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2013 Vol.33 Issue.7,Published 2013-07-20
1153 Size distribution of atmospheric particle number in Beijing and association with meteorological conditions
LANG Feng-Ling, YAN Wei-Qi, ZHANG Quan, CAO Jun
From November, 2011 to August, 2012, measurements of size distribution of particle number had been conducted using WPS (Wide Particle Spectrometer, Model 1000XP) in Beijing, and main meteorological parameters such as temperature, relative humidity, wind speed and direction were collected simultaneously. The results indicated that during the monitoring period, the average total number concentration of particles between 10 nm and 10 μm was 25014 cm-3, and it was 31007 cm-3 in winter, 23152 cm-3 in spring, and 20882 cm-3 in summer, respectively. Most of the number size distribution exhibited in single-peak pattern or two-peak pattern. The highest particle number concentration was observed in winter. Seasonal variations in different modes also could be found. The particle number concentration and size distribution were significantly influenced by meteorological parameters, especially by wind speed. With the increase in wind speed, the Aitken mode and accumulation mode particle number concentrations decreased, while nucleation mode particle number concentrations increased. The particle number concentration of nucleation mode and Aitken mode reached the peak value at three intervals: rush hour in early morning, noon with the strongest solar radiation, and night with lower temperature inversion layer. By comparison, the particle number concentration of accumulation mode varied slightly and increased at night.
2013 Vol. 33 (7): 1153-1159 [Abstract] ( 412 ) [HTML 1KB] [ PDF 881KB] ( 2027 )
1160 Pollution characteristics and influencing factors of organic and elemental carbon in PM2.1 in Nanjing
WU Meng-Long, GUO Zhao-Bing, LIU Feng-Ling, LU Xia, LIU Jie, REN Yu-Rui
The concentrations of organic carbon (OC) and elemental carbon (EC) in aerosol fine particles (PM2.1) collected in Nanjing Normal University representing urban area and in Nanjing College of Chemical Technology standing for suburban industrial area were analyzed using DRI Model 2001A Thermal Optical Carbon Analyzer. The pollution characteristics of OC and EC in the two sites were evaluated, and the sources of carbonaceous materials in PM2.1 were analyzed. The results showed that the annual average concentrations of OC and EC were 12.79μg/m3 and 3.18μg/m3 respectively in urban area, and 12.79μg/m3 and 3.18μg/m3 respectively in suburban industrial area, indicating that pollution in industrial area was more serious than in urban area. The concentrations of OC and EC in winter and spring were obviously higher compared with those in summer, either for urban area or for suburban industrial area, which was the same as the case of correlation between OC and EC. The higher concentrations of OC and EC in winter and spring were resulted from the increased coal combustion and the unfavorable transport conditions of air pollutants affected by inland west wind in Nanjing. However, in summer, some air pollutants could be diluted and removed via frequent rainfall and typhoon. For the urban and suburban areas, the ratio of second organic carbon (SOC) in total organic carbon (TOC), estimated by OC/EC ratio method, were 46.63% and 45.65% respectively, which was the highest in summer among the four seasons. This implies that high temperature and strong radiation were benefical to SOC generation through photochemical reaction.
2013 Vol. 33 (7): 1160-1166 [Abstract] ( 267 ) [HTML 1KB] [ PDF 383KB] ( 1003 )
1167 Daily variation of atmospheric aerosol number concentrations at the foot of Mount Huangshan
CHEN Xiao-Xiao, JIN Lian-Ji, ZHU Jing-Min
The number concentrations for atmospheric aerosol and its daily variation were discussed by the data collected with a Wide-Range Particle Spectrometer (WPS) (manufactured by MSP. Ltc.) at the foot of Mount Huangshan (Zhaixi) from May to September, 2011. Obvious diurnal variation for atmospheric aerosol number concentrations was found in sunny days. The total aerosol number concentrations exhibited peak values at 6:00, 12:00 and 18:00. Human activities, turbulence and the mountain-valley wind were the main reasons for the daily variation. Excepted for the pollution periods mainly raised by traffic emission, the average total aerosol number concentrations decreased by 319 per cubic centimeter, and the decreased percentage for the daily average aerosol number concentrations was 12.17%. For particles within the size ranges of 0.01~0.02 μm,0.02~0.05 μm,0.05~0.1 μm,0.1~0.5 μm,0.5~1.0 μm,1.0~2.5 μm, their number concentrations decreased by 31.32%, 20.29%, 6.59%, 7.49%, 1.23%, 2.51%, respectively. It indicated that traffic emission mainly influenced the concentrations of particles in the size of 0.01~0.5 μm,which occupied 25.81%.
