I am playing a Seablock with normal land and biters. From what I can see the painted landfill doesn't absorb any pollution, but it is a bit hard to tell for sure.

Does anyone know what the pollution situation is?

The default Sea Block map settings have pollution disabled. Did you re-enable it? There are no biter spawners so pollution does nothing except turn the water green.

I changed the mod to start with normal land and rampant biter nests, plus pollution switched back on. I am not much of a programmer and some more bob angels stuff is showing though in places, but it has the seablock tech and resources to start, plus I set it to no resource patches in the start menu.

Consequently pollution emissions, absorption and what landfill does to it are critical issues.

With evolution set to 0,150,1 and 20 times science requirements it is quite a good scenario so far, though the biters seem a bit too easy at this point. I am still working my way through red science so that might change.