Heavy metals in albanian coastal sediments

Heavy metals (Fe, Mn, Cr, Ni, Cu, Cd, Pb, Sn) concentration has been determined on 39 coastal sediment samples collected in Albania. The relationship between the heavy metals content and the grain size has been considered. All metals, except Cu and Cd, resulted accumulated in the finest fraction, which constituted up to 95% of most of the considered sediments. A good correlation has been found for Ni, Cr, Fe, Zn, Cu in the entire area, indicating a common origin for these metals in the analyzed sediments. Concentration values fall in the range reported for Dinaric chain derived sediments, revealing, generally, a natural origin of the metal contents. Though in some selected areas such as the Drin and the Skumbin Bay, an antropogenic input of Cr, Fe, Ni and Cu can be observed, as the result of discharging of mines and smelter activities.     

Dependency of polycyclic aromatic hydrocarbon concentrations on particle size distribution in Tehran atmosphere

In this work, the airborne particulate matter with an aerodynamic diameter less than 10 µm (PM₁₀) was fractionated in a six-stage high-volume cascade impactor to identify particulate size distribution in Tehran atmosphere. The study was conducted at 15 sites located in the north, south, east, west, and central parts of Tehran in 2005. Air samples were analyzed for 16 polycyclic aromatic hydrocarbons (PAHs) by HPLC. The daily PM₁₀ concentrations at the peak of traffic in roadside areas were found to be 106–560 µg m^?3. The cumulated concentration sum of PAHs, based on 16 species, was found to have an average concentration of 380 ng m^?3. Furthermore, it was found that more than 60% of PAHs belonged to the small particulate size range, having sizes of less than 0.49 µm, some containing benzo(ghi)perylene and indeno(123cd)pyrene (high molecular weight) with average concentrations of 8 and 6 ng m^?3 and fluorene, phenanthrene, and fluoranthene (low molecular weight) with average concentrations of 14, 13, and 19 ng m^?3, respectively. In addition, the results revealed that the lighter three- and four-ring PAH compounds were the most abundant pollutants in the air collected at all the sampling sites.     

不同粒径和不同浓度清洁疏浚物对2种海洋微藻生长的影响

采用室内模拟试验研究了不同粒径和不同浓度悬浮清洁疏浚物对2种常见海洋微藻小球藻（Chlorella sp.）和新月菱形藻（Nitzschia closterium）生长的影响.结果表明,在8d的试验周期里,与对照组相比,不同浓度清洁疏浚物对2种海洋微藻生长的影响均达极显著水平（P＜0.01）.在相同粒径范围内,悬浮清洁疏浚物质量浓度为1～7g·L-1时,其对微藻生长的抑制作用随浓度升高而增加.随悬浮清洁疏浚物粒径的减小,2种海洋微藻的细胞密度呈下降趋势,＞88～ 125 μm粒径范围内生长的藻细胞受影响最小,0～16 μm粒径范围内生长的藻细胞受影响最大.悬浮清洁疏浚物对2种海洋微藻比生长速率的抑制作用明显,延缓了最大比生长速率出现的时间.2种海洋微藻对悬浮清洁疏浚物的敏感性存在差异,小球藻对悬浮清洁疏浚物的反应更加迅速.     

Effects of Growth Form and Functional Traits on Response of Woody Plants to Clearing and Fragmentation of Subtropical Rainforest

