Provincial authorities in South China's Guangdong province have set up a special task force to further investigate water pollution caused by a dam collapsing at a mine, killing a huge amount of fish in the neighboring Guangxi Zhuang autonomous region.

In Wuzhou of Guangxi, the city government received reports from local fishermen that more than 94,000 kg of fish had been killed in the city, situated in the lower reaches of the Qianpai and Huanghua rivers, after a dam at the Yinyan Tin Mine collapsed on Sept 21 when Typhoon Fanapi struck Guangdong last week.

The Yinyan Tin Mine, owned by the Fujian-based Zijin Mining Group, is located in the upper reaches of the two rivers in Xinyi city, western Guangdong province. Waste water and other poisonous material were reportedly discharged from the mine when its dam collapsed.

Authorities in Wuzhou have launched an investigation to establish responsibility for the fish that were killed in the accident. The city government has also issued a notice prohibiting residents from cooking and processing the fish and other aquatic products that perished in the incident.

Deng Hanchao, a publicity official for the government of Maoming city, which administers Xinyi, did not rule out the possibility that the fish in the lower reaches of the two rivers were killed by polluted water discharged from the mine.

However, he said the real reason for the mass fish deaths will not be known until after the investigation.

An initial investigation by the local environment protection department indicated that the water of the Qianpai and Huanghua rivers had not been seriously polluted after the mine dam collapsed, Deng told China Daily.

However, Li Dezhi, a farmer from Shuanghe village in Xinyi's Qianpai township, said the tin mine discharged a large amount of waste water and poisonous ore sand in the dam collapse last week.

"It will be three to four years before the polluted farmland can be ploughed again," Li said.

Tang Hao, secretary-general of the Guangdong provincial government, said the tin mine should bear the responsibility for the collapse of its dam.

"But whether the discharge of ore sand from the mine in the dam collapse caused serious water pollution and killed the fish in the lower reaches needs to be investigated further," he said.

Tang urged the province's environmental protection bureau and related departments to conduct a thorough inquiry into the case.

In the aftermath of Typhoon Fanapi, the government of Xinyi has decided to remove a hidden flood peril by exploding a dam that used to protect thousands of villagers in the lower reaches of the Qianpai River.

The 7.7-meter-high dam sustained serious damage in the typhoon and now poses a threat to local villagers in Qianpai township.

Soldiers began to plant explosives around the dam on Tuesday and the detonation is due to take place in three days, according to local media reports.

Floods and landslides triggered by the typhoon killed at least 100 people, while 41 were still missing in Guangdong province as of Tuesday.

More than 1.23 million residents from 186 townships in 22 cities and counties were affected by the disaster.