November 2012 | Volume 120 | Issue 11
On the Cover | Focus
Mercury amalgamation has been used for centuries to process precious metals. Today, artisanal and small-scale gold mining is the world’s second greatest source of atmospheric mercury pollution after coal combustion. Other mercury waste ends up in soils and waterways. And with gold prices now exceeding US$1,600 per ounce, artisanal and small-scale gold mining is on the rise along with its mercury problem.
The Elwha River’s two hydroelectric dams have become stars of a four-decade-long saga, culminating in the complete removal of the lower Elwha Dam this past summer, with the taller Glines Canyon Dam scheduled for full removal by summer 2013. Tearing down dams releases mass quantities of pent-up sediment and sometimes contaminants, but over the long term it restores ecosystems. As the Elwha River ecosystem begins a dramatic transformation, the biggest dam removal in history is being touted as a model for future dam breaches.