Continuous measurement of peroxyacetyl nitrate (PAN) in suburban and remote areas of western China

Knowledge on atmospheric abundance of peroxyacetyl nitrate (PAN) is important in assessing the severity of photochemical pollution, and for understanding chemical transformation of reactive odd nitrogen and its impact on the budget of tropospheric ozone (O₃). In summer 2006, continuous measurements of PAN were made using an automatic GC–ECD analyzer with an on-line calibrator at a suburban site of Lanzhou (LZ) and a remote site of Mt. Waliguan (WLG) in western China, with concurrent measurements of O₃, total reactive nitrogen (NO_y) and carbon monoxide (CO). At LZ, several photochemical episodes were observed during the study, and the average mixing ratio of PAN (plus or minus standard deviation) was 0.76 (±0.89) ppbv with the maximum value of 9.13 ppbv, compared to an average value of 0.44 (±0.16) ppbv at remote WLG. The PAN mixing ratios in LZ exhibited strong diurnal variations with a maximum at noon, while enhanced concentrations of PAN were observed in the evening and a minimum in the afternoon at WLG. The daily O₃ and PAN concentration maxima showed a strong correlation (r² = 0.91) in LZ, with a regression slope (PAN/O₃) of 0.091 ppbv ppbv^?1. At WLG, six well-identified pollution plumes (lasting 2–8 h) were observed with elevated concentrations of PAN (and other trace gases), and analysis of backward particle release simulation shows that the high-PAN events at WLG were mostly associated with the transport of air masses that had passed over LZ.     

土壤渗滤对有机微污染物去除性能研究

采用土壤柱试验研究了土壤渗滤对再生水中有机微污染物的去除性能。结果表明，土壤柱对再生水中的DOC、UV₂₅₄、总氮和总磷有较好的去除效果，并具有较高的抗冲击负荷的能力；土壤表层10 cm厚度对DOC的去除起主要作用；UV₂₅₄和AOX在土壤表层10 cm厚度降解效果不明显，随着深度增加去除率逐渐升高；液相色谱有机碳探测(LC-OCD)检测结果表明，土壤柱对溶解性有机物质的去除主要体现在对多糖物质的降解上，其次是有机酸类，对腐殖质也有一定的去除作用。     

Variation in Vegetation Structure and Soil Properties, and the Relation Between Understory Plants and Environmental Variables Under Different Phyllostachys pubescens Forests in Southeastern China

Biodiversity maintenance and soil improvement are key sustainable forestry objectives. Research on the effects of bamboo forest management on plant diversity and soil properties are therefore necessary in bamboo-growing regions, such as southeastern China’s Shunchang County, that have not been studied from this perspective. We analyzed the effects of different Phyllostachys pubescens proportions in managed forests on vegetation structure and soil properties using pure Cunninghamia lanceolata forests as a contrast, and analyzed the relation between understory plants and environmental variables (i.e., topography, stand and soil characteristics) by canonical correspondence analysis (CCA). The forest with 80% P. pubescens and 20% hardwoods (such as Phoebe bournei, Jatropha curcas, Schima superba) maintained the highest plant diversity and best soil properties, with significantly higher plant diversity than the C. lanceolata forest, and better soil physicochemical and biological properties. The distribution of understory plants is highly related to environmental factors. Silvicultural disturbance strongly influenced the ability of different bamboo forests to maintain biodiversity and soil quality under extensive management, and the forest responses to management were consistent with the intermediate-disturbance hypothesis (i.e., diversity and soil properties were best at intermediate disturbance levels). Our results suggest that biodiversity maintenance and soil improvement are important management goals for sustainable bamboo management. To achieve those objectives, managers should balance the inputs and outputs of nutrients and protect understory plants by using appropriate fertilizer (e.g., organic fertilizer), adjusting stand structure, modifying utilization model and the harvest time, and controlling the intensity of culms and shoots harvests.     

油气田建设项目施工期环境监理探析

针对油气田建设项目的具体情况,对油气田建设项目施工期主要环境影响,包括钻井作业、输气站及输气管道建设工程中的主要环境影响进行了分析,从施工期的污染防治措施监理、生态保护措施监理、环境保护设施监理几个方面对施工期环境监理的主要内容进行了探讨。     

论信息产业与可持续发展

信息产业与可持续发展在共同的时代背景下应运而生,相互作用又有机统一.信息产业对可持续发展有显著的正效应,主要表现为:信息产业对经济发展的贡献;信息技术的发展应用,可以减少人物流动,提高资源配置效率;合理利用自然资源,实时监测环境变化;可以通过非物质化降低能耗和物耗,等等.同时,信息产业因其固有的特殊性,又表现出与可持续发展不协调的方面,如信息安全与信息污染、电子产品中有毒元素的应用、电磁辐射及对人体的影响等.文章最后提出,信息产业对社会经济的可持续发展具有重要的推动作用,大力发展信息产业是我国产业结构调整的必然选择,以可持续发展战略指导信息产业健康发展,并以信息产业推动其他行业的可持续发展,提高资源环境利用和管理水平,是可持续发展的必由之路.     

