Future of global governance and climate change action in a changing political landscape

<正>1.Editor's note On 30 November 2016,the Brookings-Tsinghua Center for Public Policy(BTC),Caixin Video,and Columbia Global Centers(Beijing)jointly hosted a Seminar on the Future of Global Governance and Climate Change Action in a Changing Political Landscape.Leading experts on China's environmental policy and climate     

厦门市空气污染的空间分布及其与影响因素空间相关性分析

基于空间信息技术、克里格插值与空间相关矩阵,研究厦门市SO2、NO2、PM10和PM2.5污染浓度空间分布特征。通过提取人口密度、道路面积比重、建设用地比重、地表温度及植被指数等空气污染影响因素的空间分布数据,划分研究区为生态区、居住区与工业区,定量评价了污染物浓度与影响因素的空间相关性,并识别出各污染物的主要影响因素。结果表明:污染浓度分布总体上呈现出工业区-居住区-生态区递减的空间特征,其主要受工业排放和机动车排放的影响;SO2与除地表温度外的其他影响因数均有较强空间相关性,PM10和PM2.主要与道路面积比重、建设用地比重具有较强相关性,NO2则与道路面积比重的相关性最强,污染浓度与影响因数空间相关性呈现出工业区-居住区-生态区递增趋势;与按照行政区的划分相比,工业区、居住区、生态区的划分显得更为合理。     

Fenton试剂氧化法处理染料结晶废母液

采用Fenton试剂氧化法处理分散橙、分散紫和分散蓝3种染料结晶废母液。研究了H₂O₂加入量、n（H₂O₂）#x02236;n（Fe²⁺）和废母液pH对COD去除率或TOC去除率的影响。对TOC去除反应分段进行了动力学方程拟合,并探讨了反应机理。实验得到的分散橙、分散紫和分散蓝的废母液处理工艺条件：H₂O₂加入量分别为264.4,352.9,441.2mmol/L;n（H₂O₂）#x02236;n（Fe²⁺）分别为20,10,20;废母液pH=3。3种废母液在0~20min和20~120min两个阶段的反应与二级动力学拟合方程的相关性最好。3种废母液经Fenton试剂氧化处理后,部分有机物降解为小分子有机酸,部分有机物完全矿化。     

污泥膜覆盖好氧发酵堆体流场模拟及应用研究简

运用Gambit软件建立了污泥好氧发酵堆体的多孔介质模型,通过自行设计的实验装置获得了堆体的通风粘性阻力系数和惯性阻力系数以及功能膜压差与透气量之间的关系,用Fluent软件分析了堆体不同截面形状及底部通风管数量对堆体通风均匀性的影响,为确定合理的通风管数量及截面几何形状提供理论依据。对上海奉贤区城镇污水厂污泥处理工程发酵仓进行堆体流场模拟,确定堆体采用小拱形截面形状,堆高2 m,宽8 m,底部设置4条通风管,实际运行效果良好。     

Dioxin-like activity in sediments from Tai Lake, China determined by use of the H4IIE-luc bioassay and quantification of individual AhR agonists

Deterioration of the general ecosystem and specifically quality of the water in Tai Lake (Ch: Taihu), the third largest freshwater in China, is of great concern. However, knowledge on status and trends of dioxin-like compounds in Tai Lake was limited. This study investigated AhR-mediated potency and quantified potential aryl hydrocarbon receptor (AhR) agonists in sediments from four regions (Meiliang Bay, Zhushan Lake, Lake Center, Corner of Zhushan Lake, and Meiliang Bay) of Tai Lake by use of the in vitro H4IIE-luc, cell-based, transactivation, reporter gene assay, and instrumental analysis. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (Bio-TEQs) in sediments ranged from less than the limit of detection to 114.5 pg/g, dry weight, which indicated that organic extracts of sediments exhibited significant AhR-mediated potencies. Results of the potency balance analysis demonstrated that acid-labile, dioxin-like compounds represented a greater proportion of concentrations of Bio-TEQs in sediments from Tai Lake. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents calculated as the sum of the product of concentrations of individual congeners and their respective relative potencies (Chem-TEQs) based on polycyclic aromatic hydrocarbons and/or polychlorinated biphenyls represented no more than 10 % of the total concentrations of Bio-TEQs.     

