Evidence of high natural radiation doses in certain mid-water oceanic organisms

Concentrations of the naturally occurring radioactive nuclide polonium-210 were determined in mid-water crustaceans and fish from depths to 1500 meters. Unusually high levels were found in certain categories of organisms, indicating that these organisms were exposed to a particularly high natural radiation dose. The results have implications in terms of possible radiation effects, as a baseline against which artificial radioactive nuclides can be compared, and as a potential technique for studying the feeding behavior of mid-water organisms.