2013 Vol. 33 (7): 1167-1173 [Abstract] ( 222 ) [HTML 1KB] [ PDF 492KB] ( 692 )
1174 Nutrients of atmospheric wet deposition from the Qianliyan Island of the Yellow Sea
HAN Li-Jun, ZHU Yu-Mei, LIU Su-Mei, ZHANG Jing, LI Rui-Huan
Rainwater samples were collected at the Qianliyan Island of the Yellow Sea for the period of 2009-2010 and analysed for pH and nutrient concentrations (i.e. NH4+, NO3- + NO2-, SiO32- and PO43-). The results showed that the pH values in 58% samples ranged from 5.6 to 7.0, dominated by neutral depositions. Concentrations of nutrients had seasonal variations, higher in spring and winter but relatively low in summer and autumn. Based on comparison of inorganic nitrogen concentrations in rainwater at different regions, the air-mass back-trajectory and annual variations, atmospheric wet depositions over the Yellow Sea were affected by the anthropogenic emissions as well as sand-dust storms. Furthermore, the historical overview of existing data indicated that atmospheric dry and wet depositions of NH4+-N, DI(NO3- + NO2-), SiO32--Si and PO43--P account for 87%, 47%, 3% and 53%, respectively, of total terrestrial (i.e. atmospheric depositions and riverine influx) input. Rainfall in this region can dramatically increase surface water nutrient level that enhance the primary productivity.
2013 Vol. 33 (7): 1174-1184 [Abstract] ( 274 ) [HTML 1KB] [ PDF 783KB] ( 758 )
1185 Influence of typical weather conditions on the airborne particulate matters in urban forests in northern China
GUO 二Guo, WANG Cheng, QIE Guang-Fa, CAI Yu
It is important to understand the effects of weather conditions on the flux and transportation of airborne particulate matters for assessing the role of urban forests may play in controlling those pollutants in the air. The daily concentration variation of airborne particulate matters with four diameters were measured under typical seasonal weather conditions throughout the year in urban forests with different structures located in the West Mountain of Beijing, China. Our objectives were to explore the influence of typical weather conditions on the concentration changes of airborne particulate matters in urban forests with different structures in four different seasons of the year. The results showed that: 1) the rainfall reduced the concentrations of coarser particulate matters as the total suspended particulate (TSP) concentration was only 0.58~0.68 of that measured on the days with clear sky conditions. The ratios of finer particulate matters in TSP increased in the clear daytime after rains. On the contrary, the concentrations of airborne particulate matters increased in the nighttime after rain due to the increased air humidity; 2) snowfall decreased the concentrations of airborne particulate matters. After snow the concentrations of airborne particulate matters of four diameters were only 0.2 of that measured over the days under clear sky conditions; 3) cloud and fog aggravated the pollution of airborne particulate matter, especially at night. Moreover, increased amplitudes of finer particulate matters were larger in foggy and cloudy days; 4) the concentrations of finer airborne particulate matters and their ratios in TSP were increased under high humidity, stable,and muggy “sauna” weather conditions in summer;5) wind reduced the concentrations of airborne particulate matters after rain to some degree. In contrast, the concentrations of airborne particulate matters was increased by wind under dry air conditions, specifically in cloudy days after wind;6) the concentrations of airborne particulate matters were higher in exposed deciduous forests in windy spring and winter, while they were higher in forest with higher canopy density in foggy and sauna days in summer and autumn.
2013 Vol. 33 (7): 1185-1198 [Abstract] ( 228 ) [HTML 1KB] [ PDF 1015KB] ( 959 )
1199 Lead emission and speciation of coal-fired power plants in China
DENG Shuang, ZHANG Fan, LIU Yu, SHI Ying-Jie, WANG Hong-Mei, ZHANG Chen, WANG Xiang-Feng, CAO Qing
A full-scale field study of lead (Pb) emission from coal combustion was conducted at six coal-fired power plants in China. Flue gas samples were taken from the inlets and outlets of the existing air pollutant control devices (APCDs) to investigate their effects on speciation and distribution of Pb in the flue gas. Concurrent with flue gas sampling, coal, bottom ash, fly ash and samples from the FGD process (desulfurization gypsum and waster water) were collected. Average release of Pb from the pulverized-coal (PC) boilers was 97.11% of Pb in feed coal. In comparison, the release of Pb from a fluidized bed furnace was lower, at 84.99%. A high proportion of Pb (86%~92%) was found as particulate-bound Pb (Pbp) in the flue gas at outlet of boiler. Further, there was a positive correlation between the proportion of particulate-bound Pb (Pbp) and the chlorine content in the coal. The existing APCDs were able to remove most of the Pb in the flue gas, dedusting devices being most effective. Around 91.85% of Pb in flue gas was removed by electrostatic precipitator (ESP), while Bag-house filters captured 95.12%. The Pb removal efficiency of wet flue gas desulfurization (FGD) varied from 35.67 to 77.81%, which depended on the process operation. The result of overall lead (Pb) balance showed that 81.97%~90.18% of Pb in feed-coals was discharged with fly ash, while 3.94%~11.82% of Pb was discharged with the desulfurization gypsum. Only 1.75%~5.40% was emitted directly into the atmosphere.