聚合物驱采出水中聚丙烯酰胺的微生物联合降解作用研究

通过对2株细菌的培养降解实验研究聚丙烯酰胺(hydrolyzed polyacrylamide,HPAM)降解菌对水环境下聚丙烯酰胺的降解作用,讨论协同降解机理。2株降解聚丙烯酰胺的菌株假单胞菌CJ419、枯草芽孢杆菌FA16在初始30℃废水样品上培养,定期测量细菌生物量和HPAM降解率。培养30 d后CJ419和FA16对聚合物的降解率最大值分别达到30.4%和25%,而以1∶1比例的混合菌降解率最大值达到80.3%。对2株菌胞外各组分研究表明:混合菌降解HPAM的机理主要由胞外降解酶系水解聚合物侧链基团导致HPAM降解为小分子物质,同时生长过程中降解菌还会释放非蛋白还原性物质引发氧化反应共同参与HPAM降解。     

植物配置对表层流湿地净化效果的影响研究

以郑州市贾鲁河河水为处理对象,研究了不同植物配置表层流湿地的水质净化效果及影响因素。研究表明,单纯挺水植物湿地对TN、TP、NH4+-N和COD的平均去除率分别为28%、58%、49%和26%;采用沉水植物+浮叶植物+挺水植物组合的湿地对TN、TP、NH4+-N和COD的平均去除率分别为37%、64%、63%和32%,在对NH4+-N和TN的处理效果上表现出明显的优势,DO含量变化是导致处理效果差异的主要原因。研究结果表明,在湿地植物配置上,可从氮循环的角度,通过合理搭配湿地植物,强化硝化反硝化作用,以提高对氮素的去除效果。     

Cornmeal-induced resistance to ciprofloxacin and erythromycin in enterococci

Triclosan is used as an antibacterial agent in household items and personal care products. Since this compound is found in maternal milk of humans and bodies of wild animals, there is growing concern among some consumer groups and scientific community that triclosan is adverse for humans and wild animals. In order to estimate adverse actions of triclosan, the effects of triclosan on intracellular Zn²⁺ concentration and cellular thiol content were studied in rat thymocytes by the use of flow cytometer with appropriate fluorescent probes. Triclosan at 1-3 μM (sublethal concentrations) increased the intensity of FluoZin-3 fluorescence (intracellular Zn²⁺ concentration) and decreased the intensity of 5-chloromethylfluorescein (5-CMF) fluorescence (cellular thiol content). Negative correlation (r = −0.985) between triclosan-induced changes in FluoZin-3 and 5-CMF fluorescences was found. Removal of external Zn²⁺ did not significantly affect the triclosan-induced augmentation of FluoZin-3 fluorescence, suggesting an intracellular Zn²⁺ release by triclosan. These actions of triclosan were similar to those of H₂O₂ and triclosan significantly potentiated the cytotoxicity of H₂O₂. Therefore, the results may suggest that triclosan at sublethal concentrations induces oxidative stress that decreases cellular thiol content, resulting in an increase in intracellular Zn²⁺ concentration by Zn²⁺ release from intracellular store(s). Since recent studies show many physiological roles of intracellular Zn²⁺ in cellular functions, the triclosan-induced disturbance of cellular Zn²⁺ homeostasis may induce adverse actions on the cells.     

水稻与棉花秸秆不同预处理厌氧发酵产沼气

以猪粪为接种物,以棉花秸秆和水稻秸秆为发酵原料,分别对秸秆进行稀碱法预处理和稀碱法与超声波联合预处理,在发酵温度为(37±1)℃的条件下进行厌氧发酵产沼气的研究。结果表明,以联合预处理的秸秆为发酵原料,厌氧发酵的各项指标均比以稀碱预处理秸秆发酵的效果好,其中累积产气量和沼气中甲烷含量分别提高35.23%和2.4%,发酵后TS、VS含量相对减少2.6%～10.94%,发酵液代谢产物中的有机酸丙酮酸、乙酸和柠檬酸含量相对减少23.9%～25.9%、20.24%～24.53%和41.08%～45.91%。     

Fenton法处理垃圾渗滤液MBR-NF浓缩液

采用Fenton法处理MBR-NF浓缩液,考察了FeSO4·7H2O投加量、n(H2O2)/n(Fe2+)投加比、初始pH对渗滤液MBR-NF浓缩液处理效果的影响,并在最佳实验条件下,探讨浓缩液富里酸(FA)、亲水性有机物(HyI)组分在Fenton氧化前后组成的变化。研究结果表明,在FeSO4·7H2O投加量为0.055 mol/L、n(H2O2)/n(Fe2+)投加比为4、初始pH为7.58时,对COD、腐植酸(UV254)、色度(CN)的去除率分别为79.6%、93.7%和97.8%。Fenton氧化后,浓缩液中有机物组分含量发生了较大变化,腐植酸含量下降,HyI成为渗滤液溶解性有机物主要成分。紫外-可见光谱表明,Fenton法对FA去除效果较好,而对HyI氧化效果较差;傅立叶红外光谱显示,经Fenton氧化后,FA的结构发生了明显变化,而HyI则变化不明显。