EFFECT OF SALINITY ON THE UPTAKE OF CADMIUM BY THE BRINE SHRIMP ARTEMIA-FRANCISCANA

The effect of salinity on cadmium uptake by brine shrimp Artemia franciscana was studied in chemically defined saltwater solutions. Shrimp were acclimated to different salinities and exposed to the metal in solutions of differing salinity and composition. Within each acclimation group, the cadmium uptake decreased with increasing salinity of exposure. Most of this variation was explained by changes in the activity of the free metal ion. Among the acclimation groups, uptake increased with increasing salinity of acclimation. Most of this variation was explained by changes in the permeability of the shrimp. Uptake was not influenced by changes in the osmolarity or the concentration of any of the major cations in the solution. The integration of both chemical and biological effects of changes in salinity explains almost all variation in cadmium uptake by brine shrimp.