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Dissolved organic matter （DOM） plays an important role in indicating the pollution of the water environment, and sediment is the main source of endogenous pollution of the water environment. Research on the spectral characteristics of DOM in sediments was important for the interpretation of water environment pollution. In this study, UV-visible absorption spectroscopy and three-dimensional fluorescence spectroscopy combined with the parallel factor analysis （PARAFAC） were used to analyze the fluorescent components, sources, and influencing factors of DOM in sediments from the Yuanhe River Basin. The results showed that the average of ω （TN）, ω （TP）, and ω （OM） in sediments from the Yuanhe River Basin were 0.52, 0.66, and 21.22 g·kg -1 , respectively. The concentrations of total nitrogen and total phosphorus increased along the flow direction. In addition, the sediment DOM from the Yuanhe River Basin mainly originated from terrestrial sources. The chromophoric DOM concentration and aromaticity of DOM from the downstream reaches were significantly higher than those from the upstream and midstream reaches. Based on PARAFAC, four fluorescent components of DOM in sediments from the Yuanhe River Basin were identified, including three humus-like components （C1, C3, and C4） and one protein-like component （C2）. The sediment DOM was dominated by humus-like materials. Moreover, the fluorescent intensity of the fluorescent components was higher in the downstream reaches. Redundancy analysis revealed that the physicochemical properties of sediments in the mainstream and downstream reaches played a more significant role in the spectral properties of DOM. Phosphorus pollution and the terrestrial humus-like substance of sediment DOM were homologous. These results indicated that the spectral properties of DOM were the indicator of water environmental pollution in the region with strong anthropogenic influence.

Wetland plant diversity reveals key aspects of the environmental and ecological status of wetlands and plays an important role in the maintenance of ecosystem functions and services. The present study surveyed the plant species diversity of 22 wetlands in Beijing and, combining field data and remote sensing data, evaluated ecological qualities of the wetlands based on indicators of habitat status, plant species diversity, typical wetland plant community, and status of alien plant invasion. A total of 338 species (including varieties and subspecies) belonging to 220 genera of 74 families of wetland plants were recorded in Beijing. The wetlands could be divided into four types according to plant species composition, which showed a spatial gradient pattern from urban core to ecological conservation areas. Wetlands located in ecological conservation areas were of better ecological quality than those located in urban core and suburban plain areas. The value of ecological quality index (EQI) for Baihe River, Huaishahe-Huaijiuhe River, Jinniu Lake, Hanshiqiao Wetland, and Yongdinghe River (Mentougou Section) were in the top five, whereas the value of EQI for river-type wetlands located in suburban plain areas were relatively lower. The results of the canonical correspondence analysis indicated that the most critical factors affecting wetland plant species composition were the distance to the nearest road, water total nitrogen, and area percentage of ecological green land. Furthermore, the results of the canonical correlation analysis indicated that the most critical factors affecting wetland plant species diversity were the area percentage of construction land and water total organic carbon. Human activity intensity and water quality have a strong impact on the plant diversity and ecological quality of wetlands in Beijing. It is suggested that efforts should be made to strengthen the ecological protection and restoration of the river-type wetlands located in suburban plain areas.

The composition of municipal solid waste (MSW) in landfills is complex; additionally, the waste stored in landfills continues to generate greenhouse gases, odors, and ground water pollutants even during the post-closure stage. Therefore, landfills are considered key fields of urban eco-environmental remediation. In this context, it is crucial to understand the storage, composition, physical, and chemical characteristics of waste, as well as its potential environmental impacts. However, very few studies have discussed these topics in detail. In this work, we focused on the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), which has the highest urbanization rate and population density of all China. The generation, stock, physical components, and key elements of MSW in eleven cities of the GBA were analyzed based on both the scientific literature and statistical data. The main results are as follows:① the total amount of MSW produced by the cities was of 26.4 Tg in 2017, with an average annual increment of 0.8 Tg; moreover, the most used disposal method was the sanitary landfill (58.9% of the total); ② the total amount of MSW disposed in the landfills was equal to 230.1 Tg[including mainly food waste (109.6 Tg), plastic (38.9 Tg), and paper (29.6 Tg)]; ③ between 2001-2017, a total of 50.0 Tg of carbon were input in the landfills in the form MSW, of which 7.1 Tg of carbon were emitted as gas and 1.5 Tg were discharged as leachate; moreover, the total landfill carbon stock was equal to 41.4 Tg. Overall, this study provides fundamental data that can be used to determine the environmental impacts of MSW landfills and implement the eco-environmental remediation of urban landfill sites in the GBA.

