Display options
Cite
Rocha JC, Junior ES, Zara LF, et al. Reduction of mercury(II) by tropical river humic substances (Rio Negro) - A possible process of the mercury cycle in Brazil. Talanta. 2000;53(3):551-9doi: 10.1016/s0039-9140(00)00532-4.
Rocha, J. C., Junior, E. S., Zara, L. F., Rosa, A. H., Dos Santos, A., & Burba, P. (2000). Reduction of mercury(II) by tropical river humic substances (Rio Negro) - A possible process of the mercury cycle in Brazil. Talanta, 53(3), 551-9. https://doi.org/10.1016/s0039-9140(00)00532-4
Rocha, J C, et al. "Reduction of mercury(II) by tropical river humic substances (Rio Negro) - A possible process of the mercury cycle in Brazil." Talanta vol. 53,3 (2000): 551-9. doi: https://doi.org/10.1016/s0039-9140(00)00532-4
Rocha JC, Junior ES, Zara LF, Rosa AH, Dos Santos A, Burba P. Reduction of mercury(II) by tropical river humic substances (Rio Negro) - A possible process of the mercury cycle in Brazil. Talanta. 2000 Dec 04;53(3):551-9. doi: 10.1016/s0039-9140(00)00532-4. PMID: 18968142.
Copy Download .nbib Format: NLM
Share it on

Talanta. 2000 Dec 04;53(3):551-9. doi: 10.1016/s0039-9140(00)00532-4.

Reduction of mercury(II) by tropical river humic substances (Rio Negro) - A possible process of the mercury cycle in Brazil.

Talanta

J C Rocha, E S Junior, L F Zara, A H Rosa, A Dos Santos, P Burba

Affiliations

  1. Institute of Chemistry, UNESP, PO Box 355, 14800-900 Araraquara, Brazil.

PMID: 18968142 DOI: 10.1016/s0039-9140(00)00532-4

Abstract

The evolution of elemental Hg from its environmental compounds has already been supposed to be an important process within the global mercury cycle. The present study characterizes the abiotic reduction of Hg(II) ions by typical river humic substances (HS) conventionally pre-isolated by the adsorbent XAD 8 from the "Rio Negro" near Manaus, Brazil. For the investigation of this reduction process a special reaction and Hg(0) trapping unit combined with cold-vapor atomic absorption spectrometry (CVAAS) was developed. Preconcentration of traces of mercury(II), if required, was obtained by a home-made FIA system using microcolumns filled with the Hg(II)-selective collector CheliteS(R) (Serva Company). The effect of environmentally relevant parameters such as the pH value, the Hg(II)/HS ratio and the HS concentration on the Hg(II) reduction process was studied as a function of the time. The Hg(0) production was highest at pH 8.0 and in the case of decreasing HS amounts (0.5 mg) when about 65% of initially 1.0 mug Hg(II) was reduced within 50 h. Moreover, the reduction efficiency of HS towards Hg(II) strongly depended on the HS concentration but hardly on the Hg(II)/HS ratio. The reduction kinetics followed a relatively slow two-step first-order mechanism with formal rate constants of about 0.1 and 0.02 h(-1), respectively. Based on these findings the possible relevance of the abiotic evolution of mercury in humic-rich aquatic environments is considered.

Publication Types