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Desorption and bioavailability of polycyclic aromatic hydrocarbons in contaminated soil subjected to long‐term in situ biostimulation
Author(s) -
Richardson Stephen D.,
Aitken Michael D.
Publication year - 2011
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.682
Subject(s) - biostimulation , environmental chemistry , chemistry , bioavailability , desorption , soil contamination , contamination , environmental remediation , in situ , soil water , bioremediation , soil science , environmental science , adsorption , organic chemistry , ecology , bioinformatics , biology
The distribution and potential bioavailability of polycyclic aromatic hydrocarbons (PAHs) in soil from a former manufactured‐gas plant (MGP) site were examined before and after long‐term biostimulation under simulated in situ conditions. Treated soil was collected from the oxygenated zones of two continuous‐flow columns, one subjected to biostimulation and the other serving as a control, and separated into low‐ and high‐density fractions. In the original soil, over 50% of the total PAH mass was associated with lower density particles, which made up <2% of the total soil mass. However, desorbable fractions of PAHs were much lower in the low‐density material than in the high‐density material. After more than 500 d of biostimulation, significant removal of total PAHs occurred in both the high‐ and low‐density materials (77 and 53%, respectively), with three‐ and four‐ring PAHs accounting for the majority of the observed mass loss. Total PAHs that desorbed over a 28‐d period were substantially lower in treated soil from the biostimulated column than in the original soil for both the high‐density material (23 vs. 63%) and the low‐density material (5 vs. 20%). The fast‐desorbing fractions quantified by a two‐site desorption model ranged from 0.1 to 0.5 for most PAHs in the original soil but were essentially zero in the biostimulated soil. The fast‐desorbing fractions in the original soil underestimated the extent of PAH biodegradation observed in the biostimulated column and thus was not a good predictor of PAH bioavailability after long‐term, simulated in situ biostimulation. Environ. Toxicol. Chem. 2011;30:2674–2681. © 2011 SETAC