Bioavailability of dissolved zinc to the common mussel Mytilus edulis in complexing environments

Abstract

The bioavailability of d~ssolved zinc to the common mussel Mjftllus edulis was studied in chemically defined seawater containing 5 different organic ligands. Zinc uptake shows saturable kinetics, indicating that it is a facilitated process. The uptake of zinc from solution is nearly linear over a 24 h period for mussel tissues exposed to a 5 pm01 I-' concentration. In most cases, metal complexation decreases zinc uptake by reducing the activity of the free metal ion. Zinc uptake rates are similar for 4 of the 5 ligands studied when the free zinc ion activ~ty is kept constant. Complexation of zinc with histidine facilitates the uptake of zlnc. Whether the n~echanism of facilitation involves the direct uptake of zinc-histidlne complexes across the membrane cannot be deduced from the present study. For the same free zinc ion activity, the avallabillty of zinc is higher in the digestive system than in the gills. The observed differences can be caused by changes in the chemical speciation of the metals in the layers lining the exchange surfaces where conditions may deviate considerably from seawater.

Modeling the effect of water chemistry on the bioaccumulation of waterborne cadmium in zebra mussels

“…The log K CaBL value is comparable to the value based on Cd accumulation datasets reported by Niyogi et al [37] for rainbow trout (namely 3.9), but well under the value for fathead minnow (5) [38]. For Zn, the value (7.4) is close to the one reported by Vercauteren and Blust [39] for the mussel Mytilus edulis (log K ZnBL value of 7.15).…”

Uptake, accumulation, and biotransformation of metal oxide nanoparticles by a marine suspension-feeder

“…The increasing concentrations of Zn in pseudofeces over time suggests an increase in rejection of feed and/or Zn from the media. Previous research suggests that Zn accumulation can reach saturation [49] and because mussel clearance rates did not change over the exposure period, mussels were most likely accumulating less Zn by excreting it in pseudofeces.…”

Factors affecting trace element uptake in the black mussel Septifer virgatus

“…A bioconcentration factor (with an equilibriurn assumption) quantified in the laboratory conditions may not be realistic for predicting metal concentration in animals in real environments where equilibna may be more often achieved than in laboratory studies. More recent studies tend to quantify the rnetal unidirectional flux rate using a short-term exposure, pnmanly because the chemical and physiological conditions are comparatively easy to manipulate (Luoma et al 1992, Roesijadi & Unger 1993, Vercauteren & Blust 1996, Wang et al 1996. This 'kinetic' approach may be more useful in understanding metal bioaccumulation than the 'equilibriurn' approach involved with a long-term exposure (Luoma & Fisher 1997).…”