Mercury Bioaccumulation in the
Cache Creek Watershed, California - A Local, Regional and Global-Scale Problem
A Story Map of
Long-Term Impacts of Mercury Mining
and the use of
Mercury for Gold Mining in California
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3 million to 8 million kilograms of mercury was lost to the environment through this mining process
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That mercury is transported downstream through seasonal erosional processes in addition to evaporation, atmospheric deposition and transport by species that have accumulated mercury in their tissues (Alpers et al., 2008; UNEP, 2013).
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Mine sites are point sources for ongoing mercury transport, bioaccumulation and biomagnification
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Mercury mining began in California in 1846
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California did not become a state until 1850, so there were no environmental protection regulations (Krieger, 2015).
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Mercury is used for Gold Mining as it has the ability to pull other metals to itself - Amalgamation
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The Federal Mining Act (Law) of 1872 greatly encouraged the expansion of mercury exploration and mine claims
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The law was created to ‘foster extractive industry in the western United States’ with an underlying goal of gaining control over the land during the westward expansion of colonization of North America (Clark, 2016).
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The Coast Range of California has some of the largest mercury deposits in the world!
Mercury that was mined in the Coast Range was used at the Sierra Nevada and Klamath-Trinity Mountains' gold mines.
Miners blasted valley walls with water to get to the gold deposits in the sediment. That sediment was then pushed through sluices with mercury to amalgamate the gold with the mercury.
Hydrogeologic Provinces for California based upon established groundwater basins and watershed polygons.
By: Tyler Johnson and Kennith Balits, 2006
Locations of Mercury and Gold Mines
in
California
Map: Alpers et al., 2005.
A comparison of the maps to the right reveals the result of mercury mining and the use of mercury for gold mining in California's watershed. Those areas with watersheds, waterbodies and streams on the Clean Water Act's 303d list for mercury contamination are in the same areas as those with mercury and gold mines.
Watersheds, Waterbodies and Streams on the Clean Water Act's 303d List for Mercury Contamination
Locations of Mercury and Gold Mines
in
California
Map: Alpers et al., 2005.
The Cache Creek Watershed
Provides an Important Case Study
of
Mercury Bioaccumulation and Biomagnification.
Go to Ecosystem Services Impacts for that story map
The Cache Creek Watershed is located northeast of San Francisco, drains to the Sacramento river and onward to the San Francisco Bay Delta Estuary
Mercury mines in the Cache Creek Watershed are important point sources for mercury transport, bioaccumulation and biomagnification.
Fisheries in the Cache Creek Watershed are extremely important for:
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Subsistence, low-income residents and wildlife as a major protein source.
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Economic support from sport fishing and recreation
Go to
to see impacts of mercury mining and the use of mercury for gold mining in the Cache Creek Watershed
Sources for this page:
Alpers, Charles N., Collin Eagels-Smith, Chris Foe, Susan Klasing, Mark Marvin-DiPasquale, Darell Slotten, and Lisamarie Windham-Myers. 2008. “Sacramento-San Joaquin Delta Regional Ecosystem Restoration Implementation Plan.” US Geological Survey, 62.
Alpers, Charles N., Michael P. Hunerlach, Jason T. May, and Roger L. Hothem. 2005. “Mercury Contamination from Historical Gold Mining in California.” USGS Publications - Factsheet (blog). 2005.
Capay Valley Vision. 2017. “Capay Valley Historical Timeline.” Capay Valley Vision (blog). 2017.
Clark, Chris. 2016. “Court: State Can Limit Gold Mining Despite 19th Century Law.” KCET, 2016, sec. Redefine Mining. https://www.kcet.org/redefine/court-state-can-limit-gold-mining-despite-19th-century-law.
Kamman Hydrology & Engineering, Inc. 2010. “Watershed-Based Assessment of Hydrologic and Geomorphic Conditions in Cache Creek through Capay Valley Yolo County, California.” Technical. http://yolorcd.org/documents/cache_creek_geomorphology_assessment.pdf.
Krieger, Dan. 2015. “California’s Statehood Debate Foreshadowed the American Civil War.” San Luis Obispo Tribune, 2015, Special edition, sec. Times Past.
Sacramento River Watershed Program. 2010. “The Sacramento River Basin Westside Sub-Region: Cache Creek Watershed.” A Roadmap to Watershed Management. California Water Boards.
State of California. 2017. “California State Water Resources Control Board.” Government. Ca.gov (blog). 2017.
State Water Resources Control Board. 2017. “Chapter 27, California Code of Regulations, Title 23.” https://www.waterboards.ca.gov/laws_regulations/docs/wrregs.pdf.