HEAVY-METAL ACCUMULATION AND CALCIUM CONTENT IN THE BIVALVE DONACILLA-CORNEA

Accumulation of heavy metals (Cu, Cd and Mn) and their effects on total Ca content were studied under laboratory conditions in sandy-bottom bivalves Donacilla cornea from an unpolluted shore in northern Sardinia. The bivalves were found to accumulate the 3 metals. Exposure at 2 different temperatures (18 and 25-degrees-C) showed significant differences only for Cu accumulation. Following decontamination in clean seawater, the body content of Cu and Mn decreased strongly, whereas that of Cd remained practically unchanged. Among organs, gills contained the highest metal concentrations. A net increase of total Ca concentration in the body was observed during metal accumulation, and the digestive gland seems the most suitable organ for studies on the effects of heavy metals on calcium homeostasis.