厌氧暗发酵产氢细菌研究进展

厌氧暗发酵产氢细菌可在暗环境下分解有机物,产生氢气,在厌氧发酵制氢技术发展中发挥重要作用.对近年来国内外产氢细菌的分离、生理特性、产氢能力研究以及实际应用等方面的进展进行了综述,提出了目前产氢细菌研究存在的问题,认为应加强高效产氢细菌的分离、菌群间代谢网络构建以及弱化产氢过程中有机挥发酸的反馈抑制等方面的研究.     

利用工业废渣固化软土的试验研究

根据软土固化所需水化物组成的特殊性以及固化土结构形成过程的特点,有针对性地选择煤矸石、电石渣和磷石膏制备成以工业废渣为主要成分的软土固化剂。试验表明：采用合理的组成设计,充分利用不同工业废渣在提供碱性物质和膨胀性物质、调整胶结性水化物与膨胀性水化物生成速率协调性等方面的技术优势,利用工业废渣制备的固化剂与普通水泥相比可使固化土强度提高数倍。     

Occurrence and possible sources of polychlorinated biphenyls in surface sediments from the Wuhan reach of the Yangtze River, China

Twenty-seven surface sediment samples were collected from the mainstream and eight tributaries of the Wuhan reach of the Yangtze River, China, in 2005, in order to assess the distribution, possible sources, and potential risk of polychlorinated biphenyls (PCBs) in the environment. The total concentrations of PCBs (the sum of 39 congeners) ranged from 1.2 to 45.1 ng g⁻¹ dry weight, with a mean value of 9.2 ng g⁻¹. Sediment samples with the highest PCB concentrations came from the tributary sites, which are closer to PCB sources. Conversely, PCB concentrations in the sediment from the mainstream sites of Yangtze River were relatively low. The observed PCB levels were higher than those found in the sediments of other rivers in China, but lower than those in river sediments from other urban areas and harbors around the world. Low-chlorinated PCBs, dominated by tetra-PCBs and penta-PCBs, were identified as being prevalent in the surface sediments. Correlation analyses between the PCBs and the geochemistry and heavy metal content of the sediments suggest that the washing of these compounds from the land into the river by floods and heavy rains, or industrial wastewater and domestic sewage, may be the major sources of the PCBs. According to established sediment quality guidelines, the risk of adverse biological effects from the levels of PCBs recorded at most of the studied sites should be insignificant, although the higher concentrations at other sites could cause acute biological damage.     

室内空气污染的防治对策

本文根据室内空气污染物的特性,从污染源控制、法律法规、建筑管理以及其他控制措施等方面,有针对性地提出了各种室内空气污染的防治对策,从而达到改善室内环境空气质量的目的。     

脉冲变频电磁场对水华鱼腥藻生长的效应

对脉冲变频电磁场作用下,扫描频率和磁感应强度的变化对水华鱼腥藻细胞活性和生长的影响进行了研究。结果显示,扫描频率从25~27 Hz增大到1~60 kHz时,磁场对藻细胞活性的抑制作用减小,但增大到60 kHz以上,磁场对藻细胞产生强烈抑制作用,累积水力停留时间4 min的藻样在48 h培养时间内已失去活性停止生长。扫描频率为50~100 Hz和1~60 kHz时,累积水力停留时间2 min的藻样,细胞受到磁场刺激生长加快;只有累积水力停留时间＞6 min,才表现出对藻活性的抑制作用。磁感应强度增大至120 G,磁场对细胞活性产生明显抑制作用,增大磁感应强度有利于对细胞活性和生长的抑制。     

生态补偿与生态云南

构建生态云南的基本要素有：明确的责任；心理准备充分；资金充裕；社会动员、组织动员高效便捷；打环境官司容易；完善的约束——激励机制；履行生态伦理的能力。生态补偿能创造和积累构建生态云南所需要素和条件。本文将云南生态补偿划分为伦理型生态补偿和法制型生态补偿，探讨各类生态补偿的发展策略、步骤、方式和手段。     

