Environmental Engineering Reference
In-Depth Information
Table 7.13
Decrease in Total PAH, Individual Homologues, and Total BaP Toxic
Equivalent Compounds in POPILE Soil After 11 Months of Treatment in Microcosms
Bulking Agent +
Dried-Blood
Fertilizer
+
P. aeruginosa
Strain 64
Bulking Agent +
Dried-Blood
Fertilizer
No. Treatment
(
1
/
2
)
PA H
%
Decrease
a
%
Decrease
a
%
Decrease
a
mg/kg
mg/kg
mg/kg
b
Acenapthene
201.0
c
26.3
157.5
c
42.2
0
100.0
Fluorene
352.1
c
9.9
251.7
35.6
18.2
95.3
Phenanthrene
1339.8
c
37.1
1052.3
50.6
42.7
98.0
Anthracene
705.5
c
17.3
739.7
c
13.2
178.4
79.0
Fluoranthene
779.0
c
20.4
652.8
c
33.3
43.9
95.5
Pyrene
612.3
c
0.2
517.8
c
19.8
286.7
55.6
Benz(a)anthracene
148.0
c
16.8
120.2
32.5
36.5
79.5
Chrysene
168.5
c
7.7
153.5
c
15.9
31.0
83.0
Benzo(b)fluoranthene
65.4
c
0.0
61.0
c
0.0
52.2
0.0
Benzo(k)fluoranthene
57.2
c
0.0
57.2
c
0.0
51.8
c
0.0
Benzo(a)pyrene
48.4
c
0.0
39.8
c
1.0
35.6
11.3
Total PAH
4477.3
22.6
3803.7
34.3
777.2
86.6
Total BaP equivalents
70.5
48.4
58.7
57.1
45.1
67.1
a
Averages with different superscripts are significantly different by two tailed student t-test
(p < 0.05).
b
Average of two microcosms.
c
Controls and the biostimulation treatment were the averages of three microcosms.
decrease in total PAHs and a 59% decrease in total BaP equivalents. The
bioaugmented microcosm showed an 87% decrease in total PAHs and a 67%
decrease in total BaP equivalents.
The concentrations of several PAHs in the amended soil inoculated with
P. aeruginosa
strain 64 declined significantly over the 11-month treatment
period. Although various pseudomonads have been reported capable of
catabolizing some low-molecular-weight PAHs,
P. aeruginosa
strain 64 did
not degrade phenanthrene or HMW PAHs. Therefore, the enhancement of
PAH degradation after the addition of this microorganism suggests that the
autochthonous degrading community contains some cometabolic activity
that was stimulated by the biosurfactant-producing
P. aeruginosa
strain 64.
One of the triplicates in this treatment failed to show significant degradation
of the higher-molecular-weight PAHs, presumably due to the failure of the
autochthonous population in that microcosm to develop as it did in the other
microcosms.
The mechanism by which
P. aeruginosa
strain 64 is able to stimulate the
autochthonous degrading community is not clear. Notable changes in the
soil occurred in the bioaugmented microcosms that were not observed in
the control (no amendment) or the biostimulation treatments. After a period
of 3 to 4 weeks, the color of the PAH-contaminated soil was much darker in
