农村水环境保护与经济可持续发展

我国的生态环境问题 ,如水土流失、草场退化、沙漠化、盐渍化等问题 ,归根到底还是农村水环境问题。本文分析了农村水环境保护、高效利用水资源的紧迫性 ,以及影响农村生态系统可持续性的因素和保护、改善农村水环境的主要措施 ;认为加强农村水环境保护及其持续发展能力的建设是我国整个社会特别是农村经济可持续发展的基本保障     

生态活度生态位--理论、方法及其应用

“生态活度生态位（Eco-vigor Niche）”是对生态位概念和理论的发展．它描述区域生态系统中一个占据特定空间位置的复合生态系统单元（或景观斑块）．在与其它单元相互作用过程中所形成的相对地位与作用。在由自然生态活度坐标和社会经济生态活度坐标构成的二维空间中．生态活度生态位可以用二维空间中的矢量表达。该矢量的“长度”意味着,生态系统单元的资源优势程度与提供生态服务的能力;矢量的“方向”则意味着该生态系统单元所具有的．由其社会经济生态活度和自然生态活度相比较而体现出来的属性．反映出该单元在区域复合生态系统中的性质和角色。“生态活度生态位”可以表达区域生态系统内的空间分异特征。反映各生态单元在区域内扮演的角色．判断各单元在区域生态系统中的功能定位．为生态区划、生态规划、土地利用规划等提供依据。     

基于组件式GIS的重大危险源管理系统的设计与开发

基于组件式GIS技术建立城市重大危险源管理系统。概述了组件式GIS的技术特点 ,结合当前城市重大危险源管理的要求 ,利用该技术从系统结构、系统功能、数据库结构等方面完成城市重大危险源管理信息系统的设计。实现了反映城市重大危险源数据的图层的建立以及重大危险源的评价分级功能 ,并提出了危险源的专题图分析和危险事故分析方法 ,完成了城市重大危险源管理系统的开发。     

基于模糊聚类关联分析法的煤与瓦斯突出程度分析

运用模糊聚类分析方法对煤与瓦斯突出的样本集合进行分类,建立了不同突出程度的模糊模式.用关联分析确定待分析样本与模式的关联程度,以此预测预报样本的煤与瓦斯突出危险程度.实例分析表明,与模糊聚类分类后、将模式与待预报样本组成新样本集合进行聚类分析并以此分类结果进行预报的方法相比,这种预报方法不仅可靠程度高,而且能定量描述待报样本与模式的亲和程度.     

活性污泥性质对短期膜污染影响的解析研究

采用统计分析方法研究了16种不同性质活性污泥混合液对膜生物反应器膜污染的影响机理.结果表明,胞外聚合物(extracellular polymeric substances,EPS)、溶解性有机物(soluble microbial products,SMP)、上清液胶体颗粒(suspended solids insupernatant,SS_s)、污泥混合液粘度(μ)、相对疏水性(relative hydrophobicity,RH)、Zeta电位(Zeta potential)均对膜生物反应器膜渗透性能有显著的影响作用,其与膜污染阻力的皮尔逊相关系数r_p分别为:0.898、0.712、0.810、0.691、0.837、-0.881;同时发现,胞外聚合物是影响活性污泥中溶解性有机物含量(r_p=0.682)、污泥粘度大小(r_p=0.633)、上清液胶体颗粒含量(r_p=0.783)、Zeta电位(r_p=-0.953)及相对疏水性大小(r_p=0.877)的主要因素;在活性污泥性质中胞外聚合物是影响膜污染的根本原因,是膜生物反应器膜污染的重要影响因素.     

