Investigating the composition characteristics of dissolved and particulate/colloidal organic matter in effluent-dominated stream using fluorescence spectroscopy combined with multivariable analysis.

Fluorescence excitation-emission matrix (EEM) spectroscopy combined with principal component analysis (PCA) and parallel factor analysis (PARAFAC) were used to investigate the compositional characteristics of dissolved and particulate/colloidal organic matter and its correlations with nitrogen, phosphorus, and heavy metals in an effluent-dominated stream, Northern China. The results showed that dissolved organic matter (DOM) was comprised of fulvic-like, humic-like, and protein-like components in the water samples, and fulvic-like substances were the main fraction of DOM among them. Particulate/colloidal organic matter (PcOM) consisted of fulvic-like and protein-like matter. Fulvic-like substances existed in the larger molecular form in PcOM, and they comprised a large amount of nitrogen and polar functional groups. On the other hand, protein-like components in PcOM were low in benzene ring and bound to heavy metals. It could be concluded that nitrogen, phosphorus, and heavy metals in effluent had an effect on the compositional characteristics of natural DOM and PcOM, which may deepen our understanding about the environmental behaviors of organic matter in effluent.

[Complexation Between Copper(â ¡) and Colored Dissolved Organic Matter from Municipal Solid Waste Landfill].

In order to elucidate the evolution mechanism of heavy metal species in landfill cells, three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM), fluorescence quenching titration and parallel factor analysis (PARAFAC) were employed to study the complexation process between Cu(Ⅱ) and colored dissolved organic matter (CDOM) from landfill with different ages. The experimental results indicated that the landfilled CDOM comprised protein-like, humic-like and fuvic-like matter. The relative content of protein-like matter decreased during the landfill process, whereas the humic-like and fuvic-like matter increased during the process. The range of the conditional stability constants and the percentage of fluorophores participated the complextion between Cu(Ⅱ) and protein-like matter with different ages were 4.00-5.75 and 22.78%-95.30%, respectively. Those parameters changed slightly for humic-like matter with different ages, which ranged from 4.71 to 5.54 and from 42.35% to 61.46%, respectively. As regard to fulvic-like matter, those parameters were 4.44-5.25 and 46.14%-57.22%, respectively. The complexation ability of humic-like substances with Cu(Ⅱ) decreased during the landfill process, though the percentage of fluorophores participated the complexation increased. The complexation ability of humic-like substances with Cu(Ⅱ) was stronger than that of fulvic-like matter, though the percentage of fluorophores participated the complexation in humic-like matter was low compared with fulvic-like matter.

[Composition, Evolution, and Complexation of Dissolved Organic Matter with Heavy Metals in Landfills].

Samples of wastes and leachates were collected from a landfill site and a leachate treatment plant[i.e., equalization basin, anaerobic zone, oxidation ditch, and membrane bioreactor (MBR) section]. Dissolved organic matter (DOM) was extracted from the wastes and leachates, and its composition, evolution, and complexation characteristics with heavy metals were studied using UV-Visible and fluorescence spectroscopy combined with1H nuclear magnetic resonance. The aliphatic compounds were found to be the main substances in DOM in the fresh landfill wastes (<5 a), and the relative content of aromatics and substituent groups, i.e., carbonyl, hydroxyl, and carboxyl functional groups, decreased during the initial process. On the other hand, carbohydrates and organic amines were observed to be the main substances in DOM obtained from the intermediate and old landfill wastes (>5 a), and the relative content of aromatics and substituent groups (carbonyl, hydroxyl, and carboxyl functional groups) increased persistently during the process of organic matter humification. The aliphatics, carbohydrates, and organic amines all existed in DOM from the equalization basin Carbohydrates and aromatic compounds increased rapidly after the anaerobic, aerobiotic, and membrane treatment. However, low molecular weight organic matter and alkyl chain substances decreased during the leachate treatment process and the side chain of the aliphatics was shortened despite the increase in its content. The distribution of zinc in the wastes and leachates was influenced by the complexation with the nitrogen-and oxygen-containing functional groups, whose effect on other metals was not obvious.

Novel method of vulnerability assessment of simple landfills area using the multimedia, multipathway and multireceptor risk assessment (3MRA) model, China.

