidros provenientes de tubos de raios catódicos (CRT) e solo contaminado por este tipo de resíduo. Para as análises foram utilizadas pequenas partes dos componentes do CRT (televisão e computador) de diferentes fabricantes e desmontadas manualmente. Após a moagem, as amostras vítreas foram analisadas por MEV, EDS e DRX para determinar o tamanho de partículas e a composição elementar do material investigado. Para este estudo foi utilizada uma mistura de proporção de 1:1:1:4 em peso (canhão de elétrons, pescoço, funil e tela). Para as análises por GFAAS as amostras foram digeridas em meio ácido (2,4 mL de HCl, 1,2 mL HNO 3 , 2,4 mL de HF e 2,0 mL de H 2 O), onde cerca 125mg da amostra vítrea foram adicionados em frasco de PTFE. A concentração total de chumbo nos CRTs foi determinada por GFAAS e os valores encontrados para duas misturas provenientes de diferentes amostras foram (735,52 ± 6,12) mg kg -1 e (886,61 ± 5,49) mg kg -1 . A toxicidade da amostra foi avaliada utilizando a norma ABNT NBR 10004:2004 para resíduos sólidos. A mistura foi submetida a ensaios de lixiviação e o extrato lixiviado foi analisado por espectrometria de absorção atômica em chama (FAAS) e espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES). Os resultados indicaram que cerca de 85% do Pb presente no resíduo foi lixiviado. Os testes lixiviação realizados para os resíduos de CRTs atingiram os valores de Classe I (resíduo perigoso) de acordo com a norma ABNT NBR 10004:2004, devido à alta concentração de chumbo presente em sua composição. Os resíduos dos CRTs foram utilizados na simulação de descarte inadequado no solo e cultivo de alface em ambiente contaminado, após a colheita foram coletadas amostras de solo e a alface. Foi realizada uma avaliação biométrica da alface para ... / Abstract: In this paper methods for the determination of lead in glass from cathode ray tube (CRT) and soil pipes contaminated by this type of waste were employed. Small parts of components CRT (television and computer) from different manufacturers were used and dismantled manually for analysis. After grinding, the vitreous samples were analyzed by SEM, EDS and XRD to determine the particle size and the elemental composition of the investigated material. For this study a mixture ratio of 1:1:1:4 by weight (electron gun, neck, funnel and screen) was used. For the analyzes by atomic absorption spectrometry in graphite furnace (GFAAS) samples were digested in acid medium ( HCl 2,4 mL, 1,2 mL HNO 3 , 2,4 mL HF and 2,0 mL of H 2 O) where about 125 mg of the glassy sample was added in PTFE bottle from the quantification was performed using the method of addition of analyte. . The total concentration of lead in CRTs was determined by GFAAS and the value for two mixtures from different samples were 735, 52 ± 6, 12 mg.kg -1 and 886.61 ± 5, 49 mg.kg -1 . The toxicity of the sample was assessed using the norm ABNT NBR 10004:2004 solid waste. The mixture was subjected to leaching tests and the leaching extract was analyzed by optical emission spectrometry with inductively coupled plasma (ICP OES) and atomic absorption spectrometry in flames (FAAS). The results indicated that about 85% of Pb present in the leach residue. The leaching tests performed for waste CRTs reached values of Class I (hazardous waste) in compliance with norm ABNT NBR 10004:2004, due to the high concentration of lead present in their composition. The danger of the glass was determined using Toxicity Characteristic leashing Procedure ( TCLP ) ( SW- 846 Method 1311 , USEPA 2003) , which determines the toxicity of waste by leaching . Waste CRTs were used in the simulation of improper disposal in soil and lettuce cultivation in contaminated ... / Mestre

Highways are known to be a source of several toxic pollutants including the heavy metals lead, zinc and chromium. The need to manage highway runoff in a manner which reduces or eliminates the loading of heavy metals to receiving waters is evident, but more research has been required to develop cost-effective ways of meeting this need. Recent studies have indicated that the soil is a significant "sink" for heavy metals, allowing speculation that management practices which make use of the soil to retain metals from highway runoff should be employed. The purpose of this study is to evaluate the ability of the soil to retain heavy metals and to document some of the soil properties and reactions which are responsible for this ability. This was accomplished through a combined effort of literature review and laboratory analysis of in situ soils from the right-of-way area of 5 Central Florida highways. A total of 13 samples were analyzed, for pH, cation exchange capacity, organic matter content, grain size, and concentrations of lead, zinc and chromium. The samples were separated into 6 fractions according to density and each fraction was analyzed for lead, zinc, and chromium. The step allowed reasonable estimates of the relative importance of soil components (clay minerals, organic matter) and/or soil-heavy metal interactions (precipitation, complex formation, etc.). It was found that the soils tested can likely retain between 10 and 500 times their existing lead content. Evidence for the formation of a dense lead compound (or precipitate) in edge of pavement surface soils was found. Organic matter was identified as an important soil component for retention of lead, zinc, and chromium. However, metal retention was found to be dependent on many soil properties and chemical reactions.

No description available.

