Most Cited  The most cited articles published since 2010, extracted from Scopus.
Air quality management in China: Issues, challenges, and options
Shuxiao Wang | Jiming Hao
Volume 24, Issue 1, January 2012, Pages 2-13
This article analyzed the control progress and current status of air quality, identified the major air pollution issues and challenges in future, proposed the long-term air pollution control targets, and suggested the options for better air quality in China. With the continuing growth of economy in the next 10-15 years, China will face a more severe situation of energy consumption, electricity generation and vehicle population leading to increase in multiple pollutant emissions. Controlling regional air pollution especially fine particles and ozone, as well as lowering carbon emissions from fossil fuel consumption will be a big challenge for the country. To protect public health and the eco-system, the ambient air quality in all Chinese cities shall attain the national ambient air quality standards (NAAQS) and ambient air quality guideline values set by the World Health Organization (WHO). To achieve the air quality targets, the emissions of SO 2, NOx, PM 10, and volatile organic compounds (VOC) should decrease by 60%, 40%, 50%, and 40%, respectively, on the basis of that in 2005. A comprehensive control policy focusing on multiple pollutants and emission sources at both the local and regional levels was proposed to mitigate the regional air pollution issue in China. The options include development of clean energy resources, promotion of clean and efficient coal use, enhancement of vehicle pollution control, implementation of synchronous control of multiple pollutants including SO 2, NOx, VOC, and PM emissions, joint prevention and control of regional air pollution, and application of climate friendly air pollution control measures. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Spatial distribution and pollution assessment of heavy metals in urban soils from southwest China
Guanghui Guo | Fengchang Wu | Fazhi Xie | Ruiqing Zhang
Volume 24, Issue 3, March 2012, Pages 410-418
To identify the concentrations and sources of heavy metals, and to assess soil environmental quality, 63 soil samples were collected in Yibin City, Sichuan Province, China. Mean concentrations of As, Pb, Zn, and Cu were 10.55, 61.23, 138.88 and 56.35 mg/kg, respectively. As concentrations were comparable to background values, while Pb, Zn, and Cu concentrations were higher than their corresponding background values. Industrial areas exhibited the highest concentrations of As, Pb, Zn, and Cu, while the lowest concentrations occurred in parks. Statistical analysis was performed and two cluster groups of metals were identified with Pb, Zn, and Cu in one group and As in the other. Spatial distribution maps indicated that Pb, Zn, and Cu were mainly controlled by anthropogenic activities, whereas As could be mainly accounted for by soil parent materials. Pollution index values of As, Pb, Zn, and Cu varied in the range of 0.24-1.93, 0.66-7.24, 0.42-4.19, and 0.62-5.25, with mean values of 0.86, 1.98, 1.61, and 1.78, respectively. The integrated pollution index (IPI) values of these metals varied from 0.82 to 3.54, with a mean of 1.6 and more than 90% of soil samples were moderately or highly contaminated with heavy metals. The spatial distribution of IPI showed that newer urban areas displayed relatively lower heavy metal contamination in comparison with older urban areas. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Application potential of carbon nanotubes in water treatment: A review
Xitong Liu | Mengshu Wang | Shujuan Zhang | Bingcai Pan
Volume 25, Issue 7, July 2013, Pages 1263-1280
Water treatment is the key to coping with the conflict between people's increasing demand for water and the world-wide water shortage. Owing to their unique and tunable structural, physical, and chemical properties, carbon nanotubes (CNTs) have exhibited great potentials in water treatment. This review makes an attempt to provide an overview of potential solutions to various environmental challenges by using CNTs as adsorbents, catalysts or catalyst support, membranes, and electrodes. The merits of incorporating CNT to conventional water-treatment material are emphasized, and the remaining challenges are discussed. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Concentration and source identification of polycyclic aromatic hydrocarbons and phthalic acid esters in the surface water of the Yangtze River Delta, China
Lifei Zhang | Liang Dong | Lijun Ren | Shuangxin Shi | Li Zhou | Ting Zhang | Yeru Huang
Volume 24, Issue 2, February 2012, Pages 335-342
