Geoscience Reference
In-Depth Information
Fig. 13.5
Proposed model for abiotic reduction in a sorbing sediment system (Wolfe
1989
)
CH
3
O
H
H
3
C
S
C
H
N
O
C
N
CH
3
CH
3
Oxidation
Aldicarb
Reduction
CH
3
O
O
CH
3
O
H
H
3
CS C
H
3
C
S
H
N
O
C
N
H
CH
3
CH
3
CH
3
2-methyl-2methyl thiopropionaldehyde
Aldicarb sulfoxide
+
Oxidation
CH
3
H
3
C
S
C
N
O
CH
3
O
H
CH
3
H
3
C
S
H
N
O
C
N
CH
3
2-methyl-2methyl thiopropionitrile
O
CH
3
Aldicarb sulfone
Fig. 13.6
Redox transformation pathways of aldicarb (Macalady et al.
1986
; Wolfe et al.
1986
)
retention, volatilization, dissolution, photolysis and surface-, chemically, and
biologically induced degradation can affect hydrocarbons in groundwater. Bio-
degradation is a major transformation process of petroleum hydrocarbons.
Both aerobic and anaerobic biological degradation control the persistence of
hydrocarbons in groundwater, such as the n-alkane group. A generalized biodeg-
radation pathway is presented in Fig.
13.7
. The aerobic pathway shows conversion
of an alkane chain to fatty acids, fatty alcohols, and aldehyde and carboxylic acids,
which are then channeled into the central metabolism for subsequent b-oxidation.
