砷浓度、形态及碳酸氢盐对蜈蚣草吸收砷的影响

为了探讨超富集植物蜈蚣草在处理高砷地下水方面的可行性,研究了水培条件下砷的浓度、形态和碳酸氢盐(HCO-3)对超富集植物蜈蚣草吸收砷的影响。实验中使用了浓度为0.1～100mg·L-1的As(III)和As(V)溶液。HCO-3处理中,HCO-3浓度范围为0.5～20mmol·L-1,As(III)或As(V)的浓度为5mg·L-1。结果表明,在水培条件下,蜈蚣草具有明显的耐高砷特征。当介质砷含量高达100mg·L-1时,砷的去除率可达到80%,且对As(III)的吸收效率高于As(V)。植物体内砷形态研究表明,蜈蚣草体内2种形态砷的含量与外源砷形态有一定的关系,As(V)处理条件下,植物体中的As(V)比例较As(III)处理高。高浓度的HCO-3(20mmol·L-1)处理对蜈蚣草地上部分生物量没有明显影响,但是抑制了地下部分的生长,并且对砷的吸收表现出明显的抑制作用。     

Size-resolved aerosol ionic composition and secondary formation at Mount Heng in South Central China

To understand the size-resolved aerosol ionic composition and the factors influencing secondary aerosol formation in the upper boundary layer in South Central China, size-segregated aerosol samples were collected using a micro-orifice uniform deposit irnpactor （MOUDI） in spring 2009 at the summit of Mount Heng （1269 m asl）, followed by subsequent laboratory analyses of 13 inorganic and organic water-soluble ions. During non- dust-storm periods, the average PM1.8 concentration was 41.8 μg·m^-3, contributing to 55% of the PM10. Sulfates, nitrates, and ammonium, the dominant ions in the fine particles, amounted to 46.8% of the PM1.8. Compared with Mount Tai in the North China Plain, the concentrations of both fine and coarse particles and the ions contained therein were substantially lower. When the air masses from Southeast Asia prevailed, intensive biomass burning there led to elevated concentrations of sulfates, nitrates, ammonium, potassium, and chloride in the fine particles at Mount Heng. The air masses originating from the north Gobi brought heavy dust storms that resulted in the remarkable production of sulfates, ammonium, methane sulfonic acid, and oxalates in the coarse particles. Generally, the sulfates were primarily produced in the form of （NH4）2SO4 in the droplet mode via heterogeneous aqueous reactions. Only approximately one-third of the nitrates were distributed in the fine mode, and high humidity facilitated the secondary formation of fine nitrates. The heterogeneous formation of coarse nitrates and ammonium on dry alkaline dust surfaces was found to be less efficient than that on the coarse particles during non-dust-storm periods.     

Removal of Zn2+ from aqueous solution by biomass of Agaricus bisporus

Biosorption of Zn²⁺ from aqueous solutions by biomass of Agaricus bisporus was investigated. The removal rates of Zn²⁺ by A. bisporus under different parameters (e.g., solution pH, bio-sorbent dosage and initial Zn²⁺ concentration) were studied. The inhibition of A. bisporus’s biosorption by anionic ligands EDTA (Ethylene Diamine Tetraacetic Acid), acetate and citrate) implied that EDTA and citrate might be used as eluting reagents. Regular and simultaneous solution pH change and light metal ions release after biosorption indicated that an ion exchange mechanism was involved. From FT-IR (Fourier Transform Infrared) spectroscopy, the main functional groups participated in biosorption were found. Biosorption of Zn²⁺ by A. bisporus could be well described by the Freundlich and Langmuir models. In conclusion, the biomass of A. bisporus showed high potential for the treatment of wastewater containing Zn²⁺.     

成组生物毒性测试法综合评价典型工业废水毒性

为了更加准确地评估典型工业废水的综合生物毒性以及处理工艺对废水毒性的削减情况,采用发光细菌急性毒性实验、大型溞急性毒性实验和单细胞凝胶电泳实验,结合潜在生态毒性效应探测(potential ecotoxic effects probe,PEEP)指数对常州市7种典型工业废水的综合生物毒性进行了评价。结果表明,7种工业原水都表现出了急性毒性或遗传毒性,综合生物毒性强度的排序为电子厂>电镀厂>综合污水处理厂>印染厂>化工厂>食品厂>制药厂。而7种工业废水的处理后出水综合生物毒性强度的排序为印染厂>化工厂>电子厂>综合污水处理厂>食品厂>制药厂>电镀厂。其中,印染和化工厂出水综合生物毒性高于原水,分别增加了43.3%和38.7%,PEEP评价结果显示分别属于剧毒和高毒,而电镀、电子、综合污水处理和食品厂出水的综合生物毒性削减明显,分别比原水削减了76.9%、53.1%、48.3%和26.6%,PEEP结果表明基本无毒。建立在成组生物毒性实验基础上的PEEP评价方法可全面反映工业废水的综合生物毒性,进而更客观地评价废水对水生态系统乃至人类健康的潜在影响。     

Characterization of submicron aerosols in the urban outflow of the central Pearl River Delta region of China