The pollution from polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in the surface water of the rapidly urbanized Yangtze River Delta region was investigated. Fourteen surface water samples were collected in June 2010. Water samples were liquid-liquid extracted using methylene chloride and analyzed by gas chromatography-mass spectrometry. Concentrations of PAHs and PAEs ranged 12.9-638.1 ng/L and 61-28550 ng/L, respectively. Fluoranthene, naphthalene, pyrene, phenanthrene, di-2-ethylhexyl phthalate, and di-n-butyl phthalate were the most abundant compounds in the samples. The water samples were moderately polluted with benzo[a]pyrene according to China's environmental quality standard for surface water. The two highest concentrations of PAHs and PAEs occurred in samples from Taihu Lake, Wuxi City and the western section of Yangchenghu Lake. Potential sources of pollution at S7 were petroleum combustion and the plastics industry, and at Yangchenghu Lake were petroleum combustion and domestic waste. Pollution in samples from the Beijing-Hangzhou Grand Canal originated from diesel engines. There were no obvious sources of pollution for the other water samples. These results can be used as reference levels for future monitoring programs of pollution from PAHs and PAEs. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Mercury removal from coal combustion flue gas by modified fly ash
Wenqing Xu | Hairui Wang | Tingyu Zhu | Junyan Kuang | Pengfei Jing
Volume 25, Issue 2, February 2013, Pages 393-398
Fly ash is a potential alternative to activated carbon for mercury adsorption. The effects of physicochemical properties on the mercury adsorption performance of three fly ash samples were investigated. X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, and other methods were used to characterize the samples. Results indicate that mercury adsorption on fly ash is primarily physisorption and chemisorption. High specific surface areas and small pore diameters are beneficial to efficient mercury removal. Incompletely burned carbon is also an important factor for the improvement of mercury removal efficiency, in particular. The C-M bond, which is formed by the reaction of C and Ti, Si and other elements, may improve mercury oxidation. The samples modified with CuBr2, CuCl2 and FeCl3 showed excellent performance for Hg removal, because the chlorine in metal chlorides acts as an oxidant that promotes the conversion of elemental mercury (Hg0) into its oxidized form (Hg2+). Cu2+ and Fe3+ can also promote Hg0 oxidation as catalysts. HCl and O2 promote the adsorption of Hg by modified fly ash, whereas SO2 inhibits the Hg adsorption because of competitive adsorption for active sites. Fly ash samples modified with CuBr2, CuCl2 and FeCl3 are therefore promising materials for controlling mercury emissions. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Health risk assessment of heavy metals in soils and vegetables from wastewater irrigated area, Beijing-Tianjin city cluster, China
Yanchun Wang | Min Qiao | Yunxia Liu | Yongguan Zhu
Volume 24, Issue 4, April 2012, Pages 690-698
The possible health risks of heavy metals contamination to local population through food chain were evaluated in Beijing and Tianjin city cluster, China, where have a long history of sewage irrigation. The transfer factors (TF) for heavy metals from soil to vegetables for six elements including Cu, Zn, Pb, Cr, As and Cd were calculated and the pollution load indexes (PLI) were also assessed. Results indicate that only Cd exceeded the maximum acceptable limit in these sites. So far, the heavy metal concentrations in soils and vegetables were all below the permissible limits set by the Ministry of Environmental Protection of China and World Health Organization. The transfer factors of six heavy metals showed the trend as Cd > Zn > Cu > Pb > As > Cr, which were dependent on the vegetable species. The estimated dietary intakes of Cu, Zn, Pb, Cr, As and Cd were far below the tolerable limits and the target hazard quotient (THQ) values were less than 1, which suggested that the health risks of heavy metals exposure through consuming vegetables were generally assumed to be safe. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Size distributions and sources of elements in particulate matter at curbside, urban and rural sites in Beijing
Jingchun Duan | Jihua Tan | Shulan Wang | Jimin Hao | Fahe Chai
Volume 24, Issue 1, January 2012, Pages 87-94
