Document ZBLy3ejM0BeX1oKV2EG5dVdE8
September 15, 193?
Mr. Charles A* Marllee Consumers Union of United States, Jnc. 55 Van Dam Street I-lew York
Dear Mr. Marliest,
.
I have your letter of
September 8th In which you have raised a number
of questions about the possibility of our carrying
out certain analyses for your organisation. I am
familiar with the general character of ycur work but
I regret very much that we shall not be in position
to do any regular work of the type you suggest.
However# in as much as we have done and are continuing
to do a fair amount of work which m y be of ultimate
interest to you# it seems worth while to explain our
situation, and to reply briefly to the questions raised
as to our facilities *
.
This laboratory is not a testing laboratory In any sense in as much as it is one of the investigative laboratories of the Medical School of the Universety of Cincinnati. Our principal work is concerned with the study of major problems in industrial hygiene, and that portion of the work in which I am chiefly concerned has had to do with the study of lead absorption both in industry and in the general population, and lead poisoning both in and out of industry. Hy reason of our academic and public responsibilities in a municipal university, we are not in a position to do commercial work or confidential work, That is to say, studies which we make are primarily for the purpose of obtaining information for publication through the normal scientific channels. We do not engage in any work except with the understanding that the results are to be published when and where we see fit* Thus most of the information which we obtain would be made available
be you or to other Interested persons in the n o m a ! course of events. We have been making observations on the lead content of food material and on the average dally lead ingestion of normal average Individuals in the American population with the idea of obtaining a substantially cross-psectibnal picture. This work has continued over a period of years and we have thus accumulated a siseable mass of data, some of which has been published and some of
-2
which is awaiting early publication* Our facilities
for this work are* perhaps* as complete as those to be
found anywhere in the world* The methods which we
employ include a spectrographic method devised and
standardised by one of the members of the laboratory
staff* (This method is applicable not only to the
quantitative estimation of lead with a negligible
experimental error* but has also been .extended to
the quantitative determination of a number of other
v
hoavy metals*) These methods have been described
In the literature together with the limits of sensitivity
and aecurady by my associate Jacob Cholak* We are also
using a modification of the Pisoher-Leopoldi ^Dlthlzone**
method which lias been very carefully checked step by
step* and which gives results comparable in accuracy
with those obtained by the spectrographic method*
For larger samples with a larger lead content we have
used a chemical method* the details of which are
described in the Journal of Industrial Hygiene for
September 1933* ;Ti|:h|eg ||c'^omparative sens^i|tpipvi|t!yi|| asfnf|d n
worked out in detail in a considerable series of
parallel analyses on a. variety of materials* The
article containing these data will appear in an early
number of the Analytical Edition of Industrial and
Engineering Chemistry*
:
Toisumarize briefly the accuracy
of these three methods* it should be said that the
spectrographic method yields an error of approximately
*01 rags* over the range of values from *01 to *5 mgs*
in the sample* The sensitivity of the method is much
greater than this* however* and it is possible to deal
with quantities of lead of an order of magnitude con
siderably less than
The difchizcne method
has a slightly smaller error in dealing with quantities
of lead of the magnitu.de specified above* but one can
not work with quantities less than *001 mgs* per sample.
The chemical method which we have used has a mean loss
of approximately 0* 07 mgs. per sample by virtue of the
large number of steps involved in the chemical separations.
This loss is substantially constant* This method is*
therefore* quite serviceable in dealing with quantities
of lead above 0*2 mgs* per sample. Actually in recent
months we have largely discontinued the use of the chemical
method since the dithlsons method lends Itself satisfactorily
to the determination of any quantity above 001 mgs. per
sample* since suitable aliquots can always be employed for
the final determinations*
Vie have done lead analyses on practically all types of biological material, and at the present time we are carrying out a series of studies whibh involve the analysis of all types of food as well as animal tissues
Despite what I have said about our
inability to undertake any regular work for your or
ganization both by reason of the nature of the work
as well as the nature and magnitude of our own work*
I wish to assure you that I am quite sympathetic
with the purpose of your undertaking* Therefore* if
we can be of assistance to you in specific instances,
we shall be glad to do so*
'
.;
* Very truly yours*:
EAKjis
'
' ` ' lE b e r T T T lto n o e T ^ D *
^ 0015115