The conservation implications of large‐scale rainforest clearing and fragmentation on the persistence of functional and taxonomic diversity remain poorly understood. If traits represent adaptive strategies of plant species to particular circumstances, the expectation is that the effect of forest clearing and fragmentation will be affected by species functional traits, particularly those related to dispersal. We used species occurrence data for woody plants in 46 rainforest patches across 75,000 ha largely cleared of forest by the early 1900s to determine the combined effects of area reduction, fragmentation, and patch size on the taxonomic structure and functional diversity of subtropical rainforest. We compiled species trait values for leaf area, seed dry mass, wood density, and maximum height and calculated species niche breadths. Taxonomic structure, trait values (means, ranges), and the functional diversity of assemblages of climbing and free‐standing plants in remnant patches were quantified. Larger rainforest patches had higher species richness. Species in smaller patches were taxonomically less related than species in larger patches. Free‐standing plants had a high percentage of frugivore dispersed seeds; climbers had a high proportion of small wind‐dispersed seeds. Connections between the patchy spatial distribution of free‐standing species, larger seed sizes, and dispersal syndrome were weak. Assemblages of free‐standing plants in patches showed more taxonomic and spatial structuring than climbing plants. Smaller isolated patches retained relatively high functional diversity and similar taxonomic structure to larger tracts of forest despite lower species richness. The response of woody plants to clearing and fragmentation of subtropical rainforest differed between climbers and slow‐growing mature‐phase forest trees but not between climbers and pioneer trees. Quantifying taxonomic structure and functional diversity provides an improved basis for conservation planning and management by elucidating the effects of forest‐area reduction and fragmentation. Efectos de la Forma de Crecimiento y Atributos Funcionales en la Respuesta de Plantas Leñosas al Desmonte y Fragmentación de Bosque Lluvioso Subtropical     

Response of Neotropical Bat Assemblages to Human Land Use

Neotropical bats are sensitive to human‐induced habitat changes, and some authors believe bats can be used as bioindicators. In the literature, however, the results are disparate. Some results show bat diversity deceases as disturbance increases, whereas others indicate no effect. Determining the general response patterns of bats when they encounter different degrees of human‐induced disturbance across the Neotropics would help to determine their usefulness as bioindicators. In a series of meta‐analyses, we compared the occurrence frequency of bat species between well‐preserved forests and human‐use areas. We obtained data through an extensive review of published peer‐reviewed articles, theses, and reports. The overall effect size indicated that human‐use areas harbored more bat species than well‐preserved forests. Different response patterns emerged when meta‐analyses were conducted separately by family, feeding habit, vegetation stratum, and conservation status. Our results suggest that bat assemblages display strong responses to forest loss and land‐use change and that the direction and magnitude of these responses depends on the bat group under study and the type of disturbance. Our results are consistent with the idea that bats are useful for assessing the effects of habitat changes in the Neotropics. However, with our meta‐analyses we could not detect fine differences in bat feeding habits, especially within Phyllostomidae, or elucidate the effect of landscape configuration. Respuesta de Ensambles de Murciélagos Neotropicales al Uso de Suelo por Humanos     

农村室内薪柴燃烧的颗粒物和炭黑排放因子

室内薪柴燃烧是大气污染的重要来源,其排放的污染物对气候变化和人体健康都有很大影响。对该来源排放量的可靠估算是进行排放效应分析和合理控制的重要前提,而估算的可靠性主要取决于燃料消耗量和排放因子的准确性。目前,我国针对农村柴灶薪柴燃烧颗粒物排放因子的测定数据很少,变异很大,不足以支持可靠的排放清单估算。测定了9种薪柴(枫桦、兰考泡桐、黑杨、大叶风杨、楝树、枣树、柿树、桑树和桃树)在中国北方典型农村炉灶中燃烧产生的颗粒物(PM)、有机碳(OC)和元素碳(EC)的排放因子。受燃料种类、性质和燃烧条件的影响,测得的排放因子差别较大。9种薪柴各自的PM、EC和OC的排放因子变化范围分别为(0.74±0.13)～(6.23±1.47)g.kg-1,(0.10±0.06)～(0.97±0.28)g.kg-1和(0.14±0.03)～(3.81±0.92)g.kg-1(以干质量计)。全部薪柴的PM、EC和OC的排放因子均值和标准差分别为(2.58±2.15)、(0.29±0.31)和(0.98±1.24)g.kg-1。室内薪柴燃烧PM、EC和OC排放因子之间呈显著的相关性关系。各种薪柴燃烧排放的颗粒物粒径分布相似,均以细颗粒物为主,PM2.1占PM10总质量的90%以上。此外,除EC排放因子外,薪柴燃烧的PM和OC排放因子与校正燃烧效率显著负相关(P<0.05)。细颗粒物组分PM2.1与校正燃烧效率显著负相关(P<0.05),与燃料含水量显著正相关(P<0.05)。     

