Posted on 08/10/2005 5:26:23 AM PDT by dennisw
Let’s start with a straightforward fact:
Mercury is unimaginably toxic and dangerous.
A single drop on a human hand can be irreversibly fatal.
A single drop in a large lake can make all
the fish in it unsafe to eat.
Often referred to as quicksilver, mercury is the only common metal that is liquid at room temperature. Alchemists, including the young Sir Isaac Newton, believed it was the source of gold. In the modern era, it became a common ingredient of paints, diuretics, pesticides, batteries, fluorescent lightbulbs, skin creams, antifungal agents, vaccines for children, and of course, thermometers. There is probably some in your mouth right now: So-called silver dental fillings are half mercury.
Mercury is also a by-product of many industrial processes. In the United States coal-fired power plants alone pump about 50 tons of it into the air each year. That mercury rains out of the sky into oceans, lakes, rivers, and streams, where it becomes concentrated in the flesh of fish, shellfish, seals, and whales. Last year the Food and Drug Administration determined there is so much mercury in the sea that women of childbearing age should severely limit their consumption of larger ocean fish. The warning comes too late for many mothers. A nationwide survey by the Centers for Disease Control shows that one in 12 women of childbearing age already have unsafe blood levels of mercury and that as many as 600,000 babies in the United States could be at risk. But that begs a critical question: At risk for what?
_________________________________________
TUNA TYPES
One particularly common source of low-level mercury exposure is tuna. Because they are large, long-lived predators, tuna accumulate more mercury in their tissue than smaller, short-lived fish. When tested for mercury in parts per million, flesh from albacore tuna, which take five years to mature, was shown to contain about four times as much mercury as chunk light tuna, which is harvested from younger fish. ______________________________________________
Infants born to mothers contaminated by mercury in Japan’s Minamata Bay in 1956 had profound neurological disabilities including deafness, blindness, mental retardation, and cerebral palsy. In adults, mercury poisoning can cause numbness, stumbling, dementia, and death. “It’s no secret that mercury exposure is highly toxic,” says toxicologist Alan Stern, a contributor to a 2000 National Research Council report on mercury toxicity. But high-level exposures like those at Minamata cannot help scientists determine whether six silver fillings and a weekly tuna-salad sandwich will poison you or an unborn child. “The question is, what are the effects at low levels of exposure?” he says.
Data now suggest effects might occur at levels lower than anyone suspected. Some studies show that children who were exposed to tiny amounts of mercury in utero have slower reflexes, language deficits, and shortened attention spans. In adults, recent studies show a possible link between heart disease and mercury ingested from eating fish. Other groups claim mercury exposure is responsible for Parkinson’s disease, multiple sclerosis, Alzheimer’s, and the escalating rate of autism.
How—and in what form—mercury inflicts damage is still unclear. Yet scientists and policymakers agree that more regulation is imperative. The Environmental Protection Agency plans to finalize its controversial first rule on reducing mercury emissions from power plants this month, and delegates from the United Nations Environment Programme met in late February to discuss an international convention limiting mercury use and emissions.
A decade ago researchers and lawmakers agreed that lead, another heavy metal, was harmful to children at levels one-sixth as high as previously recognized. But it took scientists decades to establish the scope and subtlety of lead poisoning. Mercury is now a ubiquitous contaminant. The average American may have several micrograms of it in each liter of blood, and the atmospheric burden of mercury has perhaps tripled since the industrial age. Whatever needs to be done to protect humanity from its love affair with quicksilver, it had better happen soon.
In August 1996 Karen Wetterhahn, a chemistry professor at Dartmouth College in Hanover, New Hampshire, spilled a few drops of a laboratory compound called dimethyl mercury onto one of her hands. She was wearing latex lab gloves, so she didn’t think much of it. A colleague saw her at a conference the following November. “She said she thought she was coming down with the flu,” says toxicologist Vas Aposhian of the University of Arizona. By the time Wetterhahn was diagnosed with mercury poisoning, in January, it was too late. Despite subsequent treatment that helped clear the metal from her body, she lapsed into a vegetative state in February and died the following June.
