Biotransformation of trichloroethene in a variety of subsurface materials

Abstract The abilities of three types of sediment to biotransform trichloroethene (TCE) were compared to determine the influence of environmental factors that differ among sediments of different composition. The results could suggest TCE behavior at spill sites in a variety of subsurface materials. Microcosms containing water and sediment ranging from predominantly organic material to calcareous rock were spiked to contain 5 mg/L of TCE and allowed to incubate in the dark at 25°C. TCE was completely transformed to cis-1,2-dichloroethene (CIS) in one year by a sandy organic sediment that was contaminated with TCE prior to microcosm construction. Microcosms prepared with crushed rock and water, which contained low microbial biomass, depleted all the TCE spike in 21 months of incubation; however, less than 10% of the depleted TCE was recovered as 1,2-dichloroethene. Sodium acetate was added to selected microcosms for the purpose of increasing active microbial populations; however, this had no effect on the depletion of TCE.