Should the carbon dioxide mix with water underground and form carbonic acid, they say, it could leach poisonous materials from rock deep underground that could then seep out.

Experts believe the high fruit sugar, or fructose, content of juice causes uric acid - a waste product in the blood - to leach into joints, causing them to become swollen and very painful.

The vanadium phase and valence state of stone-coal with low carbon in Guizhou province were analyzed by electron probe, and a pressure acid leach experiment was carried out.