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Environ Sci Technol

Title:		Predominance of biotic over abiotic formation of halogenated hydrocarbons in hypersaline sediments in Western Australia
Author(s):		Ruecker A; Weigold P; Behrens S; Jochmann M; Laaks J; Kappler A;
Address:		"Geomicrobiology, Center for Applied Geosciences, University of Tubingen , Tubingen 72074, Germany"
Journal Title:		Environ Sci Technol
Year:		2014
Volume:		20140730
Issue:		16
Page Number:		9170 - 9178
DOI:		10.1021/es501810g
ISSN/ISBN:		1520-5851 (Electronic) 0013-936X (Linking)
Abstract:		"Volatile halogenated organic compounds (VOX) contribute to ozone depletion and global warming. There is evidence of natural VOX formation in many environments ranging from forest soils to salt lakes. Laboratory studies have suggested that VOX formation can be chemically stimulated by reactive Fe species while field studies have provided evidence for direct biological (enzymatic) VOX formation. However, the relative contribution of abiotic and biotic processes to global VOX budgets is still unclear. The goals of this study were to quantify VOX release from sediments from a hypersaline lake in Western Australia (Lake Strawbridge) and to distinguish between the relative contributions of biotic and abiotic VOX formation in microbially active and sterilized microcosms. Our experiments demonstrated that the release of organochlorines from Lake Strawbridge sediments was mainly biotic. Among the organochlorines detected were monochlorinated, e.g., chloromethane (CH3Cl), and higher chlorinated VOX compounds such as trichloromethane (CHCl3). Amendment of sediments with either Fe(III) oxyhydroxide (ferrihydrite) or a mixture of lactate/acetate or both ferrihydrite and lactate/acetate did not stimulate VOX formation. This suggests that although microbial Fe(III) reduction took place, there was no stimulation of VOX formation via Fe redox transformations or the formation of reactive Fe species under our experimental conditions"
Keywords:		"Acetates/pharmacology *Air Pollutants/chemistry/metabolism Ferric Compounds/pharmacology Geologic Sediments/chemistry/microbiology *Hydrocarbons, Chlorinated/chemistry/metabolism Lactic Acid/pharmacology Lakes Oxidation-Reduction Salinity Western Australi;"
Notes:		"MedlineRuecker, A Weigold, P Behrens, S Jochmann, M Laaks, J Kappler, A eng Research Support, Non-U.S. Gov't 2014/07/31 Environ Sci Technol. 2014 Aug 19; 48(16):9170-8. doi: 10.1021/es501810g. Epub 2014 Jul 30"