The concentrations of PAHs in aged PAH-contaminated soils
during biodegradation were presented in Fig. 1. The initial PAH
concentration (8.33mg kg−1) in sterile soil was higher than that in
non-sterile soil (8.15mgkg−1) in this study. In contrast, the study
of Mueller and Shann [22] found that there were no significant
differences in total PAH concentration before and after sterilization
in soil. After inoculation, PAHs were rapidly degraded from
soils of three treatments in the first 8 d, in which period 25–30%
of PAHs were biodegraded for all treatments, then followed by a
slower decreasing. No significant difference existed between BM
and BMN soils, in both of soils only 41.3% and 40.7% of PAHs were
biodegraded, respectively (P < 0.05), at 64 d after inoculation. The
PAH concentration in BNN soil was significantly higher than that in
other two treatments at 64 d after inoculation (P < 0.05). Notably,
the degradation of PAHs in BMN soil was not significant as compared
to BM and BNN soils from 0 to 4 d. There was a significant
increase for PAH concentrations in BM soil compared to BMN and
BNN from 8 to 16 d (P < 0.05).