It can cause ionization of molecules and atoms and cleavage of bonds, resulting in altered molecular structure. Rapidly growing cells are especially sensitive - which is why radiation is used to kill cancer. Also especially sensitive are bone marrow and white blood cells. The amount of biological damage which occurs will depend on the dose received. Not all types of radiation are equally harmful.
Most doses are in the millirem range.
Background radiation is the term used to describe the radiation we are exposed to everyday, from the cosmos, rocks, soil and even our own bodies. The half-life of an isotope is a constant. There is nothing that we can do to speed up the half-life of decay. Seabrook has a 34 foot deep steel-lined concrete pool, filled with a neutron absorber, located in a secured building which can hold about 24 years worth of waste. Encase them into glass or ceramic, pack them into canisters, and bury them into the earth.