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  Current Issue
 
2022 Vol.42 Issue.11,Published 2022-11-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Ecology
Environmental Impact Assessment and Management
Environmental Toxicology and Health
Air Pollution Control
4961 Effects of Nanjing fog process on the spectral distribution and chemical composition of atmospheric aerosols
ZHANG Si-rui, FAN Shu-xian, WANG Yuan, HU Chun-yang, ZHANG Hong-wei, ZHU Dan-dan, GE Pan-yan
In order to explore the effects of fog process on the chemical composition and size distribution of aerosol particles in Nanjing. Three-stage fog samples and particle-size aerosol samples were collected at the same time in the fog observation in winter 2017. The microphysical quantity and aerosol spectral distribution of fog, the chemical composition of three-stage fog samples and particle-size aerosol samples before, in and after fog were compared and analyzed. The results showed that: in the winter of 2017, the fog droplet liquid water content of the first fog process in Nanjing was in the shape of asymmetric "V" with the particle size distribution, and the lowest value was located at 7μm. The fog droplet liquid water content in the second fog process was a 3peak shape with the particle size distribution, and the peaks were located at 5, 15and 21.5μm. The mass concentration of small particle size aerosol decreased while that of large particle size aerosol increased in the stage of fog formation and development. The mass concentration of aerosol particles reached the lowest in the whole particle size in the stage of fog maturity, and the mass concentration of larger particle size aerosol decreased significantly. Compared with that before fog, the peak value of aerosol mass concentration after fog moved to the direction of large particle size. Before fog, the water-soluble ion components in aerosol were enriched in small particles with particle size<0.43μm, with the progress of fog process, nucleation and hygroscopic growth lead to the enrichment of water-soluble ions to larger particle size. The newly generated aerosol in the fog was released with the evaporation of fog droplets, resulted in the increase of NO3-, SO42- and NH4+ concentrations after fog. The neutralization rate of aerosol with smaller size was higher, and the new droplets in the early stage of fog formation were more acidic. With the gradual neutralization of fog process, the pH value of fog water increased.
2022 Vol. 42 (11): 4961-4973 [Abstract] ( 240 ) [HTML 1KB] [ PDF 2271KB] ( 1681 )
4974 Distribution characteristics of organic markers in particulate matter with different sizes during different seasons in Tianjin
WANG Xiao-ning, TIAN Ying-ze, XUE Qian-qian
In order to study the distribution characteristics of organic markers in particulate matter with different sizes during the heating and non-heating period, and identify their pollution sources, the Anderson eight-stage sampler was used to collect one-year samples from May 2018 to April 2019. 17 kinds of polycyclic aromatic hydrocarbons(PAHs), 20kinds of n-Alkanes and 7kinds of hopanes in 9particle size segments were analyzed and the main sources of particulate matter were identified by molecular markers and diagnostic ratios. The results showed the 4~5rings PAHs Pyr, BaA, Chr, BbF and BaP showed a three-peak distribution and the rest of the PAHs showed a bimodal distribution during the non-heating period, and 3rings PAHs showed a bimodal distribution and 4~6rings PAHs showed a approximately unimodal distribution during the heating period. The diagnostic ratios of PAHs indicated that vehicle emissions and coal combustion were the main contributors of PAHs during the non-heating period and the coal combustion was the main contributors of PAHs during the heating period. The n-Alkanes showed a stable bimodal size distribution during the heating period and C29 showed a unimodal distribution, C27, C31, C32 and C33 showed approximately a unimodal distribution, with the remaining n-Alkanes in a bimodal distribution during the non-heating period. According to the CPI and Cmax, it is found that anthropogenic sources were the main source of n-Alkanes during the non-heating period and the heating period. The concentration of high molecular weight n-Alkanes was better influenced by natural sources during the non-heating period than during the heating period. In addition, n-Alkanes emitted from natural sources were easy to concentrate in coarser particulates, and n-Alkanes from anthropogenic sources were more likely to concentrate in the finer particles. The hopanes had peaks in both coarse and fine particle modes during two seasons. Traffic was proposed as the main emission source of hopanes during the non-heating period, and the hopanes mainly originated from coal combustion during the heating period.
2022 Vol. 42 (11): 4974-4982 [Abstract] ( 231 ) [HTML 1KB] [ PDF 439KB] ( 1117 )
4983 Monitoring atmospheric NO2 concentrations in China based on Sentinel-5P satellite products
LIU Yi-yang, XIE Yao-wen, GUO Ze-cheng
NO2 is an important trace gas and its monitoring contributes to air pollution control. Based on the tropospheric vertical column and total vertical column of NO2 provided by the Sentinel-5P air pollution monitoring satellite, we analyzed spatial-temporal characteristics of NO2 in China during 2018~2021 by Google Earth Engine (GEE) and revealed the main drivers of NO2 concentration using OLS model. Results showed that there were a spatial pattern with high in the east and low in the west regarding the tropospheric vertical column of NO2 in China. A seasonal pattern with high in winter, low in summer and excessive in spring and autumn, was presented in the eastern and central city clusters and Urumqi city. The western cities, however, had less significant changes within seasons. The concentration distribution of tro NO2 in Beijing, Shanghai and Shenzhen showed a significant circle structure. The OLS model results showed that the atmospheric NO2 concentration in China was influenced collectively by socio-economic and natural factors, with the degree of urbanization being the critical factor driving NO2 emissions.
2022 Vol. 42 (11): 4983-4990 [Abstract] ( 426 ) [HTML 1KB] [ PDF 2003KB] ( 2415 )
4991 Effect of regional transport on ozone pollution in Tianjin
FAN Wen-yan, CAI Zi-ying, YAO Qing, WANG Xiao-jia, TANG Ying-xiao, HAN Su-qin
The atmospheric chemistry model was used to quantitatively estimate the impact of regional transport on the ozone (O3) concentration in Beijing-Tianjin-Hebei region during April to September of 2019, and Tianjin was the focus of analysis. Additionally, the relationship between the weather pattern and meteorological conditions with O3 regional transport was also analyzed. The results showed that O3 pollution of 13 cities in the Beijing-Tianjin-Hebei region was mainly attributed to regional transport, with distinguished contribution in different cities. The local generation for O3 pollution in Tianjin accounted for 24%. The O3 regional transport from other cities in the Beijing-Tianjin-Hebei region and Shandong province totally accounted for48.3%. O3 regional transport occurred frequently under the weather pattern of low pressure, front and rear of low pressure. The southern air flow passed Tianjin was an important factor generating high O3 concentration, and it was the main pathway of O3 regional transportation for Tianjin. With the rise of O3 concentration, the contribution of O3 regional transportation increased gradually, and the contribution of O3 regional transportation was comparative to local generation in severe O3 pollution. The analysis of a typical O3 pollution event showed that the high temperature and strong radiation as well as favorable weather pattern promoted the local formation of O3. The O3 regional transport from southwest direction and weak downdraft jointly maintained this O3 pollution event for 3 days.
2022 Vol. 42 (11): 4991-4999 [Abstract] ( 275 ) [HTML 1KB] [ PDF 1674KB] ( 1745 )
5000 Characteristics and main causes of ozone pollution in the Pearl River Delta in 2020
CHEN Duo-hong, SHEN Jin, CHEN Yao-yao, ZHOU Yan, ZHANG Tao, LIAO Tong, LIAO Cheng-hao, ZHAO Wen-long, WANG Bo-guang, LI Ting-yuan
Based on the regulatory monitoring of atmospheric pollutants and components and meteorological data, the characteristics and main causes of ozone pollution in the Pearl River Delta (PRD) in 2020 were studied and analyzed. The results showed that ozone was the primary air pollutant in each month in the PRD in 2020. The annual concentration of ozone was 148mg/m3, decreased by 16% on a year-on-year basis, and the AQI compliance rate increased by 9.5%. The months with relatively serious ozone pollution in 2020 were April, August to November. The corresponding monthly ozone concentrations reached 175, 164, 166, 171 and 162mg/m3, respectively, all exceeding the national air quality standard of the secondary level of 160mg/m3. In other months, the ozone concentrations met the standard. From June to December, the ozone pollution conditions improved significantly compared in 2019, and thus increased the AQI compliance rate significantly year-on-year. In the first quarter of 2020, the emission of air pollutants decreased significantly due to the Spring Festival holiday and epidemic factors. However, the decrease in ozone concentration was not obvious, mainly because of a yearly increase in sunshine hours by about 19%. The comprehensive resumption of work and production in the PRD in April and the meteorological conditions with relatively strong radiation increased the ozone concentration by about 58% year-on-year. The pollution control measures taken in the “100-day service” from May to August and the “100-day action”from September to December effectively reduced the emission of ozone precursors. The concentration of NO2 decreased by 22%~23% and the concentration of VOCs decreased by 18%~26%, resulting in the concentration of ozone in these two stages decreasing by about 20% year-on-year.
2022 Vol. 42 (11): 5000-5007 [Abstract] ( 351 ) [HTML 1KB] [ PDF 383KB] ( 3880 )
5008 Spatiotemporal characteristics of ambient air pollutants in five border cities of Yunnan province: variations
LANG Li-jun, CUI Xiang-fen, SHI Jian-wu, HUANG Jian-hong, NING Ping, HAO Ji-ming
The pollution characteristics, spatiotemporal variation and spatial heterogeneity was explored based on ambient particulate matter (PM with diameter £2.5µm [PM2.5], £10µm [PM10]) and gaseous pollutants (Ozone [O3], sulfur dioxide [SO2], nitrogen dioxide [NO2], carbon monoxide [CO]) data collected from 2015 to 2021 in five border cities of Yunnan province. Annual average concentrations of ambient air pollutants fluctuate enormously and that of PM10 (42.6±8.2)µg/m3 and PM2.5 (25.4±4.2)µg/m3 exceed the Grade Ⅱ limit value recommended the Chinese Ambient Air Quality Standards (GB 3095-2012). The monthly average concentrations showed a U-shaped trend for PM, NO2 and O3-8h, and their concentrations peaked in March. PM and NO2 concentrations followed a comparable seasonal pattern: spring>winter>autumn>summer. By contrast, seasonal average concentration of O3-8h decreased as: spring>summer>autumn>winter and that of CO was the lowest in winter. In addition, SO2 showed no obvious seasonal variation. Sen-MK results indicated a general trend of descending in daily average concentrations of ambient air pollutants and PM10 had the highest decline rate at 11×10-3µg/m3 per day, while an inverse trend of O3-8h. The coefficient of variation (COD) revealed that the spatial distribution of ambient air pollutants is extremely uneven, especially for SO2 with COD>0.2 but that of O3-8h was more uniform in spring. Person correlation analysis supported a strong correlation between PM and NO2, CO as well as O3-8h, and correlations between PM and other pollutants are stronger in Xishuangbanna (BN) than other studied cities.