Size distributions of 29 elements in aerosols collected at urban, rural and curbside sites in Beijing were studied. High levels of Mn, Ni, As, Cd and Pb indicate the pollution of toxic heavy metals cannot be neglected in Beijing. Principal component analysis (PCA) indicates 4 sources of combustion emission, crust related sources, traffic related sources and volatile species from coal combustion. The elements can be roughly divided into 3 groups by size distribution and enrichment factors method (EFs). Group 1 elements are crust related and mainly found within coarse mode including Al, Mg, Ca, Sc, Ti, Fe, Sr, Zr and Ba; Group 2 elements are fossil fuel related and mostly concentrated in accumulation mode including S, As, Se, Ag, Cd, Tl and Pb; Group 3 elements are multi-source related and show multi-mode distribution including Be, Na, K, Cr, Mn, Co, Ni, Cu, Zn, Ga, Mo, Sn and Sb. The EFs of Be, S, Cr, Co, Ni, Cu, Ga, Se, Mo, Ag, Cd, Sb, Tl and Pb show higher values in winter than in summer indicating sources of coal combustion for heating in winter. The abundance of Cu and Sb in coarse mode is about 2-6 times higher at curbside site than at urban site indicating their traffic sources. Coal burning may be the major source of Pb in Beijing since the phase out of leaded gasoline, as the EFs of Pb are comparable at both urban and curbside sites, and about two times higher in winter than that in summer. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Effect of artificial aeration on the performance of vertical-flow constructed wetland treating heavily polluted river water
Huiyu Dong | Zhimin Qiang | Tinggang Li | Hui Jin | Weidong Chen
Volume 24, Issue 4, April 2012, Pages 596-601
Three lab-scale vertical-flow constructed wetlands (VFCWs), including the non-aerated (NA), intermittently aerated (IA) and continuously aerated (CA) ones, were operated at different hydraulic loading rates (HLRs) to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water. Results indicated that artificial aeration increased the dissolved oxygen (DO) concentrations in IA and CA, which significantly favored the removal of organic matter and NH 4+-N. The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen (TN). Although the removal efficiencies of COD Cr, NH 4+-N and TN in the three VFCWs all decreased with an increase in HLR, artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings. The maximal removal efficiencies of COD Cr, NH 4+-N and total phosphorus (TP) (i.e., 81%, 87% and 37%, respectively) were observed in CA at 19 cm/day HLR, while the maximal TN removal (i.e., 57%) was achieved in IA. Although the improvement of artificial aeration on TP removal was limited, this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted river water, particularly at a high HLR. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Levels, sources and health risks of carbonyls and BTEX in the ambient air of Beijing, China
Yujie Zhang | Yujing Mu | Junfeng Liu | Abdelwahid Mellouki
Volume 24, Issue 1, January 2012, Pages 124-130
The atmospheric concentrations of carbonyls and BTEX (benzene, toluene, ethylbenzene, m,p-xylene and o-xylene) were measured simultaneously at a same sampling site in Beijing from September 2008 to August 2010. The average concentrations of the total measured carbonyls during autumn, winter, spring, and summer were 37.7, 31.3, 39.7, 50.5 μg/m 3, respectively, and maximal values for their diurnal variations usually happened at noontime. In contrast to carbonyls, the average concentrations of the total measured BTEX during the four seasons were 27.2, 31.9, 23.2, 19.1 μg/m 3, respectively, and minimal values for their diurnal variations always occurred in the early afternoon. The average concentration for carbonyls increased about 24% from September 2008-August 2009 to September 2009-August 2010, for BTEX, increased about 15%. Integrated life time cancer risks for three carcinogens (benzene, formaldehyde and acetaldehyde) in Beijing exceeded the value of 1E-06, and the hazard quotient (HQ) of non-cancer risk of exposure to formaldehyde exceeded unity. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Adsorption of heavy metal ions from aqueous solution by carboxylated cellulose nanocrystals
Xiaolin Yu | Shengrui Tong | Maofa Ge | Lingyan Wu | Junchao Zuo | Changyan Cao | Weiguo Song
Volume 25, Issue 5, May 2013, Pages 933-943