2013 Vol. 33 (7): 1199-1206 [Abstract] ( 221 ) [HTML 1KB] [ PDF 560KB] ( 939 )
1207 Concentrations and profiles of PCDD/Fs in ambient air around a municipal solid waste incinerator
ZHANG Zhen-Quan, ZHANG Man-Wen, ZHAO Bao-Wei, ZHANG Su-Kun, REN Ming-Zhong
The concentrations and profiles of PCDD/Fs in ambient air around a municipal solid waste incinerator (MSWI) in an industrial area were obtained. The concentrations of 2,3,7,8-PCDD/Fs of the 14 ambient air sampling sites were in the range of 1.74~15.2 pg/m3 (0.156~1.44pg I-TEQ/m3), with an average value of 4.60 pg/m3(0.426pg I-TEQ/m3), and the levels of 3 sampling sites were higher than the ambient air standard of 0.6 pg TEQ m-3 for dioxins proposed by Japan, which demonstrated that the PCDD/Fs concentrations around the MSWI in some area in this study were a bit high. And the highest concentration of 2,3,7,8-PCDD/Fs was found at a downwind location, 1.3km away from the MSWI, which was consisted with the result of the maximum ground concentration calculated by AERMOD models. 1,2,3,4,6,7,8-HpCDF and OCDD were the dominated PCDD/Fs in all the samples, while 2,3,4,7,8-PeCDF was the dominated congener contributed to the total toxicity equivalent (TEQ). The homologue profiles of PCDD/Fs in some ambient air locations were similar to those in the flue gas of the MSWI, indicating the possibility of influence by the source, while the profiles of other sites differed with them with a significantly higher TCDD contribution. Principal component analysis (PCA) results revealed that the concentrations of PCDD/Fs in ambient air in some areas were obviously affected by the MSWI, which was coincided with the fingerprint analysis. Dioxin inhalation exposure dose estimation results showed that the dioxin inhalation exposure risk of the population living in the study areas was still at a relative safe level.
2013 Vol. 33 (7): 1207-1214 [Abstract] ( 218 ) [HTML 1KB] [ PDF 647KB] ( 829 )
1215 An optimization model for regional complex air pollution control
FANG Die, QIAN Yue-Dong, WANG Qin-Geng, DUAN Ning
Regional complex air pollution is one of the main environmental problems in China. In order to find economic and effective control strategy on the problem, an optimization model was developed in this study. Compared with existing models of the same kind, this model had following new features:(1)Both direct and secondary pollutants were involved;(2)The synergetic effect was considered for a control measure that could remove multi-pollutants; (3) Environmental targets were set in terms of “gap closure”; (4)Soft constraints were established by introducing slack variables. Being subject to constraints of multi-factor environmental targets, economical and technological conditions, as well as management requirements, the model searches for an optimal strategy of pollution control strategy with the minimum cost. A case study suggested that the model was rational and feasible to be put into practice.
2013 Vol. 33 (7): 1215-1222 [Abstract] ( 205 ) [HTML 1KB] [ PDF 496KB] ( 920 )
1222 Observational experiment and numerical simulation of air pollutant dispersion in Yuzhong
SHAO Yi, ZHANG Shu-Wen, ZUO Hong-Chao, DONG Wen-Cheng
Based on the data from the field experiments in Yuzhong city of Gansu Province in China, flow field and tracer gas dispersion were simulated by using a CFD model Fluent. Firstly, a 3-dimensional urban building model was created by using the Gambit software according to the measured data, and then inputted into the Fluent model for computation. Comparison of the simulated wind and pollutant dispersion with the observed data showed that the simulated results were reasonable. The total similarity coefficient of wind direction and speed between simulated and observed data were 0.876 and 0.843, respectively, and the correlation coefficient of pollutant between simulated and observed data on the plane 0.5m and 27m above the ground level were 0.71 and 0.72, respectively. Therefore, the fluent model can be used for studying urban pollutant dispersion, and guiding the setup of air quality monitoring station based the simulated results.
