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2022 Vol.42 Issue.12,Published 2022-12-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Ecology
Environmental Impact Assessment and Management
Environmental Toxicology and Health
Carbon Emission Control
Air Pollution Control
5459 The study on the impact of boundary layer schemes on O3 simulations in the Beijing-Tianjin-Hebei region
LU Yan-ting, ZHAO Xiu-juan, TANG Gui-qian, XU Jing, CHEN Dan, AN Xing-qin
Three boundary layer schemes, YSU, MYJ, and ACM2, in the WRF-Chem model were used to simulate O3 during June 2019, a typical pollution month, over Beijing-Tianjin-Hebei and surrounding areas. The spatial-temporal distribution of simulated surface meteorological variables, NO2 and O3 concentrations, and the vertical profiles of temperature, humidity, wind components, and O3 concentrations were compared. The simulations showed favorable performance in the spatial-temporal distributions and the vertical profiles of these meteorological variables in all three schemes, with the best performance of MYJ. All schemes could well simulate the diurnal cycle of planetary boundary layer height (PBLH), with correlation coefficients ranging from 0.58 to 0.69, but with overestimation and underestimation in daytime and nighttime, respectively. The YSU scheme performed best in PBLH simulation. The simulated NO2 concentrations were generally overestimated by three boundary layer schemes, while the O3 simulations were underestimated. The deviations were smaller for daytime simulations and more significant for nighttime. The best simulation was from ACM2, followed by YSU and MYJ. All three schemes gave vertical distributions of O3 but underestimated their concentration. The simulating differences of profiles were more significant in the morning than in the afternoon. Additionally, three sensitivity experiments based on YSU were set up in this paper to compare and analyze the effect of the change of vertical mixing process on the simulation of O3 concentration by adjusting the turbulent diffusion coefficients threshold values (TDCTs) used in the chemistry module, and the simulated changes only reflected the difference of pollution due to the change of vertical mixing process in the boundary layer rather than the change due to the adjustment of the thermodynamic field. The simulation results showed that all three experiments could improve the simulating performance of surface NO2 and O3 at the upper surface of the region. In particular, the most significant improvement was found in the North China Plain, where O3 is significantly underestimated by the original three boundary layer schemes, and the mean bias is reduced by 23.7%. Vertically, the adjustments of TDCT increased the O3 concentration near-surface in the morning and improved the simulation bias, but at the same time increased the negative bias of the underestimated O3 concentration in the upper levels. The sensitivity experiments significantly improved the simulation performance at nighttime but not significantly during the daytime. This study showed the importance of turbulent diffusion coefficients on the vertical mixing of O3. Therefore, improving the parameterization of turbulent diffusion coefficients is necessary for O3 simulations.
2022 Vol. 42 (12): 5459-5471 [Abstract] ( 235 ) [HTML 1KB] [ PDF 3318KB] ( 1295 )
5472 A revised approach to CMAQ near-surface ozone modelling results in Lanzhou-Based on machine learning methods
ZHOU Heng-zuo, CHEN Heng-rui, LIAO Peng, KONG Xiang-rui, PAN Feng, YANG Hong
To better simulate the near-surface ozone concentration in Lanzhou, the XGBoost (eXtreme Gradient Boosting) model and the LSTM (Long and Short-Term Memory) neural network model in the machine learning method were used on the basis of CMAQ (The Community Multiscale Air Quality Modeling System) to establish a revised model of near-surface ozone simulation results, and the combined LSTM-XGBoost model was constructed based on the two methods with the combination of the inverse of error variance weights to further improve the revision effect. In this study, four national monitoring sites in Lanzhou (Lan Lian Hotel, Railway Design Institute, Yuzhong Campus, and Biological Products Institute) were selected, and ambient air quality monitoring data and meteorological data in July and August 2019 were used to revise the near-surface ozone concentrations simulated by CMAQ. Results showed that the CMAQ model could simulate the spatial and temporal distributions of the near-surface ozone concentrations in Lanzhou, but the concentrations was underestimated. Among the revised models mentioned above, the XGBoost combined model revised best. Compared with the simulation results of CMAQ, the correlation of ozone concentration improved from 0.61~0.76 to 0.89~0.95, the correlation of 8h ozone concentration improved from 0.65~0.79 to 0.81~0.88, the ozone RMSE improved from 44.83~70.17μg/m3 to 15.21~26.53μg/m3, 8h ozone RMSE improved from 40.07~67.57μg/m3 to 14.24~28.54μg/m3. This study indicated that it is feasible to revise the model simulation results using machine learning methods to improve the air quality model.
2022 Vol. 42 (12): 5472-5483 [Abstract] ( 340 ) [HTML 1KB] [ PDF 2288KB] ( 908 )
5484 Effects of South Asian High Pressure on regional persistent ozone pollution in Sichuan Basin during summer
KANG Ping, ZHANG Zi-huan, WANG Tian-qi, ZHANG Xiao-ling, LIU Wei, LEI Yu
Based on the monitoring data of ozone (O3) concentration in Sichuan Basin from 2015 to 2020, a database of O3 regional persistent pollution cases was constructed and further spatio-temporally matched with high and low altitude meteorological observation data. The effect of the South Asian High Pressure system (SAH) on the surface meteorological elements and O3 pollution generation in Sichuan Basin during summer was investigated by applied this database. The O3 regional persistent pollution (ORPP) in Sichuan Basin became worse from 2015 to 2018, while the pollution trend remained relatively stable from 2018 to 2020. And ORPP was mainly concentrated in spring and summer season. The situation of O3 pollution was most severe in central-south part of the basin (especially in Chengdu, Chongqing, Luzhou), and the high value area gradually shifted to the north-south direction. (2) The mechanism of ORPP generation was explained based on the influence of SAH (system presence rate, center dispersion and east-west oscillation) on surface meteorological elements:When the mean value of system presence rate was low and the location was eastward, the average temperature, daily temperature difference and sunshine duration were high and the relative humidity was low, which was favorable for O3 generation. When the eastern mode of SAH centers were significantly concentrated, the daily temperature difference and sunshine duration increased dramatically, which was tended to cause abnormally high O3 concentrations; When the western mode of SAH oscillated dramatically, the change of daily temperature difference, sunshine duration and relative humidity could cause large fluctuations in O3 concentrations. (3) Compared the clean period with the polluted period, the system presence rate, center dispersion and east-west oscillation of SAH had a combined effect on the clean period, while the polluted period was mainly influenced by the center dispersion and east-west oscillation. The regional persistent secondary pollution processes (ORPP2) were prone to occur in Sichuan Basin, when the severe oscillation of western mode and the significant accumulation of eastern mode occurred simultaneously.
2022 Vol. 42 (12): 5484-5496 [Abstract] ( 295 ) [HTML 1KB] [ PDF 2170KB] ( 799 )
5497 The characterization and source analysis of atmospheric CO2 in different areas of Shenzhen
SUN Tian-le, HE Dong-yi, LIN Xiao-yu, TANG Meng-xue, CAO Li-ming, JI Jun-ping, GU Tian-fa, HE Ling-yan
This study was monitored CO2 and CO concentrations for one year at two sites (Roadside Station and University Town) in Shenzhen from December 1, 2020 to December 1, 2021.During the observation period, the average atmospheric CO2 concentrations of the University Town and Roadside Station in the Shenzhen were 432x10-6 and 438x10-6, respectively. The atmospheric CO2 concentration at both sites showed the seasonal variation characteristics of high in autumn and winter and low in spring and summer, and diurnal variation characteristics of low in day and high in night. In addition, introducing the net change values of CO2 and CO (ΔCO2 and ΔCO), the ΔCO2/ΔCO values at the University Town and Roadside Station in the Shenzhen ranged from 136.8 to 184.8 and 59.0 to 119.3, respectively, indicating that vehicle emissions contributed significantly to atmospheric CO2 in Shenzhen.
2022 Vol. 42 (12): 5497-5505 [Abstract] ( 311 ) [HTML 1KB] [ PDF 695KB] ( 768 )
5506 The characterization of nocturnal dinitrogen pentoxide pollution in winter of Shenzhen
YUN Long, NIU Ying-bo, LUO Yao, LU Jun-ming, WANG Jun-rui, LIN Chu-xiong, GU Tian-fa, QIU Zhi-cheng, HUANG Xiao-feng, HE Ling-yan
The heterogeneous hydrolysis of N2O5 has a significant impact on nocturnal particulate nitrate formation, yet this process in highly polluted urban areas in winter remain poorly understood. Previous N2O5 observations in the Pearl River Delta are mainly concentrated in summer or warm conditions. At present, there is no report on the observation of N2O5 at night in winter in Shenzhen. Here we presented measurements of gas-phase N2O5 and HNO3 by high-resolution time-of-flight chemical ionization mass spectrometer (ToF-CIMS) during winter in urban ShenZhen, China. In this season, N2O5 showed large day-to-day variations with average mixing ratios of (174.3 ±262.0)×10-12, with the maximum value of 4535.1×10-12. High reactivity of N2O5, with average τ(N2O5)-1 of 8.3×10-2s-1, suggested active nocturnal chemistry and a large nocturnal nitrate formation potential via N2O5 heterogeneous uptake. Coupled with simultaneous measurement of NO, NO2, O3 and pNO3-, the chemical behavior of active nitrogen in winter night of Shenzhen was quantitatively characterized. In addition, the analysis of odd oxygen budget showed that the measured concentrations of O3, NO2, HNO3 and pNO3- account for all of the Ox, the Ox budget closure occurs at a ratio of 1.5 (HNO3+ pNO3-) formed per Ox lost, indicating N2O5 hydrolysis as the mechanism in winter.
2022 Vol. 42 (12): 5506-5513 [Abstract] ( 260 ) [HTML 1KB] [ PDF 1438KB] ( 1236 )
5514 The concentration characteristics and sources of black carbon at the atmospheric background station, Akedala
XIE Xiang, ZHAO Zhu-jun, LU Zhong-qi, TAO Rui, CAI Hai-yang
In this paper, the concentration features and potential sources of black carbon aerosols (BC) at different time scales at Akedala Atmospheric Background Station were studied by utilizing the hourly mass concentration data of BC at Akedala station from 2011 to 2017 and the meteorological data during the same period. Moreover, the backward-trajectory cluster analysis method, the potential source contribution function (PSCF) method as well as the concentration-weight trajectory analysis (CWT) method were also applied. The results show that BC at Akedala Station presented a fluctuating decreasing trend from 2011 to 2017 with a high level of BC cleanliness. The seasonal variation of BC concentration was characterized as high in spring and winter, and low in summer and autumn with a trend of spring (398.85±189.35ng/m3)> winter (389.89±105.94ng/m3) > summer (272.07±90.07ng/m3)> autumn (269.52±68.07ng/m3). Natural factors were the main causes of BC concentration variation. Moreover, the daily variation of BC concentration was characterized as low in the daytime and high in the nighttime, basically showing a single-peaked distribution. The potential sources of BC at Akedala Station varied significantly with the seasons. According to the analyses by employing the backward-trajectory clustering analysis method, WPSCF as well as WCWT, the potential sources of BC in spring concentrated in the northern foot of the Altai Mountain at the border between southern Russia and Xinjiang, those in autumn were in the economic zone of northern Xinjiang, and BC in winter was influenced mainly by foreign emission sources. Therefore, control of BC pollution requires regional environmental cooperation to achieve joint prevention and control, especially to strengthen the monitoring on cross-border pollution sources.
