968 resultados para CADMIUM MERCURY TELLURIDE


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The mercury rejected in the water system, from mining operations and lixiviation of soils after deforestation, is considered to be the main contributors to the contamination of the ecosystem in the Amazon Basin. The objectives of the present study were to examine cytogenetic functions in peripheral lymphocytes within a population living on the banks of the Tapajós River with respect to methylmercury (MeHg) contamination, using hair mercury as a biological indicator of exposure. Our investigation shows a clear relation between methylmercury contamination and cytogenetic damage in lymphocytes at levels well below 50 micrograms/gram, the level at which initial clinical signs and symptoms of mercury poisoning occur. The first apparent biological effect with increasing MeHg hair level was the impairment of lymphocyte proliferation measured as mitotic index (MI). The relation between mercury concentration in hair and MI suggests that this parameter, an indicator of changes in lymphocytes and their ability to respond to culture conditions, may be an early marker of cytotoxicity and genotoxicity in humans and should be taken into account in the preliminary evaluation of the risks to populations exposed in vivo. This is the first report showing clear cytotoxic effects of long-term exposure to MeHg. Although the results strongly suggest that, under the conditions examined here, MeHg is both a spindle poison and a clastogen, the biological significance of these observations are as yet unknown. A long-term follow-up of these subjects should be undertaken.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This paper presents preliminary findings for a metallomics study of mercury in the muscle of the fish from Amazonas region - Brazil, after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and subsequent evaluation of mercury by Thermal Decomposition and Amalgamation Coupled with Atomic Absorption (TTA-CAAS). It was found that mercury is present in 18 protein spots of dourada muscle (Brachyplatystoma rousseauxii) and 9 protein spots of pacu muscle (Myleus sp.). The protein spots in which they were determined the presence of mercury present molecular weight of 13.5 and 21.4 kDa and isoelectric point of 3.8 and 9.2, respectively.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Agricultural use of tannery sludge (TS) may increase risks to soils. Thus, composting is recognized as one of the most suitable alternatives for TS recycling. Field experiments were carried out to evaluate the effects of composted tannery sludge (CTS) on chromium (Cr), cadmium (Cd), nickel (Ni), and lead (Pb) accumulation in soil after 3 years. Soil samples were collected 60 days after CTS application. After 3 years, The CTS increased Cr and Ni content, while Cd and Pb contents decreased. The third year, Cr contents showed linear increases as CTS rates were applied. The application of CTS, after 3 years, in the 2.5, 5, and 10 Mg ha(-1) increased Cr significantly (140.7%, 159.7%, and 19%, respectively) and Ni (32%, 53%, and 43.8%, respectively) contents in the soil surface layer. This means that consecutive amendments of CTS increase Cr contents in the soil and plants.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Electrochemical experiments in acetic acid-acetate buffer (pH 4.5) are conducted in order to understand metallic and ionic mercury adsorption processes on the pyrite surface. The nature as well as the extent of the spontaneous interaction between pyrite and mercuric ions was evaluated. The spontaneous reduction of mercury species onto pyrite surface was confirmed. These results represent a first step for the use of mining wastes rich in pyrite for mercury pollution abatement. (c) 2005 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This experiment aim was to evaluate the contamination of the trace elements (TE) arsenic, barium, cadmium, chromium, copper, mercury, molybdenum, nickel, lead, selenium, and zinc considered in the CONAMA resolution 375 after 13 years long using sewage sludge (SS) as fertilizer in two soils: an Eutroferric Clayed Red Latosol (Rhodic Eutrudox - RE) and a Dystrophic Red Latosol (Typic Haplorthox - TH). Experiment in the field under maize cultivation had four treatments (0, 5, 10, and 20 t of SS ha(-1), dry weight), five replications and an experimental design in randomized blocks. The agrochemicals (dolomitic limestone, single superphosphate, and potassium chloride), SS, soils, and the certified reference materials were digested according to the USEPA 3051A method and the chemical elements were quantified by ICP OES. The TE contents found in the agrochemicals used should not cause immediate environmental impact. The higher TE values were found in the RE and they did not reach the agricultural (more stringent) Investigation Level (IL) yet, according to 420 CONAMA resolution. Persisting the actual SS fertilization amount applied in the soil and the TE concentration in the SS is foreseen that Ba, Cd, Cr, Cu, Ni, and Zn will be the first elements to reach the IL in the RE.

