A POSSIBLE PATH FOR MERCURY IN BIOLOGICAL-SYSTEMS - THE OXIDATION OF METALLIC MERCURY BY MOLECULAR-OXYGEN IN AQUEOUS-SOLUTIONS

dc.creatorDEMAGALHAES, MEA
dc.creatorTUBINO, M
dc.date1995
dc.dateSEP 29
dc.date2014-12-16T11:33:09Z
dc.date2015-11-26T16:56:49Z
dc.date2014-12-16T11:33:09Z
dc.date2015-11-26T16:56:49Z
dc.date.accessioned2018-03-28T23:44:18Z
dc.date.available2018-03-28T23:44:18Z
dc.identifierScience Of The Total Environment. Elsevier Science Bv, v. 170, n. 3, n. 229, n. 239, 1995.
dc.identifier0048-9697
dc.identifierWOS:A1995RX37200009
dc.identifier10.1016/0048-9697(95)04711-5
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/76646
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/76646
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/76646
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1277491
dc.descriptionMetallic mercury has been assumed by several authors as not very reactive and, as a consequence, with little or no toxicity. The toxicity of this element is usually ascribed to alkyl-mercury ions considered to be farmed by some microorganisms. In this work, we describe experiments that clearly show that metallic mercury can be easily oxidized by molecular oxygen in aqueous solution in the presence of species such as chloride, which complex Hg(II). The experiments were carried out using metallic mercury in NaCl aqueous solution under 'open air' (temperature and agitation rate maintained constant) and under more controlled conditions (CO2 rate bubbling, i.e, pH = 4.2; air rate bubbling, i.e., O-2 constant concentration, temperature, agitation rate). The reactions were monitored spectrophotometricaly at 230 nm (HgCl42-). Significative values of the concentration of Hg(II) in the form of HgCl42- were soon attained in those solutions. For example, in 'open air' conditions, at 25 degrees C and [NaCl] = 30 g/l (0.51 mol/dm(3)), the maximal concentration of 13 ppm (6.44 x 10(-5) mol/dm(3)) of Hg(II) in the form of HgCl42- was reached in 120 min; for [NaCl] = 5 g/l at 25 degrees C, (0.085 mol/dm(3)) the maximal concentration of 0.3 ppm (1.53 x 10(-6) mol/dm(3)) of Hg(II) in the form of HgCl42- was reached in 10 min. The rate constants, k(obs), of the oxidation of the metallic mercury under the studied conditions are pseudo zero-order at 25 degrees C, and under more controlled conditions have ranged from 1.0 x 10(-7) mol/min ([NaCl] = 5 g/l = 0.085 mol/dm(3)) to 20.0 x 10(-7) mol/min ([NaCl] = 300 g/l = 5.12 mol/dm(3)). The rate constant increases with temperature, up to 25 degrees C, from where k(obs) remains constant up to 40 degrees C. From the analysis of the experimental results it was possible to propose a mechanism of oxidation of metallic mercury by O-2 in aqueous solution containing NaCl. This oxidation is proposed as a possible route for the introduction of mercury into biological systems.
dc.description170
dc.description3
dc.description229
dc.description239
dc.languageen
dc.publisherElsevier Science Bv
dc.publisherAmsterdam
dc.publisherHolanda
dc.relationScience Of The Total Environment
dc.relationSci. Total Environ.
dc.rightsfechado
dc.rightshttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dc.sourceWeb of Science
dc.subjectMERCURY
dc.subjectDISSOLUTION
dc.subjectKINETICS
dc.subjectMECHANISM
dc.subjectTOXICOLOGY
dc.subjectOXIDATION
dc.subjectWater
dc.subjectSolubility
dc.subjectToxicity
dc.subjectVapor
dc.titleA POSSIBLE PATH FOR MERCURY IN BIOLOGICAL-SYSTEMS - THE OXIDATION OF METALLIC MERCURY BY MOLECULAR-OXYGEN IN AQUEOUS-SOLUTIONS
dc.typeArtículos de revistas


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