TANG DONGHUA, a wiry 47-year-old farmer wearing a Greenpeace T-shirt, smokes a cigarette and gesticulates towards his paddy fields in the hills of southern Hunan province. The leaves of his rice plants poke about a foot above water. Mr Tang says he expects to harvest about one tonne of rice from his plot of a third of a hectare (0.8 acres) near the small village of Shiqiao. There is just one problem: the crop will be poisoned.

Egrets and damselflies chomp lazily on fish and insects in the humid valley below the paddy fields. But just beyond this rural scene lurks something discordant. Mr Tang points to a chimney around 2km away that belches forth white smoke. It belongs to the smelting plant which he blames for bringing pollution into the valley. Cadmium is released during the smelting of ores of iron, lead and copper. It is a heavy metal. If ingested, the liver and kidneys cannot get rid of it from the body, so it accumulates, causing joint and bone disease and, sometimes, cancer.Lat

Hunan province is the country’s largest producer of rice—and of cadmium. The local environmental-protection agency took samples of Mr Tang’s rice this year and found it contained 50% more cadmium than allowed under Chinese law (whose limits are close to international norms). Yet there are no limits on planting rice in polluted areas in the region, so Mr Tang and his neighbours sell their tainted rice to the local milling company which distributes it throughout southern China. Mr Tang has sued the smelter for polluting his land—a brave act in China, where courts regularly rule in favour of well-connected businesses. His is an extreme case of soil contamination, one of the largest and most neglected problems in the country.