There is also the interesting process of chemical Oxidation, which occurs naturally, and with environmental clean up. ( Various treatment processes: ozonation,

There is also the interesting process of chemical Oxidation, which occurs naturally, and with environmental clean up. ( Various treatment processes: ozonation, peroxide injection, etc.) The break down by products of complex chemicals, are often more toxic (long term hazard to organisms, including humans.) For example, Tetra fluoroethylene, may easily breakdown down to Tri fluoroethylene. There are even more toxic by products, further down the break down chain. Soil chemistry is very complicated, and interesting. EPA has very good articles following these processes across hundreds of superfund sites, across the USA.