Fluorescence Excitation-Emission Matrix Characteristics and Implication of Dissolved Organic Matter in Groundwater at a Typical Refinery-Polluted Site

The excitation-emission matrix (EEMs) fluorescence spectroscopy of dissolved organic matter (DOM) has been widely used in monitoring and warning of water pollution. To clarify the indicator of EEMs fluorescence fingerprint on groundwater organic pollution at refinery sites, the EEMs characteristics of DOM and spatial distribution of organic pollution in groundwater was studied at a typical refinery-polluted site by EEMs regional integration, correlation analysis and hierarchical clustering. The EEMs results show that DOM in groundwater of the polluted site had significant fluorescence spectral fingerprint as oil contaminants. The constituents of DOM in the polluted groundwater were quantified by EMMs regional integration based on fluorescence of model compounds. The normalized volumetric integration of regions Ⅰ and Ⅱ representing benzene series and petroleum hydrocarbons accounts for 55%-88% of the total volumetric integration of all regions, which is consistent with GC-MS results of organic compositions. The hierarchical clustering on the similarity of EEMs can effectively distinguish the types of groundwater organic pollution and their spatial distribution in the polluted site. The correlation analyses between normalized volumetric integration of EEMs regions and organic components, spectra parameters and water chemistry further suggest that the fluorescence EEMs fingerprint of DOM can effectively reveal organic pollution and effect on geochemistry of groundwater at the refinery site, indicating as an effective tracer to monitor and warn groundwater organic pollution.