重度富营养化水培条件下烟草的生长特性及其净化效果的研究

研究了烟草在重度富营养化水培条件下的生长特性、根的解剖结构,对其净化效果进行了观测,并对烟草在重度富营养化水中的生长特性变化原因、适应机理进行了探讨。     

沈阳卫工河水中多环芳烃的分布、来源及生态风险初步评价

卫工河水中6月(夏季)16种多环芳烃的含量为0.244～2.038μg·L-1,平均为0.768μg·L-1;9月(秋季)水中总多环芳烃(TPAHs)含量为0.503～0.989μg·L-1,平均0.761μg·L-1;11月(冬季)多环芳烃的含量为0.229～0.427μg·L-1,平均含量为0.346μg·L-1。个别地点苯并(a)芘含量明显高于国家地表水环境质量标准(GB3838-2002);对卫工河水中多环芳烃污染来源分析发现,多环芳烃的主要来源燃烧来源;通过商值法对卫工河的初步风险评价表明,卫工河水中苯并(a)芘存在较大的生态风险,应引起有关部门的进一步关注。     

厌氧型生物反应器产CH4期水解动力学模型研究

为研究渗滤液回灌和温度对填埋垃圾产CH4的影响,在不同温度下,通过对3个已进入产CH4期的厌氧型生物反应器实施不同的回灌操作,并根据p(CODCr)和产CH4速率的监测数据,建立了厌氧型生物反应器固相垃圾的水解模型.产CH4速率的模型计算的模拟值与D1,D2和D3柱实测值的相关系数分别为0.895 5,0.809 1和0.915 6,具有较高的可靠性.其中保持较高的产CH4速率且恒定温度的D2柱的固相垃圾水解系数是D1柱的12倍左右;同时随着回灌频率的降低,D3柱水解速率系数从0.007 6降到0.002 7,与D1柱的相对差也逐渐增大,保持较高的温度(35℃左右)和较高回灌频率有利于固相垃圾的水解和厌氧型生物反应器的快速稳定.     

两相厌氧工艺的研究现状及其应用

两相厌氧工艺因产酸相和产甲烷相的分离而具有一系列的特点和优势。在此对两相厌氧系统进行了分析,阐述了它的理论依据和运行机理．着重剖析了两相厌氧工艺的影响因素、工艺特点和适用范围,并对其发展和实际应用现状进行了论述。表明此工艺的先进性和适用性。     

青海湖流域农田生态系统氢氧同位素特征及其水分利用变化研究

水分条件是直接影响农作物产量高低的主要限制因子之一,但对青海湖流域油菜和燕麦植物水分利用方式的认识尚不清楚。论文收集油菜和燕麦整个生育期内降水、植物和土壤水氢氧稳定同位素组成,并通过直接对比法和多源混合模型定量地计算出油菜和燕麦对不同深度土壤水分利用比例。结果表明：降水中同位素组成表征出较大的波动性变化,浅层土壤水同位素组成受蒸发作用影响明显富集于深层土壤水分,且土壤水中同位素在垂直方向上呈浅层土壤水较富集于深层土壤水。油菜在生育期内根系吸水方式在浅层和深层土壤间发生明显的转换,如在蕾薹期、开花期、灌浆期及成熟期主要依赖于0~10 cm（95.1%）、0~10 cm（68%和44.8%）、30~60 cm（69.9%）及0~10 cm（38.8%）的土壤水分。而燕麦根系吸水范围却没有表征出明显的改变,在整个生育期内土壤水分利用深度在0~30 cm间变化。这将为高寒地区耕作方式调整及发展节水高效的现代农业提供理论依据。     

水体中胺鲜酯残留量的测定及其光解特性

建立了利用固相萃取-气相色谱(SPE-GC)测定水体中胺鲜酯残留量的方法.考查了3种不同固相萃取柱(C18、florisil、OasisR HLB)对水溶性农药胺鲜酯的吸附效果,发现它们对水中胺鲜酯的萃取效率依次为8%、13% 和96%;进一步研究了利用OasisR HLB萃取水中胺鲜酯的最佳条件(洗脱剂二氯甲烷用量4～8 mL),OasisR HLB(60 mg)小柱对胺鲜酯的保留容量高达200 μg·柱-1.运用该方法测定胺鲜酯光解试验样品,结果表明胺鲜酯质量浓度的对数与光照时间呈良好的线性关系.胺鲜酯在氙灯下的光化学降解符合一级动力学反应,光解半衰期为82 min,较易光解.     

