Mercury is an efficient magnet for gold. The early California miners routinely lined their sluices with the silvery globules to amalgamate the precious metal. Up to 10 percent of an estimated 65,000 tons of mercury extracted from the Coast Range between 1850 and 1920 was lost to streams in the Coast and Sierra mountains. Modern gold miners working suction dredges still find pockets of the Argonauts' quicksilver lodged deep in the "guts" of rivers.

Fish advisories due to mercury contamination
San Francisco Bay/Delta system
Species Bass: Striped - larger than 27 inches Bass: Striped - larger than 35 inches Shark: Larger than 24 inches All fish except anchovy, herring, salmon, smelt	Advisory No consumption: Populations at risk (1) No consumption: All consumers No consumption: Populations at risk Restricted consumption (2): All consumers
Santa Clara County (3), Alamitos Creek, Alamden Reservoir, Calero Reservoir, Guadalupe Creek, Guadalupe River, Guadalupe Reservoir
Species All fish	Advisory No consumption: All consumers
Napa County: Lake Berryessa
Species All fish Bass: Largemouth, smallmouth Catfish: Channel, white Trout: Rainbow	Advisory No consumption: Populations at risk Restricted consumption: All consumers
Solano County: Lake Herman
Species Bass: Largemouth	Advisory Restricted consumption: All consumers
Lake County: Clear Lake
Species All fish Bass: Largemouth Blackfish: Sacramento Catfish: Brown, bullhead, channel, white Crappie: Black Hitch	Advisory No consumption: Populations at risk Restricted consumption: All consumers
San Luis Obispo County: Lake Nacimiento
Species Bass: Largemouth Bass: Largemouth	Advisory No consumption: Populations at risk Restricted consumption: All consumers
(1) Populations at risk: Children, pregnant women and women of child-bearing age. (2) Restricted consumption: Quantity and frequency should be restricted by indicated population to no more than one meal per month. (3) All Santa Clara County locations include associated percolation ponds.

Mercury in the ecosystem Mercury in aquatic environments takes on a vicious life of its own. Bacteria converts the metal into the more toxic methyl-mercury, which can be taken up by insects, the fish that eat the invertebrates and humans who eat the fish. Mercury's concentration increases at each level up the food chain in a process known as biological magnification.
	Health effects of mercury Deteriorates the nervous system Impairs hearing, speech, vision and gait Causes involuntary muscle movements Corrodes skin and mucous membranes Causes chewing and swallowing to become difficult

Recovering mercury The mercury that stuck to the gold was removed and recovered by heating the amalgam. The quicksilver changed from a solid to a gas in the furnace. Upon cooling, the mecury vapor coverted to liquid for reuse.
	1. The amalgam of gold and mercury was placed in the furnace and heated. 2. Mercury turns to gas at a lower temperature than gold, so the vapor would be composed of mercury. 3. The mercury vapor was then cooled further down the pipe into liquid mercury.