Acetonitrile Extracts
Base/Acid Hydrolysates
2,6DANT
2ADNT
2%
14%
2,4DANT
TNT
24%
35%
4ADNT
58%
2ADNT
16%
4ADNT
51%
2,6DANT
TNT
13%
20%
4ADNT
2,4DANT
41%
2ADNT
20%
49%
4ADNT
31%
2ADNT
26%
2,6DANT
10%
2,4DANT
2ADNT
4ADNT
TNT
17%
38%
36%
42%
2ADNT
4ADNT
37%
20%
Figure 1. Relative quantities of ADNT and DANT isomers in root tissues.
sphere microbes, whereas the quantity of 2ADNT
ond nitro group on the TNT molecule is reduced
exceeded 4ADNT for axenic cultures. Thus, it
to create the DANT only after the ADNT is
could be hypothesized that the greater quantity
bound.
of 4ADNT found in root tissue grown in condi-
The relative quantities of the two ADNT iso-
tions that favor microbial activity is due to the
mers, 2ADNT and 4ADNT, are shown in Figure 1.
uptake of 4ADNT that was already produced
In the plants irrigated with contaminated water,
outside the roots. The predominance of 4ADNT
where the concentrations of explosives were
over 2ADNT also accounts for the greater
moderate and the growth not adversely affected,
amount of 2,4DANT than 2,6DANT in the hydrol-
more 4ADNT than 2ADNT was recovered. The
ysates of the plants grown in contaminated water
soil in these pots contained TNT and its transfor-
compared to the plants grown in contaminated
mation products (Table 1). The plants grown in
soils. The 2,4DANT isomer can come from a sec-
the contaminated soil were stunted and no TNT
ondary reduction of either 2ADNT or 4ADNT;
transformation products were detected in the
2,6DANT, however, can come only from 2ADNT.
soil. In these plants, more 2ADNT than 4ADNT
The results of the in-situ humification and
was recovered. This difference may reflect a lack
leaching experiments are listed in Figure 2 and
of microbial activity in the highly contaminated
Table 2. The mass balance calculations are
soil as opposed to some active microbial activity
approximations based on single sacrificed plants
in the soils that received only moderate amounts
from one set of pots and leachates from a replicated
of explosives in small increments at each irrigation
set of pots. When the soil environment was cycled
event. Hughes et al. (1997), in experiments with
between anaerobic and aerobic, all of the TNT
hairy-root cultures grown in the presence of TNT,
and nearly all of its aminoDNT transformation
also found that the quantity of 4ADNT exceeded
2ADNT in cultures grown with associated rhizo-
products eventually became undetectable follow-
5
Previous Page
