西北干旱区柴窝堡湖干涸湖底粉尘潜在扩散特征

运用HYSPLIT模型,结合美国环境预报中心(NCEP)和大气研究中心(NCAR)2000~2013年的再分析气象资料,对柴窝堡盆地粉尘潜在扩散的时间和空间特征进行了研究.结果表明:柴窝堡湖干涸湖底粉尘潜在扩散范围具有明显的季节分异.春季粉尘潜在扩散范围和密度最大,覆盖我国大部分地区,最远可达朝鲜半岛部分地区,其次是秋季,夏季粉尘潜在扩散以1000m为界表明出明显的高度差异,冬季粉尘潜在扩散范围和密度均是最小的.随高度增加,不同季节气流可能携带粉尘密度均呈降低趋势.受地形影响,粉尘潜在扩散有两个主要通道,100m以下主要向西南方向扩散,而100m以上主要向东南方向扩散.柴窝堡盆地干涸湖底大量的粉尘在气流携带下可以长时间远距离输送,在近源区沉降,严重影响乌鲁木齐及其周边地区,并可能加速天山山区的雪冰消融.     

LDPE膜被动采样技术预测模型的建立及其应用

选用3种厚度的低密度聚乙烯(LDPE)膜(76,56和25μm)作为研究对象,对辛醇-水分配系数的对数(logKow)>2的有机污染物采用被动采样技术进行膜-水分配系数(Kpew)实测实验和动力学实验,首次建立考虑时间(t),膜厚度(d)和动力学3个因素的LDPE膜 Kpew预测模型.实验结果表明,预测模型得到的Kpew与实测Kpew的相对误差为±0.03,证明了预测模型的准确性和可靠性.Kpew预测模型的建立避免了实验监测Kpew的繁琐实验过程,从而极大地提高了有机污染物的监测效率.将预测模型Kpew值应用于浑河与东洲河有机污染物质的监测,监测结果进一步表明了预测模型的准确性和实用性.此外本文首次提出了苯系物的Kpew值,对LDPE膜被动采样技术应用的延伸属于突破性进展.     

悬浮液直接进样塞曼石墨炉平台原子吸收法测定土壤中痕量铅

研究了悬浮液直接进样 ,石墨炉平台原子吸收法测定土壤中痕量铅 ,方法简便快速 ,检出限 (3σ)为 4.4× 1 0 - 1 2 g,相对标准偏差 (n=6)小于 3 .0 % ,回收率在 91 %～ 1 0 7%之间     

粉煤灰基吸附剂对模拟废水中Cd2+的吸附性能

以粉煤灰为原料、Na2CO3为助熔剂,采用盐熔融—水浴结晶法制备粉煤灰基吸附剂。探讨了吸附剂的最佳制备条件及其对模拟废水中Cd2+的最佳吸附条件、吸附动力学和吸附机理。实验结果表明:制备吸附剂的最佳工艺条件为m(粉煤灰)∶m(Na2CO3)为1∶2,焙烧温度为450℃;采用最佳制备工艺条件下制备的吸附剂(记作2-450℃-FA吸附剂),在初始Cd2+质量浓度为300 mg/L、初始溶液pH为7.7、振荡时间为120 min的条件下,对模拟废水中Cd2+的去除率为98.0%。2-450℃-FA吸附剂对Cd2+的吸附主要受颗粒内扩散控制,吸附过程可用准二级吸附动力学方程很好地描述。Ea为77.22 kJ/mol,吸附过程主要为化学吸附。     

Trisomy 16 detected at chorion villus sampling

Trisomy 16 detected at chorion villus sampling (CVS) may reflect the placental but not the fetal karyotype. We describe a case in which the pregnancy continued until intrauterine death at 37 weeks. Cytogenetic study of two placental samples showed 47, +16 and 46,XX; the fetus was morphologically grossly normal, but fetal tissue culture was unsuccessful. Conservative management may be appropriate when trisomy 16 is detected at CVS and the pregnancy is normal ultransonographically.     