2013 Vol. 33 (7): 1222-1230 [Abstract] ( 241 ) [HTML 1KB] [ PDF 2137KB] ( 959 )
1231 Removal of toluene by mixed surfactant aqueous solutions
HE Lu-Hong, LIU Hua-Yan, LU Han-Feng, ZHANG Ze-Kai, CHEN Yin-Fei
The improvements of sodium dodecyl benzene sulfonate (SDBS) and sodium chloride to aqueous solution of Tween-20 were studied, which were used to absorb toluene, a representative of volatile organic compounds (VOCs) from the industrial plants. The toluene removal efficiency and critical micelle concentration (CMC) were measured for the aqueous solutions of Tween-20, Tween-20/SDBS and Tween-20/SDBS/sodium chloride, respectively. The toluene removal efficiency was improved significantly when the surfactant concentration reached above CMC. With the addition of SDBS and sodium chloride into the Tween-20 aqueous solution, the CMC was reduced, but the toluene removal efficiency increased. Under the air flow of 300 mL/min, the spray flow rate of 75 mL/min, the inlet toluene concentration of 800 mg/m3, the operation temperature of 30℃ and the surfactant concentration of 1CMC, the toluene removal efficiencies were 56%, 70% and 77% with Tween-20, Tween-20/SDBS (1/4) and Tween-20/SDBS /sodium chloride (1/4/0.1) aqueous solution as absorbent, respectively. The ternary combined surfactant aqueous solution exhibited the optimum absorption effect which could reduce the dosage of surfactant and save the operation cost of the VOC removal process.
2013 Vol. 33 (7): 1231-1236 [Abstract] ( 245 ) [HTML 1KB] [ PDF 403KB] ( 1051 )
1237 Effect of anaerobic/aerobic alternative operating strategy on the formation of granular sludge in a sequencing batch reactor
WU Chang-Yong, ZHOU Yue-Xi
The periodic existence of feast and famine phases induced by cyclic feeding is generally believed to be beneficial to the formation of aerobic granules in SBR system. In order to enhance this feast-famine regime, we run a lab-scale SBR in anaerobic/aerobic mode. There were granular sludge on the 7d after the SBR started up, and on the 30d the granular sludge system was stable. During the initial granulation period, the content of extracellular protein (PN) was 6mg/(g-VSS), which was lower than that of the famine phase(10mg/g-VSS), while it was higher during the granular stabilization period, 13mg/g-VSS and 20mg/g-VSS, respectively. It was interesting to find that the changing trend of extracellular polysaccharides (PS) at the feast and famine period was opposite to that of the PN. And during the whole operation period, the amount of PS was increased from 13mg/g-VSS to 55mg/g-VSS. In addition, it was higher at the end of feast phase than that of the famine phase. That is, the PS and PN play a different role in the granulation process, and PN seems to be more important to the initial granulation stage. Aerobic granulation was initiated by the feast/famine regime in the SBR system.
2013 Vol. 33 (7): 1237-1243 [Abstract] ( 306 ) [HTML 1KB] [ PDF 485KB] ( 1004 )
1244 Optimization on wet oxidation process of papermaking black liquor with uniform design method
ZHANG Yong-Li, WANG Cheng-Zhi, WEI Chao-Hai, SHANG Ling-Ling
Papermaking black liquor was treated in WAO process with uniform design method. The regression equations on CODCr, absorbance and turbidity were obtained by data regressions, and each regression equation was significant; Oxygen partial pressure showed the greatest impact on each indicator of papermaking black liquor. In the WAO reaction process, reaction temperature, oxygen partial pressure, influent pH value, influent concentration, stirring intensity and reaction time were researched, and the optimized six factors operating conditions were ordinally 180℃, 3.0MPa, 7.25, 5500mg/L, 500r/min, 60min. In these optimized operating conditions, for the papermaking black liquor, CODCr and CODCr removal rate were respectively 1661mg/L and 69.8%, and the absorbance and decolorization rate were respectively 0.63 and 96.3%, and the turbidity and turbidity removal rate were respectively 661NTU and 74.8%. Uniform design method got a better application in papermaking black liquor teeatment with WAO method.
