Mercury in Fish
Every fish sampled across the western United States contained mercury, suggesting that industrial pollution generated around the world is likely responsible. The survey of 2,707 fish randomly collected from 626 rivers in 12 states represents the biggest regional sampling yet of mercury in fish in the West.
The findings by scientists from the EPA and Oregon State University were reported in this month's issue of the journal Environmental Science & Technology and came out of an EPA survey of various environmental factors in rivers conducted between 2000 and 2004.
Though the survey found some fish with elevated mercury levels, suggesting a local source such as an old mercury mine, most levels were low, in line with canned tuna found in grocery stores.
While generally below levels considered unsafe for people to eat from time to time, the mercury could pose a danger to fish and wildlife that depend on fish for their diet. Levels were generally higher in bass, walleye and pike, than in insect-eating fish, such as trout.
Elevated mercury levels have been linked to learning disabilities and developmental delays in children and to heart, nervous system and kidney damage in adults. Out of concern for the health effects, several states and the federal government have taken steps to cap mercury emissions.
It has long been understood that industrial emissions, such as coal-fired power plants, are responsible for some percentage of the mercury found in fish. About two thirds of the mercury circulating in the atmosphere is generally considered to come from industrial or human sources, with the rest from things like volcanoes and other geologic sources.
January 24, 2007 6:37 AM | Category: Chemicals, Fish