Cadmium Rice Needs Costly Clean-up

Liu Xiangji, a rice mill operator in Hunan Province's You County, claims he hasn't been able to sleep at night since cadmium was detected in his mill's rice. "What is cadmium? I really don't know." Liu is perplexed because his mill removes husks, polishes the rice and bags it; nothing is added to the rice in the process. So he doesn't understand how rice could have become contaminated.

In contrast to many of China's other food safety incidents, there is no "black-hearted" behavior or clear culprits intentionally adding poisons in the "cadmium rice" incident. Instead, it stems from widespread pollution of the rice-growing environment due to both unchecked industrialization and abuse of agricultural chemicals by farmers.

The cadmium contamination is blamed largely on waste from mining and metal-smelting industries that is carried to fields by irrigation water, deposited in the soil and then absorbed by crops. Polluting industries are often shielded by the "umbrella" of local government. One scholar blamed "GDP supremacy" for the contamination. 

In October 2011, a scholar of China's Academy of Engineering warned that one-sixth of his country's cultivated land was contaminated with cadmium. No one paid much attention until 17 months later in May of this year when news media reported that a number of rice samples in Guangdong Province exceeded legal tolerances for cadmium, a lustrous white heavy metal that can cause kidney and skeletal disorders.

Caixin reports that cadmium contamination has been found in several different scientific studies and may have been known by grain management officials since 2002. The problems seem to be concentrated in Hunan Province, especially in central and eastern parts of the province--also China's most productive rice-growing region. Many consumers and traders are now shunning Hunan rice. Rice from neighboring Jiangxi and parts of Guangdong have tested positive as well.

Agriculture itself may bear a significant part of the blame. Abuse of chemical fertilizer and pesticides also has contributed to the cadmium problem. Phosphate fertilizer is a source of cadmium that is limited in Europe and North America. A Hunan Province agricultural expert said that Hunan's soil is highly acidic, a condition that makes rice plants more readily absorb cadmium. He blames the high acidity on excessive use of agricultural chemicals.

Reversing contamination of the soil is difficult--more difficult to deal with than air and water pollution. A Chinese Academy of Sciences Institute of Geographic Sciences expert estimated that it would take 3 to 5  years and 20,000 yuan per mu to clean up lightly-polluted soils. The total bill for cleaning up the soil was estimated at 6 trillion yuan (about $1 trillion).

Wen Tiejun, a well-known rural affairs scholar from Renmin University, is critical of the chemical-intensive methods used in Chinese agriculture. He has been promoting chemical-free production methods at a demonstration site in Hebei Province. Professor Wen says that crops need to be grown chemical-free for 3 to 5 years to detoxify the soil. This is needed to break what he calls the "vicious cycle" of chemical fertilizer use which degrades the natural fertility of soil, prompting even higher chemical applications. However, following Prof. Wen's prescription nationwide would require several years of low output, a non-starter for a country struggling to feed its population.

Some consumers are seeking out rice from northeastern China which has a reputation for being a relatively unspoiled environment. However, the northeast has been losing its rich black topsoil at an alarming rate. Moreover, Old Zhang, a Jilin Province farmer. worries that the increased dependence on chemical fertilizer is degrading the "vigor" of his soil. He observes that ten years ago he used to apply only 30 kg of fertilizer per mu but now applies 60 kg. And if fertilizer is not used, production will fall by half.

The vice director of the Chinese Academy of Agricultural Sciences soil institute worries that the land tenure system discourages soil conservation. "In a few years, you may not have this land any more, so why would you want to invest in conservation?" asks the scientist.