2022 Vol. 42 (12): 5514-5522 [Abstract] ( 182 ) [HTML 1KB] [ PDF 2141KB] ( 585 )
5523 Comparison of carbonaceous profiles of PM2.5 sources within different cities
WANG Jing, ZHAO Xue-yan, YIN Bao-hui, MA Yin-hong, WANG Jian, LIANG Han-dong, YANG Wen
To investigate the characteristics and regional differences of carbonaceous profiles of PM2.5 sources within different cities, filter samples of coal combustion, diesel vehicles emission, gasoline vehicles emission and cooking emission from Shenyang, Shiyan and Urumqi were collected in this study. We analyzed the carbonaceous fractions (OC, EC, OC1, OC2, OC3, OC4, EC1, EC2, EC3, OPCT) based on thermal-optical transmittance method, and established the profiles of carbonaceous fractions of above four sources. The results showed that the mass fractions of total carbon (TC) in PM2.5 from high to low were cooking emission (65.1%±8.4%), diesel vehicles emission (46.2%±9.5%), gasoline vehicles emission (37.7%±3.5%) and coal combustion (17.3%±8.0%). The highest ratio of OC/TC was found in cooking emission, while the highest ratio of EC/TC was found in diesel vehicles emission. The levels of carbonaceous fractions within three cities can be affected by the different types of the same pollution source after subdivision. However, the overall characteristics were that the proportion of OC2 and OC3 in coal combustion were the highest, and the EC2 proportion in diesel vehicle emission was the highest, the proportion of OC2, OC1 and OC3 in the gasoline vehicles emission were the highest and the proportion of OC2 and OC3 in the cooking emission were the highest. The OC/EC ratios ranged from 0.4 to 7.6 for coal combustion, from 0.2 to 5.6 for diesel vehicles emission, from 1.1 to 38.5 for gasoline vehicles emission, and from 6.4 to 170.2 for cooking emission, respectively. The results of coefficient of divergence showed that different sources in the three cities had different profiles on the carbonaceous fractions, while the carbonaceous fractions from the same source type had similar profiles. We combined the carbonaceous fractions of the same sources type within three cities, used the modified pseudo-inverse matrix in the chemical mass balance receptor model. OC2, OC3, OC4, EC1 and OPCT. were the marker species of coal combustion; EC2 was the marker species of diesel vehicle emission; OC1, OC2 and OC3 were the marker species of gasoline vehicle emission; OC2 and OC3 were the marker species of cooking emission. We can notice that the similar carbon profiles and the consistent marker species of the same pollution sources in Shenyang, Shiyan and Urumqi can provide data reference for related researches within other cities in China.
2022 Vol. 42 (12): 5523-5532 [Abstract] ( 179 ) [HTML 1KB] [ PDF 459KB] ( 775 )
5533 Research on the sources of formaldehyde and its precursors during the active period of atmospheric photochemistry in the Pearl River Delta
LIAO Tong, LIN Yu-jun, JI Wen-hao, LIU Yu, WANG Bo-guang
Based on three representative Air Quality Monitoring supersites in the Pearl River Delta (PRD) region (Dongcheng urban station in Dongguan, Lianhuashan urban station in Shenzhen and Huaguoshan rural station in Heshan), we monitored and analyzed spatial-temporal variation characteristics of formaldehyde (HCHO) and its precursor volatile organic compounds (VOCs) during the active period of atmospheric photochemistry from May to October 2021. This study analyzed the sources of HCHO by multiple linear regression, identified its key VOCs precursors and their contributions, and compared the differences in the sources and precursors of HCHO between three sites. There were obvious differences in the volumetric concentrations of HCHO among the three sites, with the highest concentration in Huaguoshan reaching 5.82×10-9. Compared with the historical data, the HCHO concentration in the rural Huaguoshan site was elevated, while the HCHO concentrations in the urban Dongcheng and Lianhuashan sites were decreased. There was a certain correlation between O3 and HCHO concentrations. In September, when the ozone concentration was the highest, the concentration of HCHO was also increased. In addition, the HCHO concentration on ozone exceedance days was significantly higher than those on ozone non-exceedance days. Using the multiple linear regression method, and selecting toluene, isoprene and O3 as source tracers, it was obtained that the secondary sources contributed the most to the HCHO formation, with the proportion ranging from 43.5% to 54.9%. The proportion of secondary sources at the rural site was higher than that of the other two urban sites. Based on the production yields method, the precursors of the secondary formation of HCHO at each site are mainly olefins, of which the largest contribution was from isoprene, followed by ethylene and propylene. In comparison, it was speculated that the decrease in anthropogenic sources of HCHO led to the decrease of HCHO concentrations at urban sites, while the higher contribution of secondary sources led to an increase of HCHO concentration at the rural site. These results suggested that it was necessary to focus on the control of the anthropogenic source of HCHO and its precursors such as isoprene, styrene and ethylene.
2022 Vol. 42 (12): 5533-5541 [Abstract] ( 322 ) [HTML 1KB] [ PDF 718KB] ( 1328 )
5542 Morphological characteristics of microplastics in the atmosphere and dustfall in southern Urumqi
ZHANG Xiao-hui, Dilinuer·Talifu, Mailikezhati·Maihemuti, LIU Hui-bin, AN Ju-qin, CAI Jing-bo, LIU Bo-wen, ZHAO Qi-long
In this paper, the color, composition and morphology of microplastics in atmospheric total suspended particulate matter (TSP) and dustfall samples from southern Urumqi were analyzed by using stereomicroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that microplastics of various shapes such as fibers, fragments and films were present in TSP and dustfall, and the fibrous (81.8% and 86.2%) and fragmented (56.3%~68.4%) microplastics were predominant in TSP and dustfall, respectively. The plastic components in TSP and dustfall were identified by FTIR to be mainly polyethylene, polypropylene and polystyrene. SEM found that the surface of fibrous microplastics was smooth, with a few cracks and a small amount of debris distributed on it. The fragmented microplastics were curled and broken at the edges, with irregular shape and high degree of breakage, and a large amount of particles adhered to the surface. EDS analysis showed that the microplastics were dominated by C and O elements, and also contained Si, Na and Zn. The results can provide basic data support for further understanding of the atmospheric microplastic pollution in Urumqi.
2022 Vol. 42 (12): 5542-5548 [Abstract] ( 244 ) [HTML 1KB] [ PDF 6734KB] ( 559 )
5549 Estimation and temporal and spatial pattern of anthropogenic CH4 emissions in China from 2009 to 2019
CHEN Tian, PAN Jing-hu
340 Chinese cities selected as the objects, the anthropogenic CH4 emissions of China in 2009 and 2019 were calculated, and their spatial and temporal patterns were analyzed based on three primary CH4 emission sources, including agricultural activities, energy activities and waste disposal sectors by bottom-up accounting methods. The total CH4 emission in China was 40.71 Tg in 2009, and 42.89 Tg in 2019. Although total CH4 emission increased, the emission intensity and per capita emissions remained unchanged generally. Among the primary emission sources, agricultural activities, energy activities, and waste disposal produced 24.88 Tg, 12.06 Tg and 3.76 Tg CH4 emissions in 2009 respectively, of which agricultural activities were the main emission sources. In 2019, their emissions were 16.99 Tg, 21.62 Tg and 4.28 Tg respectively, energy activities being the main source of emissions. Among the secondary emission sources, coal mining contributed the most CH4. The proportions of each emission source varied greatly in different cities. Agricultural activities in Huai'an, Yangzhou and Nantong emitted the most CH4, energy activities discharged the most in Jincheng, Datong and Taiyuan, while waste disposal was the main emission in Beijing, Shanghai and Guangzhou. Anthropogenic CH4 emissions in cities had a significant positive spatial correlation. Cities with high emissions-high concentration decreased and the distribution was concentrated. While cities with low emissions-low concentration increased, and the distribution center shifted to the east. Local urban spatial correlation types showed a strong spatial locking effect and migration inertia. There was a large regional difference between CH4 emission intensity and per capita CH4 emission. Theil index of CH4 emission intensity varies widely between regions, while the gap within the regions is relatively small. When it comes to the CH4 emission per capita, both the Theil index among and within the regions are small.
2022 Vol. 42 (12): 5549-5560 [Abstract] ( 359 ) [HTML 1KB] [ PDF 2377KB] ( 869 )
5561 Spatial heterogeneity and influencing factors of dissolved methane in the channel-type reservoir
ZHANG Bo-wen, LIU Jia, NIU Feng-xia, KANG Man-chun, LI Zhe, LI Shi-jian, XIAO Shang-bin
In this study, by connecting the newly fast-response automated gas equilibrator (FaRAGE) to a greenhouse gas analyzer, we investigated dissolved methane concentration (DMC) at the near-surface and its vertical profiles in the water column at a high resolution in channel-type reservoir-Xibeikou Reservoir in December 2021, together with measurements of water methane oxidation rate and sediment methane release rate on individual sampling sites, we preliminarily discussed the spatial heterogeneity and related influencing factors of DMC. The results showed that the DMC at the surface water ranged from 0.02 to 0.42μmol/L, with a mean of 0.11±0.08μmol/L and increased from the end to the head of the reservoir. The spatial heterogeneity of DMC in the water column within the reservoir was mainly attributed to CH4 production in sediment, CH4 consumption in the water column, and the inflow from the river; accordingly, high DMC in the water column of the reservoir tail resulted from the high CH4 production and low CH4 consumption due to shallow water, while low DMC in the water column of the reservoir head was caused by relatively low CH4 production and high CH4 consumption due to deep water; meanwhile, the inflow from the river may be one of the reasons for the vertical stratification of DMC.
