Analytical microscopy and environment. Current developments using bioindicators of pollution by stable and radioactive elements.

Ecotoxicological investigations were performed on three sets of bioindicators. The first one concerns marine pollution of invertebrates (molluscs: the mussel Mytilus edulis and related species, crustaceans: the crab Liocarcinus puber and related species), contaminated by stable or radioactive elements originating from wastes discharged into sea water. The second one concerns freshwater pollution of vertebrates (fish: the brown trout Salmo trutta fario), contaminated by aluminium dissolved in rivers, as a consequence of an atmospheric pollution by acid rain.

[Demonstration of silver and lead contamination of oysters (Crassostrea gigas) and mussels (Mytilus edulis) in French coastal waters. Microanalytical study by secondary ion emission].

The Oyster Crassostrea gigas and the marine Mussel Mytilus edulis collected from French coastal waters of the Channel, Atlantic Ocean and Mediterranean Sea were shown to contain silver and lead. For the Oysters, the highest silver and lead levels were detected in the Marennes Oléron samples; for the Mussels, the highest silver levels were detected in the Seine Bay samples and the lead ones in the Boulogne samples. Target organs for uptake, storage and excretion, including macrophage haemocytes, were established.

[Bioaccumulation of lithium by marine organisms in European, American, and Asian coastal zones: microanalytic study using secondary ion emission].

37 species of aquatic mammals, fish, crustacea, annelids, molluscs belonging to cephalopods, gasteropods and lamellibranchs were collected from coastal waters of France: North Sea, English Channel, Atlantic Ocean, Mediterranean Sea, from Greece: Aegian Sea, from North America: Atlantic Ocean and from Japan: Pacific Ocean, Sea of Japan and East China Sea. Microanalyses which were performed on organs and tissues, using secondary ion mass spectrometry, revealed high concentrations of lithium, which is commonly used in human therapy, but is also toxic in low amounts. The retention of this metal by the marine organisms appears as a general phenomenon independent of their biotope and geographical origin; the highest lithium levels were detected in the fish muscles (= edible part).

[Bioaccumulation of lanthanum by the mussels Mytilus edulis collected from French coasts. Microanalysis by X-ray spectrography and secondary ion emission].

The common marine mussel Mytilus edulis collected from French coastal waters of the Channel, Atlantic Ocean and Mediterranean Sea was shown to contain lanthanum; higher levels were found in the samples collected from the Eastern Channel and more particularly from the Baie de Seine. 139La+ was detected within lysosomes of digestive gland, labial palp and gill epithelium, macrophage hemocytes and chitinous tissue. Lanthanum was always associated with high phosphorus contents in the lysosomes.

[Bioaccumulation of uranium by mussels, Mytilus edulis (L.) collected from the French coasts of the Channel and experimental contamination. Microanalysis by secondary ionic emission].

238U+ was detected in Mytilus edulis collected from the Pas-de-Calais and the Baie de Seine. Storage organs were mantle, digestive gland, intestine epithelium and gonad where the highest values occurred. Uranium uptake happened via gill and digestive tractus, and excretion via kidney.

[Role of lysosomes and spherocrystals in the phenomenon of uranium concentration in the mussel Mytilus edulis (L). Microanalysis by X-ray spectrometry].

The common marine Mussel Mytilus edulis, present in an uranium containing sea water at trace level, is shown to concentrate the radionuclide which is detected, with high values, in the digestive gland lysosomes and in the kidney spherocrystals. Within both of these target organelles, uranium is always associated with high phosphorus contents, with which low iron, sulfur, zinc and copper contents may be found. Thus, soluble uranium which was absorbed is then concentrated in the form of an insoluble phosphate in the storage organelles.

[Uranium concentration by crustacea: A structural, ultrastructural and microanalytical study by secondary ion emission and electron probe X ray microanalysis].

