The atmospheric formaldehyde column concentration data of four provinces in Northwest China from 2005 to 2018 based on ozone monitoring instrument (OMI) were extracted, and their spatio-temporal change and influencing factors were discussed. The results showed that: in time variation, formaldehyde column had increased firstly and then decreased during 14 years, concentration of formaldehyde column in summer and autumn was significantly higher than that in winter and spring, and the average value in winter was slightly higher than spring. In terms of spatial distribution, formaldehyde column increased from west to east and north to south. High value areas were concentrated in Shaanxi, south-eastern of Gansu and south-western of Qinghai low value areas were concentrated in Ningxia, Qinghai and north-western of Gansu. Stability analysis showed that formaldehyde column was distributed in central and eastern parts, and the distribution was obvious. The main factors affected the change of formaldehyde column concentration including natural and human factors. In natural factors, concentration of formaldehyde column was signally affected by topography,wind direction and temperature. In human factors, it was positively correlated with population density, regional GDP, industrial waste gas emission and construction housing completion area. Among them, industrial waste gas emission was the main impact factor. There was a significant correlation between formaldehyde and aerosol particles in atmosphere. This further indicated that the change of formaldehyde concentration was affected by many factors, but aerosol particles, temperature and emission of industrial waste gas were the dominant factor.

A flow tube reactor was used to simulate the reaction of toluene and OH radical in the presence of NO_x.The products formed in gas phase and particle phase under different relative humidity conditions (17.5%, 35%, 50%, 70%) were determined. The yields of detected products and organic carbon (OC) in the gas and particle phases were reported. The present study show that the relative humidity not only affects the ratio of the reaction pathway of toluene and×OH but also the yield and oxidation degree of the product.

Based on the previous research, the single point measured data was used to drive the SNICAR regional physical model, and the microscopic data was combined with the remote sensing macro technology to numerically simulate and invert the snow albedo and SGS. Results showed that the snow albedo increased with the increase of the solar zenith angle, and the impact in the near-infrared region was more obvious. Under different SGS and BC concentrations, the snow albedo decreaseed with the increase of SGS and BC concentration, and the smaller the particles, the smaller the particle size, the more obvious the effect on albedo, and BC was mainly for the visible light band. SNICAR model and MODIS data were used to invert the SGS in northern Xinjiang, the accuracy could reach 0.749, which realized the scale conversion of single-point SGS to planar SGS. Results revealed the continuous change of snow albedo in the presence of aerosol particles in seasonal snow in arid regions, effectively improved the accuracy of snow particle size retrieval in snow. Provided technical support for simulation of radiation stress caused by aerosol particles in snow.

With Aerosol Conditioning System (ACS1000), aethalometer (AE33) and gas chromatography/mass selective detector (GC/MSD), an experimental study on the atmospheric aerosol in Beijing was conducted from July 15 to August 4, 2019. There was a short-term air pollution process on July 27 and a strong precipitation on July 29 during the observation. This pollution process in Beijing was short and the concentrations of the pollutants changed dramatically. A continuously increasing tread of f(RH) was observed in the experiment, and the measurements indicated that the precipitation had a great impact on the f(RH). The average concentration of PM_2.5 on July 27 was (92.54±47.05) μg/m³ with a dramatic variation. The average scattering enhancement factors for f(80%±1%) from July 28 to July 30 were (1.50±0.35), (1.43±0.36) and (1.48±0.25), respectively. Furthermore, the experimental data were used to develop a quantitative model between f(RH) and gf(RH) for estimating the hygroscopic growth factor gf(RH). The result of the f(RH)-gf(RH) relationship model showed a good performance, and its R² could reach to 0.698.

In order to reveal the spatial distribution of ozone (O₃) and its driving factors in Sichuan Basin, the geostatistical methods such as spatial auto-correlation, spatial hot spot detection and geographic detector were used to analyze O₃ concentration data collected form 82 national control environmental monitoring sites in 18 cities. The results showed that there was an overall upward trend (from (79.95±18.82)μg/m³ in 2015 to (88.64±11.67)μg/m³ in 2017) of O₃ concentration in Sichuan Basin. The O₃ concentration reached highest in the midwest of the basin, including Chengdu, Ziyang, Yaan. And the heavy polluted area expanded as the years progressed.A significant annual clustering pattern (spatial positive auto-correlation, Moran's I was greater than 0) of the distribution of O₃ concentration was showed in Sichuan Basin, in which the H-H clustering areas in the Midwest and the L-L clustering areas in the Southeast of the basin. Besides, the variation of the annual clustering areas were nearly accordant with the variation of O₃ concentration, that is, where the O₃ concentration raised (decreased) were transformed into H-H (L-L) clustering areas. The driving force of 20 socio-economic and natural factors to the spatial variation of O₃ concentration was quantitatively analyzed by using geographic detector. It was found that the socio-economic factors provided a stronger drive force, especially the proportion of urban construction land (driving value, q=0.5734) and the population density (q=0.5479). In addition, the annual precipitation (q=0.4592) also had a significant effect on the distribution of O₃ concentration. The detection of interaction based on geographic detector showed that there was a significant interactions on the spatial variation of O₃ concentration, which made the q value of each factor increased by 1.5~2.1times on average. In addition, the average and maximum values of interactive q of each factor both increased year by year. Among the interaction factors that maximized the q value, the population density (7times) and the industrial dust emission (7times) were highest frequency.

Based on the daily OMI Level-2data products from 2008 to 2017, the spatial and temporal distribution characteristics of the Ultraviolet Aerosol Index (UVAI) in Ningxia Hui Autonomous Region were studied, and the correlation analysis and redundancy analysis of its environmental factors were performed. The results showed that the spatial pattern of UVAIwas gradually decreased from the northwest to the southeast of Ningxia Hui Autonomous Region in past decade, and the high UVAI regions were distributed throughout Zhongwei City, and most of Wuzhong City, Yinchuan City, and Shizuishan City. The monthly variation ofUVAI presented a "V" shape in each year. The characteristics of the four seasons were winter > autumn > spring > summer. In 2013, UVAI abruptly changed from a low value to a high, andit reached the highest in 2017. Theil-Sen Median trend analysis and Mann-Kendall test results showed that seasonal variation was no significant decrease in spring, no significant increase in summer, however, it showed a significantor extremely significant increase in autumn and winter. Otherwise, the study analyzed the trends and found that the concentration of absorptive aerosols was increasing year by year in Ningxia Hui Autonomous Region, and UVAI increased in different degrees in the five cities. The stability of the UVAI variation gradually decreased from Zhongwei City to the north and south with a significant difference in height,the coefficient of variation ranged from 0.293 to 0.442. Among the influencing factors, temperature hadthe greatest impact on the survival time of high aerosol air masses, the energy consumption structure, the total industrial value, and the secondary industry (industrial, construction industry) had a important impact on the generation of aerosols, followed by the impact of precipitation. The average wind speed and maximum wind speed showed a significant negative correlation with the residence time of the upper aerosol air mass in Ningxia Hui Autonomous Region.

