Radioactive radiation is dangerous because it is ionizing. This means that it has enough energy to knock electrons out of their shells and thus turn atoms into ions.
A large amount of ionizing radiation can cause radiation burns (skin burns) and radiation sickness. Small amounts of ionizing radiation can damage DNA. This is called mutation and can later lead to cancer. If mutations occur in gametes (sex cells), they can be passed on to the next generation and can cause birth defects in newborns.
Protection from radiation
We are exposed to background radiation all the time. However, the amount is too small to harm us. But people who work with radioactive materials are exposed to more radiation and need to take precautions.
There are three ways to limit the effects of ionizing radiation: keeping a distance from the source, shielding and a time limit to exposure. For example, radioactive samples are always handled with tongs to keep a distance and stored in containers with thick lead walls for shielding.
Ionizing radiation is also used in hospitals to detect and treat cancer. Patients can be exposed to small amounts of radiation during their treatment. However, this is only done if the benefits are greater than the risks.
Irradiation and contamination
Sometimes there are accidents in nuclear power stations which can lead to radioactive materials escaping to the environment. This can lead to the irradiation and contamination of plants, animals and people. It is important to understand the difference between irradiation and contamination.
Someone is irradiated if they are close to a radioactive material and exposed to its radiation. Once the person moves away the irradiation stops.
Someone is contaminated if they get particles of radioactive material on their skin or inside their body, for example by eating or breathing. This person continues to be exposed to the radiation until all the material has decayed inside their body.
Things to do
- What is ionizing radiation?
- Give four effects of ionizing radiation on the human body.
- Why is background radiation not dangerous for us?
- State three ways to protect yourself from radiation.
- Why are radioactive samples handled with tongs and kept in lead containers with thick walls?
- What is the difference between irradiation and contamination?
- In case of a nuclear accident, what is worse? Irradiation or contamination? Why?
- Do you know any examples of nuclear accidents that have happened around the world? If yes, which do you know?