Application of Stable Isotope Enrichment

This has attracted considerable attention in evaluating the effectiveness of remediation either by natural populations or those enriched by specific additions. Isotopic analysis of the contaminant supplemented with that of established metabolites makes it possible to determine whether degradation 

Valnes of have been measnred for a number of polychlorinated biphenyl (PCB) congeners and applied to a nnmber of commercial PCB mixtures. Both the number and the position of the chlorine snbstitnents affected the depletion of C, and this reflected the mannfacturing procednres that involved kinetic isotope effects as well as the source of the biphenyl starting material (Jarman et al. 1998). It was snggested that this could be applied to determine the source of PCBs in the environment. 

An anaerobic bacterial enrichment cnltnre was used to examine the dechlorination of 2,3,4,5-tetrachlorobiphenyl that prodnced 2,3,5-trichlorobiphenyl exclusively. Although there was no alteration in the valnes of 5 C, compound-specific analysis of Arochlor 1268 showed that there was a trend for decreasing C abundance with increasing content of chlorine. This is consistent with dechlorination of the congeners with more chlorine substituents. 

It was snggested that rednctive dechlorination of PCBs wonld produce congeners with more depleted valnes of compared with unweathered Arochlors (Drenzer et al. 2001). 

Valnes of were measnred for the degradation of trichlorobenzenes (Griebler et al. 

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