渗滤液中污染物的粒度分布及其应用

渗滤液是一种难于处理的废水.论述了渗滤液中污染物的粒度分布.指出了不同粒度污染物中胶体态组分富含难降解有机物和重金属,其性质稳定,含量较高,对渗滤液的处理工艺选择和去除效果影响重大.最后对渗滤液的资源化进行了初步探讨.     

燃煤飞灰制备脱硫剂的试验研究

以飞灰和石灰为原料,经消化制得不同消化时间、消化温度和原料配比的脱硫剂,对实验样品进行比表面积、孔径分布等表面特性测定,并在固定床上进行脱硫试验研究。研究表明,合理的孔径分布利于脱硫反应,实验制得最佳脱硫剂的比表面积是54.953m2/g。     

Socioeconomic Factors Affecting Farmers’ Perceptions of Land Degradation and Stonewall Terraces in Central Palestine

Land degradation by soil erosion is a socioeconomic and environmental problem facing many developing countries. Application of stonewall terraces for soil moisture conservation is vital to reducing the environmental impacts of this phenomenon. To this end, a field plot experiment was conducted in the study area along with the use of a closed-ended questionnaire. The object of the experiment was to study the socioeconomic impacts of soil erosion on local farmers and their adoption of the stonewall terrace technique. The study showed a higher net profit in areas that had implemented terrace conservation practices than in areas that had not (i.e., 3.5 to 6 times higher net profit). Correlation analysis indicated that the farmers’ perceptions, land ownership, and geomorphology were significantly related to the farmers’ incentives and willingness to adopt terraces as soil conservation measures (P < 0.05), although the correlations were negative. Smallholder farmers (52% of the interviewed farmers) were involved in the sale of the agricultural land for urban uses, largely because of the high price and immediate returns offered. However, the associated land use changes warrant greater involvement of both the private and public sectors. This cooperation may be accomplished through the introduction of a long-term agricultural loan system and the development of proper legislation accompanied by a comprehensive and durable infrastructure and service system with the goal of reducing the negative impact of land use changes and encouraging sustainable use of resources.     

空气负离子暴露对秀丽隐杆线虫(Caenorhabditis elegans)的生物学效应

利用模式生物秀丽隐杆线虫(Caenorhabditis elegans)研究了电晕法空气负离子(Electrically generated negative air ions,ENIs)暴露的生物学效应.将成年野生型和mev-1突变型线虫及新鲜虫卵持续暴露于空气负离子中(空气负离子剂量1×105～1.5×105ions·cm-3),观察空气负离子暴露对线虫发育周期、寿命、繁殖性能和性腺细胞凋亡的影响.结果表明:空气负离子暴露可显著加速野生型和mev-1突变型线虫发育(p<0.05),缩短寿命(p<0.05),与野生型相比,空气负离子暴露对mev-1突变线虫寿命影响更大(p<0.05);空气负离子暴露可显著降低线虫后代数量(p<0.05),原因可能在于空气负离子暴露显著诱导性腺细胞凋亡的增加(p<0.05).以上结果表明,持续空气负离子暴露对线虫具有损伤作用,mev-1基因突变导致线虫对空气负离子暴露更加敏感.     

Particulate Matter Over A Seven Year Period in Urban and Rural Areas Within, Proximal and Far from Mining and Power Station Operations in Greece

Lignite mining operations and lignite-fired power stations result in major particulate pollution (fly ash and fugitive dust) problems in the areas surrounding these activities. The problem is more complicated, especially, for urban areas located not far from these activities, due to additional contribution from the urban pollution sources. Knowledge of the distribution of airborne particulate matter into size fraction has become an increasing area of focus when examining the effects of particulate pollution. On the other hand, airborne particle concentration measurements are useful in order to assess the air pollution levels based on national and international air quality standards. These measurements are also necessary for developing air pollutants control strategies or for evaluating the effectiveness of these strategies, especially, for long periods. In this study an attempt is made in order to investigate the particle size distribution of fly ash and fugitive dust in a heavy industrialized (mining and power stations operations) area with complex terrain in the northwestern part of Greece. Parallel total suspended particulates (TSP) and particulate matter with an aerodynamic diameter less than 10 μm (PM10) concentrations are analyzed. These measurements gathered from thirteen monitoring stations located in the greater area of interest. Spatial, temporal variation and trend are analyzed over the last seven years. Furthermore, the geographical variation of PM10 – TSP correlation and PM10/TSP ratio are investigated and compared to those in the literature. The analysis has indicated that a complex system of sources and meteorological conditions modulate the particulate pollution of the examined area.     