2022 Vol. 42 (12): 5561-5569 [Abstract] ( 268 ) [HTML 1KB] [ PDF 733KB] ( 1500 )
5570 Influence of sludge co-combustion on trace element emission characteristics in a coal-fired power plant
ZHENG Cheng-qiang, ZHU Fa-hua, LI Jun-zhuang, LI Xiao-long, DUAN Jiu-xiang, YAN Jun-bo, WANG Xin-pei, CHEN Zhi-yuan, WANG Hong-liang
Sampled by EPA Method 29 and analyzed by Cold Atomic Absorption Spectroscopy and Inductively Coupled Plasma Spectroscopy, the concentrations of trace elements in the raw fuels, flue gas and by-product samples before and after sludge co-combustion in an ultra-low emission coal-fired unit were obtained, with the influence of sludge co-combustion on the emission characteristics of trace elements being investigated. The concentrations of Zn and Cu elements in sludge were high, which was 18.81times and 17.64times than that in the coal samples, respectively. The content of trace elements in the coal fed into the furnace after sludge co-combustion was generally increased. The mass balance rates of trace elements in the whole system, boiler system and air pollution control facilities of the whole process before and after sludge co-combustion were all within the acceptable range. The co-combustion of sludge had no obvious effect on the distribution characteristics of trace elements, and discharging with fly ash was the main emission pathway for trace elements. The proportion of trace elements emitted to the atmosphere through the stack was very small, no more than 0.43%. Except for Hg, the trace elements in the flue gas in the SCR inlet before and after sludge co-combustion mainly existed in the form of particles. The relative enrichment coefficients of trace elements in fly ash and bottom ash did not change significantly after sludge co-combustion. After the coordinated control of the whole-process air pollution control facilities, the emission concentrations of trace elements in the stack outlet before and after sludge co-combustion were 0~12.76μg/m3 and 0~14.97μg/m3, respectively. The emission concentrations of trace elements after sludge co-combustion meet the requirements of the US emission standards for harmful air pollutants from coal-fired generating units, the air pollution emission standards for coal-fired coupled sludge power plants in Shanghai, and the Ministry of Ecology and Environment's domestic waste incineration pollution control standards. The existing air pollution control system in coal-fired power plants had good adaptability to the emission control of trace elements under the condition of 6% sludge co-combustion ratio.
2022 Vol. 42 (12): 5570-5577 [Abstract] ( 198 ) [HTML 1KB] [ PDF 691KB] ( 810 )
5578 Evaluation of the impacts of straw burning ban on air quality based on WRF-CMAQ
DU Ya-bin, ZHAO Hong-mei, ZHANG Xue-lei, XIU Ai-jun
The influence of straw burning ban policy on air quality in Northeast China was quantitatively evaluated by conducting the air quality simulation using WRF-CMAQ mode in different residue burning scenarios based on localized straw burning emission inventory. From 2013 to 2020, the total emissions of open straw burning in Northeast China showed a variation pattern of increasing at first and then decreasing. There are two crop residue burning and emission peaks in a year:before spring plowing (March and April) and after autumn harvesting (October and November). Among the three provinces, Jilin Province achieved the best results in controlling emissions from straw burning in 2019. The atmospheric CO and PM2.5 from straw burning contribute 24.01% and 39.98% to the total concentration in Northeast China during the straw burning peaks in 2017, imposing detrimental effect on local air quality and human health. With the implement of the strict straw burning ban policy, the contribution rate of crop straw burning to atmospheric CO and PM2.5 in the three northeastern provinces in 2019 decreased by 9.58% and 13.95% respectively compared with the same period in 2017, indicating that the straw burning ban policy in 2019 has effectively improved the air quality in Northeast China. If all three provinces in Northeast China implemented same straw burning ban policy as that in the Jilin Province in 2019, the regional air quality would be remarkably improved in the future. The results in this study can provide the technological supports for formulating the policies of regional air pollution prevention and control.
2022 Vol. 42 (12): 5578-5588 [Abstract] ( 392 ) [HTML 1KB] [ PDF 1581KB] ( 1517 )
5589 Deposition and transformation characteristics of SCR by-product ammonium bisulfate on fly ash
LIU Shen, LUO Zi-ying, QING Meng-xia, WANG Zhao-xi, WANG Li-bang, LIAO Yun-long, HE Xiao-ling, LIU Liang, XIANG Jun
The blockage of the air preheater seriously affected the safe and economical operation of coal-fired power plants, which was often caused by the co-deposition of ammonium bisulfate (ABS) and fly ash. By simulating the temperature field in the air preheater, the deposition and transformation characteristics of ABS under the coexistence of fly ash were explored, which can provide guidance for the prevention and control of air preheater blockage. Fly ash had the capturing and adsorbing effects of the ABS generated in the flue gas, which increased the ABS deposition rate and the initial generation temperature. Under the conditions of 100 μL/L SO3 and 50μL/L NH3, the initial deposition temperature of ABS was between 240~270℃. There was no obvious ABS droplet in the high-temperature reaction basket, and the fly ash had an agglomeration phenomenon; a part of small droplets appeared on the wall of the reaction basket in the low-temperature stage, and the fly ash was in the form of large particles. ABS deposition would lead to the accumulation and adhesion of fly ash particles, which were converted to various sulfate salts with higher decomposition temperatures on the fly ash surface. Compared with the sulfate formed by the evolution of sulfuric acid droplets on the fly ash at low temperature, the sulfate formed by the conversion of ABS has a lower relative decomposition temperature.
2022 Vol. 42 (12): 5589-5597 [Abstract] ( 217 ) [HTML 1KB] [ PDF 1112KB] ( 580 )
5598 Research on vehicle travel emission knowledge graph based on vehicle identification data
ZHAO Yong-ming, DING Hui, LIU Yong-hong, WANG Qing-gang
To realize the refined representation and mining of individual vehicle travel and emission behaviour, a vehicle travel emission knowledge graph was established based on multi-dimensional traffic big data such as trajectories, technical parameters, and emission trajectories of all individual vehicles in the central urban area of Xuancheng City. Spatiotemporal correlations among vehicle, road, travel and emission information were intuitively represented by knowledge graph, achieving the fine mining of multi-scale travel characteristics of individual vehicles on different days, different time periods, and different road sections. A private passenger car was cited as an example, its hourly nodes connected to travel nodes on Monday and Wednesday were 7:00, 8:00 and 17:00, and hourly nodes connected to travel on Friday and non-working days were obviously random. The number of road nodes connected to travel on Monday and Wednesday were few and basically same, and the proportions of mileage on Xuanshui Road, Zhaoting North Road and Zhaoting South Road were 63%~68%, while the road nodes connected to travel on Fridays and non-working days were more dispersed. Through the associated retrieval of travel information and emission information nodes, fine identification and traceability analysis of the spatiotemporal characteristics of individual vehicle travel emissions could be realized. The retrieval results of the example vehicle showed that:the daily CO emission of the vehicle on Monday was 1.2g, which was 2.5times that of Saturday. During the morning peak hour (7:00), when the vehicle travelled on the busy road section, with the low level of vehicle speed, its emission intensity was relatively high.
2022 Vol. 42 (12): 5598-5609 [Abstract] ( 233 ) [HTML 1KB] [ PDF 4850KB] ( 735 )
5610 Evaluation method and application in influences of meteorological element on urban air quality: taking PM2.5 as an example
ZHAO Yu-xi, REN Jia-hao, CHEN Yi-zhen, ZHANG Xin-min, ZHANG Kai, YANG Xin, HE You-jiang
Based on the urban scale air quality model and the advection diffusion theory, this research classified the meteorological elements, then studied the correlation between the air quality and the emission source intensity corresponding to various meteorological conditions, and finally established an assessment method of the impact of meteorological element changes on urban air quality. The method considered the basic meteorological elements including wind (wind speed and direction), cloud cover, solar radiation intensity, atmospheric stability, mixing layer height and so on. The method can evaluate the improvement of air quality caused by long-term meteorological changes quantitatively and effectively. A case study was carried out for Hebi in which the PM2.5 concentration decreased by 7.2μg/m3 in 2021 compared with that in 2020. The calculation result showed that the change of meteorological elements and emission reduction were decreased by 0.4μg/m3 and 6.8μg/m3 which accounted for 5.6% and 94.4%, respectively. The results indicated a leading role of the human efforts on the improvement of the air quality. At the same time, the calculation results showed that concentration of PM2.5 decreased in all of summer, autumn and winter due to the effective prevention and control of air pollution. The most significant effect of human efforts was found in winter. The concentration of PM2.5 decreased by 27.8μg/m3 in winter and the contribution of human efforts was 16.8μg/m3.
2022 Vol. 42 (12): 5610-5616 [Abstract] ( 311 ) [HTML 1KB] [ PDF 472KB] ( 1171 )
5617 Evaluation of the linear relationship validity between two beta attenuation monitors with different configurations
WU Juan, XU Ke-xin, CHI Ying, ZHOU Gang, WANG Wei
In order to evaluate the accuracy of BAM (Beta Attenuation Monitor) with simultaneous cone-sampler, two types of configuration instruments are compared with the long-term ambient air monitoring of inhalable particles (PM10) and fine particles (PM2.5), by using the BAM with step-by-step sampler as the reference method. According to EN 16450, this work evaluates the validity of the linear relationship of the data, establishes a modified linear equation, and derives the uncertainty evaluation formula between methods. The results demonstrate the effective linear relationship between the measuring results of BAM simultaneous cone-sampler and step-by-step sampler. After the concentration slope and concentration intercept are corrected by the built-in correction parameters, the slope, intercept and correlation coefficient (between reference method) of PM10 and PM2.5 meet the requirements of EPA-CFR-40-part53, even in case of relatively large concentration range (0~250μg/m3) and adequate data sets (n>100).
2022 Vol. 42 (12): 5617-5625 [Abstract] ( 212 ) [HTML 1KB] [ PDF 1140KB] ( 786 )
5626 Pollution characteristics of antibiotics resistance associated with bioaerosols from a wastewater treatment plant
YANG Tang, HUI Xiao-liang, WANG Zhen-xing, HE Yu-xin, ZHOU Xiao-lin
In order to explore the pollution characteristics of antibiotic resistance genes (ARGs) associated with bioaerosols from a wastewater treatment plant in Jinan, bioaerosol within and around this plant, and wastewater or sludge, were analyzed using shotgun metagenome sequencing. Compared to bioaerosols from upwind, that from this plant and downwind were characterized with more subtype number and higher total abundance of ARGs. Significant difference (47.57%) for the compositions of ARGs in bioaerosols, was found between upwind and this plant. The dissimilarity of ARGs in bioaerosols was not significant between downwind and this plant, and the difference decreased to 33.98%. Ambient air and wastewater/sludge were both the important source for ARGs in bioaerosols from this plant, with the total source contribution higher than 63.92%. A total of 43subtypes (8types) of ARGs were easily aerosolized in bioaerosols from at least one of the treatment units. These results could provide the theoretical basis for the risk assessment and control of antibiotic resistant contamination in wastewater treatment plants.
