title: Comparison of the effects of variable site temperatures and constant incubation temperatures on the biodegradation of petroleum hydrocarbons in pilot-scale experiments with field-aged contaminated soils from a cold regions site.
abstract: Temporal atmospheric temperature changes during summers at sub-Arctic sites often cause periodic fluctuations in shallow landfarm and surface soil temperatures. However, little information is available on the effect of site-relevant variations on biodegradation performance in cold climates. This study compares the rate and extents of biodegradation of petroleum hydrocarbons at variable site temperatures (1-10 °C) representative of summers at a sub-Arctic site reported previously with those obtained under a constant average temperature of 6 °C. The biodegradation was evaluated in pilot-scale landfarming experiments with field-aged petroleum-contaminated soils shipped from Resolution Island (61°30'N, 65°00'W), Nunavut, Canada. Under the variable site temperature conditions biodegradation rate constants of semi- (F2) and non-volatile (F3) hydrocarbon fractions were enhanced by over a factor of two during the 60-d experiment, compared to the constant temperature mode. The decrease in total petroleum hydrocarbons (TPH) under the variable site temperature mode was 55% compared to only 19% under the constant average temperature mode. The enhanced biodegradation is attributable to the non-linear acceleration of microbial activity between 4.7 and 10°C and faster growth of indigenous hydrocarbon-degrading microbial populations. The first-order biodegradation rate constants of 0.018, 0.024 and 0.016 d(-1) for TPH, F2 and F3 fractions at the variable site temperature were in agreement with those determined by an on-site experiment at the same site.
authors.affiliation: Department of Civil Engineering, McGill University, Montreal, Canada.
authors.forename: Wonjae
authors.initials: W
authors.lastname: Chang
authors.forename: Lyle
authors.initials: L
authors.lastname: Whyte
authors.forename: Subhasis
authors.initials: S
authors.lastname: Ghoshal
mesh_terms: D001110:Arctic Regions; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D044822:Biodiversity; D003081:Cold Climate; D015169:Colony Count, Microbial; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D010578:Petroleum / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013696:Temperature
chemical_list: D006841:Hydrocarbons, Aromatic; D010578:Petroleum; D012989:Soil Pollutants