By Le Monde

From the air it looks like a huge lake, fed by many tributaries, but on the ground it turns out to be a murky expanse of water, in which no fish or algae can survive. The shore is coated with a black crust, so thick you can walk on it. Into this huge, 10 sq km tailings pond nearby factories discharge water loaded with chemicals used to process the 17 most sought after minerals in the world, collectively known as rare earths.

The town of Baotou, in Inner Mongolia, is the largest Chinese source of these strategic elements, essential to advanced technology, from smartphones to GPS receivers, but also to wind farms and, above all, electric cars. The minerals are mined at Bayan Obo, 120km farther north, then brought to Baotou for processing.

The concentration of rare earths in the ore is very low, so they must be separated and purified, using hydro-metallurgical techniques and acid baths. China accounts for 97% of global output of these precious substances, with two-thirds produced in Baotou.

The foul waters of the tailings pond contain all sorts of toxic chemicals, but also radioactive elements such as thorium which, if ingested, cause cancers of the pancreas and lungs, and leukaemia. “Before the factories were built, there were just fields here as far as the eye can see. In the place of this radioactive sludge, there were watermelons, aubergines and tomatoes,” says Li Guirong with a sigh.

It was in 1958 – when he was 10 – that a state-owned concern, the Baotou Iron and Steel company (Baogang), started producing rare-earth minerals. The lake appeared at that time. “To begin with we didn’t notice the pollution it was causing. How could we have known?” As secretary general of the local branch of the Communist party, he is one of the few residents who dares to speak out.

Towards the end of the 1980s, Li explains, crops in nearby villages started to fail: “Plants grew badly. They would flower all right, but sometimes there was no fruit or they were small or smelt awful.” Ten years later the villagers had to accept that vegetables simply would not grow any longer. In the village of Xinguang Sancun – much as in all those near the Baotou factories – farmers let some fields run wild and stopped planting anything but wheat and corn.

A study by the municipal environmental protection agency showed that rare-earth minerals were the source of their problems. The minerals themselves caused pollution, but also the dozens of new factories that had sprung up around the processing facilities and a fossil-fuel power station feeding Baotou’s new industrial fabric. Residents of what was now known as the “rare-earth capital of the world” were inhaling solvent vapour, particularly sulphuric acid, as well as coal dust, clearly visible in the air between houses.

Read more from The Guardian: http://www.guardian.co.uk/environment/2012/aug/07/china-rare-earth-village-pollution