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When exhausted, the batteries are classified as hazardous waste because it has potentially toxic heavy metals and bio-accumulators, such as mercury, cadmium and lead in their internal composition functional. Due to the high level of danger, such waste should be properly designed to not allow theses chemical components to cause significant impacts on the environment. Thus, the recycling of waste in question is the best destination. In this context, was wanted to know, through a questionnaire in interview format, how the graduates of the Universidade Estadual Paulista Julio de Mesquita Filho of Rio Claro / SP are involved with this environmental issue. Since then, has been developed and implemented an environmental management for internal batteries

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Located in Apiaí, Vale do Ribeira, southern region of São Paulo state, the Usina do Calabouço areas (CIEM / CPRM) and Morro do Ouro (Parque Municipal do Morro do Ouro), were targeted for stud ies due to its old buildings, respectively a foundry in lead ore, called Experimental de Chumbo e Prata (Usina Calabouço), and a gold mine with processing plant of the gold-bearing ore produced there. Nowadays, the areas are used for public visitation, and in both places the rests of the buildings remains. Particularly in the CIEM/CPRM, due to the materials witch was produced before, it can suggest the existence of anomalous amounts of the involved metals (CIEM / CPRM) and possible contaminations by chemical products used in the improvement of the auriferous ore (P. M. Morro do Ouro). These potential contamination were confirmed with geochemical survey of soils and current sediments accomplished in both areas, for the elements arsenic, cadmium, lead, copper, mercury, silver and zinc, which were used as parameters guiding values for soil and groundwater the state of São Paulo (CETESB), and watershed values stipulated by CPRM (poor, background and anomalous), in it rising geochemistry during Folha Apiaí's execution (SG-22-X-B-V).

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To verify the levels of concentration of some heavy metals in fishes from Sorocaba river (São Paulo, Brazil) and evaluate if this contamination offers health risks to the fishermen, 63 samples of fishes collected from four points along the river were studied for cadmium, lead, chromium, nickel and mercury, with emphasis in this last, since it is the most toxic and most probable as a fish contaminant. Analyzing muscle samples by cold vapor atomic absorption spectrometry it was shown that the fishes are not contaminated. None of the five metals studied were present in prohibitive level and the fishes could be judged secure for human consume. It was also analyzed data from four years of cadmium, lead, chromium, nickel and mercury monitoring made by CETESB, from 1997 to 2000, in water from the main rivers of the State of São Paulo. The study pointed out that the majority of the monitored rivers still present contamination by those metals in a level that requires an improvement of the pollution control actions.

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Throughout the world, biomonitoring has become the standard for assessing exposure of individuals to toxic elements as well as for responding to serious environmental public health problems. However, extensive biomonitoring surveys require rapid and simple analytical methods. Thus, a simple and high-throughput method is proposed for the determination of arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se) in blood samples by using inductively coupled plasma–mass spectrometry (ICPMS). Prior to analysis, 200 ml of blood samples was mixed with 500 ml of 10% v/v tetramethylammonium hydroxide (TMAH) solution, incubated for 10 min, and subsequently diluted to 10 ml with a solution containing 0.05% w/v ethylenediamine tetraacetic acid (EDTA) + 0.005% v/v Triton X-100. After that, samples were directly analyzed by ICP-MS (ELAN DRC II). Rhodium was selected as an internal standard with matrix-matching calibration. Method detection limits were 0.08, 0.04, 0.5, 0.09, 0.12, 0.04, and 0.1 mg//L for As, Cd, Cu, Mn, Ni, Pb, and Se, respectively. Validation data are provided based on the analysis of blood samples from the trace elements inter-\comparison program operated by the Institut National de Santé Publique du Quebec, Canada. Additional validation was provided by the analysis of human blood samples by the proposed method and by using electrothermal atomic absorption spectrometry (ETAAS). The method was subsequently applied for the estimation of background metal blood values in the Brazilian population. In general, the mean concentrations of As, Cd, Cu, Mn, Ni, Pb, and Se in blood were 1.1, 0.4, 890, 9.6, 2.1, 65.4, and 89.3 mg/L, respectively, and are in agreement with other global populations. Influences of age, gender, smoking habits, alcohol consumption, and geographical variation on the values were also considered. Smoking habits influenced the levels of Cd in blood. The levels of Cu, Mn, and Pb were significantly correlated with gender, whereas Cu and Pb were significantly correlated with age. There were also interesting differences in Mn and Se levels in the population living in the north of Brazil compared to the south.