Metal accumulation in intertidal litter through decomposing leaf blades, sheaths and stems of Phragmites australis

Metal contents of decomposing leaf blades, leaf sheaths and stems of common reed (Phragmites australis) were monitored by a litter bag method on the sediment of an intertidal brackish marsh in the Scheldt estuary (The Netherlands). On monthly intervals, two litter bags were retrieved from the marsh during 9 months for both leaf blades and sheaths and during 16 months for stems. All samples were dried, weighed and analysed for ash and Cd, Cu, Cr, Ni, Pb and Zn contents. Most concentrations increased considerably during the decomposition. Generally, also a very important net metal inflow into the litter bags could be observed. The inflow was highest for leaf blades. High correlations between ash contents and metal concentrations for leaf blades suggest that the increase of leaf blade metal contents can be due to physicochemical sorption of dissolved metals and an important infiltration of mud particles, which were not removed by rinsing the leaf blades with distilled water preceding the analyses. For stems, smaller amounts of inflowing ash and even outflowing ash amounts were found, which suggests that inflow of inorganic particles is not the major factor determining metal accumulation by stems on medium term. Ergosterol concentrations in stem tissue however proved to be correlated with metal contents, which suggests a significant role of fungal litter colonizers in metal accumulation. For leaf sheaths, the effects of physicochemical sorption, infiltration of mud particles and incorporation by microbial litter colonizers do not seem to be as pronounced as for stems and leaf blades.     

二氧化硫与环己烷的光化学反应

本文研究了ＳＯ２与环己烷在无氧及有氧体系中的光化学反应，观察到了白色烟雾有生成并凝聚，利用ＧＣ和ＧＣ／ＭＳ法确定了部分反应产物－环烯烃、醇、酮、二元酸酯、呋喃衍生物以及硫酸二甲酯等有机化合物，探讨了影响光化学反应的几种因素及反应机理。     

二氧化硫与1—己烯的光化学反应动力学

利用ＧＣ／ＭＳ方法研究了ＳＯ２与１－己烯在无氧和有氧体系中光化学反应动力学，确定了ＳＯ２与１－己烯光化学反应的级数，给出了２９３－３３３Ｋ温度范围内总的反应速度常数Ｋ，以及Ｋ与温度的关系、反应的活化能和指前因子。另外，对反应物己醛和２－己酮的生成反应速度常数及其活化能也进行了计算和讨论。     

响应面方法优化光催化降解抗生素类污染物过程研究

近年来抗生素类污染物对环境的影响及其生态毒性日益引起广大研究者的关注。对TiO2光催化降解典型抗生素类污染物磺胺二甲嘧啶（SMT）进行了研究。采用中心组合设计方法（CCD）进行试验设计,使用响应面方法（RSM）对光催化过程中的影响因素（TiO2浓度、初始磺胺二甲嘧啶浓度、双氧水浓度）进行了探讨和分析,并对反应过程进行了优化。优化结果表明,最佳反应条件为：TiO2浓度1.74 g/L、初始磺胺二甲嘧啶浓度20.0 mg/L、双氧水浓度106.28 mg/L,在优化条件下的磺胺二甲嘧啶光催化实际去除率为83.6%。响应面方法能够优化光催化条件,预测光催化结果,有利于优化光反应器的设计,对于工程化光催化水处理技术的发展具有一定的参考价值。     

东北严寒地区村镇环境现状调查研究

在城乡一体化发展背景下,农村内部现代化进程不断加快,而与之配套的社会公共服务设施与管理体制尚不健全,使得农村环境污染不断加剧.经问卷调研,东北严寒地区村镇环境突出的问题是水体和空气污染严重,垃圾围村现象普遍,工业企业生产及道路交通使得噪声污染加剧,工业企业污染较重.探究环境污染形成机制包括:农村粗放的经济发展模式、农民生活形式现代化和模式传统化的矛盾、农民环保意识薄弱以及城乡二元化体制结构使得东北严寒地区村镇环境不断恶化.文章最后提出了针对性的对策建议.     

