U.S. Mercury Alerts
U.S. Geological Survey map; data from EPA
American industry releases mercury into the environment, mostly as emissions from the burning of coal and petroleum. Other sources are old mines and waste incineration. Here's an article about the geology of mercury, and also a list of mercury geo-links for more information.
Mercury in the water tends to accumulate up the food chain, from microorganisms to food species to fish and water mammals. Where levels of mercury in the water become a concern, the authorities issue a health advisory that recommends limits on the amount of fish you should eat—especially if you're pregnant or an infant.
