Document 6wz4e0wKX7rvxj1EJr1MwBZER

city o f JAMES P. DIXON. K. D. COMMISSIONER NORMAN R. INGRAHAM. K. D. DEPUTY COMMISSIONER OWEN B. STUBBEN DEPUTY COMMISSIONER DEPARTMENT OF PUBLIC HEALTH ROOM630 . CITY HALL ANNEX, PHILADELPHIA 7. PA. Division of Air Pollution Control and Environmental Sanitation September 28, 1955 Dr* R. A. Kehoe University of Cincinnati College of Medicine Cincinnati 19, Ohio Dear Dr. Kehoe: An industrial firm in Philadelphia, engaged in electroplating, plates lead and tin on copper wire. The metal source is an anode containing 70$ lead and 30% tin. The tank solution is made up of 20$ fluoboric acid, 5$ boric acid, 20$ lead fluoborate, and 10$ fluoborate. The company plans to make atmospheric tests at this operation for the determination of possible adverse health conditions. We advised the company to test for lead and fluorides. In regard to fluoride analysis, we plan to advise the company to use titrimetry involving thorium nitrate or colorimetric with zirconium-alizarin. For lead analysis, we suggest the colorimetric method with dithizone. We are primarily interested in having your opinion regarding the suitability of the dithizone analysis for lead in the presence of fluorine. If convenient, will you please let us have your opinion in this regard? Very truly yours ML :r N14007 KE 0012311 B. C. Lucas, Assistant Chief Industrial Sanitation Section