AW: AW: [ RadSafe ] TMI - reported "metallic taste"
Jim_Hardeman at dnr.state.ga.us
Wed Feb 15 12:43:05 CST 2006
Thanks for the reply ... and I agree that you adequately circumscribed the biological processes known to produce mercaptanes <grin> I see little possibility that anyone on the list could be the least bit offended.
You're right ... people who live next to paper plants often don't consciously smell the odors that easily offend visitors ... whether from olfactory fatigue, or they just "got used to it". But I wish I have a nickel (or should I say 0.05 euro?) for every time I've mentioned the smell to someone who works at a paper plant and gotten the "what smell?" response.
After all the discussion on this subject ... it probably does all come down to the power of suggestion. If you ask somebody in a situation like TMI "do you have a metallic taste in your mouth?" I would venture to say that most of the time, the answer will be "yes, now that you mention it".
My $0.02 worth for today ...
>>> Franz Schönhofer <franz.schoenhofer at chello.at> 2/15/2006 13:32:12 >>>
Thank you for reminding me to my early twenties, when I used to work in
Swedish paper- and cellulose mills in the area south of Sundsvall and in
Umea during summer time in order to earn money to continue my studies in
chemistry. Fortunately "our" cellulose factory south of Sundsvall was based
on the "sulfite"-process, which means that it used sodium sulphite to
dissolve lignite to leave the cellulose fibres almost intact. Going north
from Sundsvall just a few kilometers (I do not write "miles", because a
Swedish "mile" means ten kilometers) we could smell the next cellulose
factories, using the so called "sulphate process" producing the
"Kraft-cellulose". The same was true to the town of Umea, where I worked in
the paper-pulp factory within city limits and the sulphate factory was
situated well out of town, where the wind would blow all the mercaptanes out
to the Gulf of Bothnia and I can confirm that it did not reach the town of
Vaasa across the gulf in Finland.
Back to radiation protection and TMI: Hydrogen sulfide is not only a
nuisance to smell, but it is poisonous. The sulfur compounds called
"mercaptanes" are easily smelled in extreme dilution or in other words tens
of kilometers away from the cellulose plant. They are also formed in the
digestion tract of humans by the digestion of amino acids, which contain
sulfur. For instance beans are well known to produce such gases, which might
be an annoyance for people who stay close to the digesting one. I hope that
I have now politely enough circumscribed this biological process that it may
pass the approval process my contributions to RADSAFE are subject to since a
few weeks. I also hope that I have not offended anybody, who thinks that
four-letter words are unexcusable, but...... (continuation available on
personal request and not to the list).
Having this experience of smelling (and I can confirm that people living in
these areas did not consciously smell it!) I personally cannot confirm that
the mercaptanes, the sulfides etc. smell or taste "metallic". Probably one
should define "metallic". Using stainless steel cutlery I cannot distinguish
any taste of "metallic" to a "non-taste". I also wonder, how many people in
the vicinity of TMI have ever licked on copper, nickel, iron, molybdenium,
tungsten etc. in order to be able to link their perceived taste to any one
of these or to metals at all. I confess, that I never licked on any of these
metals and therefore could not compare any taste to them.
I think that Bjorn Cedervall's approach makes in several aspects sense,
though I would rather question the scientifically exact approach to call the
smell or taste as "metallic". The persons asked might have been influenced
by the interviewers as put forward on RADSAFE.
PhD, MR iR
> -----Ursprüngliche Nachricht-----
> Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im
> Auftrag von Jim Hardeman
> Gesendet: Dienstag, 14. Februar 2006 21:56
> An: bcradsafers at hotmail.com; radsafe at radlab.nl
> Betreff: Re: AW: [ RadSafe ] TMI - reported "metallic taste"
> Bjorn et al. *
> The primary "odor causing" effluents from kraft pulp & paper mills are
> collectively referred to as TRS ... "total reduced sulfur" ... and consist
> primarily of hydrogen sulfide, methyl mercaptan, dimethyl sulfide and
> dimethyl disulfide. A mixture of these compounds can be detected by odor
> in air at concentrations down to 1-2 ppb (parts per billion) or 1,500 -
> 3,000 micrograms per cubic meter. These same compounds, in particular
> hydrogen sulfide and methyl mercaptan, are produced naturally in the human
> mouth by the action of anaerobic bacteria near the back of the tongue
> (where the tongue senses sour, bitter and metallic tastes) ... giving rise
> to "bad breath". From what little information I've been able to find, it's
> likely that for persons who've been subject to chronic TRS exposures (such
> as folks who live near paper plants) olfactory fatigue may have dulled
> their ability to smell TRS compounds, but it is unlikely to have affected
> their ability to taste them. Legal limits on TRS compounds (where they
> exist, and if they were in place in Pennsylvania in 1979) would be far
> above the olfactory / taste threshold ... the most common limit I've seen
> is 10 ppb (15,000 ug/m^3) in any 30 minutes.
> Don't know if this is "THE" answer, but it's a lot more plausible than any
> explanation involving tasting a few femptograms of iodine, or whatever the
> "explanation du jour" is.
> My $0.02 worth ...
> Jim Hardeman
> Jim_Hardeman at dnr.state.ga.us
More information about the RadSafe