Illegal gold-mining camps in Ghana provide impoverished locals with a means to earn some much-needed cash -- but at a high environmental price. The mercury that small-scale miners use to purify gold not only threatens the miners' own health but also the health of whole communities, as mercury concentrations build up in waterways and fish. But local leaders still prefer the camps with thousands of illegal miners to large, corporate-run mines, which have legal rights to most of the ore deposits in the nation. The multinational mining companies employ few locals, bulldoze hills and trees, pollute groundwater, and destroy streams. The companies channel a small percentage of their profits toward community improvements such as schools, but not nearly enough to help tackle the nation's numerous social and environmental problems. Josh Harkinson reports from the goldfields of Ghana -- only on the Grist Magazine website.