On-road emission measurements of two typical China III heavy-duty diesel trucks with and without diesel oxidation catalytic converter (DOC) and catalyzed diesel particulate filter (CDPF), have been conducted by using a portable emission measurement system (PEMS). The results indicated that real-world emissions of CO, THC, solid particle number (SPN) and black carbon (BC) from the two retrofittedvehicleswere (1.31±0.37) g/(kW×h), (0.20±0.03) g/(kW×h), (7.13×10¹⁰±5.27×10¹⁰)particle/(kW×h) and (0.69±0.06) mg/(kW×h), respectively. Compared with the original emissions (i.e., DOC+CDPF removed), these emissions were reduced by 52.48%, 55.69%, 99.91% and 99.22%, respectively. From low-speed, medium-speed to high-speed driving conditions, the reduction ratio of CO and THC showed an upward trend, butthere was no significant difference in the emission reduction of SPN and BC under various operating conditions. Retrofitting with DOC+CDPF had no significant reduction effect on NO_x emissions, which were 9.53 to 9.83g/(kW×h), higher than the emission limit. However, the proportions of NO₂ in NO_x were increased, and the elevations got enhanced from low-speed, medium-speed to high-speed driving conditions.

A plate-type wet electrostatic precipitator was designed and built to research the particle capture characteristic under atomization of charged water drop. The effects of electric field intensity, residence time, dust concentration, and liquid flow rate on removal efficiency were acquired. Results showed that particle grade penetration ratio with charged droplets was higher than the dry ESP. As the electric field intensity increased, reduction of penetration ratio and outlet concentration firstly increased and then decreased with the division of 3.5kV/cm, at which the outlet PM_0.5, PM₁ and PM_2.5 decreased by 28.7%, 28.0% and 27.1% respectively. Longer residence time resulted in higher removal efficiency under the same applied voltage, the penetration ratio for PM_0.5, PM₁ and PM_2.5 reduced by 50.2%, 49.3% and 48.5% when the residence time increased from 2.14s to 4.04s at 4kV/cm. Particle collision and agglomeration could be reinforced as the increase of dust concentration, thus the removal efficiency increased correspondingly. While the electron density was insufficient for particle charge, further enhancement of dust density led to decrease of removal efficiency. Improving the water flow rate was benefit for particle charge, agglomeration, and increase of removal efficiency. Compared with the traditional wet electrostatic precipitator (WESP), adoption of charged dropletscould largely reduce the water consumption and keepthe collection efficiency at relatively high level.

Continuous monitoring of atmospheric conventional pollutants in the airport area was carried out at the point adjacent to the runway of Tianjin airport. The Generalized Additive Model (GAM) was applied to identify the impact factors of NO₂ and O₃ between March 2017 and February 2018, and the contribution rate was determined. The selected factors included environmental factors (SO₂, NO, NO₂ and O₃, CO, PM_2.5, PM₁₀ and previous concentration), meteorological factors (wind direction, wind speed, temperature, dew point temperature, correction of sea pressure) and aviation activity factors (takeoff and landing). The results showed that the daily mean of NO₂ was 17.6~123.6 μg/m³. Among them, the number of days exceeding the standard was 38, accounting for about 13%. The daily mean of O₃ was 1.0~276.1 μg/m³, accounting for 26% of the days exceeding the standard. The pollution of O₃ in the airport area was mainly concentrated in summer. Environmental factors, whose contribution ratewas between 56% and 89%, were the main factors affecting the atmospheric environment in the area. As an important regional pollution source, the contribution rate of aviation activities to the change of atmospheric NO₂ and O₃ concentration was more prominent, Which accounts for 20%. The relative contribution of meteorological factors was relatively low. All Adj-R² of GAM were from 0.85 to 0.96, and the screened influence factors could effectively explain the variation of conventional gaseous pollutants.

The pollutants emission rate and spatial location of engines are dynamic during the LTO cycle of civil aircraft. To quantify and analyze the impact accurately, the paper constructed an aircraft LTO emission impact assessment coupling model. The paper was carried out by simulating the LTO flight path of aircrafts, using aerodynamics model, to get performance parameters (real-time fuel flow) of each position within the path. It defined pollutants emission rates of each position, by applying the emission calculating model. Then, it calibrated the Lagrangian puff model for the emission characteristics of the airplane puff, and simulated pollutants dispersion. It collected airborne data of a typical aircraft during its whole LTO cycle, and carried out a real case study, referring to real-time meteorological parameters. The result showed that the average emission rate of NO_x, SO₂, CO, PM and HC were 17.71, 2.21, 1.05, 0.20 and 0.03g/s respectively during the LTO cycle. When the aircraft took-off, the scope of puff dispersion amassed on the runway and were within 300meters laterally and 3000meters longitudinally of it, and the maximum ground-level concentration of NO_x surpassed 100mg/m³. When the aircraft climbed up to the top of mixing layer, finishing the take-off, the pollutants expanded laterally to 1200m, and the ground-level concentration of NO_x, keeping severe, declined to 298.5μg/m³. while the concentrations of other pollutants were relatively lower.

UIO-66 modified thin-film composite membrane for forward osmosis was fabricated by forming polyamide layer via interfacial polymerization. FI-IR, SEM, AFM, XRD, and contact angle have been utilized to characterize UIO-66 and the thin-film nanocomposite membranes (TFN) for forward osmosis.With DI water as feed solution and a 1mol/L NaCl as draw solution,the water flux of TFN0.04 membrane prepared with dispersing 0.04 wt% of UIO-66, reached from 10.28L/(m²·h) to 13.67L/(m²·h)under FO mode and 17.68L/(m²·h) to 20.41L/(m²·h) under PRO mode. Modified composite membrane has improved permeability and better selection performance. Meanwhile, The pollution experiment found that compared with the pure thin film composite membrane, the modified thin film composite membrane has a slower flux decay tendency and less adhesion to contaminant, which indicated that the modified composite membranes is resistant to pollution.

Many studies have shown that one of the important sources of OPEs in the environment is effluent of wastewater treatment plant (WWTP) and the biological treatment units in WWTP can remove some OPEs. In order to optimize the operating conditions of WWTP to make a better removal of macro and micro organic compounds, a suitable laboratory device is necessary. A set of A²O device was designed and installed in the laboratory and 3kinds of representative OPEs were added into the influent. The results show that the removal efficiencies of OPEs in the units of laboratory device were similar tothat in the same units of WWTP. The removal efficiencies of TBEP under both process conditions werehigh, with total removal rate of 84.6% and 83.6% respectively, while the removal efficiencies of TCPP under both conditions were low. In different treatment units, both TCPP in the anaerobic tank under two process conditions could be remove due to the hydrolysis in the anaerobic tank, and the removal rate in the anaerobic tank of laboratory A²O device (57.7%) was higher than that in the WWTP (25.5%). The removal of TBEP mainly occurred in the aerobic tank, and TBEP removal efficiency (67.9%) in secondary sedimentation tank of laboratory A²O device was higher than that in WWTP. Under twoprocess conditions, the aeration intensity of aerobic tank was large and the added tris (1-chloro-2-propyl) phosphate (TCPP) was hard to degrade, leading to the poor removal of TCPP in the aerobic tank. In addition, the sampling quantity of OPEs in A²O device was optimized to ensure the accuracy of the test.

Based on the addition of iron-based bio-carrier, the function of septic tank was strengthened by the related physicochemical and biochemical reactions, achieving the advanced treatment of fecal sewage. The effect of dissolved oxygen (DO) and carbon to nitrogen ratio (C/N) on the removal of pollutants in the fecal sewage was investigated. Under the obtained optimal operation condition, the transformation mechanism of nitrogen was further explored. The results showed that average NH₄⁺-N, TN, COD and TP removals of 90.74%, 85.81%, 92.65% and 95.78% were achieved, respectively, at the influent C/N ratio of 7.3~8.4 and optimal DO of 2.3~2.7mg/L in the aerobic iron-based bio-carriers pool. When reducing the influent C/N ratio from 3.3~4.2, the system could still maintain average NH₄⁺-N, TN, COD and TP removals of 81.16%, 76.62%, 93.87%and 94.75%, respectively. Mechanism analysis indicated that the addition of iron-based bio-carriers markedly strengthened TN removal, COD degradation and TP immobilizationof thedeveloped septic tank. Analysis on nitrogen transformation confirmed that denitrification was enhanced by the internal electrolysis and denitrifying bacteria coupled denitrifying process, which reduced the organicconsumption during denitrification. the developed novel functional septic tank achieved efficient of TN and TP removal from the low-C/N fecal sewage.

