THE EFFECT OF SELENIUM ON THE HANDLING OF MERCURY IN THE SHORE CRAB CARCINUS-MAENAS

By means of the Hg-203 the effects of selenite on accumulation, elimin ation and tissue distribution of low levels of organic and inorganic m ercury in the shore crab Carcinus maenas were investigated, Selenite i n food or seawater seemed to prompt C. maenas to eat more food contami nated with organic mercury, but did not consistently alter the assimil ation efficiency of organic mercury, However, assimilation of organic mercury was higher from homogenized mussel in gelatinous cubes with ad ded organic mercury, than from mussels exposed to organic mercury in s eawater. Elimination of injected inorganic mercury from the haemolymph was initially speeded up by selenite in seawater, whereas elimination of injected organic mercury from the haemolymph seemed to be slowed d own initially. Selenite in seawater was found to promote translocation of injected organic mercury to the muscles. Selenite given in the foo d, but not selenite in the seawater, had the same effect on ingested o rganic mercury.