Differential responses of short-term soil respiration dynamics to the experimental addition of nitrogen and water in the temperate semi-arid steppe of Inner Mongolia, China

We examined the effects of simulated rainfall and increasing N supply of different levels on CO2 pulse emission from typical Inner Mongolian steppe soil using the static opaque chamber technique, respectively in a dry June and a rainy August. The treatments included NH4NO3 additions at rates of 0, 5, 10, and 20 g N/（m2.year） with or without water. Immediately after the experimental simulated rainfall events, the CO2 effluxes in the watering plots without N addition （WCK） increased greatly and reached the maximum value at 2 hr. However, the efflux level reverted to the background level within 48 hr. The cumulative CO2 effluxes in the soil ranged from 5.60 to 6.49 g C/m2 over 48 hr after a single water application, thus showing an increase of approximately 148.64% and 48.36% in the efftuxes during both observation periods. By contrast, the addition of different N levels without water addition did not result in a significant change in soil respiration in the short term. Two-way ANOVA showed that the effects of the interaction between water and N addition were insignificant in short-term soil COz efftuxes in the soil. The cumulative soil CO2 fluxes of different treatments over 48 hr accounted for approximately 5.34% to 6.91% and 2.36% to 2.93% of annual C emission in both experimental periods. These results stress the need for improving the sampling frequency after rainfall in future studies to ensure more accurate evaluation of the grassland C emission contribution.     

程序升温微波辐照法解吸活性炭上吸附的甲苯

利用微波辐照作为加热手段,采用程序升温的方法对活性炭上吸附的甲苯进行解吸。程序升温条件为：初始温度及升温幅度为100℃,每个温度点保持10min,终温500℃保持5min。实验结果表明,程序升温解吸45min,甲苯解吸率达91％。程序升温和400℃恒温微波辐照解吸两种方法对比发现,甲苯解吸率达90％的时间基本相当,但程序升温解吸的能量消耗更小,能量利用率更高。     

电脱盐废水处理技术现状

近几年,随着原料油的劣质化、重质化、乳化严重,造成电脱盐装置在运行过程中乳化困难,从而导致原油电脱盐脱水合格率低。文章介绍了石油炼制企业电脱盐废水的概况和水质特点,针对原油性质恶化、原油预沉降处理时间不够和石油炼制工艺差异三个因素,分析了其对电脱盐废水的盐含量、金属离子含量、酸值、胶质沥青质含量、乳化程度等水质水量特征的影响。介绍了目前电脱盐废水处理技术的进展,结合几个典型炼化企业电脱盐废水处理工艺应用现状,展望了电脱盐废水处理技术的发展趋势。     

One century sedimentary record of lead and zinc pollution in Yangzong Lake, a highland lake in southwestern China

Reconstruction of trace metal pollution histories and sources may help us to regulate current pollutant discharge. This is especially important for the highland lakes in southwestern China, which are facing trace metals pollution. We present sedimentary records of 11 metals accumulated in Yangzong Lake since the 1870's, a highland lake in southwestern China. Pollution of lead and zinc (Pb and Zn) was differentiated based on principal component analysis, geochemical normalization, and lead isotope ratios. Nearly all the metals as well as grain size composition show generally constant values before the mid-1980's, denoting stable detrital input in the catchment. Fluctuations in the concentrations of the metals as well as grain size composition since the mid-1980's indicate an increase in soil erosion with strengthened human disturbance in the catchment. After geochemical normalization, Pb and Zn showed constant values before 1990 AD and then a gradual increase in parallel with the variations in ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁷Pb/²⁰⁶Pb ratios, indicating that Pb and Zn pollution occurred. Combining the data of ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁷Pb/²⁰⁶Pb ratios in the sediments of Yangzong Lake, leaded gasoline, Pb-Zn ore and coal, and consumption or production historical trends, we deduced that the enhanced Pb and Zn pollution in Yangzong Lake is caused primarily by ore mining and refining.     

