[Characterizing Structural Composition of Dissolved and Particulate Organic Matter from Sediment Pore Water in a Urban River Using Excitation-Emission Matrix Fluorescence with Self-Organizing Map].

Excitation-emission matrix (EEM) fluorescence with self-organizing map was applied to characterize structural composition and spatial distribution of dissolved (DOM) and particulate (POM) organic matter from sediment pore water in a typical urban river. Ten sediment pore water samples were collected from the mainstream of Baitabuhe River in Shenyang City of northeast China, along a human impact gradient, i. e. river source, rural and urban regions. DOM and POM were extracted from the pore water, and their EEM fluorescence spectra were measured. ƒ450/500 of DOM ranged from 1.82 to 1.91, indicating that DOM is mainly from microbial source; ƒ450/500 of POM ranged from 1.42 to 1.68, suggesting that POM derived from land. Four components were identified from DOM and POM fractions by self-organizing map, which included tyrosine-like, tryptophan-like, fulvic-like and humic-like matters. Tyrosine-like originated from fresh and less-degraded material with a high potential for oxida- tion, which was considered as representative components of DOM and POM. Tryptophan-like was associated with microbial byproduct-like material, and can indicate microbial activities. The abundance sum of all components in DOM is roughly 2 times more than that in POM. The mean relative abundance of tyrosine-like was more than 50%, while tryptophan-like was about 18.6%-23.1%. Abundance of fulvic-like was much more than that of humic-like, but they were only a small proportion of organic matter fractions. Based on principal component analysis, the characteristics of DOM and POM distinctly were distributed along river source, rural region and urban region, proving that the river was deeply influenced by human activity.

Elemental and spectroscopic methods with chemometric analysis for characterizing composition and transformation of dissolved organic matter during chicken manure composting.

Dissolved organic matter was extracted from chicken manure after 1, 8, 16, 28 and 40 days of composting and characterized by combining elemental and spectroscopic methods with chemometric analysis to investigate the evolution of composting materials. The elemental and spectroscopic analysis results showed that the composting process was characterized by the biodegradation of aliphatics, polysaccharide and proteins, as well as by the synthesis of aromatic structures, humic-like substances and macromolecules. Principal component analysis and correlation analysis indicated that the data from elemental and spectroscopic analysis fell into three main groups, and corresponded to the biodegradation, aromatization, and humification and polymerization state of the composting materials. Hierarchical cluster analysis indicated rapid biodegradation of organic matter during the first eight days, and the formation of aromatic structures, humic-like materials and macromolecules in dissolved organic matter after eight days.

The structure and origin of dissolved organic matter studied by UV-vis spectroscopy and fluorescence spectroscopy in lake in arid and semi-arid region.

To develop a proper indicator which could predict water quality and trace pollution sources is critically important for the management of sustainable aquatic ecosystem. In our study, seven water samples collected from Wuliangsuhai Lake in Inner Mongolia were used. UV-visible spectra and synchronous fluorescence spectra were applied to investigate the humification degree and aromatic structure of dissolved organic matter (DOM) extracted from water samples. The results showed that both samples from W1 site and W3 site display lower humification degree and less aromatic structure, where industrial wastewater and domestic sewage, and reclaimed water of farmland irrigation, were accepted respectively. After computing the values of SUVA(254), A(280), A(250/365), A(253/203) and A(226-400), we reached the conclusion that they have a consistent trend (W4> W6> W5> W2> W7> W1> W3). Fluorescence index (f(450/500)) was always utilised to interpret the origin of organic matter in a complex aquatic environment system. Values of f(450/500) are closer to 1.60, indicating that humic substances derived from terrestrial sources and biological sources. Our study demonstrated that reclaimed water of farmland irrigation, industrial wastewater and domestic sewage will definitely influence the humification degree and amount of the aromatic structure of DOM.

[Study on solid surface fluorescence characteristic of saline soils around lakes in arid and semiarid regions].

Fluorescence spectroscopy relies on the fluorescence emitted by rigid conjugated systems and thus has been increasingly used to assess the soil organic matter (SOM) humification. This technique is widely applied to solution samples of humic substances, and so far no information exists about its applicability to solid-phase soil samples. Composite soil samples of different depths (0-20, 20-40 and 40-60 cm) were collected from four different halophyte communities along a saline-impact gradient, namely, Comm. Salicornia europaea (CSE), Comm. Suaeda glauca (CSG), Comm. Kalidium foliatum (CKF) and Comm. Sophora alopecuroides (CSA) located around Wuliangsuhai Lake. A humification index based on solid surface fluorescence spectroscopy (HIX(SSF)) was proposed, and compared with conventional humification indices I400/I360, I470/I360, I465/I399 and A4 /Al. There were close positive linear correlations between HIXass and 1400/1360, 145/I399 and A4/A1, but a poor positive linear correlation existed between the HIX(SSF) and I470/I360. The results indicated that HIX(SSF) can be taken as a tool to assess the soil humi fication. The HIX(SSF) of the CSE and CSG varied inappreciably within soil profiles and there was no trend with depth. However the HIX(SSF) varied appreciably in the CKF and CSA, and the HIX(SSF) of the bottom soil profile was higher than that of the other profiles. As a whole, the soil humification degree was low around Wuliangsuhai Lake, and the ecological environment was relatively fragile. The salinity showed a strong negative linear relationship with the I400/I360, I470/I360, I465/I399 and A4/A1, but a good negative linear relationship with the HIX(SSF). The results indicated that the degree of the SOM humification increased with the drop in the salinity. The HIX(SSF) can be an indicator not only of the degree of SOM humification, but also of the process of the salinisation.

