If you don't like Romans, don't go to Rome.

You have a little problem here. You have taken your daughter into an environment that you see as unhealthy.  Yet you are unlikely to win a fight against that environment.  (It's for that very reason that people often choose to live in environments they see as healthy and in line with their values.)  I personally would be more worried about a 16 year old coming home totally drunk than I would be about her not fitting in with her friends - but she, on the other hand, undoubtedly sees things exactly opposite.

You may get through the two years without her getting in any real trouble. I don't know how common it is for young women - who apparently do this kind of thing all the time over there - to be violated, hospitalized, etc.  But even if she makes it through, how is she going to behave when she is back in the US having already experienced the wild life?

You are in Rome, but who wants their kid to act like a Roman?

The choices are probably fighting it out with your daughter - which might put a strain on the relationship, and which is likely a losing battle anyway; letting her behave according to local norms, which I can't say sounds terribly safe (though maybe it's just my American cultural bias); or getting her into a different location, either by sending her away to school somewhere else, or moving the whole family somewhere else.

Sorry I don't have an easier answer - sounds like a tough spot.

Lastly, if you haven't talked to your daughter yet about safe sex, you'd better get on that. Yesterday.