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Fish In Your Diet – Not Health Food Anymore: Mercury in Fish
If you eat a lot of fish, you may be risking your health.
We have all been told that eating fish is an important part of a balanced diet. It's full of vitamins and other nutrients, good for our hearts because the omega-3 fatty acids lower cholesterol and blood pressure, and fish is low in calories.
But new studies are raising concerns about the unsafe levels of mercury and other contaminants found in fish that are causing health problems.
Who is at risk?
The effects of mercury contamination are a cause of concern for us all.
Warnings have been issued for pregnant women and children. But, in a recent clinical study, high levels of toxic mercury, called methylmercury, were discovered in blood and hair samples taken from dozens of patients -- men, women and children. .
What are the symptoms of mercury poisoning?
BlueVoice recently spoke with San Francisco physician Jane Hightower, whose year long study was recently published in Environmental Health Perspectives, an online journal which is part of the National Institutes of Health. The study concluded that even low-level mercury poisoning has been found to cause memory loss, hair loss, fatigue, depression, difficulty concentrating, tremors and headaches. Because it is hard for the body to eliminate, it can build up and may affect the nervous system.
Dr. Hightower noted that it is not known how many people might be affected by methylmercury, and while she could not measure how much of their suffering was directly related to the over-consumption of fish, the symptoms stopped when fish was eliminated from their diet.
Limiting Intake of Tuna and other fish
Dr. Hightower stressed that while fish can be part of a healthy diet, people need to be aware which are the problem fish and which are the healthful fish low in mercury and other contaminants.
Mercury poisoning in fish is of particular concern because fish accumulate the methylmercury in their tissues. Mercury contamination is of the biggest concern in the larger, longer-living fish as it accumulates as it moves up the food chain. Fish such as tuna, swordfish, Chilean sea bass, Alaskan halibut, tilefish and King mackerel have been show to have extremely high levels of mercury. Wild caught salmon, sardines, cod, tilapia, sole, shrimp, and herring have lower levels of mercury.
"Tuna is the most consumed fish in the country," says Michael Bender of the Mercury Policy Project, an advocacy group. "A pregnant woman who eats over two cans of tuna per week, can go over safe levels of mercury
How does mercury contaminated fish get into our diets? Read on . .
Coal Burning Power Plants: Mercury Polluters
According to an Environhealthaction.org report posted by the Washington D.C. watchdog group, Physicians for Social Responsibility, "Power plants are the source of approximately one third of the nation's mercury pollution. Mercury released from power plants accumulates in the food chain and can be ingested as part of our diet. Individuals can also inhale mercury in the air, or be exposed to mercury in the water or soil.”
Other sources of mercury pollution are municipal waste combustors, medical waste incinerators and hazardous waste combustors. Even in areas where industrial pollution has been reduced, the problem persists because of atmospheric pollution drifting from other areas.
The 2003 EPA database shows that a staggering number of the United State’s waterbodies are under advisories.
The 2003 Environmental Protection Agency’s NLFWA database lists 3,089 advisories in 48 states, the District of Columbia and the U.S. territory of American Samoa. The number of waterbodies under advisory represents:
- 35% of the nation’s total lake acres (14,195,187), or approximately 101,818 lakes –(up from 8% in 1993)
- 24% of the nation’s total river miles), or approximately 846,310 river miles – up from 2% in 1993)
- 71% of the nation’s contiguous coastal waters including:
- 92% of the Atlantic Coast and
- 100% of the Gulf Coast.
- 100% of the Great Lakes and their connecting waters.
The 2003 National Listing of Fish Advisories database shows that the number of safe eating guidelines issued continues to rise rapidly, and that states, territories and tribes also continue to issue new fish advisories, with most new fishing advisories involving mercury.
In 2003 advisories have been issued for 40 different pollutants, most advisories involve 5 primary bioaccumulative contaminants, with mercury topping the list.
Mercury – 2,362 advisories (up 20% from 2002)
PCBs – 884 advisories (up 9% from 2002)
Chlordane – 89 advisories (down from 97 in 2002)
Dioxin – 90 advisories (up from74 in 2002)
DDT + metabolites – 52 (up from 48 in 2002
Mercury pollution is a global problem
A survey of Hong Kong high school students
Ten percent of students in Hong Kong were found to be consuming enough fish to exceed safety limits for mercury exposure. The World Health Organization recommends a 5-microgram limit, but when it was discovered that these students had an exposure of 6.41 micrograms per kilogram (2.2 pounds) of body weight a week, the Chinese government issued a warning about consumption of shark and other large fish.
Whale and dolphin meat consumed in Norway and Japan may contain some of the world's most dangerous toxins.