Exploring the abundance and influencing factors of antimicrobial resistance genes in manure plasmidome from swine farms

Plasmids play a critical role in the dissemination of antimicrobial resistance genes (ARGs), however, a systematical understanding of ARGs originated from plasmids in swine production is currently lacking. Herein, quantitative polymerase chain reaction was applied to determine the prevalence of ten ARGs and the class1 integron gene intI1 of plasmid source in swine manure from 44 farms in Sichuan, Hubei and Hebei provinces, China. All assayed ARGs were observed in plasmid DNA samples, and the average absolute abundance of aac(6’)-Ib-cr, bla_NDM, bla_CTX-M, optrA, ermB, floR, mcr-1, qnrS, tetM, sul1 and intI1 were 7.09, 2.90, 4.67, 6.62, 7.55, 7.14, 4.08, 4.85, 7.16, 7.11 and 8.07 of 10 log copies/gram, respectively. IntI1 showed a high correlation (r > 0.8, P < 0.01) with the abundance of aac(6’)-Ib-cr and sul1 in swine manure. Moreover, the farm scale (i.e., herd population) and geographical location were not found to be critical factors influencing the absolute abundance of ARGs of plasmid DNA in swine farms. However, the concentrations of florfenicol, Cu, Zn, Fe, total phosphorus (TP) and total potassium (TK) demonstrated a significant correlation with the abundance of several ARGs. Particularly, Cu and Zn had high correlations with optrA and bla_CTX-M, respectively. Our results demonstrated that antibiotics, heavy metals and environmental nutrients are likely jointly contributing to the long-term persistence of ARGs in swine production. This study provides insights into the abundance and influencing factors of ARGs from swine manure, which is of significance for assessing and reducing the public health risks in livestock production.     

Electrically enhanced photodegradation of an azodye(Acid Orange Ⅱ) using a Pt/TiO2 film electrode irradiating with an UV lamp

A photoelectrochemical process in the degradation of an azodye(Acid Orange II)on a Pt/TiO2 film electrode was investigated.By using the glass device and the voltage stabilized source of direct current,decolorization ratios higher than 78% were observed during a period of 5h.Comparing this value with the sum of the decolorization ratios obtained by a sole application of electrochemical(lower than 3%)and photochemical(about 23%)procedures, a significant synergic effect between both processes was observed.The effects of adscititious voltage and pH value on the decolorization ratios were obvious while the effect of the amount of aeration was minor.     

昆明红壤环境下酸沉降对二种树木生长的影响

将昆明红壤人工酸化后进行树木生长实验。发现昆明红壤的酸缓冲能力非常大。在 12 0meqH /Lsoil的酸添加处理区也没有发现树木生长的显著下降。根据实际情况判断 ,认为没有必要继续加大酸添加强度进行实验     

沙堆实验研究三峡库区典型水域环境的水华污染行为

基于自组织临界性理论，设计和实施了具有真实物理意义的沙堆实验，结合三峡库区典型流域多年来富营养污染和水华爆发的现场监测资料，研究了缓流水系综合营养指数的变化趋势，描述了水华爆发／消退过程的自组织临界性行为。将沙堆实验统计数据中符合自组织临界性规律的普适性因子：沙堆底盘直径D、沙粒长度三、沙粒半径r和沙粒密度ρ等，与富营养污染流域中导致水华爆发的非线性耗散型控制函数相关联，从而有可能通过不同情况下沙堆崩塌的难易程度、频度和规模来发现、描述和确定水华爆发的内在机制和演化过程。沙堆实验的数值分析结果与这些典型流域水华发生过程的周期振荡行为和变化规律具有较好的一致性。     