Scientists are at a loss to explain why mercury often takes months to exert its effects. “If we knew that, we’d know a lot more about how mercury poisons the brain,” says Tom Clarkson, a toxicologist at the University of Rochester Medical Center.
The degree of mercury’s toxicity depends on the form and route of exposure. You can swallow the liquid form of elemental mercury without much fear because it doesn’t easily penetrate the lining of the stomach and intestines. On the other hand, liquid mercury vaporizes at room temperature, and when you inhale the vapor it moves right from the lungs to the bloodstream to the brain. A broken thermometer can release enough mercury vapor to poison the air in a room—one reason why some cities and several states discourage the sale of mercury fever thermometers.
Mercury also binds with other elements in salts and organic compounds of varying toxicity. Dimethyl mercury, the substance that poisoned the Dartmouth chemist, is a synthetic form of organic mercury rarely found outside a lab. A simpler organic compound called methylmercury is of greater concern because methyl- mercury is the form found in the flesh of fish.
Seafood is one of the two most common sources of mercury exposure in adults. Although concentrations of mercury in air and water are increasing, they are still too small for alarm. But bacteria process the mercury in lakes and oceans into a form that accumulates in living tissue. Plankton take in the bacteria and are in turn eaten by small fish. With each meal, the mercury concentration rises. Then larger fish eat the small fish, increasing tissue concentrations still more. Fish at the top of the food chain accumulate the most mercury. The species singled out by the recent FDA advisory—big predators such as albacore tuna, shark, and swordfish—can have 100 times more mercury in their tissues than smaller fish do.
The methylmercury in fish passes readily from the human gut to the bloodstream and on into all organs and tissues. It seems to act most powerfully on the brain because the compound is strongly attracted to fatty molecules called lipids, and the brain has the highest lipid content of any organ. Methylmercury crosses the protective blood-brain barrier by binding with an essential amino acid that has dedicated carrier proteins for shunting it into brain cells. Once inside brain cells, some of it gets converted to an inorganic form that sticks to and disables many structural proteins and enzymes essential to cell function. “It can destroy the biological function of any protein it binds to,” says Boyd Haley, a biochemist at the University of Kentucky.
Researchers learned how much mercury the body can tolerate from studies of victims of catastrophic poisoning, such as the Japanese sickened by eating fish from Minamata Bay and the Iraqis who ate grain treated with a methylmercury-based preservative in the early 1970s. But those studies do not reveal how little mercury it takes to cause harm. At the time of her diagnosis, the Dartmouth chemist had 4,000 micrograms of mercury per liter in her blood. A diet consistently high in fish can create a blood-mercury level of about 25 micrograms per liter. That’s far below a lethal dose, but it still may not be safe.
What did you replace them with? Some super holistic dentists try to vacuum up that vapor and put you on supplements to purge the mercury from your bloodstream that inevitability enters from the removal of amalgams
That has been established already. To say that a single drop of MERCURY on the hand can be fatal is wrong. She didn't say a single drop of DIMETHYL MERCURY in the opening paragraphs. They certainly are not the same. Not many of us played with dimethyl mercury as kids. If we had, we wouldn't be here.
The author simply declined to mention the FORM of mercury. Yes, anyone can handle little balls of metallic mercury without harm (at least in the short term -- too many of them in a room will present a volatilization hazard, especially if they are small and thus have a high surface area-to-volume ratio). But I think what the author was referring to was dimethyl mecury which was spilled on a professor's laboratory gloves, as was reported in a news release (below) from the late 1990's. It took 10 months to kill the victim,
A news release that was circulated:
Exposure to Mercury Kills Dartmouth Professor
ANOVER, N.H. -- A Dartmouth College chemistry professor has died from exposure to a rare form of mercury, first synthesized more than 130 years ago.
Karen E. Wetterhahn, 48, who also had served as an associate dean and a dean at the college, died on Sunday, about 10 months after accidentally spilling a few drops of dimethylmercury on her disposable latex gloves while
performing a laboratory experiment. The substance, which has no practical application, is used in research on heavy metals.
Professor John S. Winn, chairman of the college's chemistry department, said Professor Wetterhahn was an internationally recognized leader in the study of how heavy metals can initiate cancer at the molecular level.