Vulnerability assessment of simple landfills was conducted using the multimedia, multipathway and multireceptor risk assessment (3MRA) model for the first time in China. The minimum safe threshold of six contaminants (benzene, arsenic (As), cadmium (Cd), hexavalent chromium [Cr(VI)], divalent mercury [Hg(II)] and divalent nickel [Ni(II)]) in landfill and waste pile models were calculated by the 3MRA model. Furthermore, the vulnerability indexes of the six contaminants were predicted based on the model calculation. The results showed that the order of health risk vulnerability index was As > Hg(II) > Cr(VI) > benzene > Cd > Ni(II) in the landfill model, whereas the ecology risk vulnerability index was in the order of As > Hg(II) > Cr(VI) > Cd > benzene > Ni(II). In the waste pile model, the order of health risk vulnerability index was benzene > Hg(II) > Cr(VI) > As > Cd and Ni(II), whereas the ecology risk vulnerability index was in the order of Hg(II) > Cd > Cr(VI) > As > benzene > Ni(II). These results indicated that As, Hg(II) and Cr(VI) were the high risk contaminants for the case of a simple landfill in China; the concentration of these in soil and groundwater around the simple landfill should be strictly monitored, and proper mediation is also recommended for simple landfills with a high concentration of contaminants.

Heterogeneity of the electron exchange capacity of kitchen waste compost-derived humic acids based on fluorescence components.

Composting is widely used for recycling of kitchen waste to improve soil properties, which is mainly attributed to the nutrient and structural functions of compost-derived humic acids (HAs). However, the redox properties of compost-derived HAs are not fully explored. Here, a unique framework is employed to investigate the electron exchange capacity (EEC) of HAs during kitchen waste composting. Most components of compost-derived HAs hold EEC, but nearly two-thirds of them are found to be easily destroyed by Shewanella oneidensis MR-1 and thus result in an EEC lower than the electron - donating capacity in compost-derived HAs. Fortunately, a refractory component also existed within compost-derived HAs and could serve as a stable and effective electron shuttle to promote the MR-1 involved in Fe(III) reduction, and its EEC was significantly correlated with the aromaticity and the amount of quinones. Nevertheless, with the increase of composting time, the EEC of the refractory component did not show an increasing trend. These results implied that there was an optimal composting time to maximize the production of HAs with more refractory and redox molecules. Recognition of the heterogeneity of EEC of the compost-derived HAs enables an efficient utilization of the composts for a variety of environmental applications. Graphical abstract Microbial reduction of compost-derived HAs.

[Evolution of Dissolved Organic Matter Properties in a Constructed Wetland of Xiao River, Hebei].

The evolution of water DOC and COD, and the source, chemical structure, humification degree and redox of dissolved organic matter (DOM) in a constructed wetland of Xiao River, Hebei, was investigated by 3D excitation--emission matrix fluorescence spectroscopy coupled with ultraviolet spectroscopy and chemical reduction, in order to explore the geochemical processes and environmental effects of DOM. Although DOC contributes at least 60% to COD, its decrease in the constructed wetland is mainly caused by the more extensive degradation of elements N, H, S, and P than C in DOM, and 65% is contributed from the former. DOM is mainly consisted of microbial products based on proxies f470/520 and BIX, indicating that DOM in water is apparently affected by microbial degradation. The result based on PARAFAC model shows that DOM in the constructed wetland contains protein-like and humus-like components, and Fulvic- and humic-like components are relatively easier to degrade than protein-like components. Fulvic- and humic-like components undergo similar decomposition in the constructed wetland. A common source of chromophoric dissolved organic matter (CDOM) and fluorescent dissolved organic matter (FDOM) exists; both CDOM and FDOM are mainly composed of a humus-like material and do not exhibit selective degradation in the constructed wetland. The proxies E2 /E3, A240-400, r(A, C) and HIX in water have no changes after flowing into the constructed wetland, implying that the humification degree of DOM in water is hardly affected by wet constructed wetland. However, the constructed wetland environment is not only beneficial in forming the reduced state of DOM, but also facilitates the reduction of ferric. It can also improve the capability of DOM to function as an electron shuttle. This result may be related to the condition that the aromatic carbon of DOM can be stabilized well in the constructed wetland.

Insight into the composition and degradation potential of dissolved organic matter with different hydrophobicity in landfill leachates.

