The bad news is that this increase is only the beginning--the curve is headed for the ceiling. I find it remarkable that my current Harvard-educated nutrition teacher talks about the health value of eating fish without expressing concern about mercury content. The research hasn't penetrated his consciousness yet. But it will.

I've stopped eating sushi since I tested with high mercury, arsenic, and very high lead levels, about a year ago. I have no idea where all my heavy metals came from, but I did eat a lot of sushi for a while there. I did a round of oral DMSA chelation. I'm going to retest soon to see if how much that treatment decreased my body load.


USGS STUDY SHOWS BIG INCREASES IN MERCURY CONTAMINATION OF FISH
--data comes from new study by U.S. Geologic Survey
--http://toxics.usgs.gov/investigations/mercury.html
--mercury contamination in tuna and other Pacific fish has increased 30% since 1990
--increase dt China's rapid industrialization
--mercury content is expected to increase another 50% by 2050 if China keeps building coal-fired power plants
--US contributes 40 tons of mercury/year (mostly coal burning) so we're in a glass house here
--coal burning, waste incineration, cement kilns, some mining-->release elemental Hg into environment
--since industrial revolution humans have increased atmospheric mercury levels x3-->ecosystems loaded
--approx 40% of all U.S. exposure to mercury comes from eating contaminated Pacific tuna
--approx 75% of all human exposure comes from eating fish
--bacteria eating algae convert it to methylmercury in the mid-depth waters of the ocean

IF YOU'RE PREGNANT OR PLANNING TO BE
--the EPA's 2004 advice to pregnant mothers is bunk IMHO
--they tell you it's OK to eat light canned tuna but it is not
--http://www.epa.gov/waterscience/fish/advice/
--if you're going to eat fish, go for small (anchovies, sardines), noncarnivorous, wild (Alaskan salmon), Atlantic or northern species
--most contaminated: tuna, sea bass, marlin, and halibut
--avoid for sure per Mercola: tuna, sea bass, oysters (Gulf of Mexico), marlin, halibut, pike, walleye, white croaker, largemouth bass, shark, swordfish
--small amounts of mercury really bad for fetus: don't eat fish
--take a fish or krill oil supplement instead, really do take it, it's important for brain development
--in fetuses and infants: damage to attention span, language, visual-spatial skills, memory, coordination
--estimate: nearly 60,000 children each year at risk for neuro probs dt MeHg exposure in utero
--2005 CDC report found that one in 17 women of childbearing age have mercury levels that could harm a fetus
--dangerous level: above 5.8 micrograms per liter
--just one serving of very contaminated fish could harm your fetus

DIURNAL VARIATIONS IN STREAM METAL CONCENTRATIONS
--in Montana streams concentrations are highest in the afternoon, daily cycles
--http://toxics.usgs.gov/highlights/mercury_streams.html
--this confirms earlier research showing diurnal variations in streams metal levels
--http://toxics.usgs.gov/highlights/diel_metal.html

SIGNS OF METHYLMERCURY TOXICITY
--paraesthesias
--depression
--blurred vision
--arrhythmias and cardiomyopathies
--tremors
--insomnia
--personality changes and irritability
--headaches
--weakness
--slowed mental response
--unsteady gait

MERCURY NOT EASY TO REMOVE
--binds to CNS with half life of 15-30 years

ON TUNA
--in 2007, canned tuna was the second most eaten seafood, with the average American eating nearly 3lbs
--tuna like bluefin can grow to 550 pounds and concentrate the mercury from all the small fish they eat
--lab tests in New York, 2007 found tuna sushi levels dangerously high
--10% of tuna samples were unsafe: mercury levels above 1.0 ppm (legal limit in US)
--6% of light tuna cans tested contained more than 0.35 ppm, and as much as 0.85 ppm in 2007
--white or albacore canned tuna averaged 0.35 ppm

SOURCES

Mercola
http://articles.mercola.com/sites/articles/archive/2009/05/21/Your-Tuna-is-Getting-More-Toxic.aspx

USGS
http://toxics.usgs.gov/investigations/mercury.html

The Daily Green May 6, 2009
http://www.thedailygreen.com/environmental-news/latest/tuna-mercury-47050102

Global Biogeochemical Cycles May 1, 2009
http://www.agu.org/pubs/crossref/2009/2008GB003425.shtml

USGS on cycling in streams
http://toxics.usgs.gov/highlights/mercury_streams.html
http://toxics.usgs.gov/highlights/diel_metal.html

EPA advice
http://www.epa.gov/waterscience/fish/advice/