Document Ev2KnLvN4EkwJ6dDZZqE5X8jL

NATIONAL LEAD Environmental Health Department W. L. MANN Manager Dr. J. F. Cole, Sc. D. Director, Environmental Health Lead Industries Association 292 Madison Avenue New York, New York 10017 October 11, 1971 Dear Jerry: Re: VITA - Identification of Lead in Paint Our technical people have reviewed the Sayre-Wilson rapid screening technique for lead in paint, as proposed by VITA (Volunteers for International Technical Assistance), and offer the following comments: 1. The test is nonspecific in nature because not only lead but also mercury, copper, bismuth, iron5chromium, cobalt and nickel would yield dark stains when exposed to sodium sul fide solution. Mercury compounds are used as fungicides in paint and some of the other elements which form dark colored sulfides could be present as coloring pigments, as metalloorganic compounds added as drying accelerators, or as contami nants . 2. The response of lead (or other cations which form dark colored sulfides) to the spot test reagent would vary in intensity depending on the nature and the age of the paint film, e. g., a latex paint film might be wet more easily by the sodium sul fide solution than an oil-based paint film. Incidentally, there probably would not be much variation in intensity of reaction with the spot test reagent because of differences in the lead compound used in the paint except that lead chromate could yield both lead sulfide and chromium sulfide. At best, this test could be used as a screening test to determine those paint films which might contain lead as a component. Even for this purpose, the test has a drawback of possibly not giving a posi tive test for lead if the paint is not wet by the aqueous sodium sulfide reagent. I trust the foregoing will be of assistance to VITA in their evaluation of the proposed spot test. We are not aware of any similar spot test that would provide the type of specific information being sought. WLM:cd National Lead Company, 111 Broadway, New. truly,