US fish have high mercury levels

High mercury levels in fish

Here's some news to put you off your fish supper; a report from the Environmental Protection Agency (EPA) has said that nearly half of freshwater lakes and reservoirs in the US, contain fish with "potentially harmful levels of the toxic metal mercury."

It wasn't just mercury found in fish stocks; high levels of polychlorinated biphenyls (PCBs) or pesticides were also found in fish over the three year study. The EPA said that 49 percent of those lakes and reservoirs studied, mercury concentrations exceeded levels that are safe for people eating average amounts of fish.

"EPA is aggressively tackling the issues the report highlights," Peter Silva, assistant administrator for the EPA's office of water, said in a statement. "Before the results were even finalized, the agency initiated efforts to further reduce toxic mercury pollution and strengthen enforcement of the Clean Water Act."

The danger of mercury

It is believed that the high levels of mercury comes mostly from burning coal and other fossil fuels. Once the mercury emissions are in the atmosphere, they enter lakes and rivers through precipitation. Forests and wetlands then provide conditions that enhance the conversion of mercury into methylmercury, a highly toxic form that accumulates in fish. High levels of mercury have been found to damage the nervous system and cause learning disabilities in developing fetuses and young children.

While only 17 percent of fish stocks were found with PCBs in them, they can still cause cancer and other illnesses. It is a testament to the lethality of PCBs, that despite them being banned in the late 70s, when they were used as coolants and lubricants, they they can still haunt us today.

The report was also bad news for the Southern states with North Carolina holding the distinction of having the highest levels of contamination in the country. South Carolina, Georgia, Florida and Louisiana rounded out the list of the most contaminated states.

More disturbing, every fish sampled taken from the 291 river and streams were found to contain levels of mercury, though only a quarter had dangerous levels. Not quite the side dish to fish that tartar sauce is, is it?

Download the full EPA report here - http://www.epa.gov/waterscience/fish/study/data/finalreport.pdf

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