2022 Vol. 42 (11): 5008-5015 [Abstract] ( 203 ) [HTML 1KB] [ PDF 2372KB] ( 1160 )
5016 Effects of vertical wind shear on PM2.5 concentration under two pollution weather types
WU Jin, LI Chen, WANG Zhi-li, MA Zhi-qiang, LI Zi-ming, ZHU Xiao-wan, HAN Ting-ting, TANG Yi-xi, MA Xiao-hui
Based on the ecological environment monitoring data and multi-source meteorological data from 2015 to 2020 in Beijing-Tianjin-Hebei region, this study analyzed the evolution characteristics of 0~3km VWS at different PM2.5 levels in Beijing. The diurnal variation characteristics of wind speed gradually weakened with the increase of PM2.5 concentration. When PM2.5 level 6pollution occured, the diurnal variation of near-surface wind speed basically disappeared or even changed in reverse direction. The VWS below 10m/(s·km) corresponded to the increase of boundary layer wind speed in the daytime which increased to 12~14m/(s·km) after 20:00. This phenomenon became more significant with the increase of PM2.5, and the VWS near the stratum remains small (<6m/(s·km)) in the daytime could be one of the signs of serious pollution. Based on the rotated empirical orthogonal function (REOF) decomposition method, the VWS was divided into two types which called undisturbed type and compression type. The low pressure intensity of compression type was slightly better than undisturbed type; the PM2.5 peak and daily value and inversion of undisturbed type were higher than compression type. In addition, the PM2.5 growth of the undisturbed type and PBLH reverse change and the PM2.5 growth of compressed type changed in the same direction as Planetary Boundary Layer Height (PBLH).
2022 Vol. 42 (11): 5016-5022 [Abstract] ( 272 ) [HTML 1KB] [ PDF 1736KB] ( 1133 )
5023 Analysis of transport pathways and potential source regions of PM2.5 in Jinghong from 2015 to 2021
LIU Xu-yan, HAN Xiu-zhen, LIANG Lin-lin, ZHU Lin
This study analyzed the characteristics of air pollutants in Jinghong City from 2015 to 2021, and obtained the months when the daily PM2.5 exceeded the Class-2limit values of the National Ambient Air Quality Standard (NAAQS). Based on Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, 72-hour daily backward trajectories in those months were calculated, combined with PM2.5 concentration, the transport pathways and potential source regions during those months in Jinghong city were determined through the methods of analysing cluster, potential source contribution factor and concentration weighted trajectory factor. The results shown that the months of PM2.5 exceeding standard were concentrated on February, March, April and May in Jinghong City. The transport pathways of PM2.5 during February to May in Jinghong City mainly originate from west, southwest and south, with medium and short-range, and low-altitude transports corresponded to high concentration of PM2.5 pollution. The potential source regions of PM2.5 in Jinghong during February to May were mainly located in the central region of Myanmar, the northwest region of Laos and the northern region of Thailand. The results of normalized concentration weighted trajectory factor exhibited that the source regions of PM2.5 in Jinghong City during February to May were concentrated in Myanmar, accounting for 41%~50%, with Thailand and Laos accounting for 21%~27%, 5%~12%, 2% and 2%, respectively. To further investigate the sources of the PM2.5 in Jinghong, the distribution of fires counts in the indo-China and its correlation with PM2.5 in Jinghong from 2015 to 2021 were analyzed. Further results demonstrated that the main source of PM2.5 in Jinhong city during February to May was open biomass burning from Myanmar. These results in this study have guiding significance for Jinghong city to establish cross-border regional joint prevention and control measures and to study future climate change.
2022 Vol. 42 (11): 5023-5035 [Abstract] ( 196 ) [HTML 1KB] [ PDF 4234KB] ( 1079 )
5036 Chemical characterization and source apportionment of fine particulate matter in Shanghai during 2016~2020
ZHAO Qian-biao, HU Ming, FU Qing-yan
A systematic observation of particulate matter was carried out from 2016 to 2020 at six urban and suburban sites in Shanghai. Chemical species including water-soluble ions, organic carbon/elemental carbon, and inorganic elements of fine particulate matter (PM2.5) were analyzed. Source apportionment of PM2.5 was conducted using the Positive Matrix Factorization model. Results show that the annual PM2.5 mass concentrations of Shanghai from 2016 to 2020 were 46, 43, 37, 40, and 39μg/m-3 successively, exhibiting a decreasing annual trend and spatiotemporal features of higher in the west and in winter while lower in the east and in summer. Organic aerosol was the most abundant species in PM2.5 (30%~32%), with small annual and seasonal variations. Secondary inorganic ions including sulfate, nitrate and ammonium showed an evidently regional characterization. Among all the inorganic species, nitrate played an important role in pollution episode in winter, and its proportion increased the most from 2016 to 2020. Nine PM2.5 sources were identified, including secondary nitrate (30.6%), secondary sulfate (20.7%), vehicle emission (12.6%), industry (8.0%), biomass burning (7.7%), dust (6.5%), coal combustion (5.8%), sea salt (4.8%) and ship emission (3.2%). Owing to the atmospheric emission control strategies, the contributions of mobile sources including vehicle and ship emissions as well as biomass burning sources including straw burning and fireworks emission showed a decreasing trend during the focused period.
2022 Vol. 42 (11): 5036-5046 [Abstract] ( 521 ) [HTML 1KB] [ PDF 712KB] ( 2119 )
5047 Emission characteristics of carbonaceous components and water-soluble ions in PM2.5 from residential coal combustion
LI Peng, ZHOU Wei-qing, XU Qi-chun, NING Liang, WU Hua-cheng, ZHOU Zi-long, DING Li-ping
In this study, the characteristics of carbonaceous components and water-soluble ions in PM2.5 emitted from the combustion of 4typical residential coals were studied, and the effects of atmospheric aging (2d) on the content of carbonaceous components and water-soluble ions in PM2.5emitted from briquettes and bituminous coal were simulated by PAM-OFR (potential-aerosol-mass oxidation flow reactor). The results showed that bituminous coal had the highest content of carbonaceous components in PM2.5, reaching 57.96%, and its EC content was 4.3~9.6 times that of other residential coals. The water-soluble ions in PM2.5 emitted by residential coal combustion were mainly Na+ and SO42-, which accounted for 47%~76% of the total water-soluble ions. After the atmospheric aging, the content of NH4+ and NO3- ions in PM2.5 emitted from the combustion of briquettes and bituminous coal increased significantly, while the proportion of TC in PM2.5 decreased by 12.03% and 19.99%, respectively.
2022 Vol. 42 (11): 5047-5054 [Abstract] ( 216 ) [HTML 1KB] [ PDF 918KB] ( 1454 )
5055 Characteristics and influencing factors of microbial volatile organic compounds from a common indoor mold
WEN Sheng-chao, LIU Zhao-rong
Penicillium pinophilum was used as an example in this study and headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to collect and analyze microbial volatile organic compounds (MVOCs). The effects of the growth time, the temperature, the light and the oxygen content on the characteristics of MVOCs were investigated, and each contribution to indoor VOCs was discussed. A total of 6categories and 14 MVOCs were detected, including higher-concentration MVOCs such as ethanol, acetone, acetic acid, ethyl acetate, isoamyl alcohol and anisole, and lower-concentration MVOCs such as isobutanol, 2-methylbutanol, 2-Furanmethanol, toluene, m-xylene, 1-octene-3-ol, 3-octanol and limonene. The most obvious effects on MVOCs emission were the oxygen content and the growth time, which mainly affected the competitive metabolism of ethanol and acetone. The amounts of acetic acid and ethyl acetate were higher when the oxygen content was lower. There were considerable discrepancies of the types and the quantities of metabolites of Penicillium pinophilum along the growth time. The total amount of MVOCs reached maximum on the 4th~6th day of inoculation. Except acetic acid and limonene, other substances were obviously affected by the growth time. The maximum amount of MVOCs was produced at 25℃, and the minimum was at 35℃. The components of MVOCs were influenced by temperature. The light intensity had no obvious effect on the metabolism of Penicillium pinophilum. Under three experimental temperatures with certain oxygen content and light, the emission intensity of total MVOCs was between 5031and 7650ng/(m2×d), and the contribution of MVOCs concentrations to indoor air ranged from 0.0256 to 444.0380ng/m3.
2022 Vol. 42 (11): 5055-5062 [Abstract] ( 183 ) [HTML 1KB] [ PDF 728KB] ( 1159 )
5063 Low load running characteristics and NOx emission under low load for heavy-duty diesel vehicles
WANG Xiao-wei, JING Xiao-jun, GAO Tao, LI Gang, GU Xue-jing, ZHANG You-yuan
The operation and emission performances of a heavy-duty diesel urban vehicle which meets the China VI emission standard have been investigated based on remote monitoring data. Furthermore, a 6L diesel engine which also meets the China VI emission standard has been adopted to carry out the World Harmonized Transient-State Cycle (WHTC) and California Low Load Cycle (LLC) emission tests on an engine test bench using the engine-in-the-loop methodology. The NOx emission characteristics under the low-load conditions have been studied. Results suggest that the heavy-duty diesel urban vehicle tends to run under the low-load conditions, accompanied with a large portion of NOx emitted. The LLC test reveals the fact that the engine spends more time running under the low-load condition, which leads to a low emission temperature as well as low NOx conversion efficiency. The high NOx emission under the LLC test is mainly caused by the low exhaust temperature. China is suggested to develop low-load cycle to control the NOx emissions under such conditions according to the actual driving characteristics of commercial vehicles. The loading setting should be taken into consideration when developing the low-load cycle given the fact that the NOx conversion and emission are significantly affected by the vehicle loading.
2022 Vol. 42 (11): 5063-5071 [Abstract] ( 203 ) [HTML 1KB] [ PDF 537KB] ( 1127 )
5072 Preparation of oxygen vacancy-enriched CeO2 catalyst with hierarchical structure and its photocatalytic CO2 reduction performance
XU Zhong-zhen, JIA Ya-hui, GAO Dao-wei, ZHAO Wei, CHEN Guo-zhu
Oxygen vacancy-enriched CeO2 catalyst with hierarchical structure was synthesized by impregnation of Ce-BTC (BTC=benzene-1,3,5-tricarboxylic acid) into urea solution, followed by a calcination step. The as-prepared catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy (Raman) and ultraviolet visible diffuse reflection (DRS). The results showed that, different from the reported papers in which the g-C3N4 could be obtained by calcining urea impregnated metal organic frameworks (MOFs) at high temperature, while in this study, there was no g-C3N4 detected in Ce-BTC/urea system after calcination. The absence of g-C3N4 may be related to the MOF-derived CeO2 that inhibited the thermal polycondensation of urea-decomposed species, and prevented the formation of g-C3N4. However, the addition of urea into the Ce-BTC induced the oxygen vacancy change within the formed CeO2, and more importantly, Ce-BTC impregnated urea system developed into hierarchical structure after thermal treatment. When the as-prepared oxygen vacancy-enriched CeO2-5 catalyst with hierarchical structure was used for photocatalytic CO2 reduction, the yield of CO could reach 2.06μmol/g after 4hours, and the yield of CH4 was 1.42μmol/g, which was more than 7 times higher than that of CeO2 prepared by direct thermal decomposition of Ce-BTC.
