Technetium: Uptake,organ distribution and loss in the mussel, Mytilus Californianus (Conrad) and the oyster Crassostrea gigas (Thunberg)

The bivalve molluscs Mytilus californianus and Crassostrea gigas were exposed to filtered seawater containing the isotope ^95mTc added as pertechnetate (TcO₄^?) to study the biokinetic behaviour of this element. Whole body concentration factors for both organisms at equilibrium were small (CF = 1·3–1·5); individual organ concentration factors were highest for the visceral mass in both. Loss rates determined both in the laboratory and under field conditions were biphasic for both molluscs; initial loss of Tc was rapid with slightly more than 50 % of the initial label being lost within 10 days. Thereafter, loss rates decreased and whole body biological half-lives ranged from 80 to 134 days. Neither I^? nor IO₃^? affected the uptake of Tc by M. californianus even when concentrations of these anions exceeded those normally present in seawater by two orders of magnitude.