Gold Mining Is Poisoning the Planet With Mercury

Jeovane de Jesus Aguiar was knee-deep in mud in the 100-yard gash he had cut into the Amazon rainforest, filtering brown water out of a pan, when he found the small, shiny flake he was looking for: a mixture of gold and mercury.

Mr. Aguiar had drizzled liquid mercury into the ground in his makeshift gold mine on the eastern edge of the small South American nation of Suriname, just as he had every few days.

The toxic element mixes with gold dust and forms an amalgam he can pluck out of the…