Xinhua Insight: China fights soil pollution with science

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Publish time: 18th April, 2014      Source: Xinhua News Agency
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GUANGZHOU, April 17 (Xinhua) -- Chinese scientists hope new technologies can save the country's farmland from widespread soil pollution.

 

Scientists in south China's Guangdong Province have discovered a chemical derived from a type of clay mineral that can help control heavy metal residues in farm soil to prevent them from entering crops.

 

The material, called "Mont-SH6," can stabilize heavy metals such as cadmium and copper to reduce their toxicity and activity, explained Liu Wenhua, chief engineer of Guangdong provincial geological experimental test center.

 

Experiment results suggest that heavy metal levels dropped significantly in the tested rice.

 

"The level of cadmium content in rice dropped by more than 90 percent," said Liu.

 

"The technology is suitable for large-scale restoration of farmland because it is relatively cheap and effective," said Zhao Qiuxiang, head of the research team.

 

Zhao said restoration of each mu (one-fifteenth of a hectare) costs only several hundred yuan, and costs will be cut after large-scale application.

 

But Liu Wenhua said industrial application of the technology requires time. "At least two years are needed for large field experiments before it enters the market," said Liu.

 

Chinese authorities have become increasingly concerned about the risk to food posed by widespread contamination of farmland.

 

Official statistics suggest that more than 3.33 million hectares of China's farmland is too polluted for crops, after decades of extensive development left poisonous metals and discharge to seep into soil and crops.

 

Heavy metal pollution alone has resulted in the loss of 10 million tonnes of grain and the contamination of another 12 million tonnes annually, incurring 20 billion yuan (3.17 billion U.S. dollars) in direct economic losses each year, according to official estimates.

 

The discovery last year of dangerous levels of cadmium in rice produced in central China's Hunan Province, the country's top rice-growing region, caused an outcry among the public.

 

Chinese Premier Li Keqiang declared war on pollution during March's parliamentary session and pledged to fight it with the same determination the country battled poverty.

 

Following Li's words, a plan was passed in April to set up pilot projects in six heavily polluted regions, according to the Ministry of Environmental Protection.

 

According to the report, the government will allocate more than 1 billion yuan to each demonstration pilot to support soil pollution treatment.

 

The plan, together with a soil pollution law in the drafting stage, is expected to focus on protecting food supplies and ensuring that contaminated crops do not enter the food chain.

 

However, the pilot projects are small and cannot begin to redress the extent of the problem, according to experts. One of the major concerns is who will eventually pay for clearing up polluted soil.

 

A rule has been set up requiring those who cause pollution to pay for the treatment, but it is hard to implement, according to Liu Wenhua.

 

"The price of the soil rehabilitation should not be paid by farmers, because they are victims of the pollution," Liu said. "The government should aid public welfare by working to combat soil pollution."

 

Despite the government's policies and plans aimed at addressing environmental problems, it has long struggled to bring big polluting industries and growth-obsessed local governments to heel.

 

Zeng Sijian, chief of Guangdong's farmland fertilizer station, said the nation is facing grave soil pollution, including contamination of arable land by pesticides and chemical fertilizers, heavy metals, and pollution at mine and factory sites, which are hard to control.

 

Dabaoshan coal mine in Shaoguan City in Guangdong is an example. Starting in the 1970s, coal and waste water residue were not treated properly in the mining zone, which destroyed the local environment. Monitoring results in the early 2000s showed that the soil contained dangerous aluminum levels that were 44 times the national standard.

 

Zhang Bin, deputy head of the city's environmental protection bureau, confessed that despite years of efforts, pollution control has been hampered because of the seven-month monsoon in the southern province.

 

Illegal mining also continues rampantly despite government bans and rectification orders.

 

"Research on soil clean-up technology will be futile without curbing the pollution sources," added Liu.