Ionising radiations

Normally, atoms are neutral. They have the same number of protons in the nucleus as they have electrons orbiting in the energy levels around the nucleus.

Atoms can, however, lose or gain electrons due to collisions or other interactions, often with nuclear radiation. When they do, they form charged particles called ions:

  • if the atom loses one or more electrons, it becomes a positively-charged ion
  • if the atom gains one or more electrons, it becomes a negatively-charged ion

Radioactive materials are hazardous. Nuclear radiation can ionise chemicals within a body, which changes the way the cells behave. It can also deposit large amounts of energy into the body, which can damage or destroy cells completely. Ultraviolet, x-rays, alpha, beta and gamma radiations are all examples of ionising radiations. Molecules in cells can be altered as well as the DNA.

Some of the effects that radiation has on a human body are shown below.

EyesHigh doses can cause cataracts.
ThyroidRadioactive iodine can build up and cause cancer, particularly during growth.
LungsBreathing in radioisotopes can damage DNA.
StomachRadioactive isotopes can sit in the stomach and irradiate for a long time.
Reproductive organsHigh doses can cause sterility or mutations.
SkinRadiation can burn skin or cause cancer.
Bone marrowRadiation can cause leukaemia and other diseases of the blood.