LAS对土壤微生物生物学指标的影响及降解条件的正交实验分析

用正交实验方法研究了徐州地区4种土壤在不同组合条件下土壤微生物数量、酶活性及LAS的降解条件。结果表明,LAS对土壤细菌生长有促进作用,对真菌则有抑制作用,而对放线菌无明显影响。LAS对转氨酶和脱氢酶均有抑制作用。微生物数量波动最大的组合条件为荒土、30℃、LAS浓度50mg·kg-1、时间8d;LAS最大降解的组合条件为河土、25℃、LAS浓度20mg·kg-1、时间8d(降解率为33.2%);土壤酶活性减少最多的组合条件为麦田土、25℃、LAS浓度30mg·kg-1、时间8d(转氨酶活性减少0.0594,脱氢酶抑制率达49.58%)。另外,土壤对LAS污染的环境效应与土壤类型和性质等因素有关。     

基于OpenGL的LiDAR数据处理模块设计与实现

针对目前海量LiDAR数据处理涉及问题复杂、多数算法保密的问题,研究了基于OpenGL技术构建LiDAR数据处理模块的方法,并对模块构建过程中涉及的关键技术,包括LAS格式数据读取、基于OpenGL的LiDAR点云显示、改进的多级移动曲面拟合LIDAR数据滤波算法的实现进行了深入研究。为验证该模块处理LiDAR三维点云数据的正确性,利用该模块进行了LiDAR点云的二维显示、三维显示、滤波处理等。试验结果表明:本研究所开发的LiDAR数据处理模块能够快速、正确的显示和编辑LiDAR点云数据,且有高精度的LiDAR点云滤波结果。     

高压线电磁场强度对大孔径闪烁仪观测的影响

大孔径闪烁仪(Large Aperture Scintillometer, LAS)是测量水平距离上250~4 500 m 地表能量平衡和水热通量的仪器。在其红外波传输的过程中会受到环境因素以及下垫面属性的影响。鉴于外界条件的复杂性, 还会受到树木的阻挡以及高压线电磁场辐射等因素的影响。本文通过分析2009 年8 月~2010 年3 月在中国科学院栾城农业生态系统试验站开展LAS 观测过程中的影响因素, 研究了高压输电线电磁场对LAS 观测的影响。结果表明, 当LAS 红外光路径距高压线过近时对测定的感热通量H_LAS 影响较大, 导致计算结果与实际不符。通过计算提出了避免高压输电线电磁场干扰LAS 观测信号的安全安装距离应是保证高压输电线电磁场强度小于4.05 μT 的距离。结果可为开展同类观测试验提供参考。     

合成洗涤剂（LAS）对农作物影响的研究

本文采用水培和盆栽试验的方法，研究合成洗涤剂（ＬＡＳ）对小麦、水稻的幼苗、生育期、产量、质量以及黄瓜、萝卜的苗期影响。探讨ＬＡＳ对农作物危害的临界浓度和合理使用污水灌溉农田ＬＡＳ的允许浓度范围。     

异质下垫面显热通量动态变化及对环境因子的响应

利用2010年7月至2011年6月大孔径闪烁仪的观测数据分析了显热通量的变化规律,通过主成分分析和相关性分析,筛选出影响显热通量的主要控制因子,探讨了鹫峰站点复杂下垫面水热通量对环境因子的动态响应.结果表明:(1)鹫峰站点显热通量日变化规律与平坦(或均匀)下垫面相似,即显热通量与天气条件密切相关,具有明显的季节性变化规律.4个典型晴天均有峰值出现,从年初至年末显热通量峰值从中午11:00左右向上午偏移;秋分日显热通量波动最明显,冬至日波动较为平缓;夏至日显热通量值最大,处于波峰期,冬至日显热通量值最小,处于波谷期.(2)土壤温度、土壤含水量、空气温度、下垫面蒸散发、风速、风向以及太阳净辐射是影响显热通量传输的主导因子,且不同典型晴天的主导因子不同.(3)土壤含水量和土壤温度与显热通量具有极显著相关性,受下垫面植被组成复杂,地形起伏大等因素的影响,风向与风速与显热输送也表现出了显著的相关性.研究结果有助于加强对复杂山区显热通量规律的认识.     

表面活性剂LAS与重金属Cd复合污染对黄豆生长的影响

采用盆栽试验方法,研究了表面活性剂LAS(十二烷基苯磺酸钠)与重金属Cd单一及复合污染对黄豆生长和生理生化指标的影响。结果表明,在单一LAS污染条件下,较低浓度的LAS(≤15mg·L-1)能促进黄豆的生长,较高浓度的LAS(≥50mg·L-1)对黄豆有毒害作用。在单一Cd污染条件下,土壤中Cd浓度为5mg·kg-1和10mg·kg-1时,黄豆的生长受到严重的抑制。在同一Cd污染土壤中,随着灌溉水LAS浓度的升高,黄豆的株高、干重、叶片叶绿素含量和SOD活性都呈先升后降的趋势,当LAS浓度为50mg·L-1时,这些指标的数值最大,而MDA含量随着LAS浓度的升高呈先降后升的趋势。通过这些生长及生理生化指标的测定,可以得知低浓度LAS(≤50mg·L-1)能部分缓解Cd对黄豆的毒害。     

