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Resumo(s)
The zinc uptake and posterior release by an aquatic bryophyte—Fontinalis antipyretica L. Ex Hedw.—was
experimentally studied in laboratory exposing the plants to different zinc concentrations in the range, 1.0–5.0 mg l 1, for
a 144 h contamination period, and then exposed to metal-free water for a 120 h decontamination period. The
experiments were carried out in perfectly mixed contactors at controlled illumination, using mosses picked out in
February 1997, with a background initial zinc concentration of 263mg g 1 (dry wt.). A first-order mass transfer kinetic
model was fitted to the experimental data to determine the uptake and release constants, k1 and k2; the zinc
concentration in mosses at the end of the uptake period, Cmu; and at the equilibrium, for the contamination and
decontamination stages, Cme and Cmr; respectively. A bioconcentration factor, BCF ¼ k1=k2 (zinc concentration in the
plant, dry wt./zinc concentration in the water) was determined. A biological elimination factor defined as BEF ¼
1 Cmr=Cmu was also calculated. BCF decreases from about 4500 to 2950 as Zn concentration in water increases from
1.05 to 3.80mg l 1. BEF is approximately constant and equal to 0.80. Comparing Zn and Cu accumulation by
Fontinalis antipyretica, it was concluded that the uptake rate for Zn (145 h 1) is much lower than for Cu (628 h 1) and
the amount retained by the plant decreased by a factor of about seven.
Descrição
Palavras-chave
Aquatic bryophytes Mosses Kinetics Zinc Fontinalis antipyretica
Contexto Educativo
Citação
Martins, Ramiro; Boaventura, Rui (2002). Uptake and release of zinc by aquatic bryophytes (Fontinalis antipyretica L. ex. Hedw.). Water Research. ISSN 0043-1354. 36:20 p.5005-5012
Editora
Elsevier