TY - JOUR

T1 - Temporal changes in the extractability, bioaccessibility and biodegradation of target hydrocarbons in soils from former refinery facilities

AU - Towell, Marcie

AU - Vazquez Cuevas, Gabriela

AU - Bellarby, Jessica

AU - Paton, Graeme I.

AU - Coulon, Frederic

AU - Pollard, Simon J. T.

AU - Semple, Kirk

N1 - This is the author’s version of a work that was accepted for publication in International Biodeterioration & Biodegradation. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Biodeterioration & Biodegradation, 160, 2021 DOI: 10.1016/j.ibiod.2021.105227

PY - 2021/5/31

Y1 - 2021/5/31

N2 - This study investigated the extractability, bioaccessibility and biodegradation of 14C-phenanthrene and 14C-octacosane in two soils from former oil refinery facilities over 341 days. The impact of biostimulation and bioaugmentation treatments was also evaluated. At 0, 31, 62, 124 and 341 days, the loss and extractability (using dichloromethane, methanol:water and hydroxypropyl-β-cyclodextrin (HPCD)) of the 14C-hydrocarbons were measured. Further at each time point, the mineralisation of the 14C-hydrocarbons was measured respirometrically under the different conditions. In general, extractions with methanol: water and HPCD were similar for both hydrocarbons in the different treatments; however, these values were less that those measured with DCM. Overall, significantly higher (p ≤ 0.05) amounts of 14C-phenanthrene were lost, readily extracted and mineralised in the soils, with treatments having little impact upon the degradation of this hydrocarbon over 341 days. Conversely, bioaugmentation significantly increased the loss of 14C-octacosane residues from soils and sustained degradation after 31 days. Surprisingly, HPCD and methanol:water both under-predicted the extent to which the contaminants were degraded at each time point. Determining the likelihood of effective biodegradation by the stimulation of indigenous microorganisms or through bioaugmentation needs to be assessed by both chemical and biological measurements of bioaccessibility, rather than just by that which is totally extractable from soil. However, soils which have high loadings of organic matter and/or organic contaminants may prevent accurate assessment of contaminant bioaccessibility, as measured by HPCD.

AB - This study investigated the extractability, bioaccessibility and biodegradation of 14C-phenanthrene and 14C-octacosane in two soils from former oil refinery facilities over 341 days. The impact of biostimulation and bioaugmentation treatments was also evaluated. At 0, 31, 62, 124 and 341 days, the loss and extractability (using dichloromethane, methanol:water and hydroxypropyl-β-cyclodextrin (HPCD)) of the 14C-hydrocarbons were measured. Further at each time point, the mineralisation of the 14C-hydrocarbons was measured respirometrically under the different conditions. In general, extractions with methanol: water and HPCD were similar for both hydrocarbons in the different treatments; however, these values were less that those measured with DCM. Overall, significantly higher (p ≤ 0.05) amounts of 14C-phenanthrene were lost, readily extracted and mineralised in the soils, with treatments having little impact upon the degradation of this hydrocarbon over 341 days. Conversely, bioaugmentation significantly increased the loss of 14C-octacosane residues from soils and sustained degradation after 31 days. Surprisingly, HPCD and methanol:water both under-predicted the extent to which the contaminants were degraded at each time point. Determining the likelihood of effective biodegradation by the stimulation of indigenous microorganisms or through bioaugmentation needs to be assessed by both chemical and biological measurements of bioaccessibility, rather than just by that which is totally extractable from soil. However, soils which have high loadings of organic matter and/or organic contaminants may prevent accurate assessment of contaminant bioaccessibility, as measured by HPCD.

KW - Phenanthrene

KW - Octacosane

KW - Bioaccessibility

KW - Mineralisation

KW - Bioaugmentation

KW - Biostimulation

U2 - 10.1016/j.ibiod.2021.105227

DO - 10.1016/j.ibiod.2021.105227

M3 - Journal article

VL - 160

JO - International Biodeterioration and Biodegradation

JF - International Biodeterioration and Biodegradation

SN - 0964-8305

M1 - 105227

ER -