232-Thorium and 238-Uranium are radioactive for 141 and 45 billion years, respectively; they are resident.
239-Plutonium's half-life is somewhere between 24,100 to 24,400 years, which means that it will be radioactive, toxic, and carcinogenic for 241, 000 to 244,000 years.
Radioisotopes accumulating in bone and bone marrow kill stem cells, so our bodies cannot replenish cells.
We have had and will always have exposure to radiation, a little, once considered beneficial, as in hormesis.
Nuclear weapons, nuclear power, and even nuclear well-logging have put us at risk by poisoning vitalethine, a probable radioprotector, more agressively than before.