A coalition of tribal, conservation and fisheries groups is considering its legal options in the fight to uphold a Californian law regulating suction dredge mining, following a state judge's ruling that the California law is preempted by federal law.
The ruling could end the moratorium on suction dredge mining, enacted in 2009.
California's Supreme Court is also considering whether to take up the legal issues surrounding the state law, which has been designed to reduce mercury pollution and damage to wildlife, waterways and cultural resources caused due to the destructive mining.
Center for Biological Diversity toxics and endangered species campaign director Jonathan Evans said: "This decision has grave implications for Californians' ability to protect our own waterways, wildlife and cultural resources from destructive mining.
"Our citizens have the right to safeguard the health of their families and the waterways we all depend on from a clearly known harm."
Suction dredge mining uses machines to vacuum up gravel and sand from streams and river bottoms in search of gold and is said to suspend toxic mercury, sediment and heavy metals and harm state water supplies.
In-stream suction dredge mining was prohibited by Californian law until the state had developed regulations to pay for the programme and protect water quality, wildlife and cultural resources.
Scientists and government agencies have already documented the harm caused by such mining, the coalition said.
Suction dredge mining is said to significantly impact water quality and wildlife due to mercury pollution, prompting the Environmental Protection Agency and State Water Resources Control Board to urge for a complete ban on it.
Causing a threat to important cultural resources and sensitive wildlife species, suction dredge mining also destroys the sensitive habitats of important and imperiled wildlife.
Represented by Lynne Saxton of Saxton & Associates, the coalition includes the Center for Biological Diversity, the Karuk tribe, Pacific Coast Federation of Fishermen's Associations, Institute for Fisheries Resources, Friends of the River, California Sportfishing Protection Alliance, Foothills Anglers Association, North Fork American River Alliance, Upper American River Foundation, Central Sierra Environmental Resource Center, Environmental Law Foundation and Klamath Riverkeeper.