Segmented, Rhizon filtered sediment core interstitial pore water was characterized to elucidate natural biotic and abiotic attenuated remediation degradation pathways of 13C2 labeled halo-carbons (HCs) by 13C NMR. Measuring a site's in-situ capacity (soil/water) for transformation directly by treating it with a 13C labeled HCs substrate that is capable of undergoing the fundamental processes of oxidation, reduction, and substitution allows the chemistry that occurs to characterize the site. Both the nature and rates of these transformations can be assessed, 13C NMR and headspace gas chromatography/mass spectroscopy. The mechanistic HCs degradation pathway can be confounded by oxidation-reduction potential (ORP) of the environment and its pH, clarifying in-situ metal oxidation states and the potential microbial consortia activity. An increased degradation rate of HCs (F, Cl and Br) can be accomplished via prior iodination of the substrate or iodide in-situ treatment. The increased degradation rates are compared and contrasted between authentic iodated substrates and their halogenated equivalents substrates and in-situ treatments via 13C NMR. This work has important implications from both a climate perspective and for what it tells us about the HCs biogeochemical cycling and their release into the ecosystem.

13C NMR analysis of 13C2 molecules to model in-situ sediment halogenated organic carbons transformations

2019 Spring National Meeting

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