Heavy metals in foods: more trouble for China

We've spoken on several occasions about heavy metal contamination of herbal products, especially in light of this highly-cited JAMA paper. Part of the problem is that plants will bioaccumulate heavy metas, especially when grown in soils rich in these natural and industrial products.

The Wall Street Journal reported Monday that the Chinese are having issues with foods grown in "hot spot" soils such as those on former industrial sites or subjected to mining runoff (free full-length article reprinted at Moneyweb)

Ms. Lai, along with 57 other villagers, was eventually diagnosed with high levels of cadmium, a heavy metal that can cause kidney disease and softening of the bones. Runoff from the factory -- which the government tore down in 2004 -- had contaminated the farmland and entered the food supply. A Chinese government report found that rice grown in the village contained 20 times the permitted level of cadmium.

Apparently, this issue has been well-appreciated by Chinese scientists:

Chinese academics have written about such sites in more than a dozen studies over the past two years in Chinese and international scientific journals. In a study published earlier this year, researchers at the Guangdong Institute of Ecology found excessive levels of cadmium and mercury in Chinese cabbage grown in Foshan, a major manufacturing center in southern China. Last year, researchers at Lanzhou University published research showing that vegetables at four sites near the mining and smelting city of Baiyin in the Northwestern Gansu province contained hazardous levels of cadmium, lead and copper. A study of crops grown in the central city of Chongqing found excessive lead and cadmium levels in vegetables at 20 sites.

One of the more interesting points of the article is just how persistent metals are in the environment once they are present:

Last year, a group of Chinese scientists published a study that found the soil and vegetables around an abandoned lead and zinc mine a few hours outside of Shanghai was contaminated with heavy metals. It's not clear when the mine was in operation, but the local environmental protection bureau says that historical records indicated it was in use during the Qing dynasty, which ended in 1911. Slag that the miners had excavated from the mountain was left in piles near farmland, allowing rain to wash the metals into nearby fields.

With all of the ongoing concerns about Chinese-sourced goods, this story points to yet another threat to China's place in the global economy. But lost in all of the global discussions and concerns about Chinese food exports are the real harms and risks to the Chinese people themselves. The real tragedy here is the inability of a country to protect its own people.