WASHINGTON - A landmark study by scientists from the U.S. Geological Survey (USGS) <http://www.eenews.net/public/25/10743/features/documents/2009/05/01/document_gw_03.pdf>
 and universities in the U.S. and Australia has, for the first time,
documented how escalating mercury-laden air emissions, chiefly from
coal-fired electrical power plants in Asia, are being transformed into
methylmercury, a potent neurotoxin that is increasingly polluting the
North Pacific Ocean and contaminating tuna, swordfish and other popular
seafood.  
 
The study, published May 1 in Global Biogeochemical Cycles <http://www.agu.org/pubs/crossref/2009/2008GB003425.shtml>
, a scientific journal of the American Geophysical Union, predicts a 50
percent spike in the Pacific’s mercury level by the year 2050 if
mercury emissions from power plants increase according to current
projections.   
 
Mercury levels in fish risk children’s health

Mercury exposure is especially dangerous to the fetus, newborn infants
and young children during critical windows when the brain and other
organs are rapidly developing.  
 
Researchers have suspected for some time that emissions from coal-fired
power plants in energy-hungry, rapidly industrializing China and India
were a major environmental threat:  according to the study, over the
past two decades, emissions during the combustion of coal, which
contains elemental mercury, have declined in North America and Europe,
but “increased substantially” in East Asia and India. But exactly how
airborne mercury from Asia has been entering deep ocean fish caught
thousands of miles away has not been understood until now.
 
“Mercury researchers typically look skyward to find a mercury source
from the atmosphere due to emissions from land-based combustion
facilities,” USGS scientist and coauthor David Krabbenhoft said in a
statement.  “In this study, however, the pathway of the mercury was a
little different. Instead, it appears the recent mercury enrichment of
the sampled Pacific Ocean waters is caused by emissions originating
from fallout near the Asian coasts. The mercury-enriched waters then
enter a long-range eastward transport by large ocean circulation
currents.”  
 
In mid-depth ocean, the study showed, decomposing algae interact with
mercury to form lethal methylmercury that enters the food chain,
eventually contaminating tuna and other food fish.
 
EPA chief calls fish and mercury “major health threat”

Environmental Protection Agency (EPA) Administrator Lisa Jackson <http://yosemite.epa.gov/opa/admpress.nsf/3881d4aaa0b85257359003f5348/577aada113bdd840852575a900660baf!OpenDocument>
 declared that the study “shines new light on a major health threat to
Americans and people all across the world” and signaled that the Obama
administration intends to embark on new diplomatic efforts to persuade
the Asian nations  “to significantly cut mercury pollution in the years
ahead and protect the health of millions of people.”
 
The implications of the mercury cycle for human health are grave.
 According to the USGS, over 90 percent of human methylmercury exposure
in the U.S <http://toxics.usgs.gov/highlights/pacific_mercury.html>
. can be attributed to consumption of ocean fish and shellfish. Pacific
tuna consumption accounts for 40 percent of Americans’ exposure.
 
Studies show that mercury exposure can alter brain development in the
fetus, leading to learning problems, reduced performance on
intelligence tests and other health problems later in life.
 
FDA under pressure to promote low-mercury fish

EPA’s aggressive position on mercury contrasts sharply with that of the
Food and Drug Administration (FDA), which has recently argued that the
benefits of eating mercury-tainted seafood may outweigh the risks.  FDA
should reverse course and not only maintain but elaborate on the
guidance it and EPA issued in 2004 <http://www.cfsan.fda.gov/~dms/admehg3.html>
 by adding more specific information about which low-mercury fish
people can eat in place of species like tuna and swordfish, that tend
to have elevated mercury levels.
 
Last December, EPA strongly criticized FDA efforts <http://www.ewg.org/node/27454>
 that aimed to revisit and water down a 2004 joint EPA/FDA warning
against consumption of tuna and other mercury-tainted seafood. <http://www.epa.gov/hg/advisories.htm>
 
The USGS study <http://www.doi.gov/news/09_News_Releases/050109.html>
shows how mercury pollution from Asia can be expected to build up
rapidly in the Pacific Ocean over the next few decades, in which case
mercury contamination in the seafood consumed by millions of people
would worsen dramatically.
 
EWG calls mercury in fish “clear and present danger”

“The prospect of ever-increasing levels of mercury in the Pacific Ocean
and in tuna makes it even more urgent that FDA give the public more
specific advice on fish that are safe to eat,” said Jane Houlihan,
Environmental Working Group (EWG) Vice President for Research.
 
 “FDA should develop a list of low-mercury fish that women and other
high-risk groups can eat without fear of ingesting significant amounts
of mercury,” Houlihan said. “FDA’s new leadership should take immediate
steps to protect the public health from the clear and present danger of
mercury.”