The intake of lead into the human body has become an area of major concern because high levels of lead are harmful and can cause physiological damage, especially in children. It has been suggested that adding NaSiO₃might control Pb²⁺ contamination of drinking water supplies (c.g., Thresh 1922). PbSiO₃ (am), the white, gelatinous precipitate formed by mixing Na₂SiO₃ solutions with Pb²⁺ bearing solutions, dissolves at pH<7 by the reaction: PbSiO₃ + H₂O + 2H⁺ = Pb²⁺ + H₄SiO₄ Measurements of the solubility of PbSiO₃ show that the K_eq for this reaction is 7.41x10⁵ and the ΔG_f° (PbSiO₃ (am)) is 1061.81 kJ mol⁻¹. This high value of K means that extreme amounts of a Na₂SiO₃ additive are required in a water supply system to reduce the Pb²⁺ concentration to the EPA MCL action level of 15 ppb. Furthermore, the high pH values that result from NaSiO₃ water treatments lead to the formation of lead hydroxycarbonate (hydrocerussite) because this carbonate phase is more stable in the pH range of natural waters (pH 5-8) than lead silicate. / Master of Science

Graduation date: 1993

Orientadores: Marlene Aparecida Schiavinato, Sara Adrian Lopez de Andrade / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T17:24:07Z (GMT). No. of bitstreams: 1 Souza_LucasAnjos_M.pdf: 3027770 bytes, checksum: b8bcb5d45029d8dc57eac08831f2233d (MD5) Previous issue date: 2010 / Resumo: O desenvolvimento de novas tecnologias, para exploração do meio ambiente, está intimamente relacionado ao aumento da poluição ambiental, principalmente por metais pesados (MPs). O mais preocupante é quando a contaminação por MPs ocorre em solos agriculturáveis e leva, conseqüentemente, à contaminação de animais e seres humanos. O Pb é um MP que é cumulativo nos organismos vivos e não possui nenhuma função fisiológica vital conhecida até o momento. Esse elemento está presente em baixas concentrações quando o solo não sofreu influência humana. Existe uma grande preocupação em recuperar áreas contaminadas com MPs, mas diversas técnicas empregadas são muito laboriosas e caras. Uma alternativa seria a utilização da técnica de fitorremediação, na qual se utiliza plantas com capacidade de absorver e acumular grandes quantidades do contaminante em seus tecidos para, posteriormente, coletá-las e estocá-las em locais seguros. De uma maneira geral a associação de plantas com fungos micorrízicos arbusculares (FMA) altera a fisiologia da planta e dessa maneira o potencial fitorremediador pode ser acentuado. O objetivo desse trabalho foi investigar como a associação com o FMA Glomus etunicatum pode influenciar o crescimento e o potencial fitorremediador de Canavalia gladiata, Stizolobium aterrimum e Calopogonium mucunoides em solo contaminado com chumbo. Esse experimento foi conduzido utilizando-se as 3 espécies de leguminosas herbáceas citadas acima, inoculadas ou não com FMA, crescendo em diferentes concentrações de Pb (0, 250, 500 e 1000 mg kg-1) adicionado sob a forma de acetato de chumbo. Observou-se que a germinação das sementes de nenhuma das espécies estudadas foi afetada pelo Pb no solo. No entanto, o crescimento da parte aérea e das raízes foi afetado diferentemente em cada uma dessas plantas, sendo C. mucunoides a que sofreu mais com a presença de Pb no solo. A micorrização teve um papel importante na tolerância de C. mucunoides ao Pb, enquanto que nas demais espécies tal efeito não foi observado. A micorrização favoreceu o acumulo de Pb em C. mucunoides e em C. gladiata mas não em S. aterrimum. Todas as espécies estudadas apresentaram potencial fitoestabilizador de Pb; C. mucunoides apresentou menor translocação de Pb para a parte aérea que C. gladiata e S. aterrimum. A micorrização se mostrou fundamental apenas para o desenvolvimento de C. mucunoides na presença de Pb / Abstract: The development of new technologies, to the exploration of environment, is intimately related with the increasing environmental pollution, mainly by heavy metals (HMs). This scenario can become more serious when the contamination by HMs involves agricultural soils and results in contamination of crops used in human consumption and it lead to the contamination of animals and human beings. Pb is a HM that is accumulative in the living organisms and it doesn't possess any vital physiological function known until the present. This element is present in the soil in low concentrations when the soil hasn't suffered human influences. There is a great concern in recovering polluted areas with HMs, but several employed techniques are very laborious and expensive. An alternative would be the utilization of the phytoremediation technique that involves the use of plants with capability to absorb and accumulate great amounts of the pollutant in their tissues to, afterward collect and store them in safe places. In a general maner the association of plants with arbuscular mycorrhizal fungi (AMF) alters plant's physiology and, thus the phytoremediation potential can be enhanced. The objective of this work has been to investigate how the association with the AMF Glomus etunicatum can influence the growth and the phytoremediation potential of Canavalia gladiata, Stizolobium aterrimum and Calopogonium mucunoides in a soil contaminated with lead. This experiment was carried out using the 3 species of herbaceous leguminous mentioned above, inoculated or uninoculated with AMF, growing in different Pb concentrations (0, 250, 500 e 1000 mg kg-1) added as lead acetate. It was observed that the seeds' germination of all the studied species was not affected by Pb in the soil. However the growth was affected differently in each one of the species where C. mucunoides was the one that suffered more with Pb in the soil. The mycorrhization had an important role in the tolerance of C. mucunoides to Pb while in the other species we haven't observed such effect. The mycorrhization favored the accumulation of Pb in C. gladiata and in C. mucunoides but not in S. aterrimum. All the studied plants presented phytostabilization; C. mucunoides presented lower translocation of Pb to aerial parts than C. gladiata and S. aterrimum. The mycorrhization demonstrated it self fundamental only to the development of C. mucunoides in the presence of Pb / Mestrado / Biologia Vegetal / Mestre em Biologia Vegetal