| Abstract
| - In situ microcosms (ISM) and laboratory batchmicrocosms (LBM) were used for determination of thefirst-order degradation rate constants of benzene,toluene, o-xylene, nitrobenzene, naphthalene,biphenyl,o- and p-dichlorobenzene, 1,1,1-trichloroethane,tetrachloromethane, trichloroethene, tetrachloroethene,phenol, o-cresol, 2,4- and 2,6-dichlorophenol,4,6-o-dichlorocresol, and o- and p-nitrophenol in anaerobicaquifer. All aromatic hydrocarbons were degradedin ISM and LBM experiments. The phenolichydrocarbons were all degraded in ISM experiments,but some failed to degrade in LBM experiments.Chlorinated aliphatic hydrocarbons were degradedneither in ISM nor LBM experiments. Degradation rateconstants were determined by a model accountingfor kinetic sorption (bicontinuum model), lag phases,and first-order degradation. With a few exceptions,lag phases were less than 2 weeks in both ISM andLBM experiments. First-order degradation rateconstants for aromatic and phenolic hydrocarbonsranged between 0.01 and 0.9 day-1. Localvariationsin first-order degradation rates and variationsbetween rate constants determined by ISM and LBMwere generally within a factor of 5, but no systematicdifferences were observed between rate constantsdetermined in situ and in the laboratory.
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