In order to evaluate the effect of grazing on the mechanism for greenhouse gas emissions in the seasonal frozen soils for a typical steppe in Inner Mongolia, variations of N 2 O and CO 2 concentrations in different soil layers were monitored by an in situ gas collection system. Three conditions were selected:ungrazed since 1979 (UG79), ungrazed since 1999 (UG99), and continuously grazed (CG). The results showed that the profile soil N 2 O and CO 2 concentrations demonstrated a significant spatio-temporal distribution. ① The average concentrations of CO 2 in the soil profile of the three conditions were:CO 2 in the growth period > in the freezing-thawing period > in the freezing period. The CO 2 concentrations in the growing period were much higher than in the freezing-thawing period and freezing period. The CO 2 concentration was the highest in the UG79, and the lowest was in the CG. The concentration of CO 2 in different soil layers was ordered as 20 cm ≥ 50 cm ≥ 35 cm ≥ 10 cm ≥ 5 cm at the UG79 and UG99 sites, and 50 cm ≥ 35 cm ≥ 20 cm ≥ 10 cm ≥ 5 cm at the CG site. ② The spatial and temporal variation of N 2 O concentration in the soil profile was different from that of CO 2 . While the UG79 and UG99 sites showed a "single peak type" change, the CG site had a "bimodal" pattern. The N 2 O concentration of the three conditions increased sharply during the soil freezing-thawing period, and the N 2 O was also released weakly during the growing season at the CG site ( P <0.05). The average N 2 O concentration of the CG was significantly higher than that of UG79 and UG99 ( P <0.05). The results show that the concentration of N 2 O in different soil layers was ordered as follows:UG79:20 cm ≥ 50 cm ≥ 35 cm ≥ 10 cm ≥ 5 cm; CG:50 cm ≥ 35 cm ≥ 20 cm ≥ 10 cm ≥ 5 cm, and UG99:35 cm ≥ 50 cm ≥ 20 cm ≥ 10 cm ≥ 5 cm. The results concluded that grazing decreased the profiled soil CO 2 concentration and increased N 2 O concentration, which provides a basis for the accurate estimation of greenhouse gas emissions in the seasonal frozen soil in grasslands.

Carbon storage in the Loess Plateau is affected by land use. In order to assess the differences in soil organic carbon (SOC) and soil inorganic carbon (SIC) under different land use patterns in deep soil profiles, we investigated the distribution characteristics of SOC and SIC at 0-20.0 m soil depth at three locations in the northern Shaanxi province (i.e., an economical plantation in Mizhi, a reforestation area in Shenmu, and a wind break and sand fixation forest district in Yuyang). The results showed that the order for SOC content was:pruning jujube tree (2.00 g·kg -1 ) > jujube tree (1.54 g·kg -1 ) > Caragana (0.97 g·kg -1 ) > degraded artificial grassland (0.81 g·kg -1 ) > pine forests (0.70 g·kg -1 ) > natural grass field (0.45 g·kg -1 ), which indicated significant differences between SOC content and land use types ( P <0.05). Similarly, the order of SIC content was:pruning jujube tree (11.66 g·kg -1 ) > jujube tree (11.59 g·kg -1 ) > Caragana (9.62 g·kg -1 ) > degraded artificial grassland (8.07 g·kg -1 ) > pine forests (4.32 g·kg -1 ) > natural grass field (0.47 g·kg -1 ). There were no significant differences between SIC content and soil profiles under the economical plantation of Mizhi and the reforestation area of Shenmu. There were significant differences for SIC content between an artificial economic forest, an area returning farmland to a forest (grass) profile, and a windbreak and sand fixation forest ( P <0.05). The SIC densities for pruning jujube tree, jujube tree, Caragana, degraded artificial grassland, pine forest, and natural grass field were 6.19, 7.71, 10.70, 10.78, 5.91, and 1.03 times that of its corresponding SOC density, respectively. It has been concluded that the soil carbon storage was significantly different for different land use patterns, and the SIC content was much higher than the SOC content in the soil profile.

