Local authorities have reassured residents that it's OK to drink the tap water in Zhenjiang, East China's Jiangsu province, following a chemical spill nearby.

"A panel of experts has been sent to investigate the water pollution and the result has been made public," said Jia Yunliang, deputy director of Zhenjiang's environmental protection bureau in Jiangsu province.

The bureau said a cargo ship from the Republic of Korea, which was docked in Zhenjiang last Thursday, leaked phenol into the Yangtze River on Thursday and Friday due to a faulty valve.

Phenol, also known as carbolic acid, is an organic compound that can irritate eyes and skin. Soluble in water, if absorbed in large amounts it can damage the liver and kidneys.

The leak is suspected to have caused a pungent smell in tap water over the past week.

The government of Zhenjiang - a city of 3 million people - clarified on Tuesday that the tap water is safe after the launch of an emergency mechanism, including the use of large amounts of activated carbon.

The government statement said that the phenol concentration in the city's water was far below the level that can cause damage to the human body.

Though water quality had returned to normal, the government of Zhenjiang said that water charges will be cut in half in February to compensate for the loss of local residents.

However, Xiao Yonghong, chief physician of the No 1 Hospital Affiliated to Zhejiang University, said that the concentration of phenol could not be very low if the water's smell is pungent.

"Even if the concentration is low, there will still be a health threat to people if they drink the polluted water for a long time."

"The water quality test report should be verified by independent monitors," said Xiao.

"It would be irresponsible for local people if the local government just asked the local environmental protection bureau to investigate water quality."

The Yangtze River, China's longest, is the main source of water for many cities along its banks.

Bottled drinking water in neighboring cities, such as Nantong and Jiangyin, has sold out.

The environmental protection bureau of Shanghai also said that the city was ready to shut its main reservoir at the mouth of the Yangtze if abnormal levels of chemicals were detected, according to Reuters.

The maritime safety administration, the entry-exit inspection and quarantine bureau, and the environmental protection bureau of Jiangsu province are still investigating the pollution.