2013 Vol. 33 (7): 1244-1251 [Abstract] ( 232 ) [HTML 1KB] [ PDF 369KB] ( 631 )
1252 The basic theoretical exploration of regional ecology
GAO Ji-Xi
The regional ecological issues, which are triggered by the global economic integration, regional development integration and ecological service transfer，have been attracting more and more people’s attention, and have a direct impact on regional sustainable development. Developing a systematic subject on handling regional ecological issues becomes urgent. In this paper, we try to set up the theoretical framework of regional ecology in aspect of subject development based on ecology, geology, economy and other relevant subjects. Ecology is the subject which studies regional ecological structure, process, function as well as the integration and interaction mechanism of regional ecological elements; ecological medium is the link and key element between the ecological regions. According to the components of the ecosystems and current human activities, the most important ecological medium affecting the region include wind, water and resource, which form three kinds of ecological regions-basin, wind field and resource cycle respectively. The main study area and key issues of regional ecology include regional ecological structure, process, function; regional ecological integrity and differentiation rules; regional ecological evolvement rules and driving forces; regional ecological carrying capacity and suitability; regional ecological link and ecological assets transfer; regional eco-compensation and environmental profits sharing mechanism.
2013 Vol. 33 (7): 1252-1262 [Abstract] ( 224 ) [HTML 1KB] [ PDF 758KB] ( 1043 )
1263 Distribution and source identification of polycyclic aromatic hydrocarbon of surface sediments from the center part of South Yellow Sea, China
ZHANG Sheng-Yin, LI Shuang-Lin, DONG He-Ping, ZHAO Qing-Fang, SHI Ji-An, ZHANG Zhong-Ning
The 49 surface samples collected from the center part of South Yellow Sea were analyzed for total organic carbon (TOC), particle size, polycyclic aromatic hydrocarbons (PAHs) and methyl phenanthrene. The concentrations of all of 14 PAHs (ΣPAHs) were 81.63 to 6567.31 ng/g dry weight, and the concentrations of anthropogenic PAHs (ΣEPA PAHs) were 29.2 to 1029.1 ng/g, with an average of 255.1 ng/g, suggesting medium-low level pollution in studying area. The less correlations among ΣEPA PAHs, TOC and medium diameter (MD) indicates that atmospheric deposition or leakage of ship-borne petroleum may be main enrichment methods of pollution, comparing with fluvial transport. The concentrations of perylene relative to the penta-aromatic isomers are dominant, with 6.40%~88.85% of ΣPAHs, and the low concentrations of perylene were related by anthropogenic activity, while the high concentrations indicating diagenetic terrestrial origin. The characteristics of high weight compounds, isomers analysis and methyl phenanthrene revealed that the anthropogenic PAHs were mainly derived from combustion or incomplete combustion of coal and higher plants, however, some samples showed obvious petroleum features also confirm the existence of PAHs derived from leakage of petroleum fuel and crude oil.
2013 Vol. 33 (7): 1263-1270 [Abstract] ( 199 ) [HTML 1KB] [ PDF 571KB] ( 826 )
1271 Influences of environmental governance project on spatial distribution of phosphorus in Lihu Lake
ZHANG Bo, LI Yong-Feng, JIANG Xia, WANG Shu-Hang, HU Jia-Chen
In order to evaluate the impact of the water environment governance project on the water quality in Lihu Lake, this paper studied on the spatial distribution of phosphorus and its influencing factors by an investigation in the Lihu Lake in April, 2012. The results showed that the TP contents in the water ranged from 0.03 to 0.31mg/L with the mean value of 0.06 mg/L, and increased from the west to the east. At the same time, TP in the estuaries was higher than that in the lake. The spatial distribution of TP in the sediments was similar to that in the water. The TP in the sediments in the lake ranged from 321.77 to 1062.08mg/kg with the mean value of 593.75mg/kg, the TP in the estuaries ranged from 523.38 to 1396.39 mg/kg with the mean value of 784.51mg/kg. The long-term monitoring data of water showed that the water quality had been substantially improved by a series of water treatment projects, the annual average of TP in water fell from 0.18mg/L down to 0.06mg/L after governance project. However, due to the internal loading of phosphorus the eutrophication is still the mean problems we are facing. Furthermore, the correlation analysis indicated that the diffusion flux of phosphorus was positively correlated with the TP and the exchangeable phosphorus in the sediments.