Dissolved organic matter (DOM) isolated from the leachates with different landfill ages was fractionated into hydrophobic acid (HOA), hydrophobic neutral (HON), hydrophobic base (HOB) fractions and hydrophilic matter (HIM) based on hydrophobicity, and the composition and degradation potential of the bulk DOM and its fractions were investigated by excitation-emission matrix fluorescence spectra coupled with parallel factor analysis. Results showed that the bulk DOM comprised fulvic-, humic-, tryptophan- and tyrosine-like substances, as well as component C1, whose composition and origin was unidentified. Landfill process increased the content of component C1, fulvic- and humic-like matter. The HON fractions comprised primarily component C1 and tyrosine-like matter. The HOA, HOB and HIM fractions isolated from the young leachates consisted mainly of tryptophan- and tyrosine-like substances. As to the intermediate and old leachates, the HOA and HOB fractions comprised mainly component C1, while the HIM comprised mainly fulvic-like matter. The HIM showed the most resistant against biodegradation among the four fractions, and was the main component of leachate treatment. Advanced oxidation and/or membrane treatment are recommended to remove the HIM fraction due to its hydrophilic and stable characteristics.

[Composition and Evolution Characteristics of Dissolved Organic Matter During Composting Process].

According to the fraction method presented by Leenheer, dissolved organic matter (DOM) extracted from chicken manure with different composting time was fractionated into five groups [i. e., hydrophobic acid (HOA), hydrophobic base (HOB), hydrophobic neutral (HON) fractions, acid-insoluble (AIM) and hydrophilic matter (HIM)] using the XAD-8 resin based on its polarity and electric charge characteristics. The composition and structures of these fractions were investigated by elemental analysis, FTIR and 1H-NMR spectra. The results showed that the HIM and HOA fractions accounted for 32%-44% and 35%-47% of DOM, respectively, during the composting process, while the sum of the fractions HOB, AIM and HON was responsible for less than 25% of DOM. The HIM content decreased while the hydrophobic component increased after composting. The elemental analysis indicated that, during the composting process, the N, C, S content of all five fractions increased, the H/C ratio decreased, but the humification degree increased; The result from 1H-NMR analysis showed that the HIM had low alkyl chain, short branched chain, high branches and carbohydrate structure, which was opposed to the HON fraction. The composition of AIM was similar to that of humic acids, while the HOB was rich in nitrogen-containing compounds. The result from the FTIR analysis showed that the HOA and HOB fractions were rich in abundant carboxyl, ester group and hydroxyl functional group. Besides the above functional groups, the AIM and HIM were rich in benzene groups. The HON fraction was rich in aliphatic functional group except for the abovementioned functional groups. The aliphatic functional group was degraded and the benzene functional group after composting.

[Vertical Distribution Characteristics of Dissolved Organic Matter in Groundwater and Its Cause].

Dissolved organic matter (DOM) can change the species, migration and transformation of foreign pollutants in groundwater, and the investigations of its composition and distribution characteristics play a role in environment protection. The groundwater DOMs were obtained at the depths of 1.2, 1.5 and 1.8 m, and its origin, composition, concentration, distribution characteristics and influencing factors were studied using UV-Vis and fluorescence spectra combined with parallel factor analysis and principle components analysis. The results showed that, DOM in the groundwater originated from both terrigenous input and microbial activities, and was comprised of humic-like matter, heterogeneous component, and protein-like matter. Humic-like matter and heterogeneous components showed a high concentration at 1.5 m and a low one at 1.2 m, whereas the protein-like matter exhibited a low concentration at 1.5 m and a high one at 1.2 m. The groundwater DOM at 1.5 m exhibited the highest aromaticity, humification, molecular weight and polar functional group content, while that at 1.2 m depth showed the lowest aromaticity, humification, molecular weight and polar functional group content. The vertical distribution of DOM in groundwater was related to aromaticity, humification, molecular weight and polar functional group, and the DOM with high aromaticity, humification, molecular weight and polar functional group resisted to biodegradation, and could easily enter into the bottom layer groundwater.

Insight into the composition and evolution of compost-derived dissolved organic matter using high-performance liquid chromatography combined with Fourier transform infrared and nuclear magnetic resonance spectra.

