Dose-dependent uptake and Eichhornia-induced elimination of cadmium in various organs of the freshwater mussel, Lamellidens marginalis (Linn.)

The freshwater bivalve Lamellidens marginalis was experimentally exposed to cadmium concentrations of 10, 20 and 30 ppm for 40 days for examination of cadmium uptake, after which the mussels were transferred to cleanwater, cleanwater-EDTA and cleanwater-Eichhornia for the next 40 days for measurement of cadmium elimination by gills, liver, mantle and shell of the animal. Cadmium uptake by all tissues was both dose and time dependent. Among the tissues, liver showed maximum uptake at low to moderately high cadmium concentrations, whereas uptake by gills was at high cadmium levels. The relationship between cadmium and zinc content of the tissues was expressed in a non-linear function. Maximum cadmium elimination observed in cleanwater-Eichhornia was attributable to the fact that Eichhornia was responsible for fast cadmium clearance from the water resulting in clearcut concentration gradients between tissue and water conducive to fast cadmium elimination by the test animal. (C) 1999 Elsevier Science B.V. All rights reserved.