Dangers of Radiation (Cambridge O Level Physics)

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Katie M

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Dangers of Radioactivity

  • Ionising radiation can damage human cells and tissues at high doses:
  • This could be in terms of:
    1. Cell death
    2. Tissue damage
    3. Mutations
    4. Cancer

  • As a result, its use needs to be kept to a minimum
  • However, the benefits of using radiation in medicine can out way the potential risks
    • The risks posed by the radiation are smaller than the risks associated with leaving the condition untreated

  • For example, if a person has a cancerous tumour that is likely to kill them, then it is less of a risk to use radiotherapy than to leave the tumour

Tissue Damage

  • Radiation is effectively used to destroy cancerous tumour cells
  • However, it can cause damage to healthy tissue if it is not properly targeted
  • This is mostly from high-energy radiation such as gamma rays and X-rays

Mutations

  • If the atoms that make up a DNA strand are ionised then the DNA strand can be damaged
  • If the DNA is damaged then the cell may die, or the DNA may be mutated when it reforms
  • If a mutated cell is able to replicate itself then a tumour may form
    • This is an example of cancer, which is a significant danger of radiation exposure

Mutation of a Cell by Ionising Radiation

Diagram showing the damage caused to DNA by ionising radiation. Sometimes the cell is able to successfully repair the DNA, but incorrect repairs can cause a mutation

  • Acute radiation exposure can have other serious symptoms:
    • It can cause skin burns, similar to severe sunburn
    • Radiation can reduce the amount of white blood cells in the body, making a person more susceptible to infections by lowering their immune system

  • Because of this, it is very important to handle radioactive sources carefully

Safe Storage

  • The risks associated with handling radioactive sources can be minimised by following a few simple procedures:
    • Sources must be stored in lead-lined boxes and kept at a distance from people
    • Sources must be handled for the minimum time possible and then returned to their boxes immediately
    • During use, sources should be handled with a pair of tongs at arm’s length
  • When using tongs, gloves and safety specs are usually unnecessary when handling radioactive materials, unless there is a risk of the material leaking onto other items

Hazard Symbol for Radioactivity

Radioactivity danger sign, IGCSE & GCSE Physics revision notes

Whenever you see this symbol, it means a source of ionising radiation is nearby and you should proceed with caution

Disposing of Radioactive Waste

  • If an isotope has a long half-life then a sample of it will decay slowly
    • Although it may not emit a lot of radiation, it will remain radioactive for a very long time

  • Sources with long half-life values present a risk of contamination for a much longer time
  • Radioactive waste with a long half-life is buried underground to prevent it from being released into the environment

Disposal of Radioactive Waste

Radioactive waste

Radioactive waste with a long half-life must be buried deep underground

Worked example

A student plans to use a gamma source to conduct an experiment.

List four precautions that the student should take in order to minimise the risk to themselves when using the source.

Answer:

The student should...

  1. Keep the source in a lead-lined container at all times when not in use
  2. Use tongs to move the source, rather than handling it directly
  3. Ensure an adequate distance is kept between them and the source during the experiment
  4. Keep a record of the date and time that the radiation has been used

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Katie M

Author: Katie M

Expertise: Physics

Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.