Simultaneous removal of cyanobacterial blooms and production of clean water by coupling flocculation with a rotary drum filter

Environmental Science and Pollution Research - A mechanical harvesting technology based on coupling flocculation with a rotary drum filter (RDF, 35-μm) was applied to remove cyanobacterial...     

技术变化模拟及其在气候政策模型中的应用

技术变化是应对气候变化问题的关键。对技术变化的模拟和分析能够识别技术变化的作用．在评估减排成本以及确定减排目标时起到重要作用。但是早期的气候政策模型通常将技术变化视为非经济的外生变量，因而无法对技术变化的起因和效果做深入分析。近年来的气候政策模型则开始逐渐利用内生方法模拟技术变化。在介绍内生技术变化的概念及与传统的外生技术变化的区别的基础上，重点介绍和评述研发投入和技术学习这两种主要的内生技术变化模拟方法的原理、特点以及如何在不同的气候政策模型中得到应用。但是现有建模方法无法表征技术变化过程中的动态性、不确定性等特征，因而传统的建模方法需要扩展到一个更为综合的框架并需要更坚实的实证研究基础上。基于该框架介绍内生技术变化模拟方法的未来可能拓展。     

可持续旅游及其区域实现途径探讨—以井冈山风景名胜区为例

可持续旅游是 80年代中期以后提出的关于旅游业发展的新思想。经过十多年的不断拓展深化 ,已经得到世界各国的广泛认同 ,并作为跨世纪旅游业发展的战略指导思想。本文从可持续旅游的由来和对可持续旅游内涵实质的界定角度出发 ,结合可持续旅游实现途径的探讨 ,以井冈山风景名胜区为例 ,对风景区旅游业可持续发展进行了深入的探讨 ,为景区的发展规划提出了战略性构想 ,以期能对井冈山风景名胜区旅游资源的可持续利用和旅游业的可持续发展起到抛砖引玉的作用     

On Index System and Quantitative Assessment of Eco-cities： A Case Study on Urban Agglomeration of the Yangtze Delta

Urban agglomeration of the Yangtze Delta （UAYD）, one of the most developed regions of China, has witnessed an increasing prevalence in building ecological cities when the ecological cities are pursued by many modem cities, and great achievements have been made in this regard. It is inevitable, however, that certain problems exist during the construction of ecological city, which include but not limited to non-harmonious development of urban complex ecosystem, and the difficulty in quantifying eco-city construction or incomplete quantification in assessing the construction of present and future eco-city. Based on the analysis on social-economic conditions and regional conditions of the UAYD, this paper attempts to set up an index system of eco-cities combining with local characteristics, and to adopt the indices of eco-city, urban harmony, and eco-city colligate to evaluate the ecological level, urban harmonious development and eco-city construction of cities within the UAYD. Results indicate that among 15 cities in UAYD, Suzhou City ranks the highest in terms of eco-city construction, whereas Nantong ranks relatively lower; sustainable eco-city construction is possible only when cities are developed in every respect of harmony.     

Study on cooperative strategies of rural water environment governance PPP project between companies and farmers from the perspective of evolutionary game

Environment, Development and Sustainability - The PPP mode of rural water environment governance was conducive to attracting social capital for giving full play to the decisive role of the market...     

基于在线监测+模型的海绵城市建设径流水量控制效果研究

以青岛市海绵城市典型项目区为研究区,通过收集、整理和概化汇水区资料,构建了研究区降雨径流模型——SWMM模型。利用2018年雨季的降雨-径流实时监测数据,进行了模型关键参数的率定和模型验证,研究了海绵城市建设在削减径流量、增加入渗与滞蓄雨量方面的定量效果。结果显示:海绵改造后,不同降雨强度下形成径流的雨量占总雨量的平均比例由56%下降至29%;下渗雨水的平均比例由40%增加至60%,滞蓄深度由0.63 mm增加至5 mm。海绵改造前后研究区场降雨径流总量控制率变化显著,当以1~10年一遇的短历时（120 min）设计降雨作为模型边界条件进行模拟时,海绵化改造后场次降雨径流总量控制率提高了26%~34%,认为研究区基本达到了海绵城市关于水量控制的建设要求。     

Dynamic nano-Ag colloids cytotoxicity to and accumulation by Escherichia coli: Effects of Fe3+, ionic strength and humic acid

Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials, and thus, the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle:Ag⁺ ratios. Our recent research found that the cytotoxicity of PVP-Ag nanoparticles is attributable to Ag particles alone in 3 hr bioassays, and shifts to both Ag particles and released Ag⁺ in 48 hr bioassays. Herein, as a continued study, the cytotoxicity and accumulation of 50 and 100 nm Ag colloids in Escherichia coli were determined dynamically. The cytotoxicity and mechanisms of nano-Ag colloids are dynamic throughout exposure and are derived from both Ag ions and particles. Ag accumulation by E. coli is derived mainly from extracellular Ag particles during the initial 12 hr of exposure, and thereafter mainly from intracellular Ag ions. Fe³⁺ accelerates the oxidative dissolution of nano-Ag colloids, which results in decreasing amounts of Ag particles and particle-related toxicity. Na⁺ stabilizes nano-Ag colloids, thereby decreasing the bioavailability of Ag particles and particle-related toxicity. Humic acid (HA) binds Ag⁺ to form Ag⁺-HA, decreasing ion-related toxicity and binding to the E. coli surface, decreasing particle-related toxicity. HA in complex conditions showed a stronger relative contribution to toxicity and accumulation than Na⁺ or Fe³⁺. The results highlighted the cytotoxicity and mechanism of nano-Ag colloids are dynamic and affected by environmental factors, and therefore exposure duration and water chemistry should be seriously considered in environmental and health risk assessments.     

