09-24-2013, 02:10 PM
In my time as a coatings contractor the process is called exudation and is related to temperature and humidity. Some of the acrylic resin or surfactant comes to the surface rapidly rather than slowly drying out. Kind of a sticky or slimy residue but it will wash off over time. Not great but probably not poisonous either. On the other hand the normal oxidation of acrylic house paint over time, maybe 5% of the thickness annually, will leach heavy metals into the catchment. These are part of the paint pigment and some are added to keep (kill) mold from growing on the paint. The baked on enamel that comes on metal roofs is something that we can not reproduce but it is much better than house paint as far as catchment goes. That being said, for all I know a carbon block filter will clean it up fine.
Jay
Jay
Jay