曝气生态滤池中微生物群落组成及物种多样性

为研究曝气生态滤池滤料表面物种多样性及其净水机理,通过高通量测序和生物信息分析对曝气生态滤池（EAF）中2种填料的不同DO区域微生物丰度和多样性进行研究和分析.结果表明,在EAF运行过程中,变形菌门所占比例均在71%以上,具有绝对优势,优势菌群的大量增殖使装置具有较高的TN去除率（67%）,其中好氧区海绵铁表面样本优势菌群比例最高,达到77.49%,表明海绵铁在曝气条件下更适合优势菌群变形菌门的繁殖;Alpha多样性分析发现EAF内填料表面生物膜中微生物菌落丰度均高于空白样,表明EAF较自然环境更适合微生物生长;Beta多样性分析发现装置由于曝气使优势菌群变形菌门在填料表面大量繁殖,限制了其他菌种繁殖,虽然生物多样性略有降低,但随着优势菌群大量增殖从而提升了对TN的去除能力.     

Characterization of a new smog chamber for evaluating SAPRC gas-phase chemical mechanism

A new state-of-the-art indoor smog chamber facility (CAPS-ZJU) has been constructed and characterized at Zhejiang University, which is designed for chemical mechanism evaluation under well-controlled conditions. A series of characterization experiments were performed to validate the well-established experimental protocols, including temperature variation pattern, light spectrum and equivalent intensity (J_NO2), injection and mixing performance, as well as gases and particle wall loss. In addition, based on some characterization experiments, the auxiliary wall mechanism has been setup and examined. Fifty chamber experiments were performed across a broad range of experimental scenarios, and we demonstrated the ability to utilize these chamber data for evaluating SAPRC chemical mechanism. It was found that the SAPRC-11 can well predict the O₃ formation and NO oxidation for almost all propene runs, with 6 hr Δ(O₃ – NO) model error of –3% ± 7%, while the final O₃ was underestimated by ~20% for isoprene experiments. As for toluene and p-xylene experiments, it was confirmed that SAPRC-11 has significant improvement on aromatic chemistry than earlier version of SAPRC-07, although the aromatic decay rate was still underestimated to some extent. The model sensitivity test has been carried out, and the most sensitive parameters identified are the initial concentrations of reactants and the light intensity as well as HONO offgasing rate and O₃ wall loss rate. All of which demonstrated that CAPS-ZJU smog chamber could derive high quality experimental data, and could provide insights on chamber studies and chemical mechanism development.     

Investigation of volatile methyl siloxanes in biogas and the ambient environment in a landfill

Landfill biogas is a potential alternative for fossil fuel,but the containing impurities,volatile methyl siloxanes(simplified as siloxanes),often cause serious problems in gas turbines when applied to generate electricity.In this research,a collecting and analyzing method based on solvent adsorption and purge and trap-gas chromatography-mass spectrometry was established to determine the siloxanes in biogas from a landfill in Jinan,China,and adjacent ambient samples,such as soil,air,and leachate of the landfill.The results showed that,octamethylcyclotetrasiloxane(D4) and decamethylcyclopentasiloxane(D5) accounted for 63% of total siloxanes;and without considering D4 and D5,the order of detected siloxanes in concentration was found relating to Gibbs free energies of molecules,namely that higher abundant siloxane(except for D4 and D5) usually had lower Gibbs free energy.Additionally,the mass ratio between D4 and octamethyltrisiloxane(L3) in the bio gas varied with different garbage age in landfills,possibly revealing the breaking-down of larger siloxane molecules with time.The samples,which were collected from environmental samples adjacent to the landfill,such as soil,water,and air,presented much higher siloxane level than urban or rural area away from landfills.The current H2 S scrubber of the landfill biogas could decrease the total siloxanes from 10.7 to 5.75 mg/m~3 due to Fe2 O3 and a refrigerant drier in a purification system and cyclic siloxanes were more easily removed than linear ones.     

