Dangers of Mercury and Its Effects

[Guest guest]

Good article on mercury with one glaring omission,...One of the

primary sources of mercury poisoning IS dental amalgams for teeth

fillings and the only mention of it here is to say that it is " safe "

which is pure bulls__t.

 

 

 

SSRI-Research@

Thu, 26 May 2005 02:14:10 -0000

[sSRI-Research] Dangers of Mercury and Its Effects

Mercury Contamination in Fish: A Guide to Staying Healthy and

Fighting Back

 

 

 

http://www.nrdc.org/health/effects/mercury/index.asp

 

Eating fish contaminated with mercury, a poison that interferes with

the brain and nervous system, can cause serious health problems,

especially for children and pregnant women.

 

Learn About Mercury and Its Effects

 

Mercury pollution can be a serious health threat, especially for

children and pregnant women.

 

Over the years, many companies have used mercury to manufacture a

range of products including thermometers and thermostats, automotive

light switches and " silver " dental fillings. Although the metallic

mercury in these products rarely poses a direct health hazard,

industrial mercury pollution becomes a serious threat when it is

released into the air by power plants, certain chemical manufacturers

and other industrial facilities, and then settles into oceans and

waterways, where it builds up in fish that we eat. Children and women

of childbearing age are most at risk.

 

Mercury in Fish

 

Once mercury enters a waterway, naturally occurring bacteria absorb

it and convert it to a form called methyl mercury. This transition is

particularly significant for humans, who absorb methyl mercury easily

and are especially vulnerable to its effects.

Mercury then works its way up the food chain as large fish consume

contaminated smaller fish. Instead of dissolving or breaking down,

mercury accumulates at ever-increasing levels. Predatory fish such as

large tuna, swordfish, shark and mackerel can have mercury

concentrations in their bodies that are 10,000 times higher than

those of their surrounding habitat.

 

Mercury and Human Health

 

Know Where It's Coming From

 

Each year power plants and chemical facilities create many tons of

mercury pollution, which makes its way into our homes and bodies in

fish.

Two of the biggest sources of mercury pollution are chlorine chemical

plants and coal-fired power plants. Chlorine plants, which use

massive quantities of mercury to extract chlorine from salt, " lose "

dozens of tons of mercury each year; power plants emit around 50 tons

of mercury pollution annually. Facilities that recycle auto scrap are

another big source of mercury pollution, pouring 10 to 12 tons of

mercury into the air every year. The most common way Americans are

exposed to mercury is through tuna fish.

 

Power Plants

 

Coal is naturally contaminated with mercury, and when it is burned to

generate electricity, mercury is released into the air through the

smokestacks. The bulk of this mercury pollution could be eliminated

with the installation of pollution-control devices. Similar devices

have proved very successful on municipal incinerators, which were

once a significant source of mercury pollution.

 

But in January 2004 the Bush administration proposed to weaken and

delay efforts to clean up mercury emissions from roughly 1,100 coal-

fired boilers at more than 460 electric power plants. Essentially,

the administration's plan treats mercury as if it were a run-of-the-

mill air pollutant instead of a hazardous air pollutant, allowing the

Environmental Protection Agency to avoid requiring power plants to

reduce emissions by the maximum amount technologically achievable.

 

Chemical Manufacturing

 

Big mercury polluters also include older mercury chlorine plants,

also called chlor-alkali plants, which use mercury to convert salt to

chlorine gas and caustic soda (better known as lye), which is used in

soaps and detergents. More modern chlor-alkali plants use a cleaner,

mercury-free technology. Only nine U.S. chlor-alkali plants continue

to use mercury. At any given time each of these plants has an average

of 200 tons of mercury on site, and collectively the plants use

dozens of tons of mercury annually to replenish the amount lost in

the manufacturing process. They cannot account for where the " lost "

mercury goes. Nor can the Environmental Protection Agency, but the

agency has failed to set restrictions on these emissions.

 

Automobile Scrap

 

Mercury pollution also occurs when mercury-based light switches from

automobiles are scrapped and melted down for recycling. As the

switches melt, the mercury they contain vaporizes into the air.

 

Following considerable public pressure, auto manufacturers stopped

using mercury in January 2003. But as long as older cars are

incinerated, mercury pollution will continue to escape into the air.

To prevent this, mercury-based car switches should be removed at the

scrap yard, before cars are shredded and sent to steel mills for

recycling. Removing the switches would take less than a minute per

car, on average -- a cost that should be borne by the companies that

installed them in the first place, not by the scrap industry. Some

states have passed or are moving toward legislation or regulations

requiring the removal of mercury switches from automobile scrap. But

the EPA has yet to introduce standards that will curb switch-related

mercury pollution nationwide. More information on mercury in

automobiles is available on the Clean Car Campaign's website.

 

Mercury in the Food We Eat

 

The most common source of mercury exposure for Americans is tuna

fish. Tuna does not contain the highest concentration of mercury of

any fish, but since Americans eat much more tuna than they do other

mercury-laden fish, such as swordfish or shark, it poses a greater

health threat. (For more, see our guides to mercury levels in fish

and to eating tuna safely.)

 

Subsistence and sports fishermen who eat their catch can be at a

particularly high risk of mercury poisoning if they fish regularly in

contaminated waters. Across the United States, mercury pollution is

known to have contaminated 12 million acres of lakes, estuaries, and

wetlands (30 percent of the total), and 473,000 miles of streams,

rivers, and coasts. And many waterways have not even been tested. In

2003, 44 states issued fish consumption advisories, warning citizens

to limit how often they eat certain types of fish caught in the

state's waters because they are contaminated with mercury.