2022 Vol. 42 (11): 5072-5079 [Abstract] ( 253 ) [HTML 1KB] [ PDF 1683KB] ( 4166 )
5080 Preparation of Tix-Ni1-x-MOFs and their selective catalytic reduction of NOx by CO
SHI Yong, LI Cheng, HUANG Lei, XIONG Wei, ZHAO Qi-dong, SUN Jiang-heng, DING Yue
Tix-Ni1-x-MOFs catalysts with different proportions were successfully synthesized by solvothermal method and microwave method, applied for selective catalytic reduction reaction of NOx with CO. The doping of Ti significantly improved NOx reduction performance of Ni-MOF catalysts and widened reaction temperature window. Ti0.2-Ni0.8-MOF showed the best denitration efficiency and reached 100% conversion in the temperature range of 200~400℃. Multiple characterizations were conducted to ascertain the properties of bimetallic Tix-Ni1-x-MOFs materials (e.g., TGA, XRD, SEM, FT-IR, XPS and BET). Ti-doping in Ni-MOF can improve the atomic dispersion, and indicate a strong metal-metal interaction between Ti and Ni which was conducive to produce more efficient Ni-O-Ti sites and oxygen vacancies, strengthen the Ni2++Ti4+ ↔ Ni3++Ti3+ redox cycle, and thus improve the catalytic performance of NO reduction reaction by CO. Compared with solvothermal method, the preparation of Ti0.2-Ni0.8-MOF by microwave method exhibits the advantages of high synthesis efficiency, good crystallinity, fine and uniform grains, which further enhancing its low-temperature denitration effect.
2022 Vol. 42 (11): 5080-5087 [Abstract] ( 210 ) [HTML 1KB] [ PDF 1563KB] ( 1156 )
Water Pollution Control
5088 Research on low-carbon operation mode in AAO-based wastewater treatment plants with low C/N influent
ZHOU Zheng, LI Huai-bo, WANG Yan, WANG Shuo, LI Ji
In order to clarify the carbon emission characteristics of wastewater treatment plants (WWTPs) with low C/N influent and to propose feasible low-carbon operation strategies, seven AAO-based WWTPs (divided into AAO-based WWTPs and AAO-MBR-based WWTPs) were operated for one year, and the carbon emissions based on the emission factor method were calculated and evaluated. In addition, according to the whole process analysis method, the carbon emission reduction pathways of WWTPs with significant low-carbon operation characteristics were subsequently analyzed. The results show that electricity consumption and nitrous oxide emissions are the main sources of carbon emissions, contributing 49.43% and 25.75% of carbon emissions on average, respectively. AAO-MBR-based WWTP is dominated by indirect carbon emissions, and electricity consumption accounts for about 60% of carbon emissions, while the direct carbon emissions caused by the microbial activity in AAO-based WWTP dominate. The average specific carbon emission of AAO-based WWTP was significantly lower than that of the AAO-MBR-based WWTP group (0.47 and 0.79kg CO2eq/m3), which presents remarkable low-carbon operation potential. Among the seven WWTPs, all the specific carbon emission evaluation indicators of WWTP7are the lowest, indicating that WWTP7has the highest potential for low-carbon operation. Furthermore, the study found that making full use of the influent carbon source, multi-path synergistic nitrogen and phosphorus removal, and precise control of dissolved oxygen to avoid over-aeration are the key points to greatly reduce energy consumption and achieve carbon emission reduction.
2022 Vol. 42 (11): 5088-5099 [Abstract] ( 360 ) [HTML 1KB] [ PDF 1177KB] ( 2688 )
5100 Parameter optimization of CANON granular-flocculate composite system with side-flow FNA suppression
REN Zhi-qiang, LI Dong, WANG Wen-qiang, ZHANG Jie
In order to explore the best combination of process parameters related to the strategy of inhibiting nitrite oxidizing bacteria (NOB) by side flow free nitrous acid (FNA) treatment, in the completely autotrophic nitrogen removal over nitrite (CANON) process of granular-flocculate composite system, batch test was used to explore the effects of sludge sedimentation time, FNA treatment concentration and FNA processing and processing time to the related functional bacteria activity influence. The NOB activity was targeted inhibition and treatment time on the activity of relevant functional bacteria, so as to inhibit the activity of NOB and reduce the effect of FNA on the activity of functional bacteria. The result showed that the settling time affected the activity of functional bacteria in the treated sludge. With the prolongation of the settling time, the activity of anaerobic ammonium oxidizing bacteria (AnAOB) in the discharged sludge gradually decreased. After settling for 1min, most of the discharged sludge was NOB, and retained as much AnAOB as possible in the reactor. At this time, the relative activities of AnAOB, ammonia oxidizing bacteria (AOB) and NOB were 15.79%, 54.55% and 68.63%, respectively. Considering the effect of FNA on the activity of NOB and AOB, the activity of AOB was 38.71%, while the NOB activity was only 12.5% after inhibition with 0.6mg/L FNA for 12h. The results of response surface analysis showed that the treatment time and treatment concentration of FNA were the key factors affecting the activity of NOB and AOB.
2022 Vol. 42 (11): 5100-5107 [Abstract] ( 206 ) [HTML 1KB] [ PDF 1020KB] ( 1280 )
5108 Treatment of thermal hydrolysis sludge digestion supernatant by PN/A-granular sludge process
ZHAO Dan, HAN Xiao-yu, ZHANG Shu-jun, HUANG Jing, JIAO Jia-tong, MAO Hua-xing, LU Zi-xin
An integrated PN/A denitrification treatment system was constructed with a mixture of anammox granular sludge and floc sludge. Efficient denitrification of sludge digestion supernatant pretreated with thermal hydrolysis was achieved through the optimization of operating parameters. By inoculating AnAOB biofilm sludge and ordinary activated sludge simultaneously and keeping a high FA (>20mg/L) and low aeration (DO£0.2mg/L), the partial nitrification and anammox reaction was rapidly initiated, and the nitrous accumulation rate got over 85% while the denitrification load reached 0.60kgN/(m3·d). The diluted digestion supernatant still had a certain inhibition on AnAOB activity, resulting in the total nitrogen load of the reactor decreased to less than 0.20kgN/(m3·d). However, the abundance of AnAOB in the system exhibited an overall increasing trend, indicating that the proliferation of AnAOB was not completely restrained. The average median diameter of the sludge mixture in the system increased slowly from 53μm to 109μm. Results of quantitative PCR and high-throughput sequencing showed that the treatment system enriched the AnAOB with a higher purity, the maximum abundance ratio could reach 8.06% with the dominant genus being Kuenenia. In addition, in the 93rd run cycle, the abundance ratio of Kuenenia in granular sludge was higher than that of AOB, which was 5.26%; while in the floc sludge, the abundance of Nitrosomonas for nitrification accounted for 1.64%, higher than that of AnAOB. This demonstrated the different spatial distribution characteristics of AOB and AnAOB abundance.
2022 Vol. 42 (11): 5108-5116 [Abstract] ( 206 ) [HTML 1KB] [ PDF 1107KB] ( 1473 )
5117 Structural stability and microbial response mechanism of aerobic granular sludge exposed to perfluorooctane sulfonate
XU Jia-jie, ZHANG Ni, XIE Zhou-yun, XU Yi-yi, TANG Li, XIA Jing-fen, YANG Guo-jing
The aerobic granular sludge that can tolerate perfluorooctane sulfonate (PFOS) was successfully cultivated in a lab-scale sequence batch reactor system. The tolerance mechanism of aerobic granular sludge to PFOS was discovered by examining the sludge characteristics, microbial communities, microbial phenotypes, and functional pathways in various domestication periods. In the presence of PFOS, the granular sludge maintained good stability through the disintegration, formation and maturation phases. PFOS reduced the filamentous bacteria, but promoted EPS secretion. The aforementioned phenomena were beneficial for the formation of compact structure of granules. During the whole domestication stage, a significant number of resistant bacteria and bacteria associated with the maintenance of granule stability emerged in granules, mainly including unclassified_f__ Comamonadaceae, Defluviicoccus, Dongia, Rhodoplanes, Flavobacterium, Thauera, Azospira, Azoarcus, Candidatus_ Competibacter, and norank_f__A4b, and there were significant positive correlations among some genera. In addition, the abundance of genes related to the quorum sensing pathway and the bacterial chemotaxis pathway up-regulated in the disintegration period, but returned to the initial level in the formation and maturation periods. It suggested that the bacterial quorum sensing system and chemotactic ability could play important roles in the process of granular stress. Therefore, aerobic granular sludge could tolerate PFOS in various ways such as positive response of specific bacterial communities, promotion of bacterial chemotaxis and quorum sensing, enhancement of EPS secretion, and enhancement of antioxidant stress capacity of the system. The application of EPS-based aerobic granular sludge, microbial agents, and signal molecules was conducive to the treatment of wastewater containing PFOS.
2022 Vol. 42 (11): 5117-5127 [Abstract] ( 249 ) [HTML 1KB] [ PDF 1915KB] ( 1751 )
5128 Influence of Fe3O4 on the anaerobic treatment system of saline wastewater
MA Kai-li, WANG Wei, LIU Yu-qing, YAN Meng-yi, CUI Yan-rui, KANG Wei, CAO Zhi-guo
The salinity was stepwise increased at fixed hydraulic retention time of 24h, two parallel anaerobic reactors with and without Fe3O4 were applied to investigate the influence of Fe3O4 on operational performance and sludge granulation of anaerobic system. The addition of Fe3O4 could effectively enhance the anaerobic treatment efficiency and ensure the stable operation at all tested salinity. The improvement of Fe3O4 on methane yield differed significantly at salinity varying from 0~2%. At salinity of 0, 0.5%, 1% and 2%, the methane yield of Fe3O4-supplemented reactor was 1.08, 1.36, 1.3 and 1.17-fold of the contrast reactor, the enhancement of Fe3O4 on methane yield was more significant under low salinity. In addition, the sludge properties and extracellular polymer substances secretion during the operation process were simultaneously analyzed as well. The results showed that the addition of Fe3O4 facilitated the formation of closely-packed anaerobic granular sludge, thus enhanced the anaerobic granulation process. According to the microbial community structure analysis, hydrogenotrophic methanogens were rapidly enriched with the increase of salinity, while the main bacterial consortium and metabolic pathways were changed as well. The effects of Fe3O4 on the microbial community structure and metabolic pathway of anaerobic system were also observed obviously distinct under low salinity (0.5%) and high salinity (1%, 2%).
