[en] This paper presents the concentration of ²¹⁰Po in five species of bivalve molluscs (Donax faba, Donax cuneatus, Scapharca inaequivalvis, Pinctada vulgaris and Perna indica) from Gulf of Mannar, southeast coast of India. The levels of ²¹⁰Po among the tested species ranged from 65.8 to 2,668.9 Bq Kg^-1. Analyses indicated that the soft tissues of the bivalves registered a higher level of ²¹⁰Po than the shells. Further, analyses also showed a non-uniformity in the distribution of ²¹⁰Po in the various internal organs. The concentration recorded in them maintained the following descending order: digestive glands > viscera > gills > foot > mantle > shell. It is evident that P. indica could be used as a sentinel organism for ²¹⁰Po in the ambient waters. (author)