Size exclusion chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC) were combined with Fourier transform infrared spectra (FTIR) and nuclear magnetic resonance (NMR) based on two dimensional (2D) hetero-spectral correlation spectra techniques to fractionate compost-derived dissolved organic matter (DOM) and determine how size- and hydrophobicity-distinguished fractions differ in the composition and evolution. The results showed that the compost-derived DOM was comprised of protein- and humic-like species. The low apparent molecule weight (AMW) protein-like components were enriched in C-C=H3 and N-C=O, and showed more bioreactivity compared with the high AMW counterpart. The hydrophobic and hydrophilic protein-like components both consisted of CCH3 and N-C=O. However, the relatively hydrophilic protein-like components were more easily consumed. As to the humic-like species, the relatively hydrophilic components were slightly larger than the relatively hydrophobic ones. The high AMW and relatively hydrophilic humic-like components were high in C-H, OCH3, N-C=O, N-H, COO, O-H and aromatic C. The low AMW and relatively hydrophobic humic-like components were enriched in CCH3 and N-C=O, and were easily biodegraded during composting. 2D hetero-spectral correlation spectra techniques enhance the characterization of DOM and provide a promising way to elucidate the environmental behaviors of DOM.

[Spectral Characteristic of Dissolved Organic Matter in Xiaohe River, Hebei].

The spectral characteristic of dissolved organic matter (DOM) in Xiaohe River, Hebei, was investigated by fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, and basic chemical water quality indicators. The data was then statistical analyzed using principal component analysis and correlation analysis method. The result based on 3D excitation-emission matrix fluorescence spectroscopy showed that DOM in Xiaohe River contained both protein-like and humus-like components. DOM and N-containing compounds were obviously correlated with COD, especially between NH4+ -N and humic-like component, indicating that COD of water in Xiaohe River can be reduced by removing NH4+ -N and DOM, which could be good indicators for monitoring water quality in the future. The relative content of protein-like component reduces gradually along the downstream, while that of humic-like component showed an increasing trend. DOM in samples S1 and S2 was mainly consisted of humic-like components with larger molecular weight and higher aromaticity, while that in samples S3 and S6 was mainly consisted of protein-like components with smaller molecular weight, lower aromaticity, which are easier to be degraded. Therefore, in order to enhance the remove of refractory humic-like substances, sewage treatment plants of S1 and S2 or improved membrane treatment equipment with better removal effect of macromolecules should be provide. On the other hand, the anaerobic and aerobic biological treatment processes should be optimized in S3 and S6, so as to better remove these degradable protein-like substances.

Composition, removal, redox, and metal complexation properties of dissolved organic nitrogen in composting leachates.

This study investigated the composition, removal, redox, and metal complexation characteristics of dissolved organic nitrogen (DON) in composting leachates. Results showed that the leachate-derived DON comprised proteinaceous compounds and amines, and most of them were integrated into the fulvic- and humic-like substances. Neutral, basic, acidic, hydroxylic, aromatic, and sulfuric amino acids all were detected in the influent leachates. However, most of them were removed by the biological and physical processes, and only neutral amino acids were detected in the effluent. The DON was not the main contributor to the redox capability of the leachate dissolved organic matter (DOM). However, it exhibited a strong capability for metal complexation. The amines formed strong complexes with the metals Mo, Co, Cr, and Ni, while the proteinaceous matter interacted with the metals Cr and Ni.

Using fluorescence spectroscopy coupled with chemometric analysis to investigate the origin, composition, and dynamics of dissolved organic matter in leachate-polluted groundwater.

Groundwater was collected in 2011 and 2012, and fluorescence spectroscopy coupled with chemometric analysis was employed to investigate the composition, origin, and dynamics of dissolved organic matter (DOM) in the groundwater. The results showed that the groundwater DOM comprised protein-, fulvic-, and humic-like substances, and the protein-like component originated predominantly from microbial production. The groundwater pollution by landfill leachate enhanced microbial activity and thereby increased microbial by-product-like material such as protein-like component in the groundwater. Excitation-emission matrix fluorescence spectra combined with parallel factor analysis showed that the protein-like matter content increased from 2011 to 2012 in the groundwater, whereas the fulvic- and humic-like matter concentration exhibited no significant changes. In addition, synchronous-scan fluorescence spectra coupled with two-dimensional correlation analysis showed that the change of the fulvic- and humic-like matter was faster than that of the protein-like substances, as the groundwater flowed from upstream to downstream in 2011, but slower than that of the protein-like substance in 2012 due to the enhancement of microbial activity. Fluorescence spectroscopy combined with chemometric analysis can investigate groundwater pollution characteristics and monitor DOM dynamics in groundwater.

