And this story in the San Francisco Chronicle:
Researchers have found toxic mercury in fish caught at a reservoir that provides water to 2.5 million people in the San Francisco Bay area. Authorities say largemouth bass taken from Lower Crystal Springs Reservoir in San Mateo County had some of the highest mercury levels in the state. However, the contamination doesn't indicate that the water itself is unsafe. The mercury was detected by researchers at the San Francisco Estuary Institute, who sampled sport fish at nearly 300 California lakes for mercury and other contaminants. The results, released last month, found that 21 percent of the lakes had at least one fish species with a mercury level considered unsafe to eat by children.