Characteristics and sources of heavy metal pollution in desert steppe soil related to transportation and industrial activities

Environmental Science and Pollution Research - A study area was selected from the industrial region of Gaoshawo Town, Yanchi County, Ningxia, to explore the level of heavy metal pollution in desert...     

耐盐菌群对高含盐染料模拟废水的脱色实验研究

目前生物法处理高含盐染料废水的研究鲜有报道,实验对3种不同来源的活性污泥进行耐盐驯化,耐盐程度达到25%NaC l(w/w),用驯化得到的耐盐菌对高含盐染料K-2BP模拟废水进行厌氧脱色研究,脱色率达100%,并对其脱色机理进行了初步探讨,同时,进行了耐盐菌的脱色广谱性实验,结果表明驯化耐盐菌对所选取的13种不同结构的染料均有很高的脱色效果。研究为常规生物法应用于高含盐废水的处理提供了实验基础和理论依据。     

不同高度大气颗粒物中多环芳烃的粒径分布

在天津地区20m,40m和60m三个不同高度同步采集冬季大气颗粒物中PM10样品,测定了16种多环芳烃(PAHs)含量．不同高度PM10中PAHs的含量均表现出大气颗粒物中随高度先增后降的趋势,颗粒物质量中值直径(MMD)也呈现类似规律,但PAHs总浓度的MMD则呈向上递增的趋势．不同高度PAHs的粒径分布差别不大,高分子量的PAHs主要集中在空气动力学直径Dp＜2um的细颗粒上,而Dp＞2um的粗颗粒上低分子量的PAHs相对较多．     

Effect of selected pesticides and their ozonation by-products on gap junctional intercellular communication using rat liver epithelial cell lines.

The non-genotoxic effects of two commonly used pesticides, 1,1-bis (p-chlorophenyl)-2,2,2-trichloroethane (DDT) and malathion, and one widely used commercial insect repellent N,N-diethy-m-toluamide (DEET) on gap junction intercellular communication (GJIC) were determined using a rat liver epithelial cell line. Malathion and DDT reversibly inhibited GJIC in a treatment time- and dose-dependent manner at non-cytotoxic doses, whereas, DEET did not inhibit GJIC. Malathion was very reactive with ozone, while DEET and DDT did not react to any appreciable extent with ozone. The mixtures of ozonation products from malathion and DEET did not inhibit GJIC. The mixtures of ozonation by-products formed from DDT inhibited GJIC, but to a lesser extent than did DDT, itself. These results suggest that ozone can effectively remove malathion from solution without forming GJIC-toxic products, but is less effective in eliminating DEET and DDT from solution.     

列车运行安全性、平稳性的控制因素及评估准则

既有线的提速及高速铁路的修建 ,标志着我国铁路迈上了一个新的台阶 ,同时 ,列车运行的安全性和稳定性问题也愈显突出。高速、安全和舒适是高速铁路运输得以实现的三大要素 ,本文从动力学角度 ,通过不同的参数 ,分析了目前国内外列车运行安全性和平稳性的标准 ,探讨了列车脱轨、倾覆的不安全因素和旅客乘坐舒适性的各项指标 ,并提出了评估准则     

城市,让生活更美好

<正>世界博览会(World Exhibition or Exposition),是由一个国家的政府主办,有多个国家或国际组织参加,以展现人类在社会、经济、文化和科技领域取得成就的国际性大型展示会。其特点是举办时间长、展出规模大、参展国家多、影响深远。     

正压生物防护服研究进展

正压生物防护服是针对高危生物污染环境作业人员防护而研制的一类个体防护装备。本文从防护服材料、正压形成与保持、微环境、人体工效学等方面出发,综述了正压生物防护服关键技术研究的成果与不足。提出以功能通用化、监控自动化、使用信息化、研制规范化为特点的正压防护服是未来发展的趋势。     

Lead-induced oxidative damage in steriled seedlings of Nymphoides peltatum

The effects of increasing concentrations of lead (Pb) on Pb accumulation and its influence on nutrient elements, malondialdehyde (MDA) content, generation of superoxide anion (O₂ ^?·), hydrogen peroxide (H₂O₂) content, antioxidant enzymes activities, soluble protein, and photosynthetic pigment, as well as chloroplast ultrastructure in steriled seedlings of Nymphoides peltata (S. G. Gmel.) Kuntze were investigated in order to understand Pb-induced toxicity. The accumulation of Pb was found to increase in a concentration-dependent manner. Nutrient elements (Ca, K, Fe, Mn, and Mo) were also affected. MDA content and O₂ ^?· generation rate increased progressively, while H₂O₂ content first boosted up at a low Pb concentration of 12.5 μM but then declined. Guaiacol peroxidase and catalase activities increased alternately, while superoxide dismutase activity gradually fell. Negative correlations were found between Pb and soluble protein and photosynthetic pigment. Moreover, Pb exposure resulted in a significant damage of chloroplasts. Taken together, these findings supported the hypothesis that Nymphoides peltatum underwent oxidative stress induced by Pb. In addition, both the disorder of nutrient elements and the damage to the ultrastructure of chloroplasts were indicative of general disarray in the cellular functions exerted by Pb.     

The Comparative Approach on Outdoor Leisure Behavior of Urban Elderly People: A Case Study in Beijing

Abstract

With the income increase of elderly people in Beijing and the improvement of leisure facilities since 2000, the quality of elderly people leisure life in Beijing has obviously increased compared to ten years ago. According to the investigation and comparative analysis on more than 900 elderly people, who usually exercise in public parks in Beijing City, we have found out several new features of elderly people’s outdoor recreation in Beijing: the increase of the leisure time, the expansion of leisure space, the individuation of interest and the diversification of consumption. The leisure life quality evaluation index system of urban elderly people can be built based on these analyses. In order to accommodate the development tendency of elderly people’s demand for leisure diversification, we should strengthen the organization and management of elderly people’s leisure activity in urban construction, and pay more attention to function complementation between communities and parks.     

东湖沉积物和间隙水中不同形态磷的垂直分布

对武汉东湖3个样点沉积物及间隙水不同形态磷的浓度进行了测定,结果表明：(1)位于排污区附近的1号点沉积物TP浓度最大,位于湖心位置的2号点TP浓度最小;(2)3个样点沉积物中不同形态磷含量均为Fe P（铁结合态磷）所占比例最大（3885%～5914%）,LP（不稳定态磷）所占比例最小（027%～149%）;(3)东湖沉积物中活性磷含量较高,有较大的磷释放潜力;(4)东湖表层沉积物间隙水中正磷酸盐和上覆水中正磷酸盐存在较大浓度梯度,浓度梯度可能不是间隙水和上覆水之间磷交换的决定性因素