Cadmium is used in batteries, electroplating for aircraft and in some paints and pigments.
But the soft bluish-white metal similar to zinc and mercury is actually toxic to humans.
So it was with some alarm that residents of Guangdong learned this month that over 120 different brands of rice – the staple food in the southern province – had been shown to contain dangerously high levels of the substance.
In high concentrations the metal attacks the kidneys and lungs, and makes bones brittle and prone to breaking. Some health organisations also classify cadmium as a carcinogen, meaning it can cause cancer.
China and the European Union both set the safe limit for cadmium in rice at 0.2 milligrams per kilogram of rice
But in one case cited this month, a sample of rice grown in Guangdong contained 1.12 mg per kg of cadmium. Many others – mostly grown in the neighbouring province of Hunan – were found to be carrying more than 0.6 mg per kg, according to a statement on Guangdong’s Food Safety Committee’s website on May 23.
“As of May 22 the Provincial Food Safety Committee has received rice sampling data from 10 cities. Eight cities including Guangzhou included failed batches,” it conceded.
One might be inclined to applaud the committee for its transparency: results arrive one day, they are made public the next.
But, unfortunately, it was not so.
News began leaking out that rice had failed cadmium tests in the city of Guangzhou earlier in the month but at that stage the authorities had refused to name the brands involved.
For a week Guangzhou’s residents had to live with the uncomfortable suspicion that some of the rice on the shelves might be contaminated. But they couldn’t tell which.
So consumers began to reject southern rice altogether, favouring rice from the north of China or imported brands from Thailand instead.
Visitors to Hong Kong began bringing rice home with them, raising concerns in the former British colony that there would be a run on rice supplies, just as there has been on baby formula in recent years.
In response Guangdong’s Food Safety Committee finally acted, publishing the names of the brands that had failed the test.
“What are they hiding?” asked one weibo user. “I can only guess that the truth is far worse than we imagine.”
If WiC has understood the figures correctly (they appear to have been released in a deliberately confusing manner) the situation looks like this: about 10% of the rice on sale in Guangdong appears to have been contaminated with cadmium.
Should we surprised? Perhaps not greatly given so much of the rice is sourced from Hunan. A study carried out by the Nanjing Agricultural University in 2011 found rice in Hunan and the Guangxi Zhuang Autonomous Region to be the country’s most contaminated.
Then, as now, the main culprit is industry. Cadmium is released into soil during the mining and smelting of gold, iron and zinc, while China is also a major producer of mobile phones, cameras and computers. The batteries of each require the metal. Cadmium is also contained in cheap fertilisers which local farmers use in liberal quantities.
Once soil is contaminated it is notoriously hard to clean up.
Perhaps that is why Xinhua’s suggestion for protecting oneself against contaminated food proves so depressing.
“Experts recommend that people should not consume food and drink from one particular region [of China] for long, instead they should diversify to lower the risk,” the state news agency advised.
As one wit on weibo put it: “At least that will make sure that everyone gets their fair share of cadmium.”
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