Uptake of uranium by Anadara granosa (Linnaeus, 1758) under laboratory conditions

Abstract

The uptake, loss, and retention of uranium by the marine bivalve Anadara granosa (Linnaeus, 1758) at ambient concentrations of 2 ppm and 5 ppm in seawater were investigated under controlled laboratory conditions. At both concentration levels, the animals reached apparent equilibrium with the active medium within 5 – 6 days and released uranium at a rapid rate when transferred to a non-active medium. However, the uranium content of 5 ppm turned out to be toxic to the animals, resulting in physiological stress and mortality. The acute concentration factors of < 1 for uranium in edible portion appear to be much lower than the chronic concentration factors of 7 – 8 ppm obtained for the field population of the bivalve in the natural habitat. The present study emphasises the importance of both concentration factors while estimating the maximum permissible concentrations of uranium in seafood for human consumption. Updated insights from recent bioaccumulation studies and marine radioecology are incorporated to contextualise the findings of this classical study within current scientific understanding.