菲胁迫下湿生植物美人蕉(Canna indica)对斜生栅藻(Scenedesmus obliquus)生长的影响

多环芳烃有机污染物的环境问题日益严重,亟待需求从群落及生态系统的角度进行毒理学复合危害效应的研究。本文采用以美人蕉(Canna indica)种植根区水培养斜生栅藻(Scenedesmus obliquus)的方式,观察菲胁迫下其生长的变化。结果表明,美人蕉种植根区水对斜生栅藻生长具有化感效应,且表现为"低促高抑"的现象。而在菲胁迫下,种植根区水比例为15%和30%时随着菲浓度的增加,生长促进作用增强,且在菲浓度为1 mg·L-1出现最高值;在100%种植根区水时随着菲浓度的增加生长抑制作用增强。说明,菲胁迫使美人蕉种植根区水对藻类的化感效应增强。进行逻辑斯谛生长拟合发现,30%、1 mg·L-1处理组种群内禀增长率最高,斜生栅藻种群出现暴发增长的生态风险最大。     

Separation of chlorinated hydrocarbons and organophosphorus, pyrethroid pesticides by silicagel fractionation chromatography and their simultaneous determination by GC-MS

A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons(CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, was developed in this study. This method was achieved by optimizing the fraction cut-off volume of elution and different solvents. Using fully activated silica gel and cut-off CHCs collection after 10ml 10% dichloromethane (DCM) in n-hexane passing through the column resulted in satisfactory separation of CHCs and organophosphorus, pyrethroid pesticides. This procedure had a higher reliability for CHCs than for organophosphorus, pyrethroid pesticides, because there is a relatively reliable recovery for CHCs. This approach is less expensive due to reducing sample pre-treatment time and solvent consumption.     

Degradation of 4-CP in an internal electrolysis system

The characteristic and mechanism of parachlorophenol (4-CP) degradation in an internal electrolysis system were investigated. The degradation rate of 4-CP was higher in acid solution than that of in neutral or alkaline solution. Addition of activated carbon could make 4-CP easier be degraded by the surface contact catalysis. The dissolved oxygen in solution could take part in the electrode reaction and intensify the degradation of 4-CP. By the analysis of intermediates of degradation of 4-CP, it could be conferred that 4-CP was broken through the bond beside hydroxy firstly, then the bond beside chloride was broken and the chloride was dechlorinated simultaneously. Most intermediate products were glycerine, ethane diacid and acetic acid, while very few 1, 4-butanedial and alcohols were found.     

潮汐流动平均离散的分析与计算

利用二维潮汐流动纵向流速任意分布下离散系数的计算公式,对几种典型的流速分布建立了潮平均离散系数D_us与分时段按恒定流处理所得的潮平均离散系数D_s之间的关系。通过水槽试验对计算结果进行了定性验证。把这种方法应用于珠江,根据实测的流速分布资料,由恒定流的剪切离散结果获得了广州河段潮平均的离散系数。     

合成有机物对厌氧消化抑制的可逆性机理分析

总结出抑制性合成有机从厌氧化消化系统内清除的４种主要作用算什么,即厌氧降解作用,厌氧污泥吸附作用、挥发作用和随出水流出作用。从厌氧消化中各大类微生物之间相互平衡、协同作用的关系,分析了合成有机物对厌氧消化抑制的可逆性机理,并提出了抑制性合成有对厌氧消化抑制的可逆性机理图式。     

