Mercury in Fish
In America one-in-six children born every year have been
exposed to mercury levels so high that they are potentially at risk
for learning disabilities and motor skill impairment and
short-term memory loss. That type of mercury exposure is
caused by eating certain kinds of fish, which contain high levels
of the toxin from both natural and man-made sources such as
emissions from coal-fired power plants. One government
analysis shows that 630,000 children each year are exposed to
potentially unsafe mercury levels in the womb. If the government
and its scientists know about the mercury problem, why do so
many people continue to be poisoned?
Over recent years NOW has examined how the influence of the
tuna industry on the FDA may be putting Americans and their
children at risk for mercury poisoning. Tuna, widely known for its
health benefits, is one of the most popular foods on grocery
store shelves. And, in 2000, FDA draft advisories presented to
focus groups warned women not to eat a lot of canned tuna
during pregnancy because it contains levels of mercury that can
harm developing fetuses and nursing babies. In March 2004, the
FDA and the EPA issued the first ever joint advisory on this topic,
What You Need to Know About Mercury in Fish and Shellfish.
The State of California has gone a step further. In 2003 the
California Attorney General's office filed suit to force
supermarkets, restaurants and tuna companies to warn
customers that tuna (fresh, frozen and canned), swordfish and
shark sold in their markets contain mercury. The suit was based
on the state's Proposition 65 which requires consumer warnings
for substances on a toxics list. The state also provided special
warnings advising women and children to "Limit their
consumption of other fish, including tuna." And they further
advised that "tuna steaks and canned albacore have higher
levels of mercury than canned light."
In January 2005, 16 major restaurant chains sued by the state
agreed to settle and put up warnings. And a few supermarkets
have voluntarily posted them at fresh fish counters and in the
frozen food section. The US Tuna Foundation is challenging the
lawsuit saying "canned tuna products are safe
." Citing the
above-mentioned mercury advisory by the Food And Drug
Administration and the Environmental Protection Agency that
states "fish and shellfish are an important part of a healthy diet."
Find about more about mercury in fish below.
Nearly all fish contain trace amounts of methylmercury. How
does this element get into our fish supply? Mercury occurs both
naturally and from man-made sources. Some of it can be traced
to coal-burning power plants. Smokestacks release toxic
mercury emissions which rain down into rivers, lakes, and
oceans. Bacteria convert the mercury to a form that's easily
absorbed by insects and other small organisms. Mercury moves
up the food chain as small fish eat the small organisms and big
fish eat the smaller fish. The highest concentrations accumulate
in large predators such as shark, swordfish and tuna...some of
America's favorite fish.
Pregnant women, nursing mothers, and very young children are
cautioned against excessive consumption of these fish. Read
the FDA consumer advisory for pregnant women about the risks
of mercury in fish. The FDA also offers a chart on mercury levels
in seafood species.
Until the 1950's, the problems that can occur with excessive
mercury intake were not well-known. However, at that time, an
epidemic hit fishermen and their families in villages on Japan's
Minamata Bay. People whose diet was primarily seafood
showed signs of brain damage; some were even fatally stricken
with disease and seizures. The investigation linked the health
problems to methylmercury poisoning from a local chemical
plant that was discharging organic mercury into the bay. The
villagers were getting sick from eating the fish that had absorbed
the mercury. (Learn more about The Poisoning of Minamata.)
In 1969, the FDA first set an action level for total mercury in fish;
0.5ppm (part-per-million) was considered the maximum safe
limit. (Action levels represent the limit at or above which FDA will
take legal action to remove a product from the market.) In 1979,
the action level was raised to 1ppm. In 1984, there was another
major change. The FDA stopped measuring on a basis of total
mercury and instead started checking levels in terms of
methylmercury only. In 1998, the FDA stopped widely testing for
mercury in fish.
Around the world, there is concern about mercury contamination
through fish, but specific recommendations vary. For example,
Health Canada advises consumers to limit their consumption of
swordfish, shark or fresh and frozen tuna to one meal per week;
for young children and women of child-bearing age, the
recommended limit is one meal per month. Health Canada's
guideline is 0.5ppm total mercury content more stringent than
in the U.S. Britain's Food Standards Agency is advising pregnant
and breastfeeding women and women who intend to become
pregnant to limit their consumption of tuna to no more than two
medium-size cans or one fresh tuna steak per week.
Even within the United States, women are hearing different
advice from different sources, especially where tuna is
concerned. The EPA's methylmercury guideline is a
recommended limit on mercury consumption based on
bodyweight, also known as a "reference dose." EPA's
methylmercury reference dose is .1 micrograms/kg body weight
per day. In July 2000, the National Academy of Sciences found
the EPA's reference dose as "scientifically justifiable" for
protecting most Americans.
