Retrieve sound settings

Hello,
I'm trying to retrieve the volume setting of alerts. I've done a
search using d-feet to check if some module exposes that setting, but
I could not find anything. I have also checked dconf, and found
nothing. I have read some of the gnome-control-center source code
relating to sound settings, and it seems to use hardwire pulseaudio.
Then I have two questions: does Gnome use definitely pulseaudio as
audio server (I mean on every linux/bsd distribution)? and is there
some way to retrieve the information I want without dealing with
pulseaudio APIs?

Thank you very much, I hope I expressed myself correctly