Impact of Vegetative Cover on Runoff and Soil Erosion at Hillslope Scale in Lanjaron, Spain

Soil loss and surface runoff patterns over a four-year period (1997–2000) were studied in erosion plots from three hillslopes under different vegetative covers (Rosmarinus officinalis, Triticum aestivum and natural-spontaneous vegetation) in Lanjaron (Alpujarras) on the south flank of the Sierra Nevada of southeast Spain. The erosion plots were located on the hillslopes at 35.5% incline, at 1,480 m in altitude and with 41.8 m² (21 m×1.9 m) in area. The vegetative covers were tested for effectiveness in controlling the surface runoff and soil loss production. The highest runoff and erosion values, ranging from 114.1 to 1.7 mmyr^–1 and from 14,564.3 to 6.6 kgha^–1yr^–1, respectively, over the entire study period, were measured under the Triticum aestivum. In the Rosmarinus officinalis, runoff ranged from 7.9 to 1.3 mmyr^–1 and erosion from 156.4 to 2.3 kgha^–1yr^–1, while on the hillslope under natural-spontaneous vegetation, runoff ranged from 4.4 to 0.9 mmyr^–1 and erosion from 322.3 to 2.2 kgha^–1yr^–1. According to the results the vegetative covers of Rosmarinus officinalis and natural-spontaneous vegetation reduced the soil losses by 99 and 98%, with respect to the Triticum aestivum, and the runoff losses by 94 and 96%, respectively. Also, the Rosmarinus officinalis and natural-spontaneous plants influenced infiltration by intercepting much of the rainfall water respect to the Triticum aestivum. Monitoring allowed more direct linkages to be made between management practices and their impacts on runoff and soil erosion, thereby enabling to identify problems and take appropriate preventive measures to improve the management practices.     

微通道内细颗粒驻波会聚/分离过程的数值模拟

为了研究微通道内可吸入颗粒的声波会聚现象,在两相流的框架下,对三出口微通道颗粒分离元件实现了声-流场中的颗粒运动的两相流动计算;计算方法中,首次提出的颗粒方程全导数离散方法,并成功运用于两相流动颗粒轨道的计算;模拟结果表明了超声换能器的长度对颗粒会聚的影响和出口流量对颗粒分离的影响。计算结果为三出口微通道颗粒分离元件的设计和应用提供参考。     

全自动固相萃取-超高效液相色谱串联质谱法测定地表水中18种头孢菌素

建立了超高效液相色谱串联质谱(UPLC-MS/MS)法测定地表水中18种头孢菌素的方法.采用全自动固相萃取技术进行前处理,地表水样经HLB固相萃取小柱富集后,用1.0％(V/V)的甲酸溶液(溶剂为甲醇)洗脱.优选BEH Shield RP18(1.7 μm,2.1 mm×100mm)色谱柱进行分离,在电喷雾正离子(ESI+)模式下电离,多反应模式(MRM)下检测,外标法定量.结果表明:18种头孢菌素在5.0～100 μg/L范围内线性关系良好,相关系数(r)均＞0.999,方法检出限为0.5～1.8ng/L,测定下限为2.0～7.2ng/L.对地表水样品进行加标回收实验,18种头孢菌素的相对标准偏差(RSD)为0.5％～14.5％,加标回收率为64.3％～92.8％.该方法自动化程度高,结果稳定可靠,适用于地表水中头孢菌素的测定.     

SPE—GC—ECD法测定水体中五种硝基苯类化合物

建立了固相萃取(SPE)-气相色谱-电子捕获检测器(GC-ECD)检测水中硝基苯类的方法。5种硝基苯类化合物的测定在一定浓度范围内线性关系良好,在高、中、低3种浓度水平下,被测物的回收率在71.6%～87.8%之间,测定结果的相对标准偏差在1.6%～9.3%之间。5种硝基苯类的方法检出限分别为0.15μg/L和0.015μg/L。结果表明,该方法适用于实际水样中硝基苯类的测定。     

地表水中SVOCs和氨基甲酸酯类农药同步萃取技术的探讨

采用大体积固相萃取富集地表水中SVOCs和氨基甲酸酯类农药,再以气相色谱-质谱和超高效液相色谱-串联质谱联用对目标物定性定量。通过优化固相萃取条件,使SVOCs在0.500 mg/L~10.0 mg/L之间,氨基甲酸酯类农药在1.00μg/L~100μg/L之间线性良好,方法检出限为0.002μg/L~0.009μg/L,加标回收率分别为70.5%~105%和78.5%~124%。用该方法测定某流域地表水,结果邻苯二甲酸酯类物质、多环芳烃类、酚类、硝基苯环类化合物等SVOCs,以及克百威、仲丁威等氨基甲酸酯类农药检出。     

