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Well, I couldn't tell you if my mouth was opened or closed while working, perhaps sometimes open.
However, one thing assured; regardless of my mouth being closed, my nose was always open.
...And therein lies the problem.
As skin was also exposed to the fumes, and specifically lead-oxide dust, the earlier article raises the debate of the skin absorbtion. Does it or doesn't it?
Mike says not at all.
I always assumed there was some absorbtion, but to what degree???
One of the articles is indicating that lead (in the tested forms) is absorbed by the skin, desorbed by the skin elsewhere in the body, all the while not elevating blood Pb. So as far as the debate goes, this research raises more questions than answers.
While these alternative paths are being discussed; I was also informed that lead was a substance that can cross the physical barrier directly to the brain. In my case, as the exposure was very high and via inhalation of Pb fumes, there was some affect of brain being directly affected from the upper nasal cavities.
Does anyone know anything about this?
Is that possible or not?
And what about lead in the lung tissue?
Is lead absorbed into the blood/body there; Or as Mike suggests, only by ingestion on the way?
That may make sense, but does that mean once Pb reaches the lungs, it remains inert?
What is the story?
ANDREW
----- Original Message -----From: michael circleSent: Sunday, July 17, 2005 11:38 PMSubject: Re: [LeadWorkers] Disappointing NTP info re: skin absorption of leadSir.Did you have your mouth closed while you worked with lead?Any time I worked with lead that had dust I cleaned up the dust with a vacuum cleaner first.As you know Florida is a very warm state. Therefore you sweat a lot, removingmost of the lead from my skin. I am (64) years old with out any health problemsfrom lead.I am aware of the nature of lead problems, but repeat, that lead is safe if you do nottake it in by mouth or nose. I know this first hand.YoursMike Circle----- Original Message -----From: A. FRASER HOBDAYSent: Sunday, July 17, 2005 8:01 AMSubject: Re: [LeadWorkers] Disappointing NTP info re: skin absorption of leadGreetings Mike,I know Liz will be expecting a response to your statement. (...Was it a contrived bait to solicit some action?)Are you serious in your belief; "Unless you take lead in by mouth you will not get lead poisoning."?Many of the cases lead poisoning recorded by LEAD GROUP are by workers inhaling fumes, or dust.Whether the reseacher's particular statistics are correct or not, I don't know.I assume your own experience is a result of well-educated safe handling techniques, as opposed to not being informed of the true nature of your blood testing.My own experience was the victim of the latter, causing me to suffer the permanent consequences of massive lead poisoning without receiving medical treatment. This was via inhalation of lead-oxide in a metalurgical lab while gold assaying.In my own research of lead poisoning cases, relatively few were caused by lead by mouth and ingestion.From the article below, we learn of some of the relationship between skin lead absorbtion and perhaps desorbtion via sweat. One would also have to wonder if the increased sweat attributed to working conditions in metallurgical labs and smelter environments also significantly increases absorbtion.However Mike and others, if you wish to hear from someone about lead poisoning who has worked with lead and not just a lead researcher, you are certainly at the right place here @ "leadworkers..." ;)It is a reasonable query from Mike's own experienced perspective.What is all the hyperbole about lead poisoning?...What would you like to know?A. Fraser Hobday (Andrew)
----- Original Message -----From: michael circleSent: Sunday, July 17, 2005 4:44 AMSubject: Re: [LeadWorkers] Disappointing NTP info re: skin absorption of leadI must say that after reading this last e-mail, I find it a joke.For (25) years I handled over 500,000 Lbs. a year of lead in all forms exceptliquid and never was found to have lead poisoning. I was tested every year.Unless you take lead in by mouth you will not get lead poisoning.Maybe if the lab tech. worked with lead they would get more first hand info.I look forward to hearing from some one who worked with lead an not justlab worker or some one who has not had hands on experience.Mike Circle----- Original Message -----From: egroup@...Sent: Friday, July 15, 2005 5:38 PMSubject: [LeadWorkers] Disappointing NTP info re: skin absorption of leadThe four page factsheet "Lead and Lead Compounds: Reasonably Anticipated to
be Human Carcinogens" at
http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s101lead.pdf from the
Report on Carcinogens, Eleventh Edition; U.S. Department of Health and Human
Services, Public Health Service, National Toxicology Program [NTP], released
January 31, 2005, is packed with useful info but disappointingly states:
"Environmental exposure to lead results in its absorption into the body via
inhalation (with approximately 30% to 50% of the inhaled dose absorbed into
the bloodstream), via ingestion (with approximately 8% to 15% of the
ingested dose absorbed into the bloodstream) and, to a limited extent,
through the skin. ...
