Characterization of odorants in contrasting ecotypes of Lake Taihu: algae-dominated versus macrophyte-dominated zones

Environmental Science and Pollution Research - Globally, odorant incidents are occurring at an increasing frequency, magnitude, and duration under the dual influences of eutrophication and climate...     

2014-2017年四川盆地与京津冀地区冬季空气停滞特征及大气质量改善评估对比分析

对2014-2017年四川盆地和京津冀地区气象数据和污染物浓度数据进行综合评估,在原有全球空气停滞日判别标准基础上发展出本地化空气停滞指数阈值,并以提高两个区域空气质量优良天数为目的建立模型,计算各城市空气停滞发生时PM_2.5污染上限浓度参考值.本研究得出,四川盆地和京津冀地区本地化空气停滞日判别标准分别为地面风速 < 2.5 m·s^-1、边界层高度 < 500 m和地面风速 < 3 m·s^-1、边界层高度 < 300 m.四川盆地冬季空气停滞发生频率四周高,中心小,空气停滞对空气质量的影响西部高于东部;京津冀中部和南部空气停滞频率发生高,空气停滞对空气质量的影响呈现显著的南北差异.四川盆地以成都为中心城市群及京津冀中部和南部地区的高污染排放强度和高空气停滞频率导致重污染事件的频发.本文对我国两个冬季重污染高发的区域进行深入研究,更为客观、量化地评估4年来区域空气质量实际改善程度并初步建立空气质量目标管理模型,以期为区域空气质量达标管理提供可靠的科学依据.     

Characterization of halogenated DBPs and identification of new DBPs trihalomethanols in chlorine dioxide treated drinking water with multiple extractions

Chlorine dioxide(ClO_2) is a widely used alternative disinfectant due to its high biocidal efficiency and low-level formation of trihalomethanes and haloacetic acids. A major portion of total organic halogen(TOX), a collective parameter for all halogenated DBPs, formed in ClO_2-treated drinking water is still unknown. A commonly used pretreatment method for analyzing halogenated DBPs in drinking water is one-time liquid–liquid extraction(LLE), which may lead to a substantial loss of DBPs prior to analysis. In this study, characterization and identification of polar halogenated DBPs in a ClO_2-treated drinking water sample were conducted by pretreating the sample with multiple extractions. Compared to one-time LLE, the combined four-time LLEs improved the recovery of TOX by 2.3 times. The developmental toxicity of the drinking water sample pretreated with the combined four-time LLEs was 1.67 times higher than that pretreated with one-time LLE.With the aid of ultra-performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, a new group of polar halogenated DBPs, trihalomethanols,were detected in the drinking water sample pretreated with multiple extractions; two of them,trichloromethanol and bromodichloromethanol, were identified with synthesized standard compounds. Moreover, these trihalomethanols were found to be the transformation products of trihalomethanes formed during ClO_2disinfection. The results indicate that multiple LLEs can significantly improve extraction efficiencies of polar halogenated DBPs and is a better pretreatment method for characterizing and identifying new polar halogenated DBPs in drinking water.     

氧化还原修复重金属污染土壤的文献计量学分析

基于Web of Science和中国知网(CNKI)的数据源,选择对应数据库、设定年限,检索相关文献和专利,运用文献计量学方法,并借助Origin、Excel等绘图制表工具对数据结果进行了统计、分析和对比,比较直观地展现出重金属污染土壤氧化还原修复技术的总体情况、国内外发展现状和趋势、国内外发展差距,并从关键词的发展演替角度分析研究热点与方向,为氧化还原修复技术相关学科发展与研究等提供决策参考。     

南方稀土冶炼废水的特点及其处理技术研究

稀土冶炼分离过程产生大量的废水,废水中的主要污染物为氨氮、油类、COD和重金属离子等,如果不经处理直接排放,对水体会造成严重的污染.基于稀土冶炼分离工艺,阐述了稀土冶炼废水的特征,重点介绍了现有的稀土冶炼氨氮废水处理技术,包括蒸发浓缩结晶法、吹脱法、折点氯化法、化学沉淀法、离子交换法和膜分离法,分析了各种处理技术的适用性及优缺点,并对稀土冶炼分离废水处理技术进行了展望.     