Multispectral image analysis method to determine dynamic fluid saturation distribution in two-dimensional three-fluid phase flow laboratory experiments

The need for measuring dynamic fluid saturation distribution in multi-dimensional three-fluid phase flow experiments is hampered by lack of appropriate techniques to monitor full field transient flow phenomena. There is no conventional technique able to measure dynamic three-fluid phase saturation at several array points of the flow field at the same time. A multispectral image analysis technique was developed to determine dynamic NAPL, water and air saturation distribution in two-dimensional three-fluid phase laboratory experiments. Using a digital near-infrared camera, images of sand samples with various degrees of NAPL, water and air saturation were taken, under constant lighting conditions and within three narrow spectral bands of the visible and near-infrared spectrum. It was shown that the optical density defined for the reflected luminous intensity was a linear function of the NAPL and the water saturation for each spectral band and for any two and three-fluid phase systems. This allowed the definition of dimensionless lump reflection coefficients for the NAPL and the water phase within each spectral band. Consequently, at any given time, two images taken within two different spectral bands provided two linear equations which could be solved for the water and the NAPL saturation. The method was applied to two-dimensional three-phase flow experiments, which were conducted to investigate the migration and the distribution of LNAPL in the vadose zone. The method was used to obtain continuous, quantitative and dynamic full field mapping of the NAPL saturation as well as the variation of the water and the air saturation during NAPL flow. The method provides a non-destructive and non-intrusive tool for studying multiphase flow for which rapid changes in fluid saturation in the entire flow domain is difficult to measure using conventional techniques.     

金沙江一期工程蓄水前后绥江段鱼类群落多样性特征

为探索流域梯级水电开发对鱼类群落多样性影响,于2011年(蓄水前)和2015年(蓄水后)对金沙江下游绥江断面进行渔业资源调查,分析鱼类群落结构特征。结果表明,绥江段共计采集鱼类60种,隶属于5目12科,其中长江上游特有鱼类12种。蓄水前以瓦氏黄颡鱼(Pelteobagrus vachelli)、圆口铜鱼(Coreius guichenoti)、光泽黄颡鱼(Pelteobagrus nitidus)为优势种类;蓄水后以草鱼(Ctenopharyngodon idellus)、鳙(Aristichthys nobilis)、鲢(Hypophthalmichthys molitrix)为优势种类。与蓄水前相比,鱼类群落Margalef丰富度指数、Shannon-Weiner多样性指数、Pielou均匀度指数均呈现下降趋势,但无显著性差异(P0.05)。根据生态类群分析,静水缓流型鱼类由蓄水前54%增加到蓄水后的71%,河道洄游型鱼类从39%减少到20%,江湖洄游型鱼类蓄水前后变化不大。丰度生物量比较曲线显示,蓄水前绥江段鱼类群落未受到干扰,而蓄水后受到严重干扰。库区蓄水后总生物量有明显增加趋势,但优势种类趋于小型化、种类结构单一化。为科学保护金沙江下游流域鱼类生物多样性,建议成立鱼类保护区、开展梯级生态调度和加强流域环保预警研究等措施。     

燃煤电厂排放总气态汞连续自动监测技术的选择

介绍了汞连续排放监测系统和汞吸附管采样系统的主要特点,比较了不同仪器的测定原理、样品处理技术、检出限和测定汞的形态,报道了美国环境保护署认证中心关于两个系统的认证结果.建议将汞连续排放监测系统与汞吸附管监测系统两种技术联合用于我国燃煤电厂排放总气态汞的自动监测.     

Effects of Spatial Distribution of Prairie Vegetation in an Agricultural Landscape on Curve Number Values

The curve number (CN) method is used to calculate runoff in many hydrologic models, including the Soil and Water Assessment Tool (SWAT). The CN method does not account for the spatial distribution of land cover types, an important factor controlling runoff patterns. The objective of this study was to empirically derive CN values that reflect the strategic placement of native prairie vegetation (NPV) within row crop agricultural landscapes. CNs were derived using precipitation and runoff data from a seven‐year period for 14 small watersheds in Iowa. The watersheds were planted with varying amounts of NPV located in different watershed positions. The least squares and asymptotic least squares methods (LSM) were used to derive CNs using an initial abstraction coefficient (λ) of 0.2 and 0.05. The CNs were verified using leave‐one‐out cross‐validation and adjustment for antecedent moisture conditions (AMC) was tested. The asymptotic method produced CN values for watersheds with NPV treatment that were 8.9 and 14.7% lower than watersheds with 100% row crop at λ = 0.2 and λ = 0.05, respectively. The derived CNs produced Nash‐Sutcliffe efficiency values ranging from 0.4 to 0.7 during validation. Our analyses show the CNs verified best for the asymptotic LSM, when using λ of 0.05 and adjusting for AMC. Further, comparison of derived CNs against an area weighted CN indicated that the placement of vegetation does impact the CN value. Editor's note : This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series.