This study explored the addition of two inorganic flocculants, polyaluminum chloride (PAC) and polyferric chloride (PFC), to the activated sludge in a SBR system. The influences on the sludge shape, floc size, sedimentation performance, biomass, EPS component, microbial activity and diversity were systematically investigated. The results showed that sludge floc were both more compact and marginalized after addition of these two inorganic flocculants. The floc median particle size respectively increased by 34.78% and 12.90% after addition of PAC and PFC.However,the sludge sedimentation performance and sludge activity deteriorated due to the accumulation of PAC and PFC. It was also found that the addition of inorganic flocculants had reduced the microbial activity and diversity, hence deceased the EPS secreted by microorganisms.

Ti/PbO₂ electrochemical oxidation mechanisms of three typical fluoroquinolone antibiotics (FQNs) in wastewater were studied. The effects of pH, electrolyte and electrolysis time were optimized, and the removal efficiency, degradation kinetics and products of norfloxacin (NOR), Pefloxacin Mesylate (PEF), and ciprofloxacin (CIP) were explored. The results revealed that, after 240minutes, Ti/PbO₂ electrodes could remove more than 97% of FQNs under the given conditions (initial pH 7.8~8.0, [Na₂SO₄]0: 0.04mol/ L). Moreover, the degradation rates were well fit with the first-order kinetic equation. The decrease percentages of UVA₂₅₄ value were larger than 67%. A significant decrease in SUVA values and aromaticity after degradation was also observed. HPLC-MS/MS was used to confirm the degradation intermediates and three possible degradation mechanisms were proposed based on the oxidation products. The intermediates were mainly produced by defluorination,piperazine ring transformation, and quinoline ring transformation.Furthermore, the electrolytic products had a tendency to increase at first and then decrease over time. Some inorganic products, such as F^-, NH₄⁺, and NO₃^- were founded in the wastewater after treatment. Our results indicated that the Ti/PbO₂ electrodes was effective and proved to be a promising method for the pretreatment of fluoroquinolone antibiotics in wastewater.

The present study was envisaged to study the electrocatalytic degradation of Acid Blue 80(AB80) using an electrocatalytic collaborative system (E-Mn²⁺-PDS). The degradation efficiencies of different catalytic systems were compared, and the effect of factors such as Mn²⁺ concentration, PDS concentration, pH value and current density on the degradation efficiency of E-Mn²⁺-PDS collaborative system was explored. In addition, the oxidizing substances, decomposition products of AB80 and its degree of mineralization in the system were investigated, and the mechanism of degradation was elucidated. It was found that the degradation rate of E-Mn²⁺-PDS collaborative system on AB80 reached 99.9% in 45 min. pH was found to significantly affect the E-Mn²⁺-PDS collaborative system. When pH=3, the degradation rate of E-Mn²⁺-PDS reached 99.6%. The oxidizing substances in the E-Mn²⁺-PDS system included SO₄^-×, HO×, and active Mn³⁺. In the E-Mn²⁺-PDS collaborative system, AB80 underwent a series of reactions, which produced 11major decomposition products. Additionally, the mineralization rate of E-Mn²⁺-PDS system was 2.6 times that of the direct electrocatalysis in 6 hours. The degradation mechanism was found to be the production of SO₄^-×by Mn²⁺ and the current from PDS, which subsequently reacted with water to generate HO×,this HO×oxidized the Mn²⁺ to oxidizedactive Mn³⁺ in the current, and the three different oxidizing species degraded the pollutants together.

In this paper, activated carbon (AC) was modified by immersing it in different solutions, including mixed acid solutions, ammonia solutions, KMnO₄ solutions and surfactant solutions, to improve its adsorption efficiency of endocrine disrupting compounds. Changes in the surface chemistry and the porous structure were assessed by specific surface area and porosity analyser, SEM, FT-IR, and Boehm titration. The best modification method of activated carbon was determined by static adsorption experiments, and the adsorption mechanism of modified activated carbon was discussed. The results showed that KMnO₄ modified activated carbon (AC-K) had the best contaminant adsorption performance. The removal rates of DBP, Atrazine and SMZ by AC-K were 94.5%, 93.8% and 95.5%, respectively, and the adsorption process was in accordance with second-order kinetic equation and D-R model. From the calculated results of these models, we found that the adsorption rates of AC-K on the target pollutants were significantly accelerated, and the secondary adsorption rate constant of Atrazine was 1.75 times than that of AC. The theoretical saturated adsorption capacity of DBP, Atrazine and SMZ by AC-K were improved by 42.2%, 629% and 122%, respectively, compared with those before modification. The adsorption mechanism of activated carbon was transformed from physical adsorption into ion exchange adsorption, after modified by KMnO_4.

In this paper, biochar loaded with nano-ZnO (ZnO-BC) was prepared from water hyacinth. The degradation performance of tetracycline hydrochloride (TC) in two systems, one referred to UV/ ZnO-BC system and the other to UV/ ZnO-BC /sodium persulfate (PS), were comparatively studied. The results showed that the degradation efficiency of ZnO-BC / UV system alongside PS was significantly higher than that of ZnO-BC alone, and the efficiency reached 89.48% after 120min. PS could be used as a strong oxidant that could use photogenerated electrons of nano-ZnO to produce SO₄-· and ·OH, achieving synergistic photocatalytic effects. The oxidation process of TC could be divided into two stages: dark adsorption and photocatalysis. The order of influence factors obtained by response surface methodology was PS concentration > UV power > initial pH value > nano-ZnO mass concentration. The quenching test suggested that SO₄-· and ·OH were the main free radicals in the degradation of TC. One part of the oxidizing free radicals were generated in the solution, the others from some kind of oxygen-containing functional groups on the biochar surface and the excitation of nano-ZnO by UV. On this basis, the synergistic mechanism and principle of PS and ZnO-BC during TC degradation were discussed.

In order to reduce the nitrogen concentration in micro-polluted reservoirs, a mixed high efficient aerobic denitrifying flora-A1, dominated by Pseudomonas, was directional enrichment and domestication from the sediments of Lijiahe Reservoir (Xi'an). Shaker experiments showed that the nitrate nitrogen removal ratio of lean nutrient aerobic denitrifying flora A1reached 93.39% at 15h, and the average nitrate removal rate was 0.2073mg/ (L·h). The total nitrogen removal ratio was 52.11% and the average removal rate of total nitrogen was 0.1153mg/(L·h). There was no nitrite accumulation detected. Nitrogen balance analysis showed that about 45% of the initial nitrogen was removed and converted into gas products. Response surface method (RSM) results showed when C/N ratio=9.96, temperature=22.67 ℃, pH=8.01, speed=91r/min, dissolved oxygen=8.55mg/L, the optimum condition of total nitrogen (TN) removal could be obtained.