2022 Vol. 42 (12): 5626-5632 [Abstract] ( 297 ) [HTML 1KB] [ PDF 654KB] ( 794 )
Water Pollution Control
5633 Enhanced nitrogen and phosphorus removal and microbial analysis of BioDopp process in pilot scale
PAN Jian-tong, YU Cheng, WANG Kai-jun, LIU Fang, YANG Ping
In order to demonstrate the feasibility of simultaneously upgrading and capacity expanding of existing municipal sewage treatment plants, taking a low C/N domestic sewage in Beijing as the treatment object, a pilot test system was constructed using IFAS combined with micro oxygen A/O technology based on BioDopp process. The removal efficiency of organic matter, nitrogen and phosphorus, and the characteristics of microbial community were investigated, and the economic benefits were calculated as well. The results show that the startup strategy of increasing the load by gradually increasing the treated water volume is feasible in view of the low pollutant concentration of the sewage. After only 8days of startup, the operation became stable and the effluent COD, NH3-N, TN and TP concentration reached 18.9, 0.4, 8.3 and 0.7mg/L respectively. The results of high-throughput sequencing showed that the tested process enhanced the enrichment of functional bacteria, especially denitrifying phosphorus accumulating bacteria, and its total relative abundance reached 7.6%, which was 23.6times of that of the activated sludge inoculated. The HRT of the pilot system is 16.6h, which is only 61.0% of the original process (HRT~27.2h) of the sewage treatment plant. It can be seen that this process has significant advantages in land saving, high biological phosphorus removal efficiency, saving reagent cost, and greatly reducing the energy consumption of aeration and reflux by micro oxygen controlling and air lift reflux. Consequently, BioDopp process can be used for the construction of compact sewage treatment plant, which is an efficient energy-saving and carbon reduction tool for sewage treatment plant.
2022 Vol. 42 (12): 5633-5642 [Abstract] ( 224 ) [HTML 1KB] [ PDF 523KB] ( 1286 )
5643 Research on dyeing wastewater treatment with an integrated nanoscale zero-valent iron and biology technology
LIU Jing, LIU Ai-rong, ZHANG Wei-xian
A coupling system consisting of nano zero valent iron and membrane bioreactor (nZVI-bio system) was constructed to explore the feasibility and controllability of a continuous flow reactor for the treatment of Congo red (CR) wastewater. Since nZVI pretreatment converts CR macromolecules into small molecules, the biodegradability index denoted by BOD5/COD increased from 0.04 to 0.69 and toxicity reduced from 90.25% to 30.57% compared to the initial CR wastewater, which provides good environmental conditions for biological units. During the continuous operation of the coupling system, CR removal efficiency reached 99% and COD was reduced from 167mg/L to 50mg/L (nZVI pretreatment process at an initial concentration of 500mg/L). However, the color removal efficiency was just 30%~70% and COD was reduced to 116mg/L for a conventional biotreatment system, and the fluctuation is large. The results demonstrated that the nZVI-bio system provides new technical support for deep treatment of refractory organic dyes.
2022 Vol. 42 (12): 5643-5649 [Abstract] ( 195 ) [HTML 1KB] [ PDF 857KB] ( 691 )
5650 Characterization of dissolved organic matter changes during electrolysis of biochemical effluent in printing and dyeing
ZHENG Rui-hao, HUANG Yan, LIU Zi-feng, WANG Jia-de
Fluorescence excitation emission matrix (EEM), combined with ultraviolet-visible absorption spectroscopy (UV-vis), infrared spectroscopy (IR) and gas chromatography-mass spectrometry (GC-MS), were employed to identify the structure and composition of dissolved organic matter (DOM) from the electrolysis process of printing and dyeing biochemical effluent, to reveal the changes in macroscopic water quality indicators COD and BOD. The three-dimensional fluorescence spectroscopy PARAFAC analysis showed that there were three significant fluorescence peaks of tyrosine (C1), tryptophan (C2) and humic acid (YC3) in printing and dyeing biochemical effluent. At a current density of 15mA/cm2, after a certain period of electrolysis (e.g. 30min), the original fluorescence intensity began to gradually weaken, the maximum fluorescence intensity (Fmax) of C1 and C2 fractions remained the same, and DC3 tryptophan component appeared and reduced Fmax. The B/C ratio of the wastewater increased from 0.27 to 0.42, and the C=C, C=O, C-N and C-O-C structures of the printing and dyeing biochemical tailwater DOM were degraded and the corresponding organic compounds such as olefins, ketones, amines, alcohols, benzenes, halogenated hydrocarbons and esters in the raw water were gradually degraded into small molecule organic acids, alkyl esters, alkanes and other by-products, which is the essential reason for the transformation of fluorophores and the improvement of biochemical properties. The three-dimensional fluorescence visualizes the characteristic spectra of the DOM composition of the electrolysis process, which supports the scientific evaluation of the electrolysis technology and the subsequent traceability of the printing and dyeing biochemical effluent.
2022 Vol. 42 (12): 5650-5657 [Abstract] ( 237 ) [HTML 1KB] [ PDF 642KB] ( 993 )
5658 Removal performance and mechanism of dithiocarboxyl hydroxymethy-polyacrylamide for Cr(VI) in aqueous solution
ZHOU Ya-qi, WANG Gang, ZHANG Hang, MA Yu
The performance of dithiocarboxyl hydroxymethy-polyacrylamide (DTMPAM) in the treatment of Cr(VI)-containing wastewater was investigated with the influences of some parameters, such as DTMPAM dosage, pH value, initial concentration of Cr(VI), and coexisting turbidity, inorganic and organic substances. The results showed that DTMPAM had a good removal efficiency on Cr(VI) in water samples with different initial concentrations of Cr(VI) under acidic conditions, and the removal rate of Cr(VI) increased with the decrease of initial pH in the system. At pH value 3.0, the highest removal rates of Cr(VI) in water samples reached 94.78%, 96.52%, 96.53% and 97.49% at the initial Cr(VI) concentrations of 5, 15, 25 and 50mg/L, respectively. The coexisting turbidity had an inhibitory effect on the removal of Cr(VI) by DTMPAM. At the low DTMPAM dosage, the coexisting inorganic cations (K+, Na+, Ca2+ and Mg2+), the coexisting inorganic anions (SO42-, NO3- and Cl-), as well as the coexisting organic substances (sodium citrate, sodium acetate, trichloroacetic acid and aminoacetic acid) had a certain inhibitory effect on the removal of Cr(VI) by DTMPAM, while at the high DTMPAM dosage, the presence of these coexisting substances exhibited a little promotion for the removal of Cr(VI). The presence of inorganic cations, such as Fe3+, Ni2+ and Ba2+, had a significant inhibitory effect on the removal of Cr(VI) by DTMPAM, and Ba2+ had the most significant inhibitory effect among these ions. Infrared spectroscopy and energy spectrum analysis showed that the dithiocarboxyl groups on the molecular chain of DTMPAM could reduce Cr(VI) to Cr(III) in the water samples, and then Cr(III) could further chelated with the dithiocarboxyl groups and amine groups on the molecular chain of DTMPAM to form flocs.
2022 Vol. 42 (12): 5658-5667 [Abstract] ( 207 ) [HTML 1KB] [ PDF 714KB] ( 1065 )
5668 Performance and mechanism of Cu-Mn-MRBC in the removal of ENR, STZ and TCH antibiotics from water
DONG Ying-hong, LI Hong-yan, CUI Jian-guo, FENG Kun, LI Shang-ming, WANG Fang
This study aimed to investigate the mechanism of action of multiple antibiotic pollutants coexisting in water bodies. In this work, MR biochar (MRBC) was obtained through carbonization using waste bacterial residue (MR) as raw material, and Cu-Mn-MRBC was synthesized through the composite modification of both copper and manganese. The materials were characterized and analyzed by SEM, BET, XRD, FTIR, zeta potential, and EA. Furthermore, the adsorption performance of three antibiotics of ENR, STZ and TCH in single and mixed solutions was studied as well. The results show that comparing with single solution, the emergence of competitive adsorption in mixed solutions increases the selective depletion of oxygen-containing functional groups. Moreover, it promotes the adsorption of TCH with the removal rate of 96.50% in the mixed solution, but inhibits STZ more than ENR, with the removal rates in the mixed solution of 39.38% and 46.13%, respectively. Absorption process in the system decreased the pH dependence. The presence of coexisting cations affects the competitive adsorption capacity of antibiotics. Pseudo-second-order kinetic and Freundlich isotherm models can better describe the adsorption process of Cu-Mn-MRBC. The adsorption is mainly the results of electrostatic interaction, π-π interaction, hydrogen bonding, and surface complexation.
2022 Vol. 42 (12): 5668-5678 [Abstract] ( 211 ) [HTML 1KB] [ PDF 1062KB] ( 1313 )
5679 Effects of pH, sulfate and temperature on chromium release from steel pipe scales
LIU Jing, TIAN Yi-mei, LIU Yun-hui, CHU Xian-xian, LIU Ran, SHAN Jin-lin
The scales of steel pipes in water distribution systems were researched by dividing them into a surface layer, a shell-like layer, and a porous core layer inward. We characterized and analyzed the three layers before and after the adsorption of Cr(VI) using SEM, BET, XRD, XPS, and Tessier sequential extraction and investigated the impact of pH, SO42- concentrations and temperatures on the Cr release from each layer. Results showed that α-FeOOH was the primary component in all layers, and the adsorption capacity in the surface layer, porous core layer, and shell-like layer decreased in order. Iron scales existed mainly in Fe(III) and Fe(II) with certain reducibility. Cr(VI) could physically and chemically adsorb on the corrosion scales, mainly in Fe-Mn oxides. The amount of Cr accumulated on the surface layer was the largest. Low pH, high SO42- concentration, and high temperature promoted the Cr release. Specifically, the Cr release concentration from the surface layer was 2.76 times under strong acidic conditions than under neutral conditions, the one from all layers was increased by 0.1~0.4 times with the increase of SO42- concentration, and the one from the surface layer was increased by 26.74% with temperature increased by 20℃.
2022 Vol. 42 (12): 5679-5686 [Abstract] ( 191 ) [HTML 1KB] [ PDF 1061KB] ( 783 )
5687 Effect of long-term low temperature on nitrogen removal and microbial community of flocculent-granular coupling CANON
LI Bo-lin, XIA Kai, JIANG Yu-qing, WANG Jing, ZHAO Wan-qing, HE Xiao-man
The effects of long-term low temperature on nitrogen removal efficiency and microbial community structure of CANON system with equal sludge concentration ratio of flocculent-granular(1:1~1:1.5) in SBR reactor were studied in this study. The results showed that after long-term operation at low temperature(10℃) followed by recovery from low temperature(10→30℃), the removal efficiencies of NH4+-N、TN and NRR in equal proportion sludge CANON system were positively correlated with temperature, and reached 72.4%, 63.0% and 0.094kgN/(m3·d), respectively, after 30days of operation at 30℃. The activities of AOB and AAOB showed positive correlation with temperature, and reached 0.025 and 0.049gN/(gVSS·d) after recovery from low temperature, about 83.3% and 79.1% of those before cooling, respectively. NOB remained at a low level (0.001gN/(gVSS·d)). The results of high-throughput sequencing showed that long-term low-temperature had no effect on the dominant taxa at phylum level. The dominant phyla of granular and flocculent sludge after rewarming were Ignavibacterium and Proteobacteria respectively. After recovery, the relative abundances of functional bacteria Candidatus brocadia and Candidatus kuenenia (AAOB) in granular sludge were 6.017%, 2.623% respectively, and their relative abundances in flocculent sludge were 3.018% and 0.674% respectively. While Nitrosomonas (AOB) mainly distributed in flocculent sludge, and its relative abundance after recovery was 2.50%. The relative abundances of three functional bacteria were higher than the level before cooling. The equal proportion flocculent-granular sludge CANON system can effectively resist long-term low temperature.
