title: Native Michigan plants stimulate soil microbial species changes and PAH remediation at a legacy steel mill.
abstract: A 1.3-acre phytoremediation site was constructed to mitigate polyaromatic hydrocarbon (PAH) contamination from a former steel mill in Michigan. Soil was amended with 10% (v/v) compost and 5% (v/v) poultry litter. The site was divided into twelve 11.89 m X 27.13 m plots, planted with approximately 35,000 native Michigan perennials, and soils sampled for three seasons. Soil microbial density generally increased in subplots of Eupatorium perfoliatum (boneset), Aster novae-angliae (New England aster), Andropogon gerardii (big bluestem), and Scirpus atrovirens (green bulrush) versus unplanted subplots. Using enumeration assays with root exudates, PAH degrading bacteria were greatest in soils beneath plants. Initially predominant, Arthrobacter were found capable of degrading a PAH cocktail in vitro, especially upon the addition of root exudate. Growth of some Arthrobacter isolates was stimulated by root exudate. The frequency of Arthrobacter declined in planted subplots with a concurrent increase in other species, including secondary PAH degraders Bacillus and Nocardioides. In subplots supporting only weeds, an increase in Pseudomonas density and little PAH removal were observed. This study supports the notion that a dynamic interplay between the soil, bacteria, and native plant root secretions likely contributes to in situ PAH phytoremediation.
authors.affiliation: Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI 48128-1491, USA. jcthomas@umd.umich.edu
authors.forename: John C
authors.initials: JC
authors.lastname: Thomas
authors.forename: Edward
authors.initials: E
authors.lastname: Cable
authors.forename: Robert T
authors.initials: RT
authors.lastname: Dabkowski
authors.forename: Stephanie
authors.initials: S
authors.lastname: Gargala
authors.forename: Daniel
authors.initials: D
authors.lastname: McCall
authors.forename: Garett
authors.initials: G
authors.lastname: Pangrazzi
authors.forename: Adam
authors.initials: A
authors.lastname: Pierson
authors.forename: Mark
authors.initials: M
authors.lastname: Ripper
authors.forename: Donald K
authors.initials: DK
authors.lastname: Russell
authors.forename: Clayton L
authors.initials: CL
authors.lastname: Rugh
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D008669:Metallurgy; D008824:Michigan; D056265:Microbial Interactions; D053147:Plant Exudates / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D010944:Plants / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D036226:Seedlings / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants; D013045:Species Specificity; D013232:Steel
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D053147:Plant Exudates; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D013232:Steel