AQA GCSE Hazards of Contamination and Irradiation

Contamination and Irradiation

Radioactive contamination is the unwanted presence of materials
containing radioactive atoms on other materials.

Irradiation occurs when a material is exposed to ionising nuclear radiation such as alpha, beta or gamma, but does not become radioactive.

Hazards of Contamination and Irradiation

Both contamination and irradiation can be hazardous. Ionising radiation can damage the DNA within our cells, causing mutations. This can in some cases lead to cancer.

If a person were to eat food that was contaminated so it contained radioactive atoms, and those atoms became part of our body tissues, then we would become contaminated. That means that the person would continuously be exposed to ionising radiation. This would be very hazardous.

If a person enters an area where ionising radiation is present, then they would be irradiated. However, when they leave the area they are no longer exposed to the ionising radiation, so they will not be radioactive. This would be less hazardous.

Reducing hazards of Contamination

To reduce risk of contamination we need to stop the radioactive source from entering the body.

There are several ways the substance could enter the body:

1.Inhalation during breathing in

2.Ingestion when eating or drinking

3. Absorption through the skin

We can reduce the risk of contamination by wearing appropiate personal protective equipment (PPE) in risk or hazardous areas. An example of suitable PPE is a radiation suit and respirator, shown below.

The suit helps to protect him from absorption through skin, inhalation and ingestion.

The respirator cartridge filters the air, to prevent radioactive particles being breathed in.

The suit absorbs the radiation to prevent the radioactive substance and radiation from reaching the skin.

Food in at risk areas needs to be checked for radiation activity levels, this can be done with a GM counter, see below.

If the activity is at a very low level, then the food is safe to eat. If the activity is high, then the food is a hazard.

Reducing the hazards of irradiation

To reduce the hazards of irradiation, we need to stop the ionising radiation penetrating the body.

Lead lined aprons can be worn by patients to protect areas of the body from gamma rays. We only need the gamma rays to penetrate specific parts of the body that need to be treated. In this photo the radiologist on the left is placing a lead lined apron onto the patient, before her gamma ray treatment. The apron will protect part of her body from ionising radiation. The lead aborbs the radiation, preventing it from reaching the person.

Radiation suits can be worn in other areas to protect us from irradiation, this would be where the entire body needs to be protected. See the photo of the yellow radiation suit.

In some cases the amount of irradiation is too much, so robots are used for some of the tasks rather than humans. This is another way to reduce the hazard.

Practice Questions

1. Describe the difference between irradiation and contamination

2.Explain why a lead lined apron would not protect you in an environment where the radioactive gas radon is present.

3.How can the use of robots to carry out work help to reduce hazards to humans for exposure to radiation