Guorui Liu

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (35)94.02 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Thermal experiments (at 250-450°C for 10-240min) on fly ash from secondary copper smelting process (SeCu) were performed to study the polychlorinated naphthalene (PCN) formation in the post-zone of a secondary copper smelter. Unexpectedly high concentrations of PCNs were formed. Total PCN concentrations and toxic equivalents were 47-104 and 44-80 times higher than the initial concentration and toxic equivalent, respectively. The thermal disposal of SeCu fly ash should therefore be reconsidered. The kinetic of each homolog was determined under different thermal conditions. Less chlorinated homologs favored 350°C and more chlorinated homologs favored higher temperature. Most of the homologs reached an equilibrium of formation and degradation within 30min, except octachloronaphthalene which did not appear to reach such an equilibrium even after 240min. Chlorine substitution of the formed PCNs was identified and a similar pattern was found in chlorination products starting with naphthalene and chlorine. Furthermore, inorganic chlorine and unsubstituted naphthalene were found in the reaction products, confirming that the formation of naphthalene and the chlorination of that naphthalene could occur and could be suggested to be an important PCN formation route. A detailed formation pathway from naphthalene through octachloronaphthalene is proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Chemosphere 10/2014; 119C:1091-1098. · 3.14 Impact Factor
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    ABSTRACT: Iron foundries have been identified as dioxin sources in previous field investigations. Similar formation mechanisms between dioxins and unintentional polychlorinated naphthalenes (PCNs) have led us to speculate that iron foundries are also potential PCN sources. In this study, PCNs in stack gas and fly ash samples representing atmospheric and residue emissions from 13 typical iron foundry plants were analyzed. The average emission factor of ∑2-8PCNs to residue was calculated to be 61 µg t-1, with a range of 10-107 µg t-1. The emission factors of ∑2-8PCNs to air in two case plants were 267 and 1472 µg t-1. The derived emission factors might be useful for estimating annual emissions and understanding the contribution of PCNs from iron foundries. The possible formation mechanisms of PCNs, based on the PCN profiles, are discussed. Successive reductions in the abundance of homologs were observed to occur with the increase in chlorine substituted numbers. Abundances of congeners containing more β-position chlorines in the naphthalene skeleton were much higher than those of congeners containing more α-position chlorines for penta-, hexa- and hepta- homologs, which suggests that the β-positions are favored for chlorination. Potential chlorination pathways from tetra- to octa- homologs are proposed.
    Environmental science & technology. 10/2014;
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    ABSTRACT: Identifying marker congeners of unintentionally produced polychlorinated naphthalenes (PCNs) from industrial thermal sources might be useful for predicting total PCN (∑2-8PCN) emissions by the determination of only indicator congeners. In this study, potential indicator congeners were identified based on the PCN data in 122 stack gas samples from over 60 plants involved in more than ten industrial thermal sources reported in our previous case studies. Linear regression analyses identified that the concentrations of CN27/30, CN52/60, and CN66/67 correlated significantly with ∑2-8PCN (R(2)=0.77, 0.80, and 0.58, respectively; n=122, p<0.05), which might be good candidates for indicator congeners. Equations describing relationships between indicators and ∑2-8PCN were established. The linear regression analyses involving 122 samples showed that the relationships between the indicator congeners and ∑2-8PCN were not significantly affected by factors such as industry types, raw materials used, or operating conditions. Hierarchical cluster analysis and similarity calculations for the 122 stack gas samples were adopted to group those samples and evaluating their similarity and difference based on the PCN homolog distributions from different industrial thermal sources. Generally, the fractions of less chlorinated homologs comprised of di-, tri-, and tetra-homologs were much higher than that of more chlorinated homologs for up to 111 stack gas samples contained in group 1 and 2, which indicating the dominance of lower chlorinated homologs in stack gas from industrial thermal sources.
