237Pu experiments with the plaice Pleuronectes platessa

Some experiments have been made on the metabolism of 237Pu — a high specific activity, gamma-emitting isotope of plutonium — by the plaice Pleuronectes platessa L. Very little of the isotope was incorporated into fish after 2 months exposure to labelled water. The oral retention from a variety of labelled foods was also very poor, and apart from the gut itself no incorporation of the isotope could, in fact, be demonstrated. Injected 237Pu was eliminated very slowly, and some evidence was obtained for an inverse relationship between the rate of 237Pu loss and the rate of growth of the fish. Growing fish incorporated a relatively larger fraction of the 237Pu body burden into skeletal material, and this was attained at the expense of the isotopic content of the liver. Very little 237Pu was incorporated into muscle.