Differentiate Polluted Dirt/Water that has germs

[DragonStar]

For years I thought a differentiation with dirt and water from those with germs would be nice. Before it wasn't as big a deal to keep your dupes from mixing them with one colony. With multiple colonies in play dupes don't have oversite to keep them from mixing them now. I bring it up to avoid a pandemic. I fear for the health of my poor dupes.