title: Insights into the biodegradation of weathered hydrocarbons in contaminated soils by bioaugmentation and nutrient stimulation.
abstract: The potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation.
authors.affiliation: School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK.
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK.
authors.forename: Kirsty J
authors.initials: KJ
authors.lastname: Brassington
authors.affiliation: School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK.
authors.forename: George
authors.initials: G
authors.lastname: Prpich
authors.affiliation: Institute of Biological and Environmental Sciences, Cruickshank Building, University of Aberdeen, Aberdeen, Scotland, AB24 3UU, UK.
authors.forename: Graeme I
authors.initials: GI
authors.lastname: Paton
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
authors.forename: Kirk T
authors.initials: KT
authors.lastname: Semple
authors.affiliation: School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK.
authors.forename: Simon J T
authors.initials: SJT
authors.lastname: Pollard
authors.affiliation: School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK. Electronic address: f.coulon@cranfield.ac.uk.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Coulon
mesh_terms: D000641:Ammonia / Q000032:analysis; D001673:Biodegradation, Environmental; D054750:Ecotoxicology; D006838:Hydrocarbons / Q000032:analysis* / Q000378:metabolism; D059013:Microbial Consortia / Q000187:drug effects; D009566:Nitrates / Q000032:analysis; D010578:Petroleum / Q000032:analysis* / Q000378:metabolism; D059392:Petroleum Pollution / Q000032:analysis*; D010710:Phosphates / Q000032:analysis; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D014887:Weather
chemical_list: D006838:Hydrocarbons; D009566:Nitrates; D010578:Petroleum; D010710:Phosphates; D012987:Soil; D012989:Soil Pollutants; D000641:Ammonia
keywords: Bioaugmentation; Bioremediation; Biostimulation; Soil contamination; Weathered petroleum hydrocarbon