冷冻分离法处理难降解有机废水的研究

以无机水样、溴氨酸溶液、U llm ann缩合反应生产废水及垃圾渗滤液为研究对象,考察了在人工条件下冷冻法处理无机离子和有机污染物的效果和差别。结果表明:在人工冷冻条件下,无机离子、溴氨酸的去除率均可达到80%~90%以上,并受冷冻时间、初始浓度、污染物自身结构特性等因素影响;而对于无机离子和有机污染物混合的实际有机废水,其去除率相对较低,为70%~80%左右,需要与其他工艺组合,以提高废水的处理效率。     

Removal and recovery of uranium (VI) from aqueous solutions by residual sludge and its biochars

Environmental Science and Pollution Research - The removal and recovery of uranium (VI) from water solutions are critical for energy and environmental security. In this study, hydrochar at 100,...     

农药助剂对蚯蚓(Eisenia foetida)的急性毒性

为评价农药助剂对土壤生物的毒性效应,分别采用滤纸接触法和人工土壤法测定了不同类别农药助剂对赤子爱胜蚓(Eis enia foetida)的急性毒性.结果表明:19种非离子表面活性剂中,烷基酚聚氧乙烯醚与脂肪醇聚氧乙烯醚毒性较高,滤纸法48 h-LC50为7.630 ～ 39.65μg·cm-2,人工土壤法14 d-LC50为876.5 ～2 786.6 mg· kg-1,其它类型非离子表面活性剂毒性较低.5种阴离子表面活性剂中,十二烷基硫酸钠、十二烷基苯磺酸钙毒性高于木质素磺酸钠、木质素磺酸钙、亚甲基双萘磺酸钠,滤纸法48 h-LC50为6575 ～ 41.89 μg· cm-2,人工土壤法14 d-LC50为1 195.0～1 911.7 mg·kg-1.13种溶剂中,二甲苯、乙苯、甲苯、正丁醇、环己酮表现出较高的毒性,滤纸法48 h-LC50为6.587 ～ 57.62 μg ·cm-2,密封人工土壤法48 h-LC50为181.9 ～781.5 mg·kg-1.采用两种方法测得的5种填料高岭土、白炭黑、硅藻土、凹凸棒土和轻质碳酸钙的毒性均较低.采用两种方法测得的毒性系统偏差接近,重现性均较好,并且滤纸接触法测得的毒力高于人工土壤法.     

Methodology for an urban ecological footprint to evaluate sustainable development in China

The ecological footprint (EF) is a method for measuring sustainable development through ecological impact. A methodology is presented for predicting urban ecological footprints. Urban energy use and natural resource consumption were analyzed to calculate an EF based on land type (arable, pasture, forest, fossil energy land, built-up area and water area) and consumption (food, housing, transportation, goods, services and waste). The result was then compared with the local ecological carrying capacity to develop criteria for sustainable ecological footprints. Case studies of four cities in China (Guangzhou, Ningbo, Suzhou and Yangzhou) illustrate the urban EF approach. The time series of EF in a case study of Guangzhou for 1991–2001 was analyzed and the consumption–land-use matrix of urban EF was established. The results show that the cities are ecologically unsustainable, with average ecological conflicts per capita of more than 2 ha. The urban EF method is useful to measure urban sustainable development and provides policy proposals for decision-making. However, the EF method still has limitations and weaknesses.     

The effect of macrophytes on retention times in a constructed wetland for wastewater treatment

Retention times of treated water in a constructed wetland (CW) with horizontal subsurface flow were determined both in the vegetative and non-vegetative periods of 2005. Tracer experiments were performed using fluorescein, an organic compound detectable at extremely low concentrations. Nominal and tracer retention times were determined and compared. Winter tracer retention time (TRT 194 h) and nominal retention time (nHRT 190 h) were nearly exactly equal, while summer TRT (335 h) was approximately twofold higher than nHRT (158 h). Residence time distribution function (RTD) was used to compare retention times obtained for the vegetative and non-vegetative periods. The obtained results document a significant influence of dense common reed vegetation on retention characteristics of the studied system. Common reed can convert a significant volume of water from liquid to gas via evapotranspiration (ET) and thus prolong water retention times in the system. This is very important both technically and ecologically. Longer retention times mean a longer time for microbiological decay of wastewater. Water converted from liquid to gas causes cooling of the microclimate, which is very important, especially in intensively cultivated areas with a lack of water.