Q: I have three choices, to do: B.Sc (physics), chemical engineering or civil engineering, which one should I choose considering that I'm in South Africa?
A: All three options that you are interested in are fairly common degrees. With the Soccer World Cup in 2010 there will be an increase in developments and infrastructure; many of these developments have already started. This means that there will be opportunities for people involved in the construction of buildings, bridges and roads.

With this in mind civil engineering may be encouraged. Do not base your decision purely on this, as it is a once off event. Time to finish a degree and gain experience will also need to be considered.
However, the other two options also provide employment opportunities in South Africa. It may be a good idea to make contact with someone in the engineering or scientific fields and ask them for their professional opinion. South Africa is alive with possibility!
Use the FirstStep website to gain website addresses for Universities across the country. The departments you have mentioned will also be able to offer advice.
Try chose a career you think will make you happy. That’s the main thing after all!