Sea water quality monitoring in Rhodes and Cos (Greece)

During the years 1983–1986, a program aiming at monitoring water quality of the most crowded beaches, as well as assessing and minimizing pollution from certain land based sources was carried out in Rhodes and Cos. The program was directed towards inspections of treatment plants as well as laboratory analyses of treated effluents from large hotels. As a result, almost one in four hotels was obliged to construct a new treatment plant. In order to help personnel to improve plant efficiency through day‐to‐day maintenance a three day seminar was held in June 1985. Sea water quality parameters (total coliforms and E. coli) were found to be well below the limits set by E.E.C. directives.     

北京大气颗粒物碳质组分粒径分布的季节变化特征

为了解有机碳(OC)和元素碳(EC)在北京大气颗粒物中的季节变化、粒径分布和来源,于2010年3月—2011年2月采用惯性撞击分级采样器采集大气颗粒物样品,热光碳分析仪测定其中有机碳和元素碳质量浓度.结果表明,OC在粗细粒子中含量相当,EC主要存在于细粒子中,在<2.1μm颗粒物中分别占(52±11)%和(70±22)%.OC存在明显的季节变化,冬、夏季高于春、秋季,而EC则表现为冬、秋季大于春、夏季.OC和EC粒径分布呈"双峰型",细粒子段峰值分别位于0.43—1.1μm和0.43—0.65μm,粗粒子段峰值均位于4.7—5.8μm.四季峰值对应的粒径段、峰宽和峰高存在差异.OC与EC粒径分布和相关性的季节变化表明,冬季OC与EC的主要来源为燃煤排放,夏季EC的主要来源为机动车尾气.     

不同区域气候条件影响下的纳帕海湿地植物叶绿素荧光特性

采用原位移地技术,研究了不同区域气候条件影响下,纳帕海4种常见湿地植物的株高、茎粗、生物量等生长特性,以及叶绿素a、叶绿素b、总叶绿素含量、叶绿素a/b值、光化学量子效率（Fv/Fm）、电子传递速率（ETR）、实际光化学量子效率（Phips2）、光化学猝灭系数（qP）、非光化学猝灭系数（NPQ）等生理生化指标,分析探讨了湿地植物对不同区域气候条件的响应差异和适应策略。研究发现气候条件的改变对湿地植物的生长、叶绿素含量及荧光参数产生重要影响。随着温度的上升,水葱Scirpus tabernaemontani和茭草两种广布种Zizania caduciflora均表现出良好的适应性,生物量、叶绿素含量、Fv/Fm、ETR、Phips2、qP值不同程度升高,生长状况良好。刘氏荸荠Heleocharis liouana也表现出较好的适应性,当气温上升到一定程度后,虽然Fv/Fm、ETR、Phips2、qP值降低,但其通过调节叶绿素含量、热耗散来减轻伤害,气候变化对其生长的影响较小。而北温带分布型的黑三棱Rhizoma scirpi yagarae对气候变化的适应性较差,当温度上升到一定程度后, Fv/Fm、ETR、Phips2、qP、NPQ都出现大幅下降,生长停滞,生物量下降,对温度上升极为敏感。可以推测,随着全球变暖,像黑三棱这样的物种,其生存将面临极大的威胁,而高原湿地生态功也将能受到损害。     