Simultaneous sampling of PCDD/PCDF inside the combustion chamber and on four boiler levels of a waste incineration plant

At a MSWI (municipal solid waste incinerator) plant PCDD/PCDF samples (gasphase and particulates) were taken simultaneously be a shock-freezing method in the incinerator combustion chamber at approx. 800°C and in four sampling sections in the boiler at about 490°C, 370°C, 330°C and 270°C. In this way PCDD/PCDF-formation in the flow through the boiler was determined. Two data sets were evaluated. A considerable PCDD/PCDF-formation had occurred already at boiler temperatures of about 490°C; the highest concentration, however, was found at the end of the boiler at about 300°C. The accompanying measuring program of plant parameters made the calculation of the PCDD/PCDF mass flows possible, which allowed the inclusion of the PCDD/PCDF-content in the ESP dust in the mass flow calculations.     

Assessing the Restoration Success of River Widenings: A Landscape Approach

During the last 200 years, many rivers in industrialized countries have been modified by canalization. In the last two decades, the philosophy of river management has changed considerably, and restoration of ecological integrity has become an important management goal. One appealing restoration approach is to create “river widenings” that permit braiding within a limited area. This study presents a new and efficient framework for rapidly assessing such widening projects and offers a novel method to comparing restored sites with near-natural stretches (stencil technique). The proposed framework evaluates spatial patterns of riparian habitat types using landscape metrics as indicators. Three case studies from river restoration (river widening) in Switzerland are presented for demonstration purposes.The method compares restored sites with prerestoration conditions and near-natural conditions, which are assumed to represent the worst and best case states of a river system. To take into account the limited spatial extent of the restored sites, the so-called “stencil technique” was developed, where the landscape metrics of the near-natural reference sites are calculated for both the entire study area and smaller sections (clips). The clips are created by using a stencil that has the exact shape and size of the restored area (random window-sampling technique). Subsequently, the calculated metrics for the restored sites are compared to the range of values calculated for the near-natural data subset. Our studies show that the proposed method is easy to apply andprovides a valid way to assess the restoration success of river widenings. We found that river widenings offer real opportunities for establishing riparian habitats. However, they promote mainly pioneer successional stages and the habitat mosaic of the restored section is more complex than at the near-natural reference sites.     

Developing an optimal sampling design. A case study in a coastal marine ecosystem

The development of a sampling design for optimisingsampling site locations collected from a coastalmarine environment has been the purpose of the presentwork; application of statistical analysis and spatialautocorrelation methods have been carried out. Thedataset included data collected from 34 sampling sitesspaced out in the Strait of Lesbos, Greece, arrangedin a 1×1 NM grid. The coastal shallow ecosystem wassubdivided into three zones, an inner one (7stations), a middle one (16 stations) and an offshorezone (11 stations). The standard error of thechlorophyll-a concentrations in each zone hasbeen used as the criterion for the sampling designoptimisation, resulting into reallocation of thesampling sites into the three zones. The positions ofthe reallocated stations have been assessed byestimation of the spatial heterogeneity and anisotropyof chlorophyll-a concentrations usingvariograms. Study of the variance of the initialdataset of the inner zone taking into account spatialheterogeneity, revealed two different sub-areas andtherefore, the number of the inner stations has beenreassessed. The proposed methodology eliminates thenumber of sampling sites and maximises the informationof spatial data from marine ecosystems. It isdescribed as a step-by-step procedure and could bewidely applied in sampling design concerning coastalpollution problems.     

连续采样和间断采样监测大气中SO2平均浓度的研究

本文通过对连续采样和间断采样监测大气ＳＯ２浓度的对比实验数据进行分析，认为２４ｈ逐时间断采样的ＳＯ２浓度平均值和连续采样的ＳＯ２日平均浓度之间没有偏差，而几个时刻间断采样的平均值与连续值采样的日平均浓度存在显著性差异。