Question: What is the difference between radiation exposure and radioactive contamination?

Sarah Hunak answered on 14 Nov 2016:

Excellent question and one that people have a problem with telling the difference between. Imagine you have a bottle filled with acid. If the bottle is on the other side of the room, and closed, are you at danger from the acid? The answer is (thankfully!) no.
If I take that bottle, open it and drink it, then yes, I’m at danger from the acid.
Radiation works a little differently. It’s invisible and can have an effect on you even if you aren’t touching the source directly. So exposure is what happens when there is a sealed source of radiation on the table for example. Pretend it’s a radioactive liquid in a bottle. Radiation will be able to come out from the bottle and depending on how strong it is, might affect you. This is exposure. Where the radiation is invisibly effecting you. How strong the radiation is, how close you are to the bottle and how long you stand there will all effect your levels of exposure.
Contamination on the other hand is what happens if you spill the radioactive liquid onto the table. Now the radiation is uncontained and a contamination danger. Have you seen that advert for the NHS where they’re showing how diseases spread, and the kid sneezes then touches their mum, who prepares food, and opens a door, etc, and there’s an (often invisible) trail of contamination of the bacteria around the house? That’s how radioactive contamination works. You might not be able to see it, but it can be spread.
Radiation exposure is a problem to the outside of your body, and contamination could be a problem inside your body if you got it onto your hands, and food and ate it accidently.

Hope this helps! It’s a very good question that even some of my colleagues still struggle with so the answer isn’t very simple but shows that you have a very good scientific brain for asking!