Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.envpol.2016.01.013
Title (Primary) Biodegradation of vapor-phase toluene in unsaturated porous media: Column experiments
Author Khan, A.M.; Wick, L.Y.; Harms, H.; Thullner, M.
Source Titel Environmental Pollution
Year 2016
Department UMB
Volume 211
Page From 325
Page To 331
Language englisch
Keywords Toluene; VOC; Biodegradation; Gas phase; Vertical flow filters; Isotopically labeled compound
UFZ wide themes RU3;
Abstract Biodegradation of organic chemicals in the vapor phase of soils and vertical flow filters has gained attention as promising approach to clean up volatile organic compounds (VOC). The drivers of VOC biodegradation in unsaturated systems however still remain poorly understood. Here, we analyzed the processes controlling aerobic VOC biodegradation in a laboratory setup mimicking the unsaturated zone above a shallow aquifer. The setup allowed for diffusive vapor-phase transport and biodegradation of three VOC: non-deuterated and deuterated toluene as two compounds of highly differing biodegradability but (nearly) identical physical and chemical properties, and MTBE as (at the applied experimental conditions) non-biodegradable tracer and internal control. Our results showed for toluene an effective microbial degradation within centimeter VOC transport distances despite high gas-phase diffusivity. Degradation rates were controlled by the reactivity of the compounds while oxic conditions were found everywhere in the system. This confirms hypotheses that vadose zone biodegradation rates can be extremely high and are able to prevent the outgassing of VOC to the atmosphere within a centimeter range if compound properties and site conditions allow for sufficiently high degradation rates.
Persistent UFZ Identifier
Khan, A.M., Wick, L.Y., Harms, H., Thullner, M. (2016):
Biodegradation of vapor-phase toluene in unsaturated porous media: Column experiments
Environ. Pollut. 211 , 325 - 331 10.1016/j.envpol.2016.01.013