UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 1027 



Contribution from the Bureau of Chemistry 

 W. G. CAMPBELL, Acting Chief 



Washington, D. C. 



April 17, 1922 



POISONOUS METALS ON SPRAYED FRUITS AND 



VEGETABLES. 



By W. D. Lynch, Assistant Chemist, G. C. McDonnell, Chief, Insecticide and 

 Fungicide Laboratory, and J. K. Haywood, Chief, Miscellaneous Division, Bureau 

 of Chemistry; A. L. Quaintance, Entomologist in Charge, Fruit Investigations, 

 Bureau of Entomology; and M. B. Waite, Pathologist in Charge, Fruit-Disease 

 Investigations, Bureau of Plant Industry.^ 



Purpose of investigation 



Results of previous investigations 

 Experimental work 



CONTENTS. 



Page. I Page. 



1 Results of experimental work IS 



1 Summary 58 



16 Literature cited 58 



PURPOSE OF INVESTIGATION. 



In the spring of 1915 a cooperative study was undertaken in the 

 United States Department of Agriculture to ascertain the amounts 

 of arsenic, lead, and copper remaining on fruits and vegetables 

 treated with poisonous sprays. The spraying was done under the 

 direction of the Bureau of Entomology and the Bureau of Plant 

 Industry, and the chemical work by the Bureau of Chemistry. The 

 plan was to spray various fruit trees and vegetables according to 

 accepted schedules, and also with excessive amounts of material to 

 determine how much of the metals may be present under adverse 

 conditions. In case the investigation showed that poisonous metals 

 remained on the fruit in amounts which might prove injurious to 

 the consumer, the results would constitute a basis for so changing 

 or regulating the spraying schedules as to eliminate this danger. 



RESULTS OF PREVIOUS INVESTIGATIONS. 



Arsenical compounds first appeared as insecticides in the United 

 States (63)^ about 1860, when Paris gi;een was used to check the 



' Credit is due to John G. Fairchild and Wilbur A. Gersdorff for assistance in the analytical work re- 

 ported in this paper. 

 ' Figures in parentheses refer to Literature Cited, pp. 58 to 66. 

 72S38— 22— Bull. 1027 1 