RTCA与CCK-8法用于检测柴油废气颗粒物致支气管上皮细胞毒性的比较研究

运用实时无标记细胞分析系统(RTCA)和Cell Counting Kit-8(CCK-8)法分别检测柴油废气颗粒物(DEP)致支气管上皮细胞(HBE)细胞毒性,从而对2种方法进行比较研究.分别以浓度为0、3.5、7、14、28和56 mg·L-1 2种柴油废气标准参考颗粒物(Standard Reference Material 1650b,SRM 1650b;Standard Reference Material 2975,SRM 2975)对 HBE 细胞进行暴露处理,分别暴露6、12、24和48 h后,检测不同DEP致HBE细胞毒性,比较各组之间细胞存活率或标准化细胞指数(normalized cell index,NCI)值的差异,考察2种方法的优缺点.并用细胞凋亡实验检测各差异组之间的凋亡率.在相同染毒浓度及暴露时间,与SRM 1650b相比,SRM 2975对HBE细胞的毒性更强.在RTCA检测DEP致HBE细胞毒性时,低浓度DEP组的NCI值已经表现出与对照组有统计学差异(P＜0.05),而相同时间条件下,CCK-8法在更高浓度的DEP组才检测出显著的细胞活性下降(P＜0.05).且由细胞凋亡实验证实,与对照组相比,低浓度DEP组的细胞凋亡率已经有统计学差异.相对于CCK-8法,RTCA更适用于检测DEP致贴壁HBE细胞毒性.CCK-8法更适用于检测DEP致悬浮细胞的细胞毒性或与气液暴露装置联用时的贴壁/悬浮细胞毒性.     

留民营生态农业系统的结构与能量流和生态效率的计算

留民营生态农业系统是一个包括农、林、牧、副、渔各业生产的社会经济-自然复合生态系统。在该系统中,既要发展生产,全面提高农民的生活质量,并为城市提供丰富的农副产品,又要保护生态环境,避免生产发展带来的污染与生态环境的破坏,达到经济效益、环境效益与社会效益的统一。因此,对系统     

Evaluation of cationic polyacrylamide-based hybrid coagulation for the removal of dissolved organic nitrogen

Dissolved organic nitrogen (DON) is an important component of aquatic environment of which amount impacts water quality. Thus, removal of DON has attracted wide attention. At present, it is difficult for common coagulation to remove DON from the aquatic environment. The cationic polymers can help to improve the removal efficiency of DON to some extent, but the underlying mechanism of the ascension is not clear. In order to grasp its removal behavior and further improve the removal efficiency of DON in the future, we evaluated the effect of a hybridized coagulant of polyacrylamide with iron-based coagulant on removal of aquatic DON. A higher floc growth rate (119.82 μm/min) and recovery factors (26.96) were found in the hybrid coagulation. The parameters affecting the DON and the dissolved organic carbon (DOC) included the molar ratio of Zn to Fe (n_Zn/n_Fe), CPAM content, and molar ratio of OH to Fe (n_OH/n_Fe): n_Zn/n_Fe had a larger influence in DON removal than CPAM content; CPAM had a larger influence in the DOC removal; n_OH/n_Fe played a moderate effect between CPAM and n_Zn/n_Fe. Mutual effect of hybrid coagulants indicated the colloidal species to be helpful in enhancing DOC and DON removal. Other parameters affecting coagulation performance included the pH: the estimated maximum DON removal efficiency occurred at pH 6, DOC removal efficiency at pH 8. The above results found in this study showed that DON removal was affected by the ingredient and the species composition of the hybrid coagulant, and the water environmental parameter. The enhanced efficiency of DON removal in the presence of CPAM was mainly attributed to the increased adsorption-bridging and sweep-floc.     

城市河流生态系统健康及其评价

介绍了城市河流生态系统健康的概念、内涵、特征以及研究尺度,阐述了河流生态系统健康评价的方法和评价指标体系,并指出了河流健康评价方法的发展方向,以及对我国河流管理的现实意义.     

春季高羊茅草坪节肢动物群落动态研究

从群落生态学的角度对草坪节肢动物群落动态变化作了初步探讨.通过对黄山学院校内草坪的调查,获得了关于草坪节肢动物群落的组成、个体数量及其物种数等数据.通过数据分析,得出草坪节肢动物群落是由植食类亚群落、捕食类亚群落、寄生及中性亚群落组成;对物种丰富度进行分析,为草坪害虫的综合防治提供了科学的理论依据.