2022 Vol. 42 (11): 5128-5135 [Abstract] ( 242 ) [HTML 1KB] [ PDF 992KB] ( 1148 )
5136 Preparation and autotrophic denitrification properties of embedded sulfur/iron biological filler
LIU Yan-fang, LIU Xiao-shuai, YIN Si-jie, GAO Wei, ZHANG Miao-yu, HAN Yan-he, LI Zai-xing
The embedded sulfur/iron biological filler (ESI Filler) was prepared by embedding and immobilization technology, and dynamic experimental research was carried out based on the upflow autotrophic denitrification reactor. By changing hydraulic retention time (HRT), pH, dissolved oxygen (DO) and other operating conditions, the denitrification performance and microbial community structure composition of ESI Filler reactor were explored. When the influent nitrate nitrogen (NO3--N) concentration was 30mg/L and the HRT was 10h, the NO3--N removal rate increased continuously to 99.80%. When the HRT was shortened to 2.5h, the removal rate of NO3--N decreased to about 61.35%. ESI Filler reactor had high stability to the changes of pH and DO, and the average removal rate of NO3--N could be maintained above 82.5%. However, the tolerance to low temperature was poor. When the temperature was reduced from 35℃ to 15℃, the average removal rate of NO3--N decreased from 90.12% to 68.80%. After running for 164days, the spheres did not break and scatter, showing a long service life. It was found by scanning electron microscopy that the surface of the filler was loose and porous, and a large number of rod-shaped bacteria were attached, which had become a good carrier of microorganisms. The results of high-throughput sequencing showed that the dominant bacterial genus in the embedded granules was the typical autotrophic denitrifying bacteria Thiobacillus, with an abundance of 80.79%.
2022 Vol. 42 (11): 5136-5143 [Abstract] ( 268 ) [HTML 1KB] [ PDF 838KB] ( 1645 )
5144 The EPS characteristics of Desulfovibrio desulfuricans sub sp. and its adsorption performance for Zn(Ⅱ) under exogenous sulfur induction
GAN Yu, SONG Wei-feng, YANG Zuo-yi, LIAN Ze-yang, MA Shuang-nian, HUANG Xiang-wu, YANG Ren-gao, WEN Yan-biao
In this paper, the effect of exogenous sulfur (Na2SO4, Na2SO3, Na2S2O3·5H2O) stress/induction on extracellular polymeric substances(EPS) of Desulfovibrio desulfuricans sub sp. (D. desulfuricans sp.) was studied. The results showed that addition of 0.50g/L Na2SO3 led to the highest EPS yield of 2104.39mg/g VSS (1888.52mg/g VSS of protein content), which was 300% higher than that without Na2SO3 addition, and as a result, 98.17% increase in Zn(II) adsorption capacity (954.4mg/g EPS) achieved. Three-dimensional fluorescence (3D-EEM) spectral results showed that tyrosine-like substances in EPS were greatly increased after sulfur stress/induction; Fourier transform infrared spectroscopy (FTIR) results showed that significant increases in functional groups such as —OH, C=O, C—O—C EPS were mainly responsible for the enhance adsorption of Zn(II); The results of X-ray photoelectron spectroscopy (XPS) results showed that the content of C—O/C—N, C=N and oxygen-containing functional group (X) in EPS increased after sulfur stress/induction (Na2SO3 and Na2S2O3·5H2O).
2022 Vol. 42 (11): 5144-5152 [Abstract] ( 204 ) [HTML 1KB] [ PDF 830KB] ( 1437 )
5153 Research progress on the mechanisms of iron-assisted anaerobic ammonia oxidation process
WANG Qian, HU Jia-yuan, LI Tian-hao, WANG Cai-xia, CHEN Jie, SHEN Yao-liang, LIU Wen-ru
How to promote the proliferation and metabolism of anammox bacteria, improve the nitrogen removal efficiency of anammox process, and ensure the long-term stable operation of the process are the hotspots of anammox research. Iron-assisted anammox is the most widely studied measure with high economical and practical potential. This paper briefly describes the iron-assisted anammox technology and its nitrogen removal performance. The mechanisms of iron-assisted anammox process in promoting anammox cells growth and enhancing systems nitrogen removal performance are summarized from the aspects of optimizing the habitats of anammox bacteria, stimulating the secretion of extracellular polymer, accelerating the accumulation of denitrification functional bacteria, inducing the evolution of cell microstructure, regulating the expression of key enzymes and functional genes, promoting signal molecular synthesis, and enhancing abiotic nitrogen removal. Finally, the iron-assisted anammox technology is summarized and prospected, and the concept of waste iron scrap-anammox process is proposed.
2022 Vol. 42 (11): 5153-5162 [Abstract] ( 240 ) [HTML 1KB] [ PDF 669KB] ( 2992 )
5163 A review of nano zero valent iron in water treatment
ZHANG Yong-xiang, DU Wei, LI Ya-jun, ZHAO Chong-hui
As one of the most commonly used nanoparticles, nano zero valent iron (nZVI) had been extensively studied in the removal of pollutants from environmental water. This review systematically and comprehensively summarized the related progress of nZVI, introduced various aspects of nZVI and then guided its development direction. Among them, the research contents mainly included preparation method, modification method, mechanism of action and catalytic mechanism for removing different pollutants in water, application in site research, and mechanism of toxicity. In this paper, it was found that there were still problems such as lack of comprehensive evaluation methods, limited application, and asynchronous research on nano zero valent iron. The future development of nZVI should have evaluation methods that consider reactivity, stability, mobility, and toxicity, to avoid the time difference of the same modified material in different research directions, so that the application of nZVI can be better applied to field research, and promote the application of nZVI in the field.
2022 Vol. 42 (11): 5163-5178 [Abstract] ( 344 ) [HTML 1KB] [ PDF 1006KB] ( 6492 )
5179 Inversion and identification of groundwater pollution sources based on SSA-BP and SSA
GE Yuan-bo, LU Wen-xi, BAI Yu-kun, PAN Zi-dong
The simulation-optimization method based on SSA-BP neural network alternative model and SSA were applied to study the inverse identification of groundwater pollution source location and release history. And the Cholesky decomposition method was applied to establish the continuous field of aquifer permeability coefficients in the groundwater flow model, which better describes the non-homogeneity of hydrogeological parameters compared with the common parameter partitioning method. The results showed that the SSA-BP neural network alternative model has a high approximation accuracy for the simulation model, and its average relative error is only 3.21%. The relative error of SSA in the inverse identification of source location is about 10%, and the relative error of SSA in the inverse identification of source intensity does not exceed 4%. Therefore, the proposed method is an effective groundwater pollution source identification method, which can provide reference for pollution responsibility identification and pollution remediation plan optimization.
2022 Vol. 42 (11): 5179-5187 [Abstract] ( 252 ) [HTML 1KB] [ PDF 1113KB] ( 1265 )
Solid Waste
5188 Changes in the structure of extracellular polymeric substances during sludge vermicomposting
CHEN Jin, XIE Jia-chen, XU Jun-jie, XIA Hui, HUANG Kui
Extracellular polymer substance (EPS) is an important factor affecting the stabilization of excess sludge. To reveal the relationship between EPS characteristics of sludge and its decomposition of vermicomposting, this study investigated the effect of vermicomposting on structural changes of sludge EPS, by comparing with the control treatment without earthworms. The results showed that the electric conductivity and nitrate nitrogen content of vermicompost significantly increased by 0.64 and 0.22 fold, respectively, compared with control treatment (P<0.05), suggesting that vermicomposting can significantly accelerate the mineralization rate of organic matter in sludge. In addition, total protein, and polysaccharide contents of EPS in each layer of vermicomposting decreased by 32.77% and 31.54% compared with control treatment, respectively. Fluorescence intensity of protein reduced more rapid in vermicompost than control, while humus of vermicompost remained at a higher level in later stages. Compared to control, the tryptophan contents in tightly-bound EPS (TB-EPS) and loosely-bound EPS (LB-EPS) in vermicompost decreased by 7.69% and 13.62%, respectively, while the humic acid content in LB-EPS and soluble EPS (SEPS) increased by 25.1% and 7.82%, respectively. The nitrate nitrogen content and electric conductivity during vermicomposting were significantly and positively correlated with DOC, protein, and polysaccharide contents in the structure of SEPS and LB-EPS (P<0.05), and their total DOC contents was significantly correlated with DOC and polysaccharide contents in each layer of EPS (P<0.05). However, only organic matter and DOC contents were significantly correlated with the polysaccharide contents of EPS layers in control during the experiment (P<0.05). The study indicated that earthworms could destroy the EPS structure of sludge to promote the decomposition of organic matter, thus accelerating the humification and stabilization process of vermicomposting, and the change of EPS structure of sludge could be a key indicator to assess the degree of sludge vermicomposting.
2022 Vol. 42 (11): 5188-5197 [Abstract] ( 229 ) [HTML 1KB] [ PDF 808KB] ( 1018 )
5198 Effect of pH on acid production by anaerobic fermentation of citric acid sludge and carbon source potential of fermentation broth
SUN Dong-xia, ZHOU Zi-an, FENG Zhi-he, HU Xiu-yu, QI Guang-xia, DONG Li-ming
The research of acid production by anaerobic fermentation with different pH control conditions was carried out for the treatment of waste activated sludge from citric acid wastewater, using anaerobic granular sludge of citric acid wastewater as inoculum. The mechanism of anaerobic acid production of citric acid sludge was evaluated by the analysis of volatile fatty acids (VFAs), organic matter, nitrogen and phosphorus contents and sludge dewatering performance. The results showed that the alkaline conditions with pH³10 were more conducive to the dissolution of organic matter to promote the production of VFAs. It was obvious that humic acid (HA) and fulvic acid (FA) at constant pH conditions would be dissolved in large quantities with Three-dimensional Excitation-Emission-Matrix Spectra analysis, thus reducing the yield of VFAs. The initial pH=10 was the optimum pH value for anaerobic acid production of citric acid sludge, and the VFAs concentration of (6681.47±126.82) mg COD/L for 4 days was the highest, which was nearly 2 times that of municipal sludge acid production reported in the literature, among which acetic acid was 49.8%. After fermentation, the relative abundances of acid-producing functional bacteria Chloroflexi and Bacteroidota increased from initial 9.52% and 10.87% to 16.84% and 14.39%, respectively. The normalized capillary suction time (nCST) value of the final sludge was (11.34±0.27) s·L/g with good dewatering performance, and the TP concentration of fermentation broth was (20.45±0.33) mg/L. Studies have shown that the alkaline anaerobic fermentation of citric acid waste activated sludge to produce acid fermentation broth has a good development potential as an exogenous carbon source in the sewage treatment process.
