Dead fish, toxic drinking water ... Now for the human toll
Take a look at Hechi city, a booming mining town in the northwest of Guangxi, and the jarring dissonance immediately hits you.
Misty limestone peaks stretch away from a crystalline river, all set in a lush green expanse. It would be one of the most mesmerising landscapes in the mainland, except for the dozens of smokestacks, short, tall, all grimy, lining both sides of the river.
The chimneys mostly belong to metal smelters, one of which was responsible for January's poisoning of the Longjiang, an upstream tributary of the Pearl River. The authorities are not naming the culprit, however.
In the daytime, the chimneys appear to be idle. However, locals living along the river tell of the smelters' dirty secrets. At night, they say, those chimneys churn out a vast cloud of black smoke that enters their homes and stirs them from sleep, gasping for breath.
'The filthy smoke billowing through those chimneys often chokes us awake, and we could also see flames light up the night sky,' said one resident of a city suburb, who refused to be named for fear it would bring trouble.
On January 15, the rest of the country woke up to the pollution horror gripping the city. Pictures of a river of dead fish shocked the nation and led to the discovery that 21 tonnes of cadmium, a life-threatening toxic metal had been leaked into the Longjiang.
The scale of the spill is equal to about two-thirds of the total amount of cadmium discharged nationwide in 2010. Experts warned of an immediate health and environmental challenge as well as serious long-term implications.
Villagers living along the river are still being given bottled water by the government and warned off drinking from local water sources.
Hechi and the surrounding area holds deposits of 46 types of non-ferrous metal and has some 154 heavy-metal smelters crowded along the river.
They have helped make the city the world's largest production base for indium, a rare metal essential for producing liquid crystal display screens and solar panels.
Cadmium is a by-product of processing indium. It can cause cancer and failure of the nervous system and lungs. It can contaminate the food chain through crops and other farm products. Once absorbed into the body, its harmful effects can last for up to 35 years, according to studies by the World Health Organisation and Fudan University's school of public health.
Hechi's heavy-metal smelters contribute more than half of the city's total economic output. They are the engines that have driven an economic boom over the last decade.
Yet residents say they city is paying a heavy price, with the rapid deterioration of the environment. For many, the smelters mushrooming along the river are time bombs that will turn rivers black and verdant mountains barren.
The smelters require a lot of water to operate, yet many are not even equipped with the facilities to tackle mining waste and metallurgical slag, and have been dumping industrial waste and sewage into the river for years, according to local and state media.
Routine sloppiness, lax government scrutiny, disregard for environmental standards and the local government's determination to favour protecting the industry over the public have made the situation worse.
The latest metal spill, feared to be one of the worst on the mainland in decades, came as little surprise to many residents.
'We are doomed due to worsening pollution,' said fisherman Lu Senguo, who lives in Beiji village in the city of Yizhou, which is under Hechi's jurisdiction. 'We've been hit by pollution repeatedly over the past few years and we all know it is just a matter of time before a major pollution disaster hits.'
Lu said making a living by catching fish has become increasingly difficult on the Longjiang. His family was hit hard by the contamination.
'We've never seen contamination on this scale and it is the first time that local authorities have explicitly warned us against drinking from the river,' said the 40-year-old, who has been fishing on the river for 20 years.
His family, Lu said, are victims of the city's spectacular economic rise.
Disturbingly, a study by Hechi's Centre for Disease Control found that cadmium and other heavy metals made their way into the food chain years ago.
Excessive levels of cadmium were found in as much as 20 per cent of food sold in Hechi, including meat, vegetables, eggs, milk and tea, in 2009 and 2010, according to Caixin Media, citing the study published in a medical journal last year.
Hechi has not - as yet - suffered the fate of many other areas where industrialisation has been coupled with the emergence of so-called 'cancer villages', where disease rates have spiked.
But environmentalists have long warned that such a future for the people of Hechi cannot be ruled out if local authorities continue with such reckless development.
Leaks of toxic metals such as arsenic, lead and cadmium have been common in Hechi over the past decade, threatening freshwater supplies and posing health risks for hundreds of thousands of people living along the Longjiang.
In October 2008, a chemical spill left at least 450 people in Hechi poisoned with arsenic. Last year, more than 30 children living near metal smelters in the city's suburban Nandan county tested positive for excessive concentrations of lead.
The city was named and shamed by the environment ministry in 2008 for rampant pollution. As punishment, no new industrial projects were allowed to go ahead for months.
Hechi authorities acknowledge the city must strike a balance between economic development and environmental protection. Non-ferrous metals are precious resources which need careful handling, said Liao Jincheng, a Hechi official in charge of economic planning. 'It can turn dangerous if you don't know how to minimise the hazards,' he told the China News Service.
The local government has pledged to move riverside smelters to an industrial park by 2015 and to shut down those that fail environmental standards.
But residents are not impressed. 'Local authorities have routinely vowed to crack down on heavy polluters after pollution incidents, but the situation simply gets worse,' said Qin Youyu, 60.
For Hechi, cleaning up the mess resulting from toxic leaks is a daunting challenge, so long as it continues to pin hopes of development on non-ferrous metals.
Professor Dai Tagen, a metal- pollution expert at Central South University's school of geoscience and environmental engineering in Changsha Hunan, said: 'It remains an arduous task for Hechi authorities to plug management loopholes and tighten scrutiny over so many smelters.'
And if local authorities fail to learn the right lessons from last month's cadmium spill, he warned, more disasters are sure to follow.
Hechi's pollution woes are a microcosm of the appalling problems of metal pollution facing the nation.
The rising number of health scandals has led to growing public concerns about the issue, triggering protests and unrest.
At least 10 per cent of the 120 million hectares of farmland is contaminated by metal leaks and other pollutants, Xinhua has reported.
The Beijing-based Century Weekly Magazine has reported that as much as 10 per cent of rice grown on the mainland is contaminated with toxic metals such as cadmium.
And a survey by the Ministry of Environmental Protection showed that more than 80 per cent of the sediment in the country's major rivers, lakes and reservoirs is contaminated by heavy metals.
More than 30 metal poisoning outbreaks have occurred across the country since 2009, according to statistics from last year.
In 2009 alone, the environment ministry tackled 12 metal pollution scandals that left over 4,000 people suffering lead poisoning and 180 people with excessive concentrations of cadmium.
In resource-rich southern and southwestern provinces, including Yunnan, Hunan, Guangdong and Guangxi, observers have blamed excessive mining and lax government control for the extremely high human toll - including unusually high rates of cancer.
Last year, Beijing launched a 75 billion yuan, five-year campaign to tackle the problem of metal pollution, and listed 14 provinces as particularly hard hit, among them Guangxi, Hunan, Guangdong, Jiangsu and Zhejiang.
However, the plan itself has yet to be made public. Ministry officials maintain it is a national secret.
The proportion of sediment in the mainland's major rivers, lakes and reservoirs contaminated by heavy metals