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Metal specification dynamics and bioavailability: bulk depletion effects

dc.contributor.authorPinheiro, J. P.
dc.contributor.authorGalceran, J.
dc.contributor.authorVan Leeuwen, H. P.
dc.date.accessioned2013-12-02T17:35:14Z
dc.date.available2013-12-02T17:35:14Z
dc.date.issued2004
dc.date.updated2013-11-26T16:47:44Z
dc.description.abstractUnder conditions of bulk depletion, the speciation and bioavailability of trace metals must be considered at two different time scales: (i) the time scale of the biouptake flux, as determined by diffusion of the bioactive free metal, dissociation of the bioinactive complex species, and the internalization rate; and (ii) the time scale of depletion of the bulk medium. The implications of these two time scales for the speciation dynamics are discussed in terms of experimental conditions. The geometry of the system is taken into account via a spherical cellular model. It considers a spherical organism depleting a spherical volume in a nonstirred medium and assumes linear adsorption of the metal at the biointerface and first-order internalization kinetics. In cases where the rate of biouptake is fully controlled by the internalization step, concentration gradients in the medium are insignificant. Then the biouptake becomes independent of the geometry of the system, and the model has a much simpler solution. Examples of trace metal uptake by microorganisms are analyzed: (i) cobalt uptake by Prochlorococcus in the presence of NTA, under conditions where bulk depletion is the controlling process due to the large number of organisms and high internalization rates, (ii) silver uptake by Chlamydomonas reinhardtii with significant effects of bulk depletion, due to the high internalization rate; (iii) lead uptake by Chlorella vulgaris with pratically negligible bulk depletion due to the low internalization rate of the metal; and (iv) lead uptake by intestinal Caco-2 cells, illustrating the simplification of the bulk depletion model for a system with different geometry where internalization is the rate-controlling step.por
dc.identifier.citationPinheiro, J. P.; Galceran, J.; Van Leeuwen, H. P. Metal Speciation Dynamics and Bioavailability: Bulk Depletion Effects, Environmental Science and Technology, 38, 8, 2397-24, 2004.por
dc.identifier.doi10.1021/es034579n
dc.identifier.issn0013-936X
dc.identifier.otherAUT: JPI01020;
dc.identifier.urihttp://hdl.handle.net/10400.1/3197
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherAmerican Chemical Societypor
dc.titleMetal specification dynamics and bioavailability: bulk depletion effectspor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage2404por
oaire.citation.issue8por
oaire.citation.startPage2397por
oaire.citation.titleEnvironmental Science and Technologypor
oaire.citation.volume38por
person.familyNamePinheiro
person.givenNameJosé Paulo
person.identifier.orcid0000-0001-7925-9733
person.identifier.ridE-8402-2013
person.identifier.scopus-author-id35838299700
rcaap.rightsrestrictedAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublication5caedbac-d2b5-4a86-91a7-083bf83edda3
relation.isAuthorOfPublication.latestForDiscovery5caedbac-d2b5-4a86-91a7-083bf83edda3

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