Experimental intoxications were performed on the Crayfish Pontastacus leptodactylus using hydrosoluble uranium nitrate. Investigations demonstrate that Crustacea are able to concentrate both uranium main radioactive isotopes 238U and 235U within the cuticle, gill epithelium, midgut gland (= hepatopancreas) and macrophagic hemocytes. The storage occurs within nucleus and lysosomal system where uranium is precipitated in the form of an unsoluble phosphate.

[Role of lysosomes in the phenomenon of cadmium concentration. Microanalysis by X-ray spectrography].

Investigations were performed on the midgut gland cells of the Crayfish Pontastacus leptodactylus after intoxication with cadmium. The storage of cadmium occurs within the lysosomes where the mental coexists always with sulfur zinc and copper. The simultaneous presence of these elements favours the hypothesis that metallothioneins may be located within the lysosomes.

[Effects of temperature on the bioaccumulation of cadmium by the crayfish Ponstacus leptodactylus. Microanalysis by X-ray spectrography and secondary ion emission].

Low temperatures (10 +/- 1 degrees C) induce a rapid entry of cadmium into the body across the gills and gut; higher temperatures (20 +/- 1 degrees C) induce a medium and long term absorption and storage of the metal in the digestive gland and its long term accumulation in the exoskeleton. From a methodical point of view, electron microprobe appears more suitable than secondary ion emission microanalysis for the detection of cadmium.

[Pollution in Lake Leman. Evidence for the accumulation of tin in crustacean plankton: first results obtained by X ray spectrography].

Zooplankton was collected monthly from Leman Lake, from November 1976 to April 1977. Six of the most representative species of freshwater zooplankton were analyzed: Bosmina sp, Daphnia longispina, Bythotrephes longimanus, Leptodora kindtii, Eudiaptomus gracilis and Cyclops prealpinus. All of the samples were shown to accumulate tin in their different organs and tissues where high values were generally found.

[Chemical analysis of the integument and digestive gland of Crangon crangon (Linné) (Crustacea, Decapoda) by x ray spectography. Quantitative variations in the elements of calcium, phosphorus, sulfur, and magnesium during the intermolt cycle].

Electron probe microanalysis is a very suitable method for qualitative and quantitative analysis of calcium, phosphorus, sulfur and magnesium occurring within integument and digestive gland; variations related to intermolt cycle can be compared.

[Ultrastructural aspects of Carcinus maenas L. hemocytes (Crustacea, Decapoda), parasitized by Sacculina carcini Thompson (Crustacea, Cirripeda) : reactive activity, collagen genesis].

The collagen embedding Sacculina roots is synthesized by hemocytes of Carcinus maenas and is described. Hemocytes engaged in the secretion of collagen as a reaction against a parasite constitute a defensive mechanism still largely unknown within Crustacea.

On the fine structure of the regressing ecdysial glands of carcinus maenas L. (Crustacea Decapoda) parasitized by Sacculina carcini Thompson.

The ecdysial glands (Y organs) of the crab Carcinus maenas regress in the presence of an external parasite, Sacculina carcini. This regression is more or less severe and may lead to complete autolysis. Three gradual stages in this involutionary process are described.

[Ultrastructure of the blood cells present in the Y organ of Carcinus maenas L. (Crustacea, Decapoda)].

Ultrastructural characters of the hemocytes in the Y organ of Carcinus maenas lead us to assimilate these cells to the "granulocytes". In the degenerating glands, these hemocytes evolve towards a peculiar physiological state: they show a phagocytic activity which confers on them macrophagic properties.

[Vesicles of the smooth endoplasmic reticulum in the Y organ of Carcinus maenas L. (Crustacea, Decapoda)].

The smooth endoplasmic reticulum in the Y organ cells consists of vesicular and tubular elements containing a slightly electron dense substance. The contents of these vesicles are released either at the gland surface or within the intercellular spaces. These processes which are concomitant with the hormonal activity preparatory to the molting, may represent the release of crustecdysone or of one of its precursors.