| Abstract
| - Compound-specific isotope analysis (CSIA) is an increasinglyimportant tool for the qualitative and quantitativeassessment of transformations of organic compounds incontaminated environments. To date, the use of CSIA hasbeen mainly restricted to the elements C and H, althoughN constitutes a very important reactive center for many prioritycontaminants. To evaluate the potential use of N isotopeeffects in the fate assessment of organic contaminants, weinvestigated the N isotope enrichment during the abioticreduction of 4 substituted nitroaromatic compounds (NACs),using two abiotic model reductants, namely Fe(II) sorbedto goethite (α-FeOOH) and juglone (8-hydroxy-1,4-naphthoquinone) in the presence of H2S. Substantial andvirtually identical isotope enrichment factors, εN, of about−30‰, indicative of the breaking of one N−O bond,were found for all NACs, regardless of the reductant involvedand the substitution of the NAC. These results indicatethat the εN-values determined in our study could berepresentative for the reduction of aromatic NO2-groupsand thus be used to assess the abiotic transformation ofNACs qualitatively and quantitatively in complex anoxicenvironments.
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