Chemical and cryo-fixation for cadmium retention in a marine snail.



In the hepatopancreas of the marine snail Littorina littorea, tissue structure and elemental analysis are both adversely affected by dosage with cadmium (Cd) and preservation with an aqueous fixative saturated with hydrogen sulphide (H2S). The fixative, with and without H2S, leaches the intracellular phosphate and carbonate granules but the latter are more severely leached when H2S is added. When intracellular accumulations of cadmium are examined by X-ray microanalysis (XRMA) cadmium retention is not enhanced by H2S. To obtain a balanced XRMA of cadmium with other labile elements like Mg and K, it is necessary to use cryo-fixation.