Clear Lake - California
The coastal range of northern California offers fabled vineyards, soaring bald eagles and peregrine falcons and the state's largest freshwater body, Clear Lake. But Clear Lake and other waters in this region have a long-standing problem. Toxic mercury, draining from historic and modern mines, cycles through the watershed, threatening the Sacramento River and forcing officials to post fish consumption advisories at popular fishing spots.
Public lands in the upper watershed is dotted with mercury-laden waste, some from old mines that dug the mercury itself, and some from other types of mines of much more recent vintage. By the time the McLaughlin mine closed roughly 10 years after opening in 1985, it had produced 3.3 million ounces of gold and left a 750-foot pit extending for a mile filled with acidic water. Though the facility was closed according to plan, scientists say it is a significant source of mercury. Overall, an estimated 26 million pounds of mercury has made its way into the Sierra Nevada watershed, where much of it remains, threatening not only Clear Lake but more than half of California's water resources.
The Environmental Protection Agency reports that modern metal mining releases more mercury than any other industry. Yet, the 1872 Mining Law offers no effective standards for controlling mercury discharges and no program for cleanup.
- The Sierra Fund, Mining's Toxic Legacy: An Initiative to Address Mining Toxins in the Sierra Nevada, March 2008. (PDF)
- California State Water Resources Control Board, "First Year Results of Contaminant Monitoring Program show Mercury and PCB's Remain a Problem in Sport Fish in California Lakes," press release, May 6, 2009. (PDF)