Dimethylmercury is so rare that it is only in use in perhaps 100 laboratories worldwide at any given time, he said.
Through a search of medical literature, the college determined that exposure to the substance killed two laboratory assistants in 1865, shortly after it was first synthesized, and a 28-year-old chemist in 1971.
"Karen Wetterhahn's death is a tragedy for her family and for the Dartmouth community-- the students, colleagues and friends who have come to love her generosity of spirit, to rely on her talents and to respect her ground-breaking work, "said Dartmouth's president, James O. Freedman.
After years of studying chromium metal toxicity, Professor Wetterhahn had turned to the study of mercury in a sabbatical at Harvard University in September 1995, Winn said.
In the experiment at Dartmouth last August, she had used dimethylmercury to set up a standard against which to measure other mercury involved in her research.
The drops apparently spilled onto her gloves, passed quickly through the latex and were absorbed through her skin. After her illness was diagnosed in late January, the college had the latex gloves independently tested, and
it was determined that the mercury could pass through in 15 seconds or much less.
Although she washed her hands after the accident, Professor Winn said, "I just don't think she had any idea of the peril she was in when the spill occurred."
Other types of gloves offer more protection, but she probably used latex to increase dexterity during the delicate procedure, he said.
In a letter to Chemical and Engineering News about the accident, Winn and two other college officials recommended that heavier gloves be used during such experiments, and that "medical surveillance measuring mercury
concentrations in whole blood or urine" should be considered during extended use of these compounds.
Wetterhahn's symptoms, which initially included difficulty with balance, speech, vision and hearing, progressed rapidly and she was in a coma from late February until her death. Although treatments were administered to
eliminate the mercury in her system, they began too late to prevent irreversible damage to the nervous system, Winn said.
Well, if fillings are fatal I'm doomed. My mouth is silver from the fangs back. I have Irish teeth.
["A single drop on a human hand can be irreversibly fatal."
Bull... I use to play with it all the time when I was a kid, never even got sick let alone died...obviously...]
I plaide wit it to as a kid, an it dint effect me one bit.
I could not find a doctor in my insurance network who knew how to treat this but was fortunate enough to find an M.D. with additional certification in alternative medicine who was able to treat me, albeit at my expense
Seriously, I have an old Honeywell Pentax Spotmatic camera (35m) which still works like a charm BUT can only use a Mercury Battery (for the light meter). I have 'heck' of a time find them. Fortunately, I found one little mom and pop camera shop that has them - and they're 'hidden' under the counter.
Buying Heroin or an UZI is easier than finding a Mercury camera battery.
When I was a kid, several times I put mercury in a pan on the stove and heated it until it boiled away. I probably absorbed a good amount of vapor.
I am pushing 60 and have no unusual health issues.
It is not the vapor alone that is deadly, again, it is the amount.
This proves beyond the shadow of a doubt, that ignorance truly is bliss.
As a child, my class mates and I often held palms full of mercury and played with it for days, coating coins and making them appear mint contition and just rolling the shiny little droplets around in our hands.
We all owe our lives to being blissfully ignorant.
Or just another "publish or perish" piece of work……or someone looking for 'grant money'.
Also remember the Mad Hatter in Alice in Wonderland? Mercury was once used to treat felt. Hatters (hat makers) would chew the felt to help reshape it, thus exposing themselves to the mercury...
usually plastic
Would you explain the difference for us and tell us how to avoid contact with the lethal Mercury?
So the cat is right! She won't eat the albacore, only chunk light tuna....if it's packed in water with salt.
Metallic mercury is the silver liquid found in older thermometers.
Here's info on methyl mercury:
http://en.wikipedia.org/wiki/Dimethylmercury
You would have a hard time getting exposed to a fatal amount of it unless you worked in a lab that used it. Don't worry about it.
Not any more. But they used to.
The kind of mercury that can kill with a single drop of exposure is dimethylmercury...it is a man made mercury used in labs, not the kind used in thermometers.
Here's a link to a story about a scientist who died after exposure to dimethylmercury...she was exposed even though she had on latex gloves, and she died some time later from the exposure.
http://www.mercuryexposure.org/index.php?article_id=17
Po' folks screwed agin I reckon, they jus' can't afford that chunk lite tuna.
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