2022 Vol. 42 (11): 5198-5207 [Abstract] ( 290 ) [HTML 1KB] [ PDF 1574KB] ( 989 )
5208 Heat and mass transfer enhancement of sludge-based activated carbon and methanol working pair by in-situ impregnation of ferric-salt
GONG Xu-jin, WANG Jun-zhu, GUO Zi-rui, CHI Ri-guang
A new exploring research on transformation and utilization of municipal biological sludge was conducted in the present work, based on the interdisciplinary researches focusing on municipal engineering and cryogenic refrigeration engineering. In the previous studies, adsorption/desorption capacities of sludge-based activated carbon-methanol working pair was effectively improved based on pore structure regulation. However, the simultaneous improvement of heat and mass transfer deficiencies was still a bottleneck problem affecting the energy efficiency of sludge carbon adsorption refrigeration. Studies on heat and mass transfer enhancement of sludge-based activated carbon and methanol working pair by magnetic modification (in-situ impregnation of ferric-salt) were furtherly discussed. And post-impregnation modification was also conducted as comparative experiment. A novel in-situ magnetic modified sludge carbon IM-WNC and a post-magnetic modified carbon PM-WNC were prepared by response surface design optimization. The adsorption/desorption rate, adsorption isotherms, heat transfer performance of adsorption bed, refrigeration capacity and refrigeration power of methanol refrigerant were comprehensively compared. The results showed that the in-situ impregnation (IM-WNC) maintained higher total pore volume (0.6608cm3/g) and specific surface area (1122m2/g). Therefore, the heat transfer coefficient (600kg/m3, 4.586W/(m·K)) and the equilibrium adsorption capacity ((528.74±15.86)mg/g) were significantly improved. The maximum methanol adsorption capacity calculated by Langmuir isotherm model of IM-WNC reached up to (673.99±13.52) mg/g. The maximum temperature difference in center position of adsorption refrigeration bed of IM-WNC reached to 69.07℃ (adsorption-desorption cycle at 100℃/25℃). When the cycle time was 76min and desorption temperature was 100℃, the refrigeration capacity (RC) and refrigeration power (RP) of IM-WNC adsorption refrigerating bed reached to 501.43kJ/kg and 799.06kJ/(kg·h), respectively. And the increases of RC and RP reached to 15.61% and 18.69%, respectively, in comparison with PM-WNC.
2022 Vol. 42 (11): 5208-5219 [Abstract] ( 205 ) [HTML 1KB] [ PDF 1555KB] ( 778 )
5220 Overview and prospect of the application of ion exchange resin in treatment of sewage sludge
GENG Hui, XU Ying, DAI Xiao-hu, YANG Dian-hai
Ion exchange resins (IERs) have been widely used in wastewater treatment due to their insolubility and recyclability. There is still a lack of review on the application research in sludge. This paper summarized the common IERs used in sewage sludge (cation exchange resin, anion exchange resin and chelating resin), and introduced their basic characteristics and application direction. Among the IERs, cation exchange resin, especially strong acid styrene cation exchange resin, was the most widely used. The IERs were used in sludge for removal/recovery of heavy metals, recovery of phosphorus, extraction of extracellular polymer substances, and sludge conditioning. The fundamental mechanism, as well as the relevant advantages and disadvantages were demonstrated. Furthermore, in view of the deficiencies in the application of IERs in sludge, future research directions were proposed, including modifying or developing new IER to remove/recover heavy metals, optimizing the method for direct recovery of phosphorus, improving the mode of sludge conditioning, and developing new means of separation. This paper is beneficial for researchers to better understand the current application od IERs in sludge, to optimize the application of IERs, and to develop new IER for sludge treatment.
2022 Vol. 42 (11): 5220-5228 [Abstract] ( 361 ) [HTML 1KB] [ PDF 334KB] ( 1886 )
Soil Pollution Control
5229 Distribution, accumulation and sources of chromium in Hailuogou glacier retreated area
YANG Wen-qiang, ZENG Xi-wen, Lü Zhan, LIU Nan-tao, CHEN Pei-jia, WANG Xun, SHEN Hong, WANG Ding-yong
Given the complete succession sequence of glacier retreated area providing a novel platform to trace heavy metal cycles in the terrestrial ecosystems, we explored the distribution pattern, transportation and allocation among soil and vegetation components, and potential sources of chromium (Cr) at the Hailuogou, eastern of Tibetan Plateau. Cr concentration in C-horizon was (155.17±32.68) mg/kg, which was significantly higher than that in O-horizon (48.23±10.21) mg/kg (P<0.05). With the increase of retreated time, the concentration of Cr in O-horizon gradually decreased due to the increase of soil leaching induced the Cr lost. The dominant vegetation species in each succession stage had no obvious enrichment effect on Cr (ω<1). Moreover, the soil was the main Cr pool in the ecosystem of glacier retreated area (2269.90±234.57) mg/m2, whose Cr storage in the O-horizon of each stage up to 9~20times greater than that in vegetation. In the late period of succession, Cr storage in Oi-horizon and Oe-horizon gradually decreased but Cr storage of Oa-horizon and vegetation increased, because of the weak “return effect” of Cr, and increment of soil organic matter induced the enhanced Cr accumulation in organic soils. Moreover, we highlighted that the high cycling rate and low absorption-utilization efficiency was the main cycling strategy of Cr in Hailuogou glacier retreated area. The principal component analysis (PCA) results finally showed that Cr in soil of Gongga Mountain was mainly derived from weathering process of soil parent material (68.89%), but with the limited influence of atmospheric deposition.
2022 Vol. 42 (11): 5229-5238 [Abstract] ( 245 ) [HTML 1KB] [ PDF 1544KB] ( 1450 )
5239 Evaluation of heavy metal pollution in the soil surface of adaptive FCM——Taking the Nanjing refinery and its living area as an example
CHEN Hong-hua, WANG Lu, YU Ai-hua
Adaptive Fuzzy C-Mean Clustering (FCM) was used to excavate the pollution degree information of heavy metals in soil to achieve automatic acquisition of the classification of pollution degrees, in order to ensure the rationality of classification and truly reflect the spatial aggregation characteristics of heavy metal pollution. Taking the refinery and living area of Nanjing, Jiangsu Province as the research object, the heavy metal concentration values of Cr, Cd, Ni, Pb, Zn and Cu in the soil were collected. Firstly, the concentration values were analyzed by adaptive FCM, and then the spatial interpolation of geostatistical science was used to reveal the spatial agglomeration of pollution. The results indicated that there were different degrees of pollution in the study area; the degree of heavy metal pollution could be divided by the adaptive FCM algorithm more than the traditional clustering algorithm, the potential pollution information of the samples could be excavated, which could provide a reference for analyzing the causes of pollution and soil environmental remediation.
2022 Vol. 42 (11): 5239-5245 [Abstract] ( 237 ) [HTML 1KB] [ PDF 854KB] ( 1023 )
5246 Vertical distribution of background content of heavy metals and physicochemical parameters in soil of Shenzhen City
ZHAO Shu-hua, LUO Fei, XI Xiu-ping, YANG Kun, LIAO Man, ZHAO Yan, WU Jing-ya, LIN Ting
In order to find out the background content and vertical distribution of six conventional heavy metals (Cd, Hg, Cr, Cu, Zn and Ni), and to explore the relationship between the background content of heavy metals and the physicochemical parameters in different soil profile levels in Shenzhen, 50 typical soil profile sample points were laid out in the area of basic ecological control line, and 150 soil samples were collected at each point according to three layers A, B and C. The results showed that there were significant differences in the background contents of heavy metals in different sampling levels of soil profile. With the increase of depth, the background contents of Cr, Cu, Zn and Ni increased gradually, while Cd and Hg decreased first and then increased. The background contents of six heavy metals in Shenzhen soil profile were relatively low, which was slightly lower than the national soil environmental background values in the Seventh Five Year Plan. The physicochemical parameters of soil profile showed typical Southern soil characteristics. The pH values of soil were acidic. With the increased of depth, the soil bulk density, Al2O3and Fe2O3 contents increased gradually, while the contents of organic matter and CaO decreased gradually, and the cation exchange capacity increased first and then decreased; the characteristics of soil mechanical composition were that sand particles were the most, silt particles were the second, and clay particles were the least. The correlation between the background content of heavy metals and physicochemical parameters was analyzed, and it was found that Fe2O3, Al2O3 and soil mechanical composition had the most significant correlation with the background content of heavy metals in soil. The stepwise multiple linear regression analysis showed that the physicochemical parameters affecting the background content of heavy metals in soil were found to be Fe2O3, Al2O3, mechanical composition and cation exchange capacity.