    Chemosphere 09/2014; 118C:194-200. · 3.14 Impact Factor
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    ABSTRACT: Hot dip galvanizing (HDG) processes are sources of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs). Close correlations have been found between the concentration of PCDD/Fs and polychlorinated naphthalenes (PCNs) that are produced and released during industrial thermal processes. We speculated, therefore, that HDG plants are potential PCN sources. In this preliminary study, PCNs were analyzed in solid residues, ash and precipitate from three HDG plants of different sizes. The total PCN concentrations (∑2-8PCNs) in the residue samples ranged from 60.3 to 226pgg(-1). The PCN emission factors for the combined ash and precipitate residues from the HDG plants ranged from 75 to 178ngt(-1) for the dichlorinated and octachlorinated naphthalenes. The preliminary results suggested that the HDG industry might not currently be a significant source of PCN emissions. The trichloronaphthalenes were the dominant homologs followed by the dichloronaphthalenes and the tetrachloronaphthalenes. The PCN congeners CN37/33/34, CN52/60, CN66/67, and CN73 dominated the tetrachlorinated, pentachlorinated, hexachlorinated, and heptachlorinated naphthalene homologs, respectively. The PCNs emitted from the HDG plants had similar homolog distributions and congener profiles to the PCNs emitted from combustion plants and other metallurgical processes. The identification and preliminary evaluation of PCN emissions from HDG plants presented here will help in the prioritization of measures for controlling PCN emissions from industrial sources.
    Chemosphere 07/2014; 118C:112-116. · 3.14 Impact Factor
  • Guorui Liu, Minghui Zheng, Zongwei Cai
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    ABSTRACT: Polychlorinated naphthalenes (PCNs) have been proposed for inclusion in the annexes of the Stockholm Convention by the European Union, signifying a probable increase in monitoring PCN levels at a global level. Investigations on PCN levels in the environment of Hong Kong have not been reported. In this preliminary investigation, PCN levels in surface soils samples were determined by isotope dilution HRGC/HRMS techniques, and compared with those of polychlorinated biphenyl (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The concentrations of PCNs in the soil samples were 35-883 pg g(-1) (average, 201; and median, 94 pg g(-1)), which were lower than those of PCBs PCDDs and PCDFs. This comparison suggested that PCNs are currently not priority POPs compared with dioxins and PCBs in Hong Kong soils. PCDDs were the most important contributor to the sum of toxic equivalents of PCNs, PCBs, PCDDs and PCDFs. OCDD was the most dominant dioxin congener in Hong Kong surface soils. PCB-118 was the most abundant in 12 dl-PCB congeners. PCN congeners indicating thermal related sources (CN52/60, CN66/67 and CN73) were relatively abundant in their respective homologs, which suggested PCN contamination from thermal sources. The ratio of CN73 to CN74 in soil samples suggested the contribution of PCN contaminations in soils from both thermal-related sources and evaporative emissions of technical PCN mixtures.
    Environmental Science and Pollution Research 07/2014; · 2.76 Impact Factor
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    ABSTRACT: Unintentionally produced persistent organic pollutants (UP-POPs) were determined in ambient air from around five secondary non-ferrous metal processing plants in China, to investigate the potential impacts of the emissions of these plants on their surrounding environments. The target compounds were polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs). The PCDD/F, dl-PCB, and PCN concentrations in the ambient air downwind of the plants were 4.70-178, 8.23-7520 and 152-4190 pg/m(3), respectively, and the concentrations upwind of the plants were lower. Clear correlations were found between ambient air and stack gas concentrations of the PCDD/Fs, dl-PCBs, and PCNs among the five plants, respectively. Furthermore, the UP-POPs homolog and congener patterns in the ambient air were similar to the patterns in the stack gas samples. These results indicate that UP-POPs emissions from the plants investigated have obvious impacts on the environments surrounding the plants.
    Environmental pollution (Barking, Essex : 1987). 06/2014; 193C:6-12.
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    ABSTRACT: Polychlorinated naphthalenes (PCNs) were nominated as persistent organic pollutants candidate in the Stockholm Convention in 2011. In this study, the profiles, concentrations and spatial distributions of PCNs were analyzed in 30 sewage sludge samples from wastewater treatment plants (WWTPs) in China. Concentrations of Σ75PCNs in sludge samples were in the range of 1.05-10.9ng/g dry weight (dw) with a mean value of 3.98ng/gdw. The predominant homologues in the sludge were mono- to tetra-CNs, accounting for approximately 85% of total PCNs. The total toxic equivalent quantities (TEQs) of dioxin-like PCN congeners ranged from 0.04 to 2.28pg/gdw with a mean value of 0.36pg/gdw, which were lower than the maximum permissible TEQ concentrations in sludge for land application in China. Levels of PCNs and TEQs in sludge were relatively higher in samples from highly industrialized and developed cities in eastern China, implying a possible link between PCN contamination and the local economic development, but more studies are warranted to corroborate this. Industrial sources might be important contributors of PCNs to sewage sludge in China.
