重庆市冬季PM_(2.5)及气态污染物的分布特征与来源

利用重庆市大气污染物监测站2013年冬季(2013年11月—2014年1月)的实测数据,分析PM2.5及相关气态污染物(SO2、NO2、O3)的时空特征,并采用轨迹聚类与PSCF(潜在源贡献因子)分析污染物来源.结果表明:除ρ(O3)以外,其他3种污染物质量浓度的月际变化趋势基本一致,均呈12月升高、1月降低的特征;污染物空间分布不均,其中ρ(PM2.5)和ρ(NO2)在工业区和人口密集区较高,ρ(SO2)南高北低,ρ(O3)城区低于郊区.ρ(SO2)、ρ(NO2)与ρ(PM2.5)均呈显著正相关,其中ρ(SO2)与ρ(PM2.5)的R(相关系数)在城、郊区分别为0.71、0.65,ρ(NO2)与ρ(PM2.5)在城、效区的R分别为0.73、0.56;而ρ(O3)与ρ(PM2.5)未表现出显著相关.ρ(SO2)、ρ(NO2)与ρ(PM2.5)的相关性高低可在一定程度上说明二次气溶胶的污染程度,ρ(O3)与ρ(PM2.5)的相关性受到PM2.5来源和污染程度的影响.轨迹分析结果显示,重庆市2013年冬季主要受东北方向气流影响;聚类分析表明,重庆市11月没有表现出明显的PM2.5外来输送特征,但12月和1月的PM2.5外来输送特征明显,并且不同方向的气流污染物浓度差异也较大.PSCF分析发现,重庆市冬季PM2.5、SO2、NO2、O3主要来源于本地和周围城市局地传输,同时还受南宁、贵阳、遵义、达州等地的影响.     

喷丸强化对超高强度钢耐腐蚀性能的影响

目的提高舰载机结构疲劳关键部位的主体材料超高强度钢的耐蚀性能。方法基于实测的环境数据编制加速腐蚀试验环境谱,针对喷丸和未喷丸超高强度钢试验件在实验室条件下开展加速腐蚀试验,从宏观/微观形貌、质量损失、腐蚀速率和表面粗糙度等方面表征腐蚀行为,分析讨论喷丸强化对超高强度钢耐腐蚀性能的影响。结果超高强度钢腐蚀初期为局部点蚀,然后转变为全面均匀腐蚀。喷丸强化延缓了腐蚀形态转变的时机,喷丸试验件腐蚀速率约为未喷丸试验件的75%,加速腐蚀当量为3 a,未喷丸和喷丸试验件表面平均粗糙度分别为5.67mm和4.16mm,前者为后者的1.36倍。结论通过质量损失率、腐蚀速率和表面粗糙度的对比分析知,喷丸强化明显提高了超高强度钢的耐腐蚀性能。     

纳米二氧化钛的毒性研究进展

随着纳米技术的迅猛发展,纳米材料越来越广泛地应用于社会科技生活的各个领域,在给人们生活带来便利的同时,纳米毒性也日益受到越来越广泛的关注。然而目前纳米毒性关注的焦点多集中在碳纳米管等早先发现的纳米材料上,却对纳米TiO2这一取得方便、制备容易、应用广泛、产量最大的纳米材料关注不足。本文从细胞水平和在体水平综述了纳米TiO2毒性研究进展,阐述了纳米TiO2对人体及其它生物潜在的生物效应,并提出对纳米TiO2进行安全性评估的必要性。     

岩溶对黄壁庄水库副坝坝基渗流场的影响分析

黄壁庄水库副坝曾多次出现管涌流沙和塌坝现象,其影响因素诸多,而基岩中溶洞和破碎带的存在是重要影响因素之一。为此,选择溶洞坝段进行三维渗流场的数值模拟,分析了溶洞的存在与否对坝基渗流场的改造作用以及对坝体渗透坡降的影响,并时设置防渗墙的必要性进行讨论,为除险加固措施的制订提供参考。     

