Lead white of fine particle size

Srebrenka Bogovic-Zeskoski <fineartinfo [at] rogers__com> writes

>I have been teaching a course on Historical Techniques of the Old
>Masters for a number of years and the use of powdered pigments could
>not be avoided if one was to understand past methodologies, as the
>modern paints are a far cry from what the old masters were using.
>Due to the need to extend their shelf life as well as greater profit
>modern oil paints (regardless of the cost) do contain additives
>which make duplication of certain techniques impossible.
>
>Aware of dangers when using pigments in a powdered form all our
>studio students had to attend a lecture on safety and "no food in
>the studio" was strictly enforced. Making pigments available in
>extremely small amounts (a thimbleful goes very, very far) damaging
>spills, i.e. airborne particles were greatly avoided. The only
>concession made to "modern" material was concerning the lead white.
>When this pigment had to be used it was always made available
>already mixed with oil. The students were cautioned not to touch it
>with their hands and to promptly clean implements as soon as the
>work was done.

It sounds like you are using pretty good precautions.  But there is
one further precaution I always add--to insure that the student is
safe.

As I do for all workers in any country working with lead in any
amount, I suggest they ask their doctors to include blood lead tests
in their regular check ups.  I looked up the recently compiled stats
and the mean average for Canadians in 2007 and 2008 was about 1.35
micrograms/deciliter (ug/dL). Canadians are just a little bit less
contaminated than US citizens.  But if you live in Canada or the US
and your blood lead level is higher than 2 ug/dL, it would be fair
to assume you are getting a bit of lead from somewhere other than
food, water, and standard pollution sources and you need to take
more precautions.

This is also a good advice for students because we do not know the
life styles or histories of the students.  There probably one or two
in each class who already have blood lead levels that are too high.
While there are no statistics on artists, there are many anecdotal
cases of elevated blood lead levels in whole families where an
artist member painted or did ceramic work. The CDC also compiled the
number of elevated blood leads caused by hobbies such as target
shooting.  Two other documented causes are shooting fire works and
refinishing antiques.

The latest studies also show there is no level of lead which does
have adverse effects.  While the low blood lead levels show no overt
symptoms, it is now known children are losing IQ points at all lead
levels no matter how low (1) and adults show higher risk of
mortality from all causes in direct proportion to these low blood
lead levels.(2) This is probably due to subtle effects on blood
pressure, kidney, brain, and other organ function.

The level at which health department in the US intervene when labs
record high blood lead levels has dropped from 25 in the past to 10
ug/dL today. But the CDC recommends that physician get involved when
pregnant women test above 5 ug/dL(3).

And yes, lead can still be used in ceramic glazes in the US and
Canada as long as the producers of the foodware are in a regular lab
testing program to show this lead does not leach into food above
certain levels.  And the workplace in which those ceramics are made,
the US OSHA Lead Standard and the Canadian Standard Respecting Lead
require the employer to have a formal program.  Read these rules.
They require far more precautions than not eating in the studio and
washing up when through work.

However, safety people like myself, are embarrassed that these
occupational lead standards are 30 years out of date.  They do not
require removal of workers from the workplace until their blood lead
levels are at 50 ug/dL, levels that OSHA has said in print in the
Federal Register are no longer considered protective of workers. But
as long as the political climate remains as it is, these laws
probably will not change.

We don't have to wait for better laws.  We can use common sense to
hold our own practices better standards.

Footnotes:

1.  New England Journal of Medicine, Vol.348:1517-1526, Apr. 17,
2003, No.16

2.  Weisskopf, M; Jain, N; Nie, H; Sparrow, D; Schwartz, J; Hu, H.
Bone Lead and Death From All Causes, Cardiovascular Diseases, and
Cancer: The Normative Aging Study.  Epidemiology, 2007; Vol 18,
Issue 5, p S151, and updated in Epidemiology and Prevention in 2009
(2009;12:1056-1064)

3.  See web site of the Association of Occupational and
Environmental Clinics.

<URL:http://www.aoec.org/documents/positions/mmg_final.pdf>

Also cited in the CDC's MMWR, 60(25), July 1, 2010.

Monona Rossol, ACTS
New York NY


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                  Conservation DistList Instance 25:45
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