Lake ecosystem responses to rapid climate change

In this paper, we examine the consequences of rapid climate change on lake ecosystems in terms of two main effects: variability effects and magnitude effects. How these factors influence life history selection is considered by focusing upon body size as a quantifiable and strong correlate of life history variation (Pianka 1970, McNab 1980, Charnov 1991). We then consider the relationship between the concept of biological diversity and the diversity of life history strategies in the context of rapid climate change.     

速生杨木粉尘最小点火能的实验研究

为防止木材加工中木质粉尘燃爆事故的发生,以纤维板生产中常见的原材料速生杨木粉尘作为研究对象,在分析粉尘粒径分布、元素分析、工业分析及形貌特征的基础上,采用1.2 L哈特曼管对3种不同粒径（0~50,＞50~96,＞96~180 μm）速生杨木粉尘进行最小点火能实验,探究点火延迟时间、喷粉压力、质量浓度和粒径分布对速生杨木粉尘最小点火能的影响及变化规律。研究结果表明:在质量浓度为500 g/m3时,分别增加点火延迟时间和喷粉压力,最小点火能都先减小后增大;最佳点火延迟时间和最佳喷粉压力分别为120 ms和120 kPa;粒径对最佳点火延迟时间和最佳喷粉压力无显著影响。在点火延迟和喷粉压力分别为120 ms和120 kPa条件下,最小点火能随质量浓度的增加先减小后增大。粉尘粒径与最小点火能呈正相关性,3种样品的最小点火能分别为1~3,1~3和7~13 mJ,对应的敏感质量浓度分别为500 ,750和1 250 g/m3,属于特别着火敏感性粉尘。     

水系沉积物重金属分析前处理方法

建立了水系沉积物中6种重金属分析的前处理方法,研究了样品粒径、消解前处理对测定结果的影响,对方法适用性作出评价,并对实际样品进行测定。结果表明:通过Hg元素含量的测定,粒径为0.147 mm的沉积物粒径可满足分析要求;采用微波-硝酸-盐酸-氢氟酸消解、ICP-MS法,对5种不同类型沉积物标准样品的6种重金属的测定结果显示,该方法精密度好、准确度高。利用建立的方法测定广西某河流湖库沉积物样品,6种元素测定结果 RSD为1.57%~11.1%,加标回收率大于74.4%。     

Distribution,source, and ecological risk assessment of PAHs among size and density fractions in contaminated sediments from the Yellow River of Henan section

This study investigated particle size and density distributions of polycyclic aromatic hydrocarbons (PAHs) in two surface sediments (JZ and KF), collected from the Yellow River of Henan section, China. The concentrations of Σ₁₅PAHs ranged from 35.6 to 45862?ng g^?1 dry wt, which were greatly elevated in coarse particles and low-density fractions. The Σ₁₅PAHs concentrations in low-density fractions were 533 (JZ) and 996 (KF) times higher than those in the corresponding high-density fractions. However, due to relatively less quantities of low-density fractions (0.27–2.33%), most of the PAHs were contributed by the high-density components. For both sediments, the influence factors of PAHs source in the environment were very complex, more so than the level of TOC and BC content. JZ sediment was dominated by 4-ring to 6-ring PAHs (61.5–75.1%), while, 2-ring to 3-ring PAHs were abundant in KF samples (39.8–72.6%). Ratios of specific PAHs reflected PAHs among the size- and density-fraction of each sediment may be contaminated by mixed of pyrolytic and petrogenic origin. Additionally, ecological risk assessment of PAHs suggested that total toxic equivalent values of PAHs in the low-density fractions were much higher than those of the corresponding high-density fractions in the studied area.     

单丝滤布优选及悬浮物特性对其过滤性能的影响

根据国标测定单丝滤布的孔径、过水通量及透水阻力,从而优选出过滤性能最优的滤布。探究了悬浮物粒径、浓度及比表面积对单丝滤布过水通量的影响,并采用HERMIA模型分析了单丝滤布的堵塞机理。实验结果表明:悬浮物粒径越大单丝滤布过水通量的下降越明显,过滤后悬浮物中位粒径与滤布孔径的比值均在0.36～0.46;悬浮物的浓度越高、比表面积越小,在滤布表面的架桥作用越强,形成的滤饼层孔隙越小,滤布越容易被污染。