2022 Vol. 42 (11): 5246-5254 [Abstract] ( 287 ) [HTML 1KB] [ PDF 969KB] ( 1004 )
5255 Ozone nanobubble enhanced surfactant repair diesel contaminated soil
PANG Zhong-zheng, ZHOU Hui-ping, YANG Song-nan, FENG Sheng
The experiment combined nanobubbles (diameter 50~270nm) with ozone, compared the improvement effect of ozone nanobubbles on the removal of diesel pollutants in soil by three surfactants. What is more, the influence of different treatments on pollutant removal rate, such as surfactant concentration, soil property and soil aging time, were also investigated. The soil samples treated in different ways were characterized by XRD and FTIR, as well as the degradation products of diesel components were analyzed by GC/MS. The results showed that under the same conditions, the elution efficiency of the three surfactants to diesel also increased with the increase of the concentration, and the elution capacity was SDS>SDBS>TX-100. The removal effect of the surfactant on the pollutants was significantly increased within 30minutes of the stirring experiment, and the growth rate slowed down between 30 and 40minutes. The removal rate of pollutants in sandy soil by ozone nanobubbles was significantly higher than that in loam soil, both the removal rate of diesel oil in sandy soil and loam soil increased by about 13% and 9%, respectively. The aging time of pollutants in the loam was inversely proportional to the removal rate but the ozone nanobubble treatment also significantly improved the diesel oil removal rate in the loam with a longer aging time, and increased by nearly 8% for the polluted loam aged for 60 days. The analysis of FTIR spectroscopy indicated that the surfactant containing ozone nanobubbles could reduce the effect on the main functional groups of organic matter in the soil. According to GC/MS spectrum showed that the residual pollutants were mainly alkanes, and the degradation difficulty order was alkanes
2022 Vol. 42 (11): 5255-5264 [Abstract] ( 235 ) [HTML 1KB] [ PDF 1128KB] ( 1489 )
5265 Characterization of contaminated construction sites in key regions
QIAO Fei, WANG Jin-guo, ZHENG Shi-yu, WEI Yun-bo, ZHUANG Chao, YANG Dong
In this paper, three key regions of industrial development in China were investigated(i.e., Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta regions), based on the 496contaminated sites included in the List of Soil Contamination Risk Control and Remediation of Construction Sites from 2018 to 2021. Statistical analysis was conducted on the regional distribution, soil-groundwater excess contamination characteristics, industry contamination correlation and geological conditions of the sites. The results showed that: The contaminated sites of Beijing-Tianjin-Hebei region were mainly located in Beijing-Tianjin and southern Hebei Province. The number of contaminated sites of Yangtze River Delta is the largest and the sites were widely distributed. The contaminated sites of Pearl River Delta is densely located in the Pearl River Estuary. Generally,soil contamination was dominated by the combined contamination of organic pollutants and heavy metals(48.43%), while groundwater was dominated by organic contamination(42.49%). High risk industries were chemical raw material and chemical manufacturing, metal smelting and rolling processing industry, with the risk load index greater than 0.25. The industry types of medium risk contaminated sites were plastics and rubber products industry, machinery manufacturing, metal products industry, electrical machinery and equipment manufacturing, and leather and fur manufacturing industry. The rest industry types of contaminated sites are low risk. The characteristics of the site soil-groundwater contamination were closely related to the historical industries. For example, the chemical raw materials and chemicals manufacturing industry, having the most diverse contaminations with halogenated hydrocarbons (12% of the total) and benzene (10.4% of the total), accounted for a heavier proportion than the rest of the industries. At the same time, heavy metal contamination in groundwater was serious in all industries, and conventional indicators such as ammonia nitrogen should also be noted. The maximum soil depth of exceedance for all types of typical contaminants was generally 0~5m at soil depth. The maximum soil depth of exceedance for heavy metals was greater than organic contamination. In terms of soil properties, the excess contamination was concentrated in low permeability layers such as clayey soils.
2022 Vol. 42 (11): 5265-5275 [Abstract] ( 316 ) [HTML 1KB] [ PDF 2432KB] ( 1447 )
5276 Potential risk assessment of cadmium pollution using hyperspectral remote sensing
WANG Dan-yu, WANG Wen, ZHAO Yan-yun
Cadmium (Cd), one of the major heavy metal pollutants in soil, is known to be hazardous and difficult to manage. An understanding of its quantitative spatial distribution characteristics in soil and the development of rapid monitoring methods are very helpful for ecosystem security and human health. This study utilised the Random Forest model to estimate the spatial distribution of potential Cd pollution risk levels in the Yangtze River basin, using soil Cd field data (2002~2015) collected from 10sites along the river basin and HSI hyperspectral remote sensing satellite data. The results showed that: (1) Using atomic standard spectral curve can greatly simplify the process of characteristic bands selection for Cd in soil; (2) Random Forest modelling is a good method for estimating the Cd content in soil at a high accuracy; (3) Cd pollution is widespread in the Yangtze River basin area. The majority of the study areas were found having more than 8% higher Cd in soil than the Chinese Environmental Quality Standard for Cd pollution, with the upstream area more serious than the rest of the basin. The main conclusions are: (1) It is feasible to use the standard spectral curve of Cd atoms for hyperspectral band selection for Cd risks inversion. A more accurate prediction model can be established through the selected characteristic bands. (2) The Random Forest modelling approach for large scale risk monitoring of Cd pollution in soil showed its credibility in most of the sampling areas in the Yangtze River basin except areas in the Qinghai-Tibet Plateau, especially in the Subtropical Monsoon Climate zone. (3) The Random Forest model prediction showed that Cd pollution exceeded the Environmental Quality Standard in all study areas, where most areas had a large portion of land surfaces at high risk levels. Along the river basin, the overall Cd pollution risk and the proportion of areas exceeding the standard in the upstream area is greater than that in the midstream and downstream areas. This finding agreed with the results of other studies. (4) The study showed that the surface Cd pollution in the upstream area is mainly caused by relatively abundant mineral resources and the backward and active of industrial activities, where in the midstream area is mainly due to the rapid industrial and economic development; and in the downstream area is related to agricultural cultivation, high population density and long history of human activities at a high pollution level.
2022 Vol. 42 (11): 5276-5284 [Abstract] ( 181 ) [HTML 1KB] [ PDF 1469KB] ( 934 )
5285 Research progress on biotic natural attenuation for the remediation of chlorinated hydrocarbon-contaminated sites
MA Xin-cheng, XU Hong-xia, SUN Yuan-yuan, SHI Xiao-Qing, WU Ji-chun
With the continuous development and the increasing maturity of Monitored Natural Attenuation (MNA), its application in the remediation of sites contaminated by chlorinated hydrocarbons is becoming more and more extensive in-depth. In this paper, we first conducted a brief review on the origin and development history of MNA. We then summarized contaminant, biological and environmental factors that affect the remediation efficiency of MNA, especially focusing on the biotic natural attenuation processes. Field monitoring and numerical simulation methods were also summarized to assess the natural attenuation capacity of contaminated sites. Afterwards, we analyzed development trend of the joint use of MNA and Enhanced Attenuation (EA) and discussed their current application status in laboratory studies and contaminated sites. To provide a reference for the green remediation of sites contaminated by chlorinated hydrocarbons, the natural attenuation characteristics of mixed pollutants, regulatory mechanism of biodegradation and the application of numerical simulation and isotope analysis should be further discussed.
2022 Vol. 42 (11): 5285-5298 [Abstract] ( 375 ) [HTML 1KB] [ PDF 571KB] ( 5181 )
Environmental Ecology
5299 Compositional and structural characteristics of DOM molecules in the overlying water of the Beiyun River
SUN Qing-xuan, ZHANG Li, YANG Jia-chun
FT-ICR-MS technology and analytical methods were used to comprehensively characterize the compositional and structural characteristics of DOM molecules in the overlying water of the Beiyun River, revealing the migration and transformation rules of DOM molecular composition and evaluating the potential environmental impact of DOM molecular composition. The results indicated that the DOM molecular compounds in the overlying water of the Beiyun River were mainly composed of lignin (63.19%) and proteins (12.96%). The stable DOM molecular formulas in the overlying water were mainly refractory lignin and basic metabolites and secretions that are continuously recycled and regenerated. The diversity of unique DOM molecular formulas correlated with intensity anthropogenic activities. The common DOM molecular formula that was preferentially transformed or degraded was mainly lignin with highly chemically active carboxyl and hydroxyl groups and liable lipids, proteins and carbohydrates. The Beiyun River had the characteristics of high input of exogenous wastewater, resulting in a large amount of liable DOM compounds in the overlying water, which increased the potential risk of river eutrophication.
2022 Vol. 42 (11): 5299-5307 [Abstract] ( 201 ) [HTML 1KB] [ PDF 782KB] ( 2087 )
5308 Distribution characteristics, source and ecological risks assessment of PAHs in water bodies of typical sections of the Yangtze River
YANG Meng-ru, XU Xiong, WANG Dong-hong, LIU Quan-zhen, Lü Jing, LIN Li-hua, WANG Dian-chang, CHEN Yong-bo, LIANG Wen-yan
Sixteen priority polycyclic aromatic hydrocarbons(PAHs) were investigated in water samples (wet, normal and dry periods) in the main stream of the Yangtze River using solid-phase extraction (SPE) -gas chromatography-mass spectrometry (GC-MS) analysis technique. The pollution levels and distribution characteristics of PAHs were studied, the sources and ecological risks of PAHs were evaluated based on quantitative analysis. The results showed that the concentration of Σ16PAHs was from 2.22 to 1450.91ng/L, the average concentrations of ΣPAHs was 107.04ng/L in the Yangtze River, among them, the concentration of Σ16PAHs in the Wuhan river section was the highest during the normal period, with an average value of 1050.64ng/L. Compared with other domestic water bodies in the past five years, the PAHs pollution in the main stream of the Yangtze River was at a moderately low level. In terms of spatial distribution, the Σ16PAHs in surface water of typical sections of the Yangtze River showed a trend of first rising and then falling from the Upstream Panzhihua section to the downstream Nanjing section, The variation trend of Σ16PAHs in temporal distribution: normal period (187.78ng/L)>wet period (73.30ng/L)> dry period (38.02ng/L). The analysis by isomeric ratio method showed that coal, biomass burning and petroleum sources were the main sources of PAHs in the main stream of the Yangtze River in dry and normal periods, In the wet season, PAHs mainly originated from coal and biomass combustion, among them, the sources of PAHs in the Nanjing River section were more complex. The ecological risk assessment of PAHs was carried out using the Species Sensitivity Distributions (SSD) assessment method. The results showed that the PAHs in the surface water of typical sections of the Yangtze River had not yet caused significant negative impacts on aquatic organisms. The comparison of the results with historical data showed that the current ecological risk of PAHs in the main stream of the Yangtze River is lower than the ecological risk before the implementation of the Yangtze River protection policy.
