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Direct Link between Fluoranthene Biodegradation and the Mobility and Sequestration of its Residues during Aging
Author(s) -
Vessigaud S.,
PerrinGanier C.,
Belkessam L.,
Denys S.,
Schiavon M.
Publication year - 2007
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2006.0473
Subject(s) - fluoranthene , environmental chemistry , biodegradation , chemistry , soil water , dichloromethane , microbial biodegradation , soil science , solvent , environmental science , organic chemistry , geology , phenanthrene , bacteria , microorganism , paleontology
The aim of this study was to assess the influence of the polycyclic aromatic hydrocarbons (PAH)‐degrading activity in the fate of fluoranthene in soils. Three soil samples with different degrading activities (an industrial soil, the same industrial soil after biostimulation, and an agricultural soil) were spiked with 14 C‐fluoranthene and incubated for 6 mo with monitoring of biodegradation and mineralization. To follow the distribution of the 14 C‐fluoranthene residues (i.e., 14 C‐fluoranthene and its degradation products) among the soil compartments, we performed successively leaching, centrifugation (to collect intra‐aggregate pore water), solvent extraction, and combustion of the soil columns. In the industrial soil, no mineralization of 14 C‐fluoranthene was observed, and only 3% of the initial 14 C‐activity was non‐extractable (with acetone:dichloromethane) after 165 d of incubation. The biostimulation (addition of unlabeled polycyclic aromatic hydrocarbons) increased the degrading activity in this soil (59% of 14 C‐fluoranthene was mineralized) and increased the residues sequestration (13% of 14 C‐activity was non‐extractable). The microflora of the agricultural soil mineralized 14 C‐fluoranthene more slowly and to a lesser extent (25%) than the biostimulated soil, but a higher amount of 14 C‐activity was sequestered (41%). Thus, the rate and extent of 14 C‐fluoranthene mineralization seemed to be related to the 14 C‐activity sequestration by controlling the accumulation of degradation products in the soil. 14 C‐Fluoranthene biodegradation enhanced the concentration of 14 C‐polar compounds in the intra‐aggregate pore water. Our results point out the close link between fluoranthene biodegradation and two key aging processes, diffusion and sequestration, in soils. Biodegradation controls the mobility and sequestration of residues by transforming fluoranthene into more polar molecules that can diffuse into the intra‐aggregate pore water and then might become bound to the matrix or entrapped in the microporosity.