Cu, Zn and Cd content in different tissues of the Antarctic scallop Adamussium colbecki: role of metallothionein in heavy metal homeostasis and detoxication

Abstract

Cu and Zn concentrations in the gills of the Antarctic scallop Adamussiurn colbeck! (Smith, 1902) were found to be significantly lower than in the gills of mussel Mytilus galloprovincialis (Lam) and scallop Pecten jacobaeus (L.); however, the Cd concentration was significantly higher. In digestive gland, copper concentrations were not significantly different for all 3 species, but A. Colbecki had a lower Zn concentration and an extremely high Cd concentration (ca 27 pg g-' wet wt). In A. colbeckidigestive gland, about 70 % of the total Cd was associated w t h the particulate fraction, and the rest was mostly bound to a metallothionein-type protein. In P. jacobaeus a major fraction (about 60 %) of the Cd present in the digestive gland was bound to cytosolic metallothioneins. Aging was found not to affect the concentration of Cd bound to metallothioneins in A. colbecki digestive gland, although the Cd concentration is slightly reduced in scallops > 10 yr old compared to younger (3 to 7 yr old) scallops.