Submicron aerosol particles (with aerodynamic diameters less than 1 μm, PM₁) were sampled and measured in Heshan, an urban outflow site of Guangzhou megacity in Pearl River Delta in South China, using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) in November 2010 during 2010 Guangzhou Asian Games. The mean PM₁ mass concentration measured was 47.9±17.0 μg·m^-3 during the campaign, with organic aerosol (OA) and sulfate being the two dominant species, accounting for 36.3% and 20.9% of the total mass, respectively, followed by black carbon (17.1%, measured by an aethalometer), nitrate (12.9%), ammonium (9.6%) and chloride (3.1%). The average size distributions of the species (except black carbon) were dominated by an accumulation mode peaking at ~550 nm. Calculations based on high-resolution organic mass spectrum showed that, C, H, O and N on average contributed 58.1%, 7.3%, 30.7%, and 3.9% to the total organic mass, respectively. The average ratio of organic mass over organic carbon mass (OM/OC) was 1.73±0.08. Four components of OA were identified by the Positive Matrix Factorization (PMF) analysis, including a hydrocarbon-like (HOA), a biomass burning (BBOA) and two oxygenated (SV-OOA and LV-OOA) organic aerosol components, which on average accounted for 18.0%, 14.3%, 28.8% and 38.9% of the total organic mass, respectively.     

基于计算智能的流域污染排放优化模式研究

基于人工神经网络和遗传算法建立了流域排污削减控制的技术框架.通过对排污口和目标断面水质监测数据的模拟与优化提出最优的排污削减控制策略,从而使目标功能区达标,可以间接的实现环境容量总量控制.结合情景分析理论对松花江哈尔滨段的朱顺屯-东江桥(S1)与东江桥-大顶子山(S2)功能区进行了COD的排污优化研究.结果表明,S1区段执行III类功能区标准时,何家沟与松北两个排污口平均削减率分别为23%和25%;执行II类功能区标准时2个排污平均削减率分别为64%和42%.S2执行II类功能区标准,太平,阿什河和呼兰河排污口全年平均削减率分别为18%、53%和25%.基于计算智能的削减控制模式实用可操作性强,可以科学、合理的对各个排污口源强进行优化,给出最优的污染排放策略.     

a-亚麻酸对赤潮异弯藻生长的抑制作用

探讨了a-亚麻酸对赤潮异弯藻(Heterosigma akashiwo)生长的抑制作用,并从细胞膜渗透性、抗氧化酶系和光合放氧量等方面研究了其抑制机理.结果表明,a-亚麻酸对赤潮异弯藻有明显的抑制作用,其第7d的IC50为2.4μL/L.在a-亚麻酸作用下,细胞内Na+、K+、Mg2+和Ca2+浓度随着实验的进行受到不同程度的影响,在36h后都出现明显的下降;藻细胞内可溶性蛋白质含量下降,超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT).在8h时明显高于对照组,之后逐渐下降,到36h时低于对照组;丙二醛含量(MDA)表征了脂质过氧化强度和膜系统受损程度,其在12h时明显高于对照组,之后慢慢下降;藻细胞的光合放氧量呈逐渐下降趋势.结果表明,a-亚麻酸通过改变细胞膜透性和自由基反应,从而破坏藻细胞的结构,进而达到抑藻的效果.     

水中痕量阿特拉津的测定方法研究

采用固相萃取与高效液相色谱结合的方法测定了水样中痕量阿特拉津的含量,研究了最佳固相萃取条件:选择洗脱液为乙腈,过样流速为5.0 mL/min。最佳的色谱条件:流动相为乙腈和水,温度为25℃,流速为1.0 mL/min,检测波长为222 nm。阿特拉津质量浓度在0.05～5 mg/L范围内线性关系良好,回归方程y=219.71x+2.2343,回收率平均值为98.46%,将该方法应用于实际环境水样的分析测定,操作简单,结果准确。     

Research and practice on fluctuation water injection technology at low permeability coal seam

In order to solve the problem of poor affusion effect on low permeability coal seam, the paper analyzes the micro process of the coal seam water infusion in wetting coal and determines the main factors affecting coal seam water infusion. The permeability of the NO.3 coal seam in east working face of Xingcun coal mine by MTS815.03 servo-controlled rock mechanical test system has been tested. Results show that when the peak stress in coal sample specimens reaches 48.53 MPa, permeability ranges from 0.5158 to 2.9576 × 10⁻⁸ Darcy, and it means that the coal seam is low in permeability and difficult in water injection. Based on the characteristics of low permeability and geostress situation, efficient fluctuation water injection technology with permeable agent and relevant process parameters have been designed. The surface tension of the permeable agent developed here is 31.18 m N/m when mass concentration reaches 0.05%. The permeable agent can permeate into 2 cm thick coal layer completely in 10 s, thus improving the wettability of water effectively and the water injection pressure fluctuates between 7 MPa and 25 MPa. The application of the technique in the 3rd coal seam in east working face of Xingcun coal mine shows not only single-arch injection experienced a significant increase on average, from no more than 10 m³ to 63.3886 m³, but also the effect of dust fall, cooling and rock burst prevention is remarkable.     

人工边坡破裂面的最短路径搜索方法及其应用

文章运用Dijkstra最短路径算法确定土体中最危险的潜在破裂面,通过弹塑性有限元模拟基坑开挖过程, 计算土体的位移和应力以及评价基坑的稳定性。文中较详细地叙述了这种基于有限元分析技术和组合优化法来确定土坡中最危险的潜在破裂面的原理和实施过程,并给出了计算实例,进行了相应的讨论。