    Science of The Total Environment 05/2014; 490C:555-560. · 3.16 Impact Factor
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    ABSTRACT: Unintentionally produced persistent organic pollutants (UP-POPs) including polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were characterized and quantified in stack gas and fly ash from the second ventilation systems in five typical converters in five different steelmaking plants. The 2378-substituted PCDD/Fs (2378-PCDD/Fs) and dioxin-like PCB (dl-PCBs) toxic equivalents (TEQs) were 1.84-10.3 pg WHO-TEQ Nm(-3) in the stack gas and 5.59-87.6 pg WHO-TEQ g(-1) in the fly ash, and the PCN TEQs were 0.06-0.56 pg TEQ Nm(-3) in the stack gas and 0.03-0.08 pg TEQ g(-1) in the fly ash. The concentrations of UP-POPs in the present study were generally lower than those in other metallurgical processes, such as electric arc furnaces, iron ore sintering, and secondary metallurgical processes. Adding scrap metal might increase UP-POP emissions, indicating that raw material composition was a key influence on emissions. HxCDF, HpCDF, OCDF, HpCDD, and OCDD were the dominant PCDD/Fs in the stack gas and fly ash. TeCB and PeCB were dominant in the stack gas, but HxCB provided more to the total PCB concentrations in the fly ash. The lower chlorinated PCNs were dominant in all of the samples. The 2378-PCDD/F, dl-PCB, and PCN emission factors in stack gases from the steelmaking converter processes (per ton of steel produced) were 1.88-2.89, 0.14-0.76, and 229-759 μg t(-1), respectively.
    Environmental Science and Pollution Research 03/2014; · 2.76 Impact Factor
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    ABSTRACT: Unintentionally produced persistent organic pollutants (UP-POPs) were determined in ambient air from around five secondary non-ferrous metal processing plants in China, to investigate the potential impacts of the emissions of these plants on their surrounding environments. The target compounds were polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs). The PCDD/F, dl-PCB, and PCN concentrations in the ambient air downwind of the plants were 4.70–178, 8.23–7520 and 152–4190 pg/m3, respectively, and the concentrations upwind of the plants were lower. Clear correlations were found between ambient air and stack gas concentrations of the PCDD/Fs, dl-PCBs, and PCNs among the five plants, respectively. Furthermore, the UP-POPs homolog and congener patterns in the ambient air were similar to the patterns in the stack gas samples. These results indicate that UP-POPs emissions from the plants investigated have obvious impacts on the environments surrounding the plants.
    Environmental Pollution. 01/2014; 193:6–12.
  • Chinese Journal 01/2014; 59(16):1479.
  • Guorui Liu, Zongwei Cai, Minghui Zheng
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    ABSTRACT: The European Union has proposed that polychlorinated naphthalenes (PCNs) should be included in the annexes of the Stockholm Convention on Persistent Organic Pollutants, signifying that there will be an increase in activities aimed at reducing PCN emissions. It has been speculated that the unintentional formation and emission of PCNs from industrial activities are the main current sources, because they have ceased to be manufactured as industrial chemicals in many countries. In this review, we provide a brief overview of recent progress in research into the unintentional formation and emission of PCNs from various industries that use thermal processes. The sampling and analysis of PCNs, and their formation mechanisms during thermal processes, are reviewed and discussed. The emission levels, emission profiles, and emission factors of PCNs from a number of industries that use thermal processes are summarized and compared, and this will provide helpful information for planning PCN source control measures and studying the source-receptor relationships of PCNs.
    Chemosphere 10/2013; · 3.14 Impact Factor
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    ABSTRACT: An isotope dilution gas chromatography combined with triple quadrupole mass spectrometry (GC-MS/MS) method was established for the analysis of twenty polychlorinated naphthalenes (PCNs) congeners in environmental samples. The linear correlation coefficients (R2) of calibration curves were greater than 0.99 in the concentration range of 0.5 - 200 microg/L for all the twenty PCN congeners. The average relative response factors (RRF) were calculated based on a seven-point calibration for the twenty PCN congeners. The relative standard deviations (RSDs) of all the congeners were below 15% (n = 7). The limits of detection (LOD) of the established method ranged from 0.04 to 0.48 microg/L for the twenty PCN congeners. The recoveries of matrix spiked samples ranged from 45.2% to 87.9%, and the RSDs ranged from 0.4% to 21.2%. The sediment samples and stack gas samples collected from secondary aluminum smelting were analyzed by the established method. The obtained results were also compared with the data analyzed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) method. The comparison indicated that the data of the established method was in good agreement with those of HRGC/HRMS method with the RSDs of 0.5% - 41.4%. Consequently, the established GC-MS/MS method can be applied to the determination of PCNs in environmental samples.
    Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 09/2013; 31(9):878-84.
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    ABSTRACT: The coking process has been found to be an important source of unintentionally produced persistent organic pollutants (UP-POPs). However, the concentrations, profiles, and emission factors of UP-POPs in fly ash from coke plants have not been studied. In this study, six UP-POPs (polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), hexachlorobenzene (HxCBz), and pentachlorobenzene (PeCBz)) were identified and quantified in fly ash from eight coke plants. The average concentrations of the PCDDs, PCDFs, and "dioxin-like" PCBs were 1.5, 2.26, and 0.26pgTEQg(-1), respectively, and the average concentrations of the PCNs, HxCBz, and PeCBz were 256, 290, and 146pgg(-1), respectively. The proportion each homolog contributed to the total concentration of the PCDFs, PCBs, and PCNs decreased with increasing chlorination level. The PCDFs contributed the biggest proportion of the total UP-POPs toxic equivalents (TEQs), and the average emission factors in fly ash were 10.5, 17.3, and 1.82ngTEQt(-1) for the PCDDs, PCDFs, and "dioxin-like" PCBs, respectively, and 1792, 2028, and 1025ngt(-1) for the PCNs, HxCBz, and PeCBz, respectively. These data are essential for establishing an integrated UP-POP release inventory.
    Journal of hazardous materials 08/2013; 261C:421-426. · 4.33 Impact Factor
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    Guorui Liu, Minghui Zheng
    Environmental Science & Technology 07/2013; · 5.48 Impact Factor
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    ABSTRACT: Sucralose, an artificial sweetener, is being used in increasingly large amounts in foodstuffs and beverages worldwide. Information pertaining to its ability to participate in chlorination reactions during cooking and generate toxic compounds, however, is scarce. In this study, the formation and distribution of polychlorinated naphthalenes (PCNs), which are a group of highly toxic polychlorinated aromatic compounds, in oil heated in the presence of sucralose was investigated. The concentrations of the PCNs present in the cooking oils and oil fumes generated during the heating process were determined by isotope dilution according to a HRGC/HRMS method. The results suggested that the heating of cooking oil in the presence of sucralose promoted the formation of toxic PCNs. Although PCNs were detected in the oil fumes, no PCNs were found in the heated oils. The total concentrations of the PCNs found in peanut and olive oil fumes were 490 and 240 pg g−1, respectively. The degree of chlorination for the PCNs was calculated to be 5.3 for both the peanut and olive oil fumes. To quantify the newly produced PCNs, sucralose used in the experiments were about 2 or 3 orders of magnitude higher than in reality. PCNs were not detected with real proportions under the current experimental conditions.
    Food Control. 07/2013; 32(1):1–5.
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    ABSTRACT: The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs) were determined in workplace air from eight secondary non-ferrous metals processing plants to investigate occupational exposure to these toxic compounds. The total estimated daily intakes of PCDD/Fs and dl-PCBs for workers by inhalation in the workplace were in the range of 0.15-9.91 and 0.13-8.59 pg WHO-TEQ/kg body weight (bw) for moderate and light activities, respectively. The daily inhalation doses for workers in the workplaces of three investigated plants exceeded the tolerable daily intake recommended by WHO. These results indicate that the risk of occupational exposure to dioxins by inhalation in the workplace of plants investigated was considerably high. For PCNs, the daily inhalation doses for workers in the workplace were in the range of 0.005-4.46 and 0.004-3.87 pg TEQ/kg bw for moderate and light activities, respectively, which were lower than that of dioxins. To identify the source of PCDD/F, PCB, and PCN in workplace air, their homolog profiles were compared with those in stack gas from the plants investigated. It was found that significant dioxin contamination in workplace air was mainly attributed to fugitive gas emission from smelting furnaces during reclamation processes.
    Environmental Science & Technology 06/2013; · 5.48 Impact Factor
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    ABSTRACT: Sucralose is a widely-used artificial high-intensity sweetener. Although doubts have been raised about the safety of sucralose by several researchers, it can still be found in a broad range of foods and beverages worldwide, including in baked goods. Sucralose may decompose at high temperatures, and participate in chlorination reactions, generating highly toxic compounds. Here, we demonstrate that heating sucralose at high temperatures in stainless steel or other metal utensils in the presence of rust (Al2O3, Fe2O3, and CuO) produces polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). PCDD/Fs were found in smoke generated during the heating of sucralose and in the residues after heating. CuO enhanced the PCDD/F yield in comparison with Al2O3 and Fe2O3.
