Bioaccumulation of metals by bivalves from the Limski Kanal (North Adriatic Sea). IV. Zinc distribution between Mytilus galloprovincialis, Ostrea edulis and ambient water.
From June 1979 to June 1980 the accumulation of zinc by the mussel Mytilus galloprovincialis and the oyster Ostrea edulis, from the Limski Kanal on the west coast of Istria, SR Croatia, Yugoslavia, was determined. The distribution of zinc within tissues and organs of mussels and oysters of the same length was related to the zinc concentration in the ambient water. Three physico-chemical forms of zinc can be distinguished in seawater: "ionic" dissolved (Zn electrochemically determined at the natural pH of seawater); "total" dissolved (Zn determined after sample acidification to pH 2); and particulate Zn (bound to suspended particles with a diameter 0.45 micron). The zinc content of different tissues and organs of both species increased significantly with an increase in their condition factors. Zinc concentration decreased significantly in all body parts of the oyster, but, in the mussel, only the foot was affected. Zinc concentrations in organs that are directly involved in the reproductive cycle showed a seasonal variation. The zinc concentration in the mantle of mussels was significantly and positively correlated with the "ionic" and "total" dissolved zinc content of water. Elevated amounts of particulate material suspended in the ambient water increase the filtration rate, which resulted in an accelerated accumulation of zinc by mussels, but not by oysters. Differences in zinc concentration between samples suggest that the dynamics of accumulation and loss may differ during the year; first, mainly as a consequence of the reproductive cycle in bivalves and the concentration of stimulants for filtration in the surrounding water, and second, by coastal input of Zn and by the amount of metal remobilized from the sediment.
D000818:Animals; D049872:Bivalvia / Q000378:metabolism*; D012621:Seasons; D012623:Seawater; D014018:Tissue Distribution; D014867:Water / Q000032:analysis; D015032:Zinc / Q000032:analysis / Q000378:metabolism*
D014867:Water; D015032:Zinc