If some notification is disabled in the notifications settings but you still get the emails, it's a bug. Can you please elaborate? What kind of emails are you getting?
New private message, new mention in a forum post, etc.
So mentions are only implemented for debate comments and forum posts, for the former, there is a setting called New addressed comment in the notifications settings -> "Debates" tab; for the latter, there is New addressed forum post in the notifications settings -> "Forum" tab. Those settings should allow to disable or enable the notifications. But let me know if they don't work.
That option says, "You will be notified when someone mentions you in a forum post."
It doesn't say anything about emails. I actually thought this setting controls whether we get notifications on DART. I don't want to turn on-site notifications off. I just don't want email clutter.