title: Assessing impediments to hydrocarbon biodegradation in weathered contaminated soils.
abstract: In this study, impediments to hydrocarbon biodegradation in contaminated soils were assessed using chemical and molecular methodologies. Two long-term hydrocarbon contaminated soils were utilised which were similar in physico-chemical properties but differed in the extent of hydrocarbon (C10-C40) contamination (S1: 16.5 g kg(-1); S2: 68.9 g kg(-1)). Under enhanced natural attenuation (ENA) conditions, hydrocarbon biodegradation was observed in S1 microcosms (26.4% reduction in C10-C40 hydrocarbons), however, ENA was unable to stimulate degradation in S2. Although eubacterial communities (PCR-DGGE analysis) were similar for both soils, the alkB bacterial community was less diverse in S2 presumably due to impacts associated with elevated hydrocarbons. When hydrocarbon bioaccessibility was assessed using HP-β-CD extraction, large residual concentrations remained in the soil following the extraction procedure. However, when linear regression models were used to predict the endpoints of hydrocarbon degradation, there was no significant difference (P>0.05) between HP-β-CD predicted and microcosm measured biodegradation endpoints. This data suggested that the lack of hydrocarbon degradation in S2 resulted primarily from limited hydrocarbon bioavailability.
authors: School of Biological Sciences, Flinders University, Adelaide, South Australia, 5001, Australia.
authors: Eric
authors: E
authors: Adetutu
authors: John
authors: J
authors: Weber
authors: Sam
authors: S
authors: Aleer
authors: Catherine E
authors: CE
authors: Dandie
authors: Arturo
authors: A
authors: Aburto-Medina
authors: Andrew S
authors: AS
authors: Ball
authors: Albert L
authors: AL
authors: Juhasz
mesh_terms: D001673:Biodegradation, Environmental; D001682:Biological Availability; D042926:Cytochrome P-450 CYP4A / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics; D005798:Genes, Bacterial; D006838:Hydrocarbons / Q000378:metabolism*; D012240:Rhodococcus / Q000235:genetics* / Q000378:metabolism; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D004275:DNA, Ribosomal; D006838:Hydrocarbons; D012989:Soil Pollutants; D042926:Cytochrome P-450 CYP4A
keywords: AlkB; Bioavailability; Biodegradation; Bioremediation; Hydrocarbons