A novel nanoadsorbent for the removal of heavy metal ions is reported. Cotton was first hydrolyzed to obtain cellulose nanocrystals (CNCs). CNCs were then chemically modified with succinic anhydride to obtain SCNCs. The sodic nanoadsorbent (NaSCNCs) was further prepared by treatment of SCNCs with saturated NaHCO3 aqueous solution. Batch experiments were carried out with SCNCs and NaSCNCs for the removal of Pb2+ and Cd2+. The effects of contact time, pH, initial adsorption concentration, coexisting ions and the regeneration performance were investigated. Kinetic studies showed that the adsorption equilibrium time of Pb2+ and Cd2+ was reached within 150 min on SCNCs and 5 min on NaSCNCs. The adsorption capacities of Pb2+ and Cd2+ on SCNCs and NaSCNCs increased with increasing pH. The adsorption isotherm was well fitted by the Langmuir model. The maximum adsorption capacities of SCNCs and NaSCNCs for Pb2+ and Cd2+ were 367.6 mg/g, 259.7 mg/g and 465.1 mg/g, 344.8 mg/g, respectively. SCNCs and NaSCNCs showed high selectivity and interference resistance from coexisting ions for the adsorption of Pb2+. NaSCNCs could be efficiently regenerated with a mild saturated NaCl solution with no loss of capacity after two recycles. The adsorption mechanisms of SCNCs and NaSCNCs were discussed. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Acid Blue 25 adsorption on base treated Shorea dasyphylla sawdust: Kinetic, isotherm, thermodynamic and spectroscopic analysis
Megat Ahmad Kamal Megat Hanafiah | Wan Saime Wan Ngah | Shahira Hilwani Zolkafly | Lee Ching Teong | Zafri Azran Abdul Majid
Volume 24, Issue 2, February 2012, Pages 261-268
The potential of base treated Shorea dasyphylla (BTSD) sawdust for Acid Blue 25 (AB 25) adsorption was investigated in a batch adsorption process. Various physiochemical parameters such as pH, stirring rate, dosage, concentration, contact time and temperature were studied. The adsorbent was characterized with Fourier transform infrared spectrophotometer, scanning electron microscope and Brunauer, Emmett and Teller analysis. The optimum conditions for AB 25 adsorption were pH 2, stirring rate 500 r/min, adsorbent dosage 0.10 g and contact time 60 min. The pseudo second-order model showed the best conformity to the kinetic data. The equilibrium adsorption of AB 25 was described by Freundlich and Langmuir, with the latter found to agree well with the isotherm model. The maximum monolayer adsorption capacity of BTSD was 24.39 mg/g at 300 K, estimated from the Langmuir model. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy were determined. It was found that AB 25 adsorption was spontaneous and exothermic. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

A comparative study of Mn/CeO2, Mn/ZrO2 and Mn/Ce-ZrO2 for low temperature selective catalytic reduction of NO with NH3 in the presence of SO2 and H2O
Boxiong Shen | Xiaopeng Zhang | Hongqing Ma | Yan Yao | Ting Liu
Volume 25, Issue 4, April 2013, Pages 791-800
Ce-ZrO2 is a widely used three-way catalyst support. Because of the large surface area and excellent redox quality, Ce-ZrO2 may have potential application in selective catalytic reduction (SCR) systems. In the present work, Ce-ZrO2 was introduced into a low-temperature SCR system and CeO2 and ZrO2 supports were also introduced to make a contrastive study. Mn/CeO2, Mn/ZrO2 and Mn/Ce-ZrO2 were prepared by impregnating these supports with Mn(NO3)2 solution, and have been characterized by N2-BET, XRD, TPR, TPD, XPS, FT-IR and TG. The activity and resistance to SO2 and H2O of the catalysts were investigated. Mn/Ce-ZrO2 and Mn/CeO2 were proved to have better low-temperature activities than Mn/ZrO2, and yielded 98.6% and 96.8% NO conversion at 180°C, respectively. This is mainly because Mn/Ce-ZrO2 and Mn/CeO2 had higher dispersion of manganese oxides, better redox properties and more weakly adsorbed oxygen species than Mn/ZrO2. In addition, Mn/Ce-ZrO2 showed a good resistance to SO2 and H2O and presented 87.1% NO conversion, even under SO2 and H2O treatment for 6 hours, and the activity of Mn/Ce-ZrO2 was almost restored to its original level after cutting off the injection of SO2 and H2O. This was due to the weak water absorption and weak sulfation process on the surface of the catalyst. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Degradation kinetics and mechanism of aniline by heat-assisted persulfate oxidation
Xiaofang Xie | Yongqing Zhang | Weilin Huang | Shaobing Huang
Volume 24, Issue 5, May 2012, Pages 821-826
Oxidation of aniline by persulfate in aqueous solutions was investigated and the reaction kinetic rates under different temperature, persulfate concentration and pH conditions were examined in batch experiments. The results showed that, the aniline degradation followed pseudo first-order reaction model. Aniline degradation rate increased with increasing temperature or persulfate concentration. In the pH range of 3 to 11, a low aniline degradation rate was obtained at strong acid system (pH 3), while a high degradation rate was achieved at strong alkalinity (pH 11). Maximum aniline degradation occurred at pH 7 when the solution was in a weak level of acid and alkalinity (pH 5, 7 and 9). Produced intermediates during the oxidation process were identified using liquid chromatography-mass spectrometry technology. And nitrobenzene, 4-4'-diaminodiphenyl and 1-hydroxy-1,2-diphenylhydrazine have been identified as the major intermediates of aniline oxidation by persulfate and the degradation mechanism of aniline was also tentatively proposed. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Assessment of source water contamination by estrogenic disrupting compounds in China