2013 Vol. 33 (7): 1271-1279 [Abstract] ( 172 ) [HTML 1KB] [ PDF 1049KB] ( 656 )
1280 Development and application of IBI based on fish to assess the river’s health in the East Tiaoxi River
HUANG Liang-Liang, WU Zhi-Qiang, JIANG Ke, ZUO Teng-Chen-Lang, LU Ye-Xiong-Yi, LI Jian-Hua
Index of biological integrity (IBI) based on fish to assess the river health in the East Tiaoxi River was established in this study. Two IBI systems and assessment criteria were established due to sampling sites being from two different eco-regions. The sampling sites from the tributaries in the upper reaches of East Tiaoxi were in the eco-zone of evergreen broad-leaf forest between Zhejiang Province and Fujian Province, and IBI in the tributaries was established including species richness (M1), percentage of species in the Balitoridae to species richness (M5), percentage of endemic species to species richness (M6), Shannon-Wiener’s diversity index (M7), percentage of invertivores to abundance (M13), percentage of herbivores to abundance (M14) and percentage of intolerant species to abundance (M16). The sampling sites from the middle-lower reaches of East Tiaoxi River were in the Eco-zone of agriculture area in urban and suburban in the Yangtze River Delta, and IBI in the middle-lower reaches was established including species richness (M1), percentage of species in the Gobiidae to species richness (M4), percentage of endemic species to species richness (M6), Shannon-Wiener’s diversity index (M7), percentage of species inhabit in the up layer to species richness (M8), percentage of species inhabit in the middle-up layer to species richness (M9), percentage of herbivores to abundance (M14), percentage of species spawn in shells to species richness (M21), abundance (M22) and percentage of DELT to abundance (M23).The status of river health was categorized into five levels, such as ‘healthy’, ‘fair’, ‘poor’, ‘very poor’ and ‘no fish’. Two IBIs were applied to assess the 45 observation sites in the East Tiaoxi River in 2010 and 2011. The results showed that the river’s health was mainly at the status of ‘fair’ and ‘poor’. By contrast in 2011, the observation sites of ‘healthy’ and ‘fair’ decreased by 1 and 2 sites than those in 2010, respectively. Meanwhile, the observation sites of ‘poor’, ‘very poor’ and ‘no fish’ increased by 1 site than those in 2010, respectively.
2013 Vol. 33 (7): 1280-1289 [Abstract] ( 272 ) [HTML 1KB] [ PDF 773KB] ( 686 )
1290 The Effect of nutrition status on sediments distribution characteristics of total mercury and methylmercury in Lake Taihu
REN Jia-Ying, JIANG Xia, CHEN Chun-Xiao, ZHANG Wan-Zhong, ZHANG Yong-Sheng, YI Feng-Jiao, ZHAO Zheng
In order to investigate the effects of nutritional status on the mercury (Hg) distribution and methylation of mercury (Hg) in the sediment in Lake Taihu, total mercury (THg) and methylmercury (MeHg) were determined by PSA and GC-CVAFS for sediment samples collected from areas with different levels of trophic level. The organic matter content in sediment, total nitrogen (TN) and total phosphorus (TP) in overlying water were also measured. The results showed that the average concentration of THg in surface sediment was 62.94ng/g with a range from 32.30 to 150.28ng/g, correlating well with trophic levels. The vertical profile of THg was influenced by anthropogenic activities and organic matter. MeHg concentrations in the sediment ranged from 0.32 to 1.01ng/g with an average of 0.51ng/g. There were no significant differences among MeHg levels in the bay areas with different trophic status. The concerntration of MeHg was affected by organic matter content, with higher levels of MeHg being observed in surface sediment and decreasing with increasing depth until reaching a stable level. The methylation ratio of Hg was low in Lake Taihu, probably due to high dissolved oxygen in water that inhibits methylation process.
