Are gamma waves radiation

I think you mean Gamma RAYS- yes, they are most definitely a form of radiation, and potentially a very dangerous one. They are the principle form of radioactive poisoning given off by nuclear explosions and meltdowns, and very thick layers of concrete or lead are needed to stop them. They cause poisoning by knocking DNA out of order in chromosomes, resulting in gaps in chromosomal structure, or defects when the chromosome tries to repair itself and gets the order of it's genetic structure wrong. This results in DNA particles being misplaced or put in the wrong order, which chronically disables the organism that they are a part of and causes them to become sick and die, be they animal or plant life.