Sammendrag
We collected urban soil samples impacted by polycyclic
aromatic hydrocarbons (PAHs) from a sorbent-based remediation field
trial to address concerns about unwanted side-effects of 2% powdered
(PAC) or granular (GAC) activated carbon amendment on soil
microbiology and pollutant biodegradation. After three years, total
microbial cell counts and respiration rates were highest in the GAC
amended soil. The predominant bacterial community structure derived
from denaturing gradient gel electrophoresis (DGGE) shifted more
strongly with time than in response to AC amendment. DGGE band
sequencing revealed the presence of taxa with closest affiliations either
to known PAH degraders, e.g. Rhodococcus jostii RHA-1, or taxa known
to harbor PAH degraders, e.g. Rhodococcus erythropolis, in all soils.
Quantification by real-time polymerase chain reaction yielded similar
dioxygenases gene copy numbers in unamended, PAC-, or GACamended
soil. PAH availability assessments in batch tests showed the
greatest difference of 75% with and without biocide addition for
unamended soil, while the lowest PAH availability overall was
measured in PAC-amended, live soil. We conclude that AC had no detrimental effects on soil microbiology, AC-amended
soils retained the potential to biodegrade PAHs, but the removal of available pollutants by biodegradation was most notable in
unamended soil.
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