Microbial Transformations of Substituted Benzenes during Infiltration of River Water to Groundwater: Laboratory Column Studies

Abstract

The microbial transformations of dimethyl- and di-chlorobenzenes have been studied in laboratory aquifer columns simulating saturated-flow conditions typical for a river water/groundwater infiltration system. The behavior of all compounds in the laboratory was qualitatively the same as that observed at a field site. Both dimethyl-and dichlorobenzenes were biotransformed under aerobic conditions, the dimethylbenzenes faster than the chlorinated analogues. Evidence is presented that dimethyl-benzenes are degraded by denitrifying bacteria under anaerobic conditions. Dichlorobenzenes were not transformed under these conditions. Significant differences in the rates of transformation between isomers were found. The dimethylbenzenes and p-dichlorobenzene appeared to be utilized by bacteria as sole carbon and energy sources. Transfer of rate constants determined in the laboratory at elevated substrate concentrations to the field was difficult. © 1985, American Chemical Society. All rights reserved.