I think many people in this challenge are entering an image with any theme whatsoever and adding the word 'pure' to the front. Pure should convey completeness, being undiluted, innocence, etc. This isn't a pure example of anything.
Very nice shot, you've gotten the white balance just right here as Icebergs do have a blue shade to them. Also fits the pure challenge; even though the bergs are in Salt Water the ice itself is actually pure fresh water. Very nice.