title: Effect of humic deposit (leonardite) on degradation of semi-volatile and heavy hydrocarbons and soil quality in crude-oil-contaminated soil.
abstract: In order to investigate the bioremedial potential of humic deposit (leonardite), the effects of the treatments of leonardite and a commercial bioaugmentation agent on the degradation of a variety of petroleum hydrocarbons (C13-C31) and soil enzyme activities (urease acid-alkaline phosphatase and dehydrogenase) were tested within a soil incubation experiment lasting 120 days. Experimentally crude-oil-contaminated soil (2.5%) was regulated to a C:N:P ratio (100:15:1; Oilcon), amended with 5% of leonardite and regulated to the same C:N:P ratio (Oilcon-L) or mixed with a commercial bioaugmentation product (Oilcon-B), respectively. In the short period of incubation (60 days), Oilcon and Oilcon-B treatments showed higher hydrocarbon degradations, whereas Oilcon-L showed higher hydrocarbon degradation over Oilcon and Oilcon-B treatments in the long-term (120 days). Applying contaminated soil with leonardite increased urease (LSD, 4.978, *P<0.05) and dehydrogenase (LSD, 0.660, *P<0.05) activities. However, acid and alkaline phosphatase activities showed no certain inclination between different treatments. Dehydrogenase seemed to be more related to hydrocarbon degradation process. Overall results showed that leonardite enhanced biodegradation of petroleum hydrocarbons and also stimulated soil ecological quality measured as soil enzyme activities.
authors.affiliation: Department of Soil Science, Agriculture Faculty of Ankara University, Ankara, Turkey. turgay@agri.ankara.edu.tr
authors.forename: Oguz Can
authors.initials: OC
authors.lastname: Turgay
authors.forename: Esin Eraydın
authors.initials: EE
authors.lastname: Erdogan
authors.forename: Ayten
authors.initials: A
authors.lastname: Karaca
mesh_terms: D001673:Biodegradation, Environmental; D052918:Environmental Restoration and Remediation / Q000379:methods*; D004798:Enzymes / Q000032:analysis; D006812:Humic Substances; D006838:Hydrocarbons / Q000737:chemistry* / Q000378:metabolism; D008903:Minerals / Q000737:chemistry; D010578:Petroleum / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000737:chemistry / Q000378:metabolism
chemical_list: D004798:Enzymes; D006812:Humic Substances; D006838:Hydrocarbons; D008903:Minerals; D010578:Petroleum; D012987:Soil; D012989:Soil Pollutants; D055549:Volatile Organic Compounds