Weiwei Jiang | Ye Yan | Mei Ma | Donghong Wang | Qian Luo | Zijian Wang | Senthil Kumaran Satyanarayanan
Volume 24, Issue 2, February 2012, Pages 320-328
Detection of estrogenic disrupting compounds (EDCs) in drinking waters around China has led to rising concerns about health risks associated with these compounds. There is, however, a paucity of studies on the occurrence and identification of the main compounds responsible for this pollution in the source waters. To fill this void, we screened estrogenic activities of 23 source water samples from six main river systems in China, using a recombinant two-hybrid yeast assay. All sample extracts induced significant estrogenic activity, with E2 equivalents (EEQ) of raw water ranging from 0.08 to 2.40 ng/L. Additionally, 16 samples were selected for chemical analysis by gas chromatography-mass spectrometry. The EDCs of most concern, including estrone (E1), 17β-estradiol (E2), 17a-ethinylestradiol (EE2), estriol (E3), diethylstilbestrol (DES), estradiol valerate (EV), 4-t-octylphenol (4-t-OP), 4-nonylphenols (4-NP) and bisphenol A (BPA), were determined at concentrations of up to 2.98, 1.07, 2.67, 4.37, 2.52, 1.96, 89.52, 280.19 and 710.65 ng/L, respectively. Causality analysis, involving comparison of EEQ values from yeast assay and chemical analysis identified E2, EE2 and 4-NP as the main responsible compounds, accounting for the whole estrogenic activities (39.74% to 96.68%). The proposed approach using both chemical analysis and yeast assay could be used for the identification and evaluation of EDCs in source waters of China. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

A review of polybrominated diphenyl ethers and alternative brominated flame retardants in wildlife from China: Levels, trends, and bioaccumulation characteristics
Jiangping Wu | Ying Zhang | Xiaojun Luo | Yazhe She | Lehuan Yu | Shejun Chen | Bixian Mai
Volume 24, Issue 2, February 2012, Pages 183-194
Accelerated industrialization and urbanization, and unregulated disposal of waste of electric and electronic equipment (e-waste) in China have caused environmental pollution of brominated flame retardants (BFRs). This review summarized the levels, trends, and bioaccumulation characteristics of polybrominated diphenyl ethers (PBDEs) and other potential alternative BFRs including hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-dibromophenoxy) ethane (BTBPE) and decabromodiphenylethane (DBDPE) in wildlife from China. PBDE levels in wildlife from China were generally higher than those from other parts in Asia, and were comparable to those from Europe but were lower than those from North America. However, wildlife from the e-waste recycling sites in South China and East China contained much higher PBDEs compared to other reports around the world, suggesting the heavy contamination of PBDEs in these regions. The alternative BFRs were also detected in wildlife, revealing that the animals are exposed to these chemicals, in addition to PBDEs. Temporal trends indicated by levels in marine mammals from South China suggested that PBDE levels increased from the beginning of 1990s to 2000s, but decreased from the middle of 2000s, followed by relatively steady levels. In contrast, HBCDs were found to be continuously increasing from 1997 to 2007, indicating the increasing usage of HBCDs in China in recent years. Compared to PBDE profiles found in other parts, aquatic species and birds from China contained relatively higher contributions of BDE-28 and 209, respectively, suggesting the possible different usage pattern of PBDEs. Future works including keeping monitoring at a reasonable scale and frequency to make sure levels near urban centers indicative of population do not increase are needed. Additionally, focus effort on e-waste recycling regions to look for impacts and to determine if regulation/controls are resulting in lower environmental contamination, and incorporation of sentinel species in monitoring efforts are recommended. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Aerosol scattering coefficients and major chemical compositions of fine particles observed at a rural site in the central Pearl River Delta, South China