城市环境铂族金属分布特性及生态健康风险研究进展

随着铂族金属铂（Pt）、钯（Pd）、铑（Rh）被广泛应用于汽车尾气催化净化器中,这三种金属在自然界中的含量逐渐升高。越来越多的研究表明,这几种曾被认为对环境影响较小的金属的确会带来潜在的生态健康风险。本文概括了国内外城市各种环境介质的含量分布,重点分析了铂族金属的源解析方法、粒径分布特性、影响其排放的因素和其潜在的生态健康风险。就全世界的城市来看,灰尘、空气、土壤、沉积物等各种环境介质中铂族金属的含量均有显著提高,主要来源于汽车三元催化净化器。这三种金属倾向于富集在细颗粒中,行车模式是影响其排放量的重要因素,自然界的共存物质可增强它们的溶解性和迁移性,从而使它们的生物可利用性大大提高。生物体吸收这类金属后,可与体内的物质发生反应,形态发生变化,毒性增强。在以后的研究中,除了持续跟踪调查这三种金属在环境中的含量水平以外,还应加强研究这三种金属在环境中的颗粒分布、迁移转化、形态变换、生物可利用性以及生物毒性等,使我们能够更好地评估其生态健康风险,并为与之相关的应用研发、防范措施、政策制订提供引导和支持。     

人工甜味剂环境行为研究进展

人工甜味剂是一类人工合成或半合成的蔗糖取代物,由于人们对饮食健康的关注而被越来越广泛地应用于食品和饮料中.但是大多数人工甜味剂在人体内几乎不被代谢就随尿液和粪便直接排到生活污水中.近年,几种典型的甜味剂在水体中广泛被检出且浓度较高,同时研究发现部分甜味剂难以降解,因此人工甜味剂已被视为新型有机污染物而得到关注.本文就人工甜味剂在水处理设施中的行为及其在环境来源和分布的相关研究进行了综述,总结了水处理设施和水环境中甜味剂的污染特征规律,并对今后的研究进行了展望.     

不同类型竹种光合特性的比较研究

光合作用是植物生长和物质积累的基础,其光合特性是高光效竹种选育的重要生理指标。为了更好开发利用我国丰富的竹种资源,确定不同类型竹种的光合性能,掌握其合成有机同化物的能力是必须探索的一个重要问题。文章采用Li-6400光合测定仪,通过对不同地下茎类型的6个竹种光合参数和光响应的测定分析,进一步探讨不同类型竹种存在差异的生理基础,以期对不同类型竹种的选育和经营管理提供依据。试验结果表明:不同竹种净光合速率(Pn)差异显著,大木竹Bambusa wenchouensis(Wen)Q.H.Dai的净光合速率最高,Pn值平均达到8.379μmol·m-2·s-1,毛竹Phyllostachys heterocycla cv.pubescens和雷竹P.praecox cv.prevernalis次之,斑苦竹Arundinaria oleosa和苦竹Pleioblastus amarus最低,总体呈现丛生竹>散生竹>混生竹的趋势,1～2 a生竹净光合速率高于3～4 a生竹,但没有显著差异。气孔导度(Cond)、胞间C02浓度(Ci)、蒸腾速率(Tr)综合说明丛生竹的光合固碳能力最强,其中蒸腾速率与气孔导度与净光合速率关系最为紧密,是影响净光合速率的主导因子。光响应曲线表明当光强刚开始增强时,各竹种间差异较小,但随着光强的继续增加,不同竹种出现很大的差异,其中绿竹Dendrocalamus.oldhami(Munro)Keng的潜在光合能力最高,远高于其他竹种,同样表现为丛生竹>散生竹>混生竹,进一步说明丛生竹种较强的光合固碳能力,从而为今后不同类型竹种,尤其是优良丛生竹种的筛选和开发利用提供理论参考。     

广州市天河区2016年雨季挥发性有机物污染特征及来源解析

采用"GCMS/FID"在线分析方法,对广州市区2016年7月大气VOCs的污染特征及来源进行了研究,共检出了73种VOCs组分.结果表明,观测期间总VOCs的小时平均浓度为（118.83±79.40）μg·m^-3,最高值为492.42 μg·m^-3,最低值为10.54 μg·m^-3.07：00左右TVOC浓度出现高峰,说明早高峰的机动车污染对该站点的VOCs具有较大贡献;14：00左右浓度最低,与光化学损耗相关;21：00~24：00间VOCs浓度又出现高值,可能和污染源排放或边界层压缩有关.运用PMF模型解析出VOCs的5个主要来源分别是：交通污染源、溶剂使用污染、加油站污染、植物排放和餐厨废气,其贡献分别为29.79%、26.61%、24.86%、9.91%、8.84%;白天交通废气源贡献最大,而中午植物排放的贡献也明显增大;夜间溶剂污染源和加油站污染源占比上升,为该时段VOCs的主要来源.     