BOD5容量计算的不确定性分析

应用蒙特卡罗方法对BODs容量计算的不确定性,作出定量估计。结合算例,讨论了主要参数的统计检验,随机变量生成等。给出了以容量——概率曲线估计不确定性的定量结果。     

新常态下亟需树立经济发展与环境保护“共生”观

从根本上解决环境问题,特别是在新常态下,需要建立经济发展与环境保护“共生”观。本文论述了经济与环境共生观产生的背景与内涵。贯彻经济发展与环境保护共生的观念,必须采取2个行动:一是改变环境保护实施综合决策体制,建立经济发展与环境保护融合决策体制。在最高决策层,要采取经济与环境融合决策体制,在这个背景下政策环境影响评价将顺利通过。二是改变经济发展与环境保护协调运行机制,建立经济发展与环境保护协同运行机制。京津冀等地协同治理雾霾取得了一定的成绩,说明树立经济与环境共生观念,建立协同运行机制是可行的。     

Molecular characterization of root exudates using Fourier transform ion cyclotron resonance mass spectrometry

The release of root exudates (REs) provides an important source of soil organic carbon. This work revealed the molecular composition of REs of different plant species including alfalfa (Medicago sativa L.), bean (Phaseolus vulgaris L.), barley (Hordeum vulgare L.), maize (Zea mays), wheat (Triticum aestivum L.), ryegrass (Lolium perenne L.) and pumpkin (Cucurbita maxima) using electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The combination of positive ion mode (+ESI) and negative ion mode (-ESI) increased the number of the molecules detected by ESI FT-ICR MS, and a total of 8758 molecules were identified across all the samples. In detail, lipids and proteins and unsaturated hydrocarbons were more easily detected in +ESI mode, while aromatic compounds with high O/C were readily ionized in -ESI mode, and only 38% of the total assigned formulas were shared by -ESI and +ESI modes. Multivariate statistical analysis of the formulas indicated that the close related plants species secreted REs with similar molecular components. Moreover, the unsaturation degree and nitrogen content were the two key parameters able to distinguish the similarities and differences of molecular components of REs between plant species. The results provided a feasible analysis method for characterization of the molecular components of REs and for the first time characterized the molecular components of REs of a variety of plant species using ESI FT-ICR MS.     

安庆地震台山洞再利用的可行性研究

本文全面总结了安庆台山洞的现状,客观指出安庆台山洞巳经不能满足现实需求,并依据地震监测规范要求,就如何改善和解决观测条件和观测系统等方面存在的问题,以实现山洞的再利用进行了深入研究和探讨,认为安庆台山洞可以通过观测环境的改造、观测系统的升级等措施实现山洞再利用,并能够重新发挥安庆台洞体观测在全省地震监测中的重要作用,同...     

BAF-BAC组合工艺对受污染河水水质净化研究

研究通过采用BAF-BAC组合工艺净化受污染河水,进行了该系统对主要污染物指标的去除效果分析,并结合多种生物毒性效应检测,进行了系统对生物毒性物质的去除研究。结果表明:组合工艺系统稳定运行阶段,对COD、NH3-N和TN平均去除率分别在60%、96%和19%左右。试验条件下最适宜水力负荷10 L/h,BAF单元最佳气水比为7:1时,系统对上述污染物的去除率分别达到72%、99%和20%。发光菌抑制试验表明,受污染河水在浓缩50、10和2倍时,相对抑制率均高于80%,经BAF-BAC组合装置净化后,相对抑制率分别为15.8%、7.8%和3%,出水水质没有表现出明显急性毒性特征;受污染河水对大型蚤急性致死率达到100%,而最终出水大型蚤死亡率为0%;在浓缩50倍、20倍、10倍和1倍时,受污染河水水样对仔鱼的致死性分别为100%、70%、20%和0,最终出水水样中仔鱼死亡率均为0,说明组合工艺系统各单元对此类毒性物质均有去除效果。