certain conditions, The reaction produces 2,2-bis(p-chlorophenyl)-1,1 -dichloroethylene 
(DDE) as follows: 
| 
Oe 
| Ul 
CCl CCL, 
DDT DDE 
Fleck (7) found ultraviolet light to catalyzethe decomposition of DDT. In the presence 
of air, one of the decomposition products is 4,4'-dichlorobenzophenone, When air is | 
absent, 2,3-dichloro-1,1,4,4-tetrakis-(p-chlorophenyl)-2-butene is formed. This com- 
pound, through subsequent oxidation, may be converted into 4,4'dichlorobenzophenone, 
Thus: 
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at) a€_» 
UV Light Noy 
Air Absent oe 
y 
fo) 
In mammals 2,2-bis(p-chlorophenyl) acetic acid (DDA) has been identified and 
shown to be excreted in the feces and urine. The mechanism of formation of DDA is 
believed to be an initial dehydrochlorination to DDE, which is then hydrolyzed to DDA, 
as follows: 
Mattson, et al. (14) found both DDT and DDE in all but 2 of about 50 samples of 
human fat. DDE represented 39-86 percent of the total. Walker, et al. (18), ina study of 
meals purchased in restaurants, found DDT and DDE to be present, at low levels, in 
every sample taken. 
The only metabolite present in insects in any significant quantity is DDE, and no 
evidence of conversion to DDA has been found, Little is known about the fate of DDT in 
soil, 
106 
