BEIJING (Caixin Online) — As much as 10% of China’s rice may be tainted by poisonous cadmium, a heavy metal discharged in mine and industrial sewage that makes its way into rice paddies, according to agricultural researchers at a major university.

Much of this poisoned rice is consumed by farm families or sold in areas of the nation’s food market beyond the reach of government safety regulators.

Following the lead of research conducted by scientists at Nanjing Agricultural University’s agricultural resource and environment institute, a Caixin probe found several dozen farmers in the village of Sidi in southern China’s Guangxi Autonomous Region have been troubled by a strange weakness of the legs for decades.

Health officials have declined to link the feeble-leg condition to pollution, but similar conditions have been found among farmers in Zhejiang province that the Nanjing scientists blamed on high levels of cadmium in the rice local families eat almost daily.

Rice is a staple food for 65% of the population in China, where annual rice farm output is about 200 million tons.

Sidi’s rice paddies have been polluted by sewage from a nearby lead and zinc mine.

The Nanjing researchers, led by farm scientist Pan Genxing, took 91 samples from markets in six regions nationwide in 2007 and found elevated cadmium levels in 10% of the commercially sold rice.

The research attracted little attention after its publication three years ago. Pan’s team followed up with another survey in 2008 focusing on several southern provinces.

They found 63 samples from markets in Jiangxi, Hunan and Guangdong provinces contained elevated cadmium levels in 60% of the rice, suggesting the problem is far more serious in the south than northern China.

Chen Tongbin, a research fellow at the China Academy of Sciences specializing in soil pollution and remediation, estimates heavy metals have polluted 10% of China’s farmland. Leading the list of poisons are cadmium and arsenic.

To date, none of China’s hospitals have officially recognized the weak-leg condition common in some communities. But agriculture scientists have reluctantly called the phenomenon an early symptom of itai-itai disease, the name given to cadmium poisoning suffered by many in Japan after an environmental disaster in the 1970s that led to severe spine and joint pain, as well as brittle bones.

Some Chinese farmers are aware that eating the tainted rice they grow can make them sick, but they can’t afford the cleaner rice sold in markets.

Many other farm families have been kept in the dark about the heavy-metal hazards due to a void in government regulations in plantation and a lack of information about pollution risks, so they continue eating toxic rice. Caixin’s investigation found some of this contaminated rice enters local commercial markets as well. See this report at Caixin Online.