Metabolomic modulations in a freshwater microbial community exposed to the fungicide azoxystrobin

An effective broad-spectrum fungicide, azoxystrobin (AZ), has been widely detected in aquatic ecosystems, potentially affecting the growth of aquatic microorganisms. In the present study, the eukaryotic alga Monoraphidium sp. and the cyanobacterium Pseudanabaena sp. were exposed to AZ for 7 days. Our results showed that 0.2–0.5 mg/L concentrations of AZ slightly inhibited the growth of Monoraphidium sp. but stimulated Pseudanabaena sp. growth. Meanwhile, AZ treatment effectively increased the secretion of total organic carbon (TOC) in the culture media of the two species, and this phenomenon was also found in a freshwater microcosm experiment (containing the natural microbial community). We attempted to assess the effect of AZ on the function of aquatic microbial communities through metabolomic analysis and further explore the potential risks of this compound. The metabonomic profiles of the microcosm indicated that the most varied metabolites after AZ treatment were related to the citrate cycle (TCA), fatty acid biosynthesis and purine metabolism. We thereby inferred that the microbial community increased extracellular secretions by adjusting metabolic pathways, which might be a stress response to reduce AZ toxicity. Our results provide an important theoretical basis for further study of fungicide stress responses in aquatic microcosm microbial communities, as well as a good start for further explorations of AZ detoxification mechanisms, which will be valuable for the evaluation of AZ environmental risk.     

达里诺尔湖水体DOM荧光特征及其来源解析

达里诺尔湖（简称“达里湖”）是内蒙古自治区高原地区重要的生态屏障,探究达里湖水质状况及污染来源,对加强流域水环境治理、改善水环境质量具有十分重要的意义.于2018年9月及2019年6月对湖水进行采样,并通过三维荧光光谱结合PARAFAC（平行因子分析）模型,探究达里湖水体DOM（溶解性有机质）来源及其与水质的关系.结果表明:①达里湖水体中pH较高,ρ（DOC）（DOC为溶解性有机碳）、ρ（NH₄+-N）、ρ（TP）相对较高,均超过GB 3838—2002《地表水环境质量标准》Ⅴ类水质标准限值.②水体中DOM含4种荧光组分.夏季水体DOM主要分布于河流入湖口附近,其中,类腐殖质荧光组分（紫外区类富里酸和可见区类富里酸）占总组分的62.93%,类蛋白类荧光组分（类色氨酸和类酪氨酸）占总组分的36.07%;秋季水体DOM主要分布于东南侧,其中,类腐殖质荧光组分占总组分的40.52%,类蛋白类荧光组分占总组分的59.48%.③达里湖采样点荧光参数表明,达里湖DOM自生源特征较强,腐殖化程度较低.类腐殖质荧光组分与ρ（DOC）、ρ（Chla）均呈正相关,类色氨酸荧光组分与pH呈正相关,类络氨酸与ρ（DTN）、ρ（NH4+-N）、ρ（DTP）均呈正相关.研究显示,达里湖DOM具有陆源与生物源双重特性,DOM的形成与微生物、细菌、浮游生物的生命活动密切相关.      

长江中下游环境DNA宏条形码生物多样性检测技术初步研究

长江生物多样性在人为影响下面临严重威胁,物种监测是生物多样性保护的基础,为完善长江水生态监测体系,实现高效无损伤的物种监测,在长江中下游干流3个江段（新滩、安庆和芜湖）采集水样,建立长江水样环境DNA宏条形码物种检测体系并评估其有效性.结果表明:①长江中下游环境DNA宏条形码检测到32个物种,包括20种鱼类、1种水生哺乳动物（长江江豚）和11种陆生动物,其中鱼类物种包括鲤形目、鲇形目、鲈形目和鲱形目,其种数占鱼类总种数的比例分别为60%、25%、10%和5%.②长江中下游渔获物中资源量居首位的鲤形目在环境DNA调查中序列数最多,占鱼类总序列的96.2%,其次为鲱形目（占比为3.5%）,鲇形目和鲈形目占比较低,分别为0.2%和0.1%,4个类目序列相对丰度与渔获物种资源量组成差异较大.③环境DNA调查次数约占传统渔获物调查次数的几十至几百分之一,采样时间不足努力量最少的渔获物调查的1%,检测到的鱼类种数为传统调查总数的31%~49%.④安庆采样点位于长江中下游长江江豚密度最高的江段,其环境DNA检出率和序列相对丰度在3个采样点中均最高.研究显示:长江水样环境DNA包含水陆复合生态系统的生物多样性信息,利用水样环境DNA宏条形码可检测不同类群的水生和陆生物种;对于鱼类物种检测,环境DNA宏条形码比传统调查方法效率更高,可对传统调查结果进行补充;环境DNA宏条形码生物多样性检测主要受分子标记体系和核酸序列数据库限制,获取全面的物种多样性和资源量信息需要对检测分析方法进行进一步完善.