title: Steam-treatment-based soil remediation promotes heat-tolerant, potentially pathogenic microbiota.
abstract: We investigated microbiota in surface and subsurface soil from a site, above steam-treated deep sub-soil originally contaminated with chlorinated solvents. During the steam treatment, the surface soil reached temperatures c. 30 degrees C higher than the temperature in untreated soil; whereas the subsurface soil, at a depth of about 40 cm, reached a temperature c. 45 degrees C higher than untreated soil. The soil was examined prior to, during, and 6, 12, 14, 20 and 31 months after treatment. Numbers of bacteria cultivable at 42 degrees C increased significantly in subsurface soil. Similarly, substrate utilization in ECOLOG plates, incubated at 42 degrees C, increased from less than 10% of available carbon sources in the untreated soil to more than 60% of the available carbon sources in the steam-treated soil. Aspergillus fumigatus was quantified as an example ofheat-tolerant fungi normally found in compost. These organisms are rarely detected in Danish soils but high numbers (c. 10(5) hyphal forming units g(-1)) occurred in the treated soil up to 31 months after the steam-treatment. We conclude that steam-treatment leads to changes of the microbial communities. Some changes are temporary while others can last for years after termination of the steam-treatment; reflecting different strategies that soil microorganisms follow.
authors.forename: Andreas
authors.initials: A
authors.lastname: Altenburger
authors.forename: Mikkel
authors.initials: M
authors.lastname: Bender
authors.forename: Flemming
authors.initials: F
authors.lastname: Ekelund
authors.forename: Susanne
authors.initials: S
authors.lastname: Elmholt
authors.forename: Carsten Suhr
authors.initials: CS
authors.lastname: Jacobsen
mesh_terms: D001232:Aspergillus fumigatus / Q000254:growth & development; D001419:Bacteria / Q000254:growth & development*; D001673:Biodegradation, Environmental; D002713:Chlorine / Q000737:chemistry*; D005658:Fungi / Q000254:growth & development*; D060587:Groundwater; D006358:Hot Temperature; D059013:Microbial Consortia; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013227:Steam; D013696:Temperature; D013997:Time Factors; D014873:Water Pollutants / Q000032:analysis
chemical_list: D012987:Soil; D012989:Soil Pollutants; D012997:Solvents; D013227:Steam; D014873:Water Pollutants; D002713:Chlorine