The oft repeated warnings of mercury in fish are revealed, in this article from the Wall Street Journal (subscription required) to be usually overwrought.
An excerpt.
“The Environmental Protection Agency recently issued 946 pages of new rules requiring that U.S. power plants sharply reduce their (already low) emissions of mercury and other air pollutants. EPA Administrator Lisa Jackson claims that while the regulations will cost electricity producers $10.9 billion annually, they will save 17,000 lives and generate up to $140 billion in health benefits.
“There is no factual basis for these assertions. To build its case against mercury, the EPA systematically ignored evidence and clinical studies that contradict its regulatory agenda, which is to punish hydrocarbon use.
“Mercury has always existed naturally in Earth's environment. A 2009 study found mercury deposits in Antarctic ice across 650,000 years. Mercury is found in air, water, rocks, soil and trees, which absorb it from the environment. This is why our bodies evolved with proteins and antioxidants that help protect us from this and other potential contaminants.
“How do America's coal-burning power plants fit into the picture? They emit an estimated 41-48 tons of mercury per year. But U.S. forest fires emit at least 44 tons per year; cremation of human remains discharges 26 tons; Chinese power plants eject 400 tons; and volcanoes, subsea vents, geysers and other sources spew out 9,000-10,000 additional tons per year.
“All these emissions enter the global atmospheric system and become part of the U.S. air mass. Since our power plants account for less than 0.5% of all the mercury in the air we breathe, eliminating every milligram of it will do nothing about the other 99.5% in our atmosphere.”