What Makes Mercury So Harmful to the Body?

[wasteofo2]

Today in Chemistry my teacher was talking about Mercury, and said that it was bad because your thoughts and nerve-impulses are electrical, and that if you have a lot of spare metal floating around your body the signals get all messed up. I asked "What about Iron, that's a critical component of our blood", and he explained that away because the Iron is in your red blood cells, not just floating around. But it still doesn't seem to make sense that Mercury should be so harmful to you. I mean, calcium, sodium and potassium are technically kinds of metals, and we eat those all the time. No one ever warns people not to touch copper or gold or silver etc., and those are more traditional metals. There has to be some other kind of reason that Mercury is so bad for you besides just being a metal.

Does anyone have any idea why?

 

[dav2008]

Just doing a little internet search:

Elemental, liquid mercury is slightly toxic, while its vapor, compounds and salts are highly toxic and have been implicated as causing brain and liver damage when ingested, inhaled or contacted. For this reason (along with exaggeration of the actual risk in the media), most thermometers now use pigmented alcohol instead of mercury, though some medical thermometers still use mercury for reasons of accuracy.

The main dangers associated with elemental mercury are that at STP, mercury tends to oxidize forming mercury (II) oxide, and that if dropped or disturbed, mercury will form microscopic drops, increasing its surface area dramatically.

Even though it is far less toxic than its compounds, elemental mercury still poses significant environmental pollution and remediation problems due to the fact that mercury forms organic compounds inside of living organisms. Methyl mercury works its way up the food chain, reaching high concentrations among populations of some species such as tuna. Mercury poisoning in humans will result from persistent consumption of tainted foodstuffs.

One of the most dangerous mercury compounds, dimethylmercury, is so toxic that even a few microliters spilled on the skin can cause death.

Mercury is a bioaccumulative toxin that is easily absorbed through the skin, respiratory and gastrointestinal tissues. Minamata disease is a form of mercury poisoning. Mercury attacks the central nervous system and adversely affects the mouth, gums, and teeth. High exposure over long periods of time will result in brain damage and ultimately death. It can pose a major health risk to the unborn fetus. Air saturated with mercury vapor at room temperature is at a concentration many times the toxic level, despite the high boiling point (the danger is increased at higher temperatures).

Mercury should therefore be handled with great care. Containers of mercury need to be covered securely to avoid spillage and evaporation. Heating of mercury or mercury compounds should always be done under a well-ventilated, filtered hood. Additionally, some oxides can decompose into elemental mercury, which immediately evaporates and may not be apparent.

I guess that doesn't give any specifics but that might help

 

[Pyrovus]

Mercury has a rather high affinity for sulphur, and tends to react with sulphur-containing organic compounds like this: Hg + 2RSH -> R-S-Hg-S-R +2H+ +2e-. As all enzymes contain SH groups, addition of mercury will hence join onto them and alter their shape, rendering them useless. As a result of this, mercury will wreak havoc on all metabolic processes, as many of the enzymes required to bring them about will have been damaged.

 

[Chronos]

Mercury rips your liver to shreads. You can live on liver, but, you can't live without a liver.

 

[Phobos]

As mentioned, mercury bioaccumulates in vital organs and messes up metabolic processes. (sounds like your teacher was wrong)

Here's a technical link...
http://www.nap.edu/nap-cgi/skimit.cgi?isbn=0309071402&chap=31-71

This link may be a bit alarmist, but it seems to have some valid tech info too (agrees with what Pyrovus said about SH compounds)...
http://www.hbci.com/~wenonah/hydro/hg.htm

 

[dangavdan]

Hi i was wondering why high levels of mercury are not toxic to fish. also chlorine is a poisonous gas which combines with sodium to produce edible table salt. Perhaps mercury is combined with some other element to make it non poisonous. it seems to me that even a small bit of mercury would kill you if it were that bad. I am starting to believe that everything that is protrayed as bad is actually very good for you, the problem is that big companies don't make money unless you get it in a bottle from them so theyl tell you anything to make you unhappy and then give you a wonder pill.