Xinming Wang | Xiang Ding | Xiaoxin Fu | Quanfu He | Shaoyi Wang | Franc?is Bernard | Xiuying Zhao | Dui Wu
Volume 24, Issue 1, January 2012, Pages 72-77
During November-December 2010 aerosol scattering coefficients were monitored using a single-waved (525 nm) Nephelometer at a regional monitoring station in the central Pearl River Delta region and 24-hr fine particle (PM 2.5) samples were also collected during the period using quartz filters for the analysis of major chemical components including organic carbon (OC), elemental carbon (EC), sulfate, nitrate and ammonium. In average, these five components accounted for about 85% of PM 2.5 mass and contributed 42% (OC), 19% (SO 42-), 12% (NO 3-), 8.4% (NH 4+) and 3.7% (EC), to PM 2.5 mass. A relatively higher mass scattering efficiency of 5.3 m 2/g was obtained for fine particles based on the linear regression between scattering coefficients and PM2.5 mass concentrations. Chemical extinction budget based on IMPROVE approach revealed that ammonium sulfate, particulate organic matter, ammonium nitrate and EC in average contributed about 32%, 28%, 20% and 6% to the light extinction coefficients, respectively. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Carbon dioxide capture using polyethylenimine-loaded mesoporous carbons
Jitong Wang | Huichao Chen | Huanhuan Zhou | Xiaojun Liu | Wenming Qiao | Donghui Long | Licheng Ling
Volume 25, Issue 1, January 2013, Pages 124-132
A high efficiency sorbent for CO2 capture was developed by loading polyethylenimine (PEI) on mesoporous carbons which possessed well-developed mesoporous structures and large pore volume. The physicochemical properties of the sorbent were characterized by N2 adsorption/desorption, scanning electron microscopy (SEM), thermal gravimetric analysis (TG) and Fourier transform infrared spectroscopy (FT-IR) techniques followed by testing for CO2 capture. Factors that affected the sorption capacity of the sorbent were studied. The sorbent exhibited extraordinary capture capacity with CO2 concentration ranging from 5% to 80%. The optimal PEI loading was determined to be 65 wt.% with a CO2 sorption capacity of 4.82 mmol-CO2/g-sorbent in 15% CO2/N2 at 75°C, owing to low mass-transfer resistance and a high utilization ratio of the amine compound (63%). Moisture had a promoting effect on the sorption separation of CO2. In addition, the developed sorbent could be regenerated easily at 100°C, and it exhibited excellent regenerability and stability. These results indicate that this PEI-loaded mesoporous carbon sorbent should have a good potential for CO2 capture in the future. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Comparison of the toxicity of silver nanoparticles and silver ions on the growth of terrestrial plant model Arabidopsis thaliana
Haifeng Qian | Xiaofeng Peng | Xiao Han | Jie Ren | Liwei Sun | Zhengwei Fu
Volume 25, Issue 9, September 2013, Pages 1947-1955
Silver nanoparticles (AgNPs) are one of the most widely used nanomaterials, but the mechanism of AgNP toxicity in terrestrial plants is still unclear. We compared the toxic effects of AgNPs and Ag+ on Arabidopsis thaliana at the physiological, ultrastructural and molecular levels. AgNPs did not affect seed germination; however, they showed stronger inhibitory effect on root elongation than Ag+. The results of transmission electron microscopy and metal content analysis showed that AgNPs could be accumulated in leaves. These absorbed AgNPs disrupted the thylakoid membrane structure and decreased chlorophyll content, which can inhibit plant growth. By comparison, a small amount of Ag+ was absorbed by seedlings, and it did not pronouncedly affect chloroplast structure and other metal ion absorption as AgNPs did. Compared with Ag+, AgNPs could alter the transcription of antioxidant and aquaporin genes, indicating that AgNPs changed the balance between the oxidant and antioxidant systems, and also affected the homeostasis of water and other small molecules within the plant body. All the data from physiological, ultrastructural and molecular levels suggest that AgNPs were more toxic than Ag+. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Real-world fuel efficiency and exhaust emissions of light-duty diesel vehicles and their correlation with road conditions
Jingnan Hu | Ye Wu | Zhishi Wang | Zhenhua Li | Yu Zhou | Haitao Wang | Xiaofeng Bao | Jiming Hao
Volume 24, Issue 5, May 2012, Pages 865-874
