The closely related compound, TDE, is converted to its ethylene derivative in 
mammals. In some insects, however, this conversion does not take place and this lack 
of ability to metabolize TDE may be related to an increased toxicity to such insects. 
Benzene hexachloride has been found, by Sternberg and Kearns (17), to be converted 
to pentachlorocyclohexene by dehydrochlorination. San Antonio (16) isolated a metabolite 
from carrot plants which in some respects appeared similar to this compound, 
The occurrence of metabolites of BHC and DDT in insects has recently been re- 
viewed (3). In soils a fairly rapid loss of BHC takes place, but metabolites and degrada- 
tion products have not been identified. The persistence and breakdown of chlorinated 
hydrocarbon insecticides in different soils has been recently reported (12,13). 
Steps in the degradation of BHC may be as follows: 
He oe: H 
C1 H C1 
Water- 
H foal H Cl Soluble 
CL H . Metabolites 
Cl H 
H CE H a 
C1 H (ea 
Davidow and Radomski (4,5) found heptachlor epoxide as a metabolite of heptachlor 
in animals; this appears to be the first record of epoxidation of a foreign organic com- 
pound in an animal body. Ely, et al. (6) detected heptachlor epoxide in the milk of cows 
fed technical heptachlor, and Gannon and Bigger (9) found it in soil treated with this 
insecticide, 
Cl 4y H Cl 4 H 
eal eal 
@) 
———— 
al roe 
H H H H 
a H cl S HCl 
Heptachlor Heptachlor Epoxide 
Bann, et al. (1) showed the conversion of aldrin to dieldrin, a second example of 
epoxidation, in animals, and showed storage of dieldrin in the fat. This conversion, too, 
has since been found to occur in plants and in soils (9,10). 
Ci H Gal H 
H H H H 
Gal Gil 
——————————— 6) 
Gal 
H Cl = 
Gis Dae aq H & 
Aldrin Dieldrin 
107 