Insight into the evolution, redox, and metal binding properties of dissolved organic matter from municipal solid wastes using two-dimensional correlation spectroscopy.

Two-dimensional correlation spectroscopy was employed to investigate the evolution, redox, and metal binding properties of dissolved organic matter (DOM) from municipal solid wastes (MSWs) during composting. The results showed that the DOM was degraded during composting in the order of aliphatic substances > proteinaceous compounds > cellulose, hemicellulose and lignin, while humic substances transformed during the process in the order of fulvic-like matter > humic-like substances > protein-like matter. The fulvic- and humic-like substances originated from lignin and polysaccharide-like substances with the function groups of CH3, CCH2, CCH, OCH3, OCH, O--C--O, aromatic C, and COO, while the protein-like matter was derived from aliphatic and proteinaceous compounds with the functional groups of CCH3 and N--C==O. The aromatic C and COO were responsible for the oxidation capacity of the MSW-derived DOM, while the O--C--O and COO accounted for the Cu and Zn binding capacity of the DOM.

[Study on ecoregion techniques of lake nutrients in Yunnan-Guizhou plateau Lake regions].

The primary objective of this research is to present an ecoregion model based on the principle components analysis (PCA), the cluster analysis (CA), the discriminant analysis (DA) and the spatial autocorrelation analysis (SAA), which were applied to establish the ecorigion of lake nutrients in Yunnan-Guizhou Plateau Lakes. First, the principle components analysis method was used not only to reduce the dimensionality of the feature space, but also to deal with new indexes. The accumulation contribution ratio of the four new indexes achieved 93.69%, which had the full representation. These complementary indexes which reflect the conditions of lakes were helpful to establish the index system of ecorigion of lake nutrients in Yunnan-Guizhou Plateau Lakes. Second, initial classification of lake drainage area was accomplished by new indicator values and cluster analysis which contained five classes, and then the categories of non-lake drainage area could be identified by the discriminant analysis. Finally, the cluster result was carried on the global statistics, Moran's I was 0.32 which was higher than 0, and the examination value Z was 68.28 which was higher than marginal value (remarkable level 1% correspond 2.58), it was indicated that the cluster result and the space position had the remarkable relativity, afterward spatial distribution pattern of the region was achieved by the quantificational analysis about over score of principle components and application of local spatial autocorrelation method. Then the ecorigion of lake nutrients was accomplished by the association and difference between different districts of the scattered regions' s spatial character. These results indicated that the ecoregion model initiated in the paper was appropriate and feasible to receive objective results and avoid artificial factors. Also it has provided a new method to explore the index system and techniques about the ecoregion of lake nutrients. Scientifically, the model was in favor of the foundation of lake nutrient criteria and eutrophication control standards in China.

[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.

Spatial variability of organochlorine pesticides (DDTs and HCHs) in surface soils from the alluvial region of Beijing, China.

The spatial variability in the concentrations of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane (DDT) in surface soils was studied on the basis of the analysis of 131 soil samples collected from the surface layer (0-20 cm depth) of the alluvial region of Beijing, China. The concentrations of total HCHs (including alpha-, beta-, gamma-, and delta-isomers) and total DDTs (including p,p'-DDT, p,p'-DDD, p,p'-DDE, and o,p'-DDT) in the surface soils tested were in the range from nondetectable to 31.72 microg/kg dry soil, with a mean value of 0.91, and from nondetectable to 5910.83 microg/kg dry soil, with a mean value of 32.13, respectively. It was observed that concentrations of HCHs in all soil samples and concentrations of DDTs in 112 soil samples were much lower than the first grade (50 microg/kg) permitted in "Environment quality standard for soils in China (GB15618-1995)". This suggests that the pollution due to organochlorine pesticides was generally not significant in the farmland soils in the Beijing alluvial region. In this study, the spatial distribution and trend of HCHs and DDTs were analyzed using Geostatistical Analyst and GS+(513). Spatial distribution indicated how these pesticides had been applied in the past. Trend analysis showed that the concentrations of HCHs, DDTs, and their related metabolites followed an obvious distribution trend in the surface soils from the alluvial region of Beijing.