Injecting an industrial metal back into the ground could prove a boon for farmers and miners alike.
The metal is zinc. Used mostly to reduce corrosion in iron and steel, zinc also is needed in trace amounts to keep humans and plants healthy. Without it in their diets, people are prone to diarrhea, pneumonia and malaria, and crops are stunted. The trouble is that farmland in South Asia, sub-Saharan Africa and Latin America is increasingly zinc deficient, leading to more than 450 000 deaths annually of children under age five, a 2008 study in The Lancet showed.