湘江长沙段饮用水水源保护区持久性有机污染物调查及防治对策

采用Waters-C18固相萃取柱预处理水样,建立了7种痕量持久性有机污染物的固相萃取-气相色谱-电子捕获(SPE-GC-ECD)分析测试方法。方法的回收率均在82.0%~105.4%的范围内,相对标准偏差(RSD)小于5.5%。采用该方法对湘江长沙段饮用水水源保护区5个监测断面的水样进行分析和调查。研究发现,除饮用水水源保护区下游断面六氯苯和o’,p’-DDT未检出外;其它断面所测的POPs均有检出,且浓度在0.27~2.27 ng/L范围内。针对POPs的污染现状,提出了相应的防治对策。     

Infiltration and redistribution of LNAPL into unsaturated layered porous media

Enhanced understanding of light non-aqueous phase liquid (LNAPL) infiltration into heterogeneous porous media is important for the effective design of remediation strategies. We used a 2-D experimental facility that allows for visual observation of LNAPL contours in order to study LNAPL redistribution in a layered porous medium. The layers are situated in the unsaturated zone near the watertable and they are inclined to be able to observe the effect of discontinuities in capillary forces and relative permeabilities. Two experiments were performed. The first experiment consisted of LNAPL infiltration into a fine sand matrix with a coarse sand layer, and the second experiment consisted of a coarse sand matrix and a fine sand layer. The numerical multi-phase flow model STOMP was validated with regard to the experimental results. This model is able to adequately reproduce the experimental LNAPL contours. Numerical sensitivity analysis was also performed. The capillarity contrast between sands was found to be the main controlling factor determining the final LNAPL distribution.     

富营养浅水湖泊中新发现的磷化氢

以富营养化湖泊太湖和南京乌龙潭为研究对象,采用气液两相平衡法,配合柱前2次冷阱富集和GC/NPD法,分析了原始湖水和经过0.45靘滤膜处理的湖水,均检测到了磷化氢.原始湖水比经过0.45靘滤膜过滤的湖水中的磷化氢含量高2~14倍.表层湖水与底层湖水中磷化氢的含量变化趋势一致,且磷化氢浓度相差不大.太湖,乌龙潭中微量磷化氢的发现,对湖泊水体中磷循环的深入研究和水体富营化的防治具有积极的现实意义.     

在线固相萃取-高效液相色谱-串联质谱法测定地表水中8种全氟化合物

建立了在线固相萃取-高效液相色谱-串联质谱法（On-Line SPE-HPLC-MS/MS）检测地表水中8种全氟化合物（perfluorinated compounds,PFCs）的分析方法. 该方法用电喷雾离子源（ESI）在选定的多反应监测（MRM）负模式下确定目标化合物并使用同位素内标法定量,测定了地表水中的PFCs. 8种PFCs的样品加标回收率在82.1%—103%之间,线性范围在0.66—500 ng·L⁻¹之间,相关系数（R²）在0.991—0.998之间,精密度（RSD）在3.95%—6.29%之间,检出限（LOD）在0.20—2.43 ng·L⁻¹之间,定量限（LOQ）在0.66—8.09 ng·L⁻¹之间. 方法应用于大凌河及小清河地表水的分析,分析结果与该领域其他研究的结果一致,表明该方法具有实际应用意义.     

分子印迹技术与固相微萃取技术联用的研究进展

固相微萃取技术是一种广泛使用的样品前处理技术,涂层是固相微萃取技术的核心部分.目前商品化的涂层缺乏选择性,易受基质干扰,不适合复杂环境基质中痕量有机污染物的分析.分子印迹聚合物是一种具有强大分子识别功能的材料,具有高效的选择特异性,将其作为固相微萃取涂层,可提高其选择性,扩大其应用范围,是目前固相微萃取涂层的研究热点之一.本文介绍了分子印迹技术的基本原理,综述了近年来国内外分子印迹技术与固相微萃取技术联用的研究进展,包括分子印迹固相微萃取装置形式以及方法研究等,最后展望了分子印迹固相微萃取的发展方向.