Contamination & Irradiation (AQA GCSE Physics: Combined Science)

• Contamination is defined as:

The unwanted presence of materials containing radioactive atoms on other materials

• A substance is only radioactive if it contains radioactive atoms that emit radiation
• Contamination occurs when a radioactive isotope gets onto a material where it should not be
  • This is often due to a radiation leak

• As a result of this, the small amounts of the isotope in the contaminated areas will emit radiation and the material becomes radioactive

The Assassination of Alexander Litvinenko

• Contamination is almost always a mistake or an accident
  • However, in 2006 a former Russian spy was poisoned by a radioactive isotope

• His name was Alexander Litvinenko and he was contaminated with the isotope polonium-210
  • He died because of the poisoning

It is believed that the polonium-210 that poisoned Alexander Litvinenko was secretly put into a cup of tea he was drinking

• Irradiation is defined as:

The process of exposing a material to alpha, beta or gamma radiation

• Irradiating a material does not make that material radioactive
  • However, it can kill living cells

This sign is the international symbol indicating the presence of a radioactive material

• Irradiation can be used as a method of sterilisation:
  • Surgical equipment is irradiated before being used in order to kill any micro-organisms on it before surgery
  • Food can be irradiated to kill any micro-organisms within it
  • This makes the food last longer without going mouldy