2022 Vol. 42 (12): 5687-5694 [Abstract] ( 204 ) [HTML 1KB] [ PDF 470KB] ( 628 )
5695 Effect of pyrolysis temperature for biochar on improving nitrogen removal efficiency of Anammox
FU Jing-wei, JIA Zi-wen, YANG Xiao-huan, HE Yi-fei, LI Qian
In order to explore the alleviating effect of biochar on nitrate accumulation in anammox process, the effect of biochar at different pyrolysis temperatures (300, 500 and 700℃) on nitrogen removal performance of anammox system was investigated. The results showed that the total nitrogen removal rate was increased by 14.6%, 7.1% and 3.3%, respectively, after the addition of 300, 500 and 700℃ biochar compared with the control group. The main reason was that biochar promoted the reduction of nitrate as an electronic mediator, and the reduction product continued to participate in the anammox reaction to further reduced the residual ammonia nitrogen by 11.2%, 9.1% and 5.8%. The surface of biochar at 300℃ was rich in electron-losing groups such as phenols, aldehydes and ketones, and its electron-donating capacity was 2.64mmol e-/g, which was higher than 500℃ (1.92mmol e-/g) and 700℃ (1.32mmol e-/g), so the electron transfer was better strengthened. Microbial community and functional protein analysis showed that the abundance of Ca.Kuenenia, Pseudomonas and Thauera were enhanced by the addition of biochar, which was beneficial to the enrichment of Anammox and denitrifying bacteria. Meanwhile, biochar enhanced nitrogen metabolism during denitrification by promoting the expression of NapA (EC:1.9.6.1) and NarG (EC:1.7.5.1) functional genes.
2022 Vol. 42 (12): 5695-5702 [Abstract] ( 229 ) [HTML 1KB] [ PDF 1211KB] ( 803 )
5703 Effects of the combination of two typical antibiotics on denitrification process in groundwater
LI Wei, HE Jiang-tao, DENG Lu
Ciprofloxacin (CIP) and lomefloxacin (LOM) were selected as typical fluoroquinolone antibiotics, sodium acetate was used as the carbon source, and batch experiments were carried out to explore the effects of CIP or/and LOM on denitrification process. Then the influencing mechanisms were investigated by measuring the changes of indicators, such as the number and activity of denitrifying bacteria and the denitrifying enzyme activity. The results showed that compared with the blank system, LOM (100μg/L) group, CIP (100μg/L) group and LOM (50μg/L)+CIP(50μg/L) group had inhibitory effects on degradation both NO3--N and NO2--N. The inhibition rates followed an order of LOM + CIP > CIP > LOM. Antibiotic exposure could inhibit the quantity and activity of microorganisms and the activity of key denitrifying enzymes to varying degrees. The NO3--N degradation was affected by the activity of denitrifying bacteria and the activity of nitrate reductase (NaR), while the NO2--N degradation was mainly affected by the activity of nitrite reductase (NiR). The results of the combined effects of antibiotics showed that the inhibition rates of LOM + CIP group in NO3--N and NO2--N degradation stages were greater than those of single-antibiotic groups, indicating the synergistic inhibition of LOM and CIP; the synergistic inhibition of two typical antibiotics on the activities of key denitrifying enzymes was also observed; however, the inhibition of the combined antibiotics group on the quantity and activity of microorganisms indicated the antagonistic effects. The effects of different antibiotics on denitrification effects were different. LOM mainly affected on the NO3--N degradation stage, while the CIP or LOM+CIP showed similar inhibition effects on both stages of NO3--N degradation and NO2--N degradation.
2022 Vol. 42 (12): 5703-5712 [Abstract] ( 227 ) [HTML 1KB] [ PDF 623KB] ( 1161 )
5713 Study on removal of heavy metal ions by mg (OH)2@fly ash composite
WANG Zhi-xue, WANG Cai-li, WANG Bin, YAO Guo-xin, QIU Ying, YANG Run-quan, WANG Hui-fa
Nano-magnesium hydroxide@fly ash composite with core-shell structure was prepared with non-uniform nucleation method taking fly ash as the carrier, MgCl2 and NaOH as reaction coating agents according to the idea of "particle design" and its adsorption properties of Cu(II), Ni(II) and Pb(II) in wastewater were studied. The composite powders before and after coating were characterized by scanning electron microscopy (SEM), energy dispersive (EDS), specific surface area analyzer (BET), X-ray diffraction (XRD) and infrared spectroscopy (FTIR). The results show that the surface of the composite powder is uniformly coated with a large amount of nano-magnesium hydroxide and a small amount of hydrated magnesium carbonate, the specific surface area increased to more than 30 times of the original (fly ash 1.79 m2/g), the average pore size increased from 11 nm to 14.7 nm, and the average pore width increased from 12.8 nm to 15.4nm, respectively. Si-O-C-O-Mg and Si-O-Mg-OH are formed between Si-O-Si, Si-O-C and magnesium hydroxide on the surface of fly ash. The removal efficiency of heavy metals by the composite powder is significantly higher than that of fly ash, and the unit saturated adsorption capacity reaches 216.30, 160.96 and 116.50 mg/g. According to Zeta potential, FTIR and simulation equations, the adsorption mechanism of heavy metal ions by composite powder was analyzed. The results show that the composite adsorbs heavy metal ions through precipitation reaction, electrostatic attraction and ion exchange, etc. The adsorption process isotherm, the kinetics and the thermodynamics conform to the Langmuir isotherm model, intraparticle diffusion model and spontaneous endothermic reaction, reapectively. The desorption experiment indicates that the composite powder has a good regeneration performance in the adsorption process.
2022 Vol. 42 (12): 5713-5724 [Abstract] ( 217 ) [HTML 1KB] [ PDF 2117KB] ( 700 )
Solid Waste
5725 Purification of phosphorus in the incinerated sewage sludge ashleachate by layered double hydroxides
ZHANG Xiao-tong, ZHANG Hua, Lü Fan, HE Pin-jing
Phosphorus is an essential and limited resource. Incinerated sewage sludge ash (ISSA), which is phosphorus-enriched, shows a valuable potential for phosphorus recovery. Wet chemical method can effectively leach phosphorus from ISSA, but the major metals and heavy metals are leached at the same time, which influence the subsequent phosphorus recovery. In this study, Mg-Fe layered double hydroxides (LDH) is used to selectively adsorb and desorb phosphate. The phosphorus adsorption effects of uncalcined (LDHu) and calcined LDH (LDHc) as well as the mechanism of phosphorus adsorption and desorption were investigated. At high phosphorus concentrations (>1000mg/L), the phosphorus adsorption capacity of the LDHu was higher than that of the LDHc. The LDHu has a typical double layered structure. Phosphorus adsorption and desorption was achieved mainly by the phosphate precipitation-dissolution, electrostatic adsorption-repulsion, ligand interaction and ion exchange. After calcination, LDHc lost the layered structure, and was transformed into double metal oxide. There was no significant anion exchange process for the calcined LDH during adsorption and desorption. After LDHu or LDHc adsorption and alkaline desorption, the ISSA leachate could achieve good phosphorus purification effects, with the relative phosphorus purity increased from 36% to 77% and 69%, as well as a phosphorus recovery of 84% and 57%, respectively. The purified ISSA leachate is suitable for the subsequent valorization of high-value phosphorus-containing product.
2022 Vol. 42 (12): 5725-5733 [Abstract] ( 220 ) [HTML 1KB] [ PDF 1792KB] ( 768 )
5734 Mine land ecological restoration and application potential of sewage sludge stabilization products
CHEN Si-si, DONG Bin, XU Zu-xin
This paper investigates and reviews the damage, pollution and hazards of mine lands, and then introduces the physical restoration, chemical restoration and phytoremediation technologies for mine lands in detail, as well as the in-situ treatment technology for acid mine drainage (AMD) in sulfur-bearing mines. The advantages and disadvantages as well as the application scenarios of these technologies are also investigated. From this, the basis for the selection of ecological restoration technologies for mine lands is summarized. That is, after the application of a series of technologies to eliminate pollution, the vegetation should be planted for the restoration and improvement of topsoil. It is pointed out that providing sufficient suitable covering matrix is the key to mine land ecosystem restoration. It is further proposed that the sludge stabilization products have huge potential for replacing foreign soils, preventing the generation of AMD, eliminating heavy metal pollution from mines, providing nutrients necessary for plant growth, and strengthening the water and fertilizer retention of mine lands. Moreover, the application of sludge stabilization products in the current rehabilitation of mine areas in China is sustainable in the long run. Therefore, sludge stabilization products have huge potential and advantages in the ecological remediation applications of mine lands.
2022 Vol. 42 (12): 5734-5747 [Abstract] ( 370 ) [HTML 1KB] [ PDF 729KB] ( 1234 )
5748 Effects of turning on the electron transfer capacity of humic substances in aerobic composting
LU Yi-ming, LI Jun, DAI Yu, MO Jin-tao, ZHANG Jun, XI Bei-dou
This study focus investigated the effects of two typical kinds of ventilation strategies (continuous aeration, turning) on the formation and electron transfer capacities (ETCs) of fulvic acid (FA) and humic acid (HA) during sewage-sludge composting by analyzing the temporal variation of spectrum features and the native/chemical reducing capability (NRC/CRC) of these two humic substances. The results showed that:compared with the turning, continuous ventilation promoted the reduction of protein-like fractions and the increase of humic-like fractions in FA and HA during the whole composting, enhanced ETCs of FA during the thermophilic and maturity phases (CRC increased 176.55μmol e-/gC, 123.24μmol e-/gC), but reduced ETCs of HA and FA during the heating phase (CRC decreased 246.47μmol e-/gC, 116.13μmol e-/gC). According to the results from the correlation analysis, the most important variables in influencing ETCs of humic substances were pH, SUVA254, SUVA290, and protein-like fraction; meanwhile, the turning improved the effect of humus-like fractions on the ETCs of the humic substances.
