Document qkkN6bxq3NDpERn7ReMXOemjG

ISTITUTI CLINICI DI PERFEZIONAMENTO ICA DEL LAVORO "LUIGI DEVOTO'' D ir e t t o r e P r o f . EN &ICG C. VIGLIAMI Prof. Robert A. Kehoe Kettering Laboratory Eden and Bethesda Avenues Cineinnati Ohio 4521Q U. S. A. ,o 20122 -M ILAN O N o v e m b e r 9 1 9 6 7 VIA S. BARNABA. 8 57.60.9 - S8.16.10 Prot. 408/ECV/kw J Dear Bob, Thank you very much for your letter of November 1 and for the results of the analyses of lead in the samples we sent you. I am pleased to see that the values for urine and blood are in good agreement. ^ The results for food, however, show wide discrepancies. I agree that something must be or have been wrong in the analyses. With regard to this, I can add some data which may be of interest to you. The same samples of food and wine which were sent to you were also sent to Dr. K.W. Nelson and analyzed by the American Smelting and Refining Company's Department of Hygiene using the atomic absorption method. The following table shows the results obtained by you, Nelson and ourselves. Sample White flour Maize flour Rice Macaroni Sugar Wine Micrograms Pb per Kilogram Clinica Lavoro Milano " Nelson ASARCO Kehoe Kettering Lab. 100 70 360 , 70 55 1000 ^ 70 ' 50 4OO 80 70 210 r 140 70 ISO Micrograms Pb per Litre 172 146 384 I think that at this point it would be desirable to have further experiments and controls carried out and I suggest that you send us and, if you wish, Nelson, too, samples of food and beverages, and blood and urine, too, if you like, so that we can analyse them for lead. ' I shall be seeing Ken Nelson very shortly at the asbestos meeting in Antigua and 1 shall ask him to send some samples to you and to us. With Nelson we have already exchanged samples of blood and urine in addition to the samples referred to in the above table., and the results were in rather good agreement. So I now look forward to receiving some samples from you. In the meantime, I am enclosing a short description of the analytical method we use. Best regards to you and Mrs. Kehoe from Luisa and myself. Your Prof. Enrico C. Vigliani Enel. LEAD ANALYSIS ON SAMPLES OF ORGANIC MATERIAL AND FOOD Mineralization For liquid samples, 50 ml (for urine or beverages) or 10 ml (for blood) are put in a Kyeldahl flask and mineralized in a sand bath at about 200C with concentrated HNO^. - For solid samples, 10 gr. of a homogeneous sample are taken and mineralized Extraction with dithizone and titration , Resolutionize calcination residues with diluted HC1, bring to boiling point and add hydroxylainine. Pour the solution into a separating funnel; add citric acid and KCN, then alkalinize with XH^ (pH 9-10). Extract t h e i e a d with chloroform-dithizone; eliminate excess dithizone by washing with an alkaline solution containing KCN. 1The Pb-dithizone complex is treated with HC1 %; the dithizone remaining in the chloroform phase is titrated with a lead solution ok known concentration.