Stable Isotopes for the Characterisation of NOM and Investigation of the Different Organic Precursors of Aquatic Systems

This project aims to develop and test the utility of stable isotopic analysis for characterising and establishing the main precursors of dissolved organic carbon (DOC). Stable isotopic data of NOM will be obtained on both a whole sample and a compound specific basis to investigate the utility of stable isotope analysis for studying the source input, temporal and spatial dynamics (e.g., bioproductivity), transportation and fate of organic material in source water systems. A range of NOM samples will be studied since the chemical and physical nature of NOM is dependent on the source materials and surrounding environmental conditions, hence NOM from different locations can vary considerably in structure and behaviour . NOM fractions will be separately studied to establish the relationship between the structural moieties of NOM and specific organic precursors. A correlation of the source inputs of organics in the source waters with the subsequent occurrence of certain DBPs following treatment may also help identify which precursors are most significant with respect to DBP formation. For isotope analyses c omplex organics such as NOM often need to be separated into simplistic fractions prior to analysis. This can be achieved by chemical degradation (e.g. CuO) or off-line pyrolysis followed by column chromatography to produce less complex fractions on the basis of solubility in solvents of different polarity. New chemical and enzymatic degradation techniques, which selectively target specific structural bonds (e.g., C-N, C-O, C-S bonds), will be developed to produce relatively clean fractions suitable for compound specific isotope analysis (CSIA).

Personnel

K. Grice, P.F. Greenwood, R. Kagi, R. Trolio, D. White

Funding

CRC-WQT

Collaborators

University of Western Australia, Water Corporation (WA)