Chongqing Laolongdong and Qingmuguan karst underground rivers were selected as the research objects, and 21 kinds of OCPs in those two underground rivers were analyzed by gas chromatography (GC-μECD). The results showed that, o,p '-DDE, p,p '-DDE, o,p '-DDD were not detected in Nanshan and Qingmuguan underground rivers; o,p '-DDT and dieldrin were not detected in Qingmugang; but the detection rate of the rest of the OCPs in those two underground rivers was as high as 100%. HCHs and ALDs were the most dominant compounds in Laolongdong underground river, whereas HCHs and methoxychlor were the most dominant compounds in Qingmuguan. The concentration range of total OCPs in Qingmuguan was 145-278 ng·L -1 with a mean value of 213 ng·L -1 . The concentration range of total OCPs in Laolongdong was 17.7-40.8 ng·L -1 with a mean value of 32.7 ng·L -1 . The OCPs component showed an increasing trend from the entrance to the exit of those two underground rivers. By analyzing the source of OCPs pollution, DDTs in the two underground river basin came from the historical industrial DDTs input; chlordane mainly came from atmospheric deposition. HCHs was the main source of Lin Dan's input, Nanshan underground river was historical pollution, whereas there was a new HCHs input from Ganjiachao in Qingmuguan upstream. Compared with the water bodies at home and abroad, the concentrations of HCHs and DDTs in Nanshan underground river water were at low level, whereas those in Qingmuguan were at medium to high level. Comparing with the hygienic standard of foreign water, it could be observed that Nanshan underground river and Qingmuguan underground river were not able to meet the standard of drinking water safety standard. For the sake of protecting the ecological environment of the underground river, land application of organic chlorine pesticide should be banned in Qingmuguan.

Fatty acids were quantitatively analyzed by gas chromatography-mass spectrometer (GC-MS). Dissolved fatty acids were collected from Nanchuan epikarst spring. The results of BQ, LQ, HQ showed that the average contents of fatty acids were 14870, 12912 and 8801 ng·L -1 from May to July, respectively, and followed the order of SFA> MUFA> BrFA> PUFA. The monomers with highest content were C16:0 and C18:0. From May to July, the fatty acid content increased in BQ , LQ, HQ. The differences in vegetation coverage and bedrock bare rate, as well as the interaction of the dilution effect and soil transfer increase, led to the changes in content and the composition of the fatty acids. Based on the molecular characteristic indices of fatty acids, like H/L, CPI h , TAR FA about BQ, LQ, HQ, and contents of fatty acids which were mainly originated from bacteria, phytoplankton or terrigenous higher plant, it was indicated that fatty acids were mainly originated from higher plant in LQ in May, from phytoplankton input in HQ in July, while from bacteria in the other months in LQ, HQ and from May to July in BQ.

In order to explore the contents, composition, distribution characteristics, sources and pollution level of polycyclic aromatic hydrocarbons(PAHs) and fatty acids in water of Qingmuguan karst underground river in Chongqing, water samples were respectively collected from underground river in rainy season and dry season, 2013 and polycyclic aromatic hydrocarbons, fatty acids of the water samples were quantitatively analyzed by Gas Chromatography-Mass Spectrometer(GC-MS). The results showed that the contents of PAHs and fatty acids in water of Qingmuguan karst underground river ranged from 77.3 to 702ng·L -1 and 3302 to 45254 ng·L -1 , respectively. In terms of composition, the PAHs profiles were dominated by (2-3) rings PAHs in water samples, which accounted for more than 90% of the total PAHs contents, while the carbon numbers of fatty acids ranged from C 10 to C 28 , and fatty acids profiles were dominated by saturated straight chain fatty acids, followed by mono-unsaturated fatty acids. In terms of the distribution characteristics, the contents of PAHs had minor difference at each sample point in water of underground river in rainy season. At the entrance, exposed and exits, the contents of fatty acids reduced in turn, moreover the contents of fatty acids were close at the exposed and exits. dry season:at the entrance, exposed and exits, the contents of PAHs in water of underground river decreased firstly and then increased. The contents of fatty acids were close at each sample point in water of underground river. As a whole, the contents of PAHs and fatty acids in water of underground river in rainy season were significantly higher than those in dry season. Source analysis indicated that the PAHs in water of Qingmuguan underground river were mainly originated from the combustion of coal and biomass (wood, crop straw, etc) at the underground river catchment. The fatty acids were mainly originated from aquatic algae (diatoms and green alga, etc), and bacteria, with the contribution of aquatic algae dominated. The water of underground river was suffered the middle to mild pollution by PAHs, and compared with the dry season, the rainy season was more severely polluted.

