Heavy metals in the terrestrial isopod Porcellio scaber Latreille. I. Histochemical and ultrastructural characterization of metal-containing lysosomes.

Different populations of metal-loaded and uncontaminated Porcellio scaber Latreille were studied. Combined light and electron microscopical methods as well as X-ray microanalysis were applied for localization and characterization of intracellular sites of metal deposition within the small cells of hepatopancreas. By means of cytochemistry and X-ray microanalysis it was shown that membrane-limited vesicles are important sites of deposition for lead, copper, zinc and probably smaller amounts of cadmium. The vesicles also contained phosphorus. They are identical with the reported "cuprosomes" and belong to the lysosomal system. In addition, considerable amounts of lead, copper, and cadmium were found in small structures outside of membrane-limited organelles.