2022 Vol. 42 (11): 5308-5317 [Abstract] ( 308 ) [HTML 1KB] [ PDF 559KB] ( 1229 )
5318 Characteristics of phosphorus fractions in sediments and its influence on the water quality of Lake Nanyi
XIE Fa-zhi, LUO Kun, ZHU Yuan-rong, LI Hai-bin, LI Guo-lian, LIU Zhan, LI Wan-lu, CAI Ge-ge
Fractions of phosphorus (P) in sediments were investigated by using an improved sequential extraction procedure for inorganic P in 39 sampling sites from Lake Nanyi, Xuancheng city, Province of Anhui, China. The relationships between P fractions in sediments, concentrations of P in the overlying water and pore water were analyzed. Results show that the concentrations of total P (TP) in the overlying water of Lake Nanyi were in a high level, which were closely related with concentrations of TP in the pore water. Contents of TP in the sediments of Lake Nanyi ranged from 463.3 to 1016.6 mg/kg. Spatial distribution of P fractions in sediments was significant difference, which was closely related with the inputs of external P. Contents and their relative percentages were decreased in the order that calcium-bound P (Ca-P)>iron-bound P (Fe-P)>aluminium-bound P (Al-P)>reduced soluble P (RS-P)>residual P (Res-P)>loosely absorbed and dissolved P (L-P). Contents of TP in the sediments were significantly correlated with Fe-P, RS-P, Res-P and L-P. Input of external P and aquiculture was likely contributed large of internal Fe-P and RS-P in sediments from Lake Nanyi. The potential risk of internal load of P in sediments was high, which bioavailable P fractions including L-P, Al-P, Fe-P, and Rs-P accounted for 60% approximately. Concentrations of P in pore water were closely related with the spatial distribution characteristics of P fractions in sediments. The main compositions of P including Al-P and Ca-P have important influence on migration and transformation of P in the pore water. The zero equilibrium P concentration (EPC0) value of the sediments from the area of main river estuary ranged from 0.009 to 0.014 mg/L, which showed that the EPC0
2022 Vol. 42 (11): 5318-5327 [Abstract] ( 252 ) [HTML 1KB] [ PDF 821KB] ( 1600 )
5328 Antibiotics migration in surface runoff and leachate from purple soil
LIU Xin-yu, LIU Chen, TANG Xiang-yu, ZHANG Jian-qiang
This study aimed to investigate the concentration, flux and dynamics of several antibiotics via soil hydrological processes responding to continuous natural rainfalls. Field trials were carried out in a chicken-raising orchard of typical calcareous purple soil located in the hilly area of central Sichuan province. The results showed that a drastic increase of the antibiotic concentrations in the surface runoff and leachate could be led by continuous heavy rainfalls under a saturation excess mechanism. During the rainfalls, the antibiotic concentrations fluctuated consistently corresponding to the rainfall intensity, while the leachate responded with a time lag between 15~30minutes. The mean concentrations of sulfonamides reached up to 1.22 and 4.07μg/L in the surface runoff and leachate, respectively. Along with the soil preferential flow, the strongly adsorptive quinolones and tetracyclines were detected in the leachate even in the beginning of the rainfall. Leaching was an important path for antibiotic migration in the studied purple soil, as the total flux of leachate was two orders of magnitude higher than that of surface runoff. Furthermore, the concentration and flux of antibiotics for the chicken manure plots were significantly higher than that in the control plot, suggesting that the manure-derived substrate had accelerated the antibiotics transport. The variation of pH value and colloid concentration during rainfalls caused changes in ionic forms of the antibiotics and their binding with colloids, thus being the main factors affecting the migration. According to statistics, positive correlations were observed between the concentration of antibiotics and colloids. pH value showed significantly positive correlations with sulfonamides, tetracyclines and tylosin, while negative correlations were observed for florfenicol and quinolones.
2022 Vol. 42 (11): 5328-5340 [Abstract] ( 324 ) [HTML 1KB] [ PDF 2412KB] ( 889 )
5341 Spatial downscaling of chlorophyll A in Himawari-8 based on Landsat 8 images
XIONG Yuan-kang, FAN Dong-lin, HE Hong-chang, SHI Jin-ke, ZHANG Jie, XIAO Bin, FU Bo-lin
The chlorophyll-a products of the new geostationary meteorological satellite Himawari-8 are difficult to meet the requirements of water quality monitoring in near-shore waters with high spatial heterogeneity due to their low spatial resolution. To overcome this limitation, a non-linear random forest algorithm was used to improve the spatial resolution of the chlorophyll a data from Himawari-8 by constructing a downscaling model using the band reflectance data from Landsat 8and the chlorophyll-a products from Himawari-8. The results showed that the coefficients of determination (R2) of the two autumn models and two winter models reached 0.6, 0.72, 0.71 and 0.85, respectively, and the root mean square errors (RMSE) were 1.47, 1.05, 1.89, 0.76mg/m3, respectively. The comparative analysis of the measured site data showed that the chlorophyll-a data generated by the downscaled model had a high consistency with the chlorophyll-a data of Himawari-8, and the R2 reached 0.81 The spatial variation of chlorophyll-a concentration in the near-shore sea area is well reflected by the spatial variation of chlorophyll a data.
2022 Vol. 42 (11): 5341-5350 [Abstract] ( 274 ) [HTML 1KB] [ PDF 2018KB] ( 1140 )
5351 Occurrence and source of Per- and Polyfluoroalkyl Substances (PFASs) in seawater around oilfields in the Bohai Sea, China
LEI Ming, ZHANG Can, ZHOU Zhi-jie, WANG Xiao-meng, LIU Xiao-xing, Yang Wen-chao, CHENG Jia-yi, CHEN Hong
In order to study the pollution status of the PFASs (Per- and polyfluoroalkyl substances) near the offshore oil field area in China, in this study, concentrations of 19 legacy and novel PFASs in 92 seawater samples collected near the oilfields in Bohai Sea of China were measured. The total PFAS concentrations ranged from 9.33 to 113ng/L. As compared with other sea areas in China, the total concentrations of PFASs in the seawater around the Oilfields in the Bohai Sea were relatively high. Perfluorooctanoate (PFOA) was the predominant PFASs in most of the samples. Meanwhile, relatively high concentrations of hexafluoropropylene oxide dimer acid (HFPO-DA) were observed with a median concentration of 1.82ng/L, while 6:2 chlorinated polyfluorinated ether sulfonate (6:2Cl-PFESA) was not detected in all samples. Oilfields with high PFAS concentrations in surrounding seawater are located in the west of the Bohai Sea. The correlation analysis between the total PFASs concentrations and the offshore distance showed that the concentrations of the total PFASs in seawater near the oilfields in Bohai Sea were significantly correlated with the offshore distance, indicating that the land source was the main contributor of PFASs pollution in oilfields in Bohai Sea.
2022 Vol. 42 (11): 5351-5357 [Abstract] ( 265 ) [HTML 1KB] [ PDF 391KB] ( 1753 )
5358 Change and driving factors of vegetation coverage in the Yellow River Basin
WANG Xiao-lei, SHI Shou-hai, CHEN jiang-zhao-xia
The pixel binary model was used to inverse the fractional vegetation cover (FVC) from 1999 to 2019 based on the Google Earth Engine platform, and the unary linear regression analysis and the coefficient of variance method were used to study the changes in the FVC trend characteristics and stability. The geographic detector was used to analyze the driving force of vegetation change. The results showed that: (1) The FVC of the Yellow River Basin was generally low in the northwest and high in the Southeast; the medium-high and high-covered areas accounted for 21.74% and 17.87% of the study area, respectively; the FVC of the Yellow River Basin had improved well in the past two decades. The improvement of vegetation in the middle reaches of the basin was the most obvious, and the improvement area accounted for 48.52% of the total area in our study area; the stability of FVC was mainly stable. (2) The three driving factors of precipitation, sunshine duration, and relative humidity had the strongest influence on FVC in the Yellow River Basin. (3) Each driving factor had an interaction effect on the FVC. The two-factor enhancement or nonlinear enhancement was the main factor. The two-factor interaction enhanced the impact of the single factor. This study also revealed the most suitable range of factors that promoted vegetation growth. These results help to better understand the impact of natural and social factors on vegetation cover changes and their driving mechanisms.
2022 Vol. 42 (11): 5358-5368 [Abstract] ( 251 ) [HTML 1KB] [ PDF 2262KB] ( 818 )
5369 Effect of microplastics on the transport of environmental factors during icing and the mechanism of action
WANG Zhi-chao, DOU Ya-jiao, KANG Yan-qiu, ZHOU Xin, YANG Wen-huan, JING Shuang-yi, LI Wei-ping
In order to explore the influence of microplastics reserve on the distribution and migration of typical environmental factors (total nitrogen, total phosphorus, salinity, chemical oxygen demand and suspended solids) during the icing process, the indoor simulations were adopted to study the distribution and migration of typical environmental factors in the ice-water phase under different conditions (icing ratio, freezing temperature and mode and initial concentration). The migration ability of environmental was characterized by material distribution coefficient(K). The results showed that the ice had a repulsive effect on environmental factors during the freezing process, and the occurrence of microplastics under different conditions had a certain degree of influence on the distribution of environmental factors. The environmental factors that should have migrated to the water under the ice were partially retained in the ice due to the characteristics of microplastics, resulting in an increase in the concentration of environmental factors in the ice, which was 1.13~1.49 times that of the control group. At the same time, the concentration of environmental factors in the subglacial water decreased, which was 0.73~0.93 times that of the control group. The presence of microplastics also increased the partition coefficient K of environmental factors by 0.04~0.18 and decreased the ability of environmental factors to migrate to subglacial waters. However, the occurrence of microplastics did not change the trend of environmental factors transferring from ice to subglacial water during the freezing process. The carrying effect of microplastics on environmental factors was less than the repulsion effect of ice on environmental factors. At the same time, the influence of microplastics on the distribution and migration mechanism of environmental factors during freezing under different conditions could be explained from the perspective of crystallography and cocrystal theory.
2022 Vol. 42 (11): 5369-5377 [Abstract] ( 253 ) [HTML 1KB] [ PDF 2112KB] ( 943 )
5378 Effects of water table fluctuations and nitrogen concentration variations on the abundances of nitrogen-transforming functional genes in soil profiles
CUI Rong-yang, LIU Gang-cai, HU Wan-li, FU Bin, CHEN An-qiang
To explore the effects of nitrogen concentration in shallow groundwater and its water table fluctuations on the abundance of soil nitrogen-transforming functional genes, taking the undisturbed soil profile from cropland around Erhai as the object, changes in nitrogen concentrations and abundance of nitrogen-transforming functional genes in soil profiles under shallow groundwater table fluctuations (SND) and continuous flooding (SNF) with conventional nitrogen concentration, and shallow groundwater table fluctuations (0ND) without nitrogen were studied. The relationship between soil environmental factors and abundance of functional genes was discussed. The results indicated that, compared with the nitrogen concentrations in soil profile before the microcosmic experiment, the total dissolved nitrogen (TDN) concentrations in SNF, SND and 0ND decreased by 44%, 21% and 30%, and NO3−-N concentrations decreased by 55%, 28% and 38%, respectively. Meanwhile, compared with the abundance of nitrogen-transforming functional genes in soil profile in SND, the denitrification function gene abundances in 0ND and SNF decreased by 20% and 1%, while the anammox function gene abundances increased by 68% and 7%, and the nitrification function gene abundances decreased by 34% and increased by 23%, respectively. Changes in functional gene abundances were mainly driven by soil moisture content (MC), NH4+-N, NO3−-N and TDN. In conclusion, continuous flooding in soil profiles would significantly reduce dissolved nitrogen concentrations, and changes in alternation of drying-flooding and nitrogen concentrations in soil profile caused by the nitrogen concentrations in shallow groundwater and its water table fluctuations were the main drivers for changes in the abundance of nitrogen-transforming functional genes.
