An online post claimed that Zhongting River, which runs through Shengfang Township in northern China’s Hebei province, recently turned blood-red.

An official surnamed Zhang from the Environmental Protection Bureau of Shengfang Township explained that the change in color was due to rising temperatures; the river turns red when the weather becomes warmer due to suspended iron ions in the water. The official added that local authorities are awaiting a water treatment plan from their superiors. The Emergency Center of the Chinese Ministry of Environmental Protection has already taken water samples from the river. 

Zhang said that the steel and iron industries, which are pillars of the town's economy, create a lot of iron ions and ionic compounds during production. Without any sewage treatment plant in town until 2005, all the polluted water ran directly into Zhongting River for many years. Now the town does have sewage treatment, but the sludge with iron ions at the bottom of the river cannot be removed. When spring comes, temperatures go up and the river turns blood-red due to its large quantities of iron ions. 

For the time being, authorities have stepped up the monitoring and inspections of local plants, and ensured continuous 24-hour monitoring of pollution discharge.