大气气溶胶酸度的研究进展

大气气溶胶的环境效应、气候效应和健康效应均与气溶胶的物理化学性质直接相关,其中大气气溶胶酸度是其重要的性质之一。大气气溶胶酸度对酸沉降、灰霾的形成具有重要作用,并影响大气非均相化学反应,相关研究已成为国际研究的热点。对国内外学者近年来在大气气溶胶酸度对大气环境与人体健康的影响、大气气溶胶酸度的影响因素与变化规律、大气气溶胶酸度/酸化缓冲能力的测定与计算方法、大气气溶胶酸性成分采集系统等方面的研究进展作了较系统的综述,并对大气气溶胶酸度研究未来的发展进行了展望。     

中国规划环境影响评价中存在的问题与对策

本文对我国规划环境影响评价中存在的问题进行了分析,提出完善规划环评机制,强化规划环评的审批管理．加强有关规划环评技术方法的研究,提高规划环评审批者及相关专家的业务水平等推进规划环评的措施．     

东川市土地退化（荒漠化）及其防治

分析了东川市土地退化现状：土地退化以水蚀为主,退化土地面积占总土地面积38．5％。土地退化类型主要有土壤退化、土地沙石化、土地石质化和侵蚀劣地。文章还探讨了东川市土地退化的原因,提出了土地退化防治对策。     

锌离子慢性暴露对中华大蟾蜍蝌蚪生长发育的影响

为评价水域环境中Zn~(2+)对两栖动物的毒性影响,本研究以中华大蟾蜍(Bufo gargarizans)蝌蚪为试验材料,对G26期蝌蚪进行了0、10、50、100和500μg·L~(-1)Zn~(2+)的慢性水体暴露直至蝌蚪发育至变态高峰期(G42期)。分别于暴露15 d和30 d后取样测定蝌蚪全长、体长、体重和发育分期各指标;此外,分析了Zn~(2+)慢性水体暴露对变态率、变态高峰期(G42)蝌蚪的全长、体长、体重、后肢长和骨骼发育的影响。结果表明:暴露15 d时,各浓度Zn~(2+)对中华大蟾蜍蝌蚪的生长发育均未造成显著影响,而持续暴露30 d后,500μg·L~(-1)Zn~(2+)处理组蝌蚪的生长发育受到显著抑制;各浓度Zn~(2+)慢性暴露均导致中华大蟾蜍蝌蚪变态率的下降,其中500μg·L~(-1)Zn~(2+)处理组的变态率最低;500μg·L~(-1)Zn~(2+)慢性暴露导致G42期中华大蟾蜍蝌蚪的形态指标(全长、体长、后肢长)和骨化程度均受到显著抑制。研究表明,水环境中高浓度锌对中华大蟾蜍幼体的生长发育和变态具有潜在的危害,水域锌污染所引发的毒理效应予以重视。     

美人蕉有机酸组分对铜绿微囊藻的化感作用

对美人蕉叶片水浸提液进行液液萃取得到美人蕉有机酸组分,研究了美人蕉有机酸组分对铜绿微囊藻化感抑制作用,实验结果表明,美人蕉有机酸组分对铜绿微囊藻生长具有低促高抑作用,13.3 g/L和20.0 g/L处理组6 d 后抑制率分别达到98.57%和99.37%,铜绿微囊藻在高浓度美人蕉有机酸组分下,叶绿素含量逐渐降低,总超氧化物歧化酶(T-SOD)和过氧化氢酶(CAT)活性出现先增大后减小,说明美人蕉有机酸组分可能通过对铜绿微囊藻抗氧化酶系统逐渐损伤,最终藻类死亡.通过气相色谱-质谱(GC-MS)分析,鉴定出美人蕉有机酸组分共含有32种有机酸成分,其中饱和脂肪酸18种、不饱和脂肪酸7种、芳香酸5种以及酚酸2种.     

A2O氧化沟缺氧区三维流场模拟及结构形式优化

以FLUENT软件为工具,选用三维RNG k-ε紊流数学模型对重庆井口污水厂A²O氧化沟缺氧区内的流场进行模拟,分析了缺氧区内流场分布不均匀及沉泥的原因,提出了水下推进器的合理设置位置与导流墙的合理设置方式,并对优化后的缺氧区进行了模拟计算。通过优化后模拟的结果可见,在相同的功率密度下,缺氧区内的流场得到了较均匀的分布,流速从原来的0.131 m/s提升到0.204 m/s,减少了能量的损失。底部的流速也从原来的0.140 m/s提升到0.226 m/s,有效的防止或减少了沟中的污泥沉积。优化的结果对实际工程的设计也有一定的指导意义。     

