Drinking Christmas tree water

Hello,My kitty is not feeling up to par today and  I just found out that my 8 month old kitten should not be drinking Christmas tree water which she has been doing!.  I have covered it with tin foil. How long till she starts feeling better?? Help please a little worried here!

What symptoms does she have?

I dont think it will be too serious but yes what kind of symptons if any have you noticed?