Nigeria's gold-mining state of Zamfara is already in the throes of the world's deadliest lead poisoning epidemic. And unless a clean-up starts quickly, the situation could get much worse.
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When artisanal mining took off in Nigeria's Zamfara state in 2009, no-one could have predicted the consequences. No-one knew the mine sites were riddled with deadly levels of toxic lead and no-one knew that in some communities hundreds of children would die.
The world's worst lead poisoning epidemic has claimed 400 young lives and left thousands more brain damaged and disabled.
More than three years on, seven of the eight affected villages have been remediated: contaminated topsoil has been replaced and sick children have been treated.
But when the clean-up began, the biggest village, Bagega, was last in line, and money ran out before the diggers arrived.
It really is an unprecedented epidemic, so to a certain extent we don't know what the long-term effects will be. Ivan Gayton, Médecins Sans Frontières
As a result Médecins Sans Frontières (MSF) estimates that up to 1,500 children still need treatment. But the charity is unable to offer life-saving chelation therapy while the village is still contaminated.
In 2012 the Nigerian government pledged around $4m to complete the clean-up of Zamfara state and put safer mining practises into effect - charities say that funding has been withheld and time is running out. Unless is it released within the next week, it will be too late to cleanse Bagega before the rainy season in May and children will be exposed to lead poisoning for another year.
The Nigerian government said it is "deeply concerned" and that "strategies have been drawn up" but aid agencies are not convinced.
MSF's Head of Mission in Nigeria, Ivan Gayton, told Channel 4 News the situation is more serious that ever: "As doctors we're faced with the suffering and dying of children, of patients of ours, and there's nothing we can do. Until the money is released for the remediation, we're helpless."
In the west, children with more than five micrograms per decilitre of blood would generally be admitted to hospital. In Zamfara State children with 300-400 micrograms per decilitre are being treated.
Ivan Gayton says the levels are staggering: "The kind of lead poisoning levels we're seeing here are absolutely unprecedented.
"The largest lead poisoning in modern history was in Kosovo in the 1990s, where we were talking a few hundred people with lead levels in the 50-200 categories. Here we're talking about thousands of people with lead levels in the multi-hundreds. It really is an unprecedented epidemic, so to a certain extent we don't know what the long-term effects will be."
Doctors do know that thousands of children who survive could suffer long-term mental consequences. Lead poisoning causes brain damage and lowers IQ, and there are scientific studies suggesting it could be linked to increased aggression.
Ivan Gayton said these long-term effects are a huge concern, given the political instability and violence in the region: "Just in case the world is wondering what we need here in northern Nigeria... A bunch of people who are not so intelligent and a little more aggressive? Probably not such a good idea."
No time to waste
Human Rights Watch (HRW) and the Nigerian Youth Climate Action Network have launched a social media campaign aimed at Nigerian President Goodluck Jonathan.
HRW's Jane Cohen told Channel 4 News time is running out for children in Zamfara: "By not releasing the promised funding for environmental clean up immediately, the government of Nigeria is sentencing more children to senseless death and permanent disability.
"Children in Zamfara cannot wait for another year for life saving medical treatment or to have their homes cleaned of lead contamination. Over the next year more children will die and more will face life long permanent disability from lead poisoning."
She added: "The government of Nigeria must step up and take responsibility for the health and well being of its people. Releasing money for environmental clean up-money that was promised in May-is a critical first step."