The local authorities also have ordered to discharge more water from upstream hydropower projects to dilute the pollution and also stepped up testing of water samples to give timely updates.
Guangxi Jinhe Mining Co has been held responsible for discharging waste and polluting the river.
Cadmium, a chemical that is mostly found in industrial effluents, is a carcinogen.
Over the last week, local fire authorities in Hechi had put hundreds of tonnes of neutralizers made from dissolved aluminum chloride into the Longjiang river to dissolve the contamination.