Radionuclide monitoring in molluscs inhabiting intertidal region near a nuclear installation, Gulf of Mannar, India

► 210Po and 210Pb were quantified in different tissues of intertidal molluscs of Kudankulam. ► Both the radionuclides were noticed higher in the organs associated with digestion and metabolism. ► Filter feeding bivalve molluscs registered the maximum activity of 210Po. ► The hazard quotient for molluscs was lesser than the global bench mark dose rate of 10μGyh–1. Protection of non-human biota from ionizing contaminants, especially in the vicinity of nuclear installations is a very important aspect for nuclear engineers and ecologists. In this view, a baseline data on the activity concentration of 210Po and 210Pb were quantified in different tissues of molluscs inhabiting the intertidal region along the coast of Kudankulam. The activity concentration was noticed higher in the organs associated with digestion and metabolism. Filter feeding bivalve molluscs registered the maximum activity of 210Po in their whole body compared to grazing gastropods. 210Po:210Pb ratio was calculated to be greater than unity in most of the analysed tissues. The ecological sensitivity of molluscs to the radiation exposure and the safeness of the environment was analysed by calculating the external and internal dose rate. The hazard quotient for molluscs was lesser than the global bench mark dose rate of 10μGyh–1.