综合生物塘处理城镇污水研究

报道了一种新的高效低能耗的污水处理塘系统的中试研究结果。本生物塘系统分为三个功能区域，分别为污水净化区，水质修饰区和综合利用区，水生维管束植物呈带状分布于塘系统中，在时间上和空间上进行不同搭配组合。较之传统氧化塘和一般的水生植物塘、综合生物塘的处理效果较好。ＣＯＤ、ＢＯＤ、ＴＳＳ、氮、磷等污染组分法除效率较高，细菌，病毒及诱变活性明显下降，在污水净化的同时，收获大量的水生植物及鱼，蚌等水产品，水质     

陕西渭北煤矿区地质灾害浅析

渭北煤矿区是陕西省的重要煤炭生产基地,随着矿区的开发,地质环境日趋恶化,地质灾害亦日渐增多。矿区地质灾害既普遍又严重,主要类型有:地震、活动断裂、滑坡、地面裂陷、泥石流及土壤侵蚀等。其内力型地质灾害主要受新构造运动所控制,而外力型地质灾害多与人类活动有关,即与矿区开发有关。     

长江三角洲区域发展与人口,资源,环境

历史时期,长江三角洲地区经济发展,具有与人口增长基本同步的三个发展时期。在此过程中,人口增长因素,在不同历史时期,对区域发展起着各具特色的作用。南北朝以来,人口增长过快而产生一系列人口、资源、环境失衡问题,其中某些如水域环境变化等,对当今区域经济的发展,仍然起着深刻的作用与影响。当今随着经济的纵深发展,在历史问题基础上,深化产生了许多新问题,使人口、资源、环境关系更为复杂。对此必须抓住人口增长这个主要方面,挖掘资源潜力,统一规划,加强管理,使自然-社会-经济系统的各个方面处于最佳协调状态,控制熵增,以求区域环境的久治长安、区域经济的持续增长。     

Intercomparison of Satellite Remote Sensing‐Based Flood Inundation Mapping Techniques

The objective of this study was to determine the accuracy of five different digital image processing techniques to map flood inundation extent with Landsat 8–Operational Land Imager satellite imagery. The May 2016 flooding event in the Hempstead region of the Brazos River, Texas is used as a case study for this first comprehensive comparison of classification techniques of its kind. Five flood water classification techniques (i.e., supervised classification, unsupervised classification, delta‐cue change detection, Normalized Difference Water Index [NDWI], modified NDWI [MNDWI]) were implemented to characterize flooded regions. To identify flood water obscured by cloud cover, a digital elevation model (DEM)–based approach was employed. Classified floods were compared using an Advanced Fitness Index to a “reference flood map” created based on manual digitization, as well as other data sources, using the same satellite image. Supervised classification yielded the highest accuracy of 86.4%, while unsupervised, MNDWI, and NDWI closely followed at 79.6%, 77.3%, and 77.1%, respectively. Delta‐cue change detection yielded the lowest accuracy with 70.1%. Thus, supervised classification is recommended for flood water classification and inundation map generation under these settings. The DEM‐based approach used to identify cloud‐obscured flood water pixels was found reliable and easy to apply. It is therefore recommended for regions with relatively flat topography.     

北京道路交通环境亚微米颗粒物元素组成特征及来源分析

于2011年12月和2012年8月对北京北四环道路交通环境中亚微米颗粒物(PM1)进行了采样,并对PM1的质量浓度、元素组成及主要来源进行了分析.夏季非灰霾时段PM1日平均浓度为(52.5±29.9)μg·m-3,灰霾时段PM1浓度增加到(154.2±36.3)μg·m-3;冬季非灰霾时段PM1日均浓度为(59.6±32.5)μg·m-3.采用X射线荧光光谱法(XRF)对颗粒物中元素进行分析,共得到Na、Mg、Al、Si、P、S、Cl、K、Ca、Ti、V、Cr、Mn、Fe、Ni、Cu、Zn、As、Cd、Ba和Pb等21种元素的质量浓度.其中S、Cl、K、Na、Si、Zn、Fe和Ca等8种元素含量较高,占测试元素质量浓度90%以上.污染元素浓度呈现显著的季节差异,夏季S元素浓度较高,冬季As、Cl、K、Pb、Mn、V、Cd和P等元素浓度较高.应用富集因子法发现,PM1相对PM2.5能够更好地反映人为源的元素污染特征.应用因子分析法分析出PM1的3个元素浓度贡献主成分因子:因子1反映燃煤、交通源排放和生物质燃烧,因子2反映道路及建筑扬尘贡献,因子3反映机动车排放和工业排放.因子1和因子3之和的夏季和冬季贡献比例分别高达46.8%和68.3%,表明来自机动车、燃煤、生物质燃烧等重要人为源对道路交通环境PM1浓度的贡献显著高于其他来源.灰霾期间S、As、Pb等污染元素浓度明显高于非灰霾期间,地壳元素在灰霾期间无明显浓度变化.