[Quantitative fluorescence characterization of organic matter stability during chicken manure composting].

Due to its high sensitivity, good selectivity and nondestructive nature, fluorescence spectroscopy was widely applied to characterize the nature of dissolved organic matter (DOM) from different source since the last decade. In the present study, dissolved organic matter (DOM) extracted from chicken manure samples during composting progress was quantitatively characterized by fluorescence analysis techniques and mathematical analysis methods. The results showed that, the ratio between the fluorescence intensities at 330 nm (humic-like matter) and 280 nm(protein-like matter) (I330/I280) in synchronous-scan excitation mode spectra, the area of a fluorescence spectrum obtained by excitation at the blue wavelength of 465 nm(A470-640), and the ratio between the area of the last quarter (435-480 nm) and the area of the first quarter (300-345 nm) of the emission spectrum (A435-480 nm/A300-345 nm) by exciting the sample with ultraviolet radiation of 240 nm, all increased during composting, and the humification degree of compost increased as well. Three-dimensional excitation emission matrix fluorescence spectroscopy showed that the intensity of protein-like matter decreased during composting progress and diminished at the end, while that of fulvic-like matter increased all the time. The ratio between the intensity of the ultraviolet fulvic-like fluorescence (Peak A) and that of the visible fulvic-like fluorescence gamma (A, C) showed an overall significant downward trend during composting, but fluctuated in the progress. The correlation analysis showed that, I330/I280, A470-640 and A435-480 nm/A300-345 nm were all significant correlative, while gamma (A, C) was not correlative with the above-mentioned three parameters at 0. 05 level due to effect by other factors. The results show that, I330/I280, A470-640 and A435-480 nm/A300-345 nm can be effectively used in the process of the evaluation of humification degree during composting.

[UV-Visible Spectra Properties of DOM from Taizi River in Benxi City Section by Multivariable Analysis].

This study investigated the ability of ultra violet-visible (UV-Visible) spectroscopy to analyze the origin,compositions,structure and humification level of dissolved organic matter(DOM). Seven surface water samples were collected from the Benxi City section of mainstream in Taizi River. Nine indices (SUVA254, E2/E3, E2/E4, E4/E6, S275-295, S350-400, A2/A1, A3/A1 and A3/A2), deduced from elemental analysis and UV visible spectroscopy of DOM, were used to assess the humification degree. The results showed that the characteristics of DOM were distributed along urban river and industrial wastewater discharge, and the DOM of waste water from Benxi steel plant contained a low degree of condensation of small organic molecules. E2/E3 showed positive correlation with E2/E4, and negative correlations with S275-295, S350-400, A2/A1,indicating that humification degree of DOM was not only concerned with the degree of condensation of organic molecules, but also closely associated with the ratio between humic acid and fulvic acid. Composition structure of DOM showed significant positive correlations with A2/A1, SUVA254 and S275-295, and significant negative correlations with E2/E3 and E2/E4. Based on the loadings of DOM component and scores plot of sampling sites in Taizi River (Benxi City section),the characteristics of DOM were distinctly distributed along urban river and industrial wastewater discharge, proving that the river was deeply influenced by human activity.

[Effects of land management measures on nutrients emission].

The SWAT model, coupled with a GIS, was applied to simulate the effects of fertilizer application, contour planting and returning land for farming to forestry on nutrients discharges. The results showed that when nitrogen fertilizer of agricultural land increased from 630 to 955 kg/hm2, and phosphorus fertilizer increased from 200 to 300 kg/hm2, nitrogen and phosphorus nutrient emissions have shown a growing trend. Nitrate nitrogen loads reached to 3 776.59 kg which increased 19.7% and the rate of changes was the largest. The change rate of inorganic phosphorus was the smallest which increased only 2.7%. The impact of emission loads on nitrogen and phosphorus was the smallest if contour planting was adopted. When slope farmland which slope is greater than 25% all returned land for farming to forestry, the emission loads of various forms of nitrogen and phosphorus decreased, organic phosphorus decreased 16.3% among them. Organic nitrogen, ammonia nitrogen and inorganic phosphorus compared with before returning land for farming to forestry, decreased 22.7%, 25.4% and 27.9% respectively. In small basin of Zhangjiachong, returning farmlands to forests and reducing the amount of chemical fertilizer on the slope farmlands which slopes are larger than 25% have played a prominent role.