When mercury gets into waterways and wetlands, it binds with proteins in plants and animals and forms methylmercury, which can be fatal. One- fourth of the 16,500 acres of Cargill ponds the state and federal governments intend to restore as wetlands contain the mine's mercury. The highest mercury levels found, he said, were in the eggs of birds that nest in Cargill salt ponds near where the Guadalupe River enters the bay. "Pretty much consistently, birds nesting in the bay have more mercury in their eggs than birds outside the bay," said Steve Schwarzbach, biologist with the U.S. Nearly three-quarters of the black-crowned night heron's eggs, gathered in the Guadalupe watershed for a study, contained enough mercury to kill embryos. The endangered California clapper rail, a wetland bird whose population has shrunk to 1,200 worldwide, has a high rate of eggs that fail to hatch and more than half of those eggs contain harmful mercury levels. Among the affected species are black-necked stilts, avocets, snowy plovers and Caspian terns. Studies show mercury from the mine is killing bird embryos in the eggs and most likely killing fish hatchlings. "The mine is the single most significant source of mercury to the bay," said Tom Mumley, senior water resources control engineer at the San Francisco Bay Regional Water Quality Control Board in Oakland.Īlong with PCBs from power transformers, mercury is the bay's worst pollutant. Laws making owners of pollution sources responsible for cleanup mean the county, a local water agency and the city of San Jose, through which the highly toxic metal moves via the Guadalupe River, could all have to pay to stem the movement of mercury to the bay - and they could also be assessed additional millions of dollars for harm the mercury has done to wildlife, regulators say. This sign is posted on the shores of Almaden Lake in San Jose.īut until scientists recently conducted a widespread sampling of mercury contamination in the bay, they had no idea just how much of the mercury in the estuary originated with New Almaden.Īnd soon, local governments including Santa Clara County, which purchased part of the mine property for parkland in the 1970s, could find themselves on the hook for part of a multimillion-dollar cleanup effort as the state focuses on tough new requirements imposed by the federal Clean Water Act. After the ubiquitous PCBs, mercury is the second worst bay contaminant The park is the site of over 135 years of mining activities and former home to more than 1,800 miners and their families.ĬHRONICLE PHOTO BY MICHAEL MALONEY MICHAEL MALONEY Show More Show Less 8 of12 Warning signs are posted along the entire drainage system of the Quicksilver Mines - all the way out to and including the SF Bay. Sediments that contain mercury have deposited in some of the local reservoirs and streams and has polluted the bay. The SF Bay's single biggest source of toxic mercury comes from the Almaden Quicksilver County Park which was once the site of extensive quicksilver (mercury) mining. After a heavy rain storm, the river has measured mercury levels at 10 parts per million - 5 times higher than the rest of the bay. The mercury eventually makes it's way to the SF Bay more than 20 miles away poisoning the entire ecosystem along the way.Ħ of12 7 of12 The Guadalupe River runs through the center of downtown San Jose carrying deadly mercury from the Quicksilver Mines out to the bay. He is now keeping an extensive record of the chinook salmon which are now spawning in the river.ĬHRONICLE PHOTO BY MICHAEL MALONEY MICHAEL MALONEY Show More Show Less 5 of12 Old mine tailings containing hazardous mercury litter the hillsides above South San Jose. He was born and raised in San Jose and used to fish and play on the river when he was young. Tailings from this and the many other mines at the park are contaminating the bay with mercury.ĬHRONICLE PHOTO BY MICHAEL MALONEY MICHAEL MALONEY Show More Show Lessģ of12 4 of12 Roger Castillo, a self taught field biologist is one of the leading experts on the Guadalupe River. This is the remains of the April Mine shaft at Quicksilver County Park. PHOTO COURTESY OF THE COUNTY OF SANTA CLARA Show More Show Less 2 of12 ?MERCURYc-C-05DEC02-MT-MJM After the ubiquitous PCBs, mercury is the second worst bay contaminant The park is the site of over 135 years of mining activities and former home to more than 1,800 miners and their families. Ore cart and miners in Randol Shaft at the Almaden Quicksilver County Park.
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