Finnish engineers have poured pig manure into a contaminated pond next to an old mine, saying the bacteria in the slurry will clean up metals in the water.

The resulting black, stinking, slurry was eventually dumped around landfills in Abidjan, after Trafigura paid an unqualified local man to take it away in tanker trucks at a cheap rate.

A chemical or fluid that alters the performance of an engineered slurry or treatment fluid.