PASSIVE AND ACTIVE CADMIUM UPTAKE IN THE ISOLATED GILLS OF THE SHORE CRAB, CARCINUS-MAENAS (L)

Cadmium uptake was followed over time (0-30 min) in isolated gills fro m the shore crab Carcinus maenas, exposed to 100 dpm Cd-109 ml-1 seawa ter (15 parts per thousand, 15-degrees-C). Effects of potassium cyanid e on cadmium uptake were also investigated. There was no significant d ifference (p > 0.05) in cadmium uptake between gills from the left or right branchial chambers. Cadmium uptake was, however, significantly h igher (ca. 20-30 %) in anterior gills (numbers 4-6) than in posterior gills (numbers 7-9). No significant difference in cadmium uptake was f ound among the three anterior gills nor among the three posterior gill s. A significant positive correlation (p < 0.001) was found between Cd -109-uptake and incubation time (0-30 min). Potassium cyanide inhibite d cadmium uptake into the gills, suggesting that there is an active tr ansport component to the uptake process. The results are discussed wit h regard to earlier studies on uptake routes of cadmium and other trac e metals in marine invertebrates.