By Christian Purefoy, CNN

Yangalama, Northern Nigeria (CNN) -- Standing in the graveyard Rabiu Mohammed prays silently in a cemetery that has filled quickly with small tell-tale mounds of earth.

It's hard to imagine as many freshly dug little graves side by side in a place that's not a war zone -- as there are right now in the Nigerian village of Yangalama.

Rabiu lost two children. At least 68 other boys and girls are buried alongside them, or one-third of the village's children.

They began dying in January. For months the cause was a mystery, until local authorities, disturbed by the strange manner of the deaths, called in international medical agencies.

By March it was clear the problem was massive and widespread lead poisoning.

"These are months of fear and trepidation for this village," Rabiu explained.

"You have either lost a child or your brother, or a friend, or someone close to you has lost a child."

So far the U.S. Centers for Disease Control (CDC) estimates 163 people have died of lead poisoning across the region -- 111 of them children.

Unwittingly, the villagers brought the lead into their own homes. Searching for gold in nearby mines, they took the metal ore home where it was smashed and processed in the village. The lead and other waste metals are released and discarded.

Unofficial mining is illegal but this region in northern Nigeria is rich in minerals and many people depend on it for their livelihoods.

But it seems this time miners struck a particularly toxic seam of metal ore.

Young children, laying in the dust and sleeping on the bags used to carry the metal ore, are the most susceptible.

The CDC is calling the scale of the problem "unprecedented in the CDC's work with lead poisoning worldwide."

Medical authorities have since moved many of the most urgent cases to a nearby hospital, where Medecins Sans Frontieres and the World Health Organization are providing treatment.

More than 50 children are being treated with a medicine that binds itself to lead in the bloodstream so it can be released as urine.

They are expecting 50 more children in the next few weeks.

"[With] some of the initial samples that were taken and sent off for testing in Europe we're finding some levels over 300, which is just quite shocking for people who would normally treat levels under 10," explains Dr. Jenny McKinsey, an MSF medical officer.

But mining in the region continues and many people remain in some of the worst affected villages.

The Blacksmith Institute -- a global leader in pollution clean-up operations -- is trying to remove the highly toxic topsoil in some of the villages. But with the onset of the rainy season it's a race against time, as the rains make many of the roads impassable and spread the lead throughout the area.

"We are moving quickly to avert a catastrophe as the rainy season approaches," they warn in a statement.

But at the hospital, the doctors remain cautiously optimistic. "Yes, we're hoping to stop the acute poisoning," explained McKinsey.

"As for how low we can get the levels no-one seems to know. We've been speaking with specialist toxicologists around the world, getting their opinions and they're all very interested and waiting to see what will happen."

But as Rabiu Mohammed closes the wire gate to the graveyard and takes the short walk home -- this place is poisoned forever.

http://www.cnn.com/2010/WORLD/africa/06/10/nigeria.poisons/index.html?hpt=T3