So exactly how much mercury a 45 lb. child would ingest by
eating one 6 ounce can of tuna per week, and how does that
compare to the EPA's reference dose? Take a look at the
Step 1 - DETERMINE EPA's RECOMMENDED LEVEL FOR A 45
* Multiply child's body weight by EPA's reference dose.
* Convert 45 pounds to kilograms = 20.45 kilograms
* 20.45 kilograms x .1 micrograms per kilogram per day
EPA RECOMMENDED LEVEL = 2.05 micrograms per day =
14.35 micrograms per week.
Step 2 - HOW MUCH MERCURY IS IN 6 OUNCES OF CHUNK
* Multiply amount of fish by average mercury level for chunk white
* Convert 6 ounces to grams = 170 grams 170 grams X .31 ppm
(or micrograms per gram)**
MERCURY INGESTED = 52.7 micrograms per gram
Step 3 COMPARE MERCURY INGESTED WITH EPA'S
* Divide 52.7 micrograms by 14.35 micrograms = 3.7
BY EATING 6 OUNCES OF CHUNK WHITE TUNA A WEEK, THE
CHILD IS INGESTING ALMOST FOUR TIMES EPA'S
In December 2003, the FDA began circulating a draft advisory
warning women who are pregnant, nursing, or who might
become pregnant about the dangers of mercury in seafood.
Critics like the Environmental Working Group objected to the
advisory's vague guidance on tuna, and subsequently filed a
legal challenge, charging that the advisory did not meet
standards for accurate government science established by the
Data Quality Act.
In February 2004, a new analysis by the Environmental
Protection Agency revealed that "about 630,000 children are born
each year at risk for lowered intelligence and learning problems
caused by exposure to high levels of mercury in the womb,"
nearly double the previous EPA estimate.
Read more about mercury and tuna from the Mercury Policy
Project and from the U.S. Tuna Foundation.
Also, the Sea Turtle Restoration Project Mercury Calculator
allows users to gauge mercury exposure from seafood by
entering a log of how much fish they consume.
**Average for Chunk White Canned Tuna. Yess, Norma J. "US
Food and Drug Administration Survey of Methyl Mercury in
Canned Tuna," Journal of AOAC International, Vol. 76, No. 1,
1993, pp. 36-38.
I studied with Hanna Kroger for many years. Hanna owned the
first health food store in Boulder where Mo Segel sold herbs that
he had collected for tea. And this was the humble beginning of
the Celestial Seasonings Tea Company. I always felt Hanna
was a kindred spirit but when I opened one of her little books
today, this one entitled, "God Helps Those who Help
Themselves," I read the dedication from 1984:
"I dedicate this book to the protector of America, St. Michael, and
to his Army of Torchbearers."
I wonder how many more such dedicated individuals might be
Hanna was a prolific author and wrote on Lead as a factor in the
downfall of Rome and the Sim40 polio vaccination as being a
major detriment to (the death of) the "sixties generation" and
countless more topics. Here is a little on what she has to say
Ethyl and methyl compounds of mercury are used for fungal
diseases of cereals and grain. These compounds have an
affinity for the central nervous system and produce:
Loss of hearing, deafness
Progressive visual deterioration
Loss of coordination
Anxiety, mental depression
Loss of memory
Coma and death
Symptoms of chronic mercury poisoning include:
Excessive salivation and metallic taste.
A blue line develops above the gingival margin.
Gums become hypertrophied, bl;eed easily, and are sore.
Teeth become loose.
Tremors of eyelids, lips, tongue, fingers and extremities.
Course, jerky movements and gross incoordination interfere with
fine movements such as writing and eating.
Atrophy of the cerebellar cortex and, to a lessor extent, of the
cerebral cortex occurs.
Microscopic changes occur in the granular layer of the
cerebellum, ganglion cells and posterior columns.
Children exposed to toxic amounts of lead and other metal
pollutants are subject to severe behavioral disorders resulting
from damage to the central nervous system (Byers and Lord,
1943: Pfeiffer, 1977). It remaind to be determined if sub-toxic
metal levels are an etiologic agent in behavioral disorders,
Sub-toxic lead levels previously thought harmless are now being
associated with hyperactivity, impulsiveness, short attention
span and immaturity. Recent nurochemical studies of Dr.
Silbergeld and Houshka (1980) showed that lead and mercury
are potent neurotoxins. Their effects are demonstrated in the
neuronal system by using tests with acetylcholine,
catecholamines and GABA (gamma-aminobutyric acid) as