Characterization of the interactions between tetracycline antibiotics and microbial extracellular polymeric substances with spectroscopic approaches

The antibiotics have attracted global attentions for their impact on aquatic ecosystem. The knowledge about the fate of antibiotics encountering extracellular polymeric substances (EPS) is, however, limited. In this study, we investigated the interacting mechanisms of tetracycline (TC) to EPS extracted from aerobic activated sludge. The contributions of the main components of EPS, extracellular proteins, and polysaccharides were evaluated using bovine serum albumin and alginate sodium, respectively. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance indicated that hydroxyl, carboxyl, and amino groups were the domain chemical groups involved in the interaction between TC and EPS, and the binding of TC onto EPS changed the structure of these chemical groups, thus causing shifts in their UV–visible absorption spectra. In addition, we found that extracellular proteins, rather than polysaccharides, were the major active contents involved in the interaction. Three-dimensional excitation–emission matrix fluorescence spectroscopy showed that the fluorophores in EPS were clearly quenched by TC and the static quenching process was observed, implying the complex formation of TC and EPS. Furthermore, thermodynamic analysis indicated that the binding of TC with EPS is spontaneous and dominated by electrostatic forces.     

Manganese concentrations in maternal–infant blood and birth weight

Manganese (Mn) is an essential mineral nutrient in mammals. The physiological role of Mn in animal models is well documented, but little is known about the adverse effects of Mn deficiency or overexposure in humans, including pregnancy outcomes such as birth weight. We examined the relationship of the maternal and cord blood Mn levels with birth weight in a cohort of 172 mother–infant pairs born in Shanghai, China. Non-linear spline and quadratic regression models were used to test the hypothesis of an inverted U-shaped association between the Mn levels and birth weight. The median (range) levels of Mn in the maternal and cord blood were 5.38 (2.34–30.37) μg/dL and 7.66 (2.57–34.23) μg/dL, respectively. An inverted U-shaped relationship was observed between maternal Mn and birth weight after adjusting for potential confounders. The birth weight increased with Mn levels up to 4.18 μg/dL, and a slight reduction in weight was observed at higher levels. The cord blood Mn levels were not found to be associated with birth weight. Both lower and higher Mn exposures are associated with lower birth weight, which may influence important developmental parameters; the association of higher Mn levels with lower weight was weak and imprecise.     

Positive matrix factorization as source apportionment of soil lead and cadmium around a battery plant (Changxing County,China)

Chemical compositions of soil samples are multivariate in nature and provide datasets suitable for the application of multivariate factor analytical techniques. One of the analytical techniques, the positive matrix factorization (PMF), uses a weighted least square by fitting the data matrix to determine the weights of the sources based on the error estimates of each data point. In this research, PMF was employed to apportion the sources of heavy metals in 104 soil samples taken within a 1-km radius of a lead battery plant contaminated site in Changxing County, Zhejiang Province, China. The site is heavily contaminated with high concentrations of lead (Pb) and cadmium (Cd). PMF successfully partitioned the variances into sources related to soil background, agronomic practices, and the lead battery plants combined with a geostatistical approach. It was estimated that the lead battery plants and the agronomic practices contributed 55.37 and 29.28 %, respectively, for soil Pb of the total source. Soil Cd mainly came from the lead battery plants (65.92 %), followed by the agronomic practices (21.65 %), and soil parent materials (12.43 %). This research indicates that PMF combined with geostatistics is a useful tool for source identification and apportionment.     

Characterization of the extracellular biodemulsifiers secreted by Bacillus cereus LH-6 and the enhancement of demulsifying efficiency by optimizing the cultivation conditions

A highly efficient demulsifying strain, LH-6, was isolated from petroleum-contaminated soil and identified as Bacillus cereus by 16S rDNA gene analysis. It achieved 95.61 and 95.40 % demulsifying ratios within 12 h for water-in-oil (W/O) and oil-in-water (O/W) model emulsions, respectively. Fourier transform infrared spectroscopy (FT-IR) and thin-layer chromatography (TLC) detections indicated that the LH-6’s extracellular biodemulsifiers were different types of lipopeptides for the W/O and O/W emulsions. Optimization of the culture medium composition was conducted to improve the biosynthesis and demulsifying efficiency of the biodemulsifier. The optimal carbon source was liquid paraffin, while waste frying oil could also be an alternative carbon source. The optimal nitrogen sources were ammonium sulfate and yeast extract. To further enhance the biodemulsifier efficiency, the optimal cultivation conditions were determined using response surface methodology (RSM) based on central composite rotation design (CCRD). Using the optimized cultivation conditions, the demulsifying ratios increased to 98.23 and 97.65 % for the W/O and O/W model emulsions, respectively.     

磷石膏水热法合成硫酸钙晶须

以磷石膏为原料,二水合硫酸钙、硫酸镁、甘油为添加剂,采用水热法合成硫酸钙晶须,考察了料浆含量、反应温度、反应时间、体系pH等因素对晶须的直径和长径比的影响;并采用SEM技术观察硫酸钙晶须的形貌。实验结果表明,当磷石膏含量2.5%（w）、反应温度130 ℃、反应时间4 h、体系pH 4时,制备得到的硫酸钙晶须长径比为56.24,平均直径为0.17 μm。SEM表征结果显示,硫酸钙晶须形貌规整、分散均匀、直径较小,达百纳米级。