Leaching of elements from flue dust produced in copper scrap smelting process

To understand the features and leaching characteristics of copper (Cu) scrap smelting dust and its potential risk to environment and humans, three types of smelting dust were sampled and investigated. The dust samples were collected from the dust captured by cyclone collector, panel cooler, and bag house in a typical Cu scrap smelting process of a factory in Guangxi of China. Zinc (Zn), Cu and lead (Pb) were the main elements of the samples of cyclone collector dust (CCD), panel cooler dust (PCD), and bag house dust (BHD). There were less arsenic (As), Pb and Cu in CCD than PCD and BHD, and PCD contained more manganese (Mn), nickel (Ni), and iron (Fe) than BHD. The particle shapes of BHD appeared more regular than CCD and PCD, and energy dispersive X-ray spectroscopy analysis illustrated the compositions of selected surface areas of three samples. The size of particles ranged from 0.011 to 33.11 μm in CCD, from less than 1 μm to several mm in PCD, and from 0.832 to 363.078 μm in BHD. The main elements in leachate were Zn and Mn from CCD, Zn, cadmium (Cd) and Pb from PCD, Zn, Mn and Cd from BHD. The leaching toxicity risk of Cd, Mn, and Zn of PCD and BHD was higher than CCD.     

Chronic exposure effects of copper on growth,metamorphosis and thyroid gland,liver health in Chinese toad,Bufo gargarizans tadpoles

The impact of copper exposure on Chinese toad (Bufo gargarizans) tadpoles was investigated in this study. First, the 96h LC50 value of copper was 8.697 μM, by means of a 4 d acute toxicity test. Second, we studied the chronic effects of copper on B. gargarizans tadpoles at control, 0.025, 0.1 and 1.0 μM concentration. Survival, body length, body weight, developmental stage, incidence of metamorphic climax, and size at metamorphic climax were determined. In tadpoles developed to metamorphic climax (stage G42), liver and thyroid gland were assessed histologically. Copper at 0.1 and 1.0 μM could inhibit tadpole growth and prolong tadpole metamorphic progress relative to controls. Tadpole size (total length and weight) at stage G42 is also affected in the 0.1 and 1.0 μM treatments. In addition, histological examinations have revealed that 1.0 μM copper could cause significant pathological changes and hepatocytes degeneration in liver. Furthermore, histomorphological measurements indicated that copper at 0.1 and 1.0 μM reduced thyroid gland size, diameter and number of follicle. In conclusion, our study suggests that Cu could damage the liver and thyroid gland, so growth and metamorphosis of B. gargarizans tadpoles were inhibited resulted of disrupting liver metabolism and THs homeostasis.     

Fluorescence excitation-emission matrix combined with regional integration analysis to characterize the composition and transformation of humic and fulvic acids from landfill at different stabilization stages

Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with fluorescence regional integration (FRI) analysis was used to investigate the composition and transformation of humic acid (HA) and fulvic acid (FA) from landfill. The EEMs of HAs at different landfill ages were characterized by two typical fluorescence chromophores with Ex/Em pairs at Ex = 420-470 nm/Em = 490-530 nm and Ex = 345-375 nm/Em = 450-465 nm. EEMs of FA were featured by other two distinctly different fluorophores with Ex/Em pairs at Ex = 315-335 nm/Em = 420-440 nm and Ex = 255-275 nm/Em = 425-455 nm. The results show that HA extracted from the refuse disposed in the year of 1989 was formed by connecting small-condensed aromatic structures with protein-like chains. Compared with HA extracted from the refuse disposed in the year of 1992, HA extracted from the refuse of 1996 had a higher fluorescence intensity and lower r_(B,A) (the ratio of the fluorescence intensities of peak B and peak A) value. It contained low molar mass components, low aromatic condensation degree, and more easily oxidized substituents. This indicates that the landfill time strongly affects the EEMs characteristics of HA, and that the humification degree of HA increases with the landfill time. A red shift to a longer wavelength region and an increase of fluorescence intensity were observed when the concentration of HA was increased, suggesting that concentration had a great influence on the fluorescence characteristics of HAs. pH (2-12) also had significant effects on the fluorescence intensity, although it exerted no effect on the peak position of fluorescence of HA and FA. The results of FRI show that increasing concentration lead to more interactions among various structure components and that small molecular weight units tend to aggregate or be masked into more complicated and larger structures. The pH influence on the fluorescence intensity of HA seems mainly through molecular configuration, while the fluorescence intensity change with pH may be due to various substituents of FA.     

