Parallel factor analysis with three-dimensional excitation-emission matrix spectroscopy on dissolved organic matter of rural black and odorous water bodies in Pingdu City of Shandong Province

Three-dimensional excitation-emission matrix spectroscopy (EEMs) combined with parallel factor analysis (PARAFAC) were used to analyze the components, humification degree and sources of dissolved organic matter (DOM) of rural black and odorous water bodies in Pingdu City of Shandong Province. The results showed that the DOM of rural black and odorous water bodies in the city contained five categories and six fluorescence components, including tryptophan-like fluorescence components (C1 and C6), humus-like fluorescence components (C2), fluorescence components produced by plankton activities (C3), humic acid-like fluorescence components (C4), and fulic-like fluorescence components (C5). The water bodies with fluorescence index, autochthonous index, humification index and freshness index of 1.6-1.9, 0.8-1.0, 0.6-3.0 and 0.80-0.95, respectively, accounted for 90% of all, indicating that the DOM in rural black and odorous water bodies in the city had the dual characteristics of endogenous and exogenous, and had weak humification characteristics. The correlation analysis showed that the positive correlation was found between C1, C2, C3 and C4, and a significant positive correlation existed between C2 and C4 (R²=0.98, P<0.01), and C5 and C6 had no correlation with other components, indicating that the sources of DOM components of rural black and smelly water bodies in the city were diverse.