GUANGZHOU - The density of thallium in a river that was polluted in Fengkai County in south China's Guangdong Province remains beyond the maximum level, said local authorities on Friday.

Fengkai County Environmental Protection Bureau said tests also showed that the density of cadmium in the Fengkai section of Hejiang River now met standards after it was polluted due to illegal sewage discharge in south China's Guangxi Zhuang Autonomous Region.

Guangdong and Guangxi are neighboring provinces.

Fengkai County on Saturday warned that water in a section of the Hejiang River had been tainted by upstream pollution.

The bureau warned residents living in the lower reaches of the river against drinking water or eating aquatic products.

It was confirmed that an ore-processing company caused the pollution through illegal sewage discharge.

On Tuesday, cadmium and thallium were tested and reached more than 5.6 times the recommended level in the river near the polluter.

As of Thursday evening, drinking water supply was resumed and available to 30,000 residents, who had been affected.