Geoscience Reference
In-Depth Information
Fig. 16.34 Mineralization of [
13
C] toluene to
13
CO
2
(a) coupled to the reduction of AQDS or
humus (b) by enriched Amsterdam petroleum harbor (APH) (a, b) sediments in anaerobic culture
bottles containing phosphate-buffered basal medium supplemented with AQDS (5 mM) or with
highly purified soil humic acids (12 g/L). Uniformly
13
C-labeled toluene was added at an initial
concentration of 100 lM relative to the liquid volume. Unsupplemented controls were prepared
in the same manner but without AQDS and humus. All data were corrected relative to the
endogenous
13
C-labeled toluene addition). Data are means and standard
deviations for triplicate incubations in each treatment: d denotes days (Cervantes et al.
2001
).
Reprinted with permission. Copyright American Society for Microbiology
control
(without
media supplemented with AQDS or with humic acid (Fig.
16.34
a). There was
negligible recovery of
13
CO
2
in the endogenous and sterile controls. The con-
version of
13
C-labeled toluene to
13
CO
2
was coupled to an increase in electrons
recovered as AH
2
QDS or as reduced humus (Fig.
16.34
b). However, there was no
toluene reduction in autoclaved sediments. These results indicate that humic
substances may contribute significantly to the transformation of contaminants
under anoxic conditions, by serving as electron acceptors.