Water samples in Qingmuguan underground river were collected to determine the concentration of dissolved lipids, and their sources, composition and migration characteristics in underground river were studied. The results were obtained as follows. (1) The average content of various dissolved lipids decreased with increasing distance of migration in Qingmuguan underground river, and the most distinctive was dissolved saturated straight chain fatty acids with its content decreasing by about 81.71%, from the initial 5,704 ng · L⁻¹ to 1,043 ng · L⁻¹. (2) N-alkane could indicate the sources of dissolved organic matter in underground river, but saturated straight chain fatty acid and fatty alcohol had the advantage in indicating algae, bacteria and other microorganisms. (3) With the increasing migration distance of Qingmuguan underground river, the input type of dissolved organic matter in underground river was different, which might be resulted from the heterogeneity of karst surface. (4) In ternary plot of alkane sources, aquatic plants constituted the major contribution of dissolved organic matter in Qingmuguan underground river, followed by higher plant, algae/ bacteria. Unlike higher plants and algae/bacteria, the contribution from aquatic plants decreased with increasing migration distance of underground river. (5) To a certain extent, TAR (alkane) values could reflect the rainfall, and the values of CPI, L/H in saturated straight chain fatty acids might indicate the degradation activities of bacteria.

Six typical surface soil samples were taken in Laolongdong underground river basin, and 20 OCPs were analyzed by gas chromatography equipped with micro-⁶³Ni electron capture detector. The purpose of this study was to investigate the distribution, composition and source of organochlorine pesticides ( OCPs) in the surface soil of Laolongdong underground river basin, and to further evaluate the pollution level. The results showed that 20 OCPs were inordinately detected in the soil samples and the detection rate of 16 OCPs (except for p,p'-DDE, cis-Chlordane, trans-Chlordane, dieldrin) was 100%. Moreover, the CHLs and DDTs were the main contaminants, and there were obvious differences in the concentrations of organochlorine pesticides between different sampling points. The concentration range of total OCPs was 5.57-2,618.57 ng · g⁻¹ with a mean of 467.28 ng · g⁻¹. Compared with other regions both at home and abroad, the concentrations of HCHs and DDTs in the surface soil samples of the studied area were arranged from high to middle levels. The total concentrations of OCPs, HCHs, DDTs and CHLs had a similar variation tendency in spatial distribution, upstream > midstream > downstream, and the concentrations of OCPs in upstream were obviously higher than those in midstream and downstream. Source analysis indicated that the HCHs mainly came from the use of lindane. DDTs in soil came from not only the early residues but also recently illegal use of industrial DDTs and the input of dicofol. In addition, chlordan was mainly from the early residues and atmospheric deposition. Compared with the Environmental Quality Standard for Soils of China and Netherlands, the level of OCPs in Xinli vilage soil was categorized as highly polluted, but the levels of OCPs in Longjing bay, Xia spit, and Zhao courtyard soils were classified as slightly polluted, while the Longjing adjacency and gaozhong temple soils belonged to unpolluted ones.