Impact of dissolved oxygen (DO) on pollutant removal and bacterial community structure was evaluated in a plug-flow activated sludge system. Results show that the bioprocess could still maintain high removal efficiencies of chemical oxygen demand and nitrogen from sewage when DO concentration decreased from 2.0 to 0.3mg/L, however, the nitrogen removal efficiency fluctuated greatly. The functional bacteria Proteobacteria remained dominant (~ 65%) under lower DO conditions, yet the total bacterial community structure changed in the aeration tank. The Nitrosomonas oligotropha-like ammonia-oxidizing bacteria, Nitrobacter winogradskyi spp., and Group1Nitrospira were identified as the major contributor of nitrification under low DO conditions. The quantitative PCR analysis showed that reducing DO concentration from 2.0 to 0.5mg/L enriched the nitrifiers (mainly Nitrospira), thereby ensuring complete nitrification under low DO conditions. The kinetics coefficient analysis also indicated that reducing DO concentration did not significantly affect the nitrifying bacterial growth, but retarded their decay to ensure biomass in the activated sludge system. These results provide positive support for wastewater treatment plants for saving energy by reducing DO concentration in the aeration tank.

The strengthened removal of natural organic matters was an important object for the technology of drink water treatment. The circulating granulation fluidized bed, as a new type, but effective technology for separating solids from liquids, was the characteristic of a high load of treatment and a strong adaptability to different water qualities. Combining this fresh technology with powdered activated carbon (PAC), the strengthened removal effect of organic matters in the water of reservoirs was studied. It was discovered that when the PACl and PAC were using together, and when the dosages of PACl, PAM and PAC were 24mg/L, 1.2mg/L and 30mg/L, the removal rates of the turbidity, UV₂₅₄, COD_Mn and DOC of water input in the fluidized bed system were 96.5%, 72.0%, 71.7% and 61.0% respectively. Through the three-dimensional fluorescence analysis of organic matters during the water inflow and outflow, it was noticed that, in this fluidizedbed system and under the effect of coagulation and granulation, the FI of fulvic acid and humic acid during water outflow were lowered by 40.1% and 43.0% as against the water inflow, after PAC was put in of 30mg/L, the FI of fulvic acid and humic acid during water outflow were lowered by 54.0% and 55.3% as against the water inflow. The molecular weight of the organic matters in the water of reservoirs lay chiefly between < 1kDa and 10~30kDa, accounting for 37.1% and 39.1% of the total weight of organic matters respectively. In the circulating granulation fluidized bed system, the effect of coagulation and granulation was intended to remove the organic matters in range of 10~30kDa, and the organic matters of < 1kDa could be removed comparatively better due to the adsorption by adding PAC.

Dissolved organic matter (DOM) was extracted from rice and wheat straw at different decomposition phases in aquatic systems. The component, structure and photochemical activity of the DOM were characterized by UV-vis absorption spectroscopy, three-dimensional fluorescence spectroscopy and static photochemical reaction methods. Results showed that decomposition process of straw concluded three phases, i.e., physical-leaching, vulnerable and refractory component decomposition, and the vulnerable decomposition component was the main source of the DOM. The aromaticity, humification degree and molecular weight of the straw-derived DOM increased as a function of decomposition time, while the bioavailability of the DOM gradually decreased. The tyrosine-, humic acid- and fulvic acid-like substances of the DOM gradually accumulated during the decomposition period. By the end of decomposition, the contents of the three components in rice and wheat straw-derived DOM increased by 4.2%~14.3% and 5.9%~12.8%, respectively. However, the tryptophan-like substance and soluble microbial secretion were relatively unstable and gradually decomposed. The UV and fluorescence spectral indices SUVA₂₅₄, E2/E3, S_275~295, S_R, BIX and FI were strongly correlated to the photochemically generated HO×, ¹O₂ and triplet-state DOM (r > 0.61, P < 0.05). Therefore, the photochemical activity of the DOM was concurrently dominated by its aromaticity, molecular weight and bioavailability. Based on the results, it is suggested that exploring photochemical activity of bioavailable components and constructing mathematical models for predicting photochemical activity of DOM should be strengthened in the future studies, which is helpful for understanding the ecological significance of straw-derived DOM.

In order to determine the biological leaching mechanism of mixed strains, three biological leaching-experiments, i.e., adding leaching mixed strains + substrates (ferrous ammonium sulfate, sulfur powder), addingsubstrates alone andsulfuric acid alone were conducted to estimate the contribution from direct oxidation(F₁₁), chemical oxidation (F₁₂) and acid leaching (F₁₃). These experiments were tested for the excess activated sludge to evaluate the leaching of Cu and Zn. Results show that for the leaching of Cu, the contribution rates of F₁₁, F₁₂, and F₁₃ were 92.55%, 7.45%, and 0% respectively, indicating that the primary role of the direct mechanism. For the leaching of Zn, the contribution rates of F₁₁, F₁₂, and F₁₃ were 18.86%, 44.35%, 36.79%respectively, indicating the dominate role of an indirect mechanism. This method can determine the biological leaching mechanism of heavy metals under actual environmental conditions, and provide theoretical basis for related research and practical applications.

Pretreatment can not only facilitate the subsequent anaerobic digestion (AD) of excess sludge, but also may decrease the abundance of antibiotic resistance genes (ARGs) and reduce the risk of ARGs spreading during AD. In this study, the impact of different pretreatments on ARGs and live microbial communities in excess sludge was investigated based on propidium monoazide (PMA) treatment. The results showed that the removal of ARGs by thermo-alkaline, thermal hydrolysis, and microwave pretreatments were 3.32logs, 3.13logs, and 2.95logs, respectviely. The ultrasonic wave pretreatment only removed 0.58logs of the ARGs. With the time extension of thermal hydrolysis, the microorganisms was dramatically removed during 1~2hours. The removal of ARGs was 2.42 logs with thermal hydrolysis extended to 4 hours. Proteobacteria was the dominant bacteria in the raw excess sludge. With the pretreatment of microwave and thermal hydrolysis, Firmicutes and Chloroflexi was greatly improved. The correlation analysis showed that sulI and tetC was very similar that significant positive correlated with several families of microorganisms, which indicated various kinds of the potential host bacteria. However, the good removal of sulI and tetC during pretreatment indicated the poor tolerance of their hosts to the pretreatments. No significant positive correlation was found between ermB and microbial communities, and only few families correlated with tetA. Most ARGs carrying bacteria have little resistance with thermo-alkaline, thermal hydrolysis, and microwave pretreatments, and it is necessary to extend the pretreatment time of thermal hydrolysis appropriately to effectively reduce the ARGs in sludge.

This work was to explore the feasibility of drying municipal dewatered sludge by combined cooling and heating methods, and to reveal the influence of the freezing operation on the drying of dewatered sludge at low temperatures. The experimental sludge samples were collected in a municipal wastewater treatment plant after mechanically dewatering. The influence of freezing operation was studied with scanning electron microscopy (SEM) and flow cytometry. In addition, the influence of different freezing temperatures and time on the characteristics of the drying process for the dewatered sludge were also investigated, as well as the effect of combined cooling and heating methods on the dewatered sludge with different moisture contents and cake thickness. It was found that the freezing operation could increase the micropores inside the sludge samples. When the temperature was reduced to -30℃, the death rate of cells exhibited 15.5%, which was 9.7 times higher than that under unfrozen condition. With the drying temperature set at 60℃, as well as freezing temperatures at -10℃, -20℃ and -30℃, respectively, the drying effect was strengthened and the drying rates were improved by 25.0%, 33.3% and 29.2%, correspondingly. Especially, after freezing for 6 hours, the drying rate of the sludge sample reached the highest value, which had the weight of 5g ±0.1g, the cake thickness of 3mm and the diameter of 50mm. It was also found that the decrease in moisture content might weaken the strengthening effect, which was even lost when the content reduced to 45%. The increase of sludge cake thickness might decline the drying rate as well, which exhibited the values of 33.3%, 31.3% and 30.4% at the thickness of 5mm, 10mm and 15mm, respectively. In a word, this work might provide a valuable reference for the development of the sludge drying process using a heat pump with the combined cooling and heating methods.