2013 Vol. 33 (7): 1290-1297 [Abstract] ( 255 ) [HTML 1KB] [ PDF 437KB] ( 814 )
1298 Candidatus Accumulibacter metabolic activity and population structure in MUCT process treating domestic wastewater with nitritation and denitrifying phosphorus removal
ZENG Wei, LI Bo-Xiao, WANG Xiang-Dong, BAI Xin-Long, PENG Yong-Zhen
Nitritation and denitrifying phosphorus (P) removal was achieved in Modified University of Cape Town (MUCT) process treating domestic wastewater with a low C/N ratio. The effect of nitrite accumulation on performance of phosphorus removal and population structure of “Candidatus Accumulibacter” was investigated during nitritation establishment and destruction. Results indicated that P removal was mainly completed by denitrifying P removal of about 88%. The P removal efficiency had a clear correlation with the nitrite accumulation rate. Under nitritation, the P removal was 30% higher than that under complete nitrification, suggesting that nitrite was appropriate to be used as electron acceptor for denitrifying P removal when treating low C/N wastewater. Real time quantitative PCR assays were carried out using poly-P kinase 1 (ppk1) as phylogenetic marker to characterize the abundance of total Accumulibacter and the relative distributions and abundances of the Accumulibacter clades. Under complete nitrification, a very few Acc-I clade below 5% in total Accumulibacter was present using nitrate as electron acceptor. When the reactor transformed into nitritation, Acc-I clade gradually disappeared. The Acc-IID clade using nitrite as electron acceptor for denitrifying P removal was always the dominant Accumulibacter throughout the operational period, with above 92% on average in total Accumulibacter, even up to nearly 100%, which led to stable performance of denitrifying P removal using nitrite as electron acceptor. The nitrite concentrations significantly affected the abundances of Acc-IID clade.
2013 Vol. 33 (7): 1298-1308 [Abstract] ( 371 ) [HTML 1KB] [ PDF 1015KB] ( 793 )
1309 Isolation and identification of an efficiently heterotrophic nitrifier, and its removal characterization of ammonia nitrogen
WU Jian-Jiang, WANG Zhao-Yang, XU Pei-Ya
A heterotrophic nitrifying bacteria isolated from the activated sludge of landfill leachate through the enrichment medium with sodium succinate as the sole carbon source was identified by its morphologic observation and the analysis of physiological characteristics and 16S rDNA sequence; its nitrifying function and removal characterization of ammonia nitrogen were also studied in this paper. This strain was identified as Pseudomonas sp., named as XS76 with JQ934897 as its GenBank accession number. After 24h-cultivation, nearly 60% ammonia nitrogen was converted into intracellular nitrogen and 35% removed. There was only a small amount of nitrate nitrogen accumulation, but with no accumulation of hydroxylamine and nitrite nitrogen. The factors including carbon source, organic nitrogen, C/N and cultivation temperature were important for the removal of ammonia nitrogen. The optimum condition for heterotrophic nitrification was as follows: sodium succinate as the carbon source, ammonium sulfate as its nitrogen source, C/N ratio of 15, shaking speed of 180~200r/min, pH of 6~9, culture temperature of 34℃ and the initial ammonia nitrogen of 420 mg/L. After 96h-cultivation under the optimum condition, the removal rate of ammonia nitrogen reached 99.20% high. Hence, XS76 could have high potential in practical wastewater treatment.
2013 Vol. 33 (7): 1309-1315 [Abstract] ( 238 ) [HTML 1KB] [ PDF 606KB] ( 1138 )
1316 Dietary exposure and risk assessment of nonylphenol and octylphenol from the Shenzhen total diet
LIU Chun-Hong, WANG Wei-Hua, CHU Yue, ZHANG Jin-Zhou, LAI Yu-Ting, SUN Yuan-Ming, HUANG Wei
To assess dietary exposure to nonylphenol (NP) and octylphenol (OP) for Shenzhen population. The exposure assessment was carried out based on the diet survey and representative food samples from Shenzhen total diet study. 853 residents from 244 households in Shenzhen were selected through multi-stage randomized cluster sampling. Food consumption data was collected by three 24-h recalls and weighting and recording method. High performance liquid chromatography-mass/mass (HPLC-MS/MS) with solid-phase extraction, liquid-liquid extraction method was established for determination of NP and OP in food samples. Risk index was used for estimating the human exposure risk. The total daily amount of NP intake from the foods in urban area, suburban area and the whole city were 89.7,128.9,116.2ng/(kg×bw) respectively. The total daily amount of OP intake was 42.7ng/(kg×bw) for urban area, 35.3ng/(kg×bw) for suburban area and 39.3 ng/(kg×bw) for the whole city. For risk assessment, the risk indexes of NP for the residents of urban and suburban area and the whole city were 0.02, 0.03 and 0.02 respectively, while the indexes of OP for the three were all 0.0004. NP exposure was higher than OP in Shenzhen population, but the risk indexes for the two were lower than 1. Thus, the amount of NP and OP intakes through the total diet were found to be at a relatively safe level.