The real-world fuel efficiency and exhaust emission profiles of CO, HC and NOx for light-duty diesel vehicles were investigated. Using a portable emissions measurement system, 16 diesel taxies were tested on different roads in Macao and the data were normalized with the vehicle specific power bin method. The 11 Toyota Corolla diesel taxies have very good fuel economy of (5.9 ± 0.6) L/100 km, while other five diesel taxies showed relatively high values at (8.5 ± 1.7) L/100 km due to the variation in transmission systems and emission control strategies. Compared to similar Corolla gasoline models, the diesel cars confirmed an advantage of ca. 20% higher fuel efficiency. HC and CO emissions of all the 16 taxies are quite low, with the average at (0.05 ± 0.02) g/km and (0.38 ± 0.15) g/km, respectively. The average NOx emission factor of the 11 Corolla taxies is (0.56 ± 0.17) g/km, about three times higher than their gasoline counterparts. Two of the three Hyundai Sonata taxies, configured with exhaust gas recirculation (EGR) + diesel oxidation catalyst (DOC) emission control strategies, indicated significantly higher NO2 emissions and NO2/NOx ratios than other diesel taxies and consequently trigger a concern of possibly adverse impacts on ozone pollution in urban areas with this technology combination. A clear and similar pattern for fuel consumption and for each of the three gaseous pollutant emissions with various road conditions was identified. To save energy and mitigate CO2 emissions as well as other gaseous pollutant emissions in urban area, traffic planning also needs improvement. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Effectiveness of national air pollution control policies on the air quality in metropolitan areas of China
Shuxiao Wang | Jia Xing | Bin Zhao | Carey Jang | Jiming Hao
Volume 26, Issue 1, January 2014, Pages 13-22
Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide (SO2) control policy during the 11th Five Year Plan period (2006-2010) had succeeded in reducing the national SO2 emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2 and sulfate (SO42-) concentrations by 13%-15% and 8%-10% respectively over east China. The nitrogen oxides (NOx) control policy during the 12th Five Year Plan period (2011-2015) targets the reduction of the national NOx emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NOx emission will reduce the ambient nitrogen dioxide (NO2), nitrate (NO3-), 1-hr maxima ozone (O3) concentrations and total nitrogen deposition by 8%, 3%-14%, 2% and 2%-4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3- 1-hr maxima O3 concentrations and total nitrogen deposition by 2%-4%, 1%-6%, 0-2% and 1%-2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control. ? 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Using lysosomal membrane stability of haemocytes in Ruditapes philippinarum as a biomarker of cellular stress to assess contamination by caffeine, ibuprofen, carbamazepine and novobiocin
Gabriela V. Aguirre-Martínez | Sara Buratti | Elena Fabbri | Angel T. DelValls | M. Laura Martín-Díaz
Volume 25, Issue 7, July 2013, Pages 1408-1418
Although pharmaceuticals have been detected in the environment only in the range from ng/L to μg/L, it has been demonstrated that they can adversely affect the health status of aquatic organisms. Lysosomal membrane stability (LMS) has previously been applied as an indicator of cellular well-being to determine health status in bivalve mussels. The objective of this study is to evaluate LMS in Ruditapes philippinarum haemolymph using the neutral red retention assay (NRRA). Clams were exposed in laboratory conditions to caffeine (0.1, 5, 15, 50 μg/L), ibuprofen (0.1, 5, 10, 50 μg/L), carbamazepine and novobiocin (both at 0.1, 1, 10, 50 μg/L) for 35 days. Results show a dose-dependent effect of the pharmaceuticals. The neutral red retention time measured at the end of the bioassay was significantly reduced by 50% after exposure to environmental concentrations (. p < 0.05) (caffeine = 15 μg/L; ibuprofen = 10 μg/L; carbamazepine = 1 μg/L and novobiocin = 1 μg/L), compared to controls. Clams exposed to these pharmaceuticals were considered to present a diminished health status (retention time < 45 min), significantly worse than controls (96 min) (. p < 0.05). The predicted no environmental effect concentration (PNEC) results showed that these pharmaceuticals are very toxic at the environmental concentrations tested. Measurement of the alteration of LMS has been found to be a sensitive technique that enables evaluation of the health status of clams after exposure to pharmaceuticals under laboratory conditions, thus representing a robust Tier-1 screening biomarker. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Fate of tetracyclines in swine manure of three selected swine farms in China
