Wu, from nearby Nianmengtun village, said villagers were concerned about the long-term impact on their health if they used water tainted by run-off from the aluminium plant.

'I've never seen such yellowish and murky water coming from hillside springs and in nearby rivers,' he said. 'For years, the water was so clean and clear that youngsters in my village used to drink it without boiling it first.'

Ninety-nine per cent of Jingxi's 600,000 people are Zhuang, members of China's largest ethnic minority. However, until last year its deputy Communist Party chief was Zhao Tingyong , a Shandong native who is also the manager of the aluminium plant.

Many residents complain that most of the workers at Shandong Xinfa's aluminium plant have been brought in from Shandong and that officials are getting rich while villagers' farms are ruined.

One young man who took part in the July 11 attack on the Lingwan aluminium plant said some officials in his village - with salaries of about 600 yuan a month - had built houses worth hundreds of thousands of yuan.

'We have every reason to suspect that they've been taking bribes, even though we have no concrete evidence,' he said. 'Some people have amassed huge fortunes at the expense of the underprivileged.'

The Guangxi Daily says Shandong Xinfa subsidiary Guangxi Xinfa Aluminium and Electricity Co and two other aluminium producers contributed 636 million yuan to the coffers of Baise prefecture, which oversees Jingxi, in the first half of this year.

But Nong Zhengli , a 50-something peasant from Bozhutun village, says run-off from bauxite residue left after alumina extraction means river water is no longer fit for irrigation and the cabbages he can grow now weigh only a third of what they used to and are impossible to sell. The reddish mud that covers his field has prevented him from growing tobacco for two years, costing his family of four more than 4,000 yuan.

Locals say groundwater has also been contaminated by leaks from millions of tonnes of bauxite residue stored in huge hillside valleys.

More than 100 houses in Lingwan, on the upper reaches of the Pangling River, have been submerged in two to three metres of stagnant, foul-smelling water for more than three months. Residents say explosions set off during construction of a road to a bauxite deposit blocked an underground waterway. They don't believe local officials who say an earthquake was to blame. Some homes have collapsed and hundred of villagers have been forced to live in tents provided by the local civil affairs bureau.

More that 100 Shandong-native workers and security guards wearing aluminium plant uniforms and armed with iron bars laid siege to Lingwan when work on the road resumed on July 11, a villager said.

At least two villagers were badly beaten and thousands of indignant Zhuang from 10 other villages on the lower reaches of the river rushed to their aid, scuffling with aluminium plant workers and smashing equipment at the factory that night.

The local government sent more than 1,000 riot police to disperse the protesters when 10 vehicles belonging to the plant were overturned and vandalised by the outraged villagers.

Villagers said they had no other way to vent their anger, with local media barred from reporting the case.

Wu also blames the aluminium plant for a shortage of water to irrigate village crops, saying its operations have led to a nearby reservoir almost drying up.

He and his fellow villagers have repeatedly urged the local government to examine the quality of the water in the area and see whether it is hazardous to human health but say their appeals have always been rejected, without a convincing reason being given.

Wu says he hopes the local government can fix the drinking water problem.

'We peasants have been struggling to make a living in such a poverty-stricken backwater for generations,' he said. 'To our surprise, things have only got worse since the aluminium plant came here.'