CADMIUM ACCUMULATION IN LITTORINA-LITTOREA, MYTILUS-EDULIS AND CARCINUS-MAENAS - THE INFLUENCE OF SALINITY AND CALCIUM-ION CONCENTRATIONS

Accumulation of waterborne cadmium in Littorina littorea, Mytilus edul is and Carcinus maenus (collected in 1988 and 1989 around the island o f Funen, Denmark) was investigated in a matrix of salinities (10 to 30 parts per thousand) and calcium concentrations (2.9 to 8.9 mM Ca++). Cadmium accumulation rates in soft parts of L. littorina, soft parts a nd shells of M. edulis and whole bodies and exoskeletons of C. maenas decreased with increasing salinity. Changes in the calcium concentrati ons accounted for 72% of the 'salinity effect' on cadmium accumulation rates in L. littorina, whereas calcium concentrations had little or n o effect on cadmium accumulation in M. edulis. Cadmium accumulation in the whole body of C. maenas was affected equally by calcium concentra tions and total salinity, whereas accumulation in the exoskeleton was mainly affected by changes in total salinity. Individual variability i n cadmium accumulation in the organs of C. maenas was greater than the variation attributable either to changes in ambient calcium concentra tions or total salinity. An appreciable amount of the inter-individual variability in the cadmium accumulation in all three species was corr elated with wet:dry weight ratios of the tissues and size of the organ isms.