Dear Friends/Co-sailors,
For today's pick of my blog, I am sharing a news report by Darryl Fears published in 'washingtonpost'. The report brings to us information on a first of its kind study that shows how warmer water temperatures will increase levels of mercury in fish. Most of this mercury comes into our water from coal-fired power plants, mining and other such forms of industrial activities. We cannot dissolve mercury from our food and the fact that the globe is warming is going to take us to a future laden with irrecoverable health risks.
Our rush for coal is not only heating the local water and adding up to the global climate change, but also adding up to the mercury content in our life. And this is just going to increase. Consider a latest report by ADB that points out "Demand for coal in Asia and the Pacific will increase by 52.8% from 2010 to 2035, reaching 3,516.3 million tons of oil equivalent (Mtoe) by 2035". This means a huge increase in Carbon dioxite (CO2) emissions in these regions. The same report says 'Carbon dioxide (CO2 ) emissions in Asia and the Pacific as a whole will increase from 13,404.0 million tons of CO2 (Mt CO2 ) in 2010 to 22,112.6 Mt CO2 in 2035 at a growth rate of 2.0% per year'. But remember, we are targetting at a two digit growth rate!
It is high time we shun coal, replan our energy demand and generation situations and strategize for green sources of energy.
Hope you will find this relevant and send in your feedback/suggestions.
Thanks and regads,
Ranjan
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Study links warmer water temperatures to greater levels of
mercury in fish
By Darryl Fears, Monday, October 14
Under the watchful eyes of scientists, a little forage fish
that lives off the southern coast of Maine developed a strangely large
appetite.
Killifish are not usually big eaters. But in warmer waters,
at temperatures projected for the future by climate scientists, their
metabolism — and their appetites — go up, which is not a good thing if there
are toxins in their food.
In a lab experiment, researchers adjusted temperatures in
tanks, tainted the killifish’s food with traces of methylmercury and watched as
the fish stored high concentrations of the metal in their tissue.
In a field experiment in nearby salt pools, they observed as
killifish in warmer pools ate their natural food and stored metal in even
higher concentrations, like some toxic condiment for larger fish that would
later prey on them.
The observation was part of a study showing how killifish at
the bottom of the food chain will probably absorb higher levels of
methylmercury in an era of global warming and pass it on to larger predator
fish, such as the tuna stacked in shiny little cans in the cupboards of
Americans and other people the world over.
“The implication is this could play out in larger fish . . .
because their metabolic rate is also increasing,” said Celia Chen, a professor
at Dartmouth College in New Hampshire and one of six authors of the study.
“Methylmercury isn’t easily excreted, so it stays. It suggests that there will
be higher methylmercury concentrations in the fish humans eat as well.”
Methylmercury is linked to high blood pressure, kidney
disease and heart attacks in adults and slow neuro-behavioral development in
children. A thousand tons of the contaminant drops onto oceans every year from
power plant emissions, and more than 250 tons pour from the land into various
waters as a result of deforestation.
Top predators on land and sea have higher levels of mercury
because of their prey. It is hard for any organism to release the metal,
causing it to accumulate, or biomagnify, as scientists say.
The study, “Experimental and Natural Warming Elevates
Mercury Concentrations in Estuarine Fish,” was published in the journal PLOS
One in April, and officials at Dartmouth called attention to it ahead of last
week’s Minamata Convention on Mercury in Japan.
Delegates from 130 nations at the three-day convention that
ended Friday met to sign a treaty that seeks to greatly limit emissions from
coal-fired power plants from industrial nations, mining operations in Africa
and other sources that pollute oceans.
Every U.S. state has issued fish consumption advisories for
mercury, and there is a particular concern among states bordering the Gulf of
Mexico over health risks related to eating seafood containing mercury.
In spite of these concerns, there was no U.S. delegation in
Japan. A small U.S. contingent rushed there before the convention but was
recalled to the United States when the federal government shut down, according
to a report by Scientific American.
“No one from the U.S. is here and no one from the U.S.
government will walk to the front of the room and sign the treaty in front of
the global community,” Joseph DiGangi, an adviser at the International POPs
Elimination Network, a group devoted to reducing toxic chemicals, or
“persistent organic pollutants,” was quoted as saying.
A 2007 World Health Organization report warned that “eating
contaminated fish and shellfish is the main source of methylmercury exposure”
and that the metal cannot be cooked out. The WHO recommended that mercury
should be “eliminated wherever possible” and that exposure should be reduced.
But the killifish study suggested a future of fish with
higher levels of mercury in a warming world, not less.The list of sources that place mercury in the air and water
is long. In addition to power plants and deforestation, there are industrial
boilers, tooth fillings, car batteries, cosmetics, medical tools, vaccines and
even some soaps.
“The study is the first of its kind to demonstrate, in both
field and laboratory conditions, that methylmercury concentrations in killifish
increase with temperature,” said the study’s lead author, Jennifer A. Dijkstra,
a University of New Hampshire professor who was a researcher for the Wells
National Estuarine Research Reserve in Maine when the killifish were observed
between July 2009 and September 2010.
“This increase can be propagated up through the food web to
fish that are consumed by humans, resulting in greater human exposure to
methylmercury,” she said.
The other authors of the study were Kate L. Buckman of
Dartmouth; Michele Dionne of the Wells research reserve; David W. Evans, a
researcher for the National Oceanic and Atmospheric Administration’s Center for
Coastal Fisheries and Habitat Research in Beaufort, N.C.; and Darren Ward, a
researcher for the Department of Fisheries Biology at Humboldt State University
in Arcata, Calif.
The scientists decided to measure outdoor temperatures in
the pristine salt pools where killifish dwell in Maine and set temperatures in
lab tanks at the research reserve that matched air and marine warming
projections by the world’s top climate scientists.
They found six salt pools of about the same size in wetlands
of the Little River estuary along the Gulf of Maine that had higher
temperatures at different elevations.
Killifish in the field ate what they normally eat. In the
lab they ate feed tainted with methylmercury. In both cases, they fed greedily
in warmer water. Because of their higher metabolism, killifish did not gain
weight, but they gained more metal than usual.
To determine that, the scientists collected the fish from
the wild and labs using nets, then severed their little spines to euthanize
them for tests.
Methylmercury accumulation in killifish in a salt pool where
the water temperature reached 71 degrees was 400 percent higher than killifish
in a pool with cooler water, 64 degrees, over four months of study ending in
October 2010.
In the lab, methylmercury accumulation in killifish in tanks
with the water temperature set at 80 degrees was 30 percent higher than those
in water set at 59 degrees. But that study was shorter, 30 days each in March
and May 2011.
“What it suggests is with increased temperature the uptake
of methylmercury is going to be higher. . . . You can have higher contamination
of fish tissue,” Chen said. “One of the most important effects will be the
temperature effect.”
http://www.washingtonpost.com/national/health-science/study-links-warmer-water-temperatures-to-greater-levels-of-mercury-in-fish/2013/10/13/c86d43c6-3113-11e3-9c68-1cf643210300_story_1.html