Biotransformations of selected alkylbenzenes and halogenated aliphatic hydrocarbons in methanogenic aquifer material: a microcosm study.

Leachates from municipal landfills commonly contain a variety of organic contaminants of industrial origin. The behavior of these compound in anaerobic, and particularly in methanogenic, subsurface materials is poorly understood. The behavior of benzene, toluene, ethylbenzene, o-xylene, 1,1-dichloroethylene, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene, trichloroethylene, and 1,2-dibromoethane was studied in authentic aquifer material known to support methanogenesis. These compounds are frequently found as contaminants in groundwater used for municipal water supplies. The disappearance of all compounds was observed with long lag times required before initiation of degradation of 1,1-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene, benzene, ethyl-benzene, and o-xylene. (/sup 14/C)Toluene degraded to CO/sub 2/. Vinyl chloride was found was a daughter product of 1,1-dichloroethylene, trans-1,2-dichloroethylene, and tri-chloroethylene. 1,2-Dichloroethylene was also observed as a degradation product of trichloroethylene. No daughter products were identified for the remaining compounds. 30 references, 3 tables.