416 



if useful elements of the environment are to be increased. The normal relation- 

 ships among the climates, soils, fauna, and flora that produced the environment 

 invaded by modern man have scarcely begun to be studied — as they must be if 

 man is not to boggle land management. The factors limiting fungus plant dis- 

 eases, and destructive insects such as the locust hordes that ravage Central and 

 South America, also need to be known in order that these numbers may be held 

 as lovs^ as is desirable." 



Thus, as early as 1946 and inereasinorly thereafter, students of 

 ecology were publicly expressing c/)ncern over the impact of pesticides 

 on the environment. They showed awareness of the wide differences in 

 sensitivity^ of various species to toxic pesticides. They recognized the 

 wide variables in sensitivity reflecting differences in the carrier 

 medium, wind, temperature, light and shade, duration of exposure, 

 maturity of victim, and other factors. These preliminary data, how- 

 ever, were only a beginning. It was not enough to count carcasses of 

 dead wildlife. The researches needed to go further: to show the intri- 

 cate and subtle ways in which long-lasting pesticides spread into the 

 natural enviroimient and along food chains to cause lessened fertility 

 of valuable SDecies and reduced bioi^roduction for years after the ini- 

 tial api)lication. Overgenerous and needless dissemination of these 

 chemicals caused damage in nature uncompensated for by any advan- 

 tage from their excessive use. 



In the field of medicine, the complexity of responses of the human 

 organism to organic poisons and drugs was beginning to be recognized 

 also. The differences in response as between acute reacting to signifi- 

 cant dosages, and the protracted chronic responses to trace quantities 

 were gradually recognized also. However, these considerations were 

 not brought out in the 1946-47 hearings. 



Medical, interest in human response to insecticide toxicity 



The earliest experience with DDT suggested that it was not harmful 

 to man. Medical attention was focused, instead, on the profound effect 

 that the potent new insecticide had on disease-carrying insects. For 

 example, one physician in 1947 proposed that an inexpensive way of 

 distributing the powder was to throw it on the floors of public build- 

 ings where traffic is heaviest so that it would be tracked about. This 

 means of distribution, he said, was "exceedingly effective in reducing 

 the living fly population in that building." ^* 



A Department of Agriculture publication in 1960 commented 

 that "* * * this insecticide has been applied as a 10-percent dust inside 

 the clothes of hundreds of millions of men, women, and children by 

 military and public health officials, and has been applied as residual 

 sprays in as many homes without one known case of serious toxic effects 

 to individuals exposed to such intimate insect control practices." ^^ 

 On the other hand, in 1963, DDT was reported to be "cancer produc- 

 ing according to presently available evidence." It had been "incrimi- 

 nated * * * in the production of benign and malignant tumors of the 

 liver, cancers of the lung, and leukemias." ^® These were suggestive of 

 long-term effects; the short-term etlects were generally agreed to be 



33 Ibid., p. 159. 



3* .TAMA (May 24, 1947, vol. 134, No. 4), p. 408. 



»= E. F. Knipiing. Nature and Fate of Chemical Applied to Soils, Plants, and Anima].<5. 

 (Affrlcultural Research Services. U.S. Department of Agriculture. September 1960), p. 28. 



3« Statement by Dr. W. C. ITueper, National Cancer Institute, National Institutes of 

 Health. "Toxic and Carcinofrenle Hazards to the Human Population from Pesticides and 

 Pesticide Residues:" In Interagency Coordination In Environmental Hazards (Pesticides). 

 Hearings • * ♦ op. clt., pp. 706-707. 



