Abandoned mercury mines throughout central California's rugged coastal mountains are polluting the state's major waterways, rendering fish unsafe to eat and risking the health of at least 100,000 impoverished people.
But an Associated Press investigation found that the federal government has tried to clean up fewer than a dozen of the hundreds of mines — and most cleanups have failed to stem the contamination.
Although the mining ceased decades ago, records and interviews show the vast majority of sites have not even been studied to assess the pollution, let alone been touched.
"Tens of thousands of subsistence anglers and their (families) are consuming greater than 10 times the U.S. EPA recommended dose of mercury, which puts them at immediate risk of neurological and other harm," Shilling said.
Mercury from mine waste travels up the food chain through bacteria, which converts it to methylmercury — a potent toxin that can permanently damage the brain and nervous system, especially in fetuses and children.
The federal government calls methylmercury one of the nation's most serious hazardous waste problems, and the Centers for Disease Control and Prevention says it is a possible carcinogen.
"Mercury tops the list as the most harmful invisible pollutant in the (state's) watershed," said Sejal Choksi of San Francisco Baykeeper, an environmental watchdog group for the bay. "It has such widespread impacts, and the regulatory agencies are just throwing up their hands."
In the 19th and 20th centuries, California produced up to 90 percent of the mercury in the U.S. and more than 220 million pounds of quicksilver were shipped around the world for gold mining, military munitions and thermometers. Much of the liquid mercury was sent to Sierra Nevada gold mines, where miners spilled tons of it into streams and soil to extract the precious ore.
"There's probably a water body near everybody in the state that has significant mercury contamination," said Dr. Rick Kreutzer, chief of the state Department of Public Health's Division of Environmental and Occupational Disease Control.
The CDC says high levels of mercury can cause brain damage and mental retardation in children when passed from mother to fetus. Brown's son, Tiyal, has been diagnosed with autism. The CDC has found no link between mercury and autism, but agency spokesperson Dagny Olivares said in an e-mail, "Additional information is needed to fully evaluate the potential health threats."
At most abandoned mercury mines, especially ones in remote places, nothing gets done at all.
A separate cluster of derelict mercury mines near San Jose has been called the largest source of the toxin in the San Francisco Bay's south end, where warning signs warn fishermen of the "poisonous mercury" polluting the water.
A solution to California's mercury pollution is nowhere near at hand, state and federal regulators say.
"It took a hundred years to occur," said the EPA's Meer. "And it may take a hundred years or more to solve."
Source: AP News