 

Time On Our Side

 

While mercury is a so-called persistent pollutant, meaning that it

doesn't break down as some other pollutants do, its dangers lessen

considerably over time, because it eventually settles into the beds

of rivers, lakes and oceans and is covered over by successive layers

of sediment. At some point, fish stop consuming the mercury so

eventually it ceases to be a hazard to humans.

 

We can begin safeguarding our health now by stopping mercury

pollution at its sources.

 

Humans risk ingesting dangerous levels of mercury when they eat

contaminated fish. Since the poison is odorless, invisible and

accumulates in the meat of the fish, it is not easy to detect and

can't be avoided by trimming off the skin or other parts.

 

Once in the human body, mercury acts as a neurotoxin, interfering

with the brain and nervous system.

 

Exposure to mercury can be particularly hazardous for pregnant women

and small children. During the first several years of life, a child's

brain is still developing and rapidly absorbing nutrients. Prenatal

and infant mercury exposure can cause mental retardation, cerebral

palsy, deafness and blindness. Even in low doses, mercury may affect

a child's development, delaying walking and talking, shortening

attention span and causing learning disabilities.

 

In adults, mercury poisoning can adversely affect fertility and blood

pressure regulation and can cause memory loss, tremors, vision loss

and numbness of the fingers and toes. A growing body of evidence

suggests that exposure to mercury may also lead to heart disease.

 

Mercury and a High-Fish Diet

 

A January 2003 report from the federal Centers for Disease Control

and Prevention concluded that one in six women of childbearing age

have mercury in their blood above the level that would pose a risk to

a developing fetus.

 

Dr. Jane Hightower, a doctor of internal medicine at the California

Pacific Medical Center in San Francisco also linked fish consumption

to elevated mercury levels when she tested her own patients. Her 2003

study found that 89 percent of the participating patients -- chosen

because of their fish-heavy diets -- had elevated mercury levels.

Many had levels as much as four times that which the Environmental

Protection Agency considers safe.

 

The good news is that Dr. Hightower and other health professionals

conclude that high mercury levels are reversible: cutting consumption

of mercury-contaminated fish causes blood mercury to drop, though it

can take six months or more.

 

Toxic Chemicals & Health: Health Threats & Effects: In Brief: Guides

 

Protect Yourself and Your Family

 

With smart food choices you can lower your mercury level in about six

months; it will take longer to get it out of the fish -- so let's

start now.

Mercury poisoning is a serious problem, but the solutions are fairly

simple: in the short term, watch your consumption of high-mercury

fish; in the longer term, help force power companies and other giant

mercury polluters to switch to pollution-cutting technologies.

 

The recommendations in this section about eating fish are largely

designed for the people most at risk from mercury poisoning: children

and women of childbearing age. Other adults may not need to restrict

their diets as much, but can use these guidelines to make informed

choices.

 

Avoid Contaminated Fish

 

Children under six, as well as women who are pregnant or planning to

become pregnant, are the most vulnerable to mercury's harmful

effects. They should restrict or eliminate certain fish from their

diet, including tuna, tilefish, swordfish, shark, king mackerel,

grouper and fish caught in any waters that are subject to a mercury

advisory. Women with elevated mercury levels should begin avoiding or

restricting their consumption of mercury-laden fish as much as a year

before they become pregnant. (For more, see our guide to mercury

levels in fish.)

 

Restrict Your Portions

 

In general, a woman who is pregnant or is likely to get pregnant

should eat no more than two cans of light tuna per week, or 2/3 of a

can per week of white albacore tuna if she wants to be sure to stay

below the EPA's level of concern for mercury. Keep in mind that the

amount of mercury in a single can varies depending on where the tuna

was caught. Albacore or solid white tuna is most likely to have

higher concentrations, and chunk light tuna, lower concentrations.

 

Raw tuna and other sushi fish are also something to watch out for.

Often the apex predators of the food chain, these fish tend to be

high in mercury. Whenever possible, avoid sushi choices that are

highest in mercury, using this list as a guide.

 

Since children get most of their mercury from canned tuna, it is

important for parents to limit their children's consumption to less

than one ounce of canned light tuna for every 12 pounds of body

weight per week, in order to stay below the level of mercury the EPA

considers safe. That means that a child who weighs 36 pounds should

not eat more than 3 ounces (half a standard-sized can of chunk light

tuna) per week. Children should avoid albacore or white tuna because

the levels of mercury are higher.

 

Check Your Mercury Level

 

To obtain a quick estimate of the amount of mercury currently in your

blood, use our Mercury Calculator. For a more accurate reading, you

can request a blood mercury test from your physician. Women with a

high blood mercury level who are planning to start a family may

decide to postpone pregnancy for a few months until levels drop;

often this occurs over a three to six month time frame.

 

Stay Informed

 

By law the Environmental Protection Agency is obligated to require

power plants to cut roughly 90 percent of their emissions of mercury

and other toxic pollution by 2008. Instead, in March 2005 the agency

let polluters off the hook, requiring much smaller reductions and

giving electric companies more than two decades to accomplish them.

What's more, the agency essentially allowed polluting companies to do

nothing for the next 12 years. To learn about opportunities to

participate in decision-making on this and other environmental and

health issues, join NRDC's Earth Activist Network.

 

Another way you can learn about and avoid mercury risks is to urge

your grocery stores, fish markets and restaurants to label fish

accurately and advise consumers about the dangers of mercury in the

fish they sell. And be sure to read and print NRDC's mercury guides

and to check the mercury calculator.

 

 

 

 

 

 

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