Biogeochemistry of mercury in the Amazonian environment

In this paper, the processes that affect mercury (Hg) cycling in the Amazonian environment were reviewed, criticized and new directions of research are proposed. The discussion of the origin of the mercury contamination, whether natural or anthropogenic is marked by a lack of fundamented arguments from both sides. Undoubtedly mercury inputs from gold mining have locally increased environmental concentrations, but in the whole Amazon, these loads would be insignificant, considering the high concentrations observed by some authors in remote soils. A reasonable process that should explain these elevated concentrations in soil is that B horizons function as a mercury "sponge" that have been accumulating mercury over a geological time scale, releasing it back to cycling during erosion and forest fires. The environmental degradation of the Amazonian forest due to human activities is probably enhancing the release of that mercury to the cycle. Mercury transformations in reduced, anoxic environments--sediments and waters--are also a key problem for the understanding of the environmental methylation. The studies that have been carried out in the Amazonian environment are too restricted and results permit only circumstantial conclusions. Large efforts must be directed to monitoring programs considering time and space variability.     

Occurrence of bisphenol A in surface water and uptake in fish: evaluation of field measurements

In this study the actual presence of the suspected endocrine disrupter Bisphenol A (BPA) in water systems was studied in the Netherlands. BPA was shown to be present in Dutch surface water at levels up to 330 ng/l, and one occasional observation of 21 microg/l. During the three sampling periods, 60-80% of the samples, most from marine and estuarine locations, contained BPA levels below the limit of quantification (14-40 ng/l). At a selected number of locations the presence of BPA in fish was studied, which showed that BPA varied from 2 to 75 ng/g in the liver and 1 to 11 ng/g in the muscle. Based on present measured concentrations in surface water and on literature derived toxicity data it was concluded that ecotoxicological effects nor estrogenic effects are likely to occur in the field situation.     

第三方逆向物流在WEEE处理中的应用

概述了中国废弃家用电器与电子产品产生现状,分析了其环境危害性,指出了目前无序回收处理存在污染环境、浪费资源等问题。参照发达国家对废弃电子电器设备的管理,针对中国实际情况,分析第三方逆向物流回收模式在废弃电子设备中的应用。鉴于中国国家环保总局公布的《点子废物污染环境防治管理办法》,结合第三方逆向物流回收模式的优劣比较,得出最适合中国国情的第三方物流模式。同时国家也积极展开了回收试点工作,并鼓励其他公司为中国的环境管理事业作出贡献。     

亚马孙河流域汞的生物地球化学研究

本文阐述和评论了影响亚马孙河流域汞循环的途径,并提出了新的研究方向.对于汞污染源的讨论,无论是天然的还是人为的,都缺乏基本的论据.毫无疑问,黄金矿山释放的汞已经局部地提高了环境中汞的浓度,但在整个亚马孙河流域,与一些学者在远离金矿的土壤中测出的高浓度数值相比,这种负荷并不显著.土壤中汞的高浓度现象有一个合理的解释,即B层(淀积层)是在地质时期蓄积了汞的"海绵体",当发生侵蚀和森林火灾时,汞又被释放回循环体系.源于人类活动导致的亚马孙河流域森林的环境退化,很可能会加速汞的释放.汞在还原性的缺氧环境--沉积物和水中--的转换也是理解汞的环境甲基化的一个关键性问题.在亚马孙河流域环境所做的这项研究非常有限,研究结果只能得出受限的结论,进一步的工作应注重结合时间和空间变化的监测计划.     

The distribution of polynuclear aromatic hydrocarbons in ambient air particulates in Singapore

Ambient air particulates were collected using high volume samplers at seven locations throughout Singapore. The particulates were analyzed for eleven polynuclear aromatic hydrocarbons (PAH) using high performance liquid chromatography (HPLC) with fluorescence detection. Several sample preparation techniques were used to determine which method would yield the most PAHs from the bulk sample matrix. PAH profiles (standardised against the concentration of benzo(a)pyrene) were obtained to characterise the different sampling sites chosen.     

上海西南郊区PM2．5污染状况研究

研究了上海西南郊区PM2．5（细颗粒物）污染特征,分析了PM2．5与其它污染因子和气象因子相关性,并提出了PM2．5污染控制建议。