Toxic metal contamination of a tributary of the Pearl River continues to threaten freshwater supplies for a city of over 3.5 million people in Guangxi as local authorities scramble to prevent carcinogenic cadmium from drifting further downstream, including to Guangdong.
Despite repeated reassurances by Guangxi authorities about the safety of its drinking water, the scare has spread in Liuzhou, one of the biggest cities in the ethnic Zhuang autonomous region, where many residents have been stocking up on bottled water since last week.
The Guangxi environmental protection department said last night seven chemical plant executives had been detained for suspicion of discharging the industrial waste, but provided no further details.
That Guangxi authorities had struggled to locate the source of the massive contamination in the two weeks since it was discovered, has further undermined their credibility, prompting questions about the government's ability to handle the spill.
A toxic slick stretching more than 100 kilometres along the Long River has reached the Nuomitan hydroelectric station, 57 kilometres upstream from Liuzhou, with cadmium levels five times above the national standard for drinking water as of yesterday, Xinhua reported.
Tests conducted yesterday morning showed that cadmium levels within a 16-kilometre radius of the city's main water plant were slightly under the safety limit, officials from the local government's emergency task force told Xinhua.
Both the Liuzhou government and the city's freshwater supplier have insisted they were capable of lowering cadmium levels enough to ensure safe drinking water and urged the public not to panic.
The Long is an upstream tributary of the Liu River. The Liu flows into the Xi River in Guangdong, which, in turn, is a major tributary of the Pearl River. Authorities predict cadmium contamination in the Liu River would peak in 10 to 15 days.
Meanwhile, local authorities have stepped up efforts to control the spill over the past 10 days, mostly by dumping more than 3,000 tonnes of neutralisers - made from dissolved aluminium chloride - into sections of river in both Liuzhou and the upstream city of Hechi, where the spill is thought to have originated some time before January 15.
Worse, Hechi Mayor He Xinxing told Xinhua yesterday that the city was running low on neutralisers, which could further hamper the pollution-control effort.
Although there are several hydropower plants upstream from Liuzhou, authorities appeared to have not yet released water to flush the pollutants downstream, which many experts say would be the most effective way to alleviate the threat.
Many Liuzhou residents have raised similar questions and expressed frustration online, complaining that they had to rely on bottled water through the Lunar New Year holiday and that authorities were dragging their feet out of fear of sending pollutants to Guangdong.
Zhou Yongzhang, director of Sun Yat-sen University's Research Centre for Earth, Environment and Resources, also questioned the authorities' response. 'The priority for the local government is to identify the pollution sources.'