A state agency is advising the public not to eat fish from several lakes and waterways in Santa Clara County due to high levels of mercury.
The recommendation from the California Environmental Protection Agency's Office of Environmental Health Hazard Assessment says that no fish should be consumed from Alamitos Creek, Almaden Lake, Almaden Reservoir, Calero Creek, Calero Reservoir, Guadalupe Creek, Guadalupe Reservoir, Guadalupe River, and associated percolation ponds.
The advisory is based on data collected through 2019 on fish caught at those locations.
"These water bodies are located in the Guadalupe River Watershed in Santa Clara County, which has a history of intensive mercury mining," the agency said. "The New Almaden Mining District, located in the Guadalupe River watershed, was North American's largest producing mercury mine, and mining waste continues to deposit mercury into the watershed."
The new recommendation updates one made in 1987 by adding Almaden Lake and Calero Creek.
The agency noted that "Calero, Almaden and Guadalupe Creeks flow northward from the Santa Cruz Mountains toward San Jose. Water from these creeks feeds the Guadalupe River, which flows through San Jose to San Francisco Bay. The reservoirs named in the advisory are located along the three creeks and the river."
Mercury, a naturally occurring metal that is released into the environment from mining and burning coal, "accumulates in fish in the form of methylmercury, which can damage the brain and nervous system, especially in developing children and fetuses," the OEHHA said.
Advisories for the Santa Clara County locations and more than 100 other OEHHA advisories about places where people catch and eat fish in California are available on OEHHA's Fish Advisories web page.