Application of a novel cold activated carbon fiber-solid phase microextraction for analysis of organochlorine pesticides in soil

A novel and simple analytical procedure using cold activated carbon fiber-solid phase microextraction (CACF-SPME) was applied to determine organochlorine pesticides (OCs) in soil samples. The pesticides in this study consist of alpha -, beta -, gamma -, and delta -hexachlorocyclohexane (HCH). By heating the sample while cooling the fiber, the developed method not only provides better performance in terms of sensitivity, linearity and recovery but also offers shorter adsorption procedure than that of traditional headspace-solid phase microextraction (HS-SPME). The experimental conditions such as the amount of water, adsorption time and adsorption temperature were optimized. Matrix effects were investigated with different types of soils. We concluded that using the standard addition method was required for quantification purposes. The limits of detection obtained using the proposed method range from 0.01 to 0.05 ng/g, and the recoveries for CACF-SPME are in the range of 80.01% to 89.68% with relative standard deviation (RSDs) better than 8.60%. The proposed method was further applied to determine OCs in real agricultural soil. The results are in good agreement with those obtained using traditional ultrasonic extraction. The research demonstrates the suitability of the CACF-SPME for the analysis of OCs in soil.     

昆明市东川区农业旱灾风险区识别研究

昆明市东川区是云南省农业旱灾危害较为严重的区域之一。利用2000-2007年东川区各乡镇历史灾情等数据资料,应用风险分析理论、效用理论、因子-成份分析方法等理论方法,在分别研究致灾风险度、承灾体易损性及地域人群对农业旱灾心理反响等基础上,构建了东川区农业旱灾风险评价模型。初步揭示出东川区农业旱灾风险度呈现出自南向北、自西向东逐渐增强的空间态势;识别出极高风险区、高风险区、中风险区和低风险区等4个农业旱灾风险区;发现东川区各地农业旱灾综合风险度、致灾风险度、承灾体易损度以及地域人群对旱灾的心理响应值等指数之间普遍存在着明显的正相关。     

The gap report of global climate change mitigation,finance, and governance after the United States declared its withdrawal from the Paris Agreement

On 1 June 2017, the US President Donald Trump officially announced the withdrawal from the Paris Agreement, thus the study on the reasons of withdrawal, the potential impacts, and coping strategies has become a focus among policy circles and of the international community. Based on the self-developed US Policy Assessment Model, this paper systematically evaluates the three potential “major deficits” in terms of mitigation, climate finance, and global climate governance, as a result of the US withdrawal from the Paris Agreement and puts forward policy suggestions for coping with such transformations accordingly. The study shows that the United States ’withdrawal from the Paris Agreement will affect the existence and implementation of successive climate policies and result in an additional 8.8–13.4% increase in the global emissions reduction deficit. The United States’ withdrawal will also deteriorate the existing climate finance mechanism. The Green Climate Fund (GCF)’s funding gap will increase by US$2 billion, while the gap of long-term climate finance will increase by about US$5 billion a year. Either the China–EU or the “BASIC plus” mechanism could fill the governance deficit caused by the United States and the lack of political momentum may continue for a while in the future.     

Removal of nitrogen from wastewaters by anaerobic ammonium oxidation (ANAMMOX) using granules in upflow reactors

Nitrogen pollution of waters has sometimes caused severe eutrophication, leading to the death of fishes and most aquatic life. There is therefore a need for efficient and cost-effective methods to remove nitrogen from ammonium-rich wastewaters. Anaerobic ammonium oxidation (ANAMMOX) is a promising process to remove nitrogen because this process directly oxidizes ammonium (NH₄ ⁺) to dinitrogen gas (N₂) under anoxic condition. Nonetheless, a challenge of this process is that chemolithoautotrophic Anammox bacteria grow slowly at the beginning, thus resulting in low Anammox biomass and instability of reactors. Such issues can be overcome by granulation of the Anammox sludge. Here, we review the characteristics of the Anammox bacteria, and the formation, structure and flotation of Anammox granules under high hydraulic loadings. We also evaluate the performances of full-scale granular Anammox processes. The major points are: 1) Anammox bacteria secrete a large amount of extracellular polymeric substances (EPS), up to 415 mg g^?1 of volatile suspended solids (VSS), containing many hydrophobic functional groups that facilitate biomass granulation. 2) Granulation enhances the sludge settling property and retention time, which contributes to the extremely high nitrogen removal rate of 77 kg m^?3 d^?1 of Anammox upflow reactors. 3) Flotation of Anammox granules frequently occurs under nitrogen removal rate higher than 10 kg m^?3 d^?1, which is mainly due to the overproduction of EPS under high hydraulic conditions.