AWWA JAW17286

In the study reported here, tetrachloromethane and 1,1,1-trichloroethane were transformed in microcosms composed of aquifer materials to trichloromethane and 1,1-dichoroethane respectively. Further observations of trichloroethene and tetrachlorethene in microcosms demonstrated the transformation of these compounds to dichloroethene. Biotransformation products of these four solvents by freshwater sediment microbiota, in sealed static microcosms, were determined by gas chromatography during incubation at ambient temperatures in the dark for periods of up to sixteen weeks. Under conditions of neutral to acid pH, reductive potential, and the absence of oxygen and light, reductive dehalogenation of these four compounds occurred. Chlorinated alkenes were consistently more resistant to biotransformation than the chlorinated alkanes. Includes 27 references, tables, figures.