2013 Vol. 33 (7): 1316-1322 [Abstract] ( 232 ) [HTML 1KB] [ PDF 431KB] ( 844 )
1323 Oxidative damage of pesticide cypermethrin on mouse brain cells and the antioxidant role of vitamin E
MA Ping, ZHANG Zhong-Jie, JIAO Ming, DAN Shi-Gang, WU Yang, CHEN Jiao-E, YANG Xu
Kunming mice were randomly grouped into six groups and orally administered with drugs daily for a week; the groups included one solvent control group, three cypermethrin groups, one high dose cypermethrin plus vitamin E protection group and one vitamin E group. The exposure doses of cypermethrin groups were 10, 20and 40mg/kg respectively. Some brain tissues were then made into homogenates for the measurement of ROS (reactive oxygen species), GSH (glutathione) and MDA (Malondialdehyde) contents. Meanwhile, DPC (DNA-protein Crosslink) coefficients were detected from brain cell suspension. The brain contents of ROS, MDA and DPC coefficients increased gradually in a dose-dependent manner, whereas GSH content decreased accordingly. In the exposure group with the dose of 20mg/kg, ROS(841.3±100.34), GSH contents[(12.54±1.316)nmol/L] and DPC coefficients(0.054±0.004) were significantly higher than those of the control group (P<0.05); In the highest dose group (40mg/kg), GSH content [(10.51±1.545)nmol/L]was significantly higher than that of the control group (P<0.05), the significance of differences of ROS(1014.3±81.67)、MDA contents[(2.849±0.218)μmol/L] and DPC coefficients(0.079±0.005) to the control group have all become extreme (P<0.01). However, compared to the high cypermethrin dose group, high dose cypermethrin plus vitamin E protection group had lower ROS(719.5±74.56 )(P<0.05), MDA[(1.662±0.265)μmol/L] (P<0.01) and DPC coefficients(0.055±0.005) (P<0.05) levels, and higher GSH contents[(16.52±1.985)nmol/L](P<0.05). Cyermethrin at certain doses (320mg/kg) can induce oxidative stress in mice brain, whereas vitamin E has antioxidant effects.
2013 Vol. 33 (7): 1323-1327 [Abstract] ( 235 ) [HTML 1KB] [ PDF 340KB] ( 673 )
1328 Toxicity of organic silicon adjuvant Breakthru S240 to Daphnia magna
LI Xiu-Huan, MIAO Jian-Qiang, LI Hua, MU Wei, LIU Feng
In order to evaluate the safety of the organic silicon adjuvant Breakthru S240 on Daphnia magna, this study investigated the acute toxicity, chronic toxicity and embryo toxicity, according to the commendatory standard test method namely experimental guideline for environmental safety evaluation of chemical pesticide. The 48h-LC50 value of the organic silicon adjuvant to D. magna was 1.218 mg/L, which belongs to the medium toxicity. The 21day chronic toxicity test showed that, the organic silicon adjuvant could significantly affect the breeding, length and sex differentiation, and the efficiency was more evident with the increase of concentration. The impact was not obvious for the growth and of F1(1st) after F0 being exposed to the organic silicon adjuvant. But it still showed significant differences for reproduction of F1(3rd) compared with the control group. It maybe have relationship with the exposed time. In addition, the organic silicon adjuvant had potential hazard to the development of embryo of D. magna and the inhibition rate reached to 68.50%.
2013 Vol. 33 (7): 1328-1334 [Abstract] ( 267 ) [HTML 1KB] [ PDF 427KB] ( 643 )
1335 Optimization of best management practices for non-point source pollution in Danjiangkou Reservoir Basin
WANG Xiao, HAO Fang-Hua, ZHANG Xuan
SWAT model was utilized to simulate the results of Best Management Practices (BMPs) for non-point source (NPS) pollution in Dangjiangkou Reservoir basin. Cost, change of cultivated land area and reduction of non-point source pollution load of each BMP as well as the pollution reduction was taken into consideration when conducting the management practices optimization in different slope-degree zones. Multiple attribute decision making based on information entropy was applied to optimizing BMPs. Crop residual cover, contour ploughing and no-tillage were suggested to be conducted in region with slope degree less than 5°. In the zone with slope degree from 5° to 15°, terrace was demonstrated to be the most effective practice. This research also stated that hedgerows was firstly suggested to conducted in 15°~25° zone, while crop residual cover was another prior practice in this area. Conversion of cropland to forest had superiority as the best management practice in >25° area. This research provided decision making support for BMPS for NPS pollution reduction in Danjiangkou Reservoir basin.
2013 Vol. 33 (7): 1335-1343 [Abstract] ( 503 ) [HTML 1KB] [ PDF 549KB] ( 15869 )
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