The quickest way to separate gold from rock, Sadio Camara says, is with a drop of mercury. She empties a dime-sized packet of the silvery liquid into a plastic bucket of muddy sediment outside her home in southeastern Senegal. With bare hands and no mask, she swirls the mixture as her children look on. “I know mercury isn’t good for your health — that’s why I don’t drink the water it comes into contact with,” she said. “I only process small amounts of gold, so there’s no danger.” But even small-scale exposure can carry serious risks.Across West Africa, mercury — a potent neurotoxin — remains the dominant method for ... (full story)