The water samples were continuously collected at the outlet of Nanshan Laolongdong subterranean river basin, which is located in Chongqing, during the rainfall event in June 2014. Sixteen priority polycyclic aromatic hydrocarbons (PAHs) in water were quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS). The objectives of this study were to reveal the variation characteristics and sources of PAH16 in karst subterranean river during the rainfall event. The results showed that the subterranean river responded promptly to the rainfall, and there were four peaks of the total concentrations of PAH16, two peaks occurred during the flow rise stage, the others were in the maximum flow and flow decline stages. The total concentrations of PAH16 ranged 101-3 624 ng x L(-1), with a mean of 578 ng x L(-1), the total concentrations of 7 carcinogenic PAHs ranged ND-336 ng x L(-1), with a mean of 31.1 ng x L(-1). The PAH compositional profiles were dominated by 2,3-ring compounds, which accounted for 86.17% of the total concentrations of PAH16. The total concentrations of PAH16 were most influenced by the rainfall, through the cleaning of atmospheric pollutants by the rain and the scouring of the surface contaminants by the rainfall runoff. The PAHs in water mainly originated from the incomplete combustion of petroleum products and fossil fuels such as coal, as well as natural digenetic process. Compared to other areas in the world, the concentrations of PAH16 were generally at moderately polluted and heavily polluted levels.

Water samples were collected from the Qinmuguan underground river from July to November in 2013. By gas chromatography-mass spectrometer (GC-MS), dissolved sterols were quantitatively analyzed. The results show that the average variation content of dissolved sterols ranges from 415 to 629 ng x L(-1), with the increasing migration distance of dissolved sterols in underground river, its contents are decreased. Between the inlet and outlet of Qingmuguan underground river, the average variation contents of dissolved sterol are between 724 and 374 ng x L(-1), and the average variation ratios of the content of stigmasterol with cholesterol range from 0.29 to 0.12. In short, their values are decreased accompanied by the increasing migration distance of underground river. The composing component in dissolved sterols varied differently between July to December, and the main component of dissolved sterols is cholesterin, the ratios of the content of dissolved sterols with cholesterin to the total dissolved sterols range from 37.30% to 94.85%. In addition, the ratios of the content of dissolved sterols with coprostanol to cholesterin, coprostanol to cholesterin are below 0.2 respectively, indicating the water quality of underground river is not contaminated by domestic sewage, but with the passage of time water quality tends to deterioration.

Dissolved alkanes and dissolved fatty acids were collected from Qingmuguan underground river in July, October 2013. By gas chromatography-mass spectrometer (GC-MS), alkanes and fatty acids were quantitatively analyzed. The results showed that average contents of alkanes and fatty acids were 1 354 ng.L-1, 24203 ng.L-1 in July, and 667 ng.L-1, 2526 ng.L-1 in October respectively. With the increasing migration distance of dissolved alkanes and dissolved fatty acids in underground river, their contents decreased. Based on the molecular characteristic indices of alkanes, like CPI, OEP, Paq and R, dissolved alkanes were mainly originated from microorganisms in July, and aquatic plants in October. Saturated straight-chain fatty acid had the highest contents in all samples with the dominant peak in C16:0, combined with the characteristics of carbon peak, algae or bacteria might be the dominant source of dissolved fatty acids.

Dissolved alkanes were collected from Dalv spring and Jiangjia spring from July to November, 2013, and were quantitatively analyzed by the gas chromatography-mass spectrometer (GC-MS). The results show that the total content of dissolved alkanes in Dalv spring is 175-3279 ng x L(-1), with a mean value of 1011 ng x L(-1). In Jiangjia spring, the total content of dissolved alkanes is 282-775 ng x L(-1), with a mean value of 527 ng x L(-1). Ratios of the content of alkanes with high carbon number( C25-C32) to the total alkanes vary from 27.89% to 52.92% in Dalv spring, and 23.66% to 49.73% in Jangjia spring. Combined with CPI and OEP the relative contribution to the dissolved alkanes of higher plants are increasing in Dalv spring, however, it is different in Jiangjia spring. In addition, the values of L/H couldn't reflect different organic contributions to the dissolved alkanes, and the values of TAR may relate with rainfall.

