Undetected river pollution sparks criticism

Zhao Zhangyuan, a senior researcher with the Beijing-based Chinese Academy of Environmental Sciences, said that the Hezhou environmental protection bureau should have the ability to detect problems immediately.

"It is irresponsible for the city government to help the local environmental watchdog shirk its responsibilities with the excuse of ‘limited detection means'", he said.

"It is a pity the environmental watchdog and local residents were left in the dark while serious pollution that threatens public health was present. Although the pollutants are steadily declining now, the expert team and local authorities must act to remedy the ecology and accelerate the recovery of the river water, rather than waiting for it to recover itself."

Zhang Hui, a researcher of environmental studies with Sun Yat-sen University in Guangzhou of Guangdong province, agreed.

"Heavy rains are not an excuse for pollution. Slag containing heavy metals such as cadmium and thallium must be stored well, according to law," he said.

"If local supervisory authorities of mining and environmental protection had fulfilled their duties, there would not have been so many illegal mines operating in such an environmentally vulnerable area, which is of vital ecological significance for South China, given its dense river network."

Zhang added that an ecological compensation system should be established along important rivers' drainage areas to promote balanced growth. Provinces like Guangdong, in the downstream part of the rivers, together with the central government should subsidize provinces like Guangxi, which are upstream, to help those poor upstream regions give up their polluting industries, which are big boosters of local GDP growth.

A similar program between Anhui and Zhejiang provinces over the Fuchun River was successful in 2012. The upstream Anhui kept the river clean without affecting its economy with subsidies from Zhejiang and the central government.

Without such a program, "it is impossible for the poor regions to give up the polluting industries", Zhang said.