Sludge

In the industrialized parts of the Manifold, sentient beings sometimes, knowingly or not, create substances which build up in the environment and resist destruction by time or the elements. These pollutants are slowly accumulating, forming accretions in the depths of the world and slowly poisoning the Manifold's ecosystems, requiring intentional intervention from the same sentient beings to destroy it. These pollutants are collectively known as 'sludge.'

Mechanics & Inner Workings

While masses of sludge may hold residual toxicity, an equivalent quantity of it is made up of inert materials (i.e. plastics) which simply bioaccumulate rather than breaking down. These inert materials are no less dangerous than the toxic ones, however, because their inertness also means that they are difficult for living beings to expel or differentiate from otherwise nutritious food items.

Significance

These substances are colloquially known as the 'sludge' because the term better evokes the substance's extreme persistance and resistence to degradation than abstract terms like 'waste' or 'pollutants.' After all, even biodiesel and its byproducts can be recycled with the right application of chemistry; once it has become sludge, however, very little can be done with it.
Far thinking scientists and industrialists - especially among members of the Manifold Conservation Society, the Biocosmist faith, and the international hazardous-condition salvage reclamation community - are working on methods of environmental remediation to solve this long-term threat to the survival of the Manifold Sky. Current best practices include reduction of non-degradable materials at the production end, recycling of such materials as much as possible when they are created, and the destruction of any sludge found by extreme heat and chemical assault (e.g. incinerators, supercritical water reactors, strong acid/base baths, or even volcanic vents).

Item type

Compound

Rarity

True sludge is uncommon in the world as of the year 10,000 AR. However, the amount of sludge extant in the world inexorabily increases, as environmentally degradable pollutants are not sludge by definition.