Although radioactivity is beneficial to us, it can be very dangerous also. The high dose of radioactive radiation can create serious problems in human body. Life killer cancer may cause this radiation. The preventive power against disease is reduced if someone keeps oneself in close-contact with excessive radioactive radiation for a long time. Man can be mentally disabled; even he may be physically invalid.
Radioactive iodine is also readily absorbed by the body and becomes incorporated into bones, and is therefore difficult to eliminate from the body. The radiation it emits can cause bone cancer over long periods of time. The radium on watch dials was incorporated in the paint. Workers used to paint the watch dials by hand, and some would even lick their paint brushes to make a sharper tip. They ingested radon paint, and some became ill with cancer.
The harmful effect of radioactivity can be observed from generation to generation. So the people who work with radioactive radiation should be careful. They should take proper steps to protect themselves from the excessive radioactive radiation.