保定大气颗粒物中水溶性无机离子质量浓度及粒径分布

为研究保定市大气颗粒物中水溶性无机离子的质量浓度水平、季节变化和粒径分布特征,于2010年8月—2011年8月利用Andersen分级采样器采集大气颗粒物样品,并用离子色谱分析其中的离子组成. 结果表明,细粒子(PM_2.1)中主要水溶性无机离子为SO₄2-、NO₃-和NH₄+,三者质量浓度平均值分别为23.18、21.99和11.44μg/m3;粗粒子(PM>2.1)中主要水溶性无机离子为NO₃-、Ca2+和SO₄2-,三者质量浓度平均值分别为10.60、10.39和10.14μg/m3. 细粒子中ρ(SO₄2-)、ρ(NO₃-)、ρ(NH₄+)、ρ(Cl-)和ρ(K+)的季节性变化相似,均为冬季>秋季>夏季>春季;粗粒子中ρ(NH₄+)、ρ(K+)和ρ(NO₃-)呈现出与细粒子不同的季节性变化趋势,ρ(NH₄+)和ρ(K+)均为冬季>夏季>秋季>春季,而ρ(NO₃-)则为夏季>秋季>冬季>春季. 粗、细粒子中ρ(Ca2+)和 ρ(Mg2+)的季节性变化特征相似,均为冬季最高、夏季最低. ρ(SO₄2-)、ρ(NO₃-)、ρ(Na+)和ρ(K+)均呈双峰分布,分别在＞0.43~1.1μm和＞4.7~5.8μm出现峰值; ρ(NH₄+)和ρ(Cl-)呈细模态单峰分布,在＞0.43~1.1μm出现峰值; ρ(Mg2+)和 ρ(Ca2+)呈粗模态单峰分布,在＞4.7~5.8μm出现峰值. 二次源和生物质燃烧是细粒子的主要来源,扬尘对粗粒子影响较大.      

Do environmental regulations disproportionately affect small businesses? Evidence from the Pollution Abatement Costs and Expenditures survey

This paper examines whether the impact of environmental regulations differs by the size of the business. We consider the net effect of statutory, enforcement, and compliance asymmetries by estimating the relationship between plant size and pollution abatement expenditures, using establishment-level data on U.S. manufacturers from the Census Bureau's Pollution Abatement Costs and Expenditures (PACE) survey and from its Annual Survey of Manufactures and Census of Manufactures. We model establishments' pollution abatement operating costs (PAOC) per unit of economic activity as a function of establishment size, industry, state, and year. Our results show that PAOC intensity increases with establishment and firm size.     

铁路隧道火灾拱顶附近最高温度预测模型研究

隧道拱顶下方最高温度是结构防火设计中的一个重要参数,对不同火灾工况下隧道拱顶附近最高温度的变化规律进行数值模拟研究。对比分析网格尺寸对火灾模拟结果的影响,结果显示当网格尺寸为0.1D*时模拟结果比较准确。分析了不同纵向通风风速、不同火源热释放速率及不同火源面到拱顶距离的情况下Kurioka最高温度模型的有效性,得出Kurioka最高温度模型在通风风速较小或不通风情况下是失效的。最后,对模型进行修正,给出一个具有广泛应用的隧道拱顶附近最高温度预测模型。     

窄脉冲电晕放电烟气脱硫产物粒径分析的实验研究

为了便于脱硫产物的收集和应用,用沉降法采样,用电子显微镜对产物气溶胶进行粒径分析．实验在窄脉冲电晕放电装置上,模拟含硫烟气在工况条件下（气体流量２ｍ３／ｈ,反应器入口处ＳＯ２浓度２０００ｍｌ／ｍ３,ＳＯ２和ＮＨ３在通道中停留时间为５ｓ以上,温度６０℃、水蒸气体积比７．５％,相对湿度３８．２％）进行．电子显微镜的观测结果显示,脱硫产物粉尘结构疏松,颗粒形状不规则．根据电镜照片的统计结果,得出产物粉尘的数目中位径ＮＭＤ为０．４０μｍ,几何标准偏差σ１＝５．２１;质量中位径ＭＭＤ为２．８２μｍ,几何标准偏差σ２＝１．４３