Science EPQ??

I'm doing an EPQ, which I want to be based around science, however I have no idea what topic to do.
I want it to be to do with what I'm going to study at university - I was thinking either chemistry or biochemistry. Are there any topics that link to both chemistry and biochemistry?

You need to do some research. chemistry news stories or biochem then see whether theres anything that interests you enough to do your EPQ.

https://www.chemistryworld.com/news
https://www.sciencedaily.com/news/matter_energy/biochemistry/
https://www.sciencedaily.com/news/matter_energy/chemistry/
https://phys.org/chemistry-news/biochemistry/

Do some research. read articles and pick 3-5 stories then narrow it down to see which ones have potential to be the subject of your epq.

I would definately look at the websites of organisations or universites websites doing research relating to your preferred suject, as they often may have recent news articles or information which you might find interesting. I wanted to do something medicine based but wasn't quite sure what topic to do, but I found my topic after look at the World Health Organisation Website (WHO) which had lots of different topics which lots of information! Hope this helps!