    Scientific Reports 01/2013; 3:2946. · 5.08 Impact Factor
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    ABSTRACT: In this study, field measurements were conducted to estimate and characterize the atmospheric emission levels and profiles of polychlorinated biphenyls (PCBs) from multiple industrial thermal processes. The emission levels and profiles of PCBs from five types of thermal processes at twenty-three plants were studied and compared with eight processes reported in our previous studies. Correlation analysis was preformed to identify a marker congener for emission of ΣPCB. A significant correlation was observed between congener CB-118 and ΣPCB (R(2)=0.65 and p<0.01), which suggests that CB-118 is a good marker congener for emission of ΣPCB. The profiles of PCBs emitted from the thirteen thermal processes were compared, and this information could be used for studying source-receptor relationships and identifying the specific sources of PCBs. To prioritize the sources for control, the concentrations of PCBs from thirteen industrial thermal sources were compared. The PCB concentrations from secondary zinc smelting and thermal wire reclamation were about one to three order magnitude higher than those of other sources, which suggests that these two sources be given priority in PCB source control. Finally, the atmospheric emission factors of PCBs from the thirteen industrial sources were summarized, and these data will be useful for developing an integrated emission inventory of PCBs.
    Chemosphere 12/2012; · 3.14 Impact Factor
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    ABSTRACT: Secondary copper production has received much attention for its high emissions of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) reported in previous studies. These studies focused on the estimation of total PCDD/F and polychlorinated biphenyl (PCB) emissions from secondary copper smelters. However, large variations in PCDD/F and PCB emissions reported in these studies were not analyzed and discussed further. In this study, stack gas samples at different smelting stages (feeding-fusion, oxidation and deoxidization) were collected from four plants to investigate variations in PCDD/F and PCB emissions and characteristics during the secondary copper smelting process. The results indicate that PCDD/F emissions occur mainly at the feeding-fusion stage and these emissions contribute to 54-88% of the total emissions from the secondary copper smelting process. The variation in feed material and operating conditions at different smelting stages leads to the variation in PCDD/F emissions during the secondary copper smelting process. The total PCDD/F and PCB discharge (stack gas emission+fly ash discharge) is consistent with the copper scrap content in the raw material in the secondary copper smelters investigated. On a production basis of 1ton copper, the total PCDD/F and dl-PCB discharge was 102, 24.8 and 5.88μgTEQt(-1) for the three plants that contained 100%, 30% and 0% copper scrap in their raw material feed, respectively.
    Chemosphere 10/2012; · 3.14 Impact Factor
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    ABSTRACT: Nine typical waste incinerating plants were investigated for polychlorinated naphthalene (PCN) contents in their stack gas. The incinerators investigated include those used to incinerate municipal solid, aviation, medical, and hazardous wastes including those encountered in cement kilns. PCNs were qualified and quantified by isotope dilution high resolution gas chromatography-high resolution mass spectrometry techniques. An unexpectedly high concentration of PCNs (13,000 ng Nm(-3)) was found in the stack gas emitted from one waste incinerator. The PCN concentrations ranged from 97.6 to 874 ng Nm(-3) in the other waste incinerators. The PCN profiles were dominated by lower chlorinated homologues, with mono- to tetra-CNs being the main homologues present. Furthermore, the relationships between PCNs and other unintentional persistent organic pollutants involving polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, hexachlorobenzene, and pentachlorobenzene were examined to ascertain the closeness or otherwise of their formation mechanisms. A good correlation was observed between ΣPCN (tetra- to octa-CN) and ΣPCDF (tetra- to octa-CDF) concentrations suggesting that a close relationship may exist between their formation mechanisms. The results would provide an improved understanding of PCN emissions from waste incinerators.
    Environmental Science and Pollution Research 09/2012; · 2.76 Impact Factor

Publication Stats

111 Citations
94.02 Total Impact Points

Institutions

  • 2014
    • Chinese Academy of Sciences
      • State Key Laboratory of Environmental Chemistry and Ecotoxicology
      Peping, Beijing, China
  • 2013–2014
    • Hong Kong Baptist University
      Chiu-lung, Kowloon City, Hong Kong
  • 2009–2013
    • Northeast Institute of Geography and Agroecology
      • • State Key Laboratory of Environmental Chemistry and Ecotoxicology
      • • Research Center for Eco-Environmental Sciences
      Beijing, Beijing Shi, China