北京大气颗粒物和重金属铅干沉降通量及季节变化

为了解大气颗粒物和重金属铅(Pb)干沉降通量的变化规律,采用聚氨酯泡沫膜片为代用面联合干湿沉降自动观测设备,于2013年12月~2014年11月在北京城区采集了颗粒物干沉降,利用微波消解和电感耦合等离子体质谱仪对样品中全量Pb和水溶性Pb进行了测试分析.结果表明,北京大气颗粒物和Pb干沉降通量分别为0.84 t·(hm~2·a)~(-1)和7.56mg·(m~2·a)~(-1),呈现出春季冬季秋季~夏季的特征.大气颗粒物中水溶性Pb干沉降通量为3.14 mg·(m~2·a)~(-1),占Pb干沉降总量的43%,这一比例呈现出冬春季高于夏秋季的特征.人为源排放不仅增加了大气颗粒物和Pb的干沉降通量,也改变了水溶性Pb干沉降通量的季节分布.研究结果对科学评估重金属沉降的生态影响和健康效应提供了科学基础,同时凸显了消减人为源重金属排放的重要性.     

林丹短期暴露下的斑马鱼(Brachydanio rerio)组织学变化

以斑马鱼(Brachydaniorerio)为受试生物,初步探讨了林丹对斑马鱼的急性毒性以及不同浓度(0.01μg·L-1、1.0μg·L-1、100.0μg·L-1)的林丹暴露36d后对斑马鱼鳃和肝组织结构变化的影响.结果表明,林丹对斑马鱼96h-LC50为97.98μg·L-1,95%可信限为94.38￣101.72μg·L-1.当林丹浓度为0.01μg·L-1时,斑马鱼的鳃和肝组织结构未发生明显变化,而暴露在1.0μg·L-1和100.0μg·L-1林丹溶液中的斑马鱼的鳃和肝组织结构变化显著.斑马鱼鳃组织变化为:上皮细胞残损、脱落,鳃小片上皮细胞水肿,柱细胞变形.斑马鱼肝组织变化为:部分肝细胞肿大,细胞核萎缩变形或偏离细胞中心,胞质疏松,空泡明显增加,细胞质中可见脂沉积.与1.0μg·L-1林丹暴露相比,暴露在100μg·L-1林丹溶液中的斑马鱼鳃和肝组织结构受到的损害更为严重.     

Alteration of dominant cyanobacteria in different bloom periods caused by abiotic factors and species interactions

Freshwater cyanobacterial blooms have drawn public attention because they threaten the safety of water resources and human health worldwide. Heavy cyanobacterial blooms outbreak in Lake Taihu in summer annually and vanish in other months. To find out the factors impacting the cyanobacterial blooms, the present study measured the physicochemical parameters of water and investigated the composition of microbial community using the 16S rRNA gene and internal transcribed spacer amplicon sequencing in the months with or without bloom. The most interesting finding is that two major cyanobacteria, Planktothrix and Microcystis, dramatically alternated during a cyanobacterial bloom in 2016, which is less mentioned in previous studies. When the temperature of the water began increasing in July, Planktothrix appeared first and showed as a superior competitor for M. aeruginosa in NO₃^?-rich conditions. Microcystis became the dominant genus when the water temperature increased further in August. Laboratory experiments confirmed the influence of temperature and the total dissolved nitrogen (TDN) form on the growth of Planktothrix and Microcystis in a co-culture system. Besides, species interactions between cyanobacteria and non-cyanobacterial microorganisms, especially the prokaryotes, also played a key role in the alteration of Planktothrix and Microcystis. The present study exhibited the alteration of two dominant cyanobacteria in the different bloom periods caused by the temperature, TDN forms as well as the species interactions. These results helped the better understanding of cyanobacterial blooms and the factors which contribute to them.     

安全农居四字歌

.....口..农村震害,建造街房,农民盖房,建址不当,建筑材料,物筑堵体,农居工租,场址选择,地羞安全,用料保质,堵体构架,结构科学,房塌最‘漆,大计育年,常按习惯,河启暗边,旧瓦碎砖,结构松傲,地震安全,德定地段,沟柑要宽,更乃关健,紧密相联,层层梁圈,人财     

浅析紧急救援的综合性

2006年初,国务院发布了《国家突发公共事件总体应急预案》。其目的是要提高政府保障公共安全和处置突发公共事件的能力,最大程度地预防和减少突发公共事件及其造成的损害,保障公众的生命财产安全,维护国家安全和社会稳定,促进经济社会全面、协调、可     

植树节所不能拯救的森林病

发现一个“有趣”的现象。打开某知名网站的环保频道,有关于植树造林的专题。近期的新闻有一些,大抵是有关植树节活动。再看早期的新闻,居然一下就上跨到去年的同一时期。当然,去年的同一时期也要迎接植树节。     

换房换出来的住地游

在一个城市呆得久了,就会想要到别的城市去看看,尝试一种不同的生活。对于很多人而言,这种到其它城市走走看看的想法也只能是一种想法,因为一旦离开家,就要考虑如何到达目的地？如何解决吃、喝、拉、撒、睡的问题,这些在家中根本不用发愁的事情,在家门之外就要和金钱、时间搭上关系。     

Study of the pyrolysis of ionic liquid [Bmim]Cl-pretreated mango pit at low temperature

Journal of Material Cycles and Waste Management - In the present work, mango pit was used to study the feasibility of converting ionic liquid-pretreated biomass into biofuel and activated biochar...     

Large-scale utilization of desulfurization ash and fly ash for unfired production of high-strength road-base stones

Journal of Material Cycles and Waste Management - This paper utilizes desulfurization ash (DA), fly ash (FA) and ordinary Portland cement (OPC) to prepare unfired high-strength road-base stones by...     

Biochar and cattle manure amendments improve the quality of green waste compost as growing substrate for Centaurea cyanus

Journal of Material Cycles and Waste Management - This study aimed at investigating the impacts of different percentages of biochar (BC) (at 0, 15, and 25%; by vol.) and/or cattle manure (CM) (at...