Residents living on the banks of the Pearl River where it runs through the capital of the southern Guangdong Province, demanded environmental authorities explain and clean up the stinky black water near their home.
The river near Nan'an Road in Guangzhou turned black for about three hours on Tuesday, said a woman surnamed Tang. She lived in the Ligangnanwan residential community on the bank, the local Yangcheng Evening News reported on Wednesday.
The paper carried a photo datelined Tuesday, showing the ink-like water joining another tributary, usually a muddy color, at a curve on the Pearl River.
Tang said the black water had appeared before and usually lasted several hours. The locals suspected it was caused by pollutants discharged by a power plant up the river.
A Guangzhou municipal environment protection bureau official who inspected the water course on Tuesday concluded the black substance was not wastewater from the factory, but riverbed silt whipped up by the tributaries. He said the factory discharge may have exacerbated the situation.
But local residents had their doubts and contended the silt alone couldn't account for the situation. They demanded the authorities to further investigate the incident.