Investigation the effect of adding graphene oxide into diesel/higher alcohols blends on a diesel engine performance

ABSTRACT

This article aims to study the influence of the addition of graphene oxide nanoparticles (GO) to diesel/higher alcohols blends on the combustion, emission, and exergy parameters of a CI engine under various engine loads. The higher alcohols mainly n-butanol, n-heptanol, and n-octanol are blended with diesel at a volume fraction of 50%. Then, the 25 and 50 mg/L concentrations of GO are dispersed into diesel/higher alcohols blends using an ultrasonicator. The GO structures are examined using TEM, TGA, XRD and FTIR. The findings show that there is a reduction in p_max. and HRR when adding higher alcohols with diesel fuel. Regarding engine emission, there is a significant improvement in emissions formation with adding higher alcohols. The addition of GO into diesel/higher alcohols blends improves the brake thermal efficiency by 15%. Moreover, the p_max. and HRR are both enhanced by 4%. The CO, UHC and smoke formation are reduced considerably by 40%, 50 and 20%, respectively, while NO_x level is increased by 30% with adding GO. Finally, adding high percentages of n-butanol, n-heptanol, and n-octanol with diesel fuel with the presence of GO has the potential to achieve ultra-low CO, UHC, and smoke formation meanwhile keeping high thermal efficiency level.     

Population structure and community characteristics of Acer catalpifolium Rehd北大核心CSCD

Acer catalpifolium Rehd., a critically endangered tree species with an extremely limited range of distribution, is one of the 120 plant species with extremely small populations, as approved by the state forestry administration of the People's Republic of China and requires urgent rescue action. In order to comprehensively understand the population status and the future developmental trend of A. catalpifolium, the plant communities were investigated from 5 sites, including Caishenmiao (CSM), Banruosi (BRS), Zhangshancun (ZSC), Fuhusi (FHS), and Baoguosi (BGS). The population structure of A. catalpifolium as well as the species composition and community characteristics of its habitat were investigated. The results showed that A. catalpifolium is mainly distributed in the evergreen broad-leaved and deciduous broad-leaved mixed forests, in different community layers, namely, the tree layer, shrub layer, and herb layer, and is accompanied by 52, 74, and 52 plant species, respectively. Analyses of the distribution of population abundance revealed that BRS had the largest distribution of A. catalpifolium, accounting for 26.04% of the total population, followed by FHS, ZSC, BGS, and CSM, in that order. Analyses of the community characteristics revealed that the species diversity indices in FHS, BRS, BGS, and CSM were greater than that in ZSC. Analyses of the population age structure of A. catalpifolium revealed the gap in the distribution of the levels of seedlings and young trees. There were serious obstacles to the regeneration of the natural population. We concluded that the obstacle to the regeneration of the population of A. catalpifolium might be caused by the high competitive pressure from the dominant species and the micro-environment in the forest. Understanding the community characteristics and the population structure of A. catalpifolium could provide a theoretical foundation for its reintroduction and recovery. © 2018 Science Press. All rights reserved.     

垂直潜流人工湿地堵塞微观概念模型的提出

根据垂直潜流人工湿地发生堵塞的成因主要是基质层中不可滤物质积累的结论,在分析垂直潜流人工湿地堵塞物形态及成分粒径的基础上,首次提出了基质间不可滤物质积累微观概念模型的假设;并根据微观概念模型,在考虑生物膜、无机物积累等动态变化因素条件下提出基质间完全堵塞所需时间、基质表面发生雍水所需时间及基质渗透系数随时间变化的关系.