With a lack of information, we cannot tell you. We are not mind readers.
1) Describe the issue and provide a screenie if possible. For instance, what the devil is a heat-shader? I've personally never heard of that term... 2) Provide a FULL dxdiag in a spoiler tag. That last part's important.
Yeah, I noticed this around the Rift, and between the Rift and Windhelm, the volcanic steam vents. But I think I saw them effects above the bubbling water. You'd think you would get hurt if you walked there, but no.