[Action of cadmium on the elemental composition and cellular morphology of the hepatopancreas, kidneys and gonads of the mussel Mytilus edulis and scallop Mizuhopecten yessoensis]. / Deistvie kadmiia na élementnyi sostav i morfologiiu kletok gepatopankreasa, pochek i gonady midii Mytilus edulis i grebeshka Mizuhopecten yessoensis.

Studies have been made on the content and distribution of Cd, K, Mg, Ca, S and P in organs and cells of mussels and scallops before and after immersion in water containing cadmium chloride. In normal molluscs, the lowest content of Cd was found in the gonads; cadmium content of the hepatopancreas and kidney in the scallop is correspondingly 20 and 40 times higher than in the mussel. After immersion in water with cadmium (250 micrograms/l in summer experiments and 500 micrograms/l in spring ones), cadmium content of the hepatopancreas and kidney of the scallop was found to be also higher than that in the mussel, although the difference is less significant, being dependent on the season of year. The highest accumulation of cadmium (9.760 +/- 790 micrograms/g dry weight) was observed in the scallop kidney in summer period. After immersion in cadmium-containing water, the content of sulphur in the kidney and hepatopancreas increases, positive correlation being observed between the distribution of Cd and S. Exposure to cadmium results in the increase of Ca and Mg content in the gonads of scallops, as well as in the increase in Ca content of the gonads of mussels. Accumulation of cadmium in the gonads is rather small, maximum density of the material being observed histochemically in the gonadal wall. Morphological changes in the gonadal cells of mussels in summer period may be associated with the increase in cellular calcium.

[Effect of diesel fuel hydrocarbons and cadmium on the development of sea urchin progeny]. / Vliianie uglevodorov dizel'nogo topliva i kadmiia na razvitie potomstva morskikh ezhei.

The long-term keeping of sea urchins of the genus Strongylocentrotus in a sea water with sublethal concentrations of the diesel fuel hydrocarbons (0.04-0.3 mg/l) or cadmium (0.001, 0.05, 0.1 and 1 mg/l) on the progeny development was studied. Sea urchins S. nudus are more resistant against cadmium than S. intermedius. The effects of long-term keeping of S. nudus in a sea water with hydrocarbons and of S. intermedius in a sea water with cadmium on the progeny development proved to be similar. The effects of both the toxicants were most distinct at the gastrula stage: the archenteron formation was delayed. Hydrocarbons exerted more toxic effects by the following criteria: decrease in the size of larvae, asynchrony and delay of development and frequency of defects.

[Morpho-functional changes in the ovaries of the sea urchin Strongylocentrotus intermedius after exposure to cadmium]. / Morfofunktsional'nye izmeneniia v iaichnikakh morskogo ezha Strongylocentrotus intermedius pri deistvii kadmiia.

The ovaries were studied in the sea urchins kept in a sea water added with 1, 50 and 100 micrograms/l cadmium chloride for 5, 15, 40, 72 and 130 days. The gland reaction depended on the drug dose and exposure. A short exposure (5 and 15 days) stimulated the development of a larger, as compared with the control, number of oogonia and raised the activity of acid and alkaline phosphatases. A long exposure decreased the number of germ cells, decelerated their growth, destroyed gametes and accessory cells, inhibited the activity of alkaline phosphatase. The cadmium accumulation in the ovaries was noted only on the 130th day at concentrations of 50 and 100 micrograms/l. The monitoring of morphological and biochemical indices allowed to conclude that cadmium exerted a toxic effect on the sea urchin ovaries.