title: Reactive iron barriers: a niche enabling microbial dehalorespiration of 1,2-dichloroethane.
abstract: A reactive iron barrier in a contaminated aquifer with low pH was found to dechlorinate 1,2-dichloroethane (1,2-DCA) in situ. This chlorinated ethane is known to resist abiotic reduction by zero valent iron. Samples taken up-gradient and within the barrier were used to inoculate anaerobic batch cultures amended with various electron donors. Cultures inoculated with groundwater from within the reactive iron barrier reduced 1,2-DCA to ethene. The same effect could be achieved by simultaneously supplying hydrogen while neutralising pH. The presence of iron or hydrogen at neutral pH had negligible effects on 1,2-DCA reduction in cultures inoculated with groundwater sampled up-gradient of the barrier. Molecular microbial community characterisation revealed that Dehalobacter species were more abundant in groundwater sampled from within the barrier. These findings suggest reactive iron barriers represent a remediation technology for 1,2-DCA degradation acting through in situ recruitment of 1,2-DCA reducing bacteria such as Dehalobacter.
authors.affiliation: Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Olivier
authors.initials: O
authors.lastname: Zemb
authors.forename: Matthew
authors.initials: M
authors.lastname: Lee
authors.forename: Adrian
authors.initials: A
authors.lastname: Low
authors.forename: Mike
authors.initials: M
authors.lastname: Manefield
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D044822:Biodiversity; D002713:Chlorine / Q000378:metabolism; D005025:Ethylene Dichlorides / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism*; D014871:Water Microbiology
chemical_list: D005025:Ethylene Dichlorides; D005030:Ethylenes; D002713:Chlorine; C024565:ethylene dichloride; D006859:Hydrogen; C036216:ethylene; D007501:Iron