Uptake from Water, Internal Distribution and Bioaccumulation of Selenium in Scenedesmus obliquus, Unio mancus and Rattus norvegicus: Part B

Se-75-selenite transfer was investigated in a phytoplankton-mussel-rat food chain model consisting of Scenedesmus obliquus (Turpin) Kutzing, Unio mancus Lamark and Rattus norvegicus Berkenhout. Se-75-metabolized forms were investigated in order to identify potential critical steps in the food chain, as well as its relative bioavailability looking also at intracellular, cellular and organ partitioning. Tissue and intracellular distribution of Se-75 in mussels fed with Se-75-S. obliquus was different compared to those exposed only to inorganic Se-75-selenite. The intracellular distribution of Se-75 in the hepatopancreas and mantle of mussels fed Se-75-microalgae was similar to hepatic and renal distributions in rats, suggesting that their stomach dissociated larger Se-75-containing molecules. The Se-75 partitioned from water (culture medium) to microalgae showing a bioconcentration factor of 435. The bottleneck in the trophic transfer of Se-75 occurred between S. obliquus-U. mancus. From microalgae to mussels and subsequently to rats no bioaccumulation was verified.