In order to understand the range of ^239+240Pu and ²⁴⁰Pu/²³⁹Pu that the data from the literature published in 1991 to 2019, spatial distribution and variability of ^239+240Pu and ²⁴⁰Pu/²³⁹Pu in Chinese surface soil were quantitatively analyzed by statistical analysis and mathematical model. The results showed that the atom ratio of ²⁴⁰Pu/²³⁹Pu in Chinese surface soil was concentrated at 0.18(99%), the global fallout was the main source of ^239+240Pu in the surface soil of China;^239+240Pu was at a low radiation level (£1Bq/kg, 94%) in the surface soil, and the ^239+240Pu of Northwest and Northeast China had a high spatial variability. The ^239+240Pu distribution were affected by atmospheric mixing, canopy effect, soil particle size, organic matter and migration (horizontal and vertical migration). At the same time, this study systematically combed out the mathematical model for calculating the spatial variation of ^239+240Pu in surface soil of China, providing an effective method for quantitative assessment of the environmental level of ^239+240Pu.

In order to analyze and compare the remediation effects of the different biochars on crude-oil contaminated soil in eastern Gansu Province of the Loess Plateau, three types of biochars were fabricated from maize straw (JYB), wheat straw (JXB), and apple tree branch (JYB), together with the indigenous plant, Calendula officinalis, were taken as tested plant (J) to do the in situ ecological restoration for four months in the second oil production plant of the Changqing Oil Field Company. The changes of environmental factors, including soil total petroleum hydrocarbons (TPH) degradation rate, plant growth indices, soil physicochemical traits, enzyme activity, and soil microbial community structure were investigated by the conventional methods. The soil TPH degradation rate in the JYB[(59.89±2.23)%] and JGB[(58.17±1.89)%] treatments was relatively higher than that in the JXB and J treatments (P < 0.05). The plant height, plant aboveground and underground dry weight of Calendula officinalis, as well as its rhizospheric soil available N, available P, available K, and activity of soil dehydrogenase and polyphenol oxidase in the JYB, JXB, and JGB treatments were significantly higher than that in other treatments. While compared with JXB treatment, the plant root length, soil catalase and urease activity in JYB and JGB treatments were significantly increase by 23.81%、18.89%, 153.12%、80.13% and 188.66%、117.45%, respectively(P < 0.05). Furthermore, the dominant genera of soil microbial community with capacity of crude-oil degradation in the JYB and JGB treatments, including Sphingomonas, Oleispira, Simiduia, Salinimicrobium, Acinetobacter, Rhodococcus, Alcanivorax, and Nocardia, were significantly higher than that in the JXB and J treatments (P < 0.05). All of the results mentioned above indicated that the soil microbial community structures in the JYB and JGB treatments were different from that of the JXB and J treatments, which could be affected by relatively higher value of soil polyphenol oxidase activity (R²=0.9786, P=0.001), soil dehydrogenase activity (R²=0.9713, P=0.005), soil available N (R²=0.6112, P=0.046), Shannon index (R²=0.7311, P=0.036) and Chao1index (R²=0.6361, P=0.041) of soil microbial community, might be the reason why the soil TPH degradation rate in the JYB and JGB treatments was relatively higher than that of other treatments. Consequently, we proposed that maize straw biochar and apple tree branch would be preferred as the crude-oil contaminated soil remediation conditioner for phytoremediation in eastern Gansu province of loess plateau.

Taking the land reclamation and environment remediation of the tailings pond of Chaihe lead-zinc mine for example, according to the ecological closure principle for the tailings pond, three different soil covering and vegetation measures were selected, including 50cm of soil covering with Amorpha fruticosa L. (measure1), 30cm of soil covering after geotextile covering with Amorpha fruticosa L. (measure 2) and150cm of soil covering with Robinia pseudoacacia and Amorpha fruticosa L. (measure 3). Using the shadow engineering method, alternative cost method, restoration cost method and ecological value method, the benefit estimation modelsof the three measures were constructed to estimate the benefits of underground leaching and pollution diffusion prevention, surface runoff erosion and diffusion prevention, and wind erosion and diffusion prevention. The results showed that the benefits of measure1, measure 2 and measure 3 in the underground leaching and pollution diffusion prevention were 29.7524, 34.4956, 36.0475million yuan per year respectively. The three measures could reduce the losses of the surface covering soil, the sediment deposition of downstream rivers and the heavy metal pollution in different degree; their benefits of surface runoff erosion and pollution prevention were 12.2266, 25.8571 and 25.8675 million yuanper yearrespectively. The three kinds of soil covering and vegetation measures could effectively inhibit the diffusion of heavy metalsunder wind erosion; and their benefits of wind erosion prevention were 12.3545, 12.3545, 12.3786 million yuan per year respectively. Comprehensive benefits of the three kinds of soil covering and vegetation measures in heavy metal pollution prevention were 54.3335, 72.7072, 74.2936 million yuan per year respectively. For the three kinds of soil covering and vegetation measures’ comprehensive benefits, the benefit of underground leaching and pollutants diffusion prevention accounted for the largest proportion. The selection of soil covering measures should be based on the prevention of rainwater infiltration and leaching. Combined with meteorological factors such as rainfall, evaporation and covering soil characteristics, the thickness of covering soil and the necessity of setting up isolation layer should be reasonably determined by considering the reclamation and remediation cost.

Characteristics of cadmium ion (Cd²⁺) adsorption on particulate organic matter (POM) isolated from a typical acid purple paddy soil were investigated by means of scanning electron microscopy-energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FTIR), and the fractionation of Cd²⁺ in POM before and after adsorption. The affinity of Cd²⁺ to POM was much higher than that to the original soil. The adsorption kinetic data could be well described by the pseudo-secondary order equation. The Freundlich equation was better than Langmuir model in describing Cd²⁺ adsorption isotherm of POM, indicating that the adsorption of Cd²⁺ on POM was a heterogeneous multi-molecular layer adsorption. The negative Gibbs free energy (DG^θ), and the positive Entropy (DH^θ) and Enthalpy (DS^θ) illustrated that the adsorption was a spontaneous endothermic process. The value of DH^θand the desorption rate of adsorbed Cd²⁺ indicated that Cd²⁺ was bond to POM primarily through chemical reactions, while to the original soil it did mainly through physical forces. The fractionation showed that the adsorption process increased the percentage of exchangeable Cd²⁺ in the original soil and the percentage of exchangeable and complex forms in POM. The above results together with the analysis of EDS and the FTIR spectra revealed that the mechanisms of Cd²⁺adsorption on POM included complexation of oxygen-containing functional groups, ion exchange, cation-π bonding, precipitation and electrostatic adsorption.

In this study, the concentrations, spatial distribution and ecological risk of organophosphate esters (OPEs) in the riparian soil of Liao River were investigated. The total concentrations of OPEs were ranged from 19.6 to 89.4ng/g, with the mean concentration of 44.2ng/g. Compared with other studies, the OPEs pollution in riparian soil of Liao River was at a low level. The OPEs pollution was low in the upstream and high in the middle and downstream on the whole. Alkyl OPEs and triphenylphosphine oxide (TPPO) were the most abundant OPEs in upstream of Liao River, while only alkyl OPEs were the predominant OPEs in downstream. There was no correlation between the concentrations of OPEs and the content of total organic carbon (TOC) in the riparian soil of Liao River, which is related to the hydrophobic characteristics of OPEs. The hazard quotient of each individual OPE and the total hazard quotient of OPEs were all lower than 1, indicated that the ecological risk caused by OPEs in the riparian soil of Liao River was little.

