Enhanced dissipation of phenanthrene in spiked soil by arbuscular mycorrhizal alfalfa combined with a non-ionic surfactant amendment

Experiments were conducted to assess the role of colonization of alfalfa roots by an arbuscular mycorrhizal (AM) fungus (Glomus etunicatum) in conjunction with a non-ionic surfactant (Triton X-100) in dissipation of phenanthrene in a soil spiked with phenanthrene at 0, 2.5, 5.0 and 10.0 mg kg− 1. After plant harvest the residual phenanthrene concentration in the soil decreased markedly. Mycorrhizal treatment enhanced phenanthrene dissipation in the rhizosphere and bulk soils irrespective of phenanthrene application rate. Addition of Triton X-100 resulted in the highest phenanthrene concentration in the rhizosphere soil among the treatments, while the lowest phenanthrene concentration in the bulk soil was obtained by AM inoculation and amendment with Triton X-100. AM inoculation and addition of the surfactant consistently promoted phenanthrene dissipation in the soil and decreased the microbial biomass based on phospholipid fatty acid (PLFA) analysis. PLFA profiles demonstrated that AM inoculation together with addition of Triton X-100 altered the microbial community structure in the rhizosphere soil. The results of this study provide a reference value for phytoremediation of soil contaminated by organic pollutants.