Document RpjLkpQxgeZxoq4rzrZRkVbRz
FILE NAME: Johnson & Johnson (JAJ)
DATE: 1975 Feb 28 DOC#: JAJ202
DOCUMENT DESCRIPTION: Letter - Review of CTFA Method for Detection of Asbestos in Talc, with comments
Mr. Ian Sloan
Johnson & Johnson, Ltd.
Southhampton Road
Cosham, Portsmouth, Hants
-
P06 4RL
. '
Great Britain
MAR 3 1975
G. LEE
...
Subject:
Review of CTFA Methodology for the Detection of Asbestos in Talc, as well as, Comments on TPF Methodology____________________ __________
Dear Ian,
r
v
As you can see from the requested attached minutes of the CTFA task force on methodology for the detection of asbestos in talc, we have looked at several methods, but have decided on the following schemes.
Amphibole
x-ray diffraction
(-) N/ Stop
(+)
optical microscopy
+
dispersion staining
fibrous
(+)
Nl/
Fail
Serpentine
(-)
n ]/ Pass
(+) s DTA ---------/ Fail
Pass
The DTA procedure is only specific for serpentine, so we examined a proposed dispersion staining/optical microscope procedure to be used to distinguish between chrysotile and the non-fibrous forms of serpentine. Unfortunately, the results of a round robin (#3) analysis on the optical method were unsuccessful; however, we have never found any ^ serpentine minerals in cosmetic grade talc. You will find
.
AiK
MAI!
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February 28, 1975
in the attached literature a report on a quality control
DTA unit for about $3,600 which can easily detect 1%
chrysotile in talc.
From the literature I received from you the TPF
scheme is evidently:
'
Amphibole
Stop
<-) IR
(+) ^ x-ray diffraction
^ Stop
(-) Pass
V +) optical microscopy
for fibers
(+)
> Fail
Serpentine (chryr.otile)
(-) Stop ^ -
x-ray diffraction
(+) ^ optical microscopy
chrysotile fibers
(+) n I/
Fail
(-) n I/
Pass
We have carefully examined the IR method for amphibole and feel particularly with IR, that it is very dangerous to make a tentative mineral identification of an unknown with :one peak (muscovite, aluminium, silicate (china clay) and pyrophyllite all having interfering bands near 750 cm- , for example). Besides, your scheme indicates that you are going to run an x-ray diffraction scan for serpentine so you might as well look in the same scan for the relevant peaks for amphibole. I feel that the IR method is relevant to amphibole detection in talc only if (a) you really know the talc and are thus performing a quality control check on your own talc and (b) you do not have x-ray diffraction equipment.
A critique of your x-ray diffraction procedure is attached
written by the x-ray diffraction expert at Johnson &
Johnson.
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February 28, 1975
3. I did not receive your optical microscopy procedures for amphibole and chrysotile so cannot make comment.
4. .
We are presently practicing and evaluating the Pooley flotation method so we are not in the position to recommend it at this time. Besides, we feel that a detectability Limit with our two present methods of 0.5% to 1% is reasonable and provides us a safety, margin of 48,300 (see Sivertson report of August 15, 1974). Our major problem with the Pooley procedure is that since one can continually recycle the tailings (concntrate) given enough time, it is possible to arrive at levels of detectability of asbestos in talc in the ppm range - at what stage of recycling do you stop? We really want to exclude concentration tech niques in any proposed analytical procedure and are really looking at this method very quietly so that we will be informed and up-do-date with this area of technology. We want to avoid promotion of this approach.
.. ...I.hope my comments are. helpful- and -.i.-.wi ll ./in/fch..;.fu-tuei\s'/
' ' keep you-informed on methodology development.
` '
Sincerely yours,
'
,,
0 -, F. Robert Rolle
gm Enclosures
cc: Dr. W. R. Dean Mr. G. Lee Dr. A. J. Goudie Dr. W. Nashed Dr. T. Shelley Dr. G. Hildick-Smith
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