Mercury Speciation
Mostrando 13-20 de 20 artigos, teses e dissertações.
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13. SEPARAÇÃO E PRÉ-CONCENTRAÇÃO ON-LINE PARA ESPECIAÇÃO DE Hg EM CHORUME POR FI-CVG AAS
In Brazil, the urban solid wastes are usually discharged on landfill sites that are percolated by rainwater. This water leaches the wastes producing an effluent that is characterized by high concentration of organic matter, salts, suspended particulates and heavy metals. Mercury is one of the metals that is frequently present in different chemical forms whic
Publicado em: 2005
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14. ASSESSMENT OF MERCURY (II) SPECIES BIOAVAILABILITY USING A BIOLUMINESCENT BACTERIAL BIOSENSOR
Mercury and its compounds are highly toxic, especially methylmercury - a potent neurotoxin. It has caused a significant number of human fatalities in several accidents around the world. Due to its wide dispersion through the atmosphere, mercury is considered a global pollutant, being deposited even in remote pristine aquatic systems, where it is biomagnified
Publicado em: 2003
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15. Alternativa analítica para especiação físico-química de mercúrio em águas costeiras tropicais
The determination of the physical-chemical mercury speciation in tropical coastal waters using the derivatization technique with CVAFS detection was optimized. This methodology is able to separate the elementary, reactive, organic and total mercury phases with low operational costs. The importance of bromide chloride solution, the diluted aqua regia, used as
Química Nova. Publicado em: 2002-05
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16. Especiação de mercurio em solos contaminados por analise de termodessorção acoplada a absorção atomica
An equipment based on thermal release of mercury in solid samples was built and optimised. lt consists basically of an oven (a quartz rube wrapped in a Ni-Cr coil), coupled to an atomic absorption spectrophotometer (AAS). The output of the coupled system is a thermogram, i. e., absorbance readings as a function of temperature. The thermal release analysis wa
Publicado em: 1996
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17. Mercury Methylation by Desulfovibrio desulfuricans ND132 in the Presence of Polysulfides
The extracellular speciation of mercury may control bacterial uptake and methylation. Mercury-polysulfide complexes have recently been shown to be prevalent in sulfidic waters containing zero-valent sulfur. Despite substantial increases in total dissolved mercury concentration, methylation rates in cultures of Desulfovibrio desulfuricans ND132 equilibrated w
American Society for Microbiology.
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18. Biotoxicity of mercury as influenced by mercury(II) speciation.
Integration of physicochemical procedures for studying mercury(II) speciation with microbiological procedures for studying the effects of mercury on bacterial growth allows evaluation of ionic factors (e.g., pH and ligand species and concentration) which affect biotoxicity. A Pseudomonas fluorescens strain capable of methylating inorganic Hg(II) was isolated
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19. Effects of chemical speciation in growth media on the toxicity of mercury(II).
The toxicity of metals, including mercury, is expressed differently in different media, and the addition of soluble organics to the growth medium can have a significant impact on bioassay results. Although the effect of medium composition on metal toxicity is generally attributed to its effect on metal speciation (i.e., the chemical form in which the metal o
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20. Laboratory Study of Chemical Speciation of Mercury in Lake Sediment and Water under Aerobic and Anaerobic Conditions
Chemical speciation and partitioning of radiolabeled HgCl2 were studied in model aquatic systems consisting of undisturbed eutrophic lake sediment and water in plastic cylinders. The cylinders were either gradually made anaerobic by a gentle flow of N2-CO2 or kept aerobic by air flow. The proportion of methylated 203Hg was significantly higher, in both water