PM07 Freshwater Bivalve Ecotoxicology
Exhibit Hall
8:00 AM - Monday, 10 November 2003
(PM138) Influence of gill ventilation on accumulation of dissolved Cd by the bivalve Pyganodon grandis.
Cooper, S1, Campbell, P1, Hare, L1, 1 INRS-ETE, University of Quebec, Ste-Foy, Quebec, Canada
ABSTRACT- Metal uptake in bivalves may occur by two routes, either from solution or from food. To investigate the first of these routes, and to examine the influence of ventilatory activity on accumulation patterns of dissolved metals in freshwater bivalves, we collected adult specimens of Pyganodon grandis from a clean site in the mining area of Rouyn-Noranda, Québec, Canada. This bivalve is widespread in Precambrian Shield lakes in Canada, and has been proposed as a potential sentinel species to monitor metal contamination. The bivalves were transported to the laboratory and maintained in aquaria at 15oC. After acclimation, ventilation rates (mL/g/h) were estimated for a sub-sample of several bivalves (N=10), based on the rate at which they removed suspended algal cells from their medium. These experiments were performed on three successive days. On a given day, ventilation rates varied markedly among bivalves (e.g., <2 to ∼60 mL/g fresh wt/h; overall average = 26 ± 13 mL/g fresh wt/h). In addition, for individual bivalves ventilation rates varied from day to day. In a subsequent experiment, to observe the influence of ventilatory activity on metal accumulation, bivalves were exposed to dissolved free radio-labelled 109Cd2+ (5 nM) for a 72-h period (the animals were fed during this experiment, but with unlabelled algae, in separate feeding chambers). Whole-body and tissue specific metal concentrations were determined. About 50% of total body Cd was localised in the gills, and Cd accumulation in the gills was positively related to the bivalve ventilation rates. The respiratory physiology of the animals may be important in affecting metal accumulation patterns.
Key words: Ventilation, Cadmium, Accumulation, Bivalve