The Properties And Complexation With Metals Of Dissolved Organic Matter From Macrophyte Decomposition In Lake Baiyangdian

Macrophytes cause a large number of decomposition in the winter which increases water turbidity. And this release process adds a large amount of dissolved organic matter (DOM) into the water environment. DOM provides the nutrition for lake, increasing the difficulty of control lake eutrophication. Toxicity, bioavailability and migration of heavy metals in aquatic environment are greatly affected by the presence of dissolved organic matter. In this paper, we studied the effects of decay of macrophytes in Lake Baiyangdian on water environment and the characterizing the release of different plant density of DOM. Moreover, DOM on heavy metals complexation were sucdessfully investigated by excitation-emission matrix fluorescence, parallel factor analysis, and UV-vis absorption spectrum. The research is mainly embodied in the following aspects:The influence of the different plant density of decomposing for water quality was studied. The released of DOC, conductance, TN was different for different plant density, changing with the decay time.This paper researched the structure and composition of DOM from overlying water, using UV-visible absorption spectroscopy, fluorescence spectroscopy. The research is mainly embodied in the following aspects: Higher degree of humification and complex structure were found in sample of the longer decry time. Three protein-like component (C1, C2and C5) and two humic-like components (C3and C4) were identified by PARAFAC model. Using parallel factor combined with principal component analysis found the protein-like play a dominant role in the beginning, however, the effect of humic-like components was important in later decomposing.In the end, the paper analyzed the mechanism of interaction between DOM and metal ions. Four fluorescence components including two humic-like and two protein-like components were identified by PARAFAC model. Protein-like components showed a marked quenching by metal ions, whereas humic-like components showed low quenching effect. Cu complexing capacities and binding affinities are higher than those of the other two heavy metals. Whereas Cd and Zn exhibited a higher quenching effect to protein-like. Meanwhile, the quenching degree is different for different samples. Macrophyte decomposition with different weight gradient impacted the metal ion affinity and quenching effect.2D synchronous fluorescence COS demonstrated that Cd(â…¡) exhibited more binding sites (274,280,344,375,440nm) than Cu(â…¡)(312,395nm). More binding sites of Cd(â…¡) for fulvic acids suggesting fulvic acids might play more important role in DOM binding. We confirmed that2D-COS combined with PARAFAC analysis can provide more information on metal bound to DOM.