2022 Vol. 42 (11): 5378-5386 [Abstract] ( 306 ) [HTML 1KB] [ PDF 917KB] ( 1466 )
5387 Modified clay preparation via kaolin aluminum activation and its algae removal mechanism
WANG Ming-jiao, CAO Xi-hua, JIANG Kai-qin, JIANG Wen-bin, SONG Xiu-xian, YU Zhi-ming
This study analyzed modified clay (MC) prepared from calcined kaolin using a new method for activation of aluminum, which includes acid pickling, base neutralizing, supplementation of uncalcined kaolin clay, and aging. The algae removal efficiency (ARE) of MC was evaluated as a way to optimize various treatment conditions of the new method. Results showed that the acid pickling-base neutralization step had a significant impact on the ARE (P<0.05), achieving 90% of ARE when pH of the treated slurry calibrated to no more than 3.6 by base neutralization. Analysis of physicochemical properties of the MC and the examination of floc revealed that MC prepared with the optimized conditions had a compact curled sheet structure and a rough micro-surface, which exuded a large amount of activated aluminum from the mineral crystals, with higher contents of both the monomer aluminum (Ala) and the polyhydroxy aluminum (Alb) when MC was dispersed in seawater, suggesting that the activated aluminum was easily transformed into Ala and Alb. Meanwhile, the zeta potential of the suspended MC particles changed from negativity to positivity. As a consequence, the activated aluminum and the improved clay surface thus ensured that the MC has a higher capability to eliminate red tide algae.
2022 Vol. 42 (11): 5387-5394 [Abstract] ( 257 ) [HTML 1KB] [ PDF 685KB] ( 1306 )
5395 Research progress on bioaccumulation of per- and polyfluoroalkyl compounds by plants
HE Qiang, YAN Zheng, ZHI Yue, QIAN Shen-hua, WANG Xiao-ming, CHEN Yi, LIU Cai-hong, CHENG Cheng, HU Xue-bin
This review summarized the literature data, including bioaccumulation of 19 kinds of per- and polyfluoroalkyl compounds (PFAS) by 36 plants. Exposure, transport, and bioaccumulation feature data are summarized and interpreted; the mechanism of migration and accumulation of PFAS from environmental media to plant tissues was systematically elucidated; effects of PFAS molecular structure (such as perfluorocarbon chain length and head functional group), plant physiological characteristics, and environmental factors on the bioaccumulation process were discussed. In addition, future studies of phytoremediation and combined remediation of PFAS contaminated sites were prospected. The information can be used to manage and evaluate PFAS-contaminated sites, formulate phytoremediation plans, and assess ecological and health risk of PFAS contaminated sites.
2022 Vol. 42 (11): 5395-5407 [Abstract] ( 413 ) [HTML 1KB] [ PDF 955KB] ( 7165 )
Environmental Toxicology and Health
5408 Leaching behavior and ecotoxicity of chemical composition in polyvinyl chloride and rubber
LIU Jian-chao, HU Yong-rong
To investigate the leaching behavior and ecotoxicity of chemical composition in plastics, polyvinyl chloride (PVC) and rubber (CTR) widely existed in the environment were selected as the subjects of the study. Leaching potential of 25 organic plasticizers and 15 metals as the target substances were analyzed for PVC and CTR materials. The acute lethal effects and chronic sublethal effects (heart rate, thoracic limb activity and swimming activity) of Daphnia magna were used to characterize the ecotoxicological effects of PVC and CTR leachates. The results showed that 21 chemical compositions were detected in PVC and CTR leachates, with higher leaching concentrations of diisobutyl phthalate (DiBP), di (2-methoxy) ethyl phthalate (DMEP), bisphenol A (BPA), bisphenol F (BPF), Ca and Zn. The total concentrations of plasticizers and metals leached from CTR were 8.8 times and 1.2 times higher than those from PVC, respectively. The concentration of the new plasticizer BPF leached from CTR reached 3.51μg/g, which was significantly higher than that of BPA. Comparing the concentration of substances leached under different conditions, it was found that light can accelerate the release of DiBP, Zn and Ca from PVC and CTR, and their occurrence characteristics were affected by bacteria. Acute toxicity of CTR leachate to Daphnia magna is obvious, with the 48h-LC50 of 19.1% of the leaching solution. For chronic toxicity, the PVC leachate significantly inhibited the heart rate, thoracic limb activity and swimming activity of Daphnia magna, and caused body hypertrophy of Daphnia magna. The biological toxic effects caused by the continuous discharge of PVC and CTR in the aquatic environment should not be ignored.
2022 Vol. 42 (11): 5408-5417 [Abstract] ( 230 ) [HTML 1KB] [ PDF 985KB] ( 1298 )
5418 Health risk assessment of exposure to multiple pollutants in Guangzhou
HUANG Lin, LIU Di, CAI Dong-jie, CHEN Su-juan, DONG Hang, LIN Guo-zhen, WANG Bo-guang, YANG Jun
This study attempted to use the Bayesian kernel machine regression (BKMR) to analyze the health effects of multiple air pollutants (i.e, SO2、NO2、PM10、PM2.5、CO and O3) on non-accidental mortality in Guangzhou during 2015~2018. We found that all the pollutants presented significant effects on non-accidental mortality. The absolute values of effect estimates associated with the change in SO2, O3 or NO2 concentration from the 25th percentile to the 75th percentile gradually increased with the increment of the fixed percentile of other pollutants; On the contrary, the absolute values of effect estimates decreased gradually when the concentration of PM2.5, CO or PM10 changes from the 25th percentile to the 75th percentile. The cumulative effect estimates associated with exposure to multiple pollutants on non-accidental mortality at lag 0~1 day was positive. Compared with the lowest concentration, when the concentration of all pollutants increased to the 90th percentile, the number of non-accidental deaths will increase by 21.98% (95% CI: 3.04%, 44.41%). With the application of BKMR model, this study found that exposure to multiple pollutants could produce a combined impact on public health in Guangzhou. In terms of air pollution prevention and control, it is necessary to not only target the main local air pollutants, but also strengthen the policies on protecting the public from exposure to multi-pollutants.
2022 Vol. 42 (11): 5418-5426 [Abstract] ( 460 ) [HTML 1KB] [ PDF 1374KB] ( 2204 )
5427 A study on employees’ skin exposure to polycyclic aromatic hydrocarbons and health risk in a petrochemical industrial park
GUO Jian, LUO Xiao-jun, GUAN Ke-lan, Lü Yin-zhi, ZENG Yan-hong, MAI Bi-xian
In the study, skin wipe samples were collected from four typical skin parts (forehead, palm, forearm and shank) of 30 volunteers (15 men and 15 women), who work in a Petrochemical Industrial Park in Maoming City (a typical petrochemical city). The concentrations of 15 polycyclic aromatic hydrocarbons (∑15 PAHs) in wiping samples were determined by gas chromatography-mass spectrometry (GC-MS), and the human exposure doses through skin exposure and hand-mouth contact were calculated. The concentration of Σ15PAHs in skin samples ranged from 21 to 1.9×104ng/m2. The PAH concentrations exhibited significant differences among different skin parts (P<0.01) with the order of forehead>palm>forearm>shank. PAHs are mainly composed of 3~4rings. Although no statistical difference was observed in ∑15 PAHs between female and male, the daily dermal absorption doses of PAH (DADderm) was significantly higher in female [41ng/(kg×d)] than male [28ng/(kg×d)]. The hand-mouth exposure dose [0.34ng/(kg×d)] was negligible to compare with the dermal absorption dose [34ng/(kg×d)]. The bared skins contribute to 88% of dermal absorption dose. There was no obvious non-carcinogenic risk but risks of skin cancer were higher than the acceptable level (1×10-4) for 7% staff, indicating potential skin cancer risk.
2022 Vol. 42 (11): 5427-5435 [Abstract] ( 270 ) [HTML 1KB] [ PDF 764KB] ( 1466 )
Environmental Impact Assessment and Management
5436 Enterprises emission reduction effect of the "Eleventh Five-Year Plan" obligatory pollution control
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Relying on the implementation of the "Eleventh Five-Year" obligatory pollution control in 2006, based on the matching database of Chinese industrial enterprise data and enterprise pollution emission data, this paper analyzed the effect and mechanism of the implementation of total control and obligatory environmental regulation policy on enterprise emission reduction. Results suggested that the pollution emissions of SO2 and COD of enterprises with high regulatory intensity decreased by 12.8% and 12.1% respectively after the implementation of obligatory pollution control, and the effect remained significant after a series of robustness tests. Mechanism analysis showed that after the implementation of obligatory pollution control, clean energy consumptions and technical efficiency of SO2 group increased by 0.12% and 53.56% respectively; while for COD group, clean energy consumptions and technical efficiency increased by 0.14% and 56.60% respectively. Emissions of enterprises indeed decreased via the the change of energy consumption structure and the improvement of technical efficiency. Heterogeneity analysis showed that there were significant differences in emission reduction effects between state-owned enterprises and non-state-owned enterprises, large-scale enterprises and small-scale enterprises, heavy pollution industry enterprises and non-heavy pollution industry enterprises, as well as enterprises in the eastern and western regions. There was a local negative correlation between enterprises' distance to geographical boundary and the enterprises pollution emissions.
2022 Vol. 42 (11): 5436-5446 [Abstract] ( 215 ) [HTML 1KB] [ PDF 543KB] ( 1427 )
5447 Effects of river basin horizontal ecological compensation on water environment benefits
HU Dong-bin, LIN Mei, CHEN Xiao-hong
Based on the panel data of 26 prefecture-level cities in Zhejiang and Anhui provinces from 2000 to 2019, this paper uses the synthetic control method to quantitatively analyze the overall and structural impacts of the three-round horizontal ecological compensation pilots’ policy on the Xin'an River basin on its water environmental benefits. The results showed that: (1) there existed temporal heterogeneity in policy effects. The first and second rounds of policy pilots significantly improved the overall water environment of the Xin'an River Basin, while the third round of pilots had a negative impact on the upstream water environment. (2) there existed spatial heterogeneity in policy effects. The horizontal ecological compensation policy of the river basin increased the biodiversity value of the downstream by an average of 6.8 million yuan, but reduced the biodiversity value of the upstream by an average of 1.5 million yuan. (3) there existed structural heterogeneity in policy effects. Structural decomposition of water environmental benefits showed that the horizontal ecological compensation policy increased the value of water purification capacity in the Xin'an River Basin by an average of 3.1874 billion yuan, but reduced the value of its product supply by an average of 1.3402 billion yuan. (4) there existed expected benefits in policy effects. The effect of the horizontal ecological compensation policy has appeared two years ahead the official implementation of the policy.
2022 Vol. 42 (11): 5447-5456 [Abstract] ( 306 ) [HTML 1KB] [ PDF 699KB] ( 1225 )
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