2022 Vol. 42 (12): 5748-5757 [Abstract] ( 250 ) [HTML 1KB] [ PDF 1169KB] ( 1052 )
Soil Pollution Control
5758 Spatial distribution and influencing factors of soil mercury in coastal wetlands of China
ZHANG Miao-miao, ZHANG Man-Yin, LONG Song-yuan, HU Yu-kun, LIU Wei-wei, WANG Zhao
In this paper, by measuring soil total mercury content (0~20cm), soil physical and chemical properties, climatic and social-economic factors in seven typical coastal wetlands, we studied the spatial distribution of mercury in coastal wetland soils and its relationship with driving factors, and analyzed the mercury content in different environments. The results showed that the total mercury content in coastal wetland soils in China ranged from 1.26ng/g to 169.94ng/g, with an average of 33.82±3.09ng/g. Soil mercury content in coastal wetlands was shaped by soil physical and chemical properties, social economic factors and climate factors, among which pH, organic matter, total iron and total nitrogen were the main factors. For the pathways of mercury input, the influence of river transport on soil total mercury content of coastal wetlands in China was higher than that of air transport.
2022 Vol. 42 (12): 5758-5767 [Abstract] ( 230 ) [HTML 1KB] [ PDF 848KB] ( 1193 )
5768 Effect of decomposition of polyethylene residue film on soil water infiltration
LIU Zi-han, CAI Lu, ZHAO Xiao-li, HAN Jian-qiao
To explore the effect of decomposition of residual film into microplastics on soil water infiltration, laboratory column experiments, which five residual film microplastics ratios (100%~0,75%~25%,50%~50%,25%~75%,0~100%) were included in, were conducted to study the effects on wet front and cumulative infiltration, and evaluate the applicability of the main infiltration models in soil with different degrees of decomposition. The results showed that the migration rate of wet front and cumulative infiltration increased with the degree of residual film decomposition. When the infiltration time was 300min, wet front position of completely decomposed residual film (T4) increased by 48.72%(P<0.05) compared with primary residual film (CK), and the cumulative infiltration increased by 46.77%(P<0.05). As the degree of residual film decomposition increased, model performance in simulating wetting front and cumulative infiltration appeared to be an upward trend. The parameter B of wetting front propulsion model increased with the degree of residual film decomposition. The parameter a of Kostiakov model and parameter S and C of Philip model increased with the degree of residual film decomposition. This study can provide a reference for soil water infiltration and simulation research in residual film polluted soil.
2022 Vol. 42 (12): 5768-5774 [Abstract] ( 189 ) [HTML 1KB] [ PDF 759KB] ( 708 )
5775 Heavy metals pollution characteristic in Panax notoginseng and planting soil and the associated risk assessment
LUO Zeng-ming, JU Yong-wang, ZHANG Hui-juan, DING Hao-jie, XU Qi-jing, LIU Xue
Panax notoginseng (P. notoginseng) and its growing soil from the main producing area Wenshan, Yunnan Province, were sampled and analyzed. The uptake and accumulation characteristics of Cd, As, and Pb were analyzed by determining their concentrations in soils and the aboveground and underground parts of P. notoginseng. The food safety risk and human health risk of Cd, As, and Pb in P. notoginseng were evaluated by analyzing their daily intake (ADI) and target hazard quotient (THQ). The results showed that. Cd and As concentrations in soils were 0.07~4.1 and 13.9~310 mg/kg, with standard-exceeding ratios being 63.2% and 79%, while Pb was within the standard values. The comprehensive pollution index P was >3, with an average value of 3.52, indicating that soil pollution reaches heavy pollution level. The proportion of soil samples with single factor pollution index PCd and PAs>1were 63.2% and 84.2%, indicating that soil Cd and As are at light pollution level. Cd, As, and Pb concentrations in P. notoginseng aboveground and underground parts were 0.05~0.69, 0.07~0.73; 0.25~1.06, 0.09~1.73; and 0.12~1.13, 0.07~0.66mg/kg dw, respectively. The standard-exceeding ratio of Cd was 26.3%~36.8% while As and Pb were within the standards, indicating P. notoginseng prefers to uptake Cd, thereby should be paid more attention. Cd concentrations in P. notoginseng and soil were significantly positively correlated (p<0.01), while for As and Pb were negatively correlated. Bioconcentration factor BCFCd was 0.03~3.5, while BCFAs and BCFPb were <1, which further indicated that P. notoginseng has a strong uptake ability for Cd. Translocation factor was in the order of TFPb (3.53)>TFAs (2.32)>TFCd (0.59), indicating that P. notoginseng prefers to accumulate Cd in the underground edible part, thus its food safety risk and human health risk deserve attention. Cd, As, and Pb daily intake indexes (ADI) of P. notoginseng were 0.0026~0.0035, 0.0043~0.0066, and 0.0026~0.0059mg/d, and the mean ADI percentages were 3.3%~4.7%, 4.3%~5.8%, and 1.2%~2.7%, indicating that Cd and As in P. notoginseng has high food safety risk (ADI>1%). The proportions of target hazard quotients THQ>1of Cd, As and Pb were 42.1%~68.4%, 84.2%~100%, and 0~31.6%, indicating that intaking Cd and As via long-term ingestion of P. notoginseng has potential human health risks.
2022 Vol. 42 (12): 5775-5784 [Abstract] ( 256 ) [HTML 1KB] [ PDF 480KB] ( 1295 )
5785 Effects of three calcium substances on plant bioavailability of arsenic in soil
MA Sheng, YANG Xiao-li, LIU Chao-zhu, XU Qi-jing, LIU Xue
This paper reviewed effects of calcareous materials (mainly including CaO, Ca(OH)2 and CaCO3, and others) on soil physicochemical properties (pH, composition and content of soil organic matter), microbial community, and As bioavailability, including impacts on As tolerance in plants, uptake and accumulation of As by plants. The review can provide theoretical and technical references for accurately understanding mechanisms under effects of calcareous materials on As bioavailability in soils and uptake and accumulation of As by plants, and then contribute to rationally select calcareous materials to improve soil physicochemical properties and reduce As bioavailability and its environmental risks in soils. It has certain practical significances for ensuring planting safety and food safety in agricultural field.
2022 Vol. 42 (12): 5785-5795 [Abstract] ( 234 ) [HTML 1KB] [ PDF 508KB] ( 786 )
5796 Level and source of 238Pu in Chinese terrestrial surface soils
ZHAI Shao-jing, ZHANG Hai-tao, LUO Mao-yi, YI Xiao-wei, LIN Jian-feng, ZHANG Wei-chao, ZHANG Zi-lu, DANG Hai-jun
To fill the lack of background data of 238Pu in terrestrial environment of China, the surface soil samples collected from different locations were analyzed for the plutonium isotopes content (238Pu, 239+240Pu). The results showed that the specific activities of 238Pu in samples were very low, in range of 0.007~0.045Bq/kg and the activity ratios of 238Pu/239+240Pu were in range of 0.032~0.041, similar to the reported data from neighboring countries and other mid-latitude locations in the northern hemisphere. A binary model was employed to attribute the origin of 238Pu in the environment, and the results suggested that the origin of 238Pu in surface soils be related most of all to nuclear weapon fallout and SNAP-9A fallout.
2022 Vol. 42 (12): 5796-5802 [Abstract] ( 215 ) [HTML 1KB] [ PDF 843KB] ( 688 )
Environmental Ecology
5803 Geochemical baseline establishment in grassland-type lake sediments in cold-arid regions: A case study in Dalinuoer Lake, China
LI He, JIANG Xia, WANG Shu-hang, CHE Fei-fei
In order to scientifically identify the accumulation of heavy metals in the sediments of Dalinuoer Lake, a typical grassland-type lake in cold-arid regions, the content of heavy metals in surface and core sediments were investigated, the geochemical baselines of heavy metals in the sediments were constructed by various statistical methods, and different baseline results were comparatively analyzed from many aspects. The results showed that: the 8 metals including Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb were distributed normally or log-normally in the surface and core sediments of Dalinuoer Lake, and the metal distributions in the core sediments were more concentrated than those in the surface sediments. The vertical distributions of As, Cd, Hg showed obvious increasing trends in the near surface layer, indicating a certain degree of enrichment. Three statistical methods including the reference element method, the relative cumulative frequency method and the iterative 2times standard deviation method were used to calculated the heavy metal baselines and there were no significant differences (P<0.05) among the baselines obtained by the above methods both in surface sediment and in core sediment. Considering scientificity,applicability, simplicity, and personal error, the iterative 2 times standard deviation method could be preferred to construct element baselines. The constructed geochemical baselines of heavy metals in Dalinuoer Lake sediments were different from the soil background values of heavy metals in large-scale regions, and the heavy metal baselines in surface sediment were also different from those in core sediment. Considering few human interference in Dalinuoer Lake Basin, the metal baselines of surface sediment were more useful for scientific and accurate identification in the current accumulation and ecological risks of heavy metals in the lake. The results could provide the important theoretical basis in constructing the metal baselines in similar grassland-type lake sediments in cold-arid regions.
2022 Vol. 42 (12): 5803-5813 [Abstract] ( 211 ) [HTML 1KB] [ PDF 732KB] ( 841 )
5814 Microbial bioavailability of dissolved organic matter in Qingdao coastal green tide area
WANG Zi-hao, FENG Li-na, ZAHNG Chuan-song, SHI xiao-yong
Dissolved organic matter (DOM) in the green tide region of Qingdao coastal was studied through indoor degradation experiments, the degradation efficiency of Dissolved organic carbon(DOC) in different seawater was calculated, and the fluorescent components and their variation of colored dissolved organic matter(CDOM) in the water were analyzed. The results showed that DOC in different sites and periods influenced by green tide had all been degraded, and the degradation process accorded with the first-order degradation kinetic equation, in which about 8.93%~45.10% of DOC could be utilized by microorganisms, and the degradation rate of the samples greatly affected by the outbreak of Ulva prolifera green tide was the highest. Based on usage of three-dimensional excitation and emission matrix fluorescence spectroscopy and parallel factor analysis, it was determined that CDOM in green tide water contains three humus components (C1, C2, C3) and one protein component (C4), and the content of protein like components in all samples was significantly higher than that of each single humus component, indicating that the main component of CDOM released by Ulva prolifera green tide is protein like component. In the degradation experiment, the change of protein like components was the same as the degradation trend of DOC content, while humus like components gradually increased. Meanwhile, the results of the support vector machine weight analysis and results of correlation analysis between the fluorescence parameters of CDOM and the percentage content of bioavailable dissolved organic carbon (BDOC%) showed that compared with BDOC, C4component was positively correlated and C1component was negatively correlated, indicating that the correlation between BDOC and CDOM components is very high. It can be inferred that protein-like component and BDOC are easy to be degraded and utilized by microorganisms, and humus-like component is more closely related to RDOC(refractory dissolved organic carbon). This study revealed the changes of DOM content in water during the Ulva prolifera green tide period and its corresponding relationship with different fluorescent components, which could provide a theoretical basis for explaining the causes of secondary ecological disasters caused by Ulva prolifera green tide, and could quickly infer the content of BDOC by using CDOM components and DOC, which offers convenience for marine field investigation.
