The
other day I was idly browsing my facebook feed and encountered an
image regarding the presence and safety of mercury in vaccines.
The
image is in two parts; both are satirical. The top half was created
in favor of the anti-vaccination movement declaring that the presence
of mercury in vaccines is dangerous. The bottom section is an equally
sarcastic rebuttal to the former; stating that the original author
has no idea what he is talking about. The image itself is actually
terribly incorrect on a few points; though it does invite a few
interesting question for discussion. What is thimerosal? What is it
for? Does it contain mercury? Is it dangerous? Am I an ignorant
idiot? Let us find the answers for ourselves.
I
will start by going over the image itself first and then digging into
the real meat of the subject. The second section of the image states
“This is how I would normally handle chlorine... but when it is in
the form of table salt, it is completely safe.” True to what is
meant to be implied chlorine is pretty dangerous. Chlorine is gaseous
under normal temperature and pressure; it is irritating to the lungs
at 15 parts per million (ppm) and lethal at 50 ppm. Thus the reason
the scientist is carefully holding that beaker away from his face;
though I do feel the need to comment on his lack of a respirator and
hazmat suit.
The
second half of that statement, regarding table salt, has a few
misleading points. It correctly says that when chlorine is in the
form of table salt, sodium chloride, it is completely safe. In fact,
it is not only completely safe but even necessary for the human body
to survive.
The
reason for this is simple: notice the chemical name of table salt,
sodium chloride. Particularly, notice the 'ide' part of chloride.
Chloride is completely safe for humans; whereas chlorine is deadly.
The difference between the two is small, yet significant. When
chlorine gains an extra electron it has an over all negative charge;
this makes the anion of chlorine, chloride. Anions cannot freely
exist: they must bond with another element to maintain chemical
balance. That negative charge from the extra electron cannot just
hang out by itself. Certain other elements tend to get a positive
charge; sodium is one of these.
There
is an important distinction to make here. Chlorine is not simply
present in table salt; it is in an entirely different form.
Additionally, sodium chloride does not break down into its' base
elements in the human body. If the second author of the image is
correct then mercury must be in a different, safe, form when present
in thimerosal and it must be stable when metabolized in the human
body.
Now
we can dig into what thimerosal actually is. Thimerosal is a compound
used as a preservative in vaccines; it is created by reacting
ethylmercuric chloride with thiosalicylic acid. When present in the
body, especially the bloodstream, thimerosal breaks down back into
thiosalicylate and ethylmercuric chloride.
Thiosalicylate
can be dismissed easily enough. It is not dangerous to the human body
and is only used as a reactant to create other compounds (like
thimerosal) and as a dye. On the other hand ethylmercuric chloride is
quite a bit nastier. You may be thinking, 'Hey, we just talked about
chloride! That stuff is good for us!' This is absolutely correct;
however the important part of this particular molecule is the
ethylmercuric bit. I looked up ethylmercuric chloride on the
website of a scientific chemical supplier. The notable part of the
entry is in the safety and documentation section of the webpage. Out
of the list of warning labels I found H300, H310, and H330 to be of
particular interest. Those abbreviations are the supplier's codes for
hazards: fatal if swallowed, fatal in contact with skin, and fatal if
inhaled, respectivally. The Center for Disease Control states that
ethylmercuric compounds are safe. Out of the two sources here, I
think I would rather trust the one that does not have a vested
interest in proving that ethylmercuric chloride is safe.
Mercury,
in any organic form, is dangerous to the human body. When it is
absorbed into the bloodstream mercury is carried into the brain. Once
there, it wrecks havoc on the nerve cells; causing headaches, memory
loss, sensory impairment, lack of coordination, and death. Naturally
the dose makes the poison here; although many people would rather
avoid the 'mild' symptoms as well.
The
estimated lethal dose (obviously, nobody can really test this
legally) of organic mercuric compounds, such as ethyl mercuric
chloride, is 20 milligrams (0.000705479 oz.). For the average adult
weighing 72 kilograms (157 lbs) the lethal dose is 1,440 milligrams
(0.05 oz.) of mercury. Not something any sane person should want in
their body in any amount.
The
natural reaction upon learning this information is to ask how much
mercury is actually in thimerosal and how much is actually being
injected with vaccines. Checking the Material Safety Data Sheet
(MSDS) for thimerosal tells us that the compound is 49.55% mercury by
weight, a little bit less than half. Finding how much thimerosal is
in a vaccine shot is a rather difficult question to answer as it
happens. Just by browsing the Center for Disease Control and the Food
and Drug Administration websites I found answers ranging from less
than 1 microgram all the way up to 125 micrograms. Other sources
claim amounts around 300 micrograms; some vaccine critics claim as
much as 900 micrograms. My personal opinion is that more mercury is
bad; I would just as soon avoid any amount of it at all. However, the
purpose of this post is not to recommend or discourage the use of
vaccines; only to inform on what thimerosal is and to try and
discourage some bad science.
Finally,
we are ready to answer our questions from earlier. What is
thimerosal? A compound made out of thiosalicylic acid and
ethylmercuric chloride. What is it for? As a preservative in
vaccines. Does it contain mercury? Yes, in the organic form of
ethylmercuric chloride. Is it dangerous? Yes. Am I an ignorant idiot?
We do not know. Perhaps that is a discussion for another time.
Hopefully
I have given you, the reader, a bit more knowledge on the subject.
Thimerosal is indeed not mercury. However it does contain mercury
and, most importantly, breaks down into that same compound in the
human body. Perhaps the original image is correct: knowing a few
basic chemistry concepts before commenting on them is a good idea. I
would like to add that it is a good idea to discuss differences of
opinion with well thought debate rather than a single sentence
captioning a picture. Otherwise, you too run the risk of looking like
an ignorant idiot.
WORKS
CITED
“Thimerosal.”
Hawley's
Condensed Chemical Dictionary. 12Th
ed. 1993. Print.
“Ethylmercuric
Chloride.” Hawley's
Condensed Chemical Dictionary. 12Th
ed. 1993. Print.
“Thiosalicylic
Acid.” Hawley's
Condensed Chemical Dictionary. 12Th
ed. 1993. Print.
Emsley,
John. The
Elements 3rd
ed.
New York: Oxford University Press Inc., 1998. Print.
Newton,
David E. Chemical
Elements: From Carbon to Krypton Vol. 1.
Farmington Hills: UXL, an Imprint of Gale. 1999. Print.
Newton,
David E. Chemical
Elements: From Carbon to Krypton Vol. 2.
Farmington Hills: UXL, an Imprint of Gale. 1999. Print.
Brown,
Theodore L., Lemay, H. Eugene jr., Burson, Bruce E. Chemistry:
The Central Science.
10Th
ed. Upper Saddle River: Peorson Education inc. 2006. Print.
“Ethyl
Mercuric Chloride” Sigma-Aldrich.
Sigma-Aldrich, n.d.
Web. 18 May 2016.
“Thimerosal
in Flu Vaccine” CDC.
Centers for Disease Control and Prevention, n.d.
Web. 18 May 2016.
“Frequently
Asked Questions about Thimerosal.” CDC.
Centers for Disease Control and Prevention, n.d.
Web.
18 May 2016.