An indicator system for bird ecological heath assessment of mangrove wetland was developed based on the Analytic hierarchy process, and Futian mangrove wetland of Shenzhen Bay was used as an example to evaluate the bird ecological health of mangrove wetland in Guangdong-Hong Kong-Macao Greater Bay Area. The results show that: the weights of the functional layer indicators of the bird ecological health assessment of mangrove wetland are: Habitat suitability index (0.443) > habitat importance index (0.283) > habitat environmental risk Index (0.181) > bird community health index (0.094). The weights and assignments of the nine bird ecological health indicators are: bird diversity (0.094,4), habitat importance (0.283,3), land degradation (0.147,3), noise (0.074,1), light pollution (0.074,4), building impact (0.148,2), heavy metal pollution (0.089,5), organic pollution exposure (0.056,2) and biological invasion (0.035,4). The health comprehensive index (HCI) of the birds in Futian mangrove wetland was 3, which is generally in a “sub-health” state, indicating that the suitability of current habitat had been deteriorated and there were certain environmental risks. Based on the current ecological status of Shenzhen Bay, some suggestions for bird protection are proposed: establish a bird dynamic monitoring network to promote scientific and efficient bird protection decision-making; strengthen urban noise control and reduce the direct impact of human activities to improve habitat suitability; reinforce the monitor and control of pollutant discharge to reduce environmental risks; and improve the overall ecological health of mangrove wetland birds.

In order to explore the the adsorption mechanism of humin (HM) for heavy metal, lignite was selected as the material for preparing HM and optimized the adsorption conditions. The conditions were optimized by response surface method with Box-Behnken design, whereas quadratic polynomial models of adsorption capacity and adsorption rate of Cd²⁺ on HM could be established. The results showed that the pH, dosage of HM and initial concentration of Cd²⁺ presented the higher effect on Cd²⁺ adsorption of HM. It indicated that the optimum adsorption conditions were obtained at the temperature of 308K, 107.82 min, pH 5.55, dosage of HM 0.05g and Cd²⁺ initial concentration of 95.56mg/L. In addition, the adsorption isotherm could be better fitted by Langmuir models than that by Freundlich. The maximum adsorption capacity (54.20mg/g) of Cd²⁺ on HM was obtained at the temperature of 308K, and the thermo dynamic parameters (DG⁰ < 0, DH⁰ > 0, DS⁰ > 0) indicated that this adsorption was an endothermic and spontaneous process when the entropy of the system increased. Besides, according to SEM-EDS and FTIR, the HM surface exhibited higher specific surface area and porous volume. Moreover, it hosted lots of functional groups, such as carboxyl, hydroxyl. This suggested that the Cd²⁺ adsorption on HM was attributed to the hydrogen bond generated by the oxygen groups and the ion exchange between Cd²⁺ inorganic mineral substance on HM surface. This study could provide theoretical foundation for revealing the adsorption mechanism of HM on heavy metals.

In this study, constitution of microalgal particle size in the adjacent waters of Dachangshan island was investigated in 2018 using the high-throughput sequencing-molecular identification and classification technology, and the estimation error of the classification method based on chlorophyll a was assessed. The result showed that the average estimation error of microalgae with a particle size (< 3μm) assessed using the classification method based on chlorophyll a reached 82%, leading to serious underestimation in the composition of microalgae with small particle size. Base on the molecular identification and classification technology, the average biomass proportion of microalgae with small particle size (< 3μm) was 86% in spring, 52% in summer, and 20% in autumn. Aureococcus anophagefferens with the biomass proportion of 41% was the dominant microalga in spring while Ostreococcus tauri with the biomass proportion of 21% became dominant in summer. Both A. anophagefferens and O. tauri could inhibit the feeding and growth of filter-feeding bivalves, which would pose a potential risk to bivalve farming. Top-down effects of bivalve feeding and environmental factors, such as total nitrogen, total phosphorus, and dissolved silicon, influenced the particle size constitution/characteristic of microalgae in this area.

This paper was conducted in Fuzhou city, which was one of the “furnace cities”.Based on the 2009 and 2018 Landsat TM/OLI imagery and with the support of RS, GIS technology and semi-variogram analysis method, the relationship of urban landscape pattern and the urban heat island effectin city scale, the impact of landscape pattern type on heat island effect in characteristic scale were analysed. The results showed that the calculation results of nine landscape pattern indexes in 2009 and 2018 indicated the fragmentation degree of landscape pattern in Fuzhou central city was increased. The characteristic scales of landscape pattern in 2009 and 2018 were 3,600m and 2,500m respectively, indicating that the landscape pattern of the latter was more abundant. Although the heat island effect in the main urban area had been alleviated, the scope of urban heat island has been gradually expanded, and eight new cities have become the new heat island centres; the heat island severity of different landscape pattern types were pure artificial background pattern > artificial background scattering pattern > finger shape and net shape of the artificial background pattern > finger shape and net shape of the natural background pattern > distribution pattern of the natural background > pure natural background pattern. The purpose of this study is to provide optimization direction for the landscape pattern with heat island cooling effect by refining the scale of landscape pattern research.

As an important region of the Yangtze River Protection Strategy, downstream of Jinsha River plays a vital role as the reserve of fish germplasm resources. Therefore, protection of local aquatic ecosystem has been paid more attentions, particularly in the context of the operation of cascade hydropower stations. In this study, the similarity of macroinvertebrate community in three main tributaries of Jinsha River (i.e., Heishui River, Xixi River and Chishui River) and their relationships with the environmental factors were analyzed. The aim of this study was to explore the possibility of Heishui River as an alternative habitat of the Jinsha River. The results showed that Ephemeroptera, Trichoptera and Diptera were the dominant taxa, while Ephemeroptera was the most abundant taxa in all three rivers. The density, biomass, and diversity indices of macroinvertebrate community in Heishui River and Chishui River were all higher than those in Xixi River. A higher similarity of macroinvertebrate community was found between Heishui River and the upper reach of Chishui River, which dominated by the sensitive taxa of Baetidae. In contrast, its similarity with Xixi River, which is close to Heishui River, was relatively lower. Based on the canonical correspondence analysis, elevation and total nitrogen (TN) were identified as the most significant factors (P < 0.05)influencing the macroinvertebrate community structure, which represented as the regional and local habitat characteristics. Although the upstream of Chishui River was threatened by nitrogen enrichment, it still demonstrated a higher similarity with Heishui River than the rest region. The possible reason is that Chishui and Heishui rivers have similar physical habitats at the head stream reaches. Our findings highlighted the important roles of micro-habitats in structuring the macroinvertebrate community even at a relatively large spatial scale. Considering the higher similarities in terms of community structure, biomass as well as diversity pattern between the Heishui River and the Chishui River, they could be a potential alternative habitat for the ecological function protection in this area.

The thermal degradation of decabromodiphenyl ether (BDE-209) was studied at the temperature range of 400~600℃. The types and contents of its degradation products were determined using GC and GC/MS techniques. The effects of temperature, time, and alkaline- and sulfur-containing compounds on the thermal degradation of BDE-209, as well as the formation of brominated dioxins, were discussed in this study. The results showed that both temperature and time were the two key factors for both the thermal degradation of BDE-209 and the formation of brominated dioxins. When BDE-209 was pyrolyzed at 450℃ for 40minutes, the brominated dioxins were generated to the maximum extent. The types of the products confirmed that alkaline compounds promoted the thermal degradation of BDE-209 by reaction with HBr formed from the BDE-209 debromination, and inhibited the formation of dioxins. Similarly, the sulfur compounds also promoted the degradation of BDE-209 and inhibited the formation of dioxins. However, the detailed inhibition mechanism needs to be further investigated in the future study. There are two kinds of degradation reactions for BDE-209, namely, debromination of phenyl rings and cleavage of ether bond. This research may provide a theoretical basis for the safe disposal of BDE-209-contained products and the reduction of secondary pollution.