"The most common route of occupational exposure to lead is inhalation of
lead fumes or lead-laden dusts in air and absorption of lead through the
respiratory system. Lead also may be ingested and absorbed via the
gastrointestinal tract (Bress and Bidanset 1991, Stauber et al. 1994)."
Thus implying both that skin absorption of lead is limited and omitting it
altogether (though including the references to skin absorption) in relation
to occupational exposure. After reviewing the limited literature available,
I believe the factsheet should have stated something like:
"Environmental exposure to lead results in its absorption into the body via
inhalation (with approximately 30% to 50% of the inhaled dose absorbed into
the bloodstream), via ingestion (with approximately 8% to 15% of the
ingested dose absorbed into the bloodstream) and through the skin (Bress
and Bidanset 1991) although skin-absorbed lead may remain undetected if only
blood lead measurements are used to assess exposure (Stauber et al. 1994).
"The most common route of occupational exposure to lead is inhalation of
lead fumes or lead-laden dusts in air and absorption of lead through the
respiratory system. Lead also may be ingested and absorbed via the
gastrointestinal tract and significant amounts of inorganic lead compounds
can be absorbed via the skin (Sun et al. 2002) especially if the skin is
sweaty (Lilley et al. 1988)."
I have emailed the NTP via their website
[http://ntp.niehs.nih.gov/ntpweb/index.cfm?objectid=720166E6-BDB7-CEBA-F0032
407A834B400] asking whether such important changes could be incorporated
into a revised version of the factsheet or a future publication and
requesting that they let me know which they decide to do.
I also proposed that the National Institutes of Health (NIH) fund
further research into this issue especially since the health impacts of
skin-absorbed lead are virtually unknown. I know that Professor Brian Gulson
who co-authored the Stauber et al 1994 study has prepared a proposal for
further skin research and he can be contacted at
bgulson@... but I wondered if other LeadNetters know of
other skin research proposals and could a) support my call for a revision of
the NTP lead factsheet and b) propose that other skin researchers be funded.
The relevant abstracts [and their web addresses] follow:
Sci Total Environ. 1988 Oct 15;76(2-3):267-78.
The use of sweat to monitor lead absorption through the skin.
Lilley SG, Florence TM, Stauber JL.
CSIRO Division of Fuel Technology, NSW, Australia.
[Source:
www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3238
426&dopt=Abstract]
It is usually assumed that lead can be absorbed through the skin only
if it is present as an organolead compound such as tetraethyllead or lead
naphthanate. It has been found, however, that finely-powdered lead metal or
lead nitrate solution placed on the skin results in rapid absorption of
lead, and transport of the metal around the body. The absorbed lead appears
in sweat and saliva, but not in blood or urine. The application of 6 mg of
lead as 0.5 M lead nitrate to the left arm resulted in an increase in lead
concentration in pilocarpine-induced iontophoresis sweat samples taken from
the right arm, from an initial value of 15-25 micrograms Pbl-1 to greater
than 300 micrograms Pbl-1 after 2 days. Saliva lead increased from 2.5 to 15
micrograms Pbl-1 in the same period. The rate of lead absorption through the
skin increases with increased sweating of the skin. Since no measurable
increase in blood lead has been found, the lead must be transported in the
plasma and rapidly concentrated into the extracellular fluid pool (sweat and
saliva), without significant uptake by the erythrocytes, and with a very low
transient concentration in the plasma. Workers occupationally exposed to
lead have extremely high levels of lead in sweat even though their lead in
blood is only moderately elevated. Lead absorbed through the skin may be
eliminated via sweat and other extracellular fluids, and hence not be as
great a health hazard as ingested lead, but this will need to be proved by
further studies.
PMID: 3238426 [PubMed - indexed for MEDLINE]
[end of abstract]
[start of next abstract]
Vet Hum Toxicol. 1991 Jun;33(3):212-4.
Percutaneous in vivo and in vitro absorption of lead.
Bress WC, Bidanset JH.
[Source:
www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1858
297&dopt=Abstract]
Vermont Department of Health, Division of Environmental Health, Burlington
05402.
Diffusion tubes were used to measure the degree of in vitro penetration of
tetrabutyl lead, lead naphthanate, lead nuolate, lead acetate and lead oxide
in excised guinea pig skin and human skin from autopsy. Tetrabutyl lead
demonstrated the greatest penetration in skin from both guinea pig and man.
