In some cases, yes, in other it seems that they are sink areas that are simply constantly being nurtured with migrant animals from the surroundings (Some birds for example). Is complex.

And we need to remember that some people was poisoned just a few months ago for digging trenches in Chernobyl in the middle of a war. The danger is still there forty years later.

Poisoned is a relative term. The rates of cancers and deaths from the Chernobyl disaster varies by an incredible amount depending on what source you look at.