title: Soil biotransformation of thiodiglycol, the hydrolysis product of mustard gas: understanding the factors governing remediation of mustard gas contaminated soil.
abstract: Thiodiglycol (TDG) is both the precursor for chemical synthesis of mustard gas and the product of mustard gas hydrolysis. TDG can also react with intermediates of mustard gas degradation to form more toxic and/or persistent aggregates, or reverse the pathway of mustard gas degradation. The persistence of TDG have been observed in soils and in the groundwater at sites contaminated by mustard gas 60 years ago. The biotransformation of TDG has been demonstrated in three soils not previously exposed to the chemical. TDG biotransformation occurred via the oxidative pathway with an optimum rate at pH 8.25. In contrast with bacteria isolated from historically contaminated soil, which could degrade TDG individually, a consortium of three bacterial strains isolated from the soil never contaminated by mustard gas was able to grow on TDG in minimal medium and in hydrolysate derived from an historical mustard gas bomb. Exposure to TDG had little impacts on the soil microbial physiology or on community structure. Therefore, the persistency of TDG in soils historically contaminated by mustard gas might be attributed to the toxicity of mustard gas to microorganisms and the impact to soil chemistry during the hydrolysis. TDG biodegradation may form part of a remediation strategy for mustard gas contaminated sites, and may be enhanced by pH adjustment and aeration.
authors: Natural Environmental Research Council, Centre for Ecology and Hydrology, Mansfield Road, Oxford, OX1 3SR, UK. lihong@ceh.ac.uk
authors: Hong
authors: H
authors: Li
authors: Robert
authors: R
authors: Muir
authors: Neil R
authors: NR
authors: McFarlane
authors: Richard J
authors: RJ
authors: Soilleux
authors: Xiaohong
authors: X
authors: Yu
authors: Ian P
authors: IP
authors: Thompson
authors: Simon A
authors: SA
authors: Jackman
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001711:Biotransformation; D002619:Chemical Warfare Agents / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009151:Mustard Gas / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002619:Chemical Warfare Agents; D012989:Soil Pollutants; D013438:Sulfhydryl Compounds; C047519:2,2'-thiodiethanol; D009151:Mustard Gas