The strains of Burkholderia cepacia (NR 113645.1) and Bacillus pumilus (NR 043242.1) were isolated from the mangrove rhizosphere soil of Luoyuan Bay. Their phosphate-decomposing characteristics and dynamic phosphorus-decomposing process were characterized. HPLC results showed that the supernatant of B. cepacia bacteria contained gluconic acid, pyruvate, lactic acid, acetic acid, and succinic acid. The production of these organic acids led to the dissolution of phosphate, resulting in that very little gluconic acid in supernatant and a bad phosphate-dissolving effect of B.pumilus. During the dynamic phosphorus dissolution of B. cepacia, The X-ray diffraction (XRD) characteristic peak intensity of calcium phosphate was dropped and the calcium phosphate particles became smaller or even disappeared with the prolonged treatment time. In contrast, XRD and microscope results showed there were no significant changes in the calcium phosphate's characteristic peak intensity and particle size when the same experiment was performed in B. pumilus. Dissolving phosphate is the key to solving the problem of converting insoluble phosphorus source into bioavailable phosphorus source in compacted soil.

In order to explore the regional differences of the nitrogen-fixing bacteria in lakes of cold-arid areas, the nitrogen-fixing bacteria in the sediments of Nanhai Lake and the interaction relationship between the bacteria and the environmental factors were analyzed using the nitrogen-fixing bacteria specific functional gene nif H. The results demonstated that there existed differences in the composition of the dominant nitrogen-fixing bacterial community among various parts of the Lake, with the dominant bacterial community being mainly composed of 3 phyla (Cyanobacteria, Firmicutes and Proteobacteria) and 10 genera (Cyanobacteria, Chromatium, Clostridium, Anabaena, Rhodospirillum, Anaeromyxobacter, Thiocapsa, Cylindrospermopsis, Rhizobium and Pseudomonas). And Cyanobacteria turned out to be the leading bacteria at the phyla level due to the specific environmental conditions of the cold-arid areas like, the long freezing period and strong ultraviolet radiation. Based on the redundancy analysis, a high level of C/N and TP was shown to be the necessary nutrients for the survival of the nitrogen-fixing bacteria by speeding up the nitrogen-fixing reactions therein, while high levels of TN and NH₃-N, and low pH values could inhibit the growth of nitrogen-fixing bacteria in the surface sediments. To be precise, a high pH value would inhibit the growth of Anabaena, Thiocapsa, Cyanobacteria and Rhodospirillum. In this essay, the potential function of the nitrogen fixation was studied by exploring the distributions of nitrogen-fixing microorganisms in the sediments of cold-arid areas, which could better explain the important role that the nitrogen-fixing microorganisms play in the nitrogen cycle.

Based on field sampling and laboratory experiments, distribution of microbial groups in two kinds of artificial forest ecosystems in the semi-arid region of the Loess Plateau was dynamically monitored. The results showed that there were significant differences in environmental factors between forest and wasteland in Beishan, Lanzhou. The soil water content, organic carbon and total nitrogen of forest land were higher than those of wasteland. Total phosphorus had no significant difference with vegetation type, but had significant difference with seasons. Soil temperature in summer > autumn > spring > winter, soil bulk density was negatively correlated with organic carbon and total nitrogen content. The distribution patterns of soil microbial groups in different vegetation types were as follows: bacteria > actinomycetes > fungi. The total abundance of microbial groups was higher in forest than those of barren land. Regression analysis showed that pH was positively correlated with the abundance of bacteria, actinomycetes and microorganisms (P < 0.05), which was negatively correlated with fungi (P < 0.05). There was a significant negative correlation between soil bulk density and the abundance of fungi (P < 0.05). Soil temperature was positively correlated with bacteria, fungi and total number of microorganisms (P < 0.05). Path analysis showed that pH had the largest direct path to bacteria, bulk density had the largest direct path to fungi, and soil water content had the largest direct path to actinomycetes. The results showed that the soil organic carbon, total nitrogen and total phosphorus in vegetation restoration area were higher than those in the wasteland, which indicated that the number and species of microorganisms were affected by the vegetation restoration, and the afforestation mode of mixed forest was suitable for the vegetation restoration in the north of Lanzhou.

Polyamine-production screening media and ultra performance liquid chromatography (UPLC) were used to isolate polyamine-producing bacteria from Cd- and Pb-pollutedrhizospheresoil ofIpomoea aquatica. The effects of functional strains on the growth, polyamine content, antioxidant enzyme activity and Cd and Pbaccumulation of I.aquatica were studied by hydroponics experiment. Results showed that nine high polyamine-production strains were isolated from the rhizosphere soil of I.aquatica. Among them, srainEnterobacter bugandensisYX6secreted spermine and spermidine, strain Klebsiellaquasivariicola YX8secreted putrescine. The adsorption rates for strains YX6and YX8to Cd and Pb were more than 80% in LB medium solution.Hydroponics experiment showed that strain YX6 and YX8significantly increased the content of polyamines (29.3%~180%) and the activities of superoxide dismutase (18.5%~42.7%) and peroxidase (46.2%~100%) in I.aquatica shoots and roots, and significantly increased the dry weight of shoots (21.2%~40.9%) and roots (43.3%~68.2%), and reduced the Cd (45.8%~69.5%) and Pb (42.5%~63.6%) contents in I.aquatica shoots and roots.Polyamine-production bacteria E. bugandensisYX6and K. quasivaricolaYX8not only improved the biomass and antioxidant enzyme activity of I.aquatica, but also reduced the absorption of Cd and Pb by I.aquatica, which provides bacterial resources for the safe utilization of heavy metals in farmland and the reduction of heavy metals content in vegetables.

The present study investigated the effects of exposure to fluoride on apoptosis of PC12 cells and aimed to clarify the role of Fas/FasL pathway involved in this effect. The results showed that treatment with NaF at 20, 40, 80, 160mg/L for 12, 24, 36, and 48hours enhanced the activity of PC12 cells, respectively. Treatment with all dosages of NaF for 24hours significantly increased the levels of reactive oxygen species (ROS) and apoptosis rate and dose-dependently up-regulated the gene/protein expression levels of Fas, FasL, Caspase8, FADD, and Caspase3, but down-regulated the gene/protein expression levels of Bid (P < 0.05). These results suggest that Fas/FasL apoptotic pathway plays an important role in the apoptosis of PC12 cells induced by fluoride exposure, in which FADD may be an important target molecule of fluoride exposure-induced apoptosis.

