SS4.02 The Role of Microbiology in Trace Metal and Organic Contaminant Cycling in Aquatic Systems
Date: Wednesday, June 12, 2002
Time: 11:30:00 AM
Location: Esquimalt
 
SlaveykovaVI, CABE, University of Geneva, Geneva, Switzerland, vera.slaveykova@cabe.unige.ch
Wilkinson, K, J, CABE, University of Geneva, Geneva, Switzerland, kevin.wilkinson@cabe.unige.ch
Parthasarathy, N, , CABE, University of Geneva, Geneva, SWITZERLAND, nalini.parthasarathy@cabe.unige.ch
 
RELATIONSHIP BETWEEN LEAD SPECIATION AND ITS BIOACCUMULATION BY CHLORELLA KESSLERI
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The interaction of Pb and naturally occurring ligands including fulvic acids was examined in order to better understand the relationship between lead speciation and its bioavailability to the freshwater algae Chlorella kessleri. The potential biological impact was evaluated by relating free lead concentrations to biological uptake fluxes. In the presence of synthetic ligands such as nitrilotriacetic acid, iminodiacetic acid, citric acid and malonic acid, Pb uptake by Chlorella kessleri was governed by the free ion concentration in complete agreement with the free ion activity model. On the other hand, in the presence of fulvic acid, biouptake fluxes were significantly higher than those corresponding to the free lead ions for the reference system, possibly due to the direct interaction of fulvic acid with the algae. Adsorption and electrophoretic mobility measurements indicated that under the conditions studied, a small fraction of the fulvic acids were adsorbed to the algal surface, influencing membrane permeability.