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History of Mercury in the Guadalupe Watershed

History of mercury timelineThe 170-square mile Guadalupe River watershed has six reservoirs, more than 80 miles of streams and rivers and is one of the area’s biggest sources of mercury contamination.

Mercury in the Guadalupe Watershed can trace its roots to the Gold Rush of the 1800s. Mercury was essential to the process of separating gold from ore and plenty of it could be found in the hills above San Jose.

The New Almaden Mines became the largest mercury mine in North America and work there would ultimately seep – according to the State Water Resources Control Board – an estimated 6,500 tons of mercury into the local systems of creeks and rivers between 1850 and 1920.