Runoff samples were collected from traffic roads, campus, residential road and roof in a typical rain event. Polycyclic aromatic hydrocarbons (PAHs) in both dissolved and particle phases were investigated at impervious surfaces. The PAHs wash-off process at different monitoring sites was analyzed. The scatters of first flush were conducted in a method of fitting power function to quantitatively assess the magnitude of first flush effect (FFE). The sources of PAHs were identified using factor analysis. The results showed that PAHs concentrations in runoff samples varied from 317.21 ng x L(-1) to 10364.3 ng x L(-1) with the maximal and minimal contents of PAHs found on Longwu Road and campus, respectively. The values of event mean concentration ( EMC) varied considerably at different sampling sites. The concentration of washed-off pollutant generally decreased with runoff duration, which showed an obvious attenuation trend. The runoff process indicated the occurrence of FFE at different levels. PAHs mainly came from the incomplete combustion of fossil fuels, oil leakage and coking, and the contribution of each source was different in accordance with various surfaces.

This work aims at preparing oil spill sorbent (TCS, Trichoderma viride-modified corn stalk) through solid-state fermentation of corn stalk by Trichoderma viride. Single-factor experiments, including the effect of modification time, solid-liquid ratio of modification and modification temperature, and adsorption experiments simulating oil spill condition, were carried out. The results indicated that the maximum oil adsorption of TCS, 13.84 g x g(-1), could be obtained under the conditions of 6 days of modification, with a solid-liquid ratio of 1:4 and a modification temperature of 25 degrees C. This oil absorption was 110.33% of that of the raw material (RCS, Raw Corn Stalk). Comparing RCS and TCS by means of Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD), the results separately showed that TCS had rougher surface, lower cellulose content and higher instability, which explains the increase of oil absorption. Also, the component analysis indicated that bio-modification could reduce the contents of celluloses and hemicelluloses from corn stalk. Besides, sorption kinetics and oil retention performance test showed that, TCS, which could reach adsorption equilibrium after 1 h of 80 r x min(-1) oscillating, had fast oil adsorption rate, and it also had good oil retention performance, which could keep 74. 87% of the initial adsorption rate when trickling 10 min after reaching adsorption equilibrium.

Undisturbed soil monolith lysimeter was used to investigate the effectiveness of DCD (dicyandiamide) in reducing N2O emissions in vegetable (Chinese cabbage and pepper) field. Results showed that DCD significantly reduced total N2O emission in vegetable field. Total N2O emissions from the urea treatment without DCD reached 0.215 kg x hm(-2) for Chinese cabbage, and it reduced to 0.109 kg x hm(-2), equivalent to a 49.3% reduction. The total N2O emissions for pepper were much higher compared with those for Chinese cabbage. The total N2O emitted from the urea treatment was 2.32 kg x hm(-2) (without DCD) and it was reduced to 1.14 kg x hm(-2) with DCD application, representing a 50.9% reduction. In the control treatments where no urea was applied, the daily N2O flux was very low and it never exceeded 9 microg x (m2 x h) (-1) for Chinese cabbage and 22 microg x (m2 x h) (-1) for pepper, respectively, but DCD also reduced N2O emissions (33.5% for Chinese cabbage and 33.4% for pepper). In addition, the urea-N emission factor (EF) was 0.15%, 0.99% for Chinese cabbage and pepper without DCD, respectively, and it was reduced to 0.07%, 0.52% when DCD was applied. These results demonstrated the potential of using nitrification inhibitors (DCD) to mitigate N2O emissions in vegetable system.

In the presence of Al-pillared bentonite with good sorption capacity, nanoscale zero-valent iron supported on Al-pillared bentonite (NZVI/Al-PILC) was prepared with NaBH4 and FeSO4 aqueous solution. The structure of NZVI/Al-PILC was characterized by X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET). The effects of pH values and initial chromium (VI) concentrations on its removal rate by NZVI/Al-PILC were investigated, and were compared with those of unsupported nanoscale zero-valent iron (NZVI) containing the same iron mount of NZVI/Al-PILC. The results indicate that in the same experimental condition, the chromium (VI) removal by NZVI/Al-PILC reached 100% after 120 min. The removal is not only much higher than that (63.0%) of the NZVI containing same iron mount, but also superior to the sum of removal (75.4%) by NZVI containing the same iron amount and the Al-pillared bentonite containing the same clay amount with NZVI/Al-PILC.