合成洗涤剂对水生生物的毒性效应

本文研究合成洗涤剂主要成份表面活性剂直链型烷基苯磺酸钠(LAS)对隆线溞、白鲢幼鱼的急性毒性,以及对鲤鱼胚胎发育的毒性影响和鲤鱼仔鱼的急性中毒效应。试验结果表明,LAS 对以上几种水生生物均有不同程度的毒性作用,隆线溞48小时 LC_(50)为5.26毫克/升,白鲢幼鱼96小时 LC_(50)为2.16毫克/升,鲤鱼受精卵的孵化率随着 LAS 浓度增大而降低,与对照组相比,其浓度组推迟了孵出时间。因此初步说明 LAS 对溞和鱼类是属低毒物质。本文还用加佳、白佳两种洗衣粉对隆线溞的急性毒性进行比较。     

Effects of Linear Alkylbenzene Sulfonates (LASs) in Sewage Sludge–Amended Soils on Nutrient Contents of Broccoli Plants

Abstract

Sewage sludge is used in agriculture as a fertilizer and an organic amendment to improve physical and chemical soil properties. However, sludge contains organic compounds, such as surfactants, which may be toxic in the soil–plant system. The effects on plants of linear alkylbenzene sulfonates (LAS), a group of anionic surfactants that are widely used in detergent products, have not been well defined. In this experiment, the effect of differently treated sewage sludge containing LAS on the macronutrient and sodium contents of different parts of broccoli plants (Brassica oleracea L. var. botrytis subvar. cymosa Lam.) was studied in a field experiment. Fertilizer treatments were un‐composted sewage sludge (UCSS), composted sewage sludge (CSS), and a control without fertilization (NF). The LAS levels were established across all fertilizer treatments by addition of 0, 15, or 30 g LAS m^?2 (LAS0, LAS15, and LAS30, respectively). In general, the macronutrient contents in shoots, leaves, and edible parts of broccoli were higher in plants cultivated without fertilization but with LAS. In most cases, the LAS application increased the nitrogen, phosphorus, and sodium contents of the different plant parts, whereas calcium and magnesium concentrations were reduced.     

Response of soil enzymes to Linear Alkylbenzene Sulfonate (LAS) addition in soil microcosms

Soil enzymatic activities (phosphatases, arylsulphatase and dehydrogenase) were measured in microcosm systems designed for the study of the impact of a commercial mixture of Linear Alkylbenzene Sulphonate (LAS) homologues on a xerofluvent agricultural soil. The soil microcosms consisted of glass columns filled with 800 g of dry soil which were fed with sterile commercial LAS solutions at concentrations of 10 or 50 mg l⁻¹ for periods of time up to 21 days. A soil microcosm fed with sterile distilled water was included in this study and considered as control. Our results showed that the continuous application of the anionic surfactant to soil increased the values of the enzymes acid and alkaline phosphatases and arylsulphatase. On the contrary, the dehydrogenase activity was decreased by the continuous application of 10 or 50 mg l⁻¹ LAS when compared with control microcosms. In addition, a statistically negative correlation was found between this enzymatic activity in the upper portion of the soil columns amended with LAS and the viable counts of heterotrophic aerobic microorganisms. Moreover, in order to test the influence of LAS on nutrient availability and, consequently, on bacteria populations and soil biological activities, phosphate concentration was regularly determined in the microcosm leachates. The phosphate concentration tested in the leachate of the microcosm continuously amended with 50 mg l⁻¹ LAS solution was significantly lower than the concentrations detected in the leachate of the microcosms continuously amended with 10 mg l⁻¹ LAS throughout the experiment.     

直链烷基苯磺酸钠超声降解的正交优化及反应机理

[目的]采用正交设计优化直链烷基苯磺酸钠（LAS）的超声降解条件,并探讨了其反应机理。[方法]考察了超声频率、超声功率、变幅杆直径和溶液初始pH值对LAS降解效果的影响。对原样及超声降解后的样品进行红外光谱分析和化学分析。[结果]正交设计试验表明,超声降解LAS为一级动力学反应;影响LAS降解的各因素显著性次序为：超声功率〉溶液初始pH值〉变幅杆直径〉超声频率。其中,低频范围内LAS降解率随频率的增加而逐渐降低,在低频条件下超声降解效果最好;大功率超声有利于LAS降解;变幅杆直径对LAS降解率的影响显著。变幅杆直径越大,降解率越高;溶液初始pH值增加,LAS降解率降低,酸性条件有利于LAS降解。红外光谱分析和化学分析结果表明,LAS的超声降解主要得益于空化泡气液界面上和本体溶液内部与空化效应产生的强氧化剂H2O2及具有高度化学活性的.OH进行自由基氧化反应。[结论]该研究得到了LAS超声降解的机理,得出一些有益的结论,为进一步研究工作奠定了基础。