[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. The proposed hypothesis for the metal extrusion is the following: residual bodies containing the uranium precipitates are extruded into the extracellular space where they are absorbed, by phagocytosis, by the macrophagic hemocytes.