2022 Vol. 42 (12): 5814-5823 [Abstract] ( 256 ) [HTML 1KB] [ PDF 1591KB] ( 829 )
5824 Estimation of DOC concentration in the surface water of Lake Bosten using CDOM absorption coefficient
JIANG Xin-tong, LIU Dong, ZHONG Pu, DUAN Hong-tao
This paper divide Lake Bosten into estuarine and non-estuarine regions based on 50sampling sites in the surface layer of Lake Bosten in the western arid zone in summer and autumn 2021, through statistical analysis of DOC characteristics, temporal and spatial differences in the influence of internal and external factors, and electrical conductivity correlation verification. Then, with the CDOM characteristic wavelength absorption coefficients a250 and a365 as independent variables and DOC concentration (cDOC) as the dependent variable, the CDOM-based estimation model of DOC concentration in estuarine and non-estuarine waters was constructed respectively. The results showed that the exchange of water between the river and the lake would transport a large amount of terrestrial DOC into Lake Bosten, making the DOC concentration in the estuary area significantly higher than that in the non-estuarine area (t-tests, P<0.01), and the DOC concentration in the estuary area was about 2.2~2.3times that in the non-estuarine region, and cDOC was significantly correlated with conductivity in the estuarine region (summer:R2=0.81, P<0.01; autumn:R2=0.84,P<0.01). This paper construct a fitting model(cDOC=α+β·α250+γ·α365), and test the accuracy of the model by cross-validation. Unified modeling of the same area data in summer and autumn, there is a good correlation between CDOM and DOC in both estuary and non-estuarine areas, and the model accuracy is high (estuary area:R2=0.60, RMSE=8.56%; non-estuarine area:R2=0.66, RMSE=8.77%). The model established in this paper can improve the accuracy without increasing the environmental factor variables, which is beneficial to the realization of satellite remote sensing inversion. At the same time, the spatiotemporal effects of river input on DOC distribution and estimation in Lake Bosten were revealed, and it was proposed that CDOM could be used to estimate DOC concentration, but estuarine and non-estuarine areas should be distinguished according to factors such as hydrological characteristics and cDOC. This study provides a scientific basis for the rational development, effective protection and comprehensive management of water resources in Xinjiang, and is of great significance to the dynamic monitoring of lakes in the western arid zone of China.
2022 Vol. 42 (12): 5824-5835 [Abstract] ( 234 ) [HTML 1KB] [ PDF 1041KB] ( 646 )
5836 Effect of nFe3O4 capping on arsenic release at sediment-water interface
YAN Yu-lin, YAN Wen-ming, QIAN Bao, CHEN Xiang, HE Xiang-yu, XIAO Xiao, WU Ting-feng
In order to reveal the passivation effect of nano-iron tetroxide (nFe3O4) covering on soluble arsenic (As) and labile As in sediments, on the basis of laboratory culture experiments, micro-interface analysis technology, high-resolution equilibrium gap Water harvesting technology (HR-peeper) and Diffusive Gradients in Thin-films technology (DGT) were used to explore the mechanism of action of As in the redox environment, iron and manganese content of sediments covered by nFe3O4. The results showed that the pH value of the sediment under the coverage of nFe3O4 gradually increased compared with the control group, and the Eh first decreased and then increased; nFe3O4 could effectively remove dissolved As from sediments, the maximum effective removal rate was 22%; the average value of available As was reduced by 2.30μg/L by the coverage of nFe3O4; There was a significant positive correlation between solube As, solube Fe(II) and solube Mn (P<0.001). Similarly, there was also a significant positive correlation between labile As, labile Fe(II) and labile Mn. (P<0.001); the coverage of nFe3O4 could promote the increase of the content of amorphous Fe and Al oxides bound.
2022 Vol. 42 (12): 5836-5844 [Abstract] ( 204 ) [HTML 1KB] [ PDF 806KB] ( 808 )
5845 Advances in fractional advection-diffusion models for anomalous solute transport in groundwater
WANG Jing-rui, ZHAO Jian-shi, HU Shi-ruo
Solute transport in underground heterogeneous porous media does not always follow Fick's law of diffusion and is thus called anomalous diffusion or transport. The transport is essentially a kind of non-Markovian and nonlocal process. Fractional advection-diffusion models can provide an adequate and accurate description of this transport of solute in an aquifer. After illustrating the fundamental problems of anomalous solute transport in groundwater and its dynamics mechanism, we reviewed three types of fractional advection-diffusion models, i.e., the space, time, and distributed-order fractional advection-diffusion ones, and also discussed the prospect and challenges in the application of fractional advection-diffusion models to anomalous solute transport in groundwater in detail.
2022 Vol. 42 (12): 5845-5855 [Abstract] ( 262 ) [HTML 1KB] [ PDF 692KB] ( 1806 )
5856 Impact on denitrification potential and threshold of ditches sediment with exogenous carbon and nitrogen addition: A case of ditches in Ningxia Yellow River Irrigation area
ZHAO Jun-han, SHE Dong-li, GE Jia-min, SHAN Jun, PAN Yong-chun, XIA Yong-qiu, HONG Yu
In this study, laboratory incubation experiments were conducted for sediment denitrification potential study in farmland ditches of the Yellow River Diversion Irrigation Area of Ningxia. Experiments were conducted under condition of four exogenous nitrogen concentration gradients of 0, 5, 10, 20mg/L and two exogenous carbon concentration gradients of 0 and 100mg/L in the overlying water. The NO3--N, NH4+-N, and DOC concentration of the overlying water were measured as well as denitrification rates during 47days of incubation to evaluate the denitrification potential and its threshold. The results showed that sediment denitrification increased with the increase of exogenous nitrogen and of carbon. The NO3--N concentration of the overlying water decreased with the time (P<0.01), but the concentration of NO3--N in the overlying water decreased significantly with the addition of exogenous carbon compared with the condition without carbon source (P<0.05). At the end of the experiment, NO3--N concentration decreased by 52.1% and 93.6% respectively without and with carbon sources. Under the condition of adding carbon source, the concentration of NO3--N in the overlying water stabilized to a low level at 20d, while the concentration of NO3--N in the treatment without carbon source addition still had a large decreasing space after 47d of the incubation. The thresholds of denitrification removal rate in sediment without carbon source and with carbon source were 263.7 and 865.6µmol/L, respectively. The ratio of cumulative nitrogen removal to total nitrogen in the culture column system increased with the increase of exogenous nitrogen and carbon source (P<0.05), denitrification process could remove 10.3%~11.4% of nitrogen in the culture column system without exogenous carbon, but increased to 17.7%~37.3% with the exogenous carbon addition. In conclusion, This study can provide scientific basis for efficient control of agricultural non-point source pollution in the irrigated area of Yellow River diversion.
2022 Vol. 42 (12): 5856-5863 [Abstract] ( 273 ) [HTML 1KB] [ PDF 508KB] ( 1620 )
5864 Air-plant/soil exchange process and flux of polycyclic aromatic hydrocarbons in winter in the typical water-level-fluctuation zone of the Three Gorges Reservoir region, China
XIE Dong-hang, WANG Feng-wen, LIU Wen-xing, ZHANG Si-yuan
Affected by the seasonal "storage-discharge" of the Three Gorges Dam, the water level fluctuation zone (WLFZ) of the Three Gorges Reservoir Region (TGRR) show a periodic change of "submergence-exposure" each year, and the environmental geochemical processes of organic matter in this area changed accordingly. This study took polycyclic aromatic hydrocarbons (PAHs) as the targeted compounds. The coupled air, plant and soil samples (n=40) were consecutively collected. These samples were analyzed for USEPA 16PAHs to explore their composition characters and estimate the air-plant/soil exchange flux. The concentration of PAHs in air, soil and plants were 5.65~13.47ng/m3, 70.86~135.44ng/g, 78.23~1084.72ng/g, with an average of (8.58±2.78) ng/m3, (90.10±22.18) ng/g and (360.36±309.54) ng/g respectively. 2 to 3 ring PAHs dominated in the air, contributing 62.3% of the total. 3 to 4 ring PAHs dominated in plants, with a contribution of 73.3%. 3 and 5 ring PAHs in dominated soil, accounting for 52.1% of the total. The molecular diagnostic ratio of PAHs indicated that petroleum could be the main source of PAHs in plant. Biomass and fossil fuel combustion were the main sources of PAHs in air and soil. "One-compartment model" indicated that the main way for plants to absorb PAHs was gaseous deposition which was restricted by the plant-gas dynamic equilibrium. The fugacity model showed that the air-soil exchange flux of 3-ring, 4-ring and 5~6-rings PAHs were -19.20, -0.14 and 0.89, respectively. 3~4rings PAHs in the soil were mainly re-volatile into the atmosphere, while 5~6 rings in the atmosphere mainly deposited into the soil. The dry deposition flux of PAHs was between 293.35 and 833.61ng/(m2·d), with an average of 517.82ng/(m2·d) and dominated by 5~6 rings (59.02%). As investigating the multi-medium exchange process of PAHs in winter, this study could reveal the absorption and deposition role of different monomial PAHs by plants and soil. These datasets provide important basis for further study on environmental geochemical cycle of PAHs in different seasons in the TGRR.
2022 Vol. 42 (12): 5864-5876 [Abstract] ( 285 ) [HTML 1KB] [ PDF 1371KB] ( 1043 )
5877 Effects of aged polystyrene nanoplastics to Microcystis aeruginosa.
HE Yi-xin, TANG Bing-ran, ZHANG Li-xue, QU Jin-yao, LI Hong
To investigate the effects of pristine and aged polystyrene nanoplastics (PSNPs) on the growth and toxin-producing ability of Microcystina aeruginosa, 50nm aged PSNPs was prepared by UV aging method, and long-term exposure of different concentrations (0.1, 1, 10mg/L) of pristine and aged PSNPs to Microcystina aeruginosa was conducted for 37days. The results showed that cracks appeared on the surface of aged PSNPs, meanwhile the average particle size was reduced, and the carbonyl index increased from 0.023 to 1.055. Both pristine and aged PSNPs would aggregate on the cell surface of Microcystis aeruginosa, in which the exposure of aged PSNPs caused severer cell morphological damage, and triggered dose-related growth and photosynthesis inhibition, oxidative damage and promotion of microcystin (MC-LR) synthesis and release. Compared with the control group, the final density of Microcystis aeruginosa in 10mg/L pristine and aged PSNPs treatments decreased by 26.65% and 45.07%, the highest malondialdehyde (MDA) content was 1.74 and 1.93 times of the control, and the final extracellular MC-LR content was 1.26 and 1.44 times of the control, respectively The relatively higher promotion of extracellular MC-LR content under 10mg/L of aged PSNPs exposure at the end of the experiment was resulted from the increased synthesis of intracellular MC-LR and the damage of cell membrane.
