Relationship Between Feeding-Induced Ventilatory Activity and Bioaccumulation of Dissolved and Algal-Bound Cadmium in the Asiatic Clam Corbicula Fluminea

Abstract

The influence of feeding-induced ventilatory adaptation on cadmium accumulation patterns was analyzed in quiescent Asiatic clam Corbicula fluminea studied in steady-state conditions at 15 degrees C and 25 degrees C and in air-equilibrated water. Ventilatory activity, algae inflow rate, amounts of inspired dissolved and algae-bound Cd, and whole-body and tissue-specific metal concentrations were studied during a 15-d exposure period at a low dissolved cadmium concentration of 2 microg/L and various algal concentrations of Scenedesmus subspicatus. Great care was taken not to externally stimulate animals. Four main results were obtained as regard to regulation of ventilatory activity and metal accumulation rate. First, at 25 degrees C, feeding purposes strongly stimulated ventilatory activity, while at 15 degrees C, it was independent of it except at 1 to 2 x 10(5) algae/ml. Second, Cd accumulation rate increased at higher temperature. Third, accumulation rate exhibited a positive correlation with the ventilatory flow rate. Fourth, no correlation was observed with the quantity of ventilated algae-bound Cd but, rather, with the quantity of ventilated dissolved Cd. It is concluded that the physiology of the animals can be fundamental in affecting metal accumulation process.

Modeling cadmium uptake from water and food by the freshwater bivalve Pyganodon grandis

“…Our results do, however, encompass the range of those observed for the freshwater bivalve C. fluminea by Tran et al (2002), who reported absorption efficiencies that varied from 2% to 17% depending on filtration rates, water temperature, and food density. It is perhaps not surprising that the absorption efficiency of dissolved Cd is higher in freshwater species than their marine counterparts, given that Cd is strongly complexed by chloride in seawater, reducing its bioavailability and hence its uptake in marine invertebrates (Langston and Bebianno 1990).…”

“…range reported for Corbicula fluminea, a freshwater mussel (Tran et al 2002). Although ingestion rates had little effect on the total amount of Cd accumulated in the digestive gland of P. grandis, unlike the relationship observed between dissolved Cd and [Cd] gills , ingestion rates did significantly influence the assimilation efficiency of dietary Cd in P. grandis.…”

“…Tran et al (2002) also noted that, after feeding C. fluminea a Cd-contaminated diet, 60%-70% of the total Cd burden was located in the visceral mass (which contains the digestive gland), followed by the gills (15%-20%), the muscles and foot (9%-15%), and the mantle (6%-8%). In addition, noted that after feeding M. edulis radiolabelled algae for 7 d, >60% of the total Cd burden was located in the digestive gland, followed by the mantle (*30%), the foot and muscles (*10%), and the gills (<5%).…”

“…Many factors, including food quality and quantity, have been shown to influence bivalve filtration rates. For example, lower algal densities have been shown to lead to increased bivalve filtration rates, as demonstrated by Tran et al (2002) and Fournier et al (2005) for C. fluminea. Changes in filtration rates might be expected to have relatively little effect on the relative importance of water and food as sources of Cd for P. grandis, since an increase in filtration rate would increase both the amount of dissolved Cd and the number of algal cells that enter the mantle cavity.…”

Selenium bioaccumulation in Chlamydomonas reinhardtii and Subsequent transfer to Corbicula fluminea: Role of selenium speciation and bivalve ventilation

“…Thus, microalgae play a major role in the toxic effects of Se, because they accumulate Se from the water column, partially transform it into organic Se (e.g., selenomethionine [SeMet] and selenocysteine), and transfer it to higher organisms [5]. 25, 20062693 sponses to variations in food quantity and quality [15,16]. The prevalence of Se transfer by the trophic route was shown by Zhang et al [10], who found that Se accumulation via food ( 75 Se-labeled Phaeodactylum tricornutum) in the clam Puditapes philippnarum was greater than one order of magnitude more important than that via the water.…”