有机改性粘土去除赤潮生物的机制研究

研究了季铵化合物改性粘土的制备条件对其去除赤潮藻效果的影响,探讨了该粘土体系高效除藻的机制.实验表明,十六烷基三甲基铵(HDTMA)可以有效地提高粘土的絮凝能力,同时HDTMA改性粘土中含有亚稳态HDTMA,增加了该改性粘土对赤潮生物的灭杀能力.改性粘土去除赤潮藻的能力与所吸附季铵化合物的杀藻能力、吸附量正相关,当老化时间延长、吸附季铵化合物稳定性增强时改性粘土除藻能力大大降低.结构不同的粘土对于吸附HDTMA的稳定化产生的空间阻力不同,在吸附量相同的情况下3层结构的蒙脱土中会有更多的亚稳态HDTMA产生;由于同离子效应,反应介质中高价金属阳离子的存在提高了亚稳态HDTMA的量,因此相应的改性粘土具有更高的赤潮藻去除能力.在60℃条件下吸附的HDTMA会更有效地占据粘土中的阳离子交换位,达到稳定态;而升高或降低温度都会有利于亚稳态HDTMA的出现,相应的改性粘土具有更高的赤潮藻去除能力.     

Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coating samples and surficial sediments in the Songhua River, China

Natural surface coating samples （NSCSs） from the surface of shingles and surficial sediments （SSs） in the Songhua River, China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals （Fe, Mn, Zn, Cu, Pb, and Cd） using the modified sequential extraction procedure （MSEP）. The results show that the differences between NSCSs and SSs in Fe fi＇actions were insignificant and Fe was dominantly present as residual phase （76.22% for NSCSs and 80.88% for SSs） and Fe-oxides phase （20.33% for NSCSs and 16.15% for SSs）. Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase （48.27%） and that in SSs present as residual phase （45.44%）. Zn, Cu, Pb and Cd were found dominantly in residual fractions （〉48%）, and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter （OM）, and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.     

Degradation of 2,4-dichlorophenoxyacetic acid in water by ozone-hydrogen peroxide process

IntroductionAt present, several types of organic pollutantsreferred to as environmental endocrine disruptors(ED) have been suggested to be associated withabnormal sexual development (Hu, 2000). It wasreported that the ED led to the decline of reproductive…     

Dissipation of chlorpyrifos in pakchoi-vegetated soil in a greenhouse

The dissipation of chlorpyrifos in pakchoi-vegetated soil was investigated in the summer and autumn in a greenhouse and field, respectively. The dissipation of chlorpyrifos in pakchoi-grown soil was comparatively described by fitting the residue data to seven models （lst-order, 1.5th-order, 2nd-order, RF lst-order, RF 1.5th-order, RF 2nd-order, and bi-exponential or two-compartment models）. Statistical analysis was performed using the SPSS 11.5 statistical package. The bi-exponential model was selected as the optimal model according to the coefficient of determination r^2. The dissipation half-lives （DT50） of chlorpyrifos in pakchoi-vegetated soil at the recommended dose in the summer and autumn, calculated by the bi-exponential model, were 0.6 and 1.2 d in a greenhouse, 0.4 and 1.0 d in a field, respectively; the corresponding values at double dose were 1.2 and 2.1 d in a greenhouse, 0.5 and 1.3 d in a field, respectively. The kinetic data indicate the dissipation of chlorpyrifos in pakchoi-grown soil in a greenhouse is slower than that in a field, and dissipates slower in the autumn than in the summer.     

不同氮源和曝气方式对淡水藻类生长的影响

利用水族箱微宇宙研究了2种氮源水体中不同曝气条件对藻类生长的影响.试验使用铵态氮(NH₄⁺-N)和硝态氮(NO₃^--N)作为氮源,每种氮源水体分别设置不曝气、连续曝气、昼间曝气和夜间曝气4个处理.结果显示:试验初期以NH₄⁺-N为主要氮源的水体中藻类生长明显好于以NO₃^--N为主要氮源的水体.试验后期则以NO₃^--N为主要氮源的藻类生长情况更好.连续曝气对于2种氮源水体中藻类生长有着不同的影响;昼间曝气对2种氮源的藻类生长影响不大;而夜间曝气对藻类生长有明显的抑制作用.NH₄⁺-N含量较高的水体中蓝藻容易成为优势种,而NO₃^--N含量高的水体中则以绿藻为主.不同曝气条件下藻类优势种没有明显差别.