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Various tissues of common winkles, Littorina littorea (L.), experimentally exposed to cadmium (Cd) chloride were examined using light and electron microscopy and their elemental composition determined by X-ray microanalysis and histochemistry. Membrane granules in gill epithelial cells with paddle cilia contain carbonates, phosphates and sulphides associated with different cations in different types of granules. Traces of Cd have been found only in those granules containing sulphur and iron. Nephrocytes also contain small amounts of this metal in the cytoplasm of excretory cells. X-ray microanalysis reveals that concretions of basophilic cells are minor sites for Cd sequestration while BTAN-ASSG stain for unbound Cd indicates that most of the Cd is located within the lysosomes of digestive cells in association with proteins. Low amounts of the metal have been evidenced in the granules of epithelial mantle cells rich in sulphur. The results also indicate that hemocytes contain granules of calcium phosphate and iron sulphide. Cd is also associated to sulphur rather than to phosphate. These hemocytes may act as Cd carrier from gills to kidney and digestive gland. A hypothetical pathway for Cd accumulation and detoxification is suggested.

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Food consumption and growth variations related to several dosages of heavy metals (Cu, Zn, Hg and Pb) in diet were studied in the terrestrial slug Arion ater for 27 days of experimental treatment. The work reported here is part of a larger project to investigate the histological effects of metal exposure in pulmonate gastropods. Graphics on food consumption and growth vs. time for each metal, and regression for each behaviour observed are presented.

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The present study examines the structure of the lysosomal system of mature oocytes in mussels, Mytilus galloprovincialis, after a 21 day exposure to the water accommodated fraction (WAF) of two crude oils (types Ural and Maya) and of a commercial lubricant oil. The automated image analysis indicates that lysosomes, showing cytochemically demonstrable beta-glucuronidase activity, are smaller and much more numerous in oocytes of mussels treated with a 40% dose of Ural- and Lubricant-WAF when compared to controls. It is suggested that the structure of the lysosomal system of oocytes is different from that of somatic cells (i.e., digestive cells) and that budding or "fission" into smaller bodies occurs in oocyte lysosomes under certain petroleum hydrocarbon-exposure conditions. These changes in the lysosomal compartment appear to be associated to the process of gamete release or spawning.