Selecting Sites for Converting Farmlands to Wetlands in the Sanjiang Plain, Northeast China, Based on Remote Sensing and GIS

Wetlands in the Sanjiang Plain are rich in biodiversity and natural resources in the northeast of China. However, this wetland area has decreased in size and deteriorated in quality owing to expanded agricultural activities since the 1950s. Converting farmlands to wetlands is necessary to improve these conditions. Using Remote Sensing (RS) and Geographic Information Systems (GIS) technologies, we derived farmland productivity data and hydrology data for the Sanjiang Plain. The farmland productivity data were derived from land use and net primary productivity (NPP) data of the MODIS products. We obtained three productivity farmland classes (low, medium, and high) through the NPP anomaly percentage method. We were only concerned with the low-productivity farmland. Hydrology data were modeled with a wetness index, which was derived from Digital Elevation Model (DEM) data. Based on these two data layers, we identified and prioritized sites for the conversion of farmlands to wetlands. The areas with low farmland productivity and medium or high wetness values have potential to support the conversion of farmlands to wetlands. Potential sites were prioritized in terms of patch size and proximity to natural wetlands and water bodies. We obtained three priority classes, among which the high-priority class would be used as the areas for the recent conversion of farmlands to wetlands. The area of this class was 75,888 ha and accounted for 1.3% of the total farmland area.     

浅议生态环境损害赔偿的理论基础与实施保障

本文立足于环境资源公共物品的属性,探讨构建生态环境损害赔偿制度的理论基础,提出行政主管部门应在生态环境损害赔偿中发挥主导作用。从落实《生态环境损害赔偿制度改革试点方案》的角度出发,从明确责任主体、细化磋商与诉讼程序、健全生态环境损害评估制度、加强资金保障、强化法律与公众监督等方面提出关于改革方案配套制度的八条具体建议。     

Effect of electric intensity on the microbial degradation of petroleum pollutants in soil

Electro-bioremediation is an innovative method to remedy organic-polluted soil. However, the principle of electrokinetic technology enhancing the function of microbes, especially the relationship of electric intensity and biodegradation efficiency, is poorly investigated. Petroleum was employed as a target organic pollutant at a level of 50 g/kg (mass of petroleum/mass of dry soil). A direct current power supply was used for tests with a constant direct current electric voltage (1.0 V/cm). The petroleum concentrations were measured at 3275–3285 nm after extraction using hexane, the group composition of crude oil was analyzed by column chromatography. The water content of soil was kept 25% (m/m). The results indicated the degradation process was divided into two periods: from day 1 to day 40, from day 41 to day 100. The treatment of soil with an appropriate electric field led the bacteria to have a persistent effect in the whole period of 100 days. The highest biodegradation efficiency of 45.5% was obtained after treatment with electric current and bacteria. The electric-bioremediation had a positive effect on alkane degradation. The degradation rate of alkane was 1.6 times higher in the soil exposed to electric current than that treated with bacteria for 100 days. A proper direct current could stimulate the microbial activities and accelerate the biodegradation of petroleum. There was a positive correlation between the electric intensities and the petroleum bioremediation efficiencies with a coefficient of 0.9599.     

低有机碳含量表层土中Fe2O3对γ-666光解的催化作用

考察5种低有机碳含量天然土中Fe₂O₃光催化降解γ-666的光解动力学,γ-666的光解符合准一级动力学方程.从所得的γ-666光解动力学常数可知,随Fe₂O₃质量分数从0.40%增加到5.40%,γ-666的一级光解动力学常数也增大,且两者的线性相关系数为0.952,其在5种天然土中的半衰期随Fe₂O₃含量的增加依次为133.3h,82.5h,44.1h,28.5h,20.4h.由此可见,低有机碳含量天然土中Fe₂O₃对γ-666的光解具有明显的催化作用.