In order to study the response of two crops to the microbial community structure of rhizosphere in different growth periods under sulfa veterinary drug stress.The amount of phospholipid fatty acids in soils at different micro-interfaces in rhizosphere was determined by rhizobox training experiments. The changes of microbial community structure in different spatial micro-interfaces of domesticated maize and wheat rhizosphere soil under sulfadiazine stress were studied. The results showed that the high concentration of SD had an inhibitory effect on rhizosphere microbial activity, and microbial biomass at different micro-interfaces in rhizosphere was different. The microbial biomass of the rhizosphere 3mm and root chamber was the largest at the micro-interface of the rhizosphere, and the difference between the two was not significant. Different microorganisms had different sensitivity to rhizosphere effects, and rhizosphere effects of bacteria, Gram-positive bacteria, Gram-negative bacteria, cyanobacteria and sulfate-reducing bacteria were obvious. Under the action of SD stress and root exudates, the microbial community structure of rhizosphere soil changed significantly at different micro-interfaces. In the rhizosphere soil of wheat, the ratio of F/B increased with the increase of SD concentration in soil. Under the high concentration (5mg/kg), the F/B ratio was the largest (0.74), which was significantly different from the control (P < 0.05), indicating that the soil pollution remediation ability was enhanced, the sat/mono ratio was decreased at high concentration, and the microbial community structure was transformed in the direction favorable for SD degradation. The rhizosphere effect was beneficial to SD degradation. Under the action of 1mg/kg SD, the degradation rate in wheat rhizosphere soil was 7.01%, while the degradation rate in non-rhizosphere soil was only 2.49%, and the rhizosphere effect of maize was stronger than wheat.

From the perspective of policy optimization of power industry pricing, the objectives, subsidy rates, and total subsidy funds of two kinds of environmental related feed-in tariffs were examined in this paper. Comparisons in terms of subsidy scale, micro-mechanism, sources of funding, and decision-making mechanism were further discussed. The results showed that, the unadjusted environmental protection price provided stable expectation of rich pollution control fund of thermal power industry, while the reductions of renewable energy pricemotivated technological innovation as well as speculation. As for the micro-mechanism, environmental protection price encouraged the technology innovation of pollution control and reduced the private cost of thermal power industry. However, it also transferred emission reduction costs to the whole society by adding substantial costs. By contrast, the renewable energy price promoted the decrease of social cost of power generation. Although the transmission mechanism of renewable energy subsidy funds was more rigid, some obstacles still emerged, such as low additional levy rate, large fund gap, and incompatibility of policy design. In 2015, the total subsidy funds for environmental protection price and renewable energy price were 76.797 billion yuan (excluding tax) and 42.91billion yuan (supply side),respectively.The total funds of environmental protection price exceeded the subsidy of renewable energy, which further consolidated the cost advantage of thermal power. The subsidy structure restricted the development of renewable energy as inconducive to the cleanliness of power structure.

A CGE model including 7 urban and 5 rural household income groups and 3 labor factors, i.e.agricultural labor, skilled worker and production worker, was constructed to simulate income distribution effects of China’s energy resource tax reform, both on coal, crude oil and natural gas respectively and combined, on urban and rural households under low, actual and high tax rate adjustment settings. Then, the impacts of supplementary measures were simulated. It was indicated that implementing coal or natural gas resource tax reform narrowed the income gap among urban households and promoted fair income distribution, but widened the income gap among rural households and enlarged income distribution unfairness; implementing crude oil resource tax reform narrowed the income gap among both urban and rural households, which promoted fair income distribution; when energy resource tax reform on coal, crude oil and natural gas were implemented simultaneously, income distribution effects were depended on the tax rate combination of them; using energy resource tax revenue to subsidize rural households could narrow the income gap among them, which was beneficial to income distribution fairness.

Taking 2006~2016 city-level data as a sample, combined with the spatial diffusion effect, the paper explored the impact mechanism of smog pollution, and it assessed the governance effect and transmission mechanism of the smog control policies. The study found that: smog pollution in China during the inspection period had a certain time lag, spatial correlation and space-time “warning effect”. In the past, environmental regulation did not contribute to the expected results in smog reduction due to the near-term transfer of polluting industries between regions. The “Air Pollution Prevention and Control Action Plan” had significant effects on the reduction of the smog concentrations. By 2016, the implementation of this policy has significantly reduced PM_2.5 in the three major economic belts by about 7.1%. Among them, the implementation of urban governance in the central and eastern regions has the most significant effect; since the implementation of the policy, environmental protection departments in various regions had achieved short-term effects of smog reduction by restricting production and remediation of heavily polluting enterprises, but the innovation incentive transmission effect on heavily polluting enterprises had not been significant. Therefore, future smog management policies need to focus more on how to establish long-term effects mechanism by stimulating corporate green technology innovation.

The inventory of carbon emissions in the life cycle of photovoltaic industry was analyzed. The carbon emissions from different scenarios for disposal stage were compared. The data for the resource, energy fluxes and environmental emissions were obtained from site investigations, published literature and new technologies development and application. It shows that the carbonemissions of manufacture stage were high, among which the polycrystalline silicon production process's carbon emissions were the most. The carbon emissions of use stage were the lowest, accounting for 3.7% of manufacture stage. Thermal power consumption was the primary factor of carbon emissions, which its carbon emission was accounting for 64.98% of manufacture and use stages. The carbon emissions of disposal stage were highest in landfill treatment followed by dismantling and thermal decomposition. Landfill could increase 0.08% of carbon emissions in manufacture and use stage. In contrast, dismantling and thermal decomposition could reduce 6.03% and 33.59% of carbon emissions more significantly. The results highlighted that the carbon emission of 1kW·h of electricity generation from photovoltaic module with thermal decomposition in disposal stage were significantly lower than these from other research and current electrical power system in China. Development of photovoltaic industry would achieve a win-win situation between environment and energy.

The effect of provincial spatial agglomeration structure on haze pollution and its influencing mechanism were analysed. Haze pollution indicator was measured by the annual mean value of PM_2.5.The development index of primary city, the flatness index of city scale structure, and the provincial polycentric index, which characterized the structure of provincial spatial agglomeration, were constructed using the night light data. Empirical tests based on the static panel data model, IV method and the mediation effect model were performed, the results showed that the development of primary city had intensified the provincial haze pollution; the flattening of city hierarchy structure did not effectively improve haze pollution, but provincial polycentric structure had the effect of driving the haze pollution decrease, and efficiency of energy use was one of the important channels that spatial agglomeration effecting on the haze pollution. Based on the finding, this paper suggested that steady implementation of the provincial polycentric development strategy, and construction of a polycentric atmospheric environment governance structure and governance mechanism.

It is an urgent requirement for achieving high-quality agricultural economic development to promote the decoupling of agricultural wastewater non-point source pollution from agricultural economic growth in the Yangtze River Economic Belt. The decoupling relationship and its evolution trend were analyzed between ammonia emissions, chemical oxygen demand, total phosphorus, and total nitrogen emissions from agricultural wastewater in the Yangtze River Economic Belt from 2011 to 2016. The results showed that: the total decoupling index of non-point source pollution was small and less than 0 in Yangtze River Economic Belt, but the decoupling degree of each pollution source has been deteriorated from 2015 to 2016. In terms of statistical results by province, the decoupling of ammonia emissions and chemical oxygen demand were expansion negative decoupling in agricultural wastewater in Sichuan. The chemical oxygen demand emissions were absolute decoupling in Guizhou, Jiangsu, Jiangxi, Shanghai, Yunnan, and Chongqing. The provinces and cities were mainly located in the middle reaches of the Yangtze River Economic Belt with absolute decoupling of pollutant emissions. There were obvious about heterogeneous spatial boundary spillover effects of Chemical Oxygen Demand, homogeneous spillover effects of total phosphorus and total nitrogen. Moran's I of non-point source pollution emissions from agricultural wastewater increases with distance, but as the geographic distance of the spatial boundary increases, the spatial spillover effect of agricultural wastewater non-point source pollution in the Yangtze River Economic Belt pulses decreases. The long-term impact of ammonia emissions, chemical oxygen demand, total phosphorus and total nitrogen were U-shaped trend on agricultural economic growth. Effects greatest contribution was the chemical oxygen demand, followed by ammonia emissions, total phosphorus and total nitrogen, and the continued positive impact of total phosphorus.