Plutonium, 241Am, 90Sr, and 137Cs concentrations in some Antarctic matrices.

A radioecological survey in Antarctica shows that the 239 + 240Pu, 238Pu, 241Am, 90Sr, and 137Cs activities were detectable in nearly all the samples. The activity level of 239 + 240Pu, 241Am, and 137Cs in antarctic sediments was about 5-20 times lower than in the northern Adriatic Sea sediments, but the 238Pu activities were relatively high. It was interesting to note that the 90Sr concentrations in all the sediments tended to be low, which could be the result of the easier exchangeable behavior of 90Sr in water. High concentrations were detected in mosses and lichens and their activity levels were comparable to those in central Italy. The radionuclide ratio analyses show that the major part of 239 + 240Pu, 241Am, 90Sr, and 137Cs was a result of nuclear weapon tests. The higher 241Am/239 + 240Pu ratio was observed and it could perhaps be the result of fallout of nuclear weapon tests prior to 1962. The 238Pu/239 + 240Pu ratio in the antarctic matrices was about seven times higher than in the Northern hemisphere and it could be inferred that the major part of 238Pu was originating from the SNAP-9A satellite accident.