associated with low amounts of organochlorine
compounds, including chlorinated hydrocarbons.
Lessons learned about the environmental behavior
and adverse effects of chlorinated hydrocarbons
provide guidance about what to expect for the more
general class of organochlorine compounds. Much
information is available about chlorinated pesticides
such as the DDTs (in this article DDT includes p,p
0 -
and o,p-DDT and the immediate biodegradation and
metabolism products DDE and DDD, see Figure 1)
and PCBs. Thus, DDT and PCBs are used herein as
examples for the larger class of chlorinated
Biphenyl molecule
One example of a
PCB
Simpler chemical
representation of the
same PCB
C
C
C C
C
C
H
C
H
H
H
H
H
H
H
H
H
C C
C
C
C
C
C
C C
C
C
H
C
H
H
H
H
H
H
C C
C
C
C
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
C
CCl 3
o, p′ – DDT
o designates ortho or next to the central carbon atoms
p designates para or across from the central carbon atoms
designates the right hexagonal or phenyl molecule
o, p′ – DDD
o, p′ – DDE
p, p′– DDE
p, p′ – DDD
p, p′ – DDT
H
Cl
C
CHCl 2
H
Cl
C
CCl 2
Cl Cl
Cl Cl
Cl
Cl
Cl
C
CCl 3
H
C
CHCl 2
H
C
CCl 2
′
(B)
Cl
Cl
Cl
Cl
Monochlorobiphenyls
Cl
Cl
Cl
Cl
Cl
Cl
Trichlorobiphenyls
Examples of PCBs
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Tetrachlorobiphenyls
2,4,5-trichlorobiphenyl
Dichlorobiphenyls
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Pentachlorobiphenyls
Hexachlorobiphenyls
Hept-[7], octa-[8], nona-[9]
chlorobiphenyls and the single
decachlorobiphenyl are not as
common in use or in the
environment
Cl
Cl
Cl
Cl
Cl
H Cl
H
C l
Cl
Cl
Cl
Cl
Cl
Cl
Cl H
H
Cl
Cl
Alpha
Gamma
Chlordane
Alpha
Beta
Gamma
Cyclohexane
(C)
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
O
Cl Cl
Cl
Cl
Cl
Cl
Cl Cl
Cl
Cl
Cl
Heptachlor
Hexachlorobenzene
Endrin
Aldrin
Dieldrin
(A)
Figure 1 Chemical structures of (A) polychlorinated biphenyls (PCBs); (B) dichlorodiphenyltrichloroethane (DDT) and the metabolites
dichlorophenyldichloroethane (DDD) and DDE; (C) other chlorinated pesticides. C, carbon atoms; H, hydrogen atom; Cl, chlorine atom.
164 CHLORINATED HYDROCARBONS
compounds, including chlorinated hydrocarbons.
Lessons learned about the environmental behavior
and adverse effects of chlorinated hydrocarbons
provide guidance about what to expect for the more
general class of organochlorine compounds. Much
information is available about chlorinated pesticides
such as the DDTs (in this article DDT includes p,p
0 -
and o,p-DDT and the immediate biodegradation and
metabolism products DDE and DDD, see Figure 1)
and PCBs. Thus, DDT and PCBs are used herein as
examples for the larger class of chlorinated
Biphenyl molecule
One example of a
PCB
Simpler chemical
representation of the
same PCB
C
C
C C
C
C
H
C
H
H
H
H
H
H
H
H
H
C C
C
C
C
C
C
C C
C
C
H
C
H
H
H
H
H
H
C C
C
C
C
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
C
CCl 3
o, p′ – DDT
o designates ortho or next to the central carbon atoms
p designates para or across from the central carbon atoms
designates the right hexagonal or phenyl molecule
o, p′ – DDD
o, p′ – DDE
p, p′– DDE
p, p′ – DDD
p, p′ – DDT
H
Cl
C
CHCl 2
H
Cl
C
CCl 2
Cl Cl
Cl Cl
Cl
Cl
Cl
C
CCl 3
H
C
CHCl 2
H
C
CCl 2
′
(B)
Cl
Cl
Cl
Cl
Monochlorobiphenyls
Cl
Cl
Cl
Cl
Cl
Cl
Trichlorobiphenyls
Examples of PCBs
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Tetrachlorobiphenyls
2,4,5-trichlorobiphenyl
Dichlorobiphenyls
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Pentachlorobiphenyls
Hexachlorobiphenyls
Hept-[7], octa-[8], nona-[9]
chlorobiphenyls and the single
decachlorobiphenyl are not as
common in use or in the
environment
Cl
Cl
Cl
Cl
Cl
H Cl
H
C l
Cl
Cl
Cl
Cl
Cl
Cl
Cl H
H
Cl
Cl
Alpha
Gamma
Chlordane
Alpha
Beta
Gamma
Cyclohexane
(C)
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
O
Cl Cl
Cl
Cl
Cl
Cl
Cl Cl
Cl
Cl
Cl
Heptachlor
Hexachlorobenzene
Endrin
Aldrin
Dieldrin
(A)
Figure 1 Chemical structures of (A) polychlorinated biphenyls (PCBs); (B) dichlorodiphenyltrichloroethane (DDT) and the metabolites
dichlorophenyldichloroethane (DDD) and DDE; (C) other chlorinated pesticides. C, carbon atoms; H, hydrogen atom; Cl, chlorine atom.
164 CHLORINATED HYDROCARBONS