地铁深基坑开挖对邻近建筑物影响分析

为研究深基坑开挖对邻近建筑物的影响特征并评价其安全性,以厦门市某车站深基坑工程为例,通过构建三维有限元模型,考虑土体小应变刚度行为以及基坑-地基-基础-上部结构共同作用,计算基坑开挖引起邻近建筑物的变形值,并将柱底支座变位作为上部结构的强迫位移施加到上部结构上,然后进行结构内力分析和构件配筋验算,评价邻近建筑物的安全。研究表明:邻近建筑物越靠近基坑部分受基坑开挖影响越大,基坑开挖后,邻近建筑物结构变形主要表现为沉降和指向基坑的水平位移,结构最大水平位移为6.6 mm,自顶部向下逐渐减小,即结构发生微量倾斜;邻近建筑物地下室以沉降变形为主,主要受影响区域约为基坑围护墙后3倍的基坑开挖深度范围,沉降急剧变化区域约为1.5倍基坑开挖深度范围,地下室最大沉降为15.9 mm;受到邻近基坑开挖影响,上部结构虽然因支座变位产生内力重分布,但经检算认为整个结构仍然安全可靠。     

用CBMN法评价饮用水处理流程中有机提取物的细胞毒性

利用ＣＨＯ细胞胞质分裂阻断微核（ＣＢＭＮ）法,对某自来水厂７个处理工艺流程水中的有机提取物的细胞毒性进行了评价。在实验剂量范围内,比较了各样品的含微核的双核细胞率（ＢＮＭＮ）、核分裂指数（ＮＤＩ）和胞质分裂阻断增殖指数（ＣＢＰＩ）,实验表明,源水加氯后比源水的细胞性增大,经机加池和煤砂滤池处理后的水样毒性较大,其中煤砂滤池水毒性最大,机加池水次之,经炭吸附后的水样比炭吸附前水样的毒性下降,管网水的     

曝气＋化学絮凝法预处理环氧丙烷废水

根据环氧丙烷废水的特点，应用电化学法处理具有较高的可行性。运用电化学法处理PO废水前必须进行废水预处理，用以提高电流效率和延长极板寿命。采用曝气和化学絮凝结合的方法去除PO废水中的Ca2＋，同时去除部分COD。对曝气、无机絮凝剂（PACl、PFS）和有机絮凝剂（PAM）对PO废水处理过程中的曝气量、曝气时间、投药量、复配和沉降时间等主要影响因子进行了实验研究，通过比较Ca2＋、COD的去除效果、絮凝剂用量、沉降时间、处理成本等方面，在设定的实验参数下得到最佳预处理方案为：曝气量为2．5L／min，曝气45min，投加Na2CO3粉末24kg／t废水，充分混匀后加入PFS＋PAM复配絮凝剂。本方案具有废水处理效果好（Ca2＋的去除率为77．03％，COD的去除率为37．46％）、投药量少（（100＋7．5）g／t废水）、沉降时间短（5min）、处理成本低（0．675元／t废水）等优点。通过对比经预处理和不经预处理后电化学法对COD去除效果、电流和处理后阴极表面，验证了预处理方案的必要性与可行性。     

Association of PM2.5 pollution with the pattern of human activity: A case study of a developed city in eastern China

Recently, air pollution has attracted a substantial amount of attention in China, which can be influenced by a variety of factors, but the association between air pollution and human activity is not quite clear. Based on real-time online data (January 1, 2014, to December 31, 2014) of air pollution and meteorology reported by official sites, and demographic, economic, and environmental reform data in a statistical yearbook, the influences of meteorological factors (temperature, relative humidity, precipitation intensity, and wind force) and human activities on PM_2.5 pollution were explored. After correlation analysis, logistic regression analysis, and a nonparametric test, weak negative correlations between temperature and PM_2.5 pollution were found. In most cases, festival and morning peak hours were protection and risk factors of PM_2.5 pollution, respectively. In addition, government actions, such as an afforestation project and increasing financial expenditure for energy saving and environmental protection, could greatly contribute to alleviating pollution of PM_2.5. The findings could help officials formulate effective laws and regulations, and then PM_2.5 pollution related to the pattern of human activity would be ameliorated.

Implications: Most of the time, festival and morning peak hours are protection and risk factors for PM_2.5 pollution, respectively. Increasing the percentage of afforestation area and financial expenditure for energy saving and environmental protection could significantly reduce PM_2.5 pollution. The findings can help officials formulate effective laws and regulations, and then PM_2.5 pollution related to the pattern of human activity, especially government action, will be ameliorated.     

Antimony (Sb) – pollution and removal techniques – critical assessment of technologies

In view of increasing emissions of antimony (Sb) into the environment due to industrialization and consequent carcinogenicity, it is essential to remove this metal from the ecosystem. Antimony and arsenic (As) are analogs. Although numerous studies examined arsenic removal, few reports are available on Sb removal. In this review, various Sb removal techniques are described to understand how this process occurs and what research gaps are needed to improve efficiency. At present, surface adsorption technique is the most widely used for Sb removal. Biological treatment namely phytoremediation is also a promising method and more investigations are required in this regard. The selection of a suitable technique for a given area depends on the conditions including economic, environmental, and social conditions.     

洞庭湖演变趋势分析

洞庭湖的演变制约湖区的资源开发与环境整治。根据洞庭湖的湖底淤积与湖泊水面缩小的速率，分别论述了目平涌，南洞庭湖和东洞庭湖的自然演变趋势。结合三峡工程对洞庭湖的影响。分析了建坝后洞庭湖泊水面的变化及河流入湖三角洲的发育。