Min Qiao | Wangda Chen | Jianqiang Su | Bing Zhang | Cai Zhang
Volume 24, Issue 6, June 2012, Pages 1047-1052
Veterinary antibiotics can enter the environment due to the common practice of land application of manure from treated animals. The environmental fate of tetracyclines in swine manure after composting and field application remains largely unknown. This study analyzed the concentrations of tetracyclines in manure, manure-based compost and compost amended soil in selected swine farms from Beijing, Jiaxing and Putian, China to determine the dilution effects of antibiotics when released into the soil environment. The results demonstrate that residues of antibiotics were detected in all samples and chlortetracycline as well as its degradation products should be regarded critically concerning their potential ecotoxicity. Application of manure-based compost to soil could reduce the possible risk posed by antibiotic contamination, but the trigger value of 100 μg/kg was still exceeded in soil samples (776.1 μg/kg dw) from Putian City after application of compost. Field studies such as the present one can help to improve the routine administration of antibiotic-containing composted manure. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Determination of the mechanism of photoinduced toxicity of selected metal oxide nanoparticles (ZnO, CuO, Co3O4 and TiO2) to E. coli bacteria
Thabitha P. Dasari | Kavitha Pathakoti | Huey Min Hwang
Volume 25, Issue 5, May 2013, Pages 882-888
Cytotoxicity of selected metal oxide nanoparticles (MNPs) (ZnO, CuO, Co3O4 and TiO2) was investigated in Escherichia coli both under light and dark conditions. Cytotoxicity experiments were conducted with spread plate counting and the LC50 values were calculated. We determined the mechanism of toxicity via measurements of oxidative stress, reduced glutathione, lipid peroxidation, and metal ions. The overall ranking of the LC50 values was in the order of ZnO < CuO < Co3O4 < TiO2 under dark condition and ZnO < CuO < TiO2 < Co3O4 under light condition. ZnO MNPs were the most toxic among the tested nanoparticles. Our results indicate depletion of reduced glutathione level and elevation of malondialdehyde level correlated with the increase in oxidative stress. Released metal ions were found to have partial effect on the toxicity of MNPs to E. coli. In summary, the dynamic interactions of multiple mechanisms lead to the toxicity of the tested MNPs to E. coli. ? 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Photocatalytic degradation of 4-chlorophenol under P-modified TiO 2/UV system: Kinetics, intermediates, phytotoxicity and acute toxicity
Kais Elghniji | Olfa Hentati | Najwa Mlaik | Ayman Mahfoudh | Mohamed Ksibi
Volume 24, Issue 3, March 2012, Pages 479-487
A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO 2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900°C. Kinetic studies on the P-modified TiO 2 to degraded 4-chlorophenol had found that the TP5 500 prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500°C had an apparent rate constant equal to 0.0075 min -1, which is superior to the performance of a commercial photocatalyst Degussa P25 K app = 0.0045 min -1 and of unmodified TiO 2 (TP0 500) K app = 0.0022 min -1. From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone (HQ), benzoquinone (BQ) and (4CC) 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato (Lycopersicon esculentum) whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Removal of tetracycline from water by Fe-Mn binary oxide
Huijuan Liu | Yang Yang | Jin Kang | Maohong Fan | Jiuhui Qu
Volume 24, Issue 2, February 2012, Pages 242-247
Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments. A series of Fe-Mn binary oxide with different Fe:Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal. Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide, and that the oxide with a Fe:Mn molar ratio of 5:1 was the best in removal than other molar ratios. The tetracycline removal was highly pH dependent. The removal of tetracycline decreased with the increase of initial concentration, but the absolute removal quantity was more at high concentration. The presence of cations and anions such as Ca 2+, Mg 2+, CO 32- and SO 42- had no significant effect on the tetracycline removal in our experimental conditions, while SiO 32- and PO 43- had hindered the adsorption of tetracycline. The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface. This primary study suggests that Fe-Mn binary oxide with a proper Fe:Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions. ? 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

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