Lead nuolate, lead naphthanate and lead acetate followed in descending order
in the human tissue. A similar pattern occurred with guinea pig skin in most
cases. There were no measurable amounts of lead oxide absorbed in either
species. In vivo absorption was measured by applying 300 mg/kg tetrabutyl
lead, lead nuolate, lead naphthanate or lead oxide to the shaved backs of
guinea pigs for 7 d under occluded wrappings. Tetrabutyl lead was present in
tissues in the highest quantities. Lead nuolate was present in greater
amounts than lead naphthanate in the liver and kidneys. Lead acetate was the
most poorly absorbed with the exception of lead oxide which demonstrated no
absorption.
PMID: 1858297 [PubMed - indexed for MEDLINE]
[end of abstract]
[start of next abstract]
AIHA J (Fairfax, Va). 2002 Sep-Oct;63(5):641-6.
Percutaneous absorption of inorganic lead compounds.
Sun CC, Wong TT, Hwang YH, Chao KY, Jee SH, Wang JD.
Department of Dermatology, National Taiwan University Hospital, Taipei,
Taiwan.
[Source:
www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&
list_uids=12529920]
The objective of this study was to determine percutaneous absorption of lead
compounds, including lead sulfate, lead oxide, lead powder, and lead
stearate. The lead content on the skin surface of 10 lead-battery workers
was measured by the method of skin stripping, and urinary lead content of
rats was measured with epicutaneous application of four lead compounds: lead
sulfate, lead oxide, lead powder, and lead stearate. There were significant
amounts of lead on the 9th and 10th skin strippings of the dorsal hand and
the back of lead workers. The amount of lead on the dorsal hand was
significantly correlated with the amount in the blood (n = 10, r 2 = 0.66, p
< 0.05, linear regression). In rats, after lead compounds were applied for
12 days, total lead amount in urine significantly increased to 146.0 +/- 6.4
ng (SD) for lead stearate, 123.1 +/- 7.2 ng for lead sulfate, 115.9 +/- 5.3
ng for lead oxide, 47.8 +/- 6.9 ng for lead powder, and 10.3 ng for the
control, which indicated significant skin absorption. It was concluded that
significant amounts of inorganic lead compounds can be absorbed through the
skin, and skin protection in lead-working or any contaminated environment
should be carefully considered.
PMID: 12529920 [PubMed - indexed for MEDLINE]
[end of abstract]
[start of next abstract]
Sci Total Environ. 1994 May 2;145(1-2):55-70. Related Articles, Links
Percutaneous absorption of inorganic lead compounds.
Stauber JL, Florence TM, Gulson BL, Dale LS.
CSIRO Centre for Advanced Analytical Chemistry, Menai, NSW, Australia.
In vivo experiments with the stable lead isotope, 204Pb, have confirmed that
inorganic lead compounds can be absorbed through the skin. Three different
analytical techniques--thermal ionization mass spectrometry, inductively
coupled plasma mass spectrometry and anodic stripping voltammetry--showed
that lead, as lead nitrate or lead acetate, was rapidly absorbed through the
skin and detectable in sweat, blood and urine within 6 h of skin
application. Of the 4.4 mg of lead applied to the skin in one experiment,
1.3 mg was absorbed within 24 h. Initial rapid uptake was probably via sweat
glands and hair follicles, followed by slower absorption via the
transepidermal route. While increases in 204Pb concentration and abundance
were observed, no increase in total lead in blood or urine was found. It is
possible that the physicochemical form of skin-absorbed lead partitions
strongly into extracellular fluid, but has a low affinity for erythrocytes.
There was no significant difference in uptake of lead into erythrocytes (in
vitro) from normal saline, synthetic sweat or sauna sweat. Ultrafiltration
of sweat showed that up to 70% of lead in sweat was associated with > 30,000
MW particles. It is possible that percutaneous absorption of lead could
contribute significantly to lead body burden, particularly from occupational
exposure to lead in dust. Moreover, because lead absorbed through the skin
was only just detectable in blood, and blood lead is the main criterion by
which industry determines exposure, skin-absorbed lead may remain
undetected.
PMID: 8016629 [PubMed - indexed for MEDLINE]
[end of abstract]
Yours Sincerely
Elizabeth O'Brien, Manager, Global Lead Advice & Support Service (GLASS) run
by The LEAD Group Inc.
PO Box 161 Summer Hill NSW 2130 Australia
Ph +612 9716 0132, Freecall within Australia 1800 626 086
Fax +612 9716 9005
Web: www.lead.org.au
Email: egroup@...
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