 

[Ygggdrasil]

Hi i was wondering why high levels of mercury are not toxic to fish. also chlorine is a poisonous gas which combines with sodium to produce edible table salt. Perhaps mercury is combined with some other element to make it non poisonous. it seems to me that even a small bit of mercury would kill you if it were that bad. I am starting to believe that everything that is protrayed as bad is actually very good for you, the problem is that big companies don't make money unless you get it in a bottle from them so theyl tell you anything to make you unhappy and then give you a wonder pill.

The chemical properties of a compound change greatly when you change their electronic state. This is one of the basic principles of chemistry and something they teach in every introductory chemistry class. Table salt is not made of chlorine; it is made of chloride ions. The difference between the reactivity of Cl₂ (chlorine) and Cl^- (chloride) is huge.

Now, interestingly elemental mercury is not so bad for you. Mercury does, however, get its toxicity when it reacts with organic substances in the body to form organomercury compounds (like dimethylmercury). Unfortunately, there are many enzymes and substances in the body that can convert elemental mercury into organomercury compounds.

The idea, however, that you can react a toxin with another substance to neutralize the toxin is a good one, however. For example, in many cases, you can try to treat heavy metal poisoning by ingesting a compound that chelates (binds and wraps up) the heavy metal ions so that they can be removed from the body. This approach can be used in response to mercury poisoning. The chelating agent contains thiol groups to take advantage of mercury's affinity toward sulfur. In essence, you are trying to get the mercury to bind to the thiol groups on the chelating agent instead of sulfurs in the body.

 

[dangavdan]

why then when the recommended daily allowance of mercury is consumed does it not turn to dimethylmercury. how can fish function with such high levels of mercury. for the mercury to become dimethylmercury it must briefly become an ion. perhaps depending on what molecules are in the cells ie. depending on your diet, it will influence the compound to which the mercury will bond to or become and therefor neutralizing the element.

 

[dangavdan]

for the mercury to become dimethylmercury it must briefly become an ion, perhaps the molecules within your cells ie. depending on your diet, will determine which compound the mercury will make.

 

[kldickson]

The problem with dimethylmercury is that it complexes to cysteine and that it is eliminated from the body slowly. Find information on Minamata disease if you want to know what happens to the body.

Specifically, it's a neurotoxin.

 

[kldickson]

Today in Chemistry my teacher was talking about Mercury, and said that it was bad because your thoughts and nerve-impulses are electrical, and that if you have a lot of spare metal floating around your body the signals get all messed up. I asked "What about Iron, that's a critical component of our blood", and he explained that away because the Iron is in your red blood cells, not just floating around. But it still doesn't seem to make sense that Mercury should be so harmful to you. I mean, calcium, sodium and potassium are technically kinds of metals, and we eat those all the time. No one ever warns people not to touch copper or gold or silver etc., and those are more traditional metals. There has to be some other kind of reason that Mercury is so bad for you besides just being a metal.

Does anyone have any idea why?

This is messed up. Metals don't affect electrical signals this way. Calcium, sodium, and potassium exist as ions in your neurons and between your synapses.

Your chemistry professor needs to read a biology textbook.

 

[dangavdan]

yes but the minamata case is one which is in extreme. if i saw cats and dogs comiting suicide and birds falling out of the sky id be worried. the chisso corporation dumped 27 tonnes of mercury into the minamta bay, where in the world today is there such dumping going on. My body will tell me anyway if I am taking too much. tuna seriously helps my brain to concentrate, so i can be aware of the dangers.

Wouldnt also a healthy diet with plenty of antioxidants help to rid of excess metals.

 

[mazinse]

This is messed up. Metals don't affect electrical signals this way. Calcium, sodium, and potassium exist as ions in your neurons and between your synapses.

Your chemistry professor needs to read a biology textbook.

yeah i was wondering about too. Tissues usually have ways of regulating these things, and it's pretty specific. Something is up with this teacher