title: Recalcitrance of polycyclic aromatic hydrocarbons in soil contributes to background pollution.
abstract: The microbial accessibility of native phenanthrene and pyrene was determined in soils representing background scenarios for pollution by polycyclic aromatic hydrocarbons (PAHs). The soils were selected to cover a wide range of concentrations of organic matter (1.7-10.0%) and total PAHs (85-952 μg/kg). The experiments included radiorespirometry determinations of biodegradation with (14)C-labeled phenanthrene and pyrene and chemical analyses to determine the residual concentrations of the native compounds. Part of the tests relied on the spontaneous biodegradation of the chemicals by native microorganisms; another part also involved inoculation with PAH-degrading bacteria. The results showed the recalcitrance of PAHs already present in the soils. Even after extensive mineralization of the added (14)C-PAHs, the concentrations of native phenanthrene and pyrene did not significantly decrease. We suggest that aging processes operating at background concentrations may contribute to recalcitrance and, therefore, to ubiquitous pollution by PAHs in soils.
authors.affiliation: Instituto de Recursos Naturales y Agrobiología de Sevilla, CSIC, Apartado 1052, E-41080 Seville, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Posada-Baquero
authors.forename: José-Julio
authors.initials: JJ
authors.lastname: Ortega-Calvo
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D004787:Environmental Pollution; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000378:metabolism; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism; D013997:Time Factors
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants