File:Deer antlers shed near Chernobyl Nuclear Power Plant.webm

English: An interesting example of the chemical behavior of fission products is provided by a pair of deer antlers on the premises of the former Ivankov Fish Combine, about one mile from the Chernobyl Nuclear Power Plant.

First, we place a sodium iodide (NaI:Tl) scintillation detector near the antlers. It registers no discernable activity above local background (although it should be noted that background near ChNPP is somewhat elevated). The NaI:Tl detector is predominately sensitive to gamma rays.

Next, we swap out the scintillator for a Geiger-Muller tube having a window that admits beta particles. The Geiger tube is an American-made CDV-700 probe. It is very sensitive to beta particles and much less sensitive to gamma rays. The antlers register many times local background on the Geiger tube, although they appeared unremarkable on the scintillator.

I submit that the explanation for this effect is the preferential concentration of strontium-90 (Sr-90), a pure beta emitter, in the bone of the antlers. Strontium's chemical behavior resembles that of the calcium that largely comprises hard bone, and so it is absorbed and retained strongly in bone (i.e. it is a "bone seeker"). On the other hand, the other major medium-lived fission product that contaminates the Chernobyl environment, the notorious gamma emitter Cs-137, is an alkaline metal, and the anions that precipitate with the alkaline-earths like Ca and Sr to form bone do not precipitate with cesium.

I don't know whether these antlers became radioactive through bioaccumulation of Sr-90 during the deer's life, or whether the chemical processes that brought the strontium there occurred mostly post-mortem.