Copper and cadmium complexation by high molecular weight materials of dominant microalgae and of water from a eutrophic reservoir

Autor(es)

Gouvêa, S. P. ^[1] ; Vieira, A. A. H. ^[2] ; Lombardi, A. T.

Afiliação do(s) autor(es)

^[1] Universidade Federal de São Carlos (UFSCAR). Centro de Ciências Biológicas e da Saúde - Brasil

^[2] Universidade Federal de São Carlos (UFSCAR). Centro de Ciências Biológicas e da Saúde - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Chemosphere; v. 60, n. 9, p. 1332-1339, Sept. 2005.
• Área do conhecimento: Ciências Biológicas - Ecologia
• Assunto(s): Represamento de água Reservatórios Cianobactérias Microcystis Anabaena

Resumo

High molecular weight materials (HMWM, >12 000–14 000 Da) excreted by the two cyanophyte species (Microcystis aeruginosa and Anabaena spiroides) and a diatom (Aulacoseira granulata) which are dominant phytoplankton species in a eutrophic reservoir, Barra Bonita, Brazil were investigated as copper (Cu) and cadmium (Cd) complexation agents and their monosaccharide and elemental analysis of C, H, N and S determined. Also, HMWM obtained from the reservoir water as well as from a mixture of the three algae materials were studied. The HMWM of the cyanophytes and the mixture of the three algae materials complexed Cu and Cd, whereas the HMWM of the diatom and that from the reservoir water complexed only Cu. Two classes of ligands of intermediate to weak binding strength were obtained after Scatchard plot analysis of the titration data. The cyanophytes and the mixture HMWM presented higher conditional stability constants for Cu class-1 ligands (–9.5) than the HMWM derived from the diatom and the reservoir water (–8.8). Higher proportions of acidic monosaccharides corresponded to higher of Cu and Cd complexation, yet no relation was observed among complexation parameters and elemental analysis. This study points out Cu ligands of intermediate to weak binding strength in the excreted HMWM of dominant microalgae and in the HMWM of the reservoir water, while Cd was solely complexed by ligands isolated from the cyanophyte HMWM. (AU)

• Processo FAPESP: 99/07766-0 - Produção e destino dos polissacarídeos extracelulares de origem algal em um reservatório eutrofizado do rio Tietê (estudo de processo)
• Beneficiário: Armando Augusto Henriques Vieira
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 00/03122-0 - O papel dos carboidratos algais extracelulares na dinâmica de metais no reservatório de Barra Bonita
• Beneficiário: Sandra Protter Gouvêa
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 02/04275-0 - A influência da matéria orgânica dissolvida de origem natural na transferência do cobre em cadeias tróficas de águas continentais
• Beneficiário: Maria da Graça Gama Melão
• Modalidade de apoio: Auxílio à Pesquisa - Regular