Contamination - GCSE Physics Definition

What is contamination?

In GCSE Physics, contamination is defined as the unwanted presence of materials containing radioactive atoms on other materials or the accidental transfer of a radioactive substance onto or into a material.

As a result of contamination, the small amounts of the isotope in the contaminated areas emit radiation, and the material becomes radioactive. A substance is only radioactive if it contains a source of ionising radiation. Radiation cannot be blocked once an object is contaminated but can be prevented by handling sources safely.

Examples of contamination include when soil and water are polluted as a result of nuclear weapons testing and when there is a breach in a nuclear reactor and radioactive material leaks into the air.

Radioactive contamination should not be confused with radioactive irradiation. Radioactive irradiation is the process of exposing a material to ionising radiation. It is usually a deliberate process, such as the sterilisation of food or medical equipment.