August 20, 2009

Mercury Pollution Widespread In US Streams

A new federal study suggests that fish cannot escape mercury pollution.

The study, conducted by the U.S. Geological Survey, tested fish from nearly 300 streams across the country for traces of mercury, and found that every sampled fish contained the substance.

Although all the fish had traces of mercury, only a quarter had levels considered unsafe for human consumption.

Over a thousand fish were tested from 1998 to 2005 for the study.

"This science sends a clear message that our country must continue to confront pollution, restore our nation's waterways, and protect the public from potential health dangers," said Interior Secretary Ken Salazar said in a statement.

Mercury can cause learning disabilities in young children, and can also damage the nervous system if consumed.

According to researchers, the majority of mercury found in the streams was from coal-fired plant emissions.  The mercury released from smokestacks finds its way into streams due to rainfall.  Once in the waterways, the mercury is converted into methylmercury, which allows it to work its way through the food chain.

The highest levels of mercury were found in fish that lived in blackwater streams along the coasts of the Carolinas, Georgia, Florida and Louisiana.  Bacteria in these regions help the conversion process.

The concentration was also high in largemouth bass from the North Fork of the Edisto River near Fairview Crossroads, S.C.

"Unfortunately, it's the case that almost any fish you test will have mercury now," said Andrew Rypel, a post-doctoral researcher at the University of Mississippi.

According to Rypel, research has shown mercury in fish from Alaska, Canada, and even fish that live deep in the ocean.

The most contaminated sample came from smallmouth bass collected from the Carson River at Dayton, Nev., an area that contains a number of gold mines.

"Some ecosystems are more sensitive than others," Barbara Scudder, the lead USGS scientist on the study, told the AP.

All states but Alaska and Wyoming have issued fish-consumption warnings due to mercury contamination.

"This is showing that the problem is much more widespread," said Sonya Lunder, a senior analyst for the Environmental Working Group

"If you are living in an area that doesn't have a mercury advisory, you should use caution," she said.

The Obama administration said it would begin crafting regulations for mercury emissions earlier this year.  A previous plan drafted by the Bush administration was thrown out by a federal appeals court.

The Bush plan would have allowed companies to buy and sell pollutions credits, similar to a greenhouse gas emissions bill that was passed in the US House of Representatives in June.

The US Environmental Protection Agency has also proposed new regulations to lower mercury emissions from cement plants.


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