Environ. Sci. Technol., 41 (21 ), 7209 -7214 , 2007 . 10.1021/es0617744 S0013-936X(06)01774-3
Web Release Date: October 9,2007
Published 2007 American Chemical SocietyWeb Release Date: October 9,
Assessing the Relationship between Extensive Use of Organochlorine Pesticides and Cooling Trend during the Mid-20th Century in the Southeastern United States

and
Air Quality Research Division, Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada, and Meteorological Service of Canada, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada
Received for review July 26, 2006
Revised manuscript received February 13, 2007
Accepted February 19, 2007
Abstract:
In contrast to global warming, temperatures in the southeastern United States have exhibited a decreasing trend of up to 1-2
C over the last century. We investigated the relationship between this cooling trend and the extensive use of organochlorine pesticides-particularly dichloro-diphenyl-trichloroethane (DDT) and toxaphene-in the southeastern U.S. from the mid-1940s through the 1970s. Based on annual use and soil residue estimates, it is shown that enthalpies associated with the endothermic evaporation of pesticides from soil resulted in surface temperature decreases of up to -0.2
C. This is the first study to show the inverse correlation between surface air temperature and pesticide use. These findings highlight the potential contribution of the extensive use of organochlorine pesticides to changes in the surface air temperature, especially in regions of intensive agriculture and pesticide use.
C over the last century. We investigated the relationship between this cooling trend and the extensive use of organochlorine pesticides-particularly dichloro-diphenyl-trichloroethane (DDT) and toxaphene-in the southeastern U.S. from the mid-1940s through the 1970s. Based on annual use and soil residue estimates, it is shown that enthalpies associated with the endothermic evaporation of pesticides from soil resulted in surface temperature decreases of up to -0.2
C. This is the first study to show the inverse correlation between surface air temperature and pesticide use. These findings highlight the potential contribution of the extensive use of organochlorine pesticides to changes in the surface air temperature, especially in regions of intensive agriculture and pesticide use.