Radioactivity
Radiation
effects
Alpha, beta and gamma are all ionising radiations. They have the ability to knock electrons off atoms that they encounter. The resulting ions are chemically very reactive and can recombine is many exotic ways. Interesting if we are talking about a lump of plastic - potentially dangerous if we are talking about the human body since ionised DNA is likely to recombine in highly exotic ways leading to mutations.
It's best not to get radioactive materials either inside the body or too close to the body.
The world is naturally radioactive - so-called background radiation. The principle for waste management is that there should be no significantly increased exposure to radiation over and above this natural background.
Source: Galson Sciences Limited