2022 Vol. 42 (12): 5877-5884 [Abstract] ( 239 ) [HTML 1KB] [ PDF 1445KB] ( 774 )
5885 Plant composition diversity and community stability under vegetation succession in relation to soil aggregates
TIAN Qi-long, ZHANG Xiao-ping, WANG Miao-qian, WANG Hao-jia, YI Hai-jie, HE Jie, XU Xiao-ming, LYU Du, SUN Wei-nan
In order to reveal the relationship between the diversity of plant composition, community stability, and soil aggregates in the process of natural vegetation restoration, and further to prevent soil erosion and improve soil quality, field survey and sampling were performed to determine vegetation characteristics and soil aggregation at different stages of vegetation succession on the Loess Plateau over the past 150 years. The results showed that there were 128 species of seed plants belonging to 39 families and 99 genera in the succession process. The dominant families were Asteraceae, Rosaceae, Gramineae, and Leguminosae, and the dominant genus was Artemisia. The plant genera in this process were characterized as monotypic genera. The plants with a high frequency of occurrence included Carex lanceolata, Lespedeza bicolor, Sophora davidii, Cotoneaster multiflorus, Artemisia caruifolia, Ostryopsis davidiana, Quercus wutaishanica, Acer tataricum subsp.ginnala, Pinus tabuliformis, Spiraea salicifolia, Aster hispidus, etc. At the genus level, the geographical composition had 11 types and 8 variants, in which the temperate geographical components had a distinguished superiority. The ratio (i.e., R/T values) of tropical (R-value) and temperate (T-value) properties decreased with increasing recovery years. The R-value correlated significantly with the R/T value, and the spread of tropical components was limited. The time series of plant diversity exhibited a single-peaked curve, with the maximum occurring between 40~70 years after restoration. The stability of the community could be ranked according to different restoration years as follows:70 > 120 > 135 > 150 > 40 > 10 > 20 > 0years. The R-value and the T-value were both significantly positively correlated with germline differentiation (i.e., SD values) and community stability, respectively. > 5mm particle size aggregates were related to the plant richness driven by tropical species, while community stability was associated with >0.25mm grain size clusters maintained by temperate species. As the key species to maintain community stability in the process of vegetation succession, Carex lanceolata, Lespedeza bicolor, and Sophora davidii are functional plants with the potential to increase the proportion of large-sized soil aggregates. These three species can be considered for near-natural vegetation restoration, soil quality improvement, and soil erosion control.
2022 Vol. 42 (12): 5885-5895 [Abstract] ( 233 ) [HTML 1KB] [ PDF 2675KB] ( 818 )
Environmental Toxicology and Health
5896 Contamination and health risk of precursors of PFAAs in urban aquatic environment
ZHANG Yue-qing, ZHAO Ya-xin, YU Jia, CAO Li, KONG De-yang
In order to characterize the input, distribution and health risk of precursors of perfluoroalkyl acids (PFAAs) in the urban aquatic environment, the effluents of wastewater treatment plants, rivers, lakes and drinking water sources in the Yangtze River in Nanjing were investigated. HPLC-MS/MS and the total oxidizable precursor assay (TOP Assay) were used to analyze 17PFAAs and their total oxidizable precursors. Their health risk quotient (HQ) was assessed based on the tolerable dose interpretation. The results suggested in the effluents PFAAs concentration was 90.6~278ng/L, and the dominant homologues PFBS, PFHxA, PFOA accounted for 63%. The total oxidizable precursors concentration was 239~839pmol/L, and PFBA predominated among the precursors. PFAAs concentration in urban surface water was 61.8~157ng/L, and the concentration of total oxidizable precursors was 195~572pmol/L. PFBA, PFPeA and PFHxA displayed the highest concentration of precursors. PFAAs level in the urban rivers increased while oxidizable precursors level decreased. PFAAs concentration in drinking water sources was 50.9~54.6ng/L, and the total oxidizable precursors concentration was 273~372pmol/L, predominated by the precursor of PFBA, PFPeA and PFHxA. The relatively high risk was immunotoxicity from PFOS (HQ=0.024) and developmental toxicity (HQ=0.0073) and reproductive toxicity (HQ=0.0039) from PFOA. Transformation of oxidizable precursors could increase their potential risk by 23% and 40%. The widespread presence of precursors in aquatic environments may increase the environmental exposure and health risks of PFAAs.
2022 Vol. 42 (12): 5896-5904 [Abstract] ( 294 ) [HTML 1KB] [ PDF 768KB] ( 1108 )
Carbon Emission Control
5905 Temporal and spatial variation and prediction of carbon storage in urban agglomeration on the northern slope of Tianshan Mountains
REHEMAN·Rukeya, KASIMU·Alimujiang, DUOLAT·Xilinayi, WEI Bohao, ZHANG Xue-ling, LIANG Hong-wu
In order to effectively assess carbon stock changes in urban agglomerations, the PLUS model and the InVEST model were used in this study to dynamically assess land use changes and carbon stock changes under different scenarios from 2000 to 2020 and in 2030 in the urban agglomeration on the northern slope of the Tianshan Mountains. The results revealed that the carbon stock of the urban agglomeration on the northern slope of Tianshan Mountains showed a continuous increasing trend from 2000 to 2020, which was closely related to the land use change. Specifically, the decrease in forest land area from 2000 to 2010 led to a decrease in carbon stock by about 266×106t, and the increase of grassland area from 2010 to 2020 gave rise to an increase in carbon stock by about 69.14×106t. In 2030, the carbon stocks under scenarios of natural development, ecological protection and rapid economic development were 8875.88×106t, 8895.58×106t and 8841.58×106t respectively, with the lowest carbon storage under rapid economic development scenario and the highest carbon storage under ecological protection scenario. Land use was the first dominant factor influencing the distribution of spatial changes in carbon stocks, with a contribution rate close to 90%, which was further verified by the analysis of the coordination between land use intensity and carbon stocks and the bivariate spatial autocorrelation between the two. To a certain extent, land use changes could exert a positive impact on carbon stocks. For the area in this study, the ecological conservation development scenario might be more in line with the future urban development pattern. As a result, the results of the study could provide some scientific reference for land use planning.
2022 Vol. 42 (12): 5905-5917 [Abstract] ( 386 ) [HTML 1KB] [ PDF 2565KB] ( 771 )
5918 Spatial patterns of partial pressure of carbon dioxide and its exchange flux in karst lakes and reservoirs in a metropolis
LI Yuan-yuan, WANG Zhi-kang, Irumva Olivier, MA Yong-mei, NI Mao-fei, WU Yun-jie
The typical karst lakes and reservoirs including AHa Reservoir (AHa), Songbaishan Reservoir (SBS), Baihua Lake (BHH) and Hongfeng Lake were investigated regarding spatial patterns of partial pressure of CO2 (pCO2) and CO2 exchange flux (F) in this study. We examined in-situ hydrometeorologic parameters, carbonate equilibria and environmental factors, as well as their potential constraints on water-air CO2 exchange. The higher pCO2 levels were observed in the AHa (861.6±462.8) μatm in comparison to the SBS (223.6±213.1) μatm, BHH (139.3±63.6) μatm and HFH (126.2±50.9) μatm (P<0.05). Gas transfer velocity of CO2 (k values) varied between 2.05~3.82cm/h. The F values were respectively (6.23±9.59) mmol/(m2·d), (-5.86±5.25) mmol/(m2·d), (-8.63±1.03) mmol/(m2·d) and (-7.58±1.10) mmol/(m2·d) in the AHa, SBS, BHH and HFH, indicating that karst lakes and reservoirs served as both CO2 sink and source with respect to the overlying atmosphere. Aquatic pCO2 was tightly linked to chlorophyll a (Chla) and ammonia nitrogen (NH4+-N), suggesting that surface water CO2 levels responded to coupled carbonate dissolution with photosynthesis and regional human inputs in the karst waters.
2022 Vol. 42 (12): 5918-5927 [Abstract] ( 224 ) [HTML 1KB] [ PDF 1249KB] ( 1442 )
Environmental Impact Assessment and Management
5928 Counties' economic effect of ecological protection policies in China: Evidence from national key ecological function zones
MA Ben, SUN Yi-dan, QIN Lu
To ensure the supply of ecological products, China established the National Key Ecological Function Zones (NKEFZ) and initiated a central general equalized transfer payment project. By employing county-level panel datasets from 2002 to 2017, this paper used the Propensity Score Matching to construct a "counterfactual" scenario for the policy group, and evaluated the income effect based on the difference-in-difference strategy. Results show that the policy has improved the financial resources of counties and improved the industrial structure to a certain extent in the long run; the funding allocation mechanism based on the standard financial gap has weakened the incentives for county economic development, and the financial subsidies cannot fully offset the negative impact of development restrictions on county economies; fixed asset investment and domestic enterprises are more affected. With the accumulation of investment funds and the transformation of ecological product value, the negative effect will weaken over time and the economic promotion effect will gradually appear. The policy effect shows obvious heterogeneity among different ecological functions and economic zones. It is recommended to continuously increase the ecological transfer funds, use the quantity and quality of ecological product supply as the basis for fund allocation, and consider designing differentiated policies according to ecological function types to better stimulate the win-win situation between the high level of ecological product supply and economic value realization in counties and facilitate balanced regional development.
2022 Vol. 42 (12): 5928-5940 [Abstract] ( 294 ) [HTML 1KB] [ PDF 556KB] ( 809 )
5941 Spatiotemporal dynamics of ecosystem services and their nonlinear influencing factors-A case study in the Qiantang River Basin
LI Gui-e, LI Jie, ZHAO Chong, JIAO Yang-yang, YAN Qing-wu
In order to unravel the impacts of different categories of influencing factors across scales on different types of ecosystem services, this paper measured 7 ecosystem services and untangled their spatiotemporal changes from 2010 to 2017 within the Qiantang River Basin, China. The magnitude and relative importance of influence for natural factors and socio-economic factors across different scales of each ecosystem service type are identified using the random forest algorithm, and the marginal effects of the dominant influencing factors are quantified. The results showed that ecosystem services presented obvious spatially heterogenous characteristics. Different types of ecosystem services were jointly affected by varying natural factors and socio-economic factors across scales, but their influence degrees varied with types. The natural environmental factors at grid scale had relatively larger influence. The changes of construction land, cultivated land and directly related socio-economic factors shaped the evolution process of ecosystem services. There existed a complex nonlinear relationship between the leading influencing factors and individual ecosystem services. The change of the indicators of each influencing factor had a non-stationary impact on ecosystem services in each year. For example, the impact of the initial increase of construction land was much more complex and intense for many ecosystem services.
2022 Vol. 42 (12): 5941-5952 [Abstract] ( 303 ) [HTML 1KB] [ PDF 4915KB] ( 905 )
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