Phenotypic responses of the soil bacterial community to polycyclic aromatic hydrocarbon contamination in soils

Five soils with different levels of polycyclic aromatic hydrocarbon (PAH) and metallic contamination were sampled from a former coke facility site located in the north of France. Among PAH-degrading microbiota, naphthalene-degraders were ubiquitous, whereas bacteria-degrading PAHs of more than two rings were present in only the polluted soils, in the range of 1% to 10% of the total microbiota. Phenotypic characterization of PAH-degraders has revealed that several genera of bacteria are well represented such as Corynebacterium, Arthrobacter, and Pseudomonas. The diversity of the cultivable PAH-degrading bacterial community was dependent on the type and pollution level of soil (texture and depth). An important toxicity was measured in the polluted soils in relation to the combined effects of organic and metallic pollutions.