Carbon reduction potential and cost evaluation of different mitigation approaches in China's coal to olefin Industry

Coal-based olefin (CTO) industry as a complement of traditional petrochemical industry plays vital role in China's national economic development. However, high CO₂ emission in CTO industry is one of the fatal problems to hinder its development. In this work, the carbon emission and mitigation potentials by different reduction pathways are evaluated. The economic cost is analyzed and compared as well. According to the industry development plan, the carbon emissions from China's CTO industry will attain 189.43 million ton CO₂ (MtCO₂) and 314.11 MtCO₂ in 2020 and 2030, respectively. With the advanced technology level, the maximal carbon mitigation potential could be attained to 15.3% and 21.9% in 2020 and 2030. If the other optional mitigation ways are combined together, the carbon emission could further reduce to some extent. In general, the order of mitigation potential is followed as: feedstock alteration by natural gas > CO₂ hydrogenation with renewable electricity applied > CCS technology. The mitigation cost analysis indicates that on the basis of 2015 situation, the economic penalty for feedstock alteration is the lowest, ranged between 186 and 451 CNY/tCO₂, and the cost from CCS technology is ranged between 404 and 562 CNY/tCO₂, which is acceptable if the CO₂ enhanced oil recovery and carbon tax are considered. However, for the CO₂ hydrogenation technology, the cost is extremely high and there is almost no application possibility at present.     

Characterization of VOC emissions from construction machinery and river ships in the Pearl River Delta of China

Speciated characterization of Volatile Organic Compounds (VOCs), including oxygenated VOCs (OVOCs), from construction machinery and river ships in China is currently lacking. In this regard, we conducted field measurement on speciated VOC (including OVOC) emissions from six construction machinery and five river ships in the Pearl River Delta (PRD) region to identify VOC emission characteristics. We noticed that OVOC emissions from construction machinery and ships accounted for more than 50% of the total VOC emissions, followed by alkenes, aromatics and alkanes. Formaldehyde and acetaldehyde were the most emission species, accounting for 61.8%-83.2% of OVOCs. For construction machinery, the fuel-based emission factors of roller, grader and pile driver were 3.12, 3.12 and 7.36 g/kg, respectively. With the rigorous restraint by the national emission standards, VOC emissions of construction machinery had decreased considerably, especially during stage Ⅲ. Ozone formation potential was also significantly reduced due to the significant decrease in emissions of OVOCs and alkenes with higher reactivity. For river ships, the fuel-based emission factors of cargo ships and speedboat were 1.46 and 0.44 g/kg, respectively. VOC emissions from construction machinery and river ships in Guangdong Province in 2017 were 8851.0 and 4361.0 ton, respectively. This study filled the knowledge gaps of reactive gas emissions from different kinds of non-road mobile sources over the PRD, and more importantly, highlighted the necessity in adding OVOC measurement to give a complete and accurate depiction of reactive gas emissions from non-road mobile sources.     

滤池滤料上细菌数的预处理方法优化

为优化生物活性炭滤池活性炭上细菌数的流式细胞术定量分析的预处理方法,本研究考察了4种物理预处理方式（机械振荡、低能量超声、高能量超声、机械振荡耦合高能量超声）以及4种化学预处理方式（含10%的柠檬酸（Citric Acid,CA）和2.5%的羟基乙酸（Glycolic acid,GA）混合液（CA+GA）、溶菌酶、吐温20、乙二胺四乙酸）对流式细胞术测定活性炭滤料上细菌数的影响,结果表明,在无菌超纯水为提取液时,机械振荡耦合高能量超声预处理后测定的细菌数最高（9.7（±1.2）×10⁷ cells·g^-1（以WW活性炭计,下同））,是最佳的物理预处理方式.0.1% CA+GA为最优的化学分散剂,耦合机械振荡与1次高能量超声预处理后细胞累积回收率较空白组（无菌超纯水）提高了21%±17%,其活细菌数也最高（约1.0×10⁷ cells·g^-1）;耦合机械振荡与3次高能量超声预处理后,分离的生物膜细菌量最高（1.5（±0.2）×10⁸ cells·g^-1）,证明0.1% CA+GA耦合机械振荡与3次高能量超声是利用流式细胞术测定活性炭生物膜的细菌数的最佳预处理方式.