What does a solar still filter out?

The ones I've seen are for liferafts, they don't have any filters in them at all but rely on evaporating the water using heat fom sunlight and the vapour then condensing on the plastic cone and dripping down to run through a gutter to a collection tank. In theory you could put all sorts of stuff in one and the only things that end up in the collection tank will be water and any contaminant can be evaporated off and recondense on the cone. Bacteria won't evaporate off but I wouldn't be too sure about some of the toxins bacteria secrete. If its fresh piss and you wash it